Call it the interstellar version of The Walking Dead: Researchers from the University of Warwick in England have captured the first-ever image of a white dwarf tearing apart an asteroid that was unfortunate enough to have wandered too close to the dead (or is that undead?) star.
As the white dwarf rips apart the rocky object, it creates a glowing ring composed of debris and dust particles, Christopher Manser of the Warwick Astrophysics Group and colleagues explained in a paper published in the Monthly Notices of the Royal Astronomical Society.
The asteroid’s proximity to the star results in it being shredded by the white dwarf’s gravity, and gases produced by collisions among debris within the ring are illuminated by ultraviolet rays from the star itself. This activity causes it to emit a dark, red glow, which Manser’s team detected and used to create the newly-released image of the ring.
“The image we get from the processed data shows us that these systems are truly disc-like, and reveal many structures that we cannot detect in a single snapshot,” said Manser, a Ph.D. student at the university. “The image shows a spiral-like structure which we think is related to collisions between dust grains in the debris disc.”
Detailed pictures were “worth the wait”
Manser and his fellow astronomers were investigating the remnants of a planetary system around the white dwarf star SDSS1228+1040, and while similar debris rings have been discovered around a handful of other dead stars, the imaging of this particular white dwarf provided new insights into the structure of these systems—in part because of the scale of the system.
In fact, as Manser pointed out, “The diameter of the gap inside of the debris ring is 700,000 kilometers, approximately half the size of the Sun, and the same space could fit both Saturn and its rings, which are only around 270,000 km across. At the same time, the white dwarf is seven times smaller than Saturn but weighs 2500 times more.”
While researchers have known about these debris disks for more than two decades, they only now have been able to obtain an image of one thanks to Doppler tomography, a technique that scans objects from multiple angles and combines them into a single image on a computer. The method is not unlike the CT scans frequently used in hospitals.
“When we discovered this debris disk orbiting the white dwarf SDSS1228+1040 back in 2006, we thought we saw some signs of an asymmetric shape. However, we could not have imagined the exquisite details that are now visible in this image constructed from twelve years of data,” said Warwick professor Boris Gänsicke. “It was definitely worth the wait.”
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Feature Image: Mark Garlick/University of Warwick
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