Using data from NASA’s Transiting Exoplanet Survey Satellite, Scientists have discovered an exoplanet roughly the size of Earth orbiting around a faraway star — within the habitable zone, meaning it could host liquid water on its surface.
The planet, called TOI 700 e, is the fifth discovered in the TOI 700 system, at 100 light-years away in the Dorado constellation.
The planet was discovered by NASA’s Transiting Exoplanet Survey Satellite (TESS) a space telescope designed to search for planets outside of our solar system, including those that could support life. Scientists confirmed that TOI 700 e is in the habitable zone of its star, also referred to as the “Goldilocks zone,” where temperatures are mild enough to potentially support liquid water and, therefore, life.
TOI 700 Star system
TOI 700 is a red dwarf star, which is smaller and cooler than our Sun — 40% the mass, 40% the radius and 55% of sun´s temperature, located 101.4 light-years away from Earth in the southern constellation Dorado. The system hosts five exoplanets (planets TOI 700 b, c and d were previously discovered) all five exoplanets may be tidally locked to TOI 700 which means they spin only once per orbit such that one side always faces the star, just as one side of the Moon is always turned toward Earth. Planet d also orbits in the habitable zone. But scientists needed an additional year of TESS observations to discover TOI 700 e.
If the star was a little closer or the planet a little bigger, we might have been able to spot TOI 700 e in the first year of TESS data,
said Ben Hord, a doctoral candidate at the University of Maryland, College Park and a graduate researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
But the signal was so faint that we needed the additional year of transit observations to identify it.
This is one of only a few systems with multiple, small, habitable-zone planets that we know of,
said Emily Gilbert, a postdoctoral fellow at NASA’s Jet Propulsion Laboratory in Southern California who led the work.
That makes the TOI 700 system an exciting prospect for additional follow up. Planet e is about 10% smaller than planet d, so the system also shows how additional TESS observations help us find smaller and smaller worlds.
TOI 700 e
The exoplanet, TOI 700 e, orbits this star at a distance of about 20 million miles, which is about 20% closer than Earth’s orbit around the Sun. Because of its proximity to the star, the planet completes an orbit in just 28 Earth days.
One of the most exciting aspects of the discovery of TOI 700 e is that it is one of the nearest known exoplanets in the habitable zone of its star. This means that it is in a prime location to potentially support life, as it is not too close to its star to be too hot, and not too far away to be too cold. Additionally, TOI 700 e is also one of the smallest known exoplanets in the habitable zone of its star, with a size similar to that of Earth — 95 per cent the size of our planet.
Due to its size, it is expected to have a solid surface and a thick atmosphere, which could potentially support life in a similar way to Earth.
TOI 700 e proves that TESS can help “us find smaller and smaller worlds.”
TESS has created imaging for about 75% of the sky and found 66 new worlds beyond the Earth’s solar system.
finding other systems with Earth-size worlds in this region helps planetary scientists learn more about the history of our own solar system. Follow-up study of the TOI 700 system with space- and ground-based observatories is ongoing and may yield further insights into this rare system.
Watch to learn about TOI 700 e
📷Credits: NASA/JPL-Caltech/Robert Hurt/NASA’s Goddard Space Flight Center