| Issue |
A&A
Volume 668, December 2022
|
|
|---|---|---|
| Article Number | A140 | |
| Number of page(s) | 26 | |
| Section | Planets and planetary systems | |
| DOI | https://doi.org/10.1051/0004-6361/202244633 | |
| Published online | 16 December 2022 | |
Precise dynamical masses of new directly imaged companions from combining relative astrometry, radial velocities, and HIPPARCOS-Gaia eDR3 accelerations★,★★
1
European Space Agency (ESA), ESA Office, Space Telescope Science Institute,
3700 San Martin Drive,
Baltimore
21218, MD, USA
e-mail: erickman@stsci.edu
2
Départment d’astronomie de l’Université de Genève,
Chemin Pegasi 51,
1290
Versoix, Switzerland
3
Department of Physics, University of California,
Santa Barbara, CA
93106, USA
4
Univ. Grenoble Alpes, CNRS, IPAG,
38000
Grenoble, France
Received:
29
July
2022
Accepted:
24
September
2022
Aims. With an observing time span of more than 20 yr, the CORALIE radial-velocity survey is able to detect long-term trends in data corresponding to companions with masses and separations accessible to direct imaging. Combining exoplanet detection techniques, such as radial velocities from the CORALIE survey, astrometric accelerations from HIPPARCOS and Gaia eDR3, and relative astrometry from direct imaging, removes the degeneracy of unknown orbital parameters. This allows precise model-independent masses of detected companions to be derived, which provides a powerful tool to test models of stellar and substellar mass-luminosity relations.
Methods. Long-term precise Doppler measurements with the CORALIE spectrograph reveal radial-velocity signatures of companions on long-period orbits. The long baseline of radial-velocity data allows the detectability of the companion candidates to be assessed with direct imaging. We combine long-period radial-velocity data with absolute astrometry from HIPPARCOS and Gaia eDR3 and relative astrometry derived from new direct imaging detections with VLT/SPHERE to fit orbital parameters and derive precise dynamical masses of these companions.
Results. In this paper we report the discovery of new companions orbiting HD 142234, HD 143616, and HIP 22059, as well as the first direct detection of HD 92987 B, and update the dynamical masses of two previously directly imaged companions: HD 157338 B and HD 195010 B. The companions span a period range of 32–279 yr and are all very low-mass stellar companions, ranging from 218 to 487 MJup. We compare the derived dynamical masses to mass-luminosity relations of very low-mass stars (<0.5 M⊙), and discuss the importance of using precursor radial-velocity and astrometric information to inform the future of high-contrast imaging of exoplanets and brown dwarfs.
Key words: binaries: visual / planets and satellites: detection / techniques: radial velocities / techniques: high angular resolution / astrometry
Based on observations collected with SPHERE mounted on the VLT at Paranal Observatory (ESO, Chile) under programs 0102.C-0236(A) (PI: Rickman), 0104.C-0724(A) (PI: Rickman), and 105.20SZ.001 (PI: Rickman) as well as observations collected with the CORALIE spectrograph mounted on the 1.2 m Swiss telescope at La Silla Observatory and with the HARPS spectrograph on the ESO 3.6 m telescope at La Silla (ESO, Chile).
The radial-velocity measurements, reduced images, and additional data products discussed in this paper are available on the DACE web platform at https://dace.unige.ch/ and the links to individual targets are listed in Appendix A.
© E. L. Rickman et al. 2022
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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