Title: The Stellar "Snake" and the Related Sciences

Speaker: Professor Haijun Tian (Hangzhou Dianzi University)

Time: 9:30am, December 18, 2023

Location: 5-516, PMO Xianlin Campus

Abstract: In 2020, we reported the discovery of a young (only 30-40 Myr) snake-like structure (dubbed a Stellar “Snake”) in the solar neighborhood from Gaia DR2. The average distance of this structure is about 310 pc from us. Both the length and width are over 200 pc, and the thickness is about 80 pc. The “Snake” has one tail and two dissolving cores, which can be clearly distinguished in 6D phase space. The population is so young that it cannot be well explained with the classical theory of tidal tails. We therefore suspect that the “Snake” is hierarchically primordial, rather than the result of dynamical tidal stripping, even if the “snake” is expanding. In 2022, we extended the size of the “Snake” to more than two times its length, making the number of its member candidates totaling to over ten thousand. This finding will provide us an ideal test bed to study the stellar formation and evolution in cluster environments with one uniform population.

In this talk, I will present a panoramic view on the structure and properties of the “Snake”, and demonstrate several science cases of the “Snake” we are developing recently.