A giant white dwarf star may be the offspring of a collision between two other white dwarfs, a new study finds.
Oddball giant white dwarf may have formed in epic crash of smaller stars : Read more
"The researchers knew WDJ0551+4135 had a strange composition, a mass twice that of the average white dwarf and an age that seemed relatively young if one looked at the star's heat but relatively old if one looked at its motions. The astronomers realized that one event could explain all of these mysteries: WDJ0551+4135 formed when two white dwarfs collided, heating the resulting white dwarf and restarting its cooling process.
"Although there is lots of evidence that such mergers occur, including examples in distant galaxies, actually picking out a white dwarf and saying this one here is from a merger is quite hard," Hollands said. "This is only one of a handful of cases where it's been possible to do that and the only one identified through its composition."
The scientists said that the merger occurred about 1.3 billion years ago. But that event reset WDJ0551+4135's cooling age, making it difficult to determine the ages of the two original white dwarfs, which could have been many billions of years old."
My observation. This is an interesting method of reconciling what appears to be conflicts in dating the white dwarf (WD) according to stellar evolution theory. If the merger did not take place 1.3 billion years ago, the dating reconciliation for the WD age calculated has problems.