Star Clusters Triggered by GS242-03+37

AbstractWe explore the Milky Way supershell GS242-03+37. We argue that the observed HI distribution can be explained as an expanding structure about 100 Myr old powered with a modest energy released by an OB association. The formation of star clusters has been triggered less than 30 Myr ago when the ISM density in the supershell increased due to the galactic differential rotation. The observed age sequence of young star clusters is related to the evolution of the column density during the supershell expansion.

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Fourth Day of Creation: The Proto-history of Young Stars, Star Streams, and Exoplanets Near the Sun

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315006511 ◽

2015 ◽

Vol 10 (S314) ◽

pp. 1-7

Author(s):

Virginia Trimble

Keyword(s):

Star Formation ◽

Milky Way ◽

Star Clusters ◽

Young Star ◽

Young Stars ◽

The Sun ◽

Complex Processes ◽

History Of ◽

Moving Groups ◽

Young Star Clusters

AbstractItems of scientific knowledge at any moment in time have pre-histories when they were debated, doubted, or absolutely denied. The examples considered here are the admitted facts that star formation is an on-going process in the Milky Way, that there are young moving groups (the products of young star clusters in the process of dissolution and perhaps more complex processes), and that planets orbiting other stars are common. It is hard to imagine any of these ceasing to be part of core astronomical knowledge, but you are advised not to place large bets on this.

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GS242-03+37: a lucky survivor in the galactic gravitational field

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832918 ◽

2018 ◽

Vol 619 ◽

pp. A101 ◽

Cited By ~ 2

Author(s):

S. Ehlerová ◽

J. Palouš

Keyword(s):

Star Formation ◽

Milky Way ◽

Star Clusters ◽

Young Star ◽

Stellar Winds ◽

Supernova Explosions ◽

High Velocity Clouds ◽

Shell Approximation ◽

Hi Shells ◽

Young Star Clusters

Context. HI shells and supershells, found in discs of many galaxies including our own, are formed by the activity of young and massive stars (supernova explosions and stellar winds), but the formation of these structures may be linked to other energetic events, such as interactions of high-velocity clouds with the galactic disc. The larger structures in particular significantly influence their surroundings; their walls are often places where molecular clouds reside and where star formation happens. Aims. We explore the HI supershell GS242-03+37, a large structure in the outer Milky Way. Its size and position make it a good case for studying the effects of large shells on their surrounding. Methods. We perform numerical simulations of the structure with the simplified hydrodynamical code RING, which uses the thin-shell approximation. The best fit is found by a comparison with the HI data and then we compare our model with the distribution of star clusters near this supershell. Results. The best model of GS242-03+37 requires, contrary to previous estimates, a relatively low amount of energy, and it has an old age of ∼100 Myr. We also find that the distribution of young star clusters (with ages <120 Myr) is correlated with walls of the supershell, while the distribution of older clusters is not. Clusters that have the highest probability of being born in the wall of the supershell show an age sequence along the wall. Conclusions. GS242-03+37 is a relatively old structure, shaped by the differential rotation, and its wall is a birthplace of several star clusters. The star formation started at a time when the supershell was not already supersonically expanding; it was a result of the density increase due to the galactic shear and oscillations perpendicular to the disc of the Milky Way.

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