Spectral analysis of two directly imaged benchmark L dwarf companions at the stellar-substellar boundary
We used multiple epochs of high-contrast imaging spectrophotometric observations to determine the atmospheric characteristics and thermal evolution of two previously detected benchmark L dwarf companions, HD 112863 B and HD 206505 B. We analyzed IRDIS and IFS data from VLT/SPHERE of each companion, both of which have dynamical masses near the stellar-substellar boundary. We compared each companion with empirical spectral standards, and constrained their physical properties through atmospheric model fits. From these analyses, we estimate that HD 112863 B is spectral type L3 ± 1 and that HD 206505 B is spectral type L2 ± 1. Using the BT-Settl atmospheric model grids, we found a bimodal solution for the atmospheric model fit of HD 112863 B where T eff = 1757 −36 +37 K or 2002 −24 +23 K and log g = 4.973 −0.063 +0.057 or 5.253 −0.033 +0.037 , while for HD 206505 B, T eff = 1754 −13 +13 K and log g = 4.919 −0.029 +0.031 . The results of a comparison of the bolometric luminosities of the companions with evolutionary models imply that both companions are likely above the hydrogen burning limit.
Authors
- J. Hagelberg (ORCID: https://orcid.org/0000-0002-1096-1433)
- W. Ceva (ORCID: https://orcid.org/0009-0009-7691-6027)
- D. Ségransan (ORCID: https://orcid.org/0000-0003-2355-8034)
- Emily Rickman (ORCID: https://orcid.org/0000-0003-4203-9715)
- Brendan P. Bowler (ORCID: https://orcid.org/0000-0003-2649-2288)
- T. Forveille (ORCID: https://orcid.org/0000-0003-0536-4607)
- Kyle Franson (ORCID: https://orcid.org/0000-0003-4557-414X)
- Elisabeth C. Matthews (ORCID: https://orcid.org/0000-0003-0593-1560)
- S. Udry (ORCID: https://orcid.org/0000-0001-7576-6236)
- A. Vigan (ORCID: https://orcid.org/0000-0002-5902-7828)
Institutions
- University of Geneva (CH)
- Centre National de la Recherche Scientifique (FR)
- Space Telescope Science Institute (US)
- University of California, Santa Barbara (US)
- Aix-Marseille Université (FR)
- Max Planck Institute for Astronomy (DE)
- The University of Texas at Austin (US)
- Université Grenoble Alpes (FR)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-09-01
- DOI
- https://doi.org/10.1051/0004-6361/202555310
- Citations
- 1
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 1.15
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- European Space Agency
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Université de Genève