2023-09-29 04:00:06
A team of researchers led by Ma Yingxiu, a doctoral student at the Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences (CAS), has identified a new hub-filament system in a molecular cloud. This system, named G323.46-0.08, is a crucial clue to understanding the formation of high-mass stars.
Map of G323.46-0.08 showing different colors to indicate the speed at which the gas 13CO is moving.
Credit: Astronomy & Astrophysics (2023)
In a molecular cloud, a hub-filament is composed of a dense central hub surrounded by filaments. The filaments are channels that carry gas from the extended cloud toward the hub. Once in the hub, these gases are likely to aggregate into high-mass stellar clusters.
Ma Yingxiu and his team observed that the G323.46-0.08 system consists of three sub-filaments named F-north, F-west and F-south. The central hub is occupied by a high-mass cluster called AGAL323.459-0.079. Gas is transported to this central cluster mainly by the F-west and F-south subfilaments.
The minimum aggregation rate has been estimated at 1,216 solar masses per million years. This aggregation supplies the central cluster with materials necessary for the formation of new stars. In the hub, the gas velocity gradients show a V-shaped structure, a sign of an acceleration of gas movements due to gravitational collapse.
The researchers also determined the parameters of the gravitational collapse model that apply to the G323.46-0.08 system. The hub mass varies between 1000 and 1500 solar masses, consistent with the observed mass of 1100 solar masses for AGAL323.459-0.079.
“Our results strongly support the theory of global hierarchical collapse,” said Ma Yingxiu.
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