Using red clump stars to correct the Gaia DR1 parallaxes

¹ School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
e-mail: g.r.davies@bham.ac.uk
² Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
³ Osservatorio Astronomico di Padova – INAF, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁴ Dipartimento di Fisica e Astronomia, Università di Padova, Vicolo dell’Osservatorio 2, 35122 Padova, Italy
⁵ Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
⁶ Astronomy Unit, Queen Mary University of London, Mile End Road, London E1 4NS, UK

Received: 15 November 2016
Accepted: 10 January 2017

Abstract

Recent results have suggested that there is tension between the Gaia DR1 TGAS distances and the distances obtained using luminosities determined by eclipsing binaries or asteroseismology on red giant stars. We use the K_s-band luminosities of red clump stars, identified and characterized by asteroseismology, to make independent distance estimates. Our results suggest that Gaia TGAS distances contain a systematic error that decreases with increasing distance. We propose a correction to mitigate this offset as a function of parallax that is valid for the Kepler field and values of parallax that are less than ~1.6 mas. For parallaxes greater than this, we find agreement with previously published values. We note that the TGAS distances to the red clump stars of the open cluster M67 show a high level of disagreement that is difficult to correct for.