A Candidate Substellar Companion to HR 7329

Abstract

We present the discovery of a candidate substellar companion froma survey of nearby young stars made with the Near-Infrared Cameraand Multiobject Spectrometer coronagraph on the Hubble Space Telescope.The H~12 mag object was discovered approximately 4" from the youngA0 V star HR 7329. Using follow-up spectroscopy from the Space TelescopeImaging Spectrograph, we derive a spectral type between M7 V andM8 V with an effective temperature of ~2600 K. We estimate that theprobability of a chance alignment with a foreground dwarf star ofthis nature is ~10-8, and therefore we suggest that the object (HR7329B) is physically associated with HR 7329, with a projected separationof 200 AU. Current brown dwarf cooling models indicate a mass ofless than 50 MJup for HR 7329B based on age estimates of