Newly-discovered exoplanet could be best clue to life out there

Posted April 20, 2017

There might be another Earth out there, and its name is LHS 1140b.

Wednesday, another red dwarf star is making headlines with the announcement of a "super earth" found orbiting around the small red star LHS 1140.

In this instance, as LHS 1140b is so big - approximately 1.4 times the size of Earth - the radiation would have been ineffective as the planet would have been covered by heaps of lava in its infancy, according to the study published in the journal Nature.

Jason Ditton at the Harvard-Smithsonian Center for Astrophysics said the new exoplanet, known as LHS 1140b, was the most exciting he had seen in 10 years.

This new big planet is rocky, like Earth.

Recently, NASA announced the discovery of a star known as TRAPPIST-1 which was found to have seven planets orbiting it.

Located just 40 light-years away, the planet was found using the transit method, in which a star dims as a planet crosses in front of it as seen from Earth.

The new planet is 40 percent wider than Earth but it has 6.6 times Earth's mass, giving it a gravitational pull three times stronger, according to Charbonneau said.

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"Given its large surface gravity and cool insolation, the planet may have retained its atmosphere despite the greater luminosity (compared to the present-day) of its host star in its youth", the study authors wrote.

In the case of LHS 1140b, the starlight is bright, the orbit is only 25 days and the planet is seen nearly edge-on from Earth. Therefore, some or all of the others also might not be rocky.

But an atmosphere around a habitable M-dwarf planet has never been spotted. Large, next-generation telescopes will be needed to tease out these subtle signals. "This star that LHS 1140b orbits seems to be quiet, so it's not going to damage the planet's atmosphere or anything on its surface", Dittmann explained. Every 25 days, the exoplanet makes a complete revolution around its parent star, unlike Earth which needs 365 days. The amount of sunlight this super-Earth receives is about half as much as Earth.

Since then, astronomers have recorded more than 3,500 worlds in 2,675 star systems. Being in a good orbital distance means nothing unless the water has an atmosphere that can trap it down and actually keep the planet temperate enough for surface water to thrive. This ocean may have infused the atmosphere with steam for a prolonged period, which would have effectively replenished the planet's water supply. If the planet gets bombarded by too much high-energy radiation, at least we know to look elsewhere for alien life. "We don't have atmospheric measurements right now, but the star behaves nicely so that it's not ruling out anything", says Dittman.

The planet was discovered by observing the tiny reduction in the light from the star when the planet passed in front of it. Mr Tan said the minute dip in light was like "observing a candle burning in Albany from Perth". And that means there's a better chance that this planet may be holding onto some valuable chemicals, like organic molecules and water. The star is "almost as bright as you could possibly get without making life hard", he says.

LHS 1140 b was discovered using the MEarth-South telescope array at Cerro Tololo Inter-American Observatory. These star types have become popular targets for exoplanet hunters, since they're also common throughout the galaxy and it's easier to spot planets around them.

The red dwarf star LHS 1140 lies in the faint constellation of Cetus (The Sea Monster). CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.