Scale drawing of the size of R136a1 (darker blue) in comparison to a Sun-like star (yellow) and the previously believed ‘biggest star’ (light blue).
Credit: ESO/M. Kornmesser
SYDNEY: Astronomers have discovered a mammoth star in a nearby galaxy that is 300 times the mass of the Sun and 10 million times brighter, easily breaking all the records.
The record-breaking star was discovered using a collection of data from the European Southern Observatory's (ESO) Very Large Telescope and from NASA.
A team of scientists led by astrophysicist Paul Crowther from the University of Sheffield in England reported their findings in the Monthly Notices of the Royal Astronomical Society.
Breaking the limit two times over
Small stars are well documented and the lower limit for small stars in close to 0.1 solar mass. The mass of large stars is less definite, but until now it was believed that around 150 solar masses is the largest a star can be.
When they discovered the mammoth star, Crowther and his team were studying a cluster of stars – where stars are born – called RMC 136a, located in the Tarantula Nebula. The star, 'R136a1', has a mass of 265 solar masses, which means it's birth solar mass would be closer to 320 solar masses, as stars lose mass as they age.
R136a1 not only supersedes the Sun in mass but it's surface temperature measure at over 40,000 degrees, several times hotter than the Sun, which, along with its mass makes the newly discovered star millions of times brighter than the Sun as well.
Birth and death of big stars remain a mystery
If this new star replaced our Sun, the intensity of its ultraviolet radiation would not only kill humans but it would sterilise Earth.
"Understanding how very big stars form remains a challenge", said Crowther. At the moment astronomers are unsure whether mammoth stars are either born big or smaller stars combine to make one big star.
The researchers do not know what will happen when the star dies. When any star between eight to 150 solar masses uses up all its fuel, they explode as a supernovae resulting in either a black hole or a neutron star.
Tip of the iceberg
Current theory suggests that when a star with a mass over 150 dies, they "end their life with a bigger bang, exploding as very bright 'pair production supernovae' but not leaving behind any remnant. They completely blow themselves to bits", said Crowther.
R136a1 is already middle-aged: it's a little over a million years old. Already it has shed a fifth of its initial mass over that time, or more than 50 solar masses, the researchers said.
Brian Schmidt, an astronomer at Australian National University, expects that the discovery of this mammoth star is only a taste of things to come, as the study "looked at a relatively modest nearby galaxy and there are most certainly even more massive stars out across the universe".
"How massive can a star be is one of the fundamental questions facing astronomy, primarily because the bigger a star is, the brighter it shines, the shorter its life is, and the more spectacular it explodes", says Schmidt.
The caption is totally wrong
The caption depicts a blue dwarf as being the "largest previously known star? Come on, I thought this was a science blog?????
Antares and Betelgeuse are MUCH larger, being only 15-18x the mass of the sun, but Betelgeuse has a radius that extends past the orbit of Mars.
a "blue dwarf" is still a main sequence star and would only be marginally larger than the sun.
Your replacement star is ready for delivery
I am more worried about their threat of what will happen if this star replaces our own.
Hey
Mass has little to do with area or radius of star as that winner goes to VY canis majoris at 1.7 billion miles radii
Clean again?
haha sterilise, sounds like we need a bath