X-Ray Irradiation of the LkCa 15 Protoplanetary Disk
Abstract
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, then 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2013
- DOI:
- 10.1088/0004-637X/765/1/3
- arXiv:
- arXiv:1302.2111
- Bibcode:
- 2013ApJ...765....3S
- Keywords:
-
- accretion;
- accretion disks;
- stars: individual: LkCa 15;
- stars: pre-main sequence;
- X-rays: stars;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 3 tables, 3 figures