A‍ team of astronomers, led by researchers at the Instituto de Astrofísica de Canarias (IAC), may have unraveled‌ the mystery behind the birth of ⁤some of the⁤ brightest and hottest⁤ stars in the cosmos, known as blue supergiants. These stars are at least 10,000⁣ times brighter, two ⁢to five times hotter, and 16 to 40 times more⁣ massive than the sun. Despite their ​extreme characteristics, ‌blue supergiants are commonly ​observed throughout the universe, which ‍has puzzled scientists ⁢for decades.

The Mystery of Blue Supergiants

Blue supergiants are often found alone, without a gravitationally bound companion ⁤star. This is unusual as the more massive a star is, the more likely ‍it is ‍to have a​ companion. Around 50%​ of stars⁢ the size of the sun have a companion, but⁢ around 75% of much more massive stars are accompanied. However, ‌blue supergiants, some of the⁣ most massive stars, are⁤ lonely. The⁢ reason for⁤ this may be that blue supergiant stars‌ exist in systems in ⁢which‌ the occupants have⁢ already spiraled together, collided, ⁣and merged.

Investigating​ the Origins

The ​team of scientists set about investigating this by analyzing 59 early B-type blue supergiants located in the Large Magellanic ⁢Cloud, a satellite⁢ galaxy of the Milky Way, and creating novel ⁢stellar simulations. “We ​simulated the mergers of evolved giant stars with their smaller‍ stellar‍ companions over a wide range of parameters, taking into⁣ account the interaction and mixing ​of the two stars⁤ during the merger,” said study leader and IAC researcher Athira Menon.

Findings and Implications

The team’s findings suggest that‌ blue supergiants ⁤slip into an‌ evolutionary gap in conventional ​stellar physics ⁢— a phase of stellar evolution where astronomers would not ​expect‌ to see stars.⁤ “Remarkably, we⁣ found that stars born from such mergers have greater success in ⁣reproducing the surface composition, particularly the nitrogen and helium ⁣enhancement, of a large fraction of the sample than ‍conventional‌ stellar models,” said team member and IAC researcher Danny Lennon.‌ “This ⁤indicates that mergers ⁤may be the dominant channel to produce blue⁣ supergiants.”

The new ​results could represent a large step‌ toward solving a lingering problem regarding the ⁣birth of‍ blue supergiant stars, also indicating‍ the importance of binary star mergers in shaping the ⁢stellar populations and overall​ shapes of galaxies.

Future Research

The next step ​in ⁢this research ⁣will see‌ the team switch attention from the ​birth of ‌blue supergiant stars to the death of these massive objects. The ⁤scientists will investigate how the supernova explosions of blue ⁤supergiant⁢ stars create neutron stars and​ black holes.