Far away, in a star system known as KIC 4862625, there exists a planet illuminated by four different suns. This may seem like something out of Star Wars where Luke Skywalker’s home planet Tatooine was graced with two setting suns, but the recently discovered planet with its four suns is real. Welcome to the exotic world of exoplanets circling stars beyond our solar system.
What is even more remarkable is how this newfound planet was discovered – by two amateur astronomers, Dr. Robert Gagliano, an oncologist from Arizona, and Kian Jek, a semi-retired computer executive from California, collaborating over the internet. Both are volunteers in an online project called Planet Hunters (www.planethunters.org), established in 2010, in which participants, using their home computers, search for exoplanets. They do this by analyzing data from NASA’s Kepler Space Telescope, launched in 2009 to search for Earth-like planets orbiting other stars. The volunteers, who need have no expertise in astronomy, examine graphs of light from individual stars, looking for the dip in brightness that indicates a planet moving in front of, or transiting, a star.
While analyzing the binary, or two-star, system KIC 4862625, Gagliano noticed the signal of a possible transiting planet. He then noted that the planet appeared to transit twice, with an orbit of 137 days. Gagliano posted his observations on the Planet Hunters’ online forum where it was noticed by Kian Jek who, on further study, found a third transit that also corresponded with a 137 day orbit.
Led by Megan Schwamb of Yale University, the team of professional astronomers that oversees Planet Hunters then investigated further, using various instruments, including the Keck telescopes on Mauna Kea in Hawaii. They concluded that what Gagliano and Jek had found was a gaseous planet 5,000 light years away, with a radius about 6.2 times larger than Earth’s, and with four, rather than two suns. The planet, about the size of Neptune, orbits one binary star system, a pair of stars that orbit each other, and this system is, in turn, orbited by a second pair of stars farther out.
What is not well understood is why the planet isn’t pulled apart by the gravity exerted on it by the four stars. According to Dr. Chris Lintott of Oxford University, the few planets known to orbit double stars are all orbiting close to their stars. It would therefore seem likely that the gravity exerted by the nearby stars is strong enough to allow the planet to maintain a stable orbit.
The newly discovered planet, named PH1, is the first confirmed exoplanet discovered by the Planet Hunters collaboration. It is also the first planet known to have four suns. Binary star systems are quite common. However, only six exoplanets have been found to orbit such binaries, and none of these were known to have another pair of stars orbiting them – until now.
By virtue of thinking differently, humans can sometimes spot something a computer has missed, so given the large number of participants in the Planet Hunters project (over 170,000 volunteers so far), perhaps more planets with multiple suns or other strange features will soon be discovered.
Join the Springfield Stars Club on Tuesday, November 27th at 7:30pm at the Springfield Science Museum for a presentation by Jack Megas and Tim Connolly on “Mysteries of the Aurora.” Refreshments will be served, and the public is welcome free of charge. Megas and Connolly will explain the night sky light display known as the northern lights or aurora borealis in the northern hemisphere and the aurora astralis in the southern hemisphere. Their talk will be accompanied by striking photos and video footage of auroras around the world. Jack Megas is an astronomy educator at the Springfield Science Museum’s Seymour Planetarium, and a retired laboratory hematologist at Bay State Medical Center. He is a past president of both the Springfield Stars Club and the Naturalist Club. Tim Connolly, an amateur astronomer, is employed by Baystate Medical Center’s Pathology Department, performing diagnostic electron microscopy. He has a BS degree in biology, chemistry, physics and astronomy. Connolly is secretary of the Amherst Area Amateur Astronomers Association.
Copyright © Amanda Jermyn