Washington: In a major boost to the search for alien life outside our solar system, astronomers have spotted the first known system of seven Earth-sized planets around a single star, NASA said.
All of these seven planets could have liquid water -- key to life as we know it -- under the right atmospheric conditions, but the chances are highest with three of the plants which are located in the habitable zone, according to the researchers.
"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 NASA's Science Mission Directorate in Washington.
At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius.
Because they are located outside of our solar system, these planets are scientifically known as exoplanets.
This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile is a small, dim celestial body in the constellation Aquarius. It is located about 40 light years away from Earth.
Researchers said the proximity of the system, combined with the proportionally large size of its planets compared to the small star, make it a good target for follow-up studies. They hope to scan the planets’ atmospheres for possible chemical fingerprints of life.
“I think that we’ve made a crucial step towards finding if there is life out there,” University of Cambridge astronomer Amaury Triaud told reporters on a conference call on Tuesday.
The discovery, published in this week’s issue of the journal Nature, builds on previous research showing three planets circling TRAPPIST-1. They are among more than 3,500 planets discovered beyond the solar system, or exoplanets.
Researchers have focused on finding Earth-sized rocky planets with the right temperatures so that water, if any exists, would be liquid, a condition believed to be necessary for life.
The diameter of TRAPPIST-1 is about 8 percent of the sun’s size. That makes its Earth-sized planets appear large as they parade past.
In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system.
Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, NASA's Spitzer space telescope confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them, allowing their density to be estimated.
Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky, according to the new results published on Wednesday in the journal Nature.