Article Posted on : - Nov 13, 2009

White Dwarf Star Spiral. Image Credit: NASA/Tod Strohmayer (GSFC)/Dana Berry (Chandra X-Ray Observatory)

NEW DELHI (BNS): Two earth sized bodies with oxygen rich atmospheres have been discovered but they are unusual white dwarf stars and not planets, according to astrophysicists at the University of Warwick and Kiel University.

The two white dwarf stars SDSS 0922+2928 and SDSS 1102+2054 are remnants of massive stars that are at the end of their stellar evolution having consumed all the material they had available for nuclear fusion, a report by Science Daily said.

"These surface abundances of oxygen imply that these are white dwarfs displaying their bare oxygen-neon cores, and that they may have descended from the most massive progenitors stars in that class," said astrophysicist Dr. Boris Gänsicke.

Theoretical models suggest that massive stars (around 7 -- 10 times the mass of our own Sun) will consume all of their hydrogen, helium and carbon, and end their lives either as white dwarfs with very oxygen-rich cores, or undergo a supernova and collapse into neutron stars.

Searching within an astronomical data set of the Sloan Digital Sky Survey (SDSS), the astrophysicists discovered the two white dwarfs with large atmospheric oxygen abundances.

The astrophysicists said, one possibility for the formation of SDSS 0922+2928 and SDSS 1102+2054 is that they descended from the most massive stars avoiding core-collapse, in which case they would be expected to be very massive themselves. However, they added that current data was insufficient to provide any unambiguous measure of the masses of these two unusual white dwarves.