Planet-Eating Death Star Discovered By Astronomers

Posted: Dec 16 2016, 11:24pm CST | by , Updated: Dec 16 2016, 11:30pm CST, in News | Latest Science News

 

Planet-Eating Death Star Discovered by Astronomers
HIP68468, a twin star to the sun about 300 light-years away, may have swallowed one or more of its planets. Credit:Gabi Perez / Instituto de Astrofísica de Canarias
 

The discovery holds clues to the evolution of plantery systems

Planets form around stars and orbit them in a precise manner. However, a team of international researchers have found the evidence of a star that has eaten way some of its planets.

The star, HIP68468, is located 300 light years away from the Earth and is comparable to our own Sun in terms of temperature, size and mass.

To date no star with exact match as that of sun has been discovered, however, there are some that closely resemble our sun. These stars are called solar twins and HIP68468 is among those several stars that fall in this category.

The discovery of planet-destroying Death Star indicates that some of the planetary systems actually had turbulent pasts and they gradually became stable over time. This system could also hold clues to the formation and evolution of planetary systems.

“It doesn’t mean that the sun will ‘eat’ the Earth any time soon,” said co-author Jacob Bean, assistant professor of astronomy and astrophysics at University of Chicago. “But our discovery provides an indication that violent histories may be common for planetary systems, including our own.”

Thousands of exoplanets have been discovered in the past two decades but very few of them orbit around a star similar to our Sun. This makes HIP68468 an ideal candidate to investigate the relation between stars and their planets. 

In 2015, the first exoplanet for the star HIP68468 was discovered while two more exoplanets dubbed “super Neptune” and “super Earth” have been detected more recently. The two new planets revolve so close to their host star that one of them takes just three days to complete an orbit. Observations suggest that these planets were not originally formed there. They probably brought inward from the outer parts of the planetary system and were also accompanied by other planets. The other planets could have either been ingested by the star or possibly ejected from the system.

To arrive at the conclusion, researchers used the observations from 3.6-meter telescope mounted  in Chile and found that the stars contains four times more lithium than would be expected for a star that is 6 billion years old.

The interiors of hot stars like HIP68468 consume lithium over time whereas planets contain them as they do not have high enough temperature to destroy the element. As a result, when a star engulfs a planet, the lithium that the planet has inside it becomes evident. 

The lithium and the potentially consumed rocky planet material in the atmosphere of HIP68468 is equivalent to the mass of six Earths.

“It can be very hard to know the history of a particular star, but once in a while we get lucky and find stars with chemical compositions that likely came from in-falling planets,” said Debra Fischer, a professor of astronomy at Yale University who was not involved in the research. “That’s the case with HD68468. The chemical remains of one or more planets are smeared in its atmosphere.”

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Hira Bashir covers daily affairs around the world.

 

 

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