Since its first light in 2009, the Kepler Space Telescope has been scanning the cosmos in search of habitable worlds beyond our Solar System. During its routine observations, the telescope observed something very unusual. Nestled between the constellations Cygnus and Lyra, sits a strange and intriguing star.
Kepler is designed to observe stars and look for tiny dips in their brightness. These dips, especially if they repeat, can be a sign the star has one or more planets orbiting it. By measuring the timing and the size of the dips, scientists can learn a great deal about the transiting planet. The data is then processed automatically by computers with algorithms designed to look for repeating patterns – a sign that something is orbiting the star.
Kepler focused on this one region for four years, observing as many as 150,000 stars simultaneously. Due to the massive amounts of data collected, Kepler scientists rely on “citizen scientists” through a website called Planet Hunters to help them scour the data for anything unusual. In 2011, one star in particular was flagged as unusual.
Kepler observed the star KIC 8462852 for four years starting in 2009. Typically, orbiting planets only dim the light of their host star for a period of a few hours to a few days depending on their orbit. A group of citizen scientists noticed that this star appeared to have two small dips in 2009, followed by a large dip lasting almost a week in 2011, and finally a series of multiple dips significantly dimming the star’s light in 2013.
Tabetha Boyajian, a postdoc at Yale, told The Atlantic: “We’d never seen anything like this star. It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.”
The pattern of dips indicates that the star is orbited by a large, irregular-shaped mass. If it were orbiting a young star, this mass might be a protoplanetary disc, but KIC 8462852 is not a young star. We would also expect to see the presence of dust emitting infrared light, which hasn’t been observed. So what is this orbiting mass? Scientists predict that whatever it is, it had to have formed recently as it would have been pulled in by the star’s gravity and consumed.
Boyajian recently published a paper offering several possible explanations for the bizarre transits. The leading theory is that a family of exocomets passed too close to the star, and were shredded into pieces by the star’s massive gravity. The remaining dust and debris could be left to orbit the star.
But researchers from UC Berkeley’s SETI Institute think it could be something else entirely: They think this could be a sign of alien technology. Boyajian is working with SETI and Jason Wright, an astronomer from Penn State University, to develop a proposal to observe the star with NRAO’s Green Bank Telescope to search for radio waves. If they detect anything intriguing, they then have plans to use the Very Large Array (VLA) in New Mexico to listen for what could be the sounds of alien technology.
The first observations are estimated to take place in January, with a potential follow-up planned for next fall. Of course, if they stumble upon something incredible, the researchers could expect to follow-up with the VLA straight away. Kepler also plans to observe KIC 8462852 in May 2017, when the mass is expected to transit the star again.