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arXiv 2109.10296astro-ph.SRastro-ph.EP
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环境对低质量恒星自旋演化的影响。I.星周盘的外部光蒸发

The influence of the environment on the spin evolution of low-mass stars. I. External photoevaporation of circumstellar disks

Julia Roquette, Sean P. Matt, Andrew J. Winter, Louis Amard, Sophia Stasevic

摘要:

大质量恒星是强远紫外辐射源,可能不利于原行星盘的演化,通过外部光蒸发和缩短盘耗散时间尺度来驱动质量损失。它们的影响也可能减少在主序前早期阶段盘和宿主恒星之间角动量交换的时间尺度。为了提高我们对环境对恒星自转历史的影响的理解,我们发展了一个模型,该模型考虑了本地远紫外辐射对低质量恒星自转演化的影响。我们的模型包括一个假设的磁盘锁定,固定的旋转速率在星盘相互作用阶段,与此阶段的持续时间参数化的函数的本地远紫外辐射和恒星质量(在0.1--1.3 M $_\odot$)。通过这种方式,我们展示了来自大质量恒星的反馈如何显着影响恒星的自旋演化,并解释了在像Upper Sco和NGC 2264这样的年轻区域的周期质量分布中观察到的质量依赖性。高质量恒星的高远紫外环境可以使周围恒星的周期分布向快速旋转方向倾斜,解释了疏散星团h Per中快速旋转恒星过多的原因。旋转和主序前环境之间的联系为解释年轻恒星的旋转分布开辟了新的途径。例如,我们认为恒星自转可以作为一个示踪剂的原始紫外线照射的恒星高达$\sim$ 1 Gyr,这提供了一个潜在的方法来连接成熟的行星系统,他们的出生环境。

英文摘要:

Massive stars are strong sources of far-ultraviolet radiation that can be hostile to the evolution of protoplanetary disks, driving mass loss by external photoevaporation and shortening disk-dissipation timescales. Their effect may also reduce the timescale of angular momentum exchanges between the disk and host star during the early pre-main-sequence phase. To improve our understanding of the environmental influence on the rotational history of stars, we developed a model that considers the influence of the local far-ultraviolet radiation on the spin evolution of low mass stars. Our model includes an assumption of disk-locking, which fixes the rotation rate during the star-disk-interaction phase, with the duration of this phase parametrised as a function of the local far-ultraviolet radiation and stellar mass (in the range 0.1--1.3 M$_\odot$). In this way, we demonstrate how the feedback from massive stars can significantly influence the spin evolution of stars and explain the mass-dependency observed in period-mass distributions of young regions like Upper Sco and NGC 2264. The high far-ultraviolet environments of high-mass stars can skew the period distribution of surrounding stars towards fast-rotation, explaining the excess of fast-rotating stars in the open cluster h Per. The proposed link between rotation and the pre-main-sequence environment opens new avenues for interpreting the rotational distributions of young stars. For example, we suggest that stellar rotation may be used as a tracer for the primordial ultraviolet irradiation for stars up to $\sim$1 Gyr, which offers a potential method to connect mature planetary systems to their birth environment.

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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