Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars

TL;DR

This study evaluates eight reddening and extinction sources for Gaia DR1 main sequence stars, emphasizing the importance of 3D dust modeling for accurate stellar parameter estimation.

Contribution

It compares various reddening estimates and identifies the most reliable 3D methods for nearby stars within 280 pc, improving stellar characterization accuracy.

Findings

3D dust models are essential for accurate reddening correction.

Only certain reddening sources align with stellar population models.

Most stars are embedded in the Galactic dust layer, affecting reddening estimates.

Abstract

We compare eight sources of reddening and extinction estimates for approximately 60,000 {\it Gaia} DR1 Tycho--Gaia Astrometric Solution (TGAS) main sequence stars younger than 3~Gyr with a relative error of the {\it Gaia} parallax less than 0.1. For the majority of the stars, the best 2D dust emission-based reddening maps show considerable differences between the reddening to infinity and the one calculated to the stellar distance using the barometric law of the dust distribution. This proves that the majority of the TGAS stars are embedded in to the Galactic dust layer and a proper 3D treatment of the reddening/extinction is required to reliably calculate their de-reddened colors and absolute magnitudes. The sources with the 3D estimates of reddening are tested in their ability to put the stars among the PARSEC and MIST theoretical isochrones in the Hertzsprung--Russell diagram based on the precise {\it Gaia}, {\it Tycho-2}, 2MASS and {\it WISE} photometry. Only the reddening/extinction estimates by Arenou et al. (1992), Gontcharov (2012), and Gontcharov (2017), being appropriate for nearby stars within 280~pc, provide both the minimal number of outliers bluer than any reasonable isochrone and the correct number of stars younger than 3~Gyr in agreement with the Besan\c{c}on Galaxy model.