On the origin of the correlations between the accretion luminosity and emission line luminosities in pre-main-sequence stars
On the origin of the correlations between the accretion luminosity and emission line luminosities in pre-main-sequence stars
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DOI：
10.1093/mnras/stv1540
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发表时间：
2015-07
影响因子：
4.8
通讯作者：
I. Mendigut'ia;R. Oudmaijer;E. Rigliaco;J. Fairlamb;N. Calvet;J. Muzerolle;N. Cunningham;S. Lumsden
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文献类型：
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作者：
I. Mendigut'ia;R. Oudmaijer;E. Rigliaco;J. Fairlamb;N. Calvet;J. Muzerolle;N. Cunningham;S. Lumsden
前主序 (PMS) 恒星的吸积光度和发射线光度（Lacc 和 Lline）之间的相关性已针对许多不同的谱线发表，用于估计吸积率。尽管这些相关性的起源尚不清楚，但这可能归因于发射线形成和吸积机制之间的直接或间接物理关系。这项工作表明，所有（近紫外/光学/近红外）Lacc-L线相关性都是吸积光度和恒星光度（L*）相关的结果，并且不一定与线的物理起源有关。综合和观测数据用于说明 Lacc-Lline 相关性如何依赖于 Lacc-L* 关系。我们的结论是，由于PMS恒星显示出Lacc-L*相关性，因此立即意味着Lacc也与所有发射线的光度相关，因此Lacc-L线相关性本身并不能证明与吸积有任何物理联系，而只能用于粗略估计吸积率的实际目的。当寻找可能具有物理意义的相关性时，我们建议使用 Lacc/L* 和 Lline/L* 而不是 Lacc 和 Lline。最后，还讨论了金牛座 T 星的 Lacc 对 L* 的依赖性比中等质量 Herbig Ae/Be 星更强烈的依赖性。这是从磁层吸积情景和近紫外线中不同的光球特性来解释的。
Correlations between the accretion luminosity and emission line luminosities (Lacc and Lline) of pre-main-sequence (PMS) stars have been published for many different spectral lines, which are used to estimate accretion rates. Despite the origin of those correlations is unknown, this could be attributed to direct or indirect physical relations between the emission line formation and the accretion mechanism. This work shows that all (near-UV/optical/near-IR) Lacc–Lline correlations are the result of the fact that the accretion luminosity and the stellar luminosity (L*) are correlated, and are not necessarily related with the physical origin of the line. Synthetic and observational data are used to illustrate how the Lacc–Lline correlations depend on the Lacc–L* relationship. We conclude that because PMS stars show the Lacc–L* correlation immediately implies that Lacc also correlates with the luminosity of all emission lines, for which the Lacc–Lline correlations alone do not prove any physical connection with accretion but can only be used with practical purposes to roughly estimate accretion rates. When looking for correlations with possible physical meaning, we suggest that Lacc/L* and Lline/L* should be used instead of Lacc and Lline. Finally, the finding that Lacc has a steeper dependence on L* for T Tauri stars than for intermediate-mass Herbig Ae/Be stars is also discussed. That is explained from the magnetospheric accretion scenario and the different photospheric properties in the near-UV.