|Time:||星期四, 12月 10, 2020, 09:00am|
|Title:||Protoplanetary Disk Structure and Young Planet Population|
|Speaker:||Prof. Zhaohuan Zhu (UNLV)|
Online via Zoom (Meeting ID: 992 9825 3357 PW: 202012)
Recent ground based observations at various wavelengths reveal a variety of protoplanetary disk structures. These disk structures may help us to constrain the planet formation process. We apply the planet-disk interaction theory to substructures in the ALMA DSHARP sample to reveal the potential young planet population. We find that the occurrence rate for >5 M J planets beyond 5-10 au is consistent with direct imaging constraints. Disk substructures allow us to probe a wide-orbit planet population (Neptune to Jupiter mass planets beyond 10 au) that is not accessible to other planet searching techniques. On the other hand, ALMA surveys have suggested that the dust in Class II disks may not be enough to explain the averaged solid mass in exoplanets, under the assumption that the mm disk continuum emission is optically thin. This optically thin assumption seems to be supported by DSHARP observations where the measured optical depths are mostly less than one. However, we point out that dust scattering can considerably reduce the emission from an optically thick region. This optically thick disk scenario can solve several puzzles in protoplanetary disk observations and can provide enough dust to form exoplanets.
Prof. Zhaohuan Zhu got his B.S. from Peking University at 2005, completed his PhD in 2011 at the University of Michigan. Then he moved to Princeton as a Postdoctoral researcher and a Hubble Fellow. He joined UNLV as an assistant professor at 2016 and became an associate professor at 2020. His research interests are: Astrophysical Fluid Dynamics, Protoplanetary Disks, Star and Planet Formation, Disk Instabilities, Planet Detection, Planet Statistics. He received several awards including Sloan Research Fellowship and NSF Early Career Award.
Host: Xuening Bai