European astronomers have obtained the best images ever of an unusual double star, where the companion star is a vampire, according to a press release from European Southern Observatory (ESO).
Wide-field image of the sky around SS Leporis (ESO/Digitized Sky Survey 2/Davide De Martin)
Astronomers created a virtual telescope 130 metres across by combining the light captured by four telescopes at the Paranal Observatory. They observed the system SS Leporis in the constellation of Lepus, which contains two stars that circle around each other in 260 days. The results show that the transfer of mass from the primary star to the companion in this double system is surprisingly gentler than expected.
“We can now combine light from four telescopes and create super-sharp images much more quickly than before,” said Nicolas Blind of IPAG, France, the lead author on the paper published in the journal Astronomy & Astrophysics.
“The images are so sharp that we can not only watch the stars orbiting around each other, but also measure the size of the larger of the two stars.”
Images of the double star system SS Leporis (ESO/PIONIER/IPAG)
“We knew that this double star was unusual, and that material was flowing from one star to the other,” said Henri Boffin from ESO, co-author on the paper. “What we found, however, is that the way in which the mass transfer most likely took place is completely different from previous models of the process. The bite of the vampire star is very gentle but highly effective.”
The new observations are sharp enough to show that the giant star is smaller than previously thought, making it much more difficult to explain how the red giant lost matter to its companion. The astronomers now think that, rather than streaming from the primary star to the companion, the matter must be expelled from the giant star as a stellar wind and captured by the hotter companion.
