Carbon is an essential element of life in the Milky Way and other galaxies in the universe, and researchers have finally found one source of it in space: dying stars.
The Key Source of Carbon
According to a report by the University of California (UC), Santa Cruz, astronomers were able to analyze white dwarfs, which are the final stages of a star. Their research has supported the role of these tiny stellar beings as a key source of carbon.
Around 90% of stars in the universe become white dwarfs at the end of their life.
These stellar beings are very dense and gradually dim and cool down over a billion years, but before they take their final breath, dying stars leave their ashes into the cosmos and form the beautiful planetary nebulae we see thanks to the help of the Hubble Space Telescope (HST).
These ashes are rich with a variety of chemical elements, including carbon, and are then spread through the universe through stellar winds.
Although astronomers and scientists are very well aware that stars are the source of carbon in our galaxy, they are unsure which type of star provides this essential element for the creation of life.
Some astronomers believe the element comes mainly from massive stars that explode into a supernova.
Nevertheless, the new study, which was published this Monday, July 6, in the journal Nature Astronomy, favors the low-mass stars that become white dwarfs in the final stage of its life.
The study was a collaboration of an international team of astronomers who discovered and analyzed white dwarfs found in the open clusters of our universe or the areas that include a few thousand that were formed from the same molecular cloud and are around the same age.
The astronomers' team conducted the astronomical observation from which the recently published study was based at the W. M. Keck Observatory in Hawaii between August and September of 2018, according to Phys.org.
It was led by the study's co-author, Enrico Ramirez-Ruiz, a professor of astronomy and astrophysics from the University of California, Sta. Cruz.
"The findings pose new, stringent constraints on how and when carbon was produced by stars of our galaxy, ending up within the raw material from which the Sun and its planetary system were formed 4.6 billion years ago," said Jeffrey Cummings, an associate research scientist from John Hopkins University's Department of Physics and Astronomy and a co-author of the paper.
Breaking a Trend
Professor Ramirez-Ruiz explained how the team measured the masses of the white dwarfs by using the theory of stellar evolution and calculating their mass from birth.
Through their analysis, the team was able to find that white dwarfs from this open cluster have larger mass than previously believed, breaking a trend that if a white dwarf has a larger mass at birth, the more massive the white dwarf is at its death.
The team believes this explains how carbon from these low-mass stars ended up in the Milky Way.