Astronomers utilizing the Hubble House Telescope have found {that a} seemingly bizarre white dwarf star is definitely the results of a dramatic stellar merger.
This consequence, detailed in a brand new research led by Snehalata Sahu and Boris Gaensicke of the College of Warwick within the U.Ok., means that different “normal-looking” white dwarfs scattered all through the universe might even have violent pasts.
“It is a discovery that underlines issues could also be completely different from what they seem to us at first look,” Gaensicke, research co-author and a professor of physics on the College of Warwick who serves because the principal investigator of the Hubble program, mentioned in a assertion. “Till now, this appeared as a traditional white dwarf, however Hubble’s ultraviolet imaginative and prescient revealed that it had a really completely different historical past from what we’d have guessed.”
The star, named WD 0525+526, is positioned about 128 light-years from Earth. Although it appeared moderately normal at first look via seen mild, additional observations utilizing the Hubble telescope revealed telltale indicators of a extra turbulent origin, the brand new research studies.
Nevertheless, WD 0525+526 could have adopted a really completely different path. As a substitute of forming from one dying star, it seems to have emerged from the violent collision and merger of two stars. This dramatic previous, the brand new research says, left delicate however detectable fingerprints within the white dwarf’s atmospheric make-up.
When Gaensicke and his group examined WD 0525+526 with Hubble’s ultraviolet devices, they detected an uncommon quantity of carbon within the star’s environment — a key signal the star was shaped in a merger.
Usually, white dwarfs have outer layers of hydrogen and helium that obscure their carbon-rich cores. However in mergers reminiscent of this one, the extraordinary collision can strip away a lot of those outer layers, permitting carbon to rise to the floor. The alerts of such stars are tough to detect in seen mild, however turn out to be clearer in ultraviolet wavelengths — and that is the place Hubble excels.
WD 0525+526 is outstanding even among the many small variety of white dwarfs recognized to be merger remnants, in line with the assertion. It has a floor temperature of practically 21,000 Kelvin (about 37,000 levels Fahrenheit) and a mass 1.2 occasions that of the solar, making it each hotter and extra huge than others on this uncommon class, the research notes.
As a result of WD 0525+526 appeared fully regular in seen mild, astronomers now suspect that many extra white dwarfs may very well be hiding related explosive origins.
“We wish to prolong our analysis on this subject by exploring how widespread carbon white dwarfs are amongst related white dwarfs, and what number of stellar mergers are hiding among the many regular white dwarf household,” Antoine Bedrad, a researcher on the College of Warwick who co-led the research, mentioned within the assertion.
“That can be an essential contribution to our understanding of white dwarf binaries, and the pathways to supernova explosions.”
This analysis is described in a paper printed Aug. 6 within the journal Nature Astronomy.
