Gaia Data Release 2

By R. Andrae, Morgan Fouesneau, O. Creevey, C. Ordenovic, N. Mary, A. Burlacu, L. Chaoul, A. Jean-Antoine-Piccolo, G. Kordopatis, A. Korn and 6 more. Astronomy & Astrophysics, 2018

160 citations recorded by the source corpus.

The second Gaia data release (Gaia DR2) contains, beyond the astrometry, three-band photometry for 1.38 billion sources. One band is the G band, the other two were obtained by integrating the Gaia prism spectra (BP and RP). We have used these three broad photometric bands to infer stellar effective temperatures, Teff, for all sources brighter than G = 17 mag with Teff in the range 3000–10 000 K (some 161 million sources). Using in addition the parallaxes, we infer the line-of-sight extinction, AG, and the reddening, E(BP − RP), for 88 million sources. Together with a bolometric correction we derive luminosity and radius for 77 million sources. These quantities as well as their estimated uncertainties are part of Gaia DR2. Here we describe the procedures by which these quantities were obtained, including the underlying assumptions, comparison with literature estimates, and the limitations of our results. Typical accuracies are of order 324 K (Teff), 0.46 mag (AG), 0.23 mag (E(BP − RP)), 15% (luminosity), and 10% (radius). Being based on only a small number of observable quantities and limited training data, our results are necessarily subject to some extreme assumptions that can lead to strong systematics in some cases (not included in the aforementioned accuracy estimates). One aspect is the non-negativity contraint of our estimates, in particular extinction, which we discuss. Yet in several regions of parameter space our results show very good performance, for example for red clump stars and solar analogues. Large uncertainties render the extinctions less useful at the individual star level, but they show good performance for ensemble estimates. We identify regimes in which our parameters should and should not be used and we define a “clean” sample. Despite the limitations, this is the largest catalogue of uniformly-inferred stellar parameters to date. More precise and detailed astrophysical parameters based on the full BP/RP spectrophotometry are planned as part of the third Gaia data release.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/1cb1a4bea63cdb0135a65bde564eb47e54149e65

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In Astronomy and Astrophysics

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Citations in the corpus

• The Revised TESS Input Catalog and Candidate Target List (2019, methodology): “Andrae et al. (2018) also provide additional polynomials to describe the error in BCG as a function of Teff , based essentially on the scatter as a function of log g; we adopt these errors as well.”
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18 (2019, methodology): “Due to the limited number of observables used (parallax + Gaia DR2 photometry), the output parameters Teff and AG are strongly correlated, and therefore suffer from a number of caveats documented in Gaia DR2 (see Andrae et al. 2018 for an extensive discussion).”
• Painting a portrait of the Galactic disc with its stellar clusters (2020, background): “The use of ground-based photometry, especially at nonoptical wavelengths, and value-added catalogues containing astrophysical parameters for individual stars (Andrae et al. 2018; Anders et al. 2019) could help to provide better constraints on the cluster parameters.”
• Occurrence Rates of Planets Orbiting FGK Stars: Combining Kepler DR25, Gaia DR2, and Bayesian Inference (2019, unknown): “Once Gaia provided accurate parallaxes for most Kepler target stars (Gaia Collaboration et al. 2018), accurate stellar radii and uncertainties were derived for those targets (Andrae et al. 2018).”
• A Gaia DR2 view of the open cluster population in the Milky Way (2018, methodology): “…not attempt to correct the photometry of individual sources from interstellar extinction using the Gaia DR2 values of AG and E(BP − RP), as their nominal uncertainties (∼0.46 mag in AG, Andrae et al. 2018) do not allow us to improve the aspect of a cluster sequence in a colour-magnitude diagram.”
• Age determination for 269 Gaia DR2 open clusters (2019, background): “However, BASE-9 runs show that using only these magnitudes is not possible to resolve the degeneracy between the four cluster parameters, mainly the distance modulus and the extinction (see also Andrae et al. 2018).”
• A 3D Dust Map Based on Gaia, Pan-STARRS 1, and 2MASS (2019, methodology): “This is an order of magnitude more stellar reddenings than are provided by the Gaia DR2 catalog (Andrae et al. 2018).”
• On the use of Gaia magnitudes and new tables of bolometric corrections (2018, unknown): “In our grid, there is no ambiguity in the zero-point of the BCs, which is instead an unnecessary source of biases when matching a synthetic grid to heterogeneous observations (Andrae et al. 2018).”
• Angular Momentum Transport in Stellar Interiors (2018, background): “…calibration stars, as well as a high-precision parallax and Teff , limiting the application to bright stars; d typical values covering 77 million stars (Andrae et al. 2018); e isochrone fitting of (Extended) Main-Sequence Turnoffs, (E)MST, of clusters from combined multi-color photometry,…”