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arXiv 0801.2100astro-ph
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金牛座T星的盘演化和$L_{\rm acc}$和$L_\ast$之间的关系

Disc evolution and the relationship between $L_{\rm acc}$ and $L_\ast$ in T Tauri stars

I. Tilling, C. J. Clarke, J. E. Pringle, C. A. Tout

摘要:

研究了主序星前吸积光度$L_{\rm acc}$和恒星光度${L_\ast}$的演化。我们假设,当恒星作为第二类物体出现时,吸积的主要阶段早已过去,吸积盘已经进入渐近阶段。我们使用一个近似的恒星演化方案吸积前主序星的基础上哈特曼,卡森和凯尼恩,1997年。我们表明,所观察到的范围内的值$k = L_{\rm acc}/L_\ast$在0.01和1之间可以复制,如果光盘的质量分数$M_{\rm disc}/M_*$的值在金牛座T阶段的开始在于在0.01 - 0.2的范围内,独立于恒星质量。我们还表明,所观察到的上限的$L_{\rm acc} \sim L_\ast$是一个通用的功能,这样的光盘吸积。我们的结论是,只要数据均匀地填充这个上限和观测检测阈值之间的区域,那么年龄,质量和吸积历史之间的退化严重限制了使用这些数据约束可能的缩放盘属性和恒星质量之间。

英文摘要:

We investigate the evolution of accretion luminosity $L_{\rm acc}$ and stellar luminosity ${L_\ast}$ in pre-mainsequence stars. We make the assumption that when the star appears as a Class II object, the major phase of accretion is long past, and the accretion disc has entered its asymptotic phase. We use an approximate stellar evolution scheme for accreting pre-mainsequence stars based on Hartmann, Cassen & Kenyon, 1997. We show that the observed range of values $k = L_{\rm acc}/L_\ast$ between 0.01 and 1 can be reproduced if the values of the disc mass fraction $M_{\rm disc}/M_*$ at the start of the T Tauri phase lie in the range 0.01 -- 0.2, independent of stellar mass. We also show that the observed upper bound of $L_{\rm acc} \sim L_\ast$ is a generic feature of such disc accretion. We conclude that as long as the data uniformly fills the region between this upper bound and observational detection thresholds, then the degeneracies between age, mass and accretion history severely limit the use of this data for constraining possible scalings between disc properties and stellar mass.

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