Published July 2023 | Version v1
Journal article

BEAST detection of a brown dwarf and a low-mass stellar companion around the young bright B star HIP 81208

Others:
Stockholm University
INAF - Osservatorio Astronomico di Padova (OAPD) ; Istituto Nazionale di Astrofisica (INAF)
Landessternwarte Königstuhl [ZAH] (LSW) ; Universität Heidelberg [Heidelberg] = Heidelberg University
Observatoire de la Côte d'Azur (OCA) ; Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) ; Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ) ; Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France
Laboratoire d'Astrophysique de Marseille (LAM) ; Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
FRAMATOME
Max-Planck-Institut für Astronomie (MPIA) ; Max-Planck-Gesellschaft
Geneva Observatory ; Université de Genève = University of Geneva (UNIGE)
Centre de Recherche Astrophysique de Lyon (CRAL) ; École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Université de la Nouvelle-Calédonie (UNC)

Description

Recent observations by the B-star Exoplanet Abundance Study (BEAST) illustrate the existence of substellar companions around very massive stars. Here, we present the detection of two lower mass companions to a relatively nearby (148.7 −1.3 +1.5 pc), young (17 −4 +3 Myr), bright ( V = 6.632 ± 0.006 mag), 2.58 ± 0.06 M ⊙ B9V star HIP 81208 residing in the Sco-Cen association using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument at the Very Large Telescope (VLT) in Chile. Our analysis of the photometry obtained gives mass estimates of 67 −7 +6 M J for the inner companion and 0.135 −0.013 +0.010 M ⊙ for the outer companion, indicating that the former is most likely a brown dwarf and the latter a low-mass star. The system is compact but unusual, as the orbital planes of the two companions are likely close to orthogonal. The preliminary orbital solutions we derive for the system indicate that the star and the two companions are likely in a Kozai resonance, rendering the system dynamically very interesting for future studies.

Abstract

International audience

Additional details

Created:
October 11, 2023
Modified:
November 29, 2023