According to NASA in Spanishthese are the first data published from a project called EWOCS, led by astronomers from Italy’s National Institute of Astrophysics in Palermo. As part of EWOCS, the Chandra observed Westerlund 1 for about 12 days in total.
In a very bright supercluster
Currently, only a handful of stars form in our galaxy each year, but in the past the situation was different. The Milky Way used to produce many more stars, probably reaching its peak output of tens or hundreds of stars per year about 10 billion years ago and then gradually declining since then. Astronomers believe that most of this star formation took place in massive star clusters, known as “super star clusters“, as Westerlund 1. These are young star clusters containing more than 10,000 times the mass of the Sun. Westerlund 1 is between 3 and 5 million years old.
This new image shows the new deep data of the Chandra together with previously published data from Hubble Space Telescope from NASA.
X-rays detected by Chandra show young stars (mainly represented in white and pink) as well as heated diffuse gas throughout the cluster (colored in pink, green and blue, in order of temperature increase for the gas). Many of the stars captured by Hubble appear as yellow and blue dots.
Only a few superclusters of stars still exist in our galaxy, but they offer important clues about this earlier era when most of our galaxy’s stars formed.
Westerlund 1 is the largest of these remaining superclusters of stars in the Milky Way. and contains a mass between 50,000 and 100,000 times that of the Sun. It is also the closest superstar cluster to Earth at about 13,000 light years.
These qualities make Westerlund 1 an excellent target for studying the impact of a superstar cluster’s environment on the process of star and planet formation, as well as the evolution of stars over a wide range of masses.
This new set of Deep data from Westerlund 1’s Chandra has more than tripled the number of known X-ray sources in the cluster. Before the EWOCS project, Chandra had detected 1,721 sources in Westerlund 1. The EWOCS data found almost 6,000 X-ray sources, including fainter stars with masses less than the Sun. This gives astronomers a new population to study.
One revelation is that 1,075 stars detected by Chandra are compressed in the center of Westerlund 1, within a radius of four light years from the center of the cluster. To get an idea of how crowded this is, four light years is about the distance between the Sun and the closest star to Earth.
The diffuse emission seen in the EWOCS data represents the first detection of a halo of hot gas surrounding the center of Westerlund 1, which astronomers believe will be crucial to assessing the formation and evolution of the cluster, and to providing a better estimate. requires its mass.
This entry was published in News on June 11, 2024 by Francisco Martín León
