Astronomy & Astrophysics最新文献

{"title":"Comment on Ádám et al. (2023) : Large fraction of already known systems reported","authors":"P. Zasche","doi":"10.1051/0004-6361/202450463","DOIUrl":"https://doi.org/10.1051/0004-6361/202450463","url":null,"abstract":"In this work, I report that large fraction of stars detected by A A, 674,\u0000A170 2023A&A...674A.170A and noted in that work as new discoveries are in fact known systems.\u0000This is especially true for the dense bulge fields with large blending of nearby sources. Among\u0000the published 245 stars determined to be doubly eclipsing (i.e. containing two eclipsing signals),\u0000I identified 53 blends. In other words, about a quarter of the systems noted by 2023A&A...674A.170A are not actually doubly eclipsing; rather, these are\u0000contaminations of known nearby sources that have already been detected by OGLE. Such a high\u0000proportion of reported false positives should not be readily ignored and ought to be addressed in\u0000future studies.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"4 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Double periodic variable V4142 Sgr: A key to approaching the stellar dynamo","authors":"J. Rosales, J. Petrovic, R. Mennickent, D. R. G. Schleicher, G. Djurašević, N. W. C. Leigh","doi":"10.1051/0004-6361/202348290","DOIUrl":"https://doi.org/10.1051/0004-6361/202348290","url":null,"abstract":"In this work we focus on the double periodic variable (DPV) star V4142,Sgr, aiming to provide a deeper understanding of its evolution, the formation of its accretion disk, and the operation of magnetic dynamos within the donor star. We analyze its characteristics in detail as well as the phenomena associated with DPV stars more generally. The model was implemented using the stellar evolution code MESA r22.11.1. The modeling process starts from the zero age main sequence and incorporates differential rotation to facilitate the creation of a stellar dynamo in the donor star. We adjusted the model by employing a chi-square algorithm, minimizing the deviation between theoretical and observed values based on previously published fundamental parameters for this system. Our analysis includes an evaluation of various parameters, such as initial masses, orbital periods, mixing parameters, the thermohaline parameter, and metallicities. We assessed the algorithm convergence and set the stopping criterion at 20 helium core depletion in the donor star. A comprehensive analysis was conducted at each evolutionary stage, utilizing the Tayler-Spruit formalism to understand the mechanism of magnetic dynamos. The model begins by adjusting fundamental parameters published for this system through a chi-squared optimization algorithm, adopting an initial orbital period of 15.0 days and initial masses for the donor and gainer star of $ M_ i,d odot $ and $ M_ i,g odot $, with a metallicity associated with this type of DPV of $ Z = 0.02 $. It successfully converges with six degrees of freedom and 5 confidence, resulting in a chi-squared value of 0.007. In addition, the best-fit model for V4142,Sgr shows it is in thermal-timescale mass transfer. Our analysis provides insights into the role of differential rotation in facilitating the formation of a stellar dynamo. Additionally, we have determined that our type-B gainer star is located in a region similar to other type-B DPVs that have undergone rejuvenation due to the transfer of matter. The size of the gainer star shrinks considerably, but it rejuvenates thanks to the material acquired from its donor companion. As for the donor star, the creation and amplification of magnetic fields are influenced by the mixing diffusivity, $ D_ ST $, which is activated by advection outside the overshooting zone.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"3 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 581 multi-planetary system with new Doppler measurements from CARMENES, HARPS, and HIRES","authors":"A. von Stauffenberg, T. Trifonov, A. Quirrenbach, S. Reffert, A. Kaminski, S. Dreizler, I. Ribas, A. Reiners, M. Kürster, J. Twicken, D. Rapetti, J. A. Caballero, P. Amado, S. V. J. Béjar, C. Cifuentes, S. Góngora, A. Hatzes, T. Henning, D. Montes, J. C. Morales, A. Schweitzer","doi":"10.1051/0004-6361/202449375","DOIUrl":"https://doi.org/10.1051/0004-6361/202449375","url":null,"abstract":"GJ,581 is a nearby M dwarf known to host a packed multiple planet system composed of two super-Earths and a Neptune-mass planet. We present new orbital analyses of the GJ,581 system, utilizing recent radial velocity (RV) data obtained from the CARMENES spectrograph combined with newly reprocessed archival data from the HARPS and HIRES spectrographs. Our aim was to analyze the post-discovery spectroscopic data of GJ,581, which were obtained with CARMENES. In addition, we used publicly available HIRES and HARPS spectroscopic data to seek evidence of the known and disputed exoplanets in this system. We aimed to investigate the stellar activity of GJ,581 and update the planetary system's orbital parameters using state-of-the-art numerical models and techniques. We performed a periodogram analysis of the available precise CARMENES, HIRES, and HARPS RVs and of stellar activity indicators. We conducted detailed orbital analyses by testing various orbital configurations consistent with the RV data. We studied the posterior probability distribution of the \u0000 parameters fit to the data and we explored the long-term stability and overall orbital dynamics of \u0000 the GJ,581 system. We refined the orbital parameters of the GJ,581 system using the most precise and complete set of Doppler data available. Consistent with the existing literature, our analysis confirms that the system is unequivocally composed of only three planets detectable in the present data, dismissing the putative planet GJ,581,d as an artifact of stellar activity. Our N-body fit reveals that the system's inclination is $i = $,deg, which implies that the planets could be up to 30 more massive than their previously reported minimum masses. Furthermore, we report that the GJ,581 system exhibits long-term stability, as indicated by the posterior probability distribution, characterized by secular dynamical interactions without the involvement of mean motion resonances.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"2 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RTModel : Platform for real-time modeling and massive analyses of microlensing events","authors":"V. Bozza","doi":"10.1051/0004-6361/202450450","DOIUrl":"https://doi.org/10.1051/0004-6361/202450450","url":null,"abstract":"The microlensing of stars in our Galaxy has long been used to detect and characterize stellar populations, exoplanets, brown dwarfs, stellar remnants, and all other objects that may magnify the source stars with their gravitational fields. The interpretation of microlensing light curves is relatively simple for single lenses and single sources, but it becomes more and more complicated when we add more objects and take their relative motions into account. RTModel is a modeling platform that has been very active in the real-time investigations of microlensing events, providing preliminary models that have proven very useful for driving follow-up resources towards the most interesting events. The success of RTModel comes from its ability to carry out a thorough and focused exploration of the parameter space in a relatively short time. This modeling process is based on three key ideas. First, the initial conditions are chosen from a template library including all possible caustic crossing and approaches. The fits are then made using the Levenberg-Marquardt algorithm with the addition of a bumper mechanism to explore multiple minima. Finally, the basic computations of microlensing magnification are performed by the fast and robust VBBinaryLensing package. In this paper, we illustrate all the algorithms of RTModel in detail with the intention to foster new approaches in view of future microlensing pipelines aimed at massive microlensing analyses.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"12 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinetic simulations of electron-positron induced streaming instability in the context of gamma-ray halos around pulsars","authors":"Illya Plotnikov, A. J. Marle, C. Gu'epin, A. Marcowith, Pierrick Martin","doi":"10.1051/0004-6361/202449661","DOIUrl":"https://doi.org/10.1051/0004-6361/202449661","url":null,"abstract":"The possibility of slow diffusion regions as the origin for extended TeV emission halos around some pulsars (such as PSR J0633+1746 and PSR B0656+14) challenges the standard scaling of the electron diffusion coefficient in the interstellar medium. Self-generated turbulence by electron-positron pairs streaming out of the pulsar wind nebula was proposed as a possible mechanism to produce the enhanced turbulence required to explain the morphology and brightness of these TeV halos. We perform fully kinetic 1D3V particle-in-cell simulations of this instability, considering the case where streaming electrons and positrons have the same density. This implies purely resonant instability as the beam does not carry any current. We compare the linear phase of the instability with analytical theory and find very reasonable agreement. The non-linear phase of the instability is also studied, which reveals that the intensity of saturated waves is consistent with a momentum exchange criterion between a decelerating beam and growing magnetic waves. With the adopted parameters, the instability-driven wavemodes cover both the Alfv'enic (fluid) and kinetic scales. The spectrum of the produced waves is non-symmetric, with left-handed circular polarisation waves being strongly damped when entering the ion-cyclotron branch, while right-handed waves are suppressed at smaller wavelength when entering the Whistler branch. The low-wavenumber part of the spectrum remains symmetric when in the Alfv'enic branch. As a result, positrons behave dynamically differently compared to electrons. The final drift velocity of positrons can maintain a larger value than the ambient Alfv'en speed $V_A$ while the drift of electrons can drop below $V_A$. We also observed a second harmonic plasma emission in the wave spectrum. An MHD-PIC approach is warranted to probe hotter beams and investigate the Alfv'en branch physics. We provide a few such test simulations to support this assertion. This work confirms that the self-confinement scenario develops essentially according to analytical expectations, but some of the adopted approximations (like the distribution of non-thermal particles in the beam) need to be revised and other complementary numerical techniques should be used to get closer to more realistic configuration.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"7 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141382790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deriving physical parameters of unresolved star clusters. VIII. Limits of aperture photometry for star cluster studies","authors":"K. Daugevicius, E. Krisciunas, Erikas Cicenas, Rima Stonkute, V. Vansevičius","doi":"10.1051/0004-6361/202449680","DOIUrl":"https://doi.org/10.1051/0004-6361/202449680","url":null,"abstract":"Recently, it has been noticed that the discrepancies in the integrated colour indices (CIs) between star clusters and models are mostly due to the projection of bright stars in the apertures. In order to reduce this problem, the method of adaptive aperture photometry has been proposed. This method has been applied to star clusters from the M,31 Panchromatic $Hubble$ Andromeda Treasury (PHAT) survey, and studies show that the adaptive aperture photometry performs better than the conventional approach. The aim of this study is to determine the best achievable limits on the accuracy and applicability of the aperture photometry method for studying star clusters in the local Universe. We computed a large network of artificial 3D star clusters spanning the parameter space of the M,31 clusters. We then simulated images of these clusters by projecting each onto a 2D plane from 100 directions. Star cluster images were generated in six passbands to match the PHAT survey. To investigate the limiting accuracy of aperture photometry and the limits of its applicability to star cluster studies, we measured the simulated images and performed parameter determination tests. We demonstrate that star clusters with and without post-main-sequence stars have significant photometric differences. We show that in order to obtain reliable physical parameters of star clusters, the CIs must be measured using an aperture with a radius larger than the cluster’s half-light radius. Furthermore, we demonstrate that the parameter determination of young clusters (sim 10,Myr) is problematic regardless of the aperture size used. Therefore, it is advisable to determine the parameters of these clusters using colour-magnitude diagram fitting methods, when possible. We also show that the randomness of the viewing angle can lead to a CI uncertainty of up to 0.1,mag, depending on cluster parameters and aperture size.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"12 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AGNfitter-rx : Modeling the radio-to-X-ray spectral energy distributions of AGNs","authors":"L. N. Martínez-Ramírez, G. Calistro Rivera, E. Lusso, F. Bauer, E. Nardini, J. Buchner, J.I. Michael Brown, C.B. Juan Pineda, J. Matthew Temple, Manda Banerji, M. Stalevski, F. Joseph Hennawi","doi":"10.1051/0004-6361/202449329","DOIUrl":"https://doi.org/10.1051/0004-6361/202449329","url":null,"abstract":"We present new advancements in the modeling of the spectral energy distributions (SEDs) of active galaxies by introducing the radio-to-X-ray fitting capabilities of the publicly available Bayesian code AGNfitter . The new code release, called AGNfitter-rx models the broad-band photometry covering the radio, infrared (IR), optical, ultraviolet (UV), and X-ray bands consistently using a combination of theoretical and semi-empirical models of the active galactic nucleus (AGN) and host-galaxy emission. This framework enables the detailed characterization of four physical components of the active nuclei, namely the accretion disk, the hot dusty torus, the relativistic jets and core radio emission, and the hot corona, and can be used to model three components within the host galaxy: stellar populations, cold dust, and the radio emission from the star-forming regions. Applying AGNfitter-rx to a diverse sample of 36 AGN SEDs at $z 0.7$ from the AGN SED ATLAS, we investigated and compared the performance of state-of-the-art torus and accretion disk emission models in terms of fit quality and inferred physical parameters. We find that clumpy torus models that include polar winds and semi-empirical accretion disk templates including emission-line features significantly increase the fit quality in 67 of the sources by reducing by $2 fit residuals in the $1.5-5 1mm m$ and $0.7 1mm m$ regimes. We demonstrate that, by applying AGNfitter-rx to photometric data, we are able to estimate the inclination and opening angles of the torus, consistent with spectroscopic classifications within the AGN unified model, as well as black hole masses congruent with virial estimates based on Halpha . We investigate wavelength-dependent AGN fractions across the spectrum for Type 1 and Type 2 AGNs, finding dominant AGN fractions in radio, mid-infrared, and X-ray bands, which are in agreement with the findings from empirical methods for AGN selection. The wavelength coverage and the flexibility for the inclusion of state-of-the-art theoretical models make AGNfitter-rx a unique tool for the further development of SED modeling for AGNs in present and future radio-to-X-ray galaxy surveys.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of the Bond et al. (2010) SDSS-derived kinematic models for the Milky Way's disk and halo stars with Gaia Data Release 3 proper motion and radial velocity data","authors":"Bruno Dom'inguez, Siddharth Chaini, Karlo Mrakovvci'c, Brandon Sallee, vZeljko Ivezi'c","doi":"10.1051/0004-6361/202449653","DOIUrl":"https://doi.org/10.1051/0004-6361/202449653","url":null,"abstract":"We validate the 2010ApJ...716....1B kinematic models for the Milky Way's disk and halo stars with Gaia Data Release 3 data.\u0000Bond et al. constructed models for stellar velocity distributions using stellar radial velocities measured by the Sloan Digital Sky Survey (SDSS) and stellar proper motions derived from SDSS and the Palomar Observatory Sky Survey astrometric measurements. These models describe velocity distributions as functions of position in the Galaxy, with separate models for\u0000disk and halo stars that were labeled using SDSS photometric and spectroscopic metallicity measurements.\u0000We find that the Bond et al. model predictions are in good agreement with recent measurements of stellar radial velocities\u0000and proper motions by the Gaia survey. In particular, the model accurately predicts the skewed non-Gaussian distribution of rotational velocity for disk\u0000stars and its vertical gradient, as well as the dispersions for all three velocity components.\u0000Additionally, the spatial invariance of velocity ellipsoid for halo stars when expressed in spherical coordinates is also confirmed by Gaia data at galacto-centric radial distances of up to 15 kpc.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"1 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141385956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Very-long-baseline interferometry study of the flaring blazar TXS 1508+572 in the early Universe","authors":"P. Benke, A. Gokus, M. Lisakov, L. Gurvits, F. Eppel, J. Hessdorfer, M. Kadler, Y. Kovalev, E. Ros, F. Rosch","doi":"10.1051/0004-6361/202450153","DOIUrl":"https://doi.org/10.1051/0004-6361/202450153","url":null,"abstract":"High-redshift blazars provide valuable input to studies of the evolution of active galactic nuclei (AGN) jets and provide constraints on cosmological models. Detections at high energies ($0.1< E <100$ GeV) of these distant sources are rare, but when they exhibit bright gamma-ray flares, we are able to study them. However, contemporaneous multi-wavelength observations of high-redshift objects ($z>4$) during their different periods of activity have not been carried out so far. An excellent opportunity for such a study arose when the blazar TXS,1508+572 ($z=4.31$) exhibited a gamma -ray flare in 2022 February in the $0.1-300$ GeV range with a flux 25 times brighter than the one reported in the in the fourth catalog of the Fermi Large Area Telescope. Our goal is to monitor the morphological changes, spectral index and opacity variations that could be associated with the preceding gamma -ray flare in TXS,1508+572 to find the origin of the high-energy emission in this source. We also plan to compare the source characteristics in the radio band to the blazars in the local Universe ($z<0.1$). In addition, we aim to collect quasi-simultaneous data to our multi-wavelength observations of the object, making TXS,1508+572 the first blazar in the early Universe ($z>4$) with contemporaneous multi-frequency data available in its high state. In order to study the parsec-scale structure of the source, we performed three epochs of very-long-baseline interferometry (VLBI) follow-up observations with the Very Long Baseline Array (VLBA) supplemented with the Effelsberg $100$-m Telescope at $15$, $22$, and $43$,GHz, which corresponds to $80$, $117$, and $228$,GHz in the rest frame of TXS,1508+572 . In addition, one $86$,GHz ($456$,GHz) measurement was performed by the VLBA and the Green Bank Telescope during the first epoch. We present total intensity images from our multi-wavelength VLBI monitoring that reveal significant morphological changes in the parsec-scale structure of TXS,1508+572 . The jet proper motion values range from $0.12$ mas/yr to $0.27$ mas/yr, which corresponds to apparent superluminal motion $ app -- $32.2,c$. This is consistent with the high Lorentz factors inferred from the spectral energy distribution (SED) modeling for this source. The core shift measurement reveals no significant impact by the high-energy flare on the distance of the $43$-GHz radio core with respect to the central engine, that means this region is probably not affected by e.g., injection of new plasma as seen in other well-studied sources like CTA,102. We determine the average distance from the $43$-GHz radio core to the central supermassive black hole to be $46.1 that corresponds to a projected distance of $0.32 pc. We estimate the equipartition magnetic field strength $1$ pc from the central engine to be on the order of $0.8$ G, and the non-equipartition magnetic field strength at the same distance to be about $1.7$ G, which values agree well with the magnetic field strength ","PeriodicalId":505693,"journal":{"name":"Astronomy &amp; Astrophysics","volume":"45 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141384407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photometric segregation of dwarf and giant FGK stars using the SVO Filter Profile Service and photometric tools","authors":"Carlos Rodrigo, Patricia Cruz, J. F. Aguilar, Alba Aller, Enrique Solano, M. C. Gálvez-Ortiz, F. Jiménez-Esteban, P. Mas-Buitrago, Amelia Bayo, M. Cortés-Contreras, R. Murillo-Ojeda","doi":"10.1051/0004-6361/202449998","DOIUrl":"https://doi.org/10.1051/0004-6361/202449998","url":null,"abstract":"This paper is focused on the segregation of FGK dwarf and giant stars through narrow-band photometric data using the Spanish Virtual Observatory (SVO) Filter Profile Service and associated photometric tools. We selected spectra from the MILES, STELIB, and ELODIE stellar libraries, and used SVO photometric tools to derive the synthetic photometry in 15 J-PAS narrow filters, which were especially selected to cover spectral features sensitive to gravity changes. Using machine-learning techniques as the Gaussian mixture model and the support vector machine, we defined several criteria based on J-PAS colours to discriminate between dwarf and giant stars. We selected five colour-colour diagrams that presented the most promising separation between both samples. Our results show an overall accuracy in the studied sample of sim 0.97 for FGK stars, although a dependence on the luminosity type and the stellar effective temperature was found. \u0000 We also defined a colour-temperature relation for dwarf stars with effective temperatures between 4,000 and 7,000,K, which allows one to estimate the stellar effective temperature from four J-PAS filters ($J0450$, $J0510$, $J0550$, and $J0620$). Additionally, we extended the study to M-type giant and dwarf stars, achieving a similar accuracy to that for FGK stars.","PeriodicalId":505693,"journal":{"name":"Astronomy &amp; Astrophysics","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141385376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}