2018/04/30 by Johanna Coronado, Hans-Walter Rix, Hans‐Walter Rix +2 · 20 citations
Physics and Astronomy · #Astronomical and nuclear sciences #Astronomy #Astronomy and Astrophysical Research #Astrophysics #LAMOST #Milky Way #Parallax #Physics #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1093/mnras/sty2468
published in Monthly Notices of the Royal Astronomical Society 481(3), 2970-2980 (Oxford University Press) · 12 pages, 13 figures. Accepted for publication in MNRAS
openalex created_date 2018/05/07 · openalex publication_date 2018/09/07 · arxiv created 2018/09/10 · arxiv updated 2018/09/11 · openalex updated_date 2026/08/05
Spectrophotometric distances to stars observed by large spectroscopic surveys offer a crucial complement to parallax distances that remain very important also after the future Gaia data releases. Here, we present a probabilistic approach to modelling spectroscopic information for a subset of 4000 main sequence stars with good parallaxes (σϖ/ϖ < 0.1) from the LAMOST × TGAS × 2MASS cross-match, yielding a precise spectroscopic distance estimator with uncertainties of ∼6 per cent for single stars. Unlike previous approaches to this problem, we explicitly account for the individual parallax uncertainties in the model building and fully incorporate the fraction of near-equal binaries of main sequence stars, which would lead to biased distance estimates if neglected. Using this model, we estimate the distance for all (150 000) main sequence stars from LAMOST Data Release 5, without parallax information. As an application, we compute their orbital actions, where our more precise distances result in 5 times smaller action uncertainties. This illustrates how future studies of the Milky Way’s orbital structure can benefit from using our model. For the fainter and more distant stars of most current spectroscopic surveys, an approach such as the one presented in this work will deliver better distances than Gaia Data Release 2.