For the first time in history, a crowdsourced team of amateur citizen scientists has discovered a multi-planetary system. And that is how the five exoplanets of K2-138 were found.
An artist's depiction of K2-138. After a wheel on the spacecraft malfunctioned in 2013, Kepler was reconfigured in 2014 so the telescope continued collecting data from certain parts of the sky for limited periods, and the phase since has been called K2.
They also found that planets orbiting the same star tend to have a regular orbital spacing. The most distant planet, K2-138f, is one-tenth the distance that Earth is to the Sun. Using the depth of the transit curve and the periodicity with which it appears, they made estimates for how large the potential planet is and how close it orbits to its star. Due to their close proximity to the star, these planets are nearly certainly uninhabitable.
K2-138 is no TRAPPIST-1 - a star system containing seven Earth-sized planets, including three located within the habitable zone - but it's a cool discovery nonetheless.
Citizen scientists have discovered five tightly packed planets outside our solar system, almost 620 light years from Earth, using data from NASA's Kepler Space Telescope. Kepler works by measuring the brightness of stars. No professional astronomer had yet looked through this dataset, called C12. Known as the C12 dataset, this represents a disgusting amount of data for scientists to sift through.
Another batch of 2017 Kepler data was recently uploaded to Exoplanet Explorers for citizen scientists to peer through. But it was a feature on the ABC Australia television series Stargazing Live that ultimately yielded the most new data from citizens. Audience members were encouraged to participate by parsing through the data in search of candidate exoplanets.
Users could then sift through actual light curves from the K2 mission and click "yes" or "no", depending on whether they thought the curve looked like a transit. In the first 48 hours after the project was introduced, Exoplanet Explorers received over 2 million classifications from more than 10,000 users. Christiansen, along with UC Santa Cruz astronomer Ian Crossfield and NASA astronomer Geert Barentsen, examined the incoming data, resulting in many new candidates, including 44 Jupiter-sized planets, 72 Neptune-sized, 44 Earth-sized and 53 so-called super-Earths, which are larger than Earth but smaller than Neptune. "But those can take a while to validate, to make sure that it really is a real planet and not a false alarm".
To gain a better understanding of this hypothesis, Weiss and her term are taking a closer look at Jupiter-like planets in multi-planet systems.
And that's exactly what they did - detecting a star with four planets orbiting around it. Three of the four planets had 100 percent "yes" votes from over 10 people, and the remaining one had 92 percent "yes" votes.
The planets also appear to orbit their star in concentric circles, forming a tightly packed planetary system, unlike our own elliptical, far-flung solar system.
Citizen scientists have struck again.