How White Dwarfs shows humans the origins of Carbon in the universe
By: Luke Wang
Hovering in the massive universe in which we also live in are many stars, just like the sun that supplies us with energy. Approximately 90 percent of these stars end their lives as White Dwarfs, which are very dense stellar remnants that “gradually slow and dim over billions of years.”
The legacy of these stars are both important and amazing. The ashes of these White Dwarfs will be carried around the universe with the help of stellar winds. The stellar winds are normally enriched with chemical elements, including carbon.
Scientists know that every bit of carbon in the universe was created by stars through the fusion of three helium nuclei. This sparked debates in the astrophysicists about whether stars are the main source of carbon in the galaxy, especially our own galaxy, the Milky Way.
However, there have been strong improvements in the research done on the White Dwarfs. The initial mass of these stars and their final mass as White Dwarfs are known as “initial-final mass relation.” Recent analysis have shown that White Dwarfs in open clusters are larger than expected, giving them a “kick” or “boost” in their initial-final mass relation.
This unusual outcome is caused by the movement of carbon in the body of these White Dwarfs, newly produced carbon is transported to their surface mantles and carried away by gentle stellar winds. This allowed the core of the stars to grow in size. Researchers measured that stars that had more than 1.5 solar mass were able to contribute to an galactive level of carbon enrichments while stars with less than 1.5 solar mass were not.
With this new information, scientists were able to determine now that large stars that have a solar mass larger than 1.5 are the main contributors of carbon to our universe. Scientists such as Pier-Emmanuel Tremblay were able to conclude from this new discovery that “it impacts the age of known white dwarfs, which are essential cosmic probes to understand the formation history of the Milky Way. The initial-to-final mass relation is also what sets the lower mass limit for supernovae, the gigantic explosions seen at large distances and that are really important to understand the nature of the universe."Hopefully, this new discovery can allow more improvements in the steps of discovery in Space.