The study, published in The Astronomical Journal, confirms the existence of G 9–40b. The researchers used the Habitable-zone Planet Finder (HPF) in Texas to confirm the planet’s presence, which was first spotted in 2019 by the Kepler spacecraft.
“G 9–40b is amongst the top twenty closest transiting planets known, which makes this discovery really exciting. Further, due to its large transit depth, G 9–40b is an excellent candidate exoplanet to study its atmospheric composition with future space telescopes,” said the study’s lead author, Guðmundur Stefánsson, in a statement.
A light-year, which measures distance in space, equals 6 trillion miles.
“The spectroscopic observations from HPF allowed us to place an upper bound of 12 Earth masses on the mass of the planet,” said Caleb Cañas, one of the study’s co-authors, added in the statement. “This demonstrates that a planet is causing the dips in light from the host star, rather than another astrophysical object such as a background star. We hope to obtain more observations with HPF to precisely measure its mass, which will allow us to constrain its bulk composition and differentiate between a predominantly rocky or gas-rich composition.”
It’s believed that G 9–40b is “about twice the size of the Earth, but likely closer in size to Neptune.” It also orbits its star, G 9-40, once every 5 days and 17 hours.
The closest confirmed exoplanet to Earth is Proxima Centauri b, which is 4.2 light-years from Earth. In January, researchers discovered the presence of a possible second exoplanet, a “Super-Earth,” also orbiting Proxima Centauri.
G 9-40 is an M dwarf star and is approximately 100 light-years from Earth. It has a surface temperature of approximately 5,600 degrees Fahrenheit, according to The Next Web. For comparison purposes, the Sun has a surface temperature of 10,000 degrees Fahrenheit.
More than 4,000 exoplanets have been discovered by NASA in total, approximately 50 of which were believed to potentially habitable as of September 2018. They have the right size and the right orbit of their star to support surface water and, at least theoretically, to support life.