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Astronomers have found a planet that could support life

A new study led by University College London (UCL) has recently identified a ring of planetary debris with moon-size structures orbiting a white dwarf star located 117 light years away from the Earth. The scientists believe that these 65 evenly spaced clouds of planetary debris that are orbiting the white dwarf every 25 hours could be kept in such a precise arrangement by a nearby planet located in the “habitable zone” of the star, where the temperature may be right for water and thus life to exist. This is the first time that a potentially life-supporting planet has been found orbiting a white dwarf.

While very large stars become black holes when they die, smaller ones such as our Sun become white dwarves – stars that have burned through all their hydrogen fuel and lost their outer layer. They are usually the size of a planet and emit a bluish-white light after they are formed. By using data from ground- and space-based telescopes, an international team of researchers measured light from a white dwarf in the Milky Way known as WD1054-226 and, to their surprise, found pronounced dips in light corresponding to the 65 clouds of planetary debris orbiting the star.

“The moon-sized structures we have observed are irregular and dusty (e.g. comet-like) rather than solid, spherical bodies. Their absolute regularity, one passing in front of the star every 23 minutes, is a mystery we cannot currently explain,” said study lead author Jay Farihi, a professor of Astrophysics at UCL.

“An exciting possibility is that these bodies are kept in such an evenly-spaced orbital pattern because of the gravitational influence of a nearby planet. Without this influence, friction and collisions would cause the structures to disperse, losing the precise regularity that is observed. A precedent for this ‘shepherding’ is the way the gravitational pull of moons around Neptune and Saturn help to create stable ring structures orbiting these planets.”

More evidence is needed to confirm the presence of the planet. However, if this hypothesis turns out to be true, the planet’s position relative to its star would be perfect to theoretically allow liquid water – a crucial pre-requisite of life – to exist on its surface. Moreover, it could suggest that more planets like this probably exist around other white dwarves in our galaxy and beyond. “Usually in astronomy, if we find one, it usually means that it’s common,” said Prof Farihi.

A comprehensive description of the white dwarf and the potentially life-supporting planet orbiting it can be found in the journal Monthly Notices of the Royal Astronomic Society. 

Image Credit: ESA/Hubble, M. Kornmesser

By Andrei Ionescu, Staff Writer

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