* Astronomy

The hottest white dwarf in its class
A team of German and American astronomers present far-ultraviolet observations of white dwarf KPD 0005+5106 and reveal that it is among the hottest stars ever known with a temperature of 200 000 K at its surface. Astronomy & Astrophysics is publishing this discovery, which was made through spectroscopic observations with NASA's space-based Far-Ultraviolet Spectroscopic Explorer (FUSE).
Astronomy & Astrophysics is publishing spectroscopic observations with NASA's space-based Far-Ultraviolet Spectroscopic Explorer (FUSE) of the white dwarf KPD 0005+5106. The team of German and American astronomers who present these observations show that this white dwarf is among the hottest stars known so far, with a temperature of 200 000 K at its surface. It is so hot that its photosphere exhibits emission lines in the ultraviolet spectrum, a phenomenon that has never been seen before. These emission features stem from extremely ionised calcium (nine-fold ionised, i.e., CaX), which is the highest ionisation stage of a chemical element ever discovered in a photospheric stellar spectrum.

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