Newly discovered Earth-size planet TOI 700 e orbits within the habitable zone of its star in this illustration. Its Earth-size sibling, TOI 700 d, can be seen in the distance. Image Credit: NASA/JPL-Caltech/Robert HurtTechnology USA
Our Neighbor Star Has Two Planets Where Life Could Thrive
Only 100 light-years from our solar system, a red dwarf now has a second planet that orbits in its habitable zone, a discovery that helps us understand more thoroughly red dwarfs which are abundant in our galaxy.
“Planet [TOI 700] e is about 10% smaller than planet [TOI 700] d, so the system also shows how additional observations made by NASA’s Transiting Exoplanet Survey Satellite help us find smaller and smaller worlds, which makes the TOI 700 system an exciting prospect for additional follow up,” states Emily Gilbert, a postdoctoral fellow at NASA’s Jet Propulsion Laboratory who led the work and presented the findings at the American Astronomical Society.
The star called TOI 700 is located in the constellation Dorado and is 100 light-years from our solar system. Cooler than our Sun, it is one of many red dwarfs found in our galaxy. In fact, they account for about 70% of all stars in the Milky Way. TOI 700’s habitable zone – an orbit close enough, and thus warm enough, to allow liquid water on the surface, a fundamental criterion for life to exist – now has two planets. Indeed, planet e becomes the second after planet d was discovered in 2020, making TOI 700 one of the few star systems with multiple habitable-zone planets known to astronomers. TOI 700 e takes 28 days to orbit its star and is 95% Earth’s size. In comparison, TOI 700 d orbits its star in 37 days.