Exoplanet being killed by its own host star

Baby exoplanet being killed by its own host star

A fast-moving exoplanet that takes merely 11 hours to orbit around its sun is in danger as its host star is quickly stripping its gaseous atmosphere. The exoplanet, dubbed PTFO8-8695b, is very close to his sun, which is allowing its host star’s gravity to strip its outer layers away.

Astronomer Christopher Johns-Krull of Rice University, said, “A handful of known planets are in similarly small orbits, but because this star is only 2 million years old this is one of the most extreme examples … the weight of the evidence suggests this is one of the youngest planets yet observed.”

The exoplanet’s age of two million years may seem very huge for a human, but it is very short for a planet. Earth is nearly 2,300 times older than this exoplanet.

Astronomers discovered PTFO8-8695b many years ago, when they noticed that the brightness of its host star was occasionally dimmed.

While the exoplanet PTFO8-8695b is very young in age, it is roughly twice the size of Jupiter -- the biggest planet in our solar system. Located nearly 1,100 light years away from our planet in the constellation Orion, it has been classified as “hot Jupiter,” a class of gaseous planets that are very close to their host stars.

According to a report in IB Times by Avaneesh Pandey, "Orbiting a young star nearly 1,100 light-years from Earth lies what may be one of the youngest alien planets ever detected. However, this young exoplanet candidate, which scientists believe is probably a “hot Jupiter” — a term used to describe large planets locked in an extremely close orbit around their parent stars — is doomed from the start. According to a paper that has been submitted for publication in the Astrophysical Journal, this planet, which orbits its parent star every 11 hours, is locked in a slow “death spiral” that will eventually tear it to shreds."

“We don’t yet have absolute proof this is a planet because we don’t yet have a firm measure of the planet’s mass, but our observations go a long way toward verifying this really is a planet,” he added. “We compared our evidence against every other scenario we could imagine, and the weight of the evidence suggests this is one of the youngest planets yet observed.”

“We don’t know the ultimate fate of this planet,” Johns-Krull said in the statement. “It likely formed farther away from the star and has migrated in to a point where it’s being destroyed. We know there are close-orbiting planets around middle-aged stars that are presumably in stable orbits. What we don’t know is how quickly this young planet is going to lose its mass and whether it will lose too much to survive.”

A report published in the CBS News said, "There may be a previously undiscovered planet out there that's getting a serious sunburn. Astronomers on the hunt for the galaxy's youngest planets might have found a newly formed so-called "hot Jupiter," whose outer layers are bring relentlessly ripped off by its nearby star. More damage is done with each orbit, which take just 11 hours apiece. The research comes out of Rice University and will be published in The Astrophysical Journal. It was made available online this week."

"In 2012, there was no solid evidence for planets around 2-million-year-old stars," Prato added. "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."

"PTFO 8-8695 b was first identified several years ago, when another team of researchers began noticing regular dips in the brightness of the star it orbits. This suggested that a planet was crossing in front of the star, briefly blocking some of its light from Earth's view. But the star was young — just about 2 million to 3 million years old — and young stars are often covered in sun spots that make then gutter and flare unpredictably. So there was some skepticism that a planet had really been found," according to a news report published by Washington Post.

Using spectroscopic analysis, which divides light up into its component parts, they identified two separate sources of a type of light emitted by highly energized hydrogen atoms, called H alpha. One set of H alpha emissions was clearly coming from the star, since it carried signatures of the type of magnetic activity that happens on stars. But the other source seemed to move back and forth across the star — at exactly the pace you would expect to see from a planet like PTFO 8-8695 b, based on previous observations of its transit.