Bayesian distances and extinctions for giants observed by Kepler and APOGEE

Thaíse S Rodrigues,Marc H Pinsonneault,Aldo Serenelli,Szabolcs Mészáros,Cristina Chiappini,Jo Bovy,Gail Zasowski,Dennis Stello,David L Nidever,Rafael A García,Matthew Shetrone,Steven R Majewski,Timothy C Beers,Jennifer A Johnson,Sarbani Basu,Ana E García Pérez,D Bossini ,A Miglio ,S Hekker ,L Girardi ,S Mathur ,W J Chaplin ,M Schultheis ,L A N Da Costa ,B Mosser ,B Santiago ,M A G Maia ,C Allende Prieto ,Courtney R Epstein ,J Montalbán ,Fred Hearty ,Y Elsworth ,F Anders

doi:10.1093/mnras/stu1907

Abstract

We present a first determination of distances and extinctions for individual stars in the first release of the APOKASC catalogue, built from the joint efforts of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and the Kepler Asteroseismic Science Consortium (KASC). Our method takes into account the spectroscopic constraints derived from the APOGEE Stellar Parameters and Chemical Abundances Pipeline, together with the asteroseismic parameters from KASC. These parameters are then employed to estimate intrinsic stellar properties, including absolute magnitudes, using the Bayesian tool PARAM. We then find the distance and extinction that best fit the observed photometry in SDSS, 2MASS, and WISE passbands. The first 1989 giants targeted by APOKASC are found at typical distances between 0.5 and 5 kpc, with individual uncertainties of just ~1.8 per cent. Our extinction estimates are systematically smaller than provided in the Kepler Input Catalogue and by the Schlegel, Finkbeiner and Davis maps. Distances to individual stars in the NGC 6791 and NGC 6819 star clusters agree to within their credible intervals. Comparison with the APOGEE red clump and SAGA catalogues provide another useful check, exhibiting agreement with our measurements to within a few percent. Overall, present methods seem to provide excellent distance and extinction determinations for the bulk of the APOKASC sample. Approximately one third of the stars present broad or multiple-peaked probability density functions and hence increased uncertainties. Uncertainties are expected to be reduced in future releases of the catalogue, when a larger fraction of the stars will have seismically-determined evolutionary status classifications.

Highlights

A number of massive high-resolution spectroscopy surveys (e.g., Apache Point Observatory Galactic Evolution Experiment (APOGEE), Gaia-ESO, ARGOS, GALAH; Majewski et al, in preparation; Gilmore et al 2012; Freeman et al 2013; Freeman 2012) are presently being conducted as part of a major community effort to reveal the evolution and present structure of our Milky Way (MW) galaxy
We present a first determination of distances and extinctions for individual stars in the first release of the APOGEE-KASC collaboration (APOKASC) catalogue, built from the joint efforts of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and the Kepler Asteroseismic Science Consortium (KASC)
Our method takes into account the spectroscopic constraints derived from the APOGEE Stellar Parameters and Chemical Abundances Pipeline, together with the asteroseismic parameters from KASC

Summary

Introduction

A number of massive high-resolution spectroscopy surveys (e.g., APOGEE, Gaia-ESO, ARGOS, GALAH; Majewski et al, in preparation; Gilmore et al 2012; Freeman et al 2013; Freeman 2012) are presently being conducted as part of a major community effort to reveal the evolution and present structure of our Milky Way (MW) galaxy. These surveys promise to greatly expand the available data base of spectroscopic properties such as radial velocities, effective temperatures, surface gravities and chemical abundances. In this paper we concentrate on the latter, discussing the accuracies in dis-

Results

Discussion

Conclusion