Suchergebnisse

Full list of authors: Worley, C. C.; Jofré, P.; Rendle, B.; Miglio, A.; Magrini, L.; Feuillet, D.; Gavel, A.; Smiljanic, R.; Lind, K.; Korn, A.; Gilmore, G.; Randich, S.; Hourihane, A.; Gonneau, A.; Francois, P.; Lewis, J.; Sacco, G.; Bragaglia, A.; Heiter, U.; Feltzing, S.; Bensby, T.; Irwin, M.; Gonzalez Solares, E.; Murphy, D.; Bayo, A.; Sbordone, L.; Zwitter, T.; Lanzafame, A. C.; Walton, N.; Zaggia, S.; Alfaro, E. J.; Morbidelli, L.; Sousa, S.; Monaco, L.; Carraro, G.; Lardo, C. ; Context. The extensive stellar spectroscopic datasets that are available for studies in Galactic Archeaology thanks to, for example, the Gaia-ESO Survey, now benefit from having a significant number of targets that overlap with asteroseismology projects such as Kepler, K2, and CoRoT. Combining the measurements from spectroscopy and asteroseismology allows us to attain greater accuracy with regard to the stellar parameters needed to characterise the stellar populations of the Milky Way. Aims. The aim of this Gaia-ESO Survey special project is to produce a catalogue of self-consistent stellar parameters by combining measurements from high-resolution spectroscopy and precision asteroseismology. Methods. We carried out an iterative analysis of 90 K2@Gaia-ESO red giants. The spectroscopic values of Teff were used as input in the seismic analysis to obtain log g values. The seismic estimates of log were then used to re-determine the spectroscopic values of Teff and [Fe/H]. Only one iteration was required to obtain parameters that are in good agreement for both methods and, thus, to obtain the final stellar parameters. A detailed analysis of outliers was carried out to ensure a robust determination of the parameters. The results were then combined with Gaia DR2 data to compare the seismic log with a parallax-based log and to investigate instances of variations in the velocity and possible binaries within the dataset. Results. This analysis produced a high-quality catalogue of stellar parameters for 90 red giant stars from K2@Gaia-ESO that were determined through iterations between spectroscopy and asteroseismology. We compared the seismic gravities with those based on Gaia parallaxes to find an offset which is similar to other studies that have used asteroseismology. Our catalogue also includes spectroscopic chemical abundances and radial velocities, as well as indicators for possible binary detections. © ESO 2020. ; The authors thank the International Space Science Institute in Bern (ISSI) and Beijing (ISSI-BJ) for supporting and hosting the meetings of the International Team on "AsteroStep" and "Libraries of 2020", respectively, during which the discussions leading and contributing to this publication were initiated and held. PJ acknowledges support of FONDECYT Iniciacion Grant Number 11170174. RS acknowledges support from the National Science Centre (2014/15/B/ST9/03981). A.G., A.K. and U.H. acknowledge support from the Swedish National Space Agency (SNSA/Rymdstyrelsen). T.B. was funded by the project grant "The New Milky Way" from the Knut and Alice Wallenberg Foundation. This work is based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. These data products have been processed by the Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia-ESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council. This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell' Istruzione, dell' Universita' e della Ricerca (MIUR) in the form of the grant "Premiale VLT 2012". The results presented here benefit from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. The authors thank the anonymous referee for the useful comments that improved the manuscript.