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, 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.

3 tables, 3 figures

References in corpus (4)

• The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)
• X-ray Emission from T Tauri Stars and the Role of Accretion: Inferences from the XMM-Newton Extended Survey of the Taurus Molecular Cloud
• Cosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks
• Coronal abundances of X-ray bright pre-main sequence stars in the Taurus Molecular Cloud

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• M Stars in the TW Hya Association: Stellar X-rays and Disk Dissipation
• New constraints on the dust and gas distribution in the LkCa 15 disk from ALMA
• Connecting X-ray and Infrared Variability among Young Stellar Objects: Ruling out potential sources of disk fluctuations
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• Molecules in the transition disk orbiting T Cha
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• XMM-Newton X-ray Observations of LkCa 15: A T Tauri Star With a Formative Planetary System
• HCO+ Detection of Dust-Depleted Gas in the Inner Hole of the LkCa 15 Pre-Transitional Disk
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