Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars

Abstract

We compare eight sources of reddening and extinction estimates for approximately 60,000 Gaia DR1 Tycho-Gaia Astrometric Solution (TGAS) main sequence stars younger than 3 Gyr with a relative error of the 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 Gaia, Tycho-2, 2MASS and 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 Besançon Galaxy model.

MOBSTER – II. Identification of rotationally variable A stars observed with TESS in sectors 1–4

“…Colour excess values (E[B − V ]) associated with 1 885 and 1 457 of the 1 962 stars in our sample are listed in the TIC and reported by Gontcharov & Mosenkov (2017), respectively. We found that de-reddening the flux measurements using the values taken from either of these catalogs prior to carrying out the SED fitting analysis yielded a large number of T eff values that are significantly greater than is expected for A-type stars (T eff > 12 000 K).…”

Interstellar polarization and extinction in the Local Bubble and the Gould Belt

“…However, various definitions of the Bubble by estimating E(B − V) at its boundary are contradictory: E(B − V) < 0.010 (FitzGerald 1968), E(B −V) < 0.045 (Frisch 2007), E(B −V) < 0.053 given E(b − y) < 0.04 and E(B − V) = 1.335 E(b − y) (Lallement et al 2014), and even E(B − V) < 0.055 given the extinction-to-reddening ratio R V ≡ A V /E(B − V) = 3.1 and A V < 0.17 mag . A typical accuracy of all these estimates seems to be σ(E(B − V)) > 0.02 mag (Gontcharov & Mosenkov 2017b). With such a high uncertainty, it is still to be confirmed, whether the Bubble has lower dust volume density, E(B − V)/R and A V /R.…”

“…With the median |Z | = 122 pc, most stars of our sample are located inside the inhomogeneous Galactic dust layer. The authors of the selected reddening data sources have made some efforts to take it into account (Gontcharov & Mosenkov 2017b). However, their median E(B − V) for our sample are very diverse: 0.087, 0.075, 0.048, 0.038, and 0.027 mag for G17, G12, AGG, DCL, and LVV, respectively.…”

“…Reddening estimates from many other data sources are not applicable to stars inside the dust layer within 500 pc from the Sun, as pointed out by Gontcharov & Mosenkov (2017b, 2018). An example is the 2D (to infinity) reddening maps by SFD and Meisner & Finkbeiner (2015), based on the observations of the dust emission in far-IR by COBE, IRAS, and Planck.…”

Isochrone fitting of Galactic globular clusters – I. NGC 5904

“…For example, Meisner & Finkbeiner (2015), Schlafly & Finkbeiner (2011), Drimmel, Cabrera-Lavers & López-Corredoira (2003, and Lallement et al (2018) have similar reddening zero points by use of the same data from SFD or by use of SFD as the prior for a poor dataset at such a high latitude (b ≈ 47 • ). More details on this topic are presented by Gontcharov & Mosenkov (2017b, 2019.…”