An international team of astronomers spearheaded by the French space agency, CNES, have confirmed the existence of a planet named CoRoT-9b. Members of this team included scientists from the UCSB-affiliated Las Cumbres Observatory Global Telescope Network in Goleta.
According to the paper on the finding, which was published in the March 18 issue of the journal Nature, the newly discovered planet is a gas giant similar to Jupiter and orbits a star in the constellation Serpens Cauda, 1500 light-years from Earth.
Evidence of the planet’s existence was first discovered in 2008 by the CNES orbital telescope, CoRoT, after which the planet was named. However, CoRoT-9b’s existence could not be confirmed until recently, when its existence was corroborated by a series of terrestrial observatories around the world, including the LCOGT.
According to Avi Shporer, a UCSB postdoctoral fellow working at LCOGT who contributed to the finding, the planet was discovered because it was transiting, effectively causing miniscule eclipses.
In astronomy, a planet transits when it passes between the star it is orbiting and Earth, causing the star to appear slightly dimmer to terrestrial observers.
Astronomers use this phenomenon to locate planets by searching for stars that periodically become dimmer.
“[We search] for transiting planets by intensively monitoring the light intensity of many stars and looking for those which become slightly dimmer for a few hours, once every few days, or 95 days in the case of CoRoT-9b star,” Shporer said.
This phenomenon can be used to determine a great deal of information about the planet. The size of its orbit, and thus its distance from the star, can be determined by the frequency of its transits, and the size and type of the planets can be determined by measuring exactly how much light it blocks from its host star.
CoRoT-9b is unique because it is much farther from its host star than any planet previously discovered using this method, and therefore is far colder as well. According to Shporer, these properties present a unique opportunity to astronomers who are eager to examine the unique properties the planet’s atmosphere would have as a result of this colder temperature.
“Compared to all other transiting extra solar planets, CoRoT-9b is almost 10 times further away from the parent star,” Shporer said. “This makes CoRoT-9b much colder than them, so we have the first opportunity to study an atmosphere which is relatively cold, or temperate.”
The primary reason CNES requires the assistance of terrestrial observatories to discover extra-solar planets, Shporer said, is because the CoRoT satellite is fallible, sometimes reporting planets that do not exist. LCOGT and the other observatories help by confirming the CoRoT satellite’s findings and weeding out false positives.
“Due to technical reasons, every initial detection made by the CoRoT space telescope must be verified from the ground,” Shporer said. “Many times these ground-based observations actually prove this initial detection was a false alarm. LCOGT is part of this ground-based campaign, participated [in] by many telescopes world-wide.”
In addition to Shporer, Tim Lister, Rachel Street and Marton Hidas from LCOGT contributed to the finding and publication on the new planet.