How many types of stars live in other galaxies? It sounds like a simple question, but it’s hard to define because astronomers have a hard time estimating star clusters in distant galaxies.
A team of astronomers has now completed a count of more than 140,000 galaxies and found that the farthest galaxies tend to have heavier stars.
star count
Although astronomers do not have a complete count of the hundreds of billions of stars in the Milky Way, they have shown enough to get a good treatment of the population.
We know approximately how many small dwarf stars, how many Sun-like intermediate stars, and how many giant stars there are.
But repeat this exercise for other galaxies Too difficult. Most galaxies are too far away to identify and measure the individual stars within them.
We only see their brightest, heaviest stars, and we have to guess the smallest constellations.
Astronomers often assume that the demographics of a distant galaxy roughly match those we see in the Milky Way because, on average, galaxies should not be too different from each other.
Recently, a team of astronomers used the COSMOS catalog to study 140,000 individual galaxies, developing techniques for estimating the number of stars in each.
The research was conducted at the Center for Cosmic Dawn (DAWN), an international center for basic astronomy research with the support of the Danish National Research Foundation. DAWN is a collaboration between the Niels Bohr Institute at the University of Copenhagen and DTU Space at the Technical University of Denmark.
The future fate of the heaviest galaxies
“We’ve only been able to see the top of the iceberg and we’ve known for a long time that waiting for other galaxies to look like ours wasn’t a particularly good hypothesis. However, no one has been able to prove it. Galaxies form different groups of stars. study allowed us to do This can open the door to a deeper understanding of the formation and evolution of galaxies. ” Says Associate Professor Charles Steinhardt, co-author of the study.
The team found that, on average, distant galaxies tend to have larger stars than the Milky Way. On the other hand, nearby galaxies were relatively similar to ours.
“The mass of stars says a lot to astronomers. If you change the mass, you also change the number of supernovae and black holes that emerge from massive stars. As such, our result means that we will have to review many things that we previously assumed , because distant galaxies look very different from ours, “says Albert Sneben, a graduate student at the Niels Bohr Institute and first author of the study.
This work has several important implications.
First, astronomers can no longer assume the existence of a uniform group of stars when they look at distant galaxies, which represent the smallest galaxies in the universe. It also forces us to rethink How do galaxies evolve? over billions of years.
“Now that we are better able to decipher the mass of stars, we can see a new pattern; less massive galaxies continue to form stars, while more massive galaxies stop giving birth to new stars. This indicates a global trend marked by the death of galaxies, “concludes Snipin.
This article was originally published by universe today. Read the original article.