Confirmation of the Gaia DR2 Parallax Zero-point Offset Using Asteroseismology and Spectroscopy in the Kepler Field

By Joel C. Zinn, M. Pinsonneault, D. Huber, D. Stello. Astrophysical Journal, 2018

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We present an independent confirmation of the zero-point offset of Gaia Data Release 2 parallaxes using asteroseismic data of evolved stars in the Kepler field. Using well-characterized red giant branch stars from the APOKASC-2 catalog, we identify a Gaia astrometric pseudocolor ( ν eff )- and Gaia G-band magnitude-dependent zero-point offset of ϖ seis − ϖ Gaia = 52.8 ± 2.4 (rand.) ± 8.6 (syst.) − (150.7 ± 22.7)( ν eff − 1.5) − (4.21 ± 0.77)(G − 12.2) μas, in the sense that Gaia parallaxes are too small. The offset is found in high- and low-extinction samples, as well as among both shell H-burning red giant stars and core He-burning red clump stars. We show that errors in the asteroseismic radius and temperature scales may be distinguished from errors in the Gaia parallax scale. We estimate systematic effects on the inferred global Gaia parallax offset, c, due to radius and temperature systematics, as well as choices in bolometric correction and the adopted form for Gaia parallax spatial correlations. Because of possible spatially correlated parallax errors, as discussed by the Gaia team, our Gaia parallax offset model is specific to the Kepler field, but broadly compatible with the magnitude- and color-dependent offset inferred by the Gaia team and several subsequent investigations using independent methods.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/18ae0a4f1b0299da3ca25781217456ea09e6e3f0

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Citations in the corpus

A Gaia DR2 view of the open cluster population in the Milky Way (2018, result): “As reported in Lindegren et al. (2018) and Arenou et al. (2018; and confirmed by Riess et al. 2018; Zinn et al. 2018; Stassun & Torres 2018), the Gaia DR2 parallaxes are affected by a zero-point offset.”
Angular Momentum Transport in Stellar Interiors (2018, methodology): “…oscillation modes (n, l,m), where we additionally note that combined Teff , Gaia DR2, and damped modes lead to radii with ∼ 1% precision for the best cases (Zinn et al. 2018); h the potential of this method is largest for p modes and depends on the nature of the pulsating binary (one or two…”
Evidence for a Systematic Offset of −80 μas in the Gaia DR2 Parallaxes (2018, background): “Alternatively, we note that in the Zinn et al. (2018) sample, the brighter stars with G < 11 (more similar in brightness to our EB sample) appear to exhibit a larger systematic offset of ≈ −80 µas, similar to the global offset that we find.”
Milky Way Cepheid Standards for Measuring Cosmic Distances and Application to Gaia DR2: Implications for the Hubble Constant (2018, methodology): “As an illustration, in Figure 7 we use the constraint of −53±2.6 μas on the parallax zeropoint offset calculated from 3475 red giants with Kepler-based asteroseismic estimates of radii and parallaxes from Zinn et al. (2018).”