Odd names aside, IRAS 17163-3907 is a genuine curiosity, the European Southern Observatory (ESO) said on Wednesday.
It is a monster of a star, with a diameter 1000 times bigger than the Sun and 500,000 times the brightness.
Yellow hypergiants are extremely rare because they are in what is known as the '"yellow void", which occurs for stars of this type in spectral classes F and G (mostly G). At the temps in these spectral classes, hypergiants become thermodynamically unstable and the stars either shrink to become LBV's/blue hypergiants or expand and cool to become red hypergiants (in rare cases). It's also characteristic for these stars (yellow hypergiants) not to exceed 500000 solar luminosities. A good esxample of one is Rho Cassiopeiae.
Last edited by renormalised; 01-10-2011 at 01:50 PM.
