TESS satellite uncovers its 'first nearby super-Earth'

Pablo Tucker
August 1, 2019

The group of astronomers found the exoplanet in a constellation called Hydra which is around 31 light-years from Earth, as per NASA yesterday, July 31. If made of rock, this planet may be around twice Earth's size.

Researchers said that GJ 357 d has a thick atmosphere, so it could maintain liquid water on the surface like planet Earth could.

The potentially habitable planet due to loads of water assumed to be stored in its depths, and two neighbouring worlds were discovered making the rounds around a dwarf star, which is around a third the size and mass of our own Sun and 40% cooler. They showed that the distant solar system - with a diminutive M-type dwarf sun, about one-third the size of our own sun - harbors three planets, with one of those in that system's habitable zone: GJ 357 d.

Using NASA's Transiting Exoplanet Survey Satellite (TESS), astronomers discovered a potentially habitable world outside of the solar system.

TESS paid attention to the star dimming every 3.9 days - a fact that may point to the exoplanet possibly transiting its face.

"This system is exactly what TESS was created to find - small, temperate planets that pass, or transit, in front of an inactive host star, one lacking excessive stellar activity, such as flares", Maximilian Günther, lead researcher on the project, said in a NASA news release.

Exoplanet GJ 357 c sizzles at 260 degrees Fahrenheit and has at least 3.4 times Earth's mass. "Although it can not host life, it is noteworthy as the third-nearest transiting exoplanet known to date and one of the best rocky planets we have for measuring the composition of any atmosphere it may possess".

Located about 31 light-years away, the super-Earth planet - named GJ 357 d - was discovered in early 2019 owing to TESS, a mission created to comb the heavens for exoplanets, according to their new modeling research in the Astrophysical Journal Letters.

Researchers studying the star GJ 357 were trying to confirm the existence of its first-discovered planet, GJ 357 b, when they noticed two other planets orbiting the same star.

GJ 357 d orbits its star every 55.7 days at a range of about 20 per cent of Earth's distance from the sun, it is claimed.

Follow-up observations and data collected by Earth-based telescopes dating back two decades led to the discovery of the planet's siblings, GJ 357 c and GJ 357 d.

This diagram shows the layout of the GJ 357 system.

In this case that's about five times closer to the star than Earth is to the Sun, but because this star is so much dimmer than the Sun, the planet actually receives less energy than Earth does. An orbiting planet produces a gravitational tug on its star, which results in a small reflex motion that astronomers can detect through tiny color changes in the starlight.

While TESS is an additional attempt to add more exoplanet candidates to its database, NASA's Kepler space telescope has observed more than 300,000 stars and found more than 4,000 exoplanet candidates since it launched in 2009. The findings, published in the journal Astronomy & Astrophysics, were presented Wednesday (local time) at an exoplanet conference in the city of Cambridge, Massachusetts.

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