instrumentation: spectrographs; methods: data analysis; techniques: imaging spectroscopy; infrared: planetary systems; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar and Stellar Astrophysics
Abstract :
[en] The determination of the fundamental properties (mass, separation, age, gravity, and atmospheric properties) of brown dwarf companions allows us to infer crucial informations on their formation and evolution mechanisms. Spectroscopy of substellar companions is available to date only for a limited number of objects (and mostly at very low resolution, R < 50) because of technical limitations, I.e. contrast and angular resolution. We present medium resolution (R = 350), coronagraphic long-slit spectroscopic observations with SPHERE of two substellar companions, HD 1160 B and HD 19467 B. We found that HD 1160 B has a peculiar spectrum that cannot be fitted by spectra in current spectral libraries. A good fit is possible only considering separately the Y+J and the H spectral band. The spectral type is between M5 and M7. We also estimated a T[SUB]eff[/SUB] of 2800-2900 K and a log g of 3.5-4.0 dex. The low surface gravity seems to favour young age (10-20 Myr) and low mass (∼20 M[SUB]Jup[/SUB] ) for this object. HD 19467 B is instead a fully evolved object with a T[SUB]eff[/SUB] of ∼1000 K and log g of ∼5.0 dex. Its spectral type is T6 ± 1.
D'Orazi, V.; INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy ; School of Physics and Astronomy, Monash University, Clayton Campus, Victoria 3800, Melbourne, Australia
Vigan, A.; Aix Marseille Université, CNRS, LAM, UMR 7326, F-13388, Marseille, France
Kitzmann, D.; Center for Space and Habitability, University of Bern, Gesellschaftsstrasse 6, CH-3012 Bern, Switzerland
Heng, K.; Center for Space and Habitability, University of Bern, Gesellschaftsstrasse 6, CH-3012 Bern, Switzerland ; Department of Physics, Astronomy & Astrophysics Group, University of Warwick, Coventry CV4 7AL, UK
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