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摘要
We present a comparison of parallaxes and radii from asteroseismology and Gaia DR1 (TGAS) for 2200 Kepler stars spanning from the main sequence to the red-giant branch. We show that previously identified offsets between TGAS parallaxes and distances derived from asteroseismology and eclipsing binaries have likely been overestimated for parallaxes. 5-10 mas (approximate to 90%-98% of the TGAS sample). The observed differences in our sample can furthermore be partially compensated by adopting a hotter Teff scale (such as the infrared flux method) instead of spectroscopic temperatures for dwarfs and subgiants. Residual systematic differences are at the approximate to 2% level in parallax across three orders of magnitude. We use TGAS parallaxes to empirically demonstrate that asteroseismic radii are accurate to approximate to 5% or better for stars between approximate to 0.8-8 R-circle dot. We find no significant offset for main-sequence (less than or similar to 1.5 R.) and low-luminosity RGB stars (approximate to 3-8 R-circle dot), but seismic radii appear to be systematically underestimated by approximate to 5% for subgiants (approximate to 1.5-3 R-circle dot). We find no systematic errors as a function of metallicity between [Fe/H] approximate to -0.8 to +0.4 dex, and show tentative evidence that corrections to the scaling relation for the large frequency separation (Delta nu) improve the agreement with TGAS for RGB stars. Finally, we demonstrate that beyond approximate to 3 kpc asteroseismology will provide more precise distances than end-of-mission Gaia data, highlighting the synergy and complementary nature of Gaia and asteroseismology for studying galactic stellar populations.
- 出版日期2017-8-1
- 单位中国地震局
