A team of astronomers, led by Andrew Vanderburg of the Harvard–Smithsonian Center for Astrophysics (CfA), has recently detected five new exoplanets circling a bright star designated HIP 41378, which lies some 380 light-years away. The newly found alien worlds are larger than our planet, with sizes ranging from about 2.5 times the size of Earth to the size of Jupiter. The findings were presented in a paper published June 27 on the arXiv pre-print server.
The planetary system was spotted by NASA’s prolonged Kepler mission, known as K2. HIP 41378 was observed by K2 for a period of about 75 days between April 27, 2015, and July 10, 2015. This new data, complemented by follow-up spectroscopic observations, allowed the scientists to detect transiting events and distinguish five planetary candidates. However, the team admits that it wasn’t an easy task to unveil the new exoplanets.
“Finding these planets was challenging in several ways. One challenge is in processing K2 data so that it is even possible to detect planets. Ever since the mechanical failure in 2013 that ended the original Kepler mission, K2 has been taking data while the telescope drifts back and forth, which causes problems with the data,” Vanderburg told Astrowatch.net.
However, he added that his team found a solution to the problem of the telescope drifting, allowing them to receive much ‘cleaner’ data. Overcoming the spacecraft’s instability issues, Martti Holst Kristiansen from the Technical University of Denmark, a member of the team, identified the five transits in diagrams, when closely inspecting the K2 data regarding HIP 41378.
“Once Andrew’s corrected data was released we revisited our multi-planet candidate and were finally able to distinguish the noise from genuine planets. The discovery of this remarkable system definitely had some challenges implicated,” Kristiansen told SpaceFlight Insider.
According to the research paper, the newly detected planetary system includes two sub-Neptune-sized planets, designated HIP 41378 b and HIP 41378 c, having a radius of about 2.9 and 2.56 Earth radii, respectively. HIP 41378 b has the shortest orbital period of all the currently known planets in the system, circling its host star every 15.6 days. The other sub-Neptune exoplanet needs 16 days more to orbit HIP 41378.
HIP 41378 d is a Neptune-sized planet, about four times larger than the Earth. Its orbital period is 157 days. The system also hosts a sub-Saturn-sized exoplanet, named HIP 41378 e, which has a radius of approximately 5.5 Earth radii and orbits its parent star every 131 days.
However, the planet that intrigues the researchers the most is HIP 41378 f. With a radius ten times greater than Earth’s, it is a Jupiter-sized planet that takes almost a year to orbit the star.
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