Document Type

Article

Publication Date

7-1-2012

Publication Title

Journal of the Southeastern Association fo Reasearch in Astronomy

Volume

6

Publisher

Southeastern Association for Research in Astronomy

Abstract

We present observations that indicate viscous heating contributes significantly to the surface heating of the inner disk region (0.1-5 AU) around young intermediate-mass stars, Herbig AeBe stars, when the inner disk is optically thick. Brgamma flux is known to scale with accretion rate around young stars. We find a trend between Brgamma and CO emissivity, a tracer 1, 500 K gas in the gaseous atmospheres of less evolved inner disk regions in a sample of 25 Herbig AeBe stars, the higher mass analog of T Tauri stars. Evolved Herbig circumstellar disks do not follow this trend as closely. A thermal chemical model of the inner disk region of T Tauri stars by \citet{gla04} explains the strength and line profiles of observed CO rovibrational emission by showing that accretion contributes significantly to heating the protoplanetary disk. This heating produces the required temperatures and column densities for CO emission in the disk. Our results are consistent with these prescribed disk characteristics. Determining conditions and processes in circumstellar disks around young stars will help inform evolutionary theory and constrain timescales of disk dissipation and planet formation.

Comments

This manuscript has been published in the Journal of the Southeastern Association for Research in Astronomy. Please find the published version here (note that a subscription may be necessary to access this version):

http://jsara.org/JSARA-V06/ms0606-Stevans+Brittain.pdf

Southeastern Association for Research in Astronomy holds the copyright in this article.

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