Scientists Discover Biggest Star

Hugh Pickens writes "Scientists at the University of Sheffield have discovered the most massive stellar giant, R136a1 measured at 265 solar masses, using the European Southern Observatory's Very Large Telescope in Chile and data from the Hubble Space Telescope. It's in the Tarantula Nebula in the Large Magellanic Cloud, a small 'satellite' galaxy which orbits the Milky Way. Previously, the heaviest known stars were around 150 times the mass of the Sun, known as the 'Eddington Limit,' and this was believed to be close to the cosmic size limit because as stars get larger, the amount of energy created in their cores grows faster than the force of gravity which holds them together. 'Because of their proximity to the Eddington Limit they lose mass at a pretty high rate,' says Professor Paul Crowther, the chief researcher in the Sheffield team. Hyper-stars like R136a1 are believed to be formed from several young stars merging together, and are only found in the very heart of stellar clusters. R136a1 is believed to have a surface temperature of more than 40,000 degrees Celsius, and is 10 million times brighter than the Sun. Crowther adds that R136a1 is about as big as stars can get. 'Owing to the rarity of these monsters, I think it is unlikely that this new record will be broken any time soon.'"

Comments

Anonymous Coward

[Anonymous Coward]

I puzzled over this for a bit too, but this newly discovered star is the most massive discovered. The largest known star in terms of size is still VY Canis Majoris at ~2000 solar radii, but only ~20 times the mass of the Sun.

Link to research paper (arxiv)

[Octoploid]

Here is the link to the research paper: http://arxiv.org/abs/1007.3284

Re:Temperature on the surface of Sol

[Muad'Dave]

For anyone curious, as I was, what the surface temperature of our star is: 5500 degrees C

Which you can derive from noting the Sun's yellow color (approximately 570–590 nm) and applying Planck's Law or Wein's Displacement Law in reverse. Note that this pic shows the 5500 degree C peak aligns well with 500-600 nm.

From the Wein's Displacement article:

" * The surface temperature (or more correctly, the effective temperature) of the Sun is 5778 K. Using Wien's law, this temperature corresponds to a peak emission at a wavelength of 2.89777 million nm K/ 5778 K = 502 nm = about 5000 Å. This wavelength is fairly in the middle of the most sensitive part of land animal visual spectrum acuity. Even nocturnal and twilight-hunting animals must sense light from the waning day and from the moon, which is reflected sunlight with this same wavelength distribution. Also, the average wavelength of starlight maximal power is in this region, due to the sun being in the middle of a common temperature range of stars.

[See for example the article color, because of the spread resulting in white light. Due to the Rayleigh scattering of blue light by the atmosphere this white light is separated somewhat, resulting in a blue sky and a yellow sun]."

[Emphasis mine]

See also:

http://hypertextbook.com/facts/2002/TahirAhmed.shtml