A million binaries from <i>Gaia</i> eDR3: sample selection and validation of <i>Gaia</i> parallax uncertainties

El-Badry, Kareem; Rix, Hans─Walter; Heintz, Tyler M.

doi:10.1093/mnras/stab323

Cited by 268 publications

(227 citation statements)

References 69 publications

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“…We applied the corrections to the EDR3 parallaxes as prescribed by Lindegren et al (2021a) 1 , and corrected the PM of bright sources for the spin of the Gaia frame with respect to the ICRS determined by Cantat-Gaudin & Brandt (2021). We also inflated the parallax error bars according to El-Badry et al (2021).…”

Section: Input Data Basic Corrections and Pma Computationmentioning

confidence: 99%

Stellar and substellar companions from Gaia EDR3

Kervella

Arenou

Thévenin

2021

A&A

125

150

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Context. The multiplicity fraction of stars, down to the substellar regime, is a parameter of fundamental importance for stellar formation, evolution, and planetology. The census of multiple stars in the solar neighborhood is however incomplete. Aims. Our study is aimed at detecting companions of Hipparcos catalog stars from the proper motion anomaly (PMa) they induce on their host star, namely, the difference between their long-term Hipparcos-Gaia and short-term Gaia proper motion vectors. We also aim to detect resolved, gravitationally bound companions of the Hipparcos catalog stars (117, 955 stars) and of the Gaia EDR3 stars closer than 100 pc (542,232 stars). Methods. Using the Hipparcos and EDR3 data, we revised the PMa catalog for the Hipparcos stars. In order to identify gravitationally bound visual companions of our sample, we searched the Gaia EDR3 catalog for common proper-motion (CPM) candidates.Results. The detection of tangential velocity anomalies with a median accuracy of σ(∆v T ) = 26 cm s −1 per parsec of distance is demonstrated with the EDR3. This improvement by a factor 2.5 in accuracy, as compared to Gaia DR2, results in PMa detection limits on companions that are well into the planetary mass regime for many targets. We identify 37,515 Hipparcos stars presenting a PMa at significant level (S/N>3), namely, a fraction of 32% (compared to 30% for the DR2) and 12,914 (11%) hosting CPM bound candidate companions. After including the Gaia EDR3 renormalised unit weight error (RUWE>1.4) as an additional indicator, 50,720 stars of the Hipparcos catalog (43%) exhibit at least one signal of binarity. Among the Gaia EDR3 stars located within 100 pc, we find CPM bound candidate companions for 39,490 stars (7.3% of the sample). Conclusions. The search for companions using a combination of the PMa, CPM, and RUWE indicators significantly improves the exhaustivity of the multiplicity survey. The detection of CPM companions of very bright stars (heavily saturated on the Gaia detectors) that are classical benchmark objects for stellar physics provides a useful proxy for estimating their distance with a higher accuracy than with Hipparcos.

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Section: Input Data Basic Corrections and Pma Computationmentioning

confidence: 99%

Stellar and substellar companions from Gaia EDR3

Kervella

Arenou

Thévenin

2021

A&A

125

150

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“…Here, the parallax measurement, = 0.68 ± 0.04 mas, was corrected for its zero point offset following Lindegren et al (2021), and the corresponding uncertainty was inflated using the function of El-Badry et al (2021). The SED fit and stellar parameters are summarised in Table C.1.…”

Section: Appendix A: Observationsmentioning

confidence: 99%

Discovery of a highly magnetic He-sdO star from a double-degenerate binary merger

Dorsch

Reindl

Pelisoli

et al. 2022

A&A

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Helium-rich hot subdwarf stars of spectral type O (He-sdO) are considered prime candidates for stellar merger remnants. Such events should lead to the generation of strong magnetic fields. However, no magnetic He-sdO has yet been unambiguously discovered despite the high magnetic rate (20%) among white dwarf stars, the progeny of hot subdwarfs. Here we present the discovery of a strong magnetic field (B = 353 ± 10 kG) from Zeeman-split hydrogen, helium, and metal lines in the optical X-shooter spectrum of an He-sdO and present the first spectroscopic analysis of any magnetic hot subdwarf. For this we used line-blanketed TLUSTY non-local thermodynamic equilibrium models and assumed a simple homogeneous magnetic field. The derived atmospheric parameters Teff = 44 900 ± 1000 K and log g = 5.93 ± 0.15 are typical for He-sdO stars, while the star is less hydrogen-poor than most He-sdOs at log n(He)/n(H) = + 0.28 ± 0.10. The star is a slow rotator (vrot sin i < 40 km s−1). Its chemical composition is N-rich and C- and O-poor, and the Si and S abundances are close to solar. Combining the atmospheric parameters with Gaia parallax and photometry, the stellar radius and luminosity are found to be typical for He-sdOs and place the star on the helium main sequence in the Hertzsprung-Russell diagram. Its mass of 0.93−0.30+0.44 M⊙, although uncertain, appears to be remarkably high. The strong magnetic field along with the atmospheric parameters and metal abundances provide overwhelming evidence for the double-degenerate merger scenario.

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“…The median effective temperature of our sample equals 4450 K and all our targets have an effective temperature lower than 5800 K. For stars observed by Varga et al (2018), we used the intrinsic luminosities provided by their Spectral Energy Distribution (SED) fits and their extinction estimates, else we used the values provided in the literature (Table 1). We rescaled all luminosities to the Gaia EDR3 distance and considered errors on the parallaxes equal to 1.3 times the errors given in the catalog, as recommended in El-Badry et al (2021) for sources brighter than Gmag = 13, which is the case of our targets. The median luminosity of our T Tauri sample is 2.5 L , with 14 among 17 stars with a luminosity smaller than 10 L .…”

Section: Samplementioning

confidence: 99%

The GRAVITY young stellar object survey

Perraut

Labadie

Bouvier

et al. 2021

A&A

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Context. T Tauri stars are surrounded by dust and gas disks. As material reservoirs from which matter is accreted onto the central star and planets are built, these protoplanetary disks play a central role in star and planet formation. Aims. We aim at spatially resolving at sub-astronomical unit (sub-au) scales the innermost regions of the protoplanetary disks around a sample of T Tauri stars to better understand their morphology and composition. Methods. Thanks to the sensitivity and the better spatial frequency coverage of the GRAVITY instrument of the Very Large Telescope Interferometer, we extended our homogeneous data set of 27 Herbig stars and collected near-infrared K-band interferometric observations of 17 T Tauri stars, spanning effective temperatures and luminosities in the ranges of ~4000–6000 K and ~0.4–10 L⊙, respectively. We focus on the continuum emission and develop semi-physical geometrical models to fit the interferometric data and search for trends between the properties of the disk and the central star. Results. As for those of their more massive counterparts, the Herbig Ae/Be stars, the best-fit models of the inner rim of the T Tauri disks correspond to wide rings. The GRAVITY measurements extend the radius-luminosity relation toward the smallest luminosities (0.4–10 L⊙). As observed previously, in this range of luminosities, the R ∝ L1∕2 trend line is no longer valid, and the K-band sizes measured with GRAVITY appear to be larger than the predicted sizes derived from sublimation radius computation. We do not see a clear correlation between the K-band half-flux radius and the mass accretion rate onto the central star. Besides, having magnetic truncation radii in agreement with the K-band GRAVITY sizes would require magnetic fields as strong as a few kG, which should have been detected, suggesting that accretion is not the main process governing the location of the half-flux radius of the inner dusty disk. The GRAVITY measurements agree with models that take into account the scattered light, which could be as important as thermal emission in the K band for these cool stars. The N-to-K band size ratio may be a proxy for disentangling disks with silicate features in emission from disks with weak and/or in absorption silicate features (i.e., disks with depleted inner regions and/or with large gaps). The GRAVITY data also provide inclinations and position angles of the inner disks. When compared to those of the outer disks derived from ALMA images of nine objects of our sample, we detect clear misalignments between both disks for four objects. Conclusions. The combination of improved data quality with a significant and homogeneous sample of young stellar objects allows us to revisit the pioneering works done on the protoplanetary disks by K-band interferometry and to test inner disk physics such as the inner rim morphology and location.

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A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties

Cited by 268 publications

References 69 publications

Stellar and substellar companions from Gaia EDR3

Stellar and substellar companions from Gaia EDR3

Discovery of a highly magnetic He-sdO star from a double-degenerate binary merger

The GRAVITY young stellar object survey

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