October 25, 2013
Astronomers Discover Seventh Planet Orbiting Nearby Star System
Lee Rannals for redOrbit.com - Your Universe Online
Astronomers have discovered a seventh planet orbiting a dwarf star, known as KIC 11442793, making it the first Kepler planetary system with this many alien worlds.
The star is about 2,500 light years from Earth and its planetary system could be a record holder. All seven planets in the system orbit much closer to their host star, meaning the system is very crowded when compared to even our own Solar System.
Scientists say that the planetary system, known as KOI-351, bears some resemblance to our planetary neighborhood. The system contains five inner planets ranging from Earth to mini-Neptune radii, and the outer planets are gas planets. However, all of these planets have an orbit smaller than the distance between the Earth and the sun, which is about one astronomical unit (AU), or 92,955,807.3 miles.
The Astronomers also said they discovered 13 other transiting planet candidates in the Kepler field from the Planet Hunters citizen science program. They said that none of the candidates overlap with Kepler Objects of Interests, and five of them were missed by the Kepler Transit Planet Search (TPS) algorithm.
Planet Hunters is a Yale-led program that asks for the public’s help to review astronomical data from the NASA Kepler spacecraft. Volunteers are asked to try and spot faint dips in light that are caused by the planet passing in front of its parent stars. Last year, astronomers participating in the program discovered a planet orbiting twin suns.
Joey Schmitt, lead author of the paper being submitted to the Astronomical Journal, said that while they cannot confirm the candidates in KOI-351, gravitational interactions between the planet candidates overwhelmingly point to their planetary nature.
“It is also known that false positives in multiple candidate systems are extremely rare. All of this together makes KOI-351 the strongest case for the first seven planet system known (apart from our own Solar System, of course!),” Schmitt said.
The newly discovered planet is the fifth farthest from its parent star and has an orbiting period of nearly 125 days. The exoplanet has a radius 2.8 times that of the Earth, meaning the planetary system is known to contain two “Earth-sized” planets, three “super-Earths” and two larger bodies.
Schmitt said that of the 14 planets identified, eight reside in their host star’s habitable zone, but none of them approach Earth or super-Earth size.
“We will include the names of the first identifiers in the final version of the paper. The Planet Hunters team continues on other exciting papers currently in the works. Thanks to all the Planet Hunters who have participated in this great project. We could not have done it without your help,” Schmitt said.