Discovery of an ultra-young stellar “snake” with two dissolving cores in the solar neighborhood. (arXiv:2005.12265v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tian_H/0/1/0/all/0/1">Hai-Jun Tian</a>
In this Letter we report the discovery of an ultra-young (only 30-40,Myr)
quasi-tidal tail (dubbed a stellar “snake”) nearby the region of Orion complex
from {it Gaia} DR2. The average distance of this structure is about 310,pc
from the Sun. Both the length and width are over 200,pc, but the thickness is
only about 80,pc. Oddly it has only one tail. Its head includes two dissolving
cores, which can be clearly distinguished in the 6D phase space. The two cores
are probably broken from an open cluster of initially thousands of members with
a total mass of larger than 2000$M_{odot}$ in the same stellar population.
This population is so young (an order of magnitude younger than the ages of any
previously known tidal tails) that it can not be well explained with the
classical theory of tidal tails. In addition, we check the theory of mass
segregation, but do not find any strong evidence for this theory within 125,pc
from the cluster center. Our finding challenges the current theory of the
formation and evolution of tidal tails. Its age is well consistent with the
history of the Gould Belt. So it may fill the observational gap between the
history of the Gould Belt and the star formation near the Orion complex.
In this Letter we report the discovery of an ultra-young (only 30-40,Myr)
quasi-tidal tail (dubbed a stellar “snake”) nearby the region of Orion complex
from {it Gaia} DR2. The average distance of this structure is about 310,pc
from the Sun. Both the length and width are over 200,pc, but the thickness is
only about 80,pc. Oddly it has only one tail. Its head includes two dissolving
cores, which can be clearly distinguished in the 6D phase space. The two cores
are probably broken from an open cluster of initially thousands of members with
a total mass of larger than 2000$M_{odot}$ in the same stellar population.
This population is so young (an order of magnitude younger than the ages of any
previously known tidal tails) that it can not be well explained with the
classical theory of tidal tails. In addition, we check the theory of mass
segregation, but do not find any strong evidence for this theory within 125,pc
from the cluster center. Our finding challenges the current theory of the
formation and evolution of tidal tails. Its age is well consistent with the
history of the Gould Belt. So it may fill the observational gap between the
history of the Gould Belt and the star formation near the Orion complex.
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