This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets' diameters, masses and distances from the host star, as of February 2018. Credit: NASA/JPL-Caltech

Exoplanet discovery

In a press release on February 22, 2017, NASA announced the discovery of the most Earth-sized planets found in the habitable zone of a single star, called TRAPPIST-1. This system of seven rocky worlds–all of them with the potential for water on their surface–is an exciting discovery in the search for life on other worlds. There is the possibility that future study of this unique planetary system could reveal conditions suitable for life.

In February 2018, closer study of the seven planets suggested that some could harbor far more water than the oceans of Earth, in the form of atmospheric water vapor for the planets closest to their star, liquid water for others, and ice for those farthest away. The new study pinned down the density of each planet more precisely, making TRAPPIST-1 the most thoroughly known planetary system apart from our own.


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Exoplanet surface in 360 VR

Use your mouse or fingertip to experience a 360 view. On mobile, move your phone to see sky, ground and horizon. This is an artist's interpretation.

An artist's illustration of TRAPPIST-1d takes you to the surface of the third planet from the red TRAPPIST-1 star. From here, the star looms larger than our sun and its light casts a red glow across the sky. Look up, and you may catch a glimpse of its six sister planets, as visible as our moon is from Earth. View on YouTube

Planet hop from TRAPPIST-1e

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An artist's fantasy of the surface of TRAPPIST-1e, a stop on a tour of this seven-world system.

Take a trip with the Exoplanet Travel Bureau to the fourth planet in the TRAPPIST-1 system, TRAPPIST-1e, a world swimming in water in perpetual twilight. Its sister planets gracefully light up the sky, promising another adventure just a hop away.
Download your own free poster

Interact with the TRAPPIST-1 system in 3D

You can fly through the TRAPPIST-1 planets and see an artist's concept of the surfaces on your phone or with a desktop app. Compare each planet to Earth or Jupiter, compare the TRAPPIST-1 system to our solar system, and see how far the habitable zone extends.

  • With the touch of a screen or the click of a mouse, you can visit the newly discovered TRAPPIST-1 system in the our exoplanet atlas. The New Worlds Atlas contains every exoplanet discovery, powered by NASA's Exoplanet Archive, the official database used by professional astronomers engaged in exploring new worlds.


  • Get set for launch. Download “Eyes on Exoplanets” and it will fly you to any planet you wish—as long as it's far beyond our solar system. This fully rendered 3D universe is scientifically accurate, allowing you to zoom in for a close look at more than 1,000 exotic planets known to orbit distant stars, including the TRAPPIST-1 system. The program is updated daily with the latest finds from NASA and ground-based observatories around the world.

Latest images and videos

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    This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets' diameters, masses and distances from the host star, as of February 2018. Credit: NASA/JPL-Caltech. Full resolution
  • Trappist-1 Planets Infographic
    This chart shows, on the top row, artist concepts of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii, masses, densities and surface gravity as compared to those of Earth. Credit: NASA/JPL-Caltech. Full resolution
  • Comparison w solar system
    All seven planets discovered in orbit around the red dwarf star TRAPPIST-1 could easily fit inside the orbit of Mercury, the innermost planet of our solar system. In fact, the proportions of the TRAPPIST-1 system look more like Jupiter and its moons. Credit: NASA/JPL-Caltech. Full resolution
  • TRAPPIST-1 beauty shot
    This illustration shows the seven Earth-size planets of TRAPPIST-1. The image does not show the planets' orbits to scale, but highlights possibilities for how the surfaces of these intriguing worlds might look. NASA/JPL-Caltech. Full resolution
  • Density plot
    This graph presents known properties of the seven TRAPPIST-1 exoplanets (labeled b through h), showing how they stack up to the inner rocky worlds in our own solar system. Credit: NASA/JPL-Caltech. Full resolution

Images from 2017

  • This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses and distances from the host star, as of Feb 2017. Full resolution
  • The TRAPPIST-1 system consists of seven Earth-sized planets orbiting a red dwarf star. Full resolution
  • This chart shows, on the top row, artist concepts of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii and masses as compared to those of Earth, as of Feb 2017. Full resolution
  • This artist's concept allows us to imagine what it would be like to stand on the surface of the exoplanet TRAPPIST-1f, located in the TRAPPIST-1 system in the constellation Aquarius, as of Feb 2017. Full resolution
  • This data plot shows infrared observations by NASAs Spitzer Space Telescope of a system of seven planets orbiting TRAPPIST-1, an ultracool dwarf star, as of Feb 2017. Full resolution
  • Three of the TRAPPIST-1 planets – TRAPPIST-1e, f and g – dwell in their star’s so-called “habitable zone,” as of Feb 2017. Full resolution
  • A comparison of the TRAPPIST-1 system to our solar system. The close orbits of the TRAPPIST-1 planets are reminiscent of Jupiter and its system of orbiting moons, as of Feb 2017. Full resolution
  • Any of the TRAPPIST-1 planets could have water on them, though the three in the habitable zone are more likely to have liquid water, as of Feb 2017. Full Resolution

Trappist-1 system Spitzer findings

Before and after the discovery of four new planets

Related Videos:

  • Since 2017, we knew the TRAPPIST-1 system had seven Earth-sized planets. Now in 2018, a study using new data – including extensive observations by NASA's Spitzer and Kepler space telescopes – has provided more information about this amazing system.

  • Astronomers using the Hubble Space Telescope have conducted the first spectroscopic survey of Earth-sized planets in the TRAPPIST-1 system’s habitable zone.

  • See the TRAPPIST-1 gallery of art and animations at Caltech's Spitzer telescope site, as of Feb 2017.

  • Archived footage of the NASA news conference announcing the discovery of the seven TRAPPIST-1 planets on February 22, 2017.

  • This video features interviews with the scientists who discovered the system of seven planets orbiting TRAPPIST-1, an ultra-cool dwarf star.

  • How would life be different around a red star? While we don’t know if there is life on the TRAPPIST-1 planets, we do know that any life discovered there would likely be very different from life on Earth.

  • This video details a system of seven planets orbiting TRAPPIST-1, a discovery of the Spitzer Space Telescope, operated by NASA's Jet Propulsion Laboratory in Pasadena, California.

  • This animation visualizes the change in light as each planet passes in front of its star. The study established the planets' size, distance from their sun and, for some of them, their approximate mass and density.

  • How do we know what the air is like on planets we haven't visited? This James Webb Space Telescope video explains how to see air from 150 light-years away.

  • An animation of the seven TRAPPIST-1 planets transiting in front of their red dwarf star.

  • This video depicts artist's concepts of each of the seven planets orbiting TRAPPIST-1, an ultra-cool dwarf star. The planets appear in the order of innermost to outermost planets.

  • This animation portrays NASA's Spitzer Space Telescope in space.

Panelists from the 2017 news conference

Michael Gillon

Michael Gillon

Title: Research Associate at the Belgian Fund for Scientific Research (F.R.S.-FNRS)

Institution: University of Liège, Belgium

Role in TRAPPIST-1 discovery: Initiator and lead.

Other missions/topics worked on: The detection and characterization of transiting exoplanets. PI of the projects TRAPPIST and SPECULOOS. PI of many Spitzer and ESO programs, and Co-I of the CoRoT and CHEOPS exoplanet space missions.


Sean Carey

Sean Carey

Title: Manager, Spitzer Science Center

Institution: IPAC/Caltech.

Role in TRAPPIST-1 discovery: Co-author of paper.

Other missions/topics worked on: Spitzer, NEOCam and WFIRST. Additional scientific work includes the physics of the interstellar medium and studying the galactic distribution of planets via microlensing.


Thomas Zurbuchen

Thomas Zurbuchen

Title: NASA Associate Adminstrator, Science Mission Directorate

Institution: NASA, Washington, D.C.

Other missions/topics worked on: Please see Dr. Zurbuchen’s biographical page.


Sara Seager

Sara Seager

Title: Professor of Planetary Science, Professor of Physics

Institution: MIT

Other missions/topics worked on: TESS Deputy Science Director. PI ASTERIA. Expert in biosignature gases in the search for life on exoplanets.


Nikole Lewis

Nikole Lewis

Title: Assistant Astronomer/James Webb Space Telescope Project Scientist

Institution: Space Telescope Science Institute

Role in TRAPPIST-1 discovery: I co-lead the investigation of the TRAPPIST-1 planets with Hubble’s Wide-Field Camera 3 (WFC3) instrument.

Other missions/topics worked on: Specializes in understanding circulation and cloud/haze formation in exoplanet atmospheres. Currently a Deputy-PI of a WFIRST Coronagraphic Instrument (CGI) Science Investigation Team (SIT), the JWST Project Scientist at STScI, and part of a team (PI Sarah Horst, JHU) creating exoplanet hazes in the lab.

Related Articles

Science results:

  • Go here to read "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1," published in Nature.

  • A short fictional account published in Nature imagines a first-person narrative account of life on the TRAPPIST-1 planets.

  • The official website from the scientists behind the discovery, this gives a brief introduction to the system.

  • NASA exoplanet experts and the astronomers who discovered the TRAPPIST-1 planets answered questions about the seven Earth-sized worlds on February 22, 2017.