ScienceDaily: Latest Science News: Lava world baffles astronomers: Planet Kepler-78b 'shouldn't exist'

ScienceDaily: Latest Science News

Breaking science news and articles on global warming, extrasolar planets, stem cells, bird flu, autism, nanotechnology, dinosaurs, evolution -- the latest discoveries in astronomy, anthropology, biology, chemistry, climate and environment, computers, engineering, health and medicine, math, physics, psychology, technology, and more -- from the world's leading universities and research organizations.

Lava world baffles astronomers: Planet Kepler-78b 'shouldn't exist'
http://feeds.sciencedaily.com/~r/sciencedaily/~3/CNvPYxc3ebs/131030142915.htm
Oct 30th 2013, 18:29

Oct. 30, 2013 — Kepler-78b is a planet that shouldn't exist. This scorching lava world circles its star every eight and a half hours at a distance of less than one million miles -- one of the tightest known orbits. According to current theories of planet formation, it couldn't have formed so close to its star, nor could it have moved there.
"This planet is a complete mystery," says astronomer David Latham of the Harvard-Smithsonian Center for Astrophysics (CfA). "We don't know how it formed or how it got to where it is today. What we do know is that it's not going to last forever."
"Kepler-78b is going to end up in the star very soon, astronomically speaking," agrees CfA astronomer Dimitar Sasselov.
Not only is Kepler-78b a mystery world, it is the first known Earth-sized planet with an Earth-like density. Kepler-78b is about 20 percent larger than Earth, with a diameter of 9,200 miles, and weighs almost twice as much. As a result it has a density similar to Earth's, which suggests an Earth-like composition of iron and rock.
The tight orbit of Kepler-78b poses a challenge to theorists. When this planetary system was forming, the young star was larger than it is now. As a result, the current orbit of Kepler-78b would have been inside the swollen star.
"It couldn't have formed in place because you can't form a planet inside a star. It couldn't have formed further out and migrated inward, because it would have migrated all the way into the star. This planet is an enigma," explains Sasselov.
According to Latham, Kepler-78b is a member of a new class of planets recently identified in data from NASA's Kepler spacecraft. These newfound worlds all orbit their stars with periods of less than 12 hours. They're also small, about the size of Earth. Kepler-78b is the first planet in the new class to have its mass measured.
"Kepler-78b is the poster child for this new class of planets," notes Latham.
The team studied Kepler-78b using a newly commissioned, high-precision spectrograph known as HARPS-North, at the Roque de los Muchachos Observatory on La Palma. They coordinated their work with a second, independent team using the HIRES spectrograph at the Keck Observatory. The teams' measurements agreed with each other, increasing their confidence in the result.
Kepler-78b is a doomed world. Gravitational tides will draw it even closer to its star. Eventually it will move so close that the star's gravity will rip the world apart. Theorists predict that Kepler-78b will vanish within three billion years.
Interestingly, our solar system could have held a planet like Kepler-78b. If it had, the planet would have been destroyed long ago leaving no signs for astronomers today.
Kepler-78b orbits a Sun-like G-type star located 400 light-years from Earth in the constellation Cygnus.
This entry passed through the Full-Text RSS service — if this is your content and you're reading it on someone else's site, please read the FAQ at fivefilters.org/content-only/faq.php#publishers. Five Filters recommends: Massacres That Matter - Part 1 - 'Responsibility To Protect' In Egypt, Libya And SyriaMassacres That Matter - Part 2 - The Media Response On Egypt, Libya And SyriaNational demonstration: No attack on Syria - Saturday 31 August, 12 noon, Temple Place, London, UK



You are receiving this email because you subscribed to this feed at https://blogtrottr.com

If you no longer wish to receive these emails, you can unsubscribe here:
https://blogtrottr.com/unsubscribe/cz0/tSbHWJ