Planet Hunters Find Another 'Earthy' Planet in Our Galactic Neighborhood

Posted April 20, 2017

The "super-Earth", which is around 1.4 times the size of Earth but seven times its mass, is rocky, temperate and orbits a quiet star in our galactic neighbourhood.

'We could hardly hope for a better target to perform one of the biggest quests in science - searching for evidence of life beyond Earth'. Astronomers say it is a particularly exciting discovery because it is in a "habitable zone" and could support life. But if LHS 1140b was able to withstand the brunt of its star's radiation, it's possible signs of life are lurking there.

Meanwhile, an asteroid nicknamed "The Rock" that could be big enough to devastate a country last night made its closest approach to Earth in 400 years.

Another bit of good news is that terrestrial planet LHS 1140b as seen from earth passes nearly directly in front of its star, and that makes it a lot easier to do follow up research that Dittmann and his colleagues are already planning.

In the constellation Cetus, it is 39 light years or 230 trillion miles away.

LHS 1140b's dense metal core, however, might mean that it was covered by an ocean of magma during its host star's insane youthful period.

Follow-up observations carried out by a range of telescopes, including the European Southern Observatory's HARPS instrument then went on to characterize the planet's mass, density, and orbital period.

In 2015, Dittman was going over some observation data of small red stars collected by two robotically controlled observatories, called the MEarth Project, when he spotted something promising.

Manchester United blow the Premier League title race wide open [GALLERY]
With Fabregas and Willian's introduction, Chelsea created a few chances but failed to keep them on target. We have to react in the right way.

As LHS 1140 is much smaller and cooler than our own star, it doesn't throw out anything close to the levels of radiation that our Sun is capable of emitting. In a 2013 study, another team of scientists had found that a planet orbiting an M dwarf star could have surface temperatures that allow liquid water, if it receives between 0.2 and 0.8 times the insolation that Earth receives from the Sun. In short, it means that a rocky planet is orbiting its star at a distance in which liquid surface water might exist. Details of the discovery are reported in the journal Nature. The planet was discovered in 2014 with the MEarth-South telescope array at Cerro Tololo Inter-American Observatory in Chile, using a method that measured the faint dimming of starlight as it passed across LHS 1140's disk.

But given the size and location of LHS 1140b, the planet is an obvious candidate for further research. Some estimates suggest they account for three-quarters of the stars in the galaxy. This planet's large size indicates that a magma ocean may have existed on its surface for eons, feeding steam into the atmosphere and replenishing the planet with water until well within the time the star had cooled to its current, steady glow.

Hearing the phrase "habitable exoplanet" inevitably conjures up visions of another planet like Earth, teeming with vast oceans, swaths of green lands, and a crisp, gaseous veneer that keeps the whole thing together.

"Right now we're just making educated guesses about the content of this planet's atmosphere", said Dittmann. If either of those telescopes can't quite suss it out, future telescopes like the James Webb Space Telescope might make it easier.

Several years ago he bought a $15,000 US-made 12-inch telescope to begin a search for new exoplanets.

"Right now we don't have measurements of LHS 1140b's atmosphere or the atmosphere on other M dwarf rocky planets, and so a lot of this work is based upon theory and calculations", says Dittmann.

Julien de Wit, one of the researchers that discovered the TRAPPIST-1 planets, agrees.