Authors

René Doyon (1), David Lafrenière (1), Etienne Artigau (1), Lison Malo (1) & Christian Marois (2)

Affiliations

(1) Université de Montréal (2) Herzberg Institute of Astrophysics

Abstract

HR8799 is an A-type star hosting three gravitationally bound planetary mass companions discovered through direct imaging by Marois et al. (2008). Since mass is converted directly from luminosity using age-dependent evolutionary models, the age is a crucial parameter for assessing the physical nature of the HR8799 companions. Marois et al. presented several evidence pointing to a relatively young age for the system, between 30 and 165 Myr, while a recent asteroseismology study (Moya et al. 2010) could possibly imply an age as high as one Gyr that, if true, would bring the HR8799 companions well into the brown dwarf regime. In this paper, I will briefly review the various age indicators for HR8799 and present a Bayesian statistical analysis, through comparison of the observational properties of HR8799 with those of (old) field stars and several nearby young associations, to better constrain the age of the HR8799 system. This analysis suggests, with a high degree of confidence, that HR8799 is unlikely to be a field star and more likely to be a member of the 30-Myr old Columba association.