X-ray Irradiation of the LkCa 15 Protoplanetary Disk. (arXiv:1302.2111v1 [astro-ph.SR])

X-ray Irradiation of the LkCa 15 Protoplanetary Disk. (arXiv:1302.2111v1 [astro-ph.SR]):
LkCa 15 in the Taurus star-forming region has recently gained attention as
the first accreting T Tauri star likely to host a young protoplanet. High
spatial resolution infrared observations have detected the suspected
protoplanet within a dust-depleted inner gap of the LkCa 15 transition disk at
a distance of 15 AU from the star. If this object's status as a protoplanet is
confirmed, LkCa 15 will serve as a unique laboratory for constraining physical
conditions within a planet-forming disk. Previous models of the LkCa 15 disk
have accounted for disk heating by the stellar photosphere but have ignored the
potential importance of X-ray ionization and heating. We report here the
detection of LkCa 15 as a bright X-ray source with Chandra. The X-ray emission
is characterized by a cool heavily-absorbed plasma component at kT_cool ~0.3
keV and a harder component at kT_hot ~5 keV. We use the observed X-ray
properties to provide initial estimates of the X-ray ionization and heating
rates within the tenuous inner disk. These estimates and the observed X-ray
properties of LkCa 15 can be used as a starting point for developing more
realistic disk models of this benchmark system.