Researchers looked at dark clouds to find out how massive stars that are around eight times more massive than our Sun get so huge.
A research team used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to surveyInfrared Dark Clouds, which are some of the "darkest, coldest, and densest clouds" in the Milky Way in hopes of catching a glimpse of how these stars form, a National Radio Astronomy Observatory news release reported.
The cloud cores are so "massive and dense" that gravity should have already caused them to collapse and form a brand new Sun-sized star.
Since the core was starless, the researchers suggested there must be something "extra" supporting it.
"A starless core would indicate that some force was balancing out the pull of gravity, regulating star formation, and allowing vast amounts of material to accumulate in a scaled-up version of the way our own Sun formed," remarked Jonathan Tan, an astrophysicist at the University of Florida, Gainesville, and lead author of a paper published today in the Astrophysical Journal. "This suggests that massive stars and Sun-like stars follow a universal mechanism for star formation. The only difference is the size of their parent clouds."
Sun-sized stars start out as "hydrogen, helium, and other trace elements" inside a molecular cloud.
Once the newborn "kernel" of a star emerges gravity causes material to collapse in an accretion disk, which could eventually feed the formation of a new planet. Once a considerable amount of mass accumulates nuclear fission occurs, which turns the "kernel" into a full-blown star.
This explanation for star formation is fairly solid for Sun-sized stars, but cannot explain how massive stars grow.
"Some additional force is needed to balance out the normal process of collapse, otherwise our Galaxy would have a fairly uniform stellar population," Tan said. "Alternatively, there has been speculation that two separate models of star formation are needed: one for Sun-like stars and one for these massive stars."
The researchers looked into the dark clouds in hopes of finding an isotope called deuterium that would help them take the clouds' temperatures to determine if a star had been born. The presence of the isotope would indicate the cloud was cold, and no stars had formed there.
The team found "copious" amounts of deuterium, indicating the cloud was frigid and starless. This finding also suggests there is something supporting the core, which would buy enough time for a massive star to form. The team believes magnetic fields may be providing the extra support.
"These new ALMA observations reveal objects that are quite similar to the nurseries of Sun-like stars, but simply scaled-up by tens or a hundred times. This may mean that nature is more important than nurture when it comes to determining a star's size," Tan said.
