Relatively Young “Hot Jupiter” Being Devoured by Host Star

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Credit: A. Passwaters/Rice University

Our planet hunting ambitions have paid off in recent years with over thousand confirmed planets. In the database are quite a few unique planet groups – one of them in particular is astonishing where the host star is found to be killing the planet.

One such planet “PTFO8-8695 b” was recently discovered orbiting its host star PTFO8-8695 every 11 hours and this indicates that the planet is in close proximity to the star. According to a new study published in the Astrophysical Journal, researchers have said that the planet is like a ‘hot Jupiter’ and that the closeness of the planet to its host star is having a devastating effect on the former as its outer layers are being stripped off slowly.

We have come across such planet-star systems previously, but the interesting bit about this one is that the star is only 2 million years old – relatively very young in cosmic terms. Christopher Johns-Krull, lead author of the study, says that they are still researching the planet to obtain 100 per cent proof that “PTFO8-8695 b’ is in fact a planet, but their study so far has led them to conclude with a certain degree of certainty that the object is indeed a planet.

The planet “PTFO8-8695 b” is orbiting the star about 1,100 light years from Earth in the constellation of Orion and findings indicate that is at most twice the mass of Jupiter. Researchers have said that while the planet’s outer layers are currently being stripped off, they are not aware of the fate of the planet. Further, chances are that the planet may have formed farther away from the star, but it may have migrated in to a point where it’s being destroyed.

PTFO8-8695 b was identified as a candidate planet in 2012 by the Palomar Transit Factory’s Orion survey. The planet’s orbit sometimes causes it to pass between its star and our line of sight from Earth, therefore astronomers can use a technique known as the transit method to determine both the presence and approximate radius of the planet based on how much the star dims when the planet “transits,” or passes in front of the star.

“In 2012, there was no solid evidence for planets around 2 million-year-old stars,” said Lowell Observatory astronomer Lisa Prato. “Light curves and variations of this star presented an intriguing technique to confirm or refute such a planet. The other thing that was very intriguing about it was that the orbital period was only 11 hours. That meant we wouldn’t have to come back night after night after night, year after year after year. We could potentially see something happen in one night. So that’s what we did. We just sat on the star for a whole night.”

A spectroscopic analysis of the light coming from the star revealed excess emission in the H-alpha spectral line, a type of light emitted from highly energized hydrogen atoms. The team found that the H-alpha light is emitted in two components, one that matches the very small motion of the star and another than seems to orbit it.

The team observed the star PTFO8-8695 dozens of times from the University of Texas at Austin’s McDonald Observatory near Fort Davis, Texas, and the Kitt Peak National Observatory 4-meter telescope in southern Arizona.

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