MessageToEagle.com - Two years ago, Hubble Space Telescope observed a
planet being eaten by its parent star. The doomed planet may only have another 10 million years left before it is completely devoured.
Will Earth also be consumed by our Sun?
The idea of stars "swallowing planets" is not new in the literature
and astronomical observations of this process continue.
Now, an international team of astronomers has discovered the first evidence of a planet's destruction by its aging star.
The evidence indicates that the missing planet was devoured as the star began expanding into a "red giant" - the stellar
equivalent of advanced age.
"A similar fate may await the inner planets in our solar system, when the Sun becomes a red giant and expands all the way
out to Earth's orbit some five-billion years from now," said Alex Wolszczan, an Evan Pugh Professor of Astronomy and
Astrophysics at Penn State University, who is one of the members of the research team.
Wolszczan also is the discoverer of the first planet ever found outside our solar system.
The astronomers also discovered a massive planet in a surprisingly elliptical orbit around the same red-giant star,
named BD+48 740, which is older than the Sun with a radius about eleven times bigger.
The evidence of the missing planet's destruction was discovered, while astronomers were using the Hobby-Eberly Telescope to
study the ageing star and to search for planets around it.
The evidence includes the star's peculiar chemical composition, plus the highly unusual elliptical orbit of its surviving planet.
"Our detailed spectroscopic analysis reveals that this red-giant star, BD+48 740, contains an abnormally high amount
of lithium, a rare element created primarily during the Big Bang 14 billion years ago," Adamow said.
An artist's depiction of an early stage in the destruction of a hot Jupiter by its star. Credit: NASA/GSFC/Frank Reddy
Lithium is easily destroyed in stars, which is why its abnormally high abundance in this older star is so unusual.
"Theorists have identified only a few, very specific circumstances, other than the Big Bang, under which lithium can be
created in stars," Wolszczan noted.
"In the case of BD+48 740, it is probable that the lithium production was triggered by a mass the size of a planet
that spiraled into the star and heated it up while the star was digesting it," he suggested.
Star eating one of its close-in planets in the Constellation Auriga, 600 light years from Earth. Credits: NASA/ESA/G. BAcon STScl
The second piece of evidence discovered by the astronomers is the highly elliptical orbit of the star's newly discovered
massive planet, which is at least 1.6 times as massive as Jupiter.
"We discovered that this planet revolves around the star in an orbit that is only slightly wider than that of Mars at its
narrowest point, but is much more extended at its farthest point," Niedzielski said.
"Such orbits are uncommon in planetary systems around evolved stars and, in fact, the BD+48 740 planet's orbit is the
most elliptical one detected so far."
Because gravitational interactions between planets are responsible for such peculiar orbits, the astronomers suspect
that the dive of the missing planet toward the star before it became a giant could have given the surviving massive
planet a burst of energy, throwing it into an eccentric orbit like a boomerang.
Beautiful Night Sky Timelapse
Takes You On A Journey To Astronomer's Paradise
There are not many locations left on this planet where you can still experience a dark sky like this.
Walking on the desert near Paranal between the scattered stones and boulders on the pale red dust feels like being on Mars but under the Earth sky.
It is an amazing experience to be under an ideal night sky, a pure natural beauty unspoiled by urban lights.