NASA telescope reveals largest batch of Earth-size, habitable zone planets around a single star
UCLan researcher included in international research team
NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are located in an area called the habitable zone, where liquid water is most likely to thrive on a rocky planet.
The system sets a new record for greatest number of habitable zone planets found outside our solar system. Any of these seven planets could have liquid water, key to life as we know it.
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. 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, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
The new results were published Wednesday in the journal Nature, and announced at a news briefing at NASA Headquarters in Washington.
"By precisely monitoring the brightness of the host star, we have been able to detect the planets as they pass in front of the star and block a small amount of light."
Dr Daniel Holdsworth, a postdoctoral research associate at the University of Central Lancashire’s (UCLan) Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, is one of the European scientists involved in the project and monitored the TRAPPIST-1 system in an attempt to measure the transit of the outer most planet in the system.
He said: “The TRAPPIST-1 planetary system hosts the largest number of exoplanets close enough to their parent star that liquid water might exist. By precisely monitoring the brightness of the host star, we have been able to detect the planets as they pass in front of the star and block a small amount of light. By knowing how big the star is, and how much light is blocked, we can calculate how big the planets are. The planets are small and rocky and are comparable in size to the Earth. At just 40 light years away, this makes TRAPPIST-1 a prime target to study the atmospheres of exoplanets to search for traces of water, and even life, in this nearby solar system.
“As the TRAPPIST-1 star is very cool, just 2,550 degrees (compared to the Sun at 6,000 degrees) the team used NASA’s Spitzer space telescope, which is very sensitive to red light, to monitor the star for 500 hours. These data, in conjunction with data collected at some of the largest telescopes around the world, lead to this fantastic discovery.”