A supernova lies near the stream of matter pulled out of the lower galaxy after a close pass with the upper one (Image: F Patat/ESO)
A supernova has been spotted near a pair of wrestling galaxies in a new image from the Very Large Telescope. The star appears to have detonated in deep space, after being flung out of one of the violently interacting galaxies.
The supernova was found in the vicinity of two galaxies that lie 87 million light years away in the constellation Libra. One, called MCG-01-39-003 (lower right), has a mangled appearance, with a long stream of matter trailing away from it.
The stream was pulled out by the gravity of a galaxy called NGC 5917 (upper right), which must have passed nearby in the past.
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The supernova, called SN 2005cf, was discovered in progress on May 28, 2005. It was found by the Katzman Automatic Imaging Telescope, a robotic supernova-hunting instrument outside of San Jose, California, US.
Stripped out
From the relatively crude discovery image, the supernova appeared to be part of the stream of matter coming from the lower galaxy.
But a higher resolution view from the European Southern Observatory’s VLT in Paranal, Chile, showed otherwise.
“Curiously, the supernova appears to be outside of the tidal tail,” says ESO astronomer Ferdinando Patat, who carried out the observations. “The progenitor system was probably stripped out of one of the two galaxies and exploded far away from the place where it was born.”
The supernova is classified as a type Ia. These happen in binary star systems, where a compact star called a white dwarf steals gas from an ordinary companion star. Eventually the rising pressure and temperature of the white dwarf trigger a runaway nuclear reaction, destroying the star in a colossal explosion.
The image was made by combining multiple exposures taken by the VLT in April and May 2006.
