The Habitable-Zone Planet Finder located in Texas, USA, helped validate G 9-40b. It is a sub-Neptune planet orbiting around star G 9-40, and Kepler Space Telescope discovered it. The term sub-Neptune can refer to a world with a smaller radius than Neptune, even though it may have a more substantial mass or to a planet with a lower mass than Neptune, also though it may have a larger radius.
In the Astronomical Journal, a study was published: “A Sub-Neptune-sized Planet Transiting the M2.5 Dwarf G 9-40: Validation with the Habitable-zone Planet Finder”.
The planet is 2 Earth radii and the star it orbits a low mass M-dwarf star. G 9-40b is one of the most favorable sub-Neptune-sized planets orbiting an M-dwarf for transmission with the James Webb Space Telescope, so astronomers are excited about the future spectroscopy.
It is located 100 light-years from Earth. It completes its orbit once every five days and 17 hours at a distance of 5,760,000 km. That is 25 times closer than the distance between the Earth and the Sun.
The first validation for the Habitable-Zone Planet Finder’s success is the exoplanet G 9-40b
The star it orbits is relatively cool. Compared to the temperature of the surface of the Sun, which is roughly 5,500 C, the M-dwarf has a surface temperature of just over 3,100 degrees Celsius.
Until now, there was still doubt about G 9-40b identity. The astronomers weren’t sure if it is a background star or an exoplanet. To establish that it is a star, lots of joined forces were needed beside The Habitable-Zone Planet Finder.
The HPF is an astronomical spectrograph installed on the 10-meter Hobby-Eberly Telescope at the McDonald Observatory in Texas, USA. The telescope has an extended K2 mission, and G 9-40b is the second-close transiting planet found with it. G 0-40b is in one of the 20 closest transiting planetary systems known.
Findings of G 9–40b were confirmed by astronomers using the 3.5-meter telescope at Apache Point Observatory and the three-meter Shane Telescope at Lick Observatory.