The Keck-HGCA Pilot Survey – II. Direct imaging discovery of HD 63754 B, a ∼20 au massive companion near the hydrogen burning limit
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Le résumé fourni par la source
ABSTRACT We present the joint astrometric and direct imaging discovery, mass measurement, and orbital analysis of HD 63754 B (HIP 38216 B), a companion near the stellar-substellar boundary orbiting $\sim$20 au from its Sun-like host. HD 63754 was observed in our ongoing high-contrast imaging survey targeting stars with significant proper-motion accelerations between Hipparcos and Gaia consistent with wide-separation substellar companions. We utilized archival High Resolution Echelle Spectrograph and High Accuracy Radial Velocity Planet Searcher radial velocity (RV) data, together with the host star’s astrometric acceleration extracted from the Hipparcos–Gaia Catalog of Accelerations, to predict the location of the candidate companion around HD 63754 A. We subsequently imaged HD 63754 B at its predicted location using the Near Infrared Camera 2 (NIRC2) in the $L^{\prime }$ band at the W. M. Keck Observatory. We then jointly modelled the orbit of HD 63754 B with RVs, Hipparcos–Gaia accelerations, and our new relative astrometry, measuring a dynamical mass of ${81.9}_{-5.8}^{+6.4} {M_{\rm Jup}}$, an eccentricity of ${0.260}_{-0.059}^{+0.065}$, and a nearly face-on inclination of $174.\!\!^\circ 81_{-0.50}^{+0.48}$. For HD 63754 B, we obtain an $L^{\prime }$-band absolute magnitude of $L^{\prime } = 11.39\pm 0.06$ mag, from which we infer a bolometric luminosity of $\rm{log(L_{\rm bol}/{\rm{L}_{\odot}})= -4.55 \pm 0.08}$ dex using a comparison sample of L and T dwarfs with measured luminosities. Although uncertainties linger in age and dynamical mass estimates, our analysis points towards HD 63754 B’s identity as a brown dwarf on the L/T transition rather than a low-mass star, indicated by its inferred bolometric luminosity and model-estimated effective temperature. Future RV, spectroscopic, and astrometric data such as those from JWST and Gaia Data Release 4 will clarify HD 63754 B’s mass, and enable spectral typing and atmospheric characterization.
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Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- The Keck-HGCA Pilot Survey – II. Direct imaging discovery of HD 63754 B, a ∼20 au massive companion near the hydrogen burning limit
- Date Crossref
- 06/08/2024
- Éditeur
- Oxford University Press (OUP)
- Type
- journal-article
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
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University of California Department of Physics pays non établi dans la noticeUniversité ou école supérieure
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University of Michigan Department of Astronomy pays non établi dans la noticeUniversité ou école supérieure
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The University of Texas at Austin Department of Astronomy pays non établi dans la noticeUniversité ou école supérieure
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The University of Texas at San Antonio Department of Physics and Astronomy pays non établi dans la noticeUniversité ou école supérieure
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University of Edinburgh Institute for Astronomy pays non établi dans la noticeUniversité ou école supérieure
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American Museum of Natural History pays non établi dans la noticeInstitution
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Department of Astrophysics pays non établi dans la noticeInstitution
Department of Physics — University of California, Department of Astronomy — University of Michigan et Department of Astronomy — The University of Texas at Austin, avec 5 autres affiliations.
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