The discovery of seven Earth-sized worlds orbiting a star 40 light-years away is certainly exciting news for exoplanet hunters and enthusiasts. But with three of these planets in the habitable zone of the cool, dwarf star TRAPPIST-1, this new discovery is definitely increasing our odds of finding other life in our galaxy.
Experts say that finding multiple planets in the "Goldilocks zone" of a star is a great discovery because there can be even more potentially habitable planets per star than originally thought.
"Finding several potential habitable planets per star is generally great news for our search for life," Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University, said in an email. "In our own solar system, we have two planets in the Habitable Zone (Earth and Mars), and this new system has three planets in the Habitable Zone. So far, it holds the record for number of rocky planets in the HZ."
Even though these planets are Earth-sized, that doesn't mean they are Earth-like. But several research teams are planning follow-up observations, so that means the fun is just beginning.
"I think the detection of the new planets in the TRAPPIST-1 system is a groundbreaking discovery," said Thomas Barclay, director of the Kepler/K2 mission Guest Observer program. "This has given us an example of temperate planets in our own backyard that we will be able to study in the coming years. So many opportunities to learn new things in one planetary systems is extremely compelling. Following along with the study of these planets is going to be thrilling. Within a few years this planetary system will be the second best studied, after our own solar system."
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Sara Seager, a planet hunter and professor of planetary science and physics at Massachusetts Institute of Technology, said that since the discovery of TRAPPIST-1 astronomers have used every telescope available to conduct follow-up observations. The Spitzer Space Telescope was instrumental in making confirmation studies of these worlds, which is especially interesting since Spitzer was never designed to observe exoplanets.
The Hubble Space Telescope is screening the six innermost planets looking for evidence of atmospheres. These observations, in the infrared and performed with the Wide Field Camera 3, will provide further information about the nature of the planets. In addition, Hubble's Space Telescope Imaging Spectrograph already observed the two innermost planets in the ultraviolet to determine the amount of irradiation they receive from their parent star.
But the best observatories for finding out more about these worlds - especially for determining their habitability - have yet to be launched.
"Looking for atmospheric bio-signatures - meaning the presence of ozone that would shield the surface and indicate biology in combination with a reduced gas like methane - could be detected with the James Webb Space Telescope, which will launch next year," Kaltenegger said.