New Planetary System TRAPPIST-1 Found in 2017
NASA in February 2017 announced their discovery of an exoplanet system that could sustain organic life. This planet system, situated about 235 trillion miles from Earth, in the constellation Aquarius, consists of seven Earth-earth size planets around a single star. According to scientists, three out of these seven planets are said to be located in the habitable zone and could thus sustain life. This exoplanet system is known as TRAPPIST-1 and is named after the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. Given below (Figure 1) is a NASA artist’s rendering of the planetary system.
Figure 1: Artist’s concept of TRAPPIST-1 planetary system
The star in this planetary system is also known as TRAPPIST-1 star. This has been identified as an ultra-cool dwarf. The planets do not have proper names; they are known by letters, “b” – “h.” Since the star of this system is a dwarf star, it has a lesser temperature than the sun, and the liquid water can survive on planets that are closer to the star. Three of these seven stars – e, f, and g – are located in the habitable zone, and there is a possibility that these planets can sustain life.
Using data from Spitzer telescope, the NASA scientists have determined the sizes of the planets and developed estimates of the masses and densities of six of them. Based on these data, it has been deducted that all planets in this exoplanetary system are likely to be rocky. The details of the seventh planet have not yet been estimated.
Figure 2 displays available data about these seven planets in comparison to planets in our solar system. These details include orbital period, diameters, masses and distances from the host star.
Figure 2: Details of the exoplanets in comparison to planets of the solar system.
The seven planets in TRAPPIST-1 are similar to the size of the Earth. They are situated very close to each other. Geological features and clouds of neighbouring planets can be seen from the surface of one planet. They are also closer to their sun than planets in the solar system. If Trappist-1 were the Sun, all seven planets would be inside Mercury’s orbit.
It is also said that these planets may be tidally locked to their star. This means that the planets’ orbital period matches its rotational period. Thus, the same side of the planet is always facing the star, making each side either perpetual night or day.
The discovery of this planetary system is a huge leap forward in the search for habitable worlds. It gives astronomers a chance to study and redefine their knowledge on exoplanetary systems. Since cool dwarf stars are more common in the universe, it is also expected that researching them will lead to the discovery of more Earth-like planets.
Reference:
1. Northon, Karen, editor. “NASA Telescope Reveals Record-Breaking Exoplanet Discovery.” NASA, National Aeronautics and Space Administration, 22 Feb. 2017, www.nasa.gov/press-release/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around. Accessed 24 Feb. 2017.
Image Courtesy:
1. “PIA21425 – TRAPPIST-1 Statistics Table” By NASA/JPL-Caltech (Public Domain) via Commons Wikimedia
2. “PIA21422 – TRAPPIST-1 Planet Lineup, Figure 1.” By NASA/JPL-Caltech (Public Domain) via Commons Wikimedia