Combining Gaia and GRAVITY: Characterising five new Directly Detected Substellar Companions

Abstract

Precise mass constraints are vital for the characterisation of brown dwarfs and exoplanets. Here we present how the combination of data obtained by Gaia and GRAVITY can help enlarge the sample of substellar companions with measured dynamical masses. We show how the Non-Single-Star (NSS) two-body orbit catalogue contained in Gaia DR3 can be used to inform high-angular-resolution follow-up observations with GRAVITY. Applying the method presented in this work to eight Gaia candidate systems, we detect all eight predicted companions, seven of which were previously unknown and five are of a substellar nature. Among the sample is Gaia DR3 2728129004119806464 B, which - detected at an angular separation of (34.01 $\pm$ 0.15) mas from the host - is the closest substellar companion ever imaged. This translates to a semi-major axis of (0.938 $\pm$ 0.023) AU. WT 766 B, detected at a greater angular separation, was confirmed to be on an orbit exhibiting an even smaller semi-major axis of (0.676 $\pm$ 0.008) AU. The GRAVITY data were then used to break the host-companion mass degeneracy inherent to the Gaia NSS orbit solutions as well as to constrain the orbital solutions of the respective target systems. Knowledge of the companion masses enabled us to further characterise them in terms of their ages, effective temperatures, and radii via the application of evolutionary models. The inferred ages exhibit a distinct bias towards values younger than what is to be expected based on the literature. The results serve as an independent validation of the orbital solutions published in the NSS two-body orbit catalogue and show that the combination of astrometric survey missions and high-angular-resolution direct imaging holds great promise for efficiently increasing the sample of directly imaged companions in the future, especially in the light of Gaia's upcoming DR4 and the advent of GRAVITY+.

Accepted for publication in Astronomy and Astrophysics

References in corpus (46)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• emcee: The MCMC Hammer
• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• Color Transformations for the 2MASS Second Incremental Data Release
• The Gemini Planet Imager: First Light
• First Light for GRAVITY: Phase Referencing Optical Interferometry for the Very Large Telescope Interferometer
• SPHERE: the exoplanet imager for the Very Large Telescope
• On the Luminosity of Young Jupiters
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• The Mauna Kea Observatories Near-Infrared Filter Set. II. Specifications for a New JHKL'M' Filter Set for Infrared Astronomy
• Imaging Extrasolar Giant Planets
• Astrometric exoplanet detection with Gaia
• A new set of atmosphere and evolution models for cool T-Y brown dwarfs and giant exoplanets
• The Hipparcos-Gaia Catalog of Accelerations: Gaia EDR3 Edition
• JHK Standard Stars for Large Telescopes: the UKIRT Fundamental and Extended Lists
• Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure
• Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs
• The SPHERE infrared survey for exoplanets (SHINE). III. The demographics of young giant exoplanets below 300 au with SPHERE
• Large Interferometer For Exoplanets (LIFE): I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
• Gaia Data Release 3: Catalogue Validation
• Constraining the initial entropy of directly-detected exoplanets
• Gaia Data Release 3. Astrometric binary star processing
• Peering into the formation history of beta Pictoris b with VLTI/GRAVITY long baseline interferometry
• MIRACLES: atmospheric characterization of directly imaged planets and substellar companions at 4-5 $\mu$m. I. Photometric analysis of $\beta$ Pic b, HIP 65426 b, PZ Tel B and HD 206893 B
• Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY
• Direct confirmation of the radial-velocity planet $\beta$ Pic c
• Luminosity of young Jupiters revisited. Massive cores make hot planets
• The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data
• AF Lep b: the lowest mass planet detected coupling astrometric and direct imaging data
• Direct discovery of the inner exoplanet in the HD206893 system. Evidence for deuterium burning in a planetary-mass companion
• Direct imaging discovery of a super-Jovian around the young Sun-like star AF Leporis
• Astrometric Accelerations as Dynamical Beacons: A Giant Planet Imaged Inside the Debris Disk of the Young Star AF Lep
• Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3
• The GRAVITY fringe tracker
• Signatures of Cloud, Temperature, and Gravity From Spectra of the Closest Brown Dwarfs
• Transit Probabilities for Stars With Stellar Inclination Constraints
• The First Dynamical Mass Measurement in the HR 8799 System
• A deep X-ray view of the bare AGN Ark120. V. Spin determination from disc-Comptonisation efficiency method
• GRAVITY K-band spectroscopy of HD 206893 B: brown dwarf or exoplanet
• A dusty benchmark brown dwarf near the ice line of HD 72946
• The CORALIE survey for southern extrasolar planets XIX. Brown dwarfs and stellar companions unveiled by radial velocity and astrometry
• Combining Hipparcos and Gaia data for the study of binaries: the BINARYS tool

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• The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) I: Motivation, sample, data reduction, and results overview
• The SPHERE infrared survey for exoplanets (SHINE). V. Complete observations, data reduction and analysis, detection performances, and final results
• The ExoGRAVITY survey: A K-band spectral library of giant exoplanet and brown dwarf companions
• Astrometric exomoon detection by means of optical interferometry
• Machine learning-based identification of Gaia astrometric exoplanet orbits
• The mid-infrared spectrum of $\beta$ Pictoris b. First VLTI/MATISSE interferometric observations of an exoplanet
• Component masses in stellar and substellar binaries from Gaia astrometry and photometry