Chandra X-ray detection of the enigmatic field star BP Psc.
KASTNER J.H., MONTEZ R., RODRIGUEZ D., GROSSO N., ZUCKERMAN B., PERRIN M.D., FORVEILLE T. and GRAHAM J.R.
Abstract (from CDS):
BP Psc is a remarkable emission-line field star that is orbited by a dusty disk and drives a parsec-scale system of jets. We report the detection by the Chandra X-ray Observatory of a weak X-ray point source coincident with the centroids of optical/IR and submillimeter continuum emission at BP Psc. As the star's photosphere is obscured throughout the visible and near-infrared, the Chandra X-ray source likely represents the first detection of BP Psc itself. The X-rays most likely originate with magnetic activity at BP Psc and hence can be attributed either to a stellar corona or to star-disk interactions. The log of the ratio of X-ray to bolometric luminosity, log(LX/Lbol), lies in the range -5.8 to -4.2. This is smaller than log(LX/Lbol) ratios typical of low-mass, pre-main sequence stars, but is well within the log(LX/Lbol) range observed for rapidly rotating (FK Com-type) G giant stars. Hence, the Chandra results favor an exotic model wherein the disk/jet system of BP Psc is the result of its very recently engulfing a companion star or a giant planet, as the primary star ascended the giant branch.