Orbiting a binary: SPHERE characterisation of the HD 284149 system
Abstract
In this paper we present the results of the SPHERE observation of the HD 284149 system, aimed at a more detailed characterisation of both the primary and its brown dwarf companion. We observed HD 284149 in the near-infrared with SPHERE, using the imaging mode (IRDIS+IFS) and the long-slit spectroscopy mode (IRDIS-LSS). The data were reduced using the dedicated SPHERE pipeline, and algorithms such as PCA and TLOCI were applied to reduce the speckle pattern. The IFS images revealed a previously unknown low-mass (~0.16) stellar companion (HD 294149 B) at ~0.1, compatible with previously observed radial velocity differences, as well as proper motion differences between Gaia and Tycho-2 measurements. The known brown dwarf companion (HD 284149 b) is clearly visible in the IRDIS images. This allowed us to refine both its photometry and astrometry. The analysis of the medium resolution IRDIS long slit spectra also allowed a refinement of temperature and spectral type estimates. A full reassessment of the age and distance of the system was also performed, leading to more precise values of both mass and semi-major axis. As a result of this study, HD 284149 ABb therefore becomes the latest addition to the (short) list of brown dwarfs on wide circumbinary orbits, providing new evidence to support recent claims that object in such configuration occur with a similar frequency to wide companions to single stars.
Cite
@article{arxiv.1707.06238,
title = {Orbiting a binary: SPHERE characterisation of the HD 284149 system},
author = {Mariangela Bonavita and V. D'Orazi and D. Mesa and C. Fontanive and S. Desidera and S. Messina and S. Daemgen and R. Gratton and A. Vigan and M. Bonnefoy and A. Zurlo and J. Antichi and H. Avenhaus and A. Baruffolo and J. L. Baudino and J. L. Beuzit and A. Boccaletti and P. Bruno and T. Buey and M. Carbillet and E. Cascone and G. Chauvin and R. U. Claudi and V. De Caprio and D. Fantinel and G. Farisato and M. Feldt and R. Galicher and E. Giro and C. Gry and J. Hagelberg and S. Incorvaia and M. Janson and M. Jaquet and A. M. Lagrange and M. Langlois and J. Lannier and H. Le Coroller and L. Lessio and R. Ligi and A. L. Maire and F. Menard and C. Perrot and S. Peretti and C. Petit and J. Ramos and A. Roux and B. Salasnich and G. Salter and M. Samland and S. Scuderi and J. Schlieder and M. Surez and M. Turatto and L. Weber},
journal= {arXiv preprint arXiv:1707.06238},
year = {2017}
}
Comments
15 pages, 16 figures