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arXiv 2206.04136astro-ph.EPastro-ph.SR
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关于原行星盘的$M_{\rm d} - M_\star$和$\dot M - M_\star$关联的时间演化:粘性时标随恒星质量增加而增加

On the time evolution of the $M_{\rm d} - M_\star$ and $\dot M - M_\star$ correlations for protoplanetary discs: the viscous timescale increases with stellar mass

Alice Somigliana, Claudia Toci, Giovanni Rosotti, Giuseppe Lodato, Marco Tazzari, Carlo Manara, Leonardo Testi, Federico Lepri

摘要:

对恒星形成区的大规模调查揭示了恒星质量和盘参数之间的幂律关系,如盘质量$M_{\mathrm{d}} \propto {M_{\star}}^{λ_{\mathrm{m}}}$和吸积率$\dot M \propto {M_{\star}}^{λ_{\mathrm{acc}}}$。观测到的斜率似乎随着时间的推移而增加,但这些相关性的建立及其随后的演变背后的原因仍然不确定。我们进行了一个理论分析的影响,粘性演化的幂律初始条件人口的原行星盘。我们发现,对于进化种群,粘性进化强制两个相关性具有相同的斜率,$λ_{\mathrm{m}}$ = $λ_{\mathrm{acc}}$,并且这个限制是唯一确定的初始斜率$λ_{\mathrm{m}, 0}$和$λ_{\mathrm{acc}, 0}$。我们恢复的增加趋势时,在初始值的差异,$δ_0 = λ_{\mathrm{m}, 0} - λ_{\mathrm{acc}, 0}$,大于$1/2$的观测声称,此外,我们发现,这种增加的趋势是一个结果的粘性时标和恒星质量之间的正相关性。我们还提出了光盘人口合成数值模拟的结果,使我们能够引入一个蔓延和分析采样的效果,这与我们的分析预测显示出良好的一致性。最后,我们进行了初步的比较,我们的数值结果与观测数据,这使我们能够约束参数空间的初始条件$λ_{\mathrm{m}, 0} \in [1.2, 2.1]$,$λ_{\mathrm{acc}, 0} \in [0.7, 1.5]$。

英文摘要:

Large surveys of star-forming regions have unveiled power-law correlations between the stellar mass and the disc parameters, such as the disc mass $M_{\mathrm{d}} \propto {M_{\star}}^{λ_{\mathrm{m}}}$ and the accretion rate $\dot M \propto {M_{\star}}^{λ_{\mathrm{acc}}}$. The observed slopes appear to be increasing with time, but the reason behind the establishment of these correlations and their subsequent evolution is still uncertain. We conduct a theoretical analysis of the impact of viscous evolution on power-law initial conditions for a population of protoplanetary discs. We find that, for evolved populations, viscous evolution enforces the two correlations to have the same slope, $λ_{\mathrm{m}}$ = $λ_{\mathrm{acc}}$, and that this limit is uniquely determined by the initial slopes $λ_{\mathrm{m}, 0}$ and $λ_{\mathrm{acc}, 0}$. We recover the increasing trend claimed from the observations when the difference in the initial values, $δ_0 = λ_{\mathrm{m}, 0} - λ_{\mathrm{acc}, 0}$, is larger than $1/2$; moreover, we find that this increasing trend is a consequence of a positive correlation between the viscous timescale and the stellar mass. We also present the results of disc population synthesis numerical simulations, that allow us to introduce a spread and analyse the effect of sampling, which show a good agreement with our analytical predictions. Finally, we perform a preliminary comparison of our numerical results with observational data, which allows us to constrain the parameter space of the initial conditions to $λ_{\mathrm{m}, 0} \in [1.2, 2.1]$, $λ_{\mathrm{acc}, 0} \in [0.7, 1.5]$.

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