Scientists Discover a Pair of ‘Cataclysmic’ Stars That Orbit Each Other in Less Than an Hour

Scientists have discovered a pair of stars locked in an incredibly close orbit that spin once every 51 minutes – and according to the results of a new study, they will only speed up.

The universe is a chaotic place when it comes to orbital mechanics. Our solar system, seen in relation to the rest of the cosmos, is a little vanilla. We have our central star – the Sun – which orbits eight major planets which are in turn escorted across the heavens by a plethora of moons and rings of different levels of awesome.

However, astronomers have found that about half of the star systems in our Milky Way are actually made up of multiple stars gravitationally bound together. The Alpha Centauri system – which is the closest neighboring stellar population to our Sun – is actually a collection of three stars that orbit about 4 light-years away. From land.

Stars are among the most massive and dynamic bodies in the universe, and so, naturally, binary star systems can have some pretty extreme characteristics.

In a new study, a team of scientists has discovered a rare pair of stars known as the “Cataclysmic Variable”, which complete a full orbit of each other in less than an hour.

A cataclysmic variable is a system in which a super dense white dwarf star orbits another stellar body similar to our Sun. White dwarfs are planet-sized stellar cores that have exhausted their nuclear fuel and shed their outer layers.

In a cataclysmic variable system, a super-dense white dwarf orbits so close to a companion star that its gravity allows it to steal hydrogen from the atmosphere of the larger stellar body.

Artist's impression of a cataclysmic binary system (Credit: M.Weiss/Center for Astrophysics | Harvard & Smithsonian)

Artist’s impression of a cataclysmic binary system (Credit: M.Weiss/Center for Astrophysics | Harvard & Smithsonian)

The newly discovered star system, which has been imaginatively named ZTF J1813+4251, was first discovered by researchers investigating the Zwicky Transient Facility (ZTF). The catalog contains high-resolution images of over a billion stars and tracks changes in their apparent brightness over time.

Kevin Burdge, one of the authors of the new study published in the scientific journal Nature, used a computer algorithm to sort through the ZTF catalog to find flashes in the light signature of distant bodies that would suggest the presence of two stars in close orbit.

This search reported about 1 million stars from the billion star database. ZTF J1813+4251 stood out among the candidates, with flashes of light from the remote source suggesting it was a binary system.

Follow-up observations from the mighty Gran Telescopio Canarias in Spain and the WM Keck Observatory in Hawaii have made it possible to discern the radii, masses and orbits of the two bizarre stars.

ZTF J1813+4251 was revealed to be likely a cataclysmic variable, consisting of a geriatric star roughly the size of Jupiter with a mass equivalent to 1/10th that of our Sun. This stellar body orbits with an ultra-dense white dwarf, which boasted a mass roughly half that of our Sun, packed into space 1/100th its volume, according to a Press release from Massachusetts Institute of Technology.

Incredibly, these two stellar bodies appear to orbit each other once every 51 minutes, giving them the shortest orbit of any cataclysmic variable discovered to date.

The researchers took the data on ZTF J1813+4251 and used it to simulate the duo’s likely evolutionary path spanning more than a hundred million years into the future. The results suggest that the stars are currently in a transition phase, in which the white dwarf is removing large amounts of hydrogen from the atmosphere of the larger star.

This process will likely continue until only a helium-dominated core remains. Over the next 70 million years, this dense core will pull the pair into an even tighter orbital period of just 18 minutes. The results confirm an earlier study that predicted this behavior from cataclysmic variables.

Be sure to check The scientific page of the IGN for more cosmic goodness.

Anthony Wood is independent Science editor for IGN

Image Credit: Credit: M.Weiss/Center for Astrophysics | Harvard and Smithsonian

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