Heavyweight Stars Much More Common Than Previously Thought

An international team of researchers has recently concluded a groundbreaking study, which has revealed a far greater abundance of massive stars in one of the Milky Way’s satellite galaxies than scientists previously thought was possible.

The discovery was made by ‘weighing’ stars in the Large Magellanic Cloud, a satellite galaxy approximately 160,000 light years away. The researchers say that the results have huge implications for our understanding of star and galaxy formation. Because each stage in the formation of stars and galaxies takes many billions of years, we are unable to watch them unfold. Instead, we rely on indirect methods of ascertaining their lifecycles. By looking at stars and galaxies at different stages of their lives, we can begin to piece together how they might get from one point to another. If you would like to find out more about astronomy, keep an eye on the Science & Tech section of CapitalWired.com.

Rare Stars

Usually, no matter where in the universe we point our telescopes, we find that massive stars (those with a mass 15-200 times greater than that of our Sun) are rare. In fact, it was previously thought that these massive stars could account for no more than 1% of all the stars in the universe, but this new study has thrown that figure into doubt. Because these massive stars are so rare, we have had relatively few opportunities to study them.

By focusing their attention on a particular area of the Large Magellanic Cloud, an area designated as 30 Doradus, which was already known to host some of the most massive stars that we know of, the researchers were able to make an unexpected discovery. The team used a number of new observational, theoretical, and statistical techniques. The large sample that they used allows them to make the most accurate measurements of the properties of high-mass stars that have been possible to date.

Why Does It Matter?

Stars, even small ones, are big objects which have a significant impact on their environment. A star’s gravity is able to support planet formation and the stable orbits of those planets. The bigger the star, the bigger its gravitational effect and the area it affects. The mass of a star also determines its life cycle, larger high-mass stars will burn through the fuel in their cores at a much faster rate and thus have a shorter lifespan. Larger stars also undergo more violent events at the end of their lives. The very biggest stars will collapse into black holes, objects which have a profound impact on the universe around them. If there are, and have been, more massive stars than we previously thought, this means that we will need to rethink our assumptions about how our local galaxies got to their current state.

The Future

These latest results, therefore, have potentially far-reaching consequences for our understanding of cosmology. If the latest results stand up to the peer review process, then we could well live in a universe with 70% more supernovae (the violent explosions which occur at the end of a star’s life) than previously thought. Supernovae play a crucial role in triggering further star formation, it is also these explosions which allow elements heavier than helium to spread through the universe.

The results of this research open many questions and new avenues for future research. Science is always most exciting when what we thought to be unequivocally true is proven false.


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