【直播】【香港大学物理系colloquium】Interstellar Object

直播信息

报告题目

Interstellar Object: the ‘Oumuamua Conundrum

报告人（单位）

Prof. Douglas N. C. Lin

报告时间

2022年3月9日 10:00

主办方

香港大学物理系

直播二维码

宣传海报

报告人介绍

Prof. Doug Lin’s wide range of research interests include the formation and dynamics ofplanetary systems, star formation and interstellar medium, theory of accretion disks, formationand dynamics of star clusters, interacting galaxies, active galactic nuclei and black holes, andgravitational waves. Prof. Doug Lin received his BSc from McGill University and his PhD fromthe University of Cambridge. He joined the University of California at Santa Cruz in 1979,where he is now Emerita Professor. He was also the Founding Director of the Kavli Institute forAstronomy & Astrophysics at Peking University. He has been awarded the Brouwer Award ofthe Division on Dynamical Astronomy of the American Astronomical Society and the BruceMedal of the Astronomical Society of the Pacific. He is a member of the American Academy ofArts and Science, an Honorary Fellow of the Royal Astronomical Society, and a Legacy Fellow ofthe American Astronomical Society.

报告摘要

In 2017, astronomers detected an elongated object swinging past Earth on its way out of thesolar system. The size and motion of ‘Oumuamua (roughly “scout” in Hawaiian) inspired a fewexcited researchers to suggest the visitation of an interstellar “spaceship.” We revisited thisscenario's three key assumptions: 1) spacecraft removes the large population requirement, 2)solar sail is responsible for the non gravitational acceleration, and 3) a tumbling oblatespheroid accounts for the light curve. We show that such an object would 1) drift way offcourse during its passage through the turbulent, magnetized interstellar medium (similar toair dropping of pamphlets to intended targets on a gusty day), 2) endure comparable amount of radiation-driven acceleration in the anti-solar andsideway direction (contrary to their observed values), and3) have extremely dim phases when the Sun crosses thesurface plane of the thin hypothetical solar sail (analogousto Saturn's ring-plane crossing). Instead, we explore thephysical nature of ‘Oumuamua and a vast fleet of itscohorts and show that they are likely to be the debris oftidally disrupted comets around common low-mass stars.

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编辑：王茹茹

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