Effect of photodesorption on the snow lines at the surface of optically thick circumstellar disks around Herbig Ae/Be stars

Akinori Oka*, Akio K. Inoue, Taishi Nakamoto, Mitsuhiko Honda

*この研究の対応する著者

研究成果: Article査読

12 被引用数 (Scopus)

抄録

We investigate the effect of photodesorption on the snow line position at the surface of a protoplanetary disk around a Herbig Ae/Be star, motivated by the detection of water ice particles at the surface of the disk around HD142527 by Honda et al. For this aim, we obtain the density and temperature structure in the disk with a 1+1D radiative transfer and determine the distribution of water ice particles in the disk by the balance between condensation, sublimation, and photodesorption. We find that photodesorption induced by far-ultraviolet radiation from the central star depresses the ice-condensation front toward the mid-plane and pushes the surface snow line significantly outward when the stellar effective temperature exceeds a certain critical value. This critical effective temperature depends on the stellar luminosity and mass, the water abundance in the disk, and the yield of photodesorption. We present an approximate analytic formula for the critical temperature. We separate Herbig Ae/Be stars into two groups on the HR diagram according to the critical temperature: one is the disks where photodesorption is effective and from which we may not find ice particles at the surface, and the other is the disks where photodesorption is not effective. We estimate the snow line position at the surface of the disk around HD142527 to be 100-300AU, which is consistent with the water ice detection at >140AU in the disk. All the results depend on the dust grain size in a complex way, and this point requires more work in the future.

本文言語English
論文番号138
ジャーナルAstrophysical Journal
747
2
DOI
出版ステータスPublished - 2012 3月 10
外部発表はい

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学

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