INAF - Osservatorio Astrofisico di Catania
California Institute of Technology logoCalifornia Institute of TechnologyUniversity of OsloUniversity of Cambridge logoUniversity of CambridgeUniversity of VictoriaChinese Academy of Sciences logoChinese Academy of SciencesUniversity of ZurichTel Aviv University logoTel Aviv UniversityUniversity of Oxford logoUniversity of OxfordUniversity of Science and Technology of China logoUniversity of Science and Technology of ChinaScuola Normale SuperioreUniversity of Copenhagen logoUniversity of CopenhagenUniversity of EdinburghThe University of Texas at Austin logoThe University of Texas at AustinINFN logoINFNETH Zürich logoETH ZürichYonsei UniversityUniversity of CreteKavli Institute for the Physics and Mathematics of the UniverseUniversität HeidelbergUniversity of Maryland logoUniversity of MarylandUniversidad Autónoma de MadridUniversité Paris-Saclay logoUniversité Paris-SaclayStockholm University logoStockholm UniversityUniversity of HelsinkiUniversity of Arizona logoUniversity of ArizonaUniversity of Western AustraliaUniversity of SheffieldPrinceton University logoPrinceton UniversityUniversity of GenevaUniversity of PortsmouthUniversity of IcelandUniversità di GenovaUniversidade do PortoUniversity of SussexINAFAix Marseille UniversityNiels Bohr InstituteUniversity of JyväskyläUniversity of PadovaJet Propulsion LaboratoryJagiellonian UniversityInstituto de Astrofísica de CanariasUniversity of the WitwatersrandUniversity of NottinghamEuropean Space AgencyUniversity of Cape TownSISSANicolaus Copernicus Astronomical CenterObservatoire de la Côte d’AzurUniversity of Hawai’iUniversity of KwaZulu-NatalLudwig-Maximilians-UniversitätLaboratoire d’Astrophysique de MarseilleINAF-Istituto di RadioastronomiaINAF – Osservatorio Astronomico di RomaInstitut de Física d’Altes Energies (IFAE)Laboratoire de Physique des 2 Infinis Irène Joliot-CurieOsservatorio Astronomico della Regione Autonoma Valle d’AostaINAF - Osservatorio Astrofisico di CataniaINAF - Osservatorio Astronomico di ArcetriInstitut d’Astrophysique SpatialeNASADTU SpaceThe Queen’s University of BelfastInstituto de Astrofísica e Ciências do Espaço, Universidade de LisboaIRAP, Université de Toulouse, CNRS, CNESETH, Institute for AstronomyINAF-IASF, BolognaCosmic Dawn Center(DAWN)Universit degli Studi di FerraraUniversit de ParisUniversit Claude Bernard Lyon 1Excellence Cluster ‘Origins’Universit de LyonUniversit di PisaIFCA-CSIC-UCINAF Osservatorio Astronomico di PadovaUniversit degli Studi di FirenzeUniversit de MontpellierUniversit degli Studi di Napoli Federico IIUniversit di Roma Tor VergataINAF Osservatorio di Astrofisica e Scienza dello Spazio di BolognaUniversit Di BolognaINAF ` Osservatorio Astronomico di TriesteUniversit degli Studi di Trieste
Verifying the fully kinematic nature of the cosmic microwave background (CMB) dipole is of fundamental importance in cosmology. In the standard cosmological model with the Friedman-Lemaitre-Robertson-Walker (FLRW) metric from the inflationary expansion the CMB dipole should be entirely kinematic. Any non-kinematic CMB dipole component would thus reflect the preinflationary structure of spacetime probing the extent of the FLRW applicability. Cosmic backgrounds from galaxies after the matter-radiation decoupling, should have kinematic dipole component identical in velocity with the CMB kinematic dipole. Comparing the two can lead to isolating the CMB non-kinematic dipole. It was recently proposed that such measurement can be done using the near-IR cosmic infrared background (CIB) measured with the currently operating Euclid telescope, and later with Roman. The proposed method reconstructs the resolved CIB, the Integrated Galaxy Light (IGL), from Euclid's Wide Survey and probes its dipole, with a kinematic component amplified over that of the CMB by the Compton-Getting effect. The amplification coupled with the extensive galaxy samples forming the IGL would determine the CIB dipole with an overwhelming signal/noise, isolating its direction to sub-degree accuracy. We develop details of the method for Euclid's Wide Survey in 4 bands spanning 0.6 to 2 mic. We isolate the systematic and other uncertainties and present methodologies to minimize them, after confining the sample to the magnitude range with negligible IGL/CIB dipole from galaxy clustering. These include the required star-galaxy separation, accounting for the extinction correction dipole using the method newly developed here achieving total separation, accounting for the Earth's orbital motion and other systematic effects. (Abridged)
We report the discovery of 164 compact (radius < 1 arcmin) radio rings using MeerKAT 1.3 GHz data from the SARAO MeerKAT Galactic Plane Survey (l=2-60deg, 252-358deg, |b|<1.5deg) and the Galactic Centre mosaic, from a search aimed at identifying previously uncatalogued radio sources. Within this sample, approximately 19 per cent of the rings contain a central point radio source. A multiwavelength analysis reveals a striking diversity: about 40 per cent of the rings enclose an isolated infrared point source, 50 per cent exhibit an extended counterpart in the mid- or far-infrared, and several are only detected in the radio band. We found that 17 per cent of the rings in the sample are positionally coincident (within 5 arcsec) with known entries in SIMBAD, including unclassified infrared sources, spiral galaxies, young stellar objects and long-period variable candidates. Based on these matches and exploiting ancillary multiwavelength data and catalogues, we explore several formation scenarios for the rings, such as HII regions, planetary nebulae, mass-loss relics from evolved massive stars, supernova remnants, nova shells, galaxies, galaxy cluster lenses and odd radio circles. Tentative classifications are proposed for nearly 60 per cent of the sample. These results highlight the potential of MeerKAT to uncover previously undetected compact radio structures and, particularly, recover missing Galactic radio-emitting objects.
The stellar Rossby number, a dimensionless parameter quantifying the influence of Coriolis forces on convective motions, plays a pivotal role in understanding magnetic stellar evolution. In this work, we explore the connection between the Rossby number and potential dynamo mechanisms in Sun-like stars, as well as its dependence on fundamental stellar properties. We present a novel, detailed asteroseismic calibration of the convective turnover time, incorporating for the first time Gaia photometry alongside surface gravity, effective temperature, and stellar metallicity. Our analysis employs an expanded sample of more than 150 stars, including targets from the Kepler LEGACY and KOI surveys, as well as more evolved stars observed by TESS and K2. This sample spans evolutionary stages from the main sequence to the early red giant branch (RGB), enabling a comprehensive investigation of Rossby number trends across stellar evolution.
We present TOI-2155 b, a high-mass transiting brown dwarf discovered using data from NASA's Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with ground-based radial velocity measurements from the Tillinghast Reflector Echelle Spectrograph (TRES). We also analyze ground-based follow-up photometric data from the Wendelstein Observatory (WST), Las Cumbres Observatory Global Telescope (LCOGT), and Wild Boar Remote Observatory (WBR). TOI-2155 b is a short-period brown dwarf with a period of 3.7246950 +0.0000029/-0.0000028 days. The radius and mass of TOI-2155 b are found to be 0.975 +/- 0.008 Jupiter radii and 81.1 +/- 1.1 Jupiter masses, respectively, corresponding to a density of 110 +/- 3 g/cm3. The effective temperature of the subgiant host star is estimated at 6085 +/- 78 K, which identifies it as an F-type star with a radius of 1.705 +0.066/-0.064 solar radii and a mass of 1.33 +/- 0.008 solar masses. With a mass close to the hydrogen-burning limit, TOI-2155 b occupies a high-mass regime in the brown dwarf mass-radius diagram, making it a valuable benchmark system for testing models of substellar structure and evolution.
The cosmic microwave background (CMB) experiments have reached an era of unprecedented precision and complexity. Aiming to detect the primordial B-mode polarization signal, these experiments will soon be equipped with 10410^{4} to 10510^{5} detectors. Consequently, future CMB missions will face the substantial challenge of efficiently processing vast amounts of raw data to produce the initial scientific outputs - the sky maps - within a reasonable time frame and with available computational resources. To address this, we introduce BrahMap, a new map-making framework that will be scalable across both CPU and GPU platforms. Implemented in C++ with a user-friendly Python interface for handling sparse linear systems, BrahMap employs advanced numerical analysis and high-performance computing techniques to maximize the use of super-computing infrastructure. This work features an overview of the BrahMap's capabilities and preliminary performance scaling results, with application to a generic CMB polarization experiment.
The third gaia data release (DR3) provides a wealth of new data products. The early part of the release, Gaia EDR3, already provided the astrometric and photometric data for nearly two billion sources. The full release now adds improved parameters compared to Gaia DR2 for radial velocities, astrophysical parameters, variability information, light curves, and orbits for Solar System objects. The improvements are in terms of the number of sources, the variety of parameter information, precision, and accuracy. For the first time, Gaia DR3 also provides a sample of spectrophotometry and spectra obtained with the Radial Velocity Spectrometer, binary star solutions, and a characterisation of extragalactic object candidates. Before the publication of the catalogue, these data have undergone a dedicated transversal validation process. The aim of this paper is to highlight limitations of the data that were found during this process and to provide recommendations for the usage of the catalogue. The validation was obtained through a statistical analysis of the data, a confirmation of the internal consistency of different products, and a comparison of the values to external data or models. Gaia DR3 is a new major step forward in terms of the number, diversity, precision, and accuracy of the Gaia products. As always in such a large and complex catalogue, however, issues and limitations have also been found. Detailed examples of the scientific quality of the Gaia DR3 release can be found in the accompanying data-processing papers as well as in the performance verification papers. Here we focus only on the caveats that the user should be aware of to scientifically exploit the data.
A common feature of regular black hole spacetimes is the presence of an inner Cauchy horizon. The analogy to the Reissner-Nordström solution then suggests that these geometries suffer from a mass-inflation effect, rendering the Cauchy horizon unstable. Recently, it was shown that this analogy fails for certain classes of regular black holes, including the Hayward solution, where the late-time behavior of the mass function no longer grows exponentially but follows a power law. In this work, we extend these results in a two-fold way. First, we determine the basin-of-attraction for the power-law attractor, showing that the tamed growth of the mass function is generic. Second, we extend the systematic analysis to the Bardeen geometry, the Dymnikova black hole, and a spacetime arising from a non-singular collapse model newly proposed in the context of asymptotically safe quantum gravity. Remarkably, in the latter solution, the Misner-Sharp mass at the Cauchy horizon remains of the same order of magnitude of the mass of the black hole, since its growth is just logarithmic.
Gravitational waves from black-hole merging events have revealed a population of extra-galactic BHs residing in short-period binaries with masses that are higher than expected based on most stellar evolution models - and also higher than known stellar-origin black holes in our Galaxy. It has been proposed that those high-mass BHs are the remnants of massive metal-poor stars. Gaia astrometry is expected to uncover many Galactic wide-binary systems containing dormant BHs, which may not have been detected before. The study of this population will provide new information on the BH-mass distribution in binaries and shed light on their formation mechanisms and progenitors. As part of the validation efforts in preparation for the fourth Gaia data release (DR4), we analysed the preliminary astrometric binary solutions, obtained by the Gaia Non-Single Star pipeline, to verify their significance and to minimise false-detection rates in high-mass-function orbital solutions. The astrometric binary solution of one source, Gaia BH3, implies the presence of a 32.70 \pm 0.82 M\odot BH in a binary system with a period of 11.6 yr. Gaia radial velocities independently validate the astrometric orbit. Broad-band photometric and spectroscopic data show that the visible component is an old, very metal-poor giant of the Galactic halo, at a distance of 590 pc. The BH in the Gaia BH3 system is more massive than any other Galactic stellar-origin BH known thus far. The low metallicity of the star companion supports the scenario that metal-poor massive stars are progenitors of the high-mass BHs detected by gravitational-wave telescopes. The Galactic orbit of the system and its metallicity indicate that it might belong to the Sequoia halo substructure. Alternatively, and more plausibly, it could belong to the ED-2 stream, which likely originated from a globular cluster that had been disrupted by the Milky Way.
ETH Zurich logoETH ZurichUniversity of Washington logoUniversity of WashingtonCalifornia Institute of Technology logoCalifornia Institute of TechnologyUniversity of OsloUniversity of Cambridge logoUniversity of CambridgeUniversity of ZurichUniversity of BernFreie Universität BerlinKeele UniversityInstitute for Advanced StudyUniversity of Southern QueenslandStockholm University logoStockholm UniversityUniversity of BolognaMIT logoMITPrinceton University logoPrinceton UniversityUniversity of GenevaUniversity of ViennaUniversity of Warwick logoUniversity of WarwickUniversity of LeicesterUniversity of St Andrews logoUniversity of St AndrewsUniversity of IcelandTechnische Universität BerlinChalmers University of Technology logoChalmers University of TechnologyUniversité Côte d’AzurUniversity of GrazInstituto de Astrofísica e Ciências do EspaçoNiels Bohr InstituteLund UniversityInstituto de Astrofísica de CanariasGerman Aerospace Center (DLR)Universidad de La LagunaELTE Eötvös Loránd UniversitySETI InstituteEuropean Space Research and Technology CentreMax Planck Institute for AstronomyUniversity of PortoInstitut d'Astrophysique de ParisUniversity of PaduaINAF - Osservatorio Astrofisico di CataniaCaltech-IPACNational Aeronautics and Space AdministrationSpace Research InstituteF.R.S.-FNRSUniversidad Católica del NorteEuropean Space Agency (ESA)Konkoly ObservatoryCentro de Astrobiología (CSIC-INTA)Institut de Mécanique Céleste et de Calcul des ÉphéméridesSTAR Institute, Université de LiègeUniversit Grenoble AlpesNASA, Ames Research CenterAix-Marseille Universit",Universit Paris CitInstitute for Astronomy Astrophysics Space Applications and Remote SensingINAF Osservatorio Astronomico di PadovaCenter for Astrophysics  Harvard & Smithsonian
We present the discovery and characterization of two warm mini-Neptunes transiting the K3V star TOI-815 in a K-M binary system. Analysis of the spectra and rotation period reveal it to be a young star with an age of 200200+400200^{+400}_{-200}Myr. TOI-815b has a 11.2-day period and a radius of 2.94±\pm0.05R\it{R_{\rm\mathrm{\oplus}}} with transits observed by TESS, CHEOPS, ASTEP, and LCOGT. The outer planet, TOI-815c, has a radius of 2.62±\pm0.10R\it{R_{\rm\mathrm{\oplus}}}, based on observations of three non-consecutive transits with TESS, while targeted CHEOPS photometry and radial velocity follow-up with ESPRESSO were required to confirm the 35-day period. ESPRESSO confirmed the planetary nature of both planets and measured masses of 7.6±\pm1.5 M\it{M_{\rm \mathrm{\oplus}}} (ρP\rho_\mathrm{P}=1.640.31+0.33^{+0.33}_{-0.31}gcm3^{-3}) and 23.5±\pm2.4M\it{M_{\rm\mathrm{\oplus}}} (ρP\rho_\mathrm{P}=7.21.0+1.1^{+1.1}_{-1.0}gcm3^{-3}) respectively. Thus, the planets have very different masses, unlike the usual similarity of masses in compact multi-planet systems. Moreover, our statistical analysis of mini-Neptunes orbiting FGK stars suggests that weakly irradiated planets tend to have higher bulk densities compared to those suffering strong irradiation. This could be ascribed to their cooler atmospheres, which are more compressed and denser. Internal structure modeling of TOI-815b suggests it likely has a H-He atmosphere constituting a few percent of the total planet mass, or higher if the planet is assumed to have no water. In contrast, the measured mass and radius of TOI-815c can be explained without invoking any atmosphere, challenging planetary formation theories. Finally, we infer from our measurements that the star is viewed close to pole-on, which implies a spin-orbit misalignment at the 3σ\sigma level.
We present a detailed analysis of HARPS-N radial velocity observations of K2-100, a young and active star in the Praesepe cluster, which hosts a transiting planet with a period of 1.7 days. We model the activity-induced radial velocity variations of the host star with a multi-dimensional Gaussian Process framework and detect a planetary signal of 10.6±3.0ms110.6 \pm 3.0 {\rm m\,s^{-1}}, which matches the transit ephemeris, and translates to a planet mass of 21.8±6.2M21.8 \pm 6.2 M_\oplus. We perform a suite of validation tests to confirm that our detected signal is genuine. This is the first mass measurement for a transiting planet in a young open cluster. The relatively low density of the planet, 2.040.61+0.66gcm32.04^{+0.66}_{-0.61} {\rm g\,cm^{-3}}, implies that K2-100b retains a significant volatile envelope. We estimate that the planet is losing its atmosphere at a rate of 10111012gs110^{11}-10^{12}\,{\rm g\,s^{-1}} due to the high level of radiation it receives from its host star.
ETH Zurich logoETH ZurichCNRS logoCNRSUniversity of Cambridge logoUniversity of CambridgeTel Aviv University logoTel Aviv UniversityUniversity College London logoUniversity College LondonUniversity of EdinburghUniversidade de LisboaTechnische Universität DresdenKU Leuven logoKU LeuvenRadboud UniversityUniversität HeidelbergUniversity of HelsinkiUppsala UniversityUniversity of Arizona logoUniversity of ArizonaSorbonne Université logoSorbonne UniversitéLeiden University logoLeiden UniversityUniversity of GenevaUniversity of ViennaUniversitat de BarcelonaUniversity of LeicesterObservatoire de ParisUniversité de LiègeINAF - Osservatorio Astrofisico di TorinoUniversité Côte d’AzurUniversity of Groningen logoUniversity of GroningenClemson UniversityLund UniversityUniversidad Nacional Autónoma de MéxicoSwinburne University of TechnologyUniversität HamburgThales Alenia SpaceEuropean Southern Observatory logoEuropean Southern ObservatoryLaboratoire d’Astrophysique de BordeauxSISSACNESUniversity of CalgaryUniversidad de La LagunaIMT AtlantiqueObservatoire de la Côte d’AzurEuropean Space Astronomy Centre (ESAC)Kapteyn Astronomical InstituteObservatoire astronomique de StrasbourgNational Observatory of AthensQueen's University BelfastUniversidade de Santiago de CompostelaINAF – Osservatorio Astronomico di RomaInstituto de Astrofísica de Canarias (IAC)Universidade da CoruñaINAF – Osservatorio Astronomico d’AbruzzoSRON Netherlands Institute for Space ResearchINAF - Osservatorio Astrofisico di CataniaUniversidade de VigoRoyal Observatory of BelgiumINAF- Osservatorio Astronomico di CagliariLeibniz-Institut für Astrophysik Potsdam (AIP)F.R.S.-FNRSTelespazio FRANCEAirbus Defence and SpaceInstituto Galego de Física de Altas Enerxías (IGFAE)Universitat Politècnica de Catalunya-BarcelonaTechSTAR InstituteEuropean Space Agency (ESA)Lund ObservatoryGeneva University HospitalLeiden ObservatoryFinnish Geospatial Research Institute FGICGIAgenzia Spaziale Italiana (ASI)Mullard Space Science LaboratoryInstitut de Ciències del Cosmos (ICCUB)Aurora TechnologyCentro de Supercomputación de Galicia (CESGA)Institut UTINAMGEPISERCOInstitut d’Astronomie et d’AstrophysiqueGMV Innovating Solutions S.L.Space Science Data Center (SSDC)Wallonia Space Centre (CSW)Indra Sistemas S.A.Universit PSL* National and Kapodistrian University of AthensUniversit de ToulouseUniversit Bourgogne Franche-ComtUniversit Libre de BruxellesIstituto Nazionale di Fisica Nucleare INFNMax Planck Institut fr AstronomieUniversit de LorraineUniversit de BordeauxUniversit de StrasbourgUniversit di PadovaINAF Osservatorio Astrofisico di ArcetriINAF Osservatorio Astronomico di PadovaAstronomisches Rechen–InstitutINAF Osservatorio di Astrofisica e Scienza dello Spazio di Bologna
We produce a clean and well-characterised catalogue of objects within 100\,pc of the Sun from the \G\ Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use. The selection of objects within 100\,pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100\,pc is included in the catalogue. We have produced a catalogue of \NFINAL\ objects that we estimate contains at least 92\% of stars of stellar type M9 within 100\,pc of the Sun. We estimate that 9\% of the stars in this catalogue probably lie outside 100\,pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of \G\ Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10\,pc of the Sun.
PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 sec readout cadence and 2 with 2.5 sec candence) providing a wide field-of-view (2232 deg2) and a large photometric magnitude range (4-16 mag). It focusses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2%, 4-10% and 10% for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50% of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0.
We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251°l\le l \le 358°and 2°l\le l \le 61°at b1.5°|b| \le 1.5°). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8" and a broadband RMS sensitivity of \sim10--20 μ\mu Jy/beam. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908--1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE HII region candidates are not true HII regions; and a large sample of previously undiscovered background HI galaxies in the Zone of Avoidance.
In the third APOKASC catalog, we present data for the complete sample of 15,808 evolved stars with APOGEE spectroscopic parameters and Kepler asteroseismology. We used ten independent asteroseismic analysis techniques and anchor our system on fundamental radii derived from Gaia LL and spectroscopic TeffT_{\rm eff}. We provide evolutionary state, asteroseismic surface gravity, mass, radius, age, and the spectroscopic and asteroseismic measurements used to derive them for 12,418 stars. This includes 10,036 exceptionally precise measurements, with median fractional uncertainties in \nmax, \dnu, mass, radius and age of 0.6\%, 0.6\%, 3.8\%, 1.8\%, and 11.1\% respectively. We provide more limited data for 1,624 additional stars which either have lower quality data or are outside of our primary calibration domain. Using lower red giant branch (RGB) stars, we find a median age for the chemical thick disk of 9.14±0.05(ran)±0.9(sys)9.14 \pm 0.05 ({\rm ran}) \pm 0.9 ({\rm sys}) Gyr with an age dispersion of 1.1 Gyr, consistent with our error model. We calibrate our red clump (RC) mass loss to derive an age consistent with the lower RGB and provide asymptotic GB and RGB ages for luminous stars. We also find a sharp upper age boundary in the chemical thin disk. We find that scaling relations are precise and accurate on the lower RGB and RC, but they become more model dependent for more luminous giants and break down at the tip of the RGB. We recommend the usage of multiple methods, calibration to a fundamental scale, and the usage of stellar models to interpret frequency spacings.
Magnetic fields play a crucial role in planetary evolution and habitability. While the intrinsic magnetic fields of solar system planets are relatively well understood, the magnetic properties of exoplanets remain largely unconstrained, despite their potential ubiquity. Detecting exoplanetary magnetic fields is essential to advancing our understanding of planetary habitability beyond the solar system. This paper focuses on two promising spectropolarimetric techniques for detecting magnetic fields in hot exoplanets: direct detection through polarization signatures in the He I 1083 nm triplet and indirect detection via star-planet magnetic interactions manifesting as stellar hot spots. The direct method is particularly suited to close-in gas giants, leveraging the Hanle and Zeeman effects to detect low-amplitude magnetic fields. The indirect method can apply to both giant and low-mass planets by identifying magnetic connectivity-induced features in the stellar atmosphere. Although the interpretation of current detections remain tentative, upcoming high-resolution spectropolarimetric capabilities in the UV and near-infrared, particularly with future missions like HWO, promise to enable definitive measurements of exoplanetary magnetic fields. These advancements will open new avenues for probing the magnetic environments of exoplanets and their implications for atmospheric retention and habitability.
Context. As part of Gaia Data Release 3 (Gaia DR3), epoch photometry has been released for 1.2 million sources centred on M31. This is a taster for Gaia Data Release 4 where all the epoch photometry will be released. Aims. In this paper the content of the Gaia Andromeda Photometric Survey is described, including statistics to assess the quality of the data. Known issues with the photometry are also outlined. Methods. Methods are given to improve interpretation of the photometry, in particular, a method for error renormalization. Also, use of correlations between the three photometric passbands allows clearer identification of variables that is not affected by false detections caused by systematic effects. Results. The Gaia Andromeda Photometric Survey presents a unique opportunity to look at Gaia epoch photometry that has not been preselected due to variability. This allows investigations to be carried out that can be applied to the rest of the sky using the mean source results. Additionally scientific studies of variability can be carried out on M31 and the Milky Way in general.
We present the final data release of the Kilo-Degree Survey (KiDS-DR5), a public European Southern Observatory (ESO) wide-field imaging survey optimised for weak gravitational lensing studies. We combined matched-depth multi-wavelength observations from the VLT Survey Telescope and the VISTA Kilo-degree INfrared Galaxy (VIKING) survey to create a nine-band optical-to-near-infrared survey spanning 13471347 deg2^2. The median rr-band 5σ5\sigma limiting magnitude is 24.8 with median seeing 0.70.7^{\prime\prime}. The main survey footprint includes 44 deg2^2 of overlap with existing deep spectroscopic surveys. We complemented these data in DR5 with a targeted campaign to secure an additional 2323 deg2^2 of KiDS- and VIKING-like imaging over a range of additional deep spectroscopic survey fields. From these fields, we extracted a catalogue of 126085126\,085 sources with both spectroscopic and photometric redshift information, which enables the robust calibration of photometric redshifts across the full survey footprint. In comparison to previous releases, DR5 represents a 34%34\% areal extension and includes an ii-band re-observation of the full footprint, thereby increasing the effective ii-band depth by 0.40.4 magnitudes and enabling multi-epoch science. Our processed nine-band imaging, single- and multi-band catalogues with masks, and homogenised photometry and photometric redshifts can be accessed through the ESO Archive Science Portal.
Exoplanet searches through space-based photometric time series have shown to be very efficient in recent years. However, follow-up efforts on the detected planet candidates have been demonstrated to be critical to uncover the true nature of the transiting objects. In this paper we show a detailed analysis of one of those false positives hidden as planetary signals. In this case, the candidate KOI-3886.01 showed clear evidence of a planetary nature from various techniques. Indeed, the properties of the fake planet set it among the most interesting and promising for the study of planetary evolution as the star leaves the main sequence. To unveil the true nature of this system, we present a complete set of observational techniques including high-spatial resolution imaging, high-precision photometric time series (showing eclipses, phase curve variations and asteroseismology signals), high-resolution spectroscopy and derived radial velocities, to unveil the true nature of this planet candidate. We find that KOI-3886.01 is an interesting false positive case: a hierarchical triple system composed by a \simK2III giant star (KOI-3886A) accompanied by a close-in eclipsing binary formed by a subgiant \simG4IV star (KOI-3886B) and a brown dwarf (KOI-3886C). In particular, KOI-3886C is one of the most irradiated brown dwarfs known to date, showing the largest radius in this substellar regime. It is also the first eclipsing brown dwarf known around an evolved star. In this paper we highlight the relevance of complete sets of follow-up observations to extrasolar planets detected by the transit technique using large-pixel photometers such as Kepler and TESS, and in the future, PLATO. In particular, multi-color high-spatial resolution imaging was the first hint toward ruling out the planet scenario in this system.
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PLATO (PLAnetary Transits and Oscillations of stars) is ESA's M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large number of stars. PLATO will detect small planets (down to <2 R_(Earth)) around bright stars (<11 mag), including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observations from the ground, planets will be characterised for their radius, mass, and age with high accuracy (5 %, 10 %, 10 % for an Earth-Sun combination respectively). PLATO will provide us with a large-scale catalogue of well-characterised small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. It will make possible comparative exoplanetology to place our Solar System planets in a broader context. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements. Here we review the science objectives, present PLATO's target samples and fields, provide an overview of expected core science performance as well as a description of the instrument and the mission profile at the beginning of the serial production of the flight cameras. PLATO is scheduled for a launch date end 2026. This overview therefore provides a summary of the mission to the community in preparation of the upcoming operational phases.
We present an empirical model of age-dependent photospheric lithium depletion, calibrated using a large, homogeneously-analysed sample of 6200 stars in 52 open clusters, with ages from 2--6000 Myr and $-0.3<{\rm [Fe/H}]<0.2$, observed in the Gaia-ESO spectroscopic survey. The model is used to obtain age estimates and posterior age probability distributions from measurements of the Li I 6708A equivalent width for individual (pre) main sequence stars with 3000 &lt; T_{\rm eff}/{\rm K} &lt;6500, a domain where age determination from the HR diagram is either insensitive or highly model-dependent. In the best cases, precisions of 0.1 dex in log age are achievable; even higher precision can be obtained for coeval groups and associations where the individual age probabilities of their members can be combined. The method is validated on a sample of exoplanet-hosting young stars, finding agreement with claimed young ages for some, but not others. We obtain better than 10 per cent precision in age, and excellent agreement with published ages, for seven well-studied young moving groups. The derived ages for young clusters (&lt;1 Gyr) in our sample are also in good agreement with their training ages, and consistent with several published, model-insensitive lithium depletion boundary ages. For older clusters there remain systematic age errors that could be as large as a factor of two. There is no evidence to link these errors to any strong systematic metallicity dependence of (pre) main sequence lithium depletion, at least in the range $-0.29 < {\rm [Fe/H]} < 0.18$. Our methods and model are provided as software -- "Empirical AGes from Lithium Equivalent widthS" (EAGLES).
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