Discovery of a brown dwarf companion to the star HIP 64892
Rouan, D.; Henning, T.; Fantinel, D.; Dominik, C.; Ségransan, D.; Turatto, M.; D'Orazi, V.; Udry, S.; Fusco, T.; Costille, A.; Menard, F.; Zurlo, A.; Boccaletti, A.; Janson, M.; Keppler, M.; Kral, Q.; Langlois, M.; Ligi, R.; Maire, A. -L.; Meyer, M.; Sauvage, J. -F.; Baruffolo, A.; Baudoz, P.; Le Mignant, D.; Maurel, D.; Ramos, J.; Weber, L.; Lagrange, A. -M.; Claudi, R.; Desidera, S.; Bonnefoy, M.; Cheetham, A.; Hagelberg, J.; Mesa, D.; Gratton, R.; Olofsson, J.; Vigan, A.; Chauvin, G.; Beuzit, J. -L.; Mouillet, D.; Peretti, S.; Sissa, E.; Abe, L.; Feldt, M.; Madec, F.; Perret, D.; Petit, C.; Rabou, P.; Soenke, C.; Möller-Nilsson, O.; Lagadec, E.; Mordasini, C.; Pavlov, A.; Hubin, N.; Rochat, S.; Stadler, E.; Roux, A.; Martinez, P.; Biller, B.; Le Coroller, H.; Wildi, F.; Buey, T.; Giro, E.; Kasper, M.; Cascone, E.; Schmidt, T.; Roelfsema, R.; Pragt, J.; Carle, M.; Feautrier, P.; Delboulbé, A.; Gluck, L.; Kopytova, T.; Antichi, J.; Blanchard, P.; Carbillet, M.; De Caprio, V.; Dohlen, K.; Hugot, E.; Jaquet, M.; Llored, M.; Magnard, Y.; Moulin, T.; Origné, A.; Puget, P.; Rigal, F.; Rousset, G.; Salasnich, B.; Sevin, A.; Suarez, M.; Klahr, H.; Schlieder, J.
Switzerland, France, Italy, Germany, Chile, Sweden, United Kingdom, United States, Russia, Netherlands
Abstract
We report the discovery of a bright, brown dwarf companion to the star HIP 64892, imaged with VLT/SPHERE during the SHINE exoplanet survey. The host is a B9.5V member of the Lower-Centaurus-Crux subgroup of the Scorpius Centaurus OB association. The measured angular separation of the companion (1.2705 ± 0.0023") corresponds to a projected distance of 159 ± 12 AU. We observed the target with the dual-band imaging and long-slit spectroscopy modes of the IRDIS imager to obtain its spectral energy distribution (SED) and astrometry. In addition, we reprocessed archival NACO L-band data, from which we also recover the companion. Its SED is consistent with a young (<30 Myr), low surface gravity object with a spectral type of M9γ ± 1. From comparison with the BT-Settl atmospheric models we estimate an effective temperature of Teff = 2600 ± 100 K, and comparison of the companion photometry to the COND evolutionary models yields a mass of 29-37 MJ at the estimated age of 16-7+15 Myr for the system. The star HIP 64892 is a rare example of an extreme-mass ratio system (q 0.01) and will be useful for testing models relating to the formation and evolution of such low-mass objects.
Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 096.C-0241 and 198.C-0209 (PI: J.-L. Beuzit), 098.A-9007(A) (PI: P. Sarkis), and 087.C-0790(A) (PI: M. Ireland).