Astronomers have announced the discovery of a seven-planet system orbiting a dim star in the constellation of Aquarius, located 39.4 light years from the earth. The findings are based upon very sensitive dips in the light of the star when a planet crosses in front of it from our perspective.
The star, a red dwarf, identified as 2MASS J23062928−0502285 with a high proper motion and radial velocity was observed using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) being a 0.6 meter, 24 inch aperture instrument at the La Silla Observatory (European Southern Observatory). The discovery of two planets transiting the star was first reported in May 2016. Numerous Earth-based studies with considerably larger telescopes have verified the initial report.
The Spitzer Space Telescope confirmed the first two planets and located an additional four more, bringing the total six; all authenticated by the observations of multiple transits.
A seventh planet is suspected and likely after researchers observed a single light intensity drop but it will take the team of astronomers time to record more data of the seventh object to be sure. In contrast, Spitzer has measured over thirty-seven transits of the remaining six planets. The discovery is quite remarkable mostly because it is such faint star, being almost 18.8 magnitude in brightness.
The TRAPPIST System consists of Trappist 1a being the host red dwarf star, with planets designated by the letters “b” through “h”, representing the planets one through seven. All six of the confirmed planets are in close proximity to their star, and would easily fit inside the orbital distance of the planet Mercury if they were inside our solar system. Therefore the durations of the seven planets orbital periods are between 1.5 to 12.3 days meaning one year is only several days long. The red dwarf puts out less than one thousandth the light of our sun, yet several planets appear to be located within the “Goldie lock’s Zone”, meaning they possibly could harbor liquid water. Interestingly the planets are close to the size of our own earth with a similar mass.
The frequency of observable transits suggests that each planet is tidally locked to the star, with one side that always faces the sun and the other side that receives no direct sunlight. The moon is tidally locked in orbit to the earth always showing the same side facing us, (However, it does rotate once every 27 days closely matching its orbital period around the earth of approximately the same period of time). Tidal locking could cause a concern for the existence of life. There would be a lack of consistency in the temperatures, with hot and cold spots on the surface of the planets, resulting in less favorable circumstances to support life as we understand. Spectroscopic analysis will in the future help determine their atmospheric compositions as we explore the matter in greater detail.
During a recent press conference, one of the astronomers believed that planet 1f (planet 5) of the TRAPPIST-1 SYSTEM would be a favorite in the search for extra-terrestrial life. Much of the of the light that reaches the TRAPPIST-1 system comes in the form of infrared and would be warm resembling the type of energy you can feel on your skin more that you can see visually. The view of the star would be three times larger than the sun as it would appear in the planet’s sky and would be of a salmon color. A very beautiful spectacle, indeed.
The 0.6 meter 24 inch telescope used for the discovery is manufactured by: