New observations of a white dwarf show that this fireball has a surface temperature of 250000 degrees Celsius (482,000 Fahrenheit), which is 2.5 times hotter than a typical stellar residue. Moreover, scientists have discovered a dwarf life on the edge of the Milky Way, contrary to previous studies.
New observations in the ultraviolet spectrum, made with the Hubble Space Telescope, suggest that this star is five times more massive than our Sun. Scientists do not know how this star could reach such a temperature, so it is necessary to carefully analyze its composition.
“The strangest thing about this white dwarf (and its twin, H1504 + 65) is its surface composition,” wrote study lead author Klaus Werner of the University of Tübingen in Germany. "It has carbon and oxygen without hydrogen and helium. Currently, there is no suitable explanation for this phenomenon. As a rule, hydrogen or helium dominates white dwarfs." About RX J0439.8-6809 only a little is known. It seems that the temperature of the star reached more than 400,000 degrees Celsius about 1,000 years ago. It was seen due to x-ray images about 20 years ago, but it was originally thought that it was located in the Large Magellanic Cloud, a galaxy outside our own.
"Future X-ray studies combined with optical data can help scientists study this white dwarf with an unusual surface composition," Werner added. "The search for trace elements (and other metals) may give a hint at the evolution of the star."
The study was recently published in the journal Astronomy and Astrophysics.