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Physics Colloquium

Thursday, October 26, 2023
4:00pm to 5:00pm
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Online and In-Person Event
Companion-Disk Interaction: From Protoplanetary Disks to AGN Disks
Zhaohuan Zhu, UNLV,

In Astrophysics, we have two types of objects: spherical objects (e.g. planets, stars, compact objects) and disk objects (e.g. protoplanetary disks, spiral galaxies). They are products of gravitational contraction and angular momentum conservation.  In a wide range of astrophysical systems, the spherical companion can be found inside the disk, including moonlets in Saturn's ring, planets in protoplanetary disks, and stars/black holes in AGN disks.  The companion-disk interaction determines the fates of these objects.  While most previous works focus on the simplest scenario that the orbit of the companion is coplanar with the disk, we start to explore how a misaligned companion can interact with the disk. The misaligned companion can torque the disk causing disk breaking, which may explain the broken protoplanetary disks discovered by ALMA and near-IR telescopes. The companion itself undergoes complex migration, which can be applied to stars/black holes in AGN disks, potentially related to binary BH formation and changing look AGN. 

Join via Zoom:
Meeting ID: 818 6692 9019

The colloquium is held in Feynman Lecture Hall, 201 E. Bridge.

For more information, please contact Denise Lu by email at [email protected].