SCIENCE FILE : Scientists find a new type of star
Scientists have added a new member to the stellar zoo, a type of white dwarf star that had been long predicted but never before found.
White dwarfs are end-of-life stars that have burned up most of their nuclear fuel and shrunk to the size of Earth. Other stars shrink further, collapsing into neutron stars smaller than Los Angeles.
The new type of star, called an oxygen-rich white dwarf, is a kind of “missing link” between the so-called normal white dwarfs and neutron stars, according to study coauthor Boris Gaensicke, a physicist at the University of Warwick in Britain. Two of the stars have been found so far, according to the team’s research, published in the journal Science Express.
“The discovery of these stars is really exciting for the field, as literally thousands of white dwarfs are known, but so far none [until now] with oxygen-rich atmospheres,” Gaensicke said in an e-mail.
The new white dwarfs were found by researching the extensive Sloan Digital Sky Survey of stars. Gaensicke said that the importance of finding these two stars (named SDSS 0922+2928 and SDSS 1102+2054 and located about 400 and 220 light-years from Earth) is that they could help explain why some stars become white dwarfs while others collapse into neutron stars.
Scientists believe that stars ranging from seven to 10 times the mass of the sun are candidates for ending their lives as white dwarfs or neutron stars. The exact boundary between these two fates “is not very well determined,” Gaensicke said.
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