Astrology

Astronomers find two debris rings around a white dwarf.

Astronomers have found two debris rings around a white dwarf, EarthSky reports, in what researchers describe as the first such double structure seen around this type of star. The rings circle J1328-1450 at different speeds, with a gap between them.

The researchers think two planetary bodies may have helped shape the rings after surviving part of the star's transformation, according to EarthSky. The Brighter Side of News reports that neither possible body has been detected directly.

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The gap points to possible survivors#

The team used the European Southern Observatory's Very Large Telescope in Chile to study J1328-1450, EarthSky reports. A white dwarf is the dense core left after a star exhausts its fuel and sheds its outer layers, according to The Brighter Side of News.

The gap led researchers to propose that two planetesimals, or small planetary bodies, survived near the star, UA.NEWS reports. The smaller candidate could be the size of a typical solar system asteroid or less. The larger one could fall between the moon and Pluto in size.

The proposed bodies may have escaped complete vaporization during the star's red giant phase, according to UA.NEWS. Lead author Nicola Gentile Fusillo of the University of Trieste said the system was the first known example combining two debris rings with two possible surviving planetesimals.

The rings preserve planetary material#

The team first noticed excess infrared light, a sign of dust around the star, The Brighter Side of News reports. An instrument called a spectrograph then separated the system's light by wavelength, revealing material reaching the star as well as gas orbiting it.

Calcium, oxygen, magnesium and iron were detected in the disk, according to UA.NEWS. The researchers think the material resembles the composition of rocky planets in the inner solar system. They also found chemical differences between the inner and outer parts, which they estimate could reflect at least two engulfed planets with different compositions.

The Brighter Side of News says the system offers a possible preview of the remains left by a star like the sun. According to EarthSky, the sun is expected to approach the end of its life in about 5 billion years. It would then spend about 1 billion years as an expanded red giant before eventually leaving a white dwarf.

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