Two new gaseous planets found by citizen scientists

 Two new gaseous planets have been found orbiting a sun-like star 352 light-years from Earth -- and citizen scientists helped discover them while collaborating with astronomers.

The two exoplanets, which are planets that orbit stars outside of our solar system, are called planet b and planet c. They orbit a star known as HD 152843, which has a similar mass to our sun but is 1.5 times bigger and brighter.

Their discovery was published earlier this month in the journal Monthly Notices of the Royal Astronomical Society.

Planet b is similar in size to Neptune and about 3.4 times larger than Earth. It completes one orbit around the star every 12 Earth days. The outer planet, planet c, is 5.8 times bigger than our planet, which makes it a sub-Saturn. It has an orbit between 19 and 35 Earth days.

For comparison, if both planets were located in our solar system, they would closely orbit the sun.

Citizen scientists were able to help discover these planets by participating in Planet Hunters TESS. This NASA-funded project, available on the Zooniverse website, includes more than 29,000 people around the globe. It allows people to help search for exoplanets using data from NASA's Transiting Exoplanet Survey Satellite, or TESS mission.

The planet-hunting satellite launched in April 2018 and so far, the mission team has identified more than 100 exoplanets and discovered over 2,600 planet candidates that need to be confirmed.

Volunteer citizen scientists use publicly available TESS data to search through graphs that showcase the brightness of stars that the satellite has observed, called light curves. If any of these stars show a dip in brightness, it could suggest that a planet has passed in front of the star during orbit, which is called a transit.

If multiple people submit the same light curves, an algorithm collects them for researchers to analyze. This way, they have exoplanet candidates they can follow up on. It helps to have human eyes on these light curves because computers aren't always able to correctly identify potential planets because it's easy to mistake other phenomena for planets.