Almost 80 exoplanet candidates identified in record time

Search considered successful “dress rehearsal” for exoplanet hunter TESS.

NASA’s Kepler Space Telescope orbits the Sun in concert with the Earth, slowly drifting away from Earth. Image: NASA Kepler Mission/Dana Berry
NASA’s Kepler Space Telescope orbits the Sun in concert with the Earth, slowly drifting away from Earth. Image: NASA Kepler Mission/Dana Berry

Analyzing data from K2, the follow-up mission to NASA’s Kepler Space Telescope, scientists from MIT and elsewhere have found a trove of conceivable exoplanets in the midst of somewhere in the range of 50,000 stars. They discovered nearly 80 new planetary candidates, including a particular standout: a likely planet that orbits the star HD 73344, which would be the brightest planet host ever discovered by the K2 mission.

The planet seems to revolve HD 73344 every 15 days, and in view of the measure of light that it obstructs each time it goes before its star. Researchers evaluate that the planet is around 2.5 times the extent of the Earth and 10 times as huge. It is likewise likely unimaginably hot, with a temperature someplace in the range of 1,200 to 1,300 degrees Celsius, or around 2,000 degrees Fahrenheit — about the temperature of lava from an emitting well of lava.

The planet lies at a moderately close separation of 35 parsecs, or around 114 light along years from Earth. Given its proximity and the way that it orbits a bright star, researchers believe the planet is a perfect contender for follow-up concentrates to decide its barometrical structure and different attributes.

NASA’s Kepler Space Telescope orbits the Sun in concert with the Earth, slowly drifting away from Earth.  Image: NASA Kepler Mission/Dana Berry

The new examination is likewise imperative for the speed with which it was performed. The findings allowed scientists to utilize existing devices created at MIT to quickly seek through diagrams of light force called “lightcurves” from every one of the 50,000 stars that K2 checked in its two late watching efforts. They immediately distinguished the planetary candidates and released the data to the astronomy network a long time after the K2 mission made the spacecraft’s crude information accessible.

Ian Crossfield, an assistant professor of physics at MIT said, “We think it would probably be more like a smaller, hotter version of Uranus or Neptune. Such a fast planet-search enables astronomers to follow up with ground-based telescopes much sooner than they otherwise would, giving them a chance to catch a glimpse of planetary candidates before the Earth passes by that particular patch of sky on its way around the sun.”

“Such speed will also be a necessity when scientists start receiving data from NASA’s Transiting Exoplanet Survey Satellite, TESS, which is designed to monitor nearby stars in 30-day swaths and will ultimately cover nearly the entire sky.”

“When the TESS data come down, there’ll be a few months before all of the stars that TESS looked at for that month ‘set’ for the year”. If we get candidates out quickly to the community, everyone can start immediately observing systems discovered by TESS, and do a lot of great planetary science. So this [analysis] was really a dress rehearsal for TESS.”

The team analyzed data from K2’s 16th and 17th observing campaigns, known as C16 and C17. During each campaign, K2 observes one patch of the sky for 80 days. The telescope is on an orbit that trails the Earth as it travels around the sun. For most other campaigns, K2 has been in a “rear-facing” orientation, in which the telescope observes those stars that are essentially in its rear-view mirror.

Since the telescope travels behind the Earth, those stars that it observes are typically not observable by scientists until the planet circles back around the sun to that particular patch of sky, nearly a year later. Thus, for rear-facing campaigns, there has been little motivation to analyze K2 data quickly.

Amid C16, K2 watched 20,647 stars more than 80 days, between Dec. 7, 2017, and Feb. 25, 2018. On Feb. 28, the mission released the information, as pixel-level pictures, to the space astronomy network. Yu and Crossfield promptly started to filter through the information, utilizing calculations created at MIT to winnow down the field from 20,000-a few stars to 1,000 stars of intrigue.

Scientists then looking through these 1,000 stars by eye for signs of transits, or periodic dips in starlight that could signal a passing planet. In the end, they discovered 30 “highest-quality” planet candidates, whose periodic signatures are especially likely to be caused by transiting planets.

They also identified a similar number of planet candidates in the recent C17 analysis. In addition to these planetary candidates, the group also picked out hundreds of periodic signals that could be signatures of astrophysical phenomena, such as pulsating or rotating stars, and at least one supernova in another galaxy.

Crossfield says, “While the nature of a star doesn’t typically change over the course of a year. You want to observe [candidates] again relatively soon so you don’t lose the transit altogether. You might be able to say, ‘I know there’s a planet around that star, but I’m no longer at all certain when the transits will happen.’ That’s another motivation for following these things up more quickly.”

“We found one of the most exciting planets that K2 has found in its entire mission, and we did it more rapidly than any effort has done before. This is showing the path forward for how the TESS mission is going to do the same thing in spades, all over the entire sky, for the next several years.”

In a paper that appears online today in The Astronomical Journal.