NASA has announced the discovery of seven Earth-like, or “rocky,” exoplanets in orbit around the red dwarf star TRAPPIST-1, three of which reside in the habitable zone. This zone is often referred to as the “Goldilocks Zone” because it is the right temperature to support carbon-based 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 agency’s 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.”
TRAPPIST-1 resides only about 40 light-years away from Earth, making it an easy target for planet hunters. It gets its name from a telescope in Chile named The Transiting Planets and Planetesimals Small Telescope (TRAPPIST), which provided data that led to the discovery of three of the planets around TRAPPIST-1.
Further observations were made using the Spitzer telescope and several ground-based telescopes such as the European Southern Observatory’s Very Large Telescope. These rocky exoplanets have orbital periods (“years”) ranging from 1.5 Earth days to an estimated 20 days and the closest planet is estimated to be only 0.011 astronomical units from its parent star.
The exoplanets are currently labeled “B” through “H”, though the panelists making the announcement on NASA TV did joke about possibly naming them after Belgium beers. Planets E, F and G are in the habitable zone. E and F are about the same size as Earth and G is about 13% bigger. It’s not yet known if any of these planets have life-friendly atmospheres or moons, but if one could stand on a planet in TRAPPIST’s habitable zone, the other planets would likely appear as a concrete world instead of a “wandering star.”
Science Teams Will Make Further Observations
The panel of scientists that made the announcement on NASA TV expressed enthusiastic anticipation of the planned launch of the James Webb Telescope, which will enable more detailed observations of these exoplanets’ composition, including the makeup of any atmospheres that they might have. Meanwhile, science teams will continue to make observations using existing telescopes such as the Kepler space telescope.
Future observations will likely answer remaining questions, including the exact nature of the outermost Planet H and a refinement of the understanding of its orbit. Early data suggests that the outermost planet may contain high concentrations of ice. Because all seven of these planets are so close together, they are likely to interact with one another with their gravitational pull. Their proximity to their parent star suggests that they may have formed farther out and then migrated inward to their current orbits.
Kepler will conclude its observations in March and the data will be made available on the Barbara A. Mikulski Archive for Space Telescopes, where existing data related to the discovery and continued observation of these exoplanets already resides.
Scientists involved in the discovery and continued observations of the planets around TRAPPIST-1 participated in a Reddit AMA after the announcement was made. Panelists included:
- Giada Arney, astrobiologist, NASA Goddard Space Flight Center
- Natalie Batalha, Kepler project scientist, NASA Ames Research Center
- Sean Carey, paper co-author, manager of NASA’s Spitzer Science Center at Caltech/IPAC
- Julien de Wit, paper co-author, astronomer, MIT
- Michael Gillon, lead author, astronomer, University of Liège
- Doug Hudgins, astrophysics program scientist, NASA HQ
- Emmanuel Jehin, paper co-author, astronomer, Université de Liège
- Nikole Lewis, astronomer, Space Telescope Science Institute
- Farisa Morales, bilingual exoplanet scientist, NASA Jet Propulsion Laboratory
- Sara Seager, professor of planetary science and physics, MIT
- Mike Werner, Spitzer project scientist, JPL
- Hannah Wakeford, exoplanet scientist, NASA Goddard Space Flight Center
- Liz Landau, JPL media relations specialist
- Arielle Samuelson, Exoplanet communications social media specialist
- Stephanie L. Smith, JPL social media lead