Persona: Sarro Baro, Luis Manuel
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0000-0002-5622-5191
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Sarro Baro
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Luis Manuel
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Publicación Gaia Early Data Release 3. The Gaia Catalogue of Nearby Stars(EDP Sciences, 2021-04-28) Smart, R. L.; Sarro Baro, Luis Manuel; Rybizki, Jan; Reylé, Céline; Robin, A. C.; https://orcid.org/0000-0002-4424-4766; https://orcid.org/0000-0002-0993-6089; https://orcid.org/0000-0003-2258-2403Aims. We produce a clean and well-characterised catalogue of objects within 100 pc of the Sun from the Gaia 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. Methods. Theselection 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. Results. We have produced a catalogue of 331 312 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 Gaia Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10 pc of the Sun. Conclusions. We provide the community with a large, well-characterised catalogue of objects in the solar neighbourhood. This is a primary benchmark for measuring and understanding fundamental parameters and descriptive functions in astronomy.Publicación A rich population of free-floating planets in the Upper Scorpius young stellar association(Springer Nature, 2021-12-22) Miret Roig, Nuria; Bouy, Hervé; Raymond, Sean N.; Tamura, Motohide; Bertin, Emmanuel; Barrado, David; Olivares Romero, Javier; Galli, P. A. B.; Cuillandre, Jean-Charles; Sarro Baro, Luis Manuel; Berihuete, Ángel; Huelamo, Nuria; https://orcid.org/0000-0001-5292-0421; https://orcid.org/0000-0002-7084-487X; https://orcid.org/0000-0001-8974-0758; https://orcid.org/0000-0002-6510-0681; https://orcid.org/0000-0002-3602-3664; https://orcid.org/0000-0002-5971-9242; https://orcid.org/0000-0003-2271-9297; https://orcid.org/0000-0002-3263-8645; https://orcid.org/0000-0002-8589-4423; https://orcid.org/0000-0002-2711-8143Free-floating planets (FFPs) are planetary-mass objects that are not bound to host stars. First discovered in the 1990s, their nature and origin are still largely unconstrained because of a lack of large homogeneous samples enabling a statistical analysis of their properties. To date, most FFPs have been discovered using indirect methods; micro-lensing surveys have proven particularly successful to detect these objects down to a few Earth masses1, 2. However, the ephemeral nature of micro-lensing events prevents any follow-up observations and individual characterisation. Several studies have identified FFPs in young stellar clusters3, 4 and the Galactic field5 but their samples are small or heterogeneous in age and origin. Here we report the discovery of between 70 and 170 FFPs (depending on the assumed age) in the region encompassing Upper Scorpius (USC) and Ophiuchus (Oph), the closest young OB association to the Sun. It is the largest homogeneous sample of nearly coeval FFPs discovered to date. We found an excess of FFPs by a factor of up to seven compared to core-collapse models predictions6–8, demonstrating that other formation mechanisms may be at work. We estimate that ejection from planetary systems might have a contribution comparable to that of core-collapse in the formation of FFPs. Therefore, ejections due to dynamical instabilities in giant exoplanet systems must be frequent within the first 10 Myr of a system’s life.Publicación Stellar dating using chemical clocks and Bayesian inference(EDP Sciences, 2022-04-01) Moya, Andrés; Sarro Baro, Luis Manuel; Delgado Mena, Elisa; Chaplin, William; Adibekyan, Vardan; Blanco Cuaresma, Sergi; https://orcid.org/0000-0003-1665-5389; https://orcid.org/0000-0003-4434-2195; https://orcid.org/0000-0002-5714-8618; https://orcid.org/0000-0002-0601-6199; https://orcid.org/0000-0002-1584-0171Context. Dating stars is a major challenge with a deep impact on many astrophysical fields. One of the most promising techniques for this is using chemical abundances. Recent space- and ground-based facilities have improved the quantity of stars with accurate observations. This has opened the door for using Bayesian inference tools to maximise the information we can extract from them. Aims. Our aim is to present accurate and reliable stellar age estimates of FGK stars using chemical abundances and stellar parameters. Methods. We used one of the most flexible Bayesian inference techniques (hierarchical Bayesian models) to exceed current possibilities in the use of chemical abundances for stellar dating. Our model is a data-driven model. We used a training set that has been presented in the literature with ages estimated with isochrones and accurate stellar abundances and general characteristics. The core of the model is a prescription of certain abundance ratios as linear combinations of stellar properties including age. We gathered four different testing sets to assess the accuracy, precision, and limits of our model. We also trained a model using chemical abundances alone. Results. We found that our age estimates and those coming from asteroseismology, other accurate sources, and also with ten Gaia benchmark stars agree well. The mean absolute difference of our estimates compared with those used as reference is 0.9 Ga, with a mean difference of 0.01 Ga. When using open clusters, we reached a very good agreement for Hyades, NGC 2632, Ruprecht 147, and IC 4651. We also found outliers that are a reflection of chemical peculiarities and/or stars at the limit of the validity ranges of the training set. The model that only uses chemical abundances shows slightly worse mean absolute difference (1.18 Ga) and mean difference (−0.12 Ga).