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arXiv 2005.14200astro-ph.EPastro-ph.SR
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偏心碎片环的意外狭窄:原行星盘阶段偏心的迹象

The unexpected narrowness of eccentric debris rings: a sign of eccentricity during the protoplanetary disc phase

Grant M. Kennedy

摘要:

这篇论文表明,在北落师门和HD 202628恒星周围看到的偏心碎片环比标准偏心行星扰动情景(有时称为“近心辉光”)中预期的要窄。标准的假设是在半长轴$a$上有一个最初的圆形和狭窄的星子带,在气体盘被来自偏心行星的长期扰动分散后,其偏心率增加到$e_f$,导致宽度为$2ae_f$的带。在这个假设的一个小修改中,如果微行星最初是偏心的,可能会出现较窄的带,这可能是由于在富含气体的原行星盘阶段早期的行星扰动。然而,原始偏心率也可能是由增加圆盘偏心率的不稳定性引起的,而不需要任何行星。这些场景是否会在原行星盘中产生可检测到的偏心环尚不清楚,但他们仍然预测在原行星盘中的气体分散之前,应该存在狭窄的偏心星子环。PDS 70被认为是一个拥有不对称原行星盘的系统,它可能是偏心碎片环系统的前身。

英文摘要:

This paper shows that the eccentric debris rings seen around the stars Fomalhaut and HD 202628 are narrower than expected in the standard eccentric planet perturbation scenario (sometimes referred to as "pericenter glow"). The standard scenario posits an initially circular and narrow belt of planetesimals at semi-major axis $a$, whose eccentricity is increased to $e_f$ after the gas disc has dispersed by secular perturbations from an eccentric planet, resulting in a belt of width $2ae_f$. In a minor modification of this scenario, narrower belts can arise if the planetesimals are initially eccentric, which could result from earlier planet perturbations during the gas-rich protoplanetary disc phase. However, a primordial eccentricity could alternatively be caused by instabilities that increase the disc eccentricity, without the need for any planets. Whether these scenarios produce detectable eccentric rings within protoplanetary discs is unclear, but they nevertheless predict that narrow eccentric planetesimal rings should exist before the gas in protoplanetary discs is dispersed. PDS 70 is noted as a system hosting an asymmetric protoplanetary disc that may be a progenitor of eccentric debris ring systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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