The close stellar companion to the hot Jupiter system WASP-9
PI:
Pierre Maxted
Co-I(s):
David Anderson, Sam Bentley, Didier Queloz, Pedro Figueira, Michael Gillon, Coel Hellier, Tsevi Mazeh, Barry Smalley, David Wilson, Damien Segransan
Abstract
We have recently discovered that the bright F7V star WASP-9 has a hot Jupiter companion. Uniquely among such systems, it also has a low-mass stellar companion with an orbital period of a few years. The companion has been detected indirectly from the long-term variations in the mean radial velocity of the F7 star, so we only have a lower limit to the companion's
mass. This system poses a major challenge to current theories for the formation of hot Jupiters because the separation of the stars is less than the size of a proto-planetary disc. The orbit is at a phase where we can resolve the companion's spectrum for the next few months, an opportunity that will not be repeated for several years. We will use Phoenix spectroscopy to directly detect the companion and measure its mass.