How big can a star get? Based on observations, astronomers think there's a limit of about 150 times the mass of the sun for the vast majority of stars.  

But a 2010 study turned up an exception—a star of 265 solar masses. Such very massive stars are interesting for more than their mass. These giants could expire in a special kind of explosion triggered by antimatter, known as a pair-instability supernova. They could also collapse to form an intriguing class of midsize black holes.  

Such massive stars may form in dense stellar clusters when multiple young stars collide and merge. Several nearby star clusters could harbor such stars, with masses of up to 600 suns. That’s according to astrophysicists who submitted their study to the Monthly Notices of the Royal Astronomical Society. [Tony Pan and Abraham Loeb,"Identifying Stars of Mass >150 Msun from Their Eclipse by a Binary Companion"]

They say that the way to find them is to look for very massive stars locked in binary pairings with another star. A partial eclipse of the larger star by its companion could potentially dim the entire star cluster enough for telescopes to detect it. A long shot, but worth a try. Because it’s always good to find a superstar.

—John Matson

[The above text is a transcript of this podcast.]