Papers for Monday, Oct 28 2024

In recent astronomical discussions, attempts have been made to link the known dwarf nova Z Cam to historical celestial events, particularly the "guest star" phenomenon reported in China in 77 BCE. Despite other suggestions and the problems with regard to the location of the event in 77 BCE, its identification with Z Cam is used in the Variable Star IndeX (VSX) of the AAVSO and in several research papers that aim to derive knowledge on the evolution of cataclysmic variables. Through the reconstruction of the super-constellation of the Purple Palace in the Han Dynasty, we found that Z Cam is actually located outside this enclosure, contradicting the records of the 77 BCE guest star being "within the Purple Palace". With newly found text versions of the guest star in 77 BCE, we narrowed down the position given therein. Combined with a new analysis of accompanying divination text leads to the conclusion that this guest star was actually a comet. Finally, through meticulous examination and comparison, we conclude that the guest star of 369 CE appears the most plausible candidate for Z Cam's historical counterpart, aligning with both textual evidence and modern astronomical observations.

A primary goal of exoplanet science is to measure the atmospheric composition of gas giants in order to infer their formation and migration histories. Common diagnostics for planet formation are the atmospheric metallicity ([M/H]) and the carbon-to-oxygen (C/O) ratio as measured through transit or emission spectroscopy. The C/O ratio in particular can be used to approximately place a planet's initial formation radius from the stellar host, but a given C/O ratio may not be unique to formation location. This degeneracy can be broken by combining measurements of both the C/O ratio and the atmospheric refractory-to-volatile ratio. We report the measurement of both quantities for the atmosphere of the canonical ultra hot Jupiter WASP-121 b using the high resolution (R=45,000) IGRINS instrument on Gemini South. Probing the planet's direct thermal emission in both pre- and post-secondary eclipse orbital phases, we infer that WASP-121 b has a significantly super-stellar C/O ratio of 0.70$^{+0.07}_{-0.10}$ and a moderately super-stellar refractory-to-volatile ratio at 3.83$^{+3.62}_{-1.67} \times$ stellar. This combination is most consistent with formation between the soot line and H$_2$O snow line, but we cannot rule out formation between the H$_2$O and CO snow lines or beyond the CO snow line. We also measure velocity offsets between H$_2$O, CO, and OH, potentially an effect of chemical inhomogeneity on the planet day side. This study highlights the ability to measure both C/O and refractory-to-volatile ratios via high resolution spectroscopy in the near-infrared H and K bands.

With the new discoveries enabled thanks to the recent space missions, stellar physics is going through a revolution. However, these discoveries opened the door to many new questions that require more observations. The European Space Agency's Human and Robotic Exploration programme provides an excellent opportunity to push forward the limits of our knowledge and better understand stellar structure and dynamics evolution. Long-term observations, Ultra-Violet observations, and a stellar imager are a few highlights of proposed missions for late-type stars that will enhance the already planned space missions.

The origin of nonthermal broadening in solar spectra is one of the long-standing questions in solar physics. Various processes have been invoked - including unresolved flows, waves, and turbulent processes - but definitive answers are lacking. To investigate the physical processes responsible for nonthermal broadening, we examine its relation with the angle between the magnetic field and the line of sight in three different closed-field regions above plage regions at different locations on the solar disk. We obtained the nonthermal width of transition-region Si IV 1403 Å spectra observed in active regions by the Interface Region Imaging Spectrograph, after subtraction of the thermal and instrumental line broadening. To investigate the dependence of the measured broadening on the viewing angle between the line of sight and magnetic field direction, we determined the magnetic field direction at transition-region heights using nonlinear force-free extrapolations based on the observed photospheric vector magnetic field taken by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. We found that the nonthermal broadening shows a correlation with downward motion (redshifts)and alignment between the magnetic field and the observer's line-of-sight direction. Based on the observed correlations, we suggest that velocity gradients within plasma flowing down along the magnetic field may lead to a significant portion of the observed nonthermal broadening of transition-region spectral lines in closed fields above plage regions.

In this work we improve the dynamic-evolutionary framework of two massive clusters at intermediate redshifts: Cl 0024+17 at $z \sim 0.4$ and MS 0451-03 at $z \sim 0.5$. The spectroscopic galaxy members were selected from Moran et al. (2007a), which combine optical and UV imaging with spectroscopy. Using a set of dynamic estimators with different approaches, our results show that both Cl 0024+17 and MS 0451-03 are non-relaxed systems with distinct dynamical configurations. Cl 0024+17 exhibits a disturbed kinematics, displaying significant gaps and a velocity dispersion profile suggesting a merger. This is confirmed by the presence of previously reported substructures and new ones identified in this study. MS 0451-03 appears less disturbed than Cl 0024+17, indicating by the significant segregation between late and early-type galaxies, with the latter occupying more central regions of the projected phase-space. However, five previously unobserved substructures and non-Gaussianity in the velocity distribution indicate that MS 0451-03 is also out of equilibrium. In both clusters, there are substructures infalling onto the systems, indicating key moments in their assembly histories and potential effects on the pre-processing of galaxies within these subgroups. This is suggested by the high percentage of early-type galaxies outside $R_{200}$ (approximately $83\%$) in the case of CL 0024+17. This work reinforces the importance of more detailed dynamical analysis of clusters to better characterize their evolutionary picture.

The properties of luminous, blue (a.k.a. Blue Monsters), super-early galaxies at redshift $z>10$ have been successfully explained by the attenuation-free model (AFM) in which dust is pushed to kpc-scales by radiation-driven outflows. As an alternative to AFM, here we assess whether *attenuation-free* conditions can be replaced by a *dust-free* scenario in which dust is produced in very limited amounts and/or later destroyed in the interstellar medium. To this aim we compare the predicted values of the dust-to-stellar mass ratio, $\xi_d$, with those measured in 15 galaxies at $z>10$ from JWST spectra, when outflows are not included. Our model constrains $\xi_d$ as a function of several parameters by allowing wide variations in the IMF, dust/metal production, and dust destruction for a set of SN progenitor models and explosion energies. We find $\log \xi_d \approx -2.2$ for all systems, indicative of the dominant role of SN dust production over destruction in these early galaxies. Such value is strikingly different from the data, which instead indicate $\log \xi_d < -4$. We conclude that dust destruction alone can hardly explain the transparency of Blue Monsters. Other mechanisms, such as outflows, might be required.

We propose a model that can describe the entire range of FRBs, from non-repeating to highly prolific repeaters. Coherent radio waves in these bursts are produced in the polar cap region of a magnetar, where magnetic field lines are open. The angle between the rotation and magnetic axes, relative to the angular size of the polar cap region, partially determines the repetition rate and polarization properties of FRBs. We discuss how many of the properties of repeating FRBs - such as their lack of periodicity, energetics, small PA swing, spectro-temporal correlation and inferred low source density are explained by this model. The systematic PA swing and the periodic modulation of long duration bursts from non-repeaters are also natural outcomes. We derive a lower limit of about 400 on the Lorentz factor of FRB sources using this model for bursts with a linear polarization degree greater than 95%.

We revisit the Ultra-High-Energy Cosmic Ray (UHECRs) production in Tidal Disruption Events (TDEs) in the light of recent neutrino-TDE associations. We use an isotropically emitting source-propagation model, which has been developed to describe the neutrino production in AT2019dsg, AT2019fdr, and AT2019aalc. These TDEs have strong dust echoes in the infrared range, which are potentially linked with the neutrino production. A mechanism where neutrinos originate from cosmic ray scattering on infrared photons implies cosmic rays in the ultra-high energy range, thus suggesting a natural connection with the observed UHECR. We extrapolate the three TDE associations to a population of neutrino- and UHECR-emitting TDEs, and postulate that these TDEs power the UHECRs. We then infer the source composition, population parameters, and local rates that are needed to describe UHECR data. We find that UHECR data point towards a mix of light to mid-heavy injection isotopes, which could be found, e.g., in oxygen-neon-magnesium white dwarfs, and to a contribution of at least two groups of TDEs with different characteristics, dominated by AT2019aalc-type events. The required local TDE rates of ${\mathcal O}(10^2)~\mathrm{Gpc^{-3} \, yr^{-1}}$, however, are more indicative of the disruption of main sequence stars. We propose an enhanced efficiency in the acceleration of heavier nuclei that could address this discrepancy. The predicted diffuse neutrino fluxes suggest a population of astrophysical neutrino sources that can be observed by future radio neutrino detection experiments.

We present the first collisionless realization of black hole accretion consistent with a persistent magnetically arrested disk state. The accretion flow, consisting of an ion-electron disk plasma combined with magnetospheric pair creation effects, is simulated using first-principles general-relativistic particle-in-cell methods. The axisymmetric simulation is evolved over significant dynamical timescales during which a quasi-steady accretion state is reached with several magnetic flux eruption cycles. We include a realistic treatment of inverse Compton scattering and pair production, which allows for studying the interaction between the collisionless accretion flow and the pair-loaded jet. Our findings indicate that magnetic flux eruptions associated with equatorial magnetic reconnection within the black hole magnetosphere and the formation of spark gaps are locations of maximal particle acceleration. Flux eruptions, starting near the central black hole, can trigger Kelvin-Helmholtz-like vortices at the jet-disk interface that facilitate efficient mixing between disk and jet plasma. Transient periods of increased pair production following the magnetic flux eruptions and reconnection events are responsible for most of the highly accelerated particles.

Low-metallicity environments are subject to inefficient cooling. They also have low dust-to-gas ratios and therefore less efficient photoelectric (PE) heating than in solar-neighbourhood conditions, where PE heating is one of the most important heating processes in the warm neutral interstellar medium (ISM). We perform magneto-hydrodynamic simulations of stratified ISM patches with a gas metallicity of 0.02 Z$_\odot$ as part of the SILCC project. The simulations include non-equilibrium chemistry, heating, and cooling of the low-temperature ISM as well as anisotropic cosmic ray (CR) transport, and stellar tracks. We include stellar feedback in the form of far-UV and ionising (FUV and EUV) radiation, massive star winds, supernovae, and CR injection. From the local CR energy density, we compute a CR heating rate that is variable in space and time. In this way, we can compare the relative impact of PE and CR heating on the metal-poor ISM and find that CR heating can dominate over PE heating. Models with a uniform CR ionisation rate suppress or severely delay star formation, since they provide a larger amount of energy to the ISM due to CR heating. Models with a variable CR ionisation rate form stars predominantly in pristine regions with low PE heating and CR ionisation rates where the metal-poor gas is able to cool efficiently. Because of the low metallicity, the amount of formed stars in all runs is not enough to trigger outflows of gas from the mid-plane.

Blue large-amplitude pulsators (BLAPs) are a newly discovered group of compact pulsating stars whose origin needs to be explained. Of the existing evolutionary scenarios that could lead to the formation of BLAPs, there are two in which BLAPs are the products of the merger of two stars, either a main sequence star and a helium white dwarf or two low-mass helium white dwarfs. Among over a hundred known BLAPs, three equidistant in frequency modes had been found in one, OGLE-BLAP-001. We show that similar three equidistant in frequency modes exist in yet another BLAP, ZGP-BLAP-08. This perfect separation in frequency is a strong argument to explain the modes in terms of an oblique pulsator model. This model is supported by the character of the changes of the pulsation amplitude and phase with the rotational phase. Consequently, we hypothesize that these two BLAPs are magnetic, as equidistant in frequency pulsation modes should be observed in the presence of a magnetic field whose axis of symmetry does not coincide with the rotation axis. A logical consequence of this hypothesis is to postulate that these two BLAPs could have originated in a merger scenario, just how the origin of magnetic white dwarfs is explained. We also find that period changes in both stars cannot be interpreted by a constant rate of period change and discuss the possible origin of these changes.

Terrestrial exoplanets around M- and K-type stars are important targets for atmospheric characterisation. Such planets are likely tidally locked with the order of spin-orbit resonances (SORs) depending on eccentricity. We explore the impact of SORs on 3D atmospheric dynamics and chemistry, employing a 3D coupled Climate-Chemistry Model to simulate Proxima Centauri b in 1:1 and 3:2 SOR. For a 1:1 SOR, Proxima Centauri b is in the Rhines rotator circulation regime with dominant zonal gradients (global mean surface temperature 229 K). An eccentric 3:2 SOR warms Proxima Centauri b to 262 K with gradients in the meridional direction. We show how a complex interplay between stellar radiation, orbit, atmospheric circulation, and (photo)chemistry determines the 3D ozone distribution. Spatial variations in ozone column densities align with the temperature distribution and are driven by stratospheric circulation mechanisms. Proxima Centauri b in a 3:2 SOR demonstrates additional atmospheric variability, including daytime-nighttime cycles in water vapour of ${+}$55% to ${-}$34% and ozone ($\pm5.2$%) column densities and periastron-apoastron water vapour cycles of ${+}$17% to ${-}$10%. Synthetic emission spectra for the spectral range of the Large Interferometer For Exoplanets fluctuate by up to 36 ppm with orbital phase angle for a 1:1 SOR due to 3D spatial and temporal asymmetries. The homogeneous atmosphere for the 3:2 SOR results in relatively constant emission spectra and provides an observational discriminant from the 1:1 SOR. Our work emphasizes the importance of understanding the 3D nature of exoplanet atmospheres and associated spectral variations to determine habitability and interpret atmospheric spectra.

Neutron stars are not observed to spin faster than about half their breakup rate. This limiting rotational frequency may be related to the strength of their crusts. As a star spins up from accretion, centrifugal forces stress the crust. We perform finite-element simulations of rotating neutron stars and find that the crust fails at rotation rates about half the breakup rate. We argue that this crust failure is asymmetric and produces a significant ellipticity (fractional difference in moments of inertia). A rotating star, with this ellipticity, radiates gravitational waves that limit further spin up. These stars may be promising sources for LIGO / VIRGO and next generation gravitational wave detectors.

Nascent binaries (NBs) are binary systems with very low mass ratios, less than ~0.2, in which the more massive component is an O- or B-type main-sequence star, while the secondary is a star contracting onto the main sequence. NBs are of interest because they can help to understand the formation of small-mass ratio systems and shed light on the origin of low-mass X-ray binaries, millisecond pulsars and type Ia supernovae. In photometry, short-period NBs show a strong irradiation effect due to the large difference between the effective temperatures of the components and the strong irradiation of a cool secondary by a hot primary. In spectroscopy, they usually appear as single-lined spectroscopic binaries. In the present paper, we summarize the status of our knowledge of Galactic nascent binaries and characterize two new members of this group, c2 Sco and V390 Pup, for which photometric data were obtained by the BRIght Target Explorer (BRITE) nano-satellite mission.

We used attitude data from the Mars Ingenuity helicopter with a simple steady-state model to estimate windspeeds and directions at altitudes of 3 meters up to 24 meters, the first time winds at such altitudes have been probed on Mars. We compared our estimates to concurrent wind data at 1.5 m height from the meteorology package MEDA onboard the Mars 2020 Perseverance rover and to predictions from meteorological models. Wind directions inferred from the Ingenuity data agreed to within uncertainties with the directions measured by MEDA, when the latter were available, but deviated from model-predicted directions by as much as 180 deg in some cases. Also, the inferred windspeeds are often much higher than expected. For example, meteorological predictions tailored to the time and location of Ingenuity's 59th flight suggest Ingenuity should not have seen windspeeds above about 15 m/s, but we inferred speeds reaching nearly 25 m/s. By contrast, the 61st flight was at a similar time and season and showed weaker winds then the 59th flight, suggesting winds shaped by transient phenomena. For flights during which we have MEDA data to compare to, inferred windspeeds imply friction velocities exceeding 1 m/s and roughness lengths of more than 10 cm based on a boundary layer model that incorporates convective instability, which seem implausibly large. These results suggest Ingenuity was probing winds sensitive to aerodynamic conditions hundreds of meters upwind instead of the conditions very near Mars 2020, but they may also reflect a need for updated boundary layer wind models. An improved model for Ingenuity's aerodynamic response that includes the effects of transient winds may also modify our results. In any case, the work here provides a foundation for exploration of planetary boundary layers using drones and suggests important future avenues for research and development.

Ground-based gravitational-wave detectors like the Advanced LIGO, Advanced Virgo, and KAGRA experiments now regularly witness gravitational waves from compact binary mergers: the relativistic collisions of neutron stars and/or stellar-mass black holes. With hundreds of such events observed to date, gravitational-wave observations are enabling increasingly precise surveys of the demographics of merging compact binaries, including the distributions of their masses, rotation rates, and positions throughout the Universe. This article will provide an overview of our observational knowledge of the compact binary population, as it stands today. I will discuss, in turn, observations of binary black holes, binary neutron stars, and neutron star-black hole mergers, describing what is currently known (or not yet known) about these different gravitational-wave sources. I will highlight emerging classes of binaries that do not fall cleanly into any of these existing categories. And I will conclude by reviewing the methodology by which population analyses of gravitational-wave sources are performed.

In this work, we study the cosmological effects of a tower of warm dark matter states on the cosmic microwave background (CMB) and on large-scale structure (LSS). For concreteness, we consider the $N$naturalness model, which is a proposed mechanism to solve the Higgs hierarchy problem. In this framework, the sector of particles of the Standard Model is copied $N$ times where the Higgs mass-squared value is the only parameter that changes between sectors. The other sectors are similar to our own, except their particles are proportionally heavier and cooler compared to the Standard Model sector. Since each sector is extremely weakly coupled to other sectors, direct observations of the new particles are not expected. The addition of new photon-like species and new neutrino-like species, however, can be detected through the CMB and in LSS data. These additional neutrinos form a tower of states with increasing mass and decreasing temperature compared to the SM neutrinos. This tower causes a more gradual suppression of the matter power spectrum across different comoving wavenumbers than a single warm dark matter state would. We quantitatively explore these effects in the $N$naturalness model and compute the parameter space allowed by the Planck 2018, weak lensing, and Lyman-$\alpha$ datasets. Depending on the underlying parameters, Planck 2018 and weak lensing data can require $N$naturalness to be tuned at the $10\%$ level for Dirac neutrinos and at the $5\%$ level for Majorana neutrinos. The additional neutrino states are crucial in constraining the model, particularly through their suppression of the power spectrum at small scales. The inclusion of many warm dark matter species is computationally very challenging and we make detailed assessments of our approximations and comment on potential future improvements.

Aerosols are a ubiquitous feature of planetary atmospheres and leave clear spectral imprints in exoplanet spectra. Pre-JWST, exoplanet retrieval frameworks mostly adopted simple parametric approximations. With JWST, we now have access to mid-infrared wavelengths where aerosols have detectable composition-specific resonance features. Here, we implement new features into the open-source atmospheric retrieval code POSEIDON to account for the complex scattering, reflection, and absorption properties of Mie scattering aerosols. We provide an open-source database of these Mie scattering cross sections and optical properties. We also extend the radiative transfer and retrieval functionality in POSEIDON to include multiple scattering reflection and emission spectroscopy. We demonstrate these new retrieval capabilities on archival Hubble and Spitzer transmission and secondary eclipse spectra of the hot Jupiter HD 189733 b. We find that a high-altitude, low-density, thin slab composed of sub-micron particles is necessary to fit HD 189733 b's transmission spectrum, with multiple aerosol species providing a good fit. We additionally retrieve a sub-solar H$_2$O abundance, a sub-solar K abundance, and do not detect CO$_2$. Our joint thermal and reflection retrievals of HD 189733 b's secondary eclipse spectrum, however, finds no evidence of dayside aerosols, a sub-solar dayside H$_2$O abundance, enhanced CO$_2$, and slighty sub-solar alkali abundances. We additionally explore how retrieval model choices, such as cloud parameterization, aerosol species and properties, and thermal structure parameterization affect retrieved atmospheric properties. Upcoming JWST data for hot Jupiters like HD 189733 b will be well suited to enable deeper exploration of aerosol properties, allowing the formulation of a self-consistent, multi-dimensional picture of cloud formation processes.

We provide an overview of the isotopic signatures of presolar supernova grains, specifically focusing on 44Ti-containing grains with robustly inferred supernova origins and their implications for nucleosynthesis and mixing mechanisms in supernovae. Recent technique advancements have enabled the differentiation between radiogenic (from 44Ti decay) and nonradiogenic 44Ca excesses in presolar grains, made possible by enhanced spatial resolution of Ca-Ti isotope analyses with the Cameca NanoSIMS (Nano-scale Secondary Ion Mass Spectrometer) instrument. Within the context of presolar supernova grain data, we discuss (i) the production of 44Ti in supernovae and the impact of interstellar medium heterogeneities on the galactic chemical evolution of 44Ca/40Ca, (ii) the nucleosynthesis processes of neutron bursts and explosive H-burning in Type II supernovae, and (iii) challenges in identifying the progenitor supernovae for 54Cr-rich presolar nanospinel grains. Drawing on constraints and insights derived from presolar supernova grain data, we also provide an overview of our current understanding of the roles played by various supernova types - including Type II, Type Ia, and electron capture supernovae - in accounting for the diverse array of nucleosynthetic isotopic variations identified in bulk meteorites and meteoritic components. We briefly overview the potential mechanisms that have been proposed to explain these nucleosynthetic variations by describing the transport and distribution of presolar dust carriers in the protoplanetary disk. We highlight existing controversies in the interpretation of presolar grain data and meteoritic nucleosynthetic isotopic variations, while also outlining potential directions for future research.

The super star cluster NGC1569-B has recently been observed to have an extremely high [Ba/Fe]. We consider that the observed high [Ba/Fe] ($\sim$ 1.3) is due to the chemical enrichment of giant molecular clouds by either collapsars, neutron star mergers, or magneto-rotational supernovae, and thereby investigate which of the three polluters can best reproduce the observed [Ba/Fe]. Since it is found that collapsars can best reproduce such an extremely high Ba abundance, we numerically investigate the star cluster formation in NGC1569 using chemodynamical simulations of merging dwarf galaxies with chemical enrichment by collapsars. The principal results are as follows. First, a cluster of the same scale as NGC1569-B was found to match both the observed [Ba/Fe] and [Fe/H] values, the best cluster having [Ba/Fe]= 1.3 $\pm$ 0.2 and [Fe/H] = $-$0.7 $\pm$ 0.2. This simulation used a core-collapse supernova per collapsar rate of 70, a standard initial mass function and an initial metallicity of [Fe/H]=-1.5. Second, a prediction of the Eu abundance of NGC1569-B is made: [Eu/Fe]= 1.9 $\pm$ 0.2. These results are shown to be invariant under a change in the orbit parameters used for the merger. The need for a merger to promote the star formation that leads to the synthesis of the Ba and the star cluster formation is confirmed. Collapsars can not only better explain [Ba/Fe] but also be consistent with the observed star formation rate and stellar mass of the dwarf galaxy.

We propose that the ring structure found by the Event Horizon Telescope Collaboration (EHTC) as the black hole shadow of Sgr A*is an artifact by the bumpy PSF (Point Spread Function) of the EHT2017. The imaging using sparse u-v data requires detailed scrutiny of the PSF. The estimated shadow diameter (48.7 +- 7 muas) is equal to the spacing between the main beam and the first sidelobe of the PSF (49.09 muas), which immediately suggests a potential problem in the deconvolution of the PSF. We show that the ring image can be derived from non-ring simulated datasets (noise only; point source) with a narrow Field-of-View (FOV) and an assumed self-calibration suggesting the EHT2017's u-v coverage is insufficient for reliable imaging. The EHTC analysis, based on calibrations with assumptions about the source's size and properties, selected the final image by prioritizing appearance rate of the similar structure from a large imaging parameter space over data consistency. Our independent analysis with the conventional hybrid mapping reveals an elongated east-west structure, consistent with previous observations. We believe it to be more reliable than the EHTC image, due to half the residuals in normalized visibility amplitude. The eastern half is brighter, possibly due to a Doppler boost from the rapid rotating disk. We hypothesize our image shows a portion of the accretion disk about 2 to a few Rs away from the black hole, rotating with nearly 60 % of the speed of light viewed from an angle of 40 -45 degrees.

Earth is expected to have acquired a reduced proto-atmosphere enriched in H2 and CH4 through the accretion of building blocks that contain metallic Fe and/or the gravitational trapping of surrounding nebula gas. Such an early, wet, reduced atmosphere that covers a proto-ocean would then ultimately evolve toward oxidized chemical compositions through photochemical processes that involve reactions with H2O-derived oxidant radicals and the selective escape of hydrogen to space. During this time, atmospheric CH4 could be photochemically reprocessed to generate not only C-bearing oxides but also organics. However, the branching ratio between organic matter formation and oxidation remains unknown despite its significance on the abiotic chemical evolution of early Earth. Here, we show via numerical analyses that UV absorptions by gaseous hydrocarbons such as C2H2 and C3H4 significantly suppress H2O photolysis subsequent CH4 oxidation during the photochemical evolution of a wet proto-atmosphere enriched in H2 and CH4. As a result, nearly half of the initial CH4 converted to heavier organics along with the deposition of prebiotically essential molecules such as HCN and H2CO on the surface of a primordial ocean for a geological timescale order of 10-100 Myr. Our results suggest that the accumulation of organics and prebiotically important molecules in the proto-ocean could produce a soup enriched in various organics, which might have eventually led to the emergence of living organisms.

The stellar stripping of satellites in cluster haloes is understood to play an important role in the production of intracluster light. Increasingly, cosmological simulations have been utilised to investigate its origin and assembly. However, such simulations typically model individual galaxies at relatively coarse resolutions, raising concerns about their accuracy. Although there is a growing literature on the importance of numerical resolution for the accurate recovery of the mass loss rates of dark matter (DM) haloes, there has been no comparable investigation into the numerical resolution required to accurately recover stellar mass loss rates in galaxy clusters. Using N-body simulations of satellite galaxies orbiting in a cluster halo represented by a static external potential, we conduct a set of convergence tests in order to explore the role of numerical resolution and force softening length on stellar stripping efficiency. We consider a number of orbital configurations, satellite masses and satellite morphologies. We find that stellar mass resolution is of minor importance relative to DM resolution. Resolving the central regions of satellite DM halos is critical to accurately recover stellar mass loss rates. Poorly resolved DM haloes develop cored inner profiles and, if this core is of comparable size to the stellar component of the satellite galaxy, this leads to significant over-stripping. To prevent this, relatively high DM mass resolutions of around $m_{\rm DM}\sim10^{6}$ M$_{\odot}$, better than those achieved by many contemporary cosmological simulations, are necessary.

NGC 1052-DF2 and -DF4 are two ultra-diffuse galaxies that have been reported as deficient in dark matter and associated with the same galaxy group. Recent findings suggest that DF2 and DF4 are part of a large linear substructure of dwarf galaxies that could have been formed from a high-velocity head-on encounter of two gas-rich galaxies, known as a bullet dwarf collision. Based on new observations from the Hubble Space Telescope, combined with existing imaging from the u band to mid-infrared, we test the bullet dwarf scenario by studying the morphologies and stellar populations of the trail dwarfs. We find no significant morphological differences between the trail dwarfs and other dwarfs in the group, while for both populations, their photometric major axes unexpectedly align parallel with the trail. We find that the trail dwarfs have significantly older ages and higher metallicities than the comparison sample, supporting the distinctiveness of the trail. These observations provide key constraints for any formation model, and we argue that they are currently best explained by the bullet dwarf collision scenario, with additional strong tests anticipated with future observations.

We investigate the distribution and evolution of HI gas in different theoretical models, including hydro-dynamical simulations (Illustris-TNG and SIMBA), semi-analytic models (GAEA), and the empirical models ( NeutralUniverseMachine; NUM). By comparing model predictions for the HI mass function (HIMF), HI-halo and HI-stellar mass relations, conditional HI mass function (CHIMF) and the halo occupation distribution (HOD) of HI-selected galaxies, we find that all models show reasonable agreement with the observed HIMF at $z\sim0$, but the differences become much larger at higher redshifts of $z=1$ and $z=2$. The HIMF of NUM shows remarkable agreement with the observation at $z=1$, whereas other models predict much lower amplitudes of HIMF at the high-mass end. Comparisons of CHIMF distributions indicate that the HIMF is dominated by halos of $10< \log(M_{\rm vir}/M_\odot) <11$ and $11< \log(M_{\rm vir}/M_\odot)<12$ at the low- and high-mass ends, respectively. From the HI HODs of central galaxies, we find that TNG100 overpredicts the number of central galaxies with high $M_{\rm HI}$ in massive halos and GAEA shows a very strong depletion of HI gas in quenched centrals of massive halos. The main cause of the differences is the AGN feedback mechanisms implemented in different models.

The potential association of the globular cluster (GC) NGC 4147 with the Sagittarius (Sgr) dwarf spheroidal galaxy has been proposed due to their comparable locations and radial velocities. However, there are still debates about this connection. In this study, we use data from the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys to assess their association. We redetermine thefundamental parameters of NGC 4147 and find that the cluster is 11.0 Gyr old, has a metallicity of Z=0.0006, and is located 18.5 kpc from the Sun. We utilize the matched filter algorithm to identify extratidal structures in the surrounding sky of NGC 4147. The multiarmed tidal structures we find align more closely with the result of internal two-body relaxation processes within the cluster itself. The orientations of the dispersed tidal structures, the orbital direction of the cluster, and the mean orbital direction of Sgr do not show any apparent connection to each other. It seems to challenge the hypothesis of a common origin between the cluster and Sgr. To further investigate the association, we study the kinematics of NGC 4147 with the newly determined fundamental parameters. We find that the orbit, orbital energy, and angular momentum of NGC 4147 are not compatible with those of Sgr or its streams. This suggests that the cluster is not dynamically associated with Sgr. The morphology and dynamics of NGC 4147 are more consistent with it being a GC that formed with other origin rather than being accreted from the Sgr dwarf galaxy.

Recent observations of planetary atmospheres in HAT-P-32 b and HAT-P-67 b reveal extensive outflows reaching up to hundreds of planetary radii. The helium 1083 nm light curves for these planets, captured across their full orbits, show notable asymmetries: both planets display more pronounced pre-transit than post-transit absorptions, with HAT-P-67 b being the more extreme case of that geometry. Using three-dimensional (3D) hydrodynamic simulations, we identify key factors influencing the formation of a dense leading outflow stream and characterize its morphology. Our models suggest that such a geometry of escaped material is caused by a relatively cold outflow of high mass-loss rate, launched preferentially from the planet's day side. From the simulations we calculate synthetic He I 1083 nm spectra that show large absorption depths and irregular line profiles due to complex gas kinematics. We find that the measurements of the He I 1083 nm equivalent width and the velocity shift relative to the planet's rest frame, observed over a significant portion of the planet's orbital phase, can provide important constraints on the outflow properties and its interaction with the stellar wind.

We explore the joint weak lensing and galaxy clustering analysis from the photometric survey operated by the China Space Station Telescope (CSST), and study the strength of the cosmological constraints. We employ a high-resolution JiuTian-1G simulation to construct a partial-sky light cone to $z=3$ covering 100 deg$^2$, and obtain the CSST galaxy mock samples based on an improved semi-analytical model. We perform a multi-lens-plane algorithm to generate corresponding synthetic weak lensing maps and catalogs. Then we generate the mock data based on these catalogs considering the instrumental and observational effects of the CSST, and use the Markov Chain Monte Carlo (MCMC) method to perform the constraints. The covariance matrix includes non-Gaussian contributions and super-sample covariance terms, and the systematics from intrinsic alignments, galaxy bias, photometric redshift uncertainties, shear calibration, and non-linear effects are considered in the analysis. We find that, for the joint analysis of the CSST weak lensing and galaxy clustering surveys, the cosmological parameters can be constrained to a few percent or even less than one percent level. This indicates the CSST photometric survey is powerful for exploring the Universe.

Obtaining well-calibrated photometric redshift probability densities for galaxies without a spectroscopic measurement remains a challenge. Deep learning discriminative models, typically fed with multi-band galaxy images, can produce outputs that mimic probability densities and achieve state-of-the-art accuracy. However, such models may be affected by miscalibration that would result in discrepancies between the model outputs and the actual distributions of true redshifts. Our work develops a novel method called the Contrastive Learning and Adaptive KNN for Photometric Redshift (CLAP) that resolves this issue. It leverages supervised contrastive learning (SCL) and k-nearest neighbours (KNN) to construct and calibrate raw probability density estimates, and implements a refitting procedure to resume end-to-end discriminative models ready to produce final estimates for large-scale imaging data. The harmonic mean is adopted to combine an ensemble of estimates from multiple realisations for improving accuracy. Our experiments demonstrate that CLAP takes advantage of both deep learning and KNN, outperforming benchmark methods on the calibration of probability density estimates and retaining high accuracy and computational efficiency. With reference to CLAP, we point out that miscalibration is particularly sensitive to the method-induced excessive correlations among data instances in addition to the unaccounted-for epistemic uncertainties. Reducing the uncertainties may not guarantee the removal of miscalibration due to the presence of such excessive correlations, yet this is a problem for conventional deep learning methods rather than CLAP. These discussions underscore the robustness of CLAP for obtaining photometric redshift probability densities required by astrophysical and cosmological applications. This is the first paper in our series on CLAP.

Superluminal propagation is an intrinsic problem in the diffusion equation and has not been effectively addressed for a long time. In this work, a rigorous solution to this issue is obtained under the assumption that particles undergo a random flight process, where they move isotropically at a constant speed while experiencing random scatterings. We validate this solution by comparing it with comprehensive simulations of the random flight process and find that it significantly deviates from the solution derived from the Jüttner propagator. This solution is broadly applicable to various diffusion phenomena, such as cosmic-ray propagation. We emphasize that our rigorous solution is particularly crucial in scenarios involving burst-like particle injection, where previous phenomenological approaches to the superluminal diffusion problem may not yield accurate results.

The Hubble tension refers to the significant discrepancy in the Hubble constant $H_{0}$ obtained from two different measurement methods in cosmology. One method derives data from the Cosmic Microwave Background (CMB) observations by the Planck satellite, yielding a value of $67.4\pm{0.5} \ \mathrm{km\ s^{-1}} \mathrm{Mpc^{-1}} $, while the other method relies on direct measurements of Type Ia supernovae, producing a value $73.04\pm{1.04} \ \mathrm{km\ s^{-1}} \mathrm{Mpc^{-1}} $. This issue has persisted for several years. To theoretically explore potential solutions to this problem, this paper examines a model within the framework of Einstein-Cartan (EC) theory, where torsion is introduced with spin as the corresponding entity, allowing for the assumption $H = -\alpha \phi$. By employing the Markov Chain Monte Carlo (MCMC) algorithm and utilizing Cosmic Chronometers (CC) data, we impose parameter constraints on various parameters in the Friedmann equations, particularly focusing on the curvature density parameter $\Omega_k$, to assess whether the model remains stable under this assumption and whether the estimated parameters align more closely with either of the observational results. In conclusion, we find that the parameter constraints in the model incorporating torsion ($ H_0 = 67.6^{+2.1}_{-2.7} \ \mathrm{km\ s^{-1}\ Mpc^{-1}}$, obtained under the Big Bang Nucleosynthesis (BBN) constraint with $\Omega_{k}=0$; $ H_0 = 66.2^{+4.4}_{-2.9} \ \mathrm{km\ s^{-1}\ Mpc^{-1}}$, obtained under same constraint but set $\Omega_{k}$ as a free variable; $ H_0 = 68.8^{+2.9}_{-4.2} \ \mathrm{km\ s^{-1}\ Mpc^{-1}}$, obtained under the Planck constraint) are more consistent with the value derived from CMB data, favoring the lower $H_0$ value.

Massive black hole binaries are one of the important sources for the TianQin project. Our research has revealed that, for TianQin, the signal-to-noise ratio squared during the inspiral phase of massive black hole binaries exhibits a direct proportionality to the ratio of the observation duration to the time remaining until coalescence. This finding is expected to greatly simplify the estimation of detection capabilities for massive black hole binaries. In this paper, we demonstrated this relationship under both all-sky average and non-average conditions. The latter introduces only an additional term, which we refer to as the response factor. Although this term is not easily calculated analytically, we provide a simple estimation method with an error margin of within 2%.

Accurate estimation of photometric redshifts (photo-$z$s) is crucial for cosmological surveys. Various methods have been developed for this purpose, such as template fitting methods and machine learning techniques, each with its own applications, advantages, and limitations. In this study, we propose a new approach that utilizes a deep learning model based on Recurrent Neural Networks (RNN) with Long Short-Term Memory (LSTM) to predict photo-$z$. Unlike many existing machine learning models, our method requires only flux measurements from different observed filters as input. The model can automatically learn the complex relationships between the flux data across different wavelengths, eliminating the need for manually extracted or derived input features, thereby providing precise photo-$z$ estimates. The effectiveness of our proposed model is evaluated using simulated data from the Chinese Space Station Telescope (CSST) sourced from the Hubble Space Telescope Advanced Camera for Surveys (HST-ACS) and the COSMOS catalog, considering anticipated instrument effects of the future CSST. Results from experiments demonstrate that our LSTM model, compared to commonly used template fitting and machine learning approaches, requires minimal input parameters and achieves high precision in photo-$z$ estimation. For instance, when trained on the same dataset and provided only with photometric fluxes as input features, the proposed LSTM model yields one-third of the outliers $f_{out}$ observed with a Multi-Layer Perceptron Neural Network (MLP) model, while the normalized median absolute deviation $\rm \sigma_{NMAD}$ is only two-thirds that of the MLP model. This study presents a novel approach to accurately estimate photo-$z$s of galaxies using photometric data from large-scale survey projects.

We present systematic identifications of supergiants of M31/M33 based on massive LAMOST spectroscopic survey. Radial velocities of nearly 5000 photometrically selected M31/M33 supergiant candidates have been properly derived from the qualified spectra released in LAMOST DR10. By comparing their radial velocities with those predicted from the rotation curves of M31, as well as utilizing {\it Gaia} astrometric measurements to exclude foreground contaminations, 199 supergiant members in M31, including 168 `Rank1' and 31 `Rank2', have been successfully identified. This sample contains 62 blue supergiants (BSGs, all `Rank1'), 134 yellow supergiants (YSGs, 103 `Rank1' and 31 `Rank2') and 3 red supergiants (RSGs, all `Rank1'). For M33, we identify 84 supergiant members (56 `Rank1' and 28 `Rank2'), which includes 28 BSGs (all `Rank1'), 53 YSGs (25 `Rank1' and 28 `Rank2') and 3 RSGs (all `Rank1'). So far, this is one of the largest supergiant sample of M31/M33 with full optical wavelength coverage (3700 \textless $\lambda$ \textless 9100 Å). This sample is valuable for understanding the star formation and stellar evolution under different environments.

We study the abundance, radial distribution, and orbits of luminous satellites in simulations of Milky Way-mass dark halos in the $\Lambda$CDM cosmology. We follow the evolution of a halo from the Aquarius project and the formation of satellites with the GALFORM semi-analytic model of galaxy formation, in which gas cools radiatively into halos before reionization and in halos that exceed a redshift-dependent ``critical'' virial mass after that. Subhalos are prone to disruption in the tidal field of the main halo, with the number of surviving self-bound subhalos increasing with resolution. Even in the highest resolution simulation (Aq-L1, with particle mass $m_{\rm p}\sim10^3\, M_\odot$), a substantial number of subhalos are disrupted but their galaxies may survive as ``orphans''. Whether or not a satellite becomes an orphan depends primarily on its time of infall. When orphans are included, the simulations yield a converged satellite stellar mass function across different resolution levels. The total number of luminous satellites is sensitive to the assumed redshift of reionization, but the shape of the satellite stellar mass function is robust, peaking at the stellar mass ($\sim 10^3\, M_\odot$) of a halo just above the critical threshold. Most orphans are found in the central regions of the main halo and make up roughly half of all satellites in Aq-L1. When orphans are taken into account there is no need to populate subhalos below the critical mass with satellites to fit the radial distribution of Milky Way satellites, as had been argued in recent work. Our model predicts that orphans dominate the ultra-faint population and that many more satellites with small apocentric radii should be detected in upcoming deep wide-field surveys.

Aims. The locations of binary neutron star (BNS) mergers within their host galaxies encode the systemic kicks that these systems received in the supernova aftermath. We investigate how the galactic potential and the systemic kicks shape the offset distribution of BNS mergers with a case study of GW 170817 and its host NGC 4993. Methods. We derived dynamical constraints on the host potential from integral field spectroscopy with Jeans anisotropic modelling. We evolved the trajectories of synthetic BNSs from the BPASS code in the galactic potential, using two different kick prescriptions to investigate how the observed offsets might differentiate between these two possibilities. The simulation was repeated after swapping the host potential with that of a dwarf galaxy, to test the effect of the potential on the offsets. Results. The location of GW 170817 is entirely consistent with our predictions, regardless of large or small kicks, because the strong potential of NGC 4993 is only diagnostic of very large kicks. In galaxies of similar or greater mass, large offsets can constrain large kicks, while small offsets do not provide much information. In an old dwarf galaxy, on the other hand, small offsets can constrain small kicks, while large offsets would prevent host association.

Magnetic fields are considered to be key components of massive stars, with a far-reaching impact on their evolution and ultimate fate. A magnetic mechanism was suggested for the collimated explosion of massive stars, relevant for long-duration gamma-ray bursts, X-ray flashes, and asymmetric core collapse supernovae. However, the origin of the observed stable, globally organized magnetic fields in massive stars is still a matter of debate: it has been argued that they can be fossil, dynamo generated, or generated by strong binary interactions or merging events. Taking into account that multiplicity is a fundamental characteristic of massive stars, observational evidence is accumulating that the magnetism originates through interaction between the system components, both during the initial mass transfer or when the stellar cores merge.

While numerous planetary and asteroid satellites show evidence for non-trivial rotation states, none are as emblematic as Hyperion, which has long been held as the most striking example of chaotic spin-orbit evolution in the Solar System. Nevertheless, an analytically tractable theory of the full 3D spin-orbit dynamics of Hyperion has not been developed. We derive the Hamiltonian for a spinning axisymmetric satellite in the gravitational potential of a planet without assuming planar or principal axis rotation and without averaging over the spin period. Using this model, we demonstrate the emergence of resonances between the nutation and orbital frequencies that act as the primary drivers of the spin dynamics. This analysis reveals that, contrary to long-held belief, Hyperion is not tumbling chaotically. Instead, it lies near or in a nutation-orbit resonance that is first-order in eccentricity, allowing it to rotate quasi-regularly. The most reliable observations are consistent with either nonchaotic motion or chaos that is orders of magnitude smaller than originally claimed. A separate phenomenon, the so-called barrel instability, is shown to be related to a different set of nutation-orbit resonances that generalize the planar spin-orbit resonances. Finally, we show that changes in spin states over long timescales are best understood by considering chaotic diffusion of quasi-conserved quantities.

Recently, the LHAASO Collaboration presented the first very-high-energy gamma-ray catalog, containing 90 TeV sources. Among these sources, 1LHAASO J1929 +1846u* is located 0.3$^\circ$ west of SNR G54.1 +0.3 and it also lies inside a $+53 \, \text{km s}^{-1}$ cloud (the Western Cloud) which may be associate with SNR G54.1+0.3. Moreover, one of IceCube's HESE track events is found at 1.3$^\circ$ north of 1LHAASO J1929 +1846u*. SNR G54.1+0.3 is young, with a powerful PWN inside. The X-ray radiation from the regions of SNR shell and PWN can be distinguished clearly. The radio emission from the PWN region is also available. However, due to the low angular resolution, the gamma-ray emission at the SNR by Fermi, HESS and VERITAS are considered as point sources. In this work, we explore a scenario that SNR G54.1 +0.3 is indeed associated with the Western Cloud and we derive the emissions from the PWN, the SNR shell, and the nearby molecular cloud. Our results can explain the multi-messenger observations, indicating that 1LHAASO J1929 +1846u* might be the excellent candidate of Galactic PeVatron.

Recent advancements in ultra-stable ground-based high-resolution spectrographs have propelled ground-based astronomy to the forefront of exoplanet detection and characterisation. Retrieving accurate atmospheric parameters depends on accurate modelling and removal of the telluric contamination while preserving the faint underlying exoplanet signal. There exist many methods to model telluric contamination, whether directly modelling the Earth's transmission spectrum via radiative transfer modelling, or using a principal component analysis (PCA)-like reconstruction to fit the time-invariant features of a spectrum. We aimed to assess the efficacy of these various telluric removal methods in preserving the underlying exoplanetary spectra. We compared two of the most common telluric modelling and removal methods, molecfit and the PCA-like algorithm SysRem, using planetary transmission spectra injected into three high-resolution optical observations taken with ESPRESSO. These planetary signals were injected at orbital periods of P = 2 days and 12 days, resulting in differing changes in radial velocity during transit. We then retrieved various injected atmospheric model parameters in order to determine the efficacy of the telluric removal methods. For the close-in, high velocity injected signal, we found that SysRem performed better for species that are also present in the Earth's atmosphere across each of the datasets. As we moved to slower moving signals at larger orbital separations, for one of the three datasets, SysRem dampened the planetary H$_2$O signal. In contrast, the H$_2$O signal was preserved for the telluric modelling method, molecfit. However, this behaviour was not ubiquitous across all three of the injected datasets, with another dataset showing a more precise H$_2$O/Fe ratio when preprocessed with SysRem.

We investigate the effects of solar activity on the Auger Engineering Radio Array (AERA) data collected over 10 years. We report the observation of Solar Radio Burst signals in AERA data associated with intense solar flares accompanied by moderate and strong radio blackout levels recorded by the National Oceanic and Atmospheric Administration (NOAA). Additionally, although in a frequency range different from AERA, the increased level of X-ray and extreme ultraviolet radiation during periods of larger solar activity also impacts the AERA data in a twofold way: (i) causing the atmosphere to bounce terrestrial radio waves emitted by sources far from the AERA site or (ii) causing radio signals to become degraded or completely absorbed (radio blackout) if the solar radiation results in larger ionization of the upper or lower layers of the ionosphere, respectively. We describe the identification of both cases in AERA data with a remarkable correlation between the Maximum Usable Frequency (MUF), that represents the highest frequency that can be used for radio communication between two points located on the Earth, modulated by the solar cycle, and the broadband noise observed in the frequency range of 30-40 MHz.

Active Galactic Nuclei (AGN) are objects located in the heart of galaxies which emit powerful and complex radiation across the electromagnetic spectrum. Understanding AGN has become a topic of interest due to their importance in galactic evolution and their ability to act as a probe to the distant Universe. Within the next few years, wide-field surveys such as the Legacy Survey of Space and Time (LSST) at the Rubin Vera Observatory are expected to increase the number of known AGN to $\mathcal{O} (10^{7})$ and the number of strongly lensed AGN to $\mathcal{O} (10^{4})$. In this paper we introduce \texttt{Amoeba}: an AGN Model of Optical Emission Beyond steady-state Accretion discs. The goal of \texttt{Amoeba} is to provide a modular and flexible modelling environment for AGN, in which all components can interact with each other. Through this work we describe the framework for major AGN components to vary self-consistently and keep flux distributions to connect these components to spatial dependent processes. We model properties beyond traditional single-component models, such as the reverberation of the corona's bending power law power spectrum through the accretion disc and broad line region (BLR). We simulate obscuration by the dusty torus and differential magnification of the disc and BLR due to microlensing. These features are joined together to create some of the most realistic light curve simulations to date. \texttt{Amoeba} takes a step forward in AGN modelling by joining the accretion disc, BLR, torus, intrinsic signal, and microlensing into a coherent model.

A recent phenomenological study of radio emission from normal and millisecond pulsars by Karastergiou et al has lead these authors to state that they are unable to exclude a common physics process as the source although the rotation periods and magnetic fields of these two classes are very different. This has bearing on the nature of that source and it is the purpose the present Letter to explore this problem further, specifically for the ion-proton model and for all those models that assume electron-positron pair creation above the polar cap. The ion-proton model satisfies this commonality whereas pair creation does not. We mention briefly some consequences of these findings.

We present a strategy for estimating the mass per unit length along supercluster-scale filaments that are oriented across the sky, based on mock redshift surveys of 264 filaments from the Millennium simulation. In our fiducial scenario, we place each simulated filament at a distance of 300 Mpc, perpendicular to the line of sight, and calculate the redshift dispersion using galaxies with magnitudes r<19.5. Some regions are dynamically complicated in ways that interfere with finding a simple relationship between dispersion sigma and linear mass density mu. However, by examining individual overlapping segments along the filaments, we find a relationship that allows us to successfully predict log(mu) from log(sigma) with a scatter of about +/- 0.20 dex, for ~ 70% of the regions along filaments. This relationship is robust to changes in the distance to the filament if the physical segment length and the absolute magnitude for galaxy selection are held constant. The relationship between redshift dispersion and mass is similar to that obtained for a simple analytical model where filaments are dynamically relaxed, and we examine the possibility that the galaxies are indeed relaxed within the gravitational potential of the filament. We find that this is not the case; galaxy dynamics are strongly effected by infall to the filament and by orbits within groups and clusters

Although planets have been found orbiting binary systems, whether they can survive binary interactions is debated. While the tightest-orbit binaries should host the most dynamically stable and long-lived circumbinary planetary systems, they are also the systems that are expected to experience mass transfer, common envelope evolution, or stellar mergers. In this study, we explore the effect of stable non-conservative mass transfer on the dynamical evolution of circumbinary planets. We present a new script that seamlessly integrates binary evolution data from the 1D binary stellar evolution code MESA into the N-body simulation code REBOUND. This integration framework enables a comprehensive examination of the dynamical evolution of circumbinary planets orbiting mass-transferring binaries, while simultaneously accounting for the detailed stellar structure evolution. In addition, we introduce a recalibration method to mitigate numerical errors from updates of binary properties during the system's dynamical evolution. We construct a reference binary model in which a $2.21\, M_\odot$ star loses its hydrogen-rich envelope through non-conservative mass transfer to the $1.76\, M_\odot$ companion star, creating a $0.38\,M_\odot$ subdwarf. We find the tightest stable orbital separation for circumbinary planets to be $\simeq 2.5$ times the binary separation after mass transfer. Accounting for tides by using the interior stellar structure, we find that tidal effects become apparent after the rapid mass transfer phase and start to fade away during the latter stage of the slow mass transfer phase. Our research provides a new framework for exploring circumbinary planet dynamics in interacting binary systems.

Refracted Gravity (RG) is a a classical theory of gravity where a gravitational permittivity $ a monotonically-increasing function of the local density rho , is introduced in the Poisson equation to mimic the effect of dark matter at astrophysical scales. We use high precision spectroscopic data of two massive galaxy clusters, MACS J1206.2-0847 at redshift z=0.44, and Abell S1063 (RXC J2248.7-4431) at z=0.35, to determine the total gravitational potential in the context of RG and to constrain the three, supposedly universal, free parameters of this model. Using an upgraded version of the MG-MAMPOSSt algorithm, we perform a kinematic analysis which combines the velocity distribution of the cluster galaxies and the velocity dispersion profile of the stars within the Brightest Cluster Galaxy (BCG). The unprecedented dataset used has been obtained by an extensive spectroscopic campaign carried out with the VIMOS and MUSE spectrographs at the ESO VLT. We found that RG describes the kinematics of these two clusters as well as Newtonian gravity, although the latter is slightly preferred. However, (i) each cluster requires a different set of the three free RG parameters, and (ii) the two sets are inconsistent with other results in the literature at different scales. We discuss the limitation of the method used to constrain the RG parameters as well as possible systematic effects which can give rise to the observed tension, notably deviations from the spherical symmetry and from the dynamical equilibrium of the clusters.

We present a catalog of binary companions to $\delta$ Scuti stars, detected through phase modulations of their pulsations in TESS data. Pulsation timing has provided orbits for hundreds of pulsating stars in binaries from space-based photometry. We have applied this technique to $\delta$ Sct stars observed in the first four years of TESS Mission photometry. We searched the 2-min cadence light curves of 1161 short-period instability strip pulsators for variations in pulsation phase caused by the dynamical influence of an unseen companion. We discovered 53 new binaries and we present orbital parameters and mass functions for the 24 systems with solvable orbits. For the brightest star in our sample $\alpha$ Pictoris, we perform a joint fit of the pulsation timing and Hipparcos astrometry. We present the first orbit for the $\alpha$ Pictoris system, obtaining an orbital period of 1316$\pm$2 days and a mass for $\alpha$ Pic b of 1.05$\pm$0.05 M$_\odot$. We revisit pulsation timing binaries from Kepler with Gaia kinematics, finding four systems that are members of the Galatic thick disk or halo. This suggests that they have been rejuvenated by mass transfer, and their companions are now white dwarfs. Further follow up of these systems may yield valuable constraints of the galactic blue straggler population.