Stellar multiplicity affects the correlation between protoplanetary disc masses and accretion rates: binaries explain high accretors in Upper Sco
Stellar multiplicity affects the correlation between protoplanetary disc masses and accretion rates: binaries explain high accretors in Upper Sco
复制标题
恒星多重性影响原行星盘质量和吸积率之间的相关性：双星解释了上斯科的高吸积星
DOI：
10.1093/mnras/stac621
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发表时间：
2022
影响因子：
4.8
通讯作者：
Zagaria F
中科院分区：
文献类型：
--
作者：
Zagaria F
近年来，在附近的年轻恒星形成区发现了新生恒星的质量吸积率与它们的原行星盘质量之间的相关性。尽管这种关联可以解释为由于盘中的粘性扩散过程，但在更演化的区域中，具有低质量盘质量的高吸积源仍然令人费解。在这篇文章中，我们假设，恒星伴星的存在截断了圆盘，可以解释这些离群值。首先，我们在文献中搜索关于狼人、查马龙一号和上Sco恒星多重性的信息，发现在关联中涉及的大约20%的圆盘 是双星或更高阶的多恒星系统。我们以很高的统计意义证明，在任何盘质量下，这些源都具有比单星系统更高的吸积率，双星群的大部分都聚集在周围。然后，我们运行潮汐截断圆盘的气体和尘埃耦合一维演化模型，并与数据进行比较。我们发现，这些模型能够很好地再现狼疮和上层Sco中观察到的大部分盘，尽管每个双星的未知偏心率阻止了逐个对象的比较。在后一个区域，如果颗粒凝聚效率降低，一致性就会提高，就像在紧密双星周围的圆盘中所预期的那样。最后，我们提到热风和子结构在解释几个离散源方面可能很重要。
In recent years, a correlation between mass accretion rates onto new-born stars and their protoplanetary disc masses was detected in nearby young star-forming regions. Although such a correlation can be interpreted as due to viscous-diffusion processes in the disc, highly accreting sources with low disc masses in more evolved regions remain puzzling. In this paper, we hypothesize that the presence of a stellar companion truncating the disc can explain these outliers. First, we searched the literature for information on stellar multiplicity in Lupus, Chamaeleon I, and Upper Sco, finding that roughly 20 per cent of the discs involved in the correlation are in binaries or higher order multiple stellar systems. We prove with high statistical significance that at any disc mass these sources have systematically higher accretion rates than those in single-stars, with the bulk of the binary population being clustered around. We then run coupled gas and dust one-dimensional evolutionary models of tidally truncated discs to be compared with the data. We find that these models are able to reproduce well most of the population of observed discs in Lupus and Upper Sco, even though the unknown eccentricity of each binary prevents an object by object comparison. In the latter region, the agreement improves if the grain coagulation efficiency is reduced, as may be expected in discs around close binaries. Finally, we mention that thermal winds and sub-structures can be important in explaining few outlying sources.