Seven Earth-sized possibly habitable planets found in the TRAPPIST-1 star system

The NASA Spitzer Space Telescope found a new planetary system with record seven Earth-analog planets, three of them located firmly in the habitable zone.

This astonishing discovery sets the record of the most Earth-sized planets around a star outside our Solar system. There is a big chance for these planets to have liquid water – the prerequisite to life.

“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the Science Mission Directorate in Washington. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

They are located in the constellation Aquarius at around 40 light years away.

The exoplanetary system is named TRAPPIST for the The Transiting Planets and Planetesimals Small Telescope located in Chile. Researchers using this telescope announced last year that they found three planets in the system. Later observations from ground telescopes, helped Spitzer to confirm two of the planets, and found five new, increasing the overall number of planets to seven.

By using the data from Spitzer, scientists could measure the mass and density of the planets.

Based on this research, all the planets appear to be rocky. Further observations will determine if they have liquid water on the surfaces of the planets. The last seventh planet still has unknown mass and it might be a “snowball” world, but further observations are needed.

“The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star,” said Michael Gillon, lead author of the paper. “It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds.”

In stark contrast to our own star, TRAPPIST-1 is an ultra-cool dwarf. This means that planets must orbit very closely to their star to have liquid water on the surface. If you were to stand on one of the planets, you could see geographical features of the other neighboring worlds.

This means that the planets might be tidally locked, and the weather patterns would be far different that those we experience on Earth.

The infrared telescope Spitzer that trails the Earth while it orbits the Sun, was well-suited to finding this unbelievable discovery. It was in a very good position against the star to observe the transits of the planets and it did so for over 500 hours.

“This is the most exciting result I have seen in the 14 years of Spitzer operations,” said Sean Carey, manager of NASA’s Spitzer Science Center. “Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”

Following this discovery, NASA Telescope is going to screen those planets to assess if they are  puffy hydrogen planets, that are typical for gaseous worlds like Jupiter.

Last year, the astronomers of Hubble found no evidence of such gaseous atmospheres.

“The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets,” said Nikole Lewis, co-leader of the Hubble study.

The Kepler telescope also joins in this planet hunting in the TRAPPIST-1 system. It will make measurements of the star’s tiny changes when planets transit and will refine the current data about them. Finding  another planets is a possibility too.

The Spitzer,Kepler and Hubble telescopes will help with these studies until the James Webb Space Telescope launches in 2018.With far greater sensitivity, it will allow for observation of various gases in the atmospheres like methane,oxygen, ozone and many others, helping with the assessment of the planets habitability.



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