Three ‘Earth-like’ planets discovered

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Three New Earth-Like Planets orbiting Star TRAPPIST 1 Might Be Our Best Bet For Finding Life

2 May 2016

The three Earth-like planets around the Star TRAPPIST-1 were discovered using transit method, only detection method currently available to us.

The Transit method looks for dims in star light as planets pass in front of it, the amount of dimming determines the size of the planet and location of the planet.

Belgian astronomers discovered the three potentially habitable Earth-like planets orbiting an ultracool dwarf star, named TRAPPIST-1, about 40 light-years from Earth. These are some of the smallest exoplanets ever discovered, with a radius only slightly bigger than Earth’s, and they are the first planets discovered around an ultracool dwarf – a dim star not much bigger than Jupiter. Their results are published in Nature.

The most exciting thing about this discovery, made by the Belgian TRAPPIST telescope as the planets passed in front of the star, is that these planets are close enough for us to study. Many of the other potentially habitable worlds we’ve found are much further away and around much brighter stars, making them more difficult to observe.

“These are the first planets similar in size and temperature to Earth and Venus for which we can study the atmospheric composition in detail, and really constrain the surface conditions and habitability,” lead author Dr. Michaël Gillon from the University of Liège told IFLScience.

At first glance, the system might not seem that promising. Two of the planets, TRAPPIST- 1b and c, have years lasting about 1.5 and 2.4 Earth days respectively, meaning they orbit very closely, while TRAPPIST-1d has a less well determined period in the range of 4.5 to 73 days. However, the star has a surface temperature of only 2,550 Kelvins (2,277°C / 4,130 °F ), so they are unlikely to be inferno worlds. Instead, they could be quite the opposite.

The closest two planets receive no more than four times the amount of radiation received by Earth, while the furthest planet likely receives less. This puts the planets at the edges of the star’s habitable zone, the region in which liquid water can exist. It’s not certain if the planets are solid, but TRAPPIST-1 is rich in heavy elements, which indicates a suitable evironment for rocky planets to form.

The planets have a radius of 1.11, 1.05, and 1.16 times that of Earth, which combined with their locations strongly indicates that these objects possess some of the right conditions for life. The planets’ temperatures could range from slightly higher than water’s boiling point to well below freezing.

Tune used in this video is: Surfing Llama and artist name is Bird Creek.

By Michael McLaughlin in the USA:

Astronomers Find 3 ‘Temperate’ Planets That May Support Life

The Earth-like planets are the first ones found orbiting an ultracool dwarf star.

05/02/2016 06:30 pm ET

Astronomers say three recently discovered planets similar to Earth’s size and temperature may have conditions that could sustain life.

An international team observed the three planets orbiting a reddish, ultracool dwarf star, once thought too dim to anchor a solar system. Their research, published in the journal Nature on Monday, said these are the first planets ever seen orbiting an ultracool dwarf star.

“Systems around these tiny stars are the only places where we can detect life on an Earth-sized exoplanet with our current technology,” co-author Michael Gillon, of the University of Liege in Belgium, said in a statement. “So if we want to find life elsewhere in the universe, this is where we should start to look.”

Previously, scientists have only found exoplanets — planets that do not orbit our sun — with conditions unlike Earth’s. In November, for instance, a rocky, Earth-sized planet was found 39 light years away, but its temperature was estimated at 300 degrees to 600 degrees. The discovery of the three potentially habitable planets may encourage researchers to look more closely at the huge numbers of ultracool dwarf stars.

The three planets orbit a star in the Aquarius constellation named Trappist-1, which is about the size of Jupiter. But the planets are close enough to the star to have “temperate” conditions on their surface, MIT researcher Julien De Wit told NPR.

The planets are about 40 light years from Earth — making them nearby in galactic terms.

The nearness and their star’s dimness will make it easier for scientists to study the exoplanets, which are often tough to analyze when orbiting a distant, bright star.

Each of the planets has a side that’s perpetually in daylight and another side that’s completely dark. The most likely region to support life would be along the line separating day and night, where temperatures would be less extreme, according to Gizmodo.

The nearest two planets complete their revolutions around the star in 1.5 days and 2.4 days. Scientists haven’t completely charted the last planet’s orbit, but it could take from 4.5 to 72.8 days.

Astronomers don’t yet know what the planets are made of, and want to check for liquid water, the foundation for life.

Researchers may get further information about the atmospheric conditions after monitoring what happens to the star’s light when the planets pass in front of it, according to The Verge. The presence of different gases on the planets will cause the light to behave differently.

The team used the Trappist telescope in Chile to study 60 stars too dim to see with the naked eye, according to Gizmodo. NASA’s planned launch of the James Webb Space Telescope in 2018 could be useful, as one of its missions is to search for solar systems supporting life.