Infalling Planetesimals in Young Star Clusters

PI：Pilachowski博士皮拉科夫斯基获得了印第安纳州大学的资助，利用最近在年轻星星系统中发现的“下落蒸发体”（FEB）来研究行星形成的时间尺度。 FEB是微行星，其轨道受到新形成的行星的扰动。 这些微行星要么从行星系统中被抛出，要么被送入轨道，撞击或擦过中心的星星。 在星星附近，星子被加热并变成气体，可以通过它们的瞬态光谱吸收特征来检测。 FEB提供了星星系统中行星和微行星的直接证据，也提供了有关系统动力学和微行星组成的信息。 在具有明确质量和年龄的年轻恒星样本中观测FEBs可能会限制行星形成的时间尺度和/或轨道迁移的机制。 Pilachowski博士将研究年龄从几百万年到3000万年的年轻星星团中的晚B和早A矮星，以探索星子可能通过行星的形成和轨道迁移从年轻的太阳系中清除出来的时间尺度。这些恒星将使用3.5米的威斯康星-印第安纳-耶鲁-NOAO（WIYN）望远镜和多目标光谱仪进行光谱监测。 PI将让研究生和本科生参与这项工作，并预计这项对太阳系外行星系统中“彗星”的研究可能会吸引广泛的公众兴趣，并激发儿童的想象力。***

PI: PilachowskiDr. Pilachowski is awarded funds at Indiana University to use the recently discovered "falling evaporative bodies" (FEBs) in young star systems to study the timescale for the formation of planets. FEBs are planetesimals whose orbits are perturbed by newly formed planets. The planetesimals are either ejected from the planetary system or sent inward on orbits that impact or graze the central star. Near the star, the planetesimals are heated and turned to gas, and can be detected by their transient spectral absorption features. The FEBs offer direct evidence of planets and planetesimals in the star system, and also provide information about the dynamics of the system and the composition of the planetesimals. Observations of FEBs in a sample of young stars with well-defined masses and ages may constrain the timescale of planet formation and/or the mechanism of orbital migration. Dr. Pilachowski will examine late B and early A dwarf stars in young star clusters ranging in age from a few million years up to 30 million years to explore the timescales over which planetesimals may be cleared out of young solar systems by the formation of planets and by orbital migration. The stars will be monitored spectroscopically using the 3.5-m Wisconsin-Indiana-Yale-NOAO (WIYN) telescope and multi-object spectrograph. The PI will involve both graduate and undergraduate students in the work, and expects that this study of "comets" in extra-solar planetary systems is likely to attract broad public interest and to fire the imaginations of children. ***