Thursday, 22 July 2010

Your R136a1 is so fat...

Any regular news readers would have been hard-pressed to miss the news that the largest star to date has been discovered, our new friend, R136a1. Using the ESO Very Large Telescope and archival Hubble data, researchers at the University of Sheffield isolated a star that is 265 times the mass of the Sun, a million times brighter and a birthweight about 320 times the Sun's.

Paul Crowther, Professor of Astrophysics at the University of Sheffield studied two young clusters of stars, NGC 3603 and RMC 136a, both clusters of young, hot, massive stars. The interesting thing about this is that this discovery completely dwarfs previous knowledge that stars were limited in their mass by about 150 times the mass of the Sun. Within R136, only four stars weighed more than 150 solar masses at birth, yet they account for nearly half of the wind and radiation power of the entire cluster, comprising approximately 100 000 stars in total.

Comparing R1361a to the Sun, the brightness is about the difference between the Sun and the full moon. Imagine now that we simply replaced the Sun with R136a1, “Its high mass would reduce the length of the Earth's year to three weeks, and it would bathe the Earth in incredibly intense ultraviolet radiation, rendering life on our planet impossible,” says team-member Raphael Hirschi from Keele University.The relative sizes of different stellar classifications are shown below:

The important thing to take away from this discovery is that this is simply the dynamics of scientific research. In the same way the Kuiper Belt forced us to redefine our Solar System and Pluto's classification, this forces us to redefine our understanding of stellar evolution and dynamics. I am inclined to agree with astronomer royal Martin Rees (who can't? With such stellar *ahem* eyes and a devil-may-care smirk...) in his assessment that this is a cool discovery and it's great that it involves UK science and advanced telescopes, but it is not Earth-shattering. It just makes us appreciate the ever-changing understanding of the universe around us.


  1. I love how this star owns VY Canis Majoris. The largest kids on the block, just got shown up. Big time.

  2. I can't wait until we get back to the very first Pop. III (or is it IV?) stars that ended the Dark Ages. They don't make stars like that anymore...

    But for reals - this star must have been the result of at least a few mergers. It's hard to imagine a star this size being able to form otherwise. It's all about losing that pesky angular momentum. What's really fun to think about is what the lifetime is - should be only a few hundred thousand to a million years!