With the discovery of seven Earth-sized planets orbiting a dwarf star, we are on the right track to find another habitable system! What makes this discovery by NASA’s Spitzer Space Telescope special is that this is the first time that a series of Earth-sized planets have been found around a single star, hence setting a new record for seemingly habitable planets around a single star outside our solar system.
All seven planets may have water in the liquid state and be habitable in the future with the chances being higher in at least three of them, which are located in the habitable zone. At a distance of about 40 light-years (235 trillion miles) from Earth, the system of planets is comparatively close to us and is a part of the Aquarius constellation. However since they are located outside our solar system, they are known as in exoplanets in scientific circles.
In May 2016, using TRAPPIST, a Chile-based Telescope researchers had discovered three planets in this solar system. Then the scope of research was widened and Spitzer along with assistance from several ground-based telescopes validated the existence of two of these planets and additionally found five more, thus increasing the number to seven. The system has since been named as TRAPPIST-1.
The Spitzer data allowed researchers to accurately measure the size of these seven exoplanets and develop an estimate on masses and densities of them. It has been deemed that the exoplanets will likely be rocky in nature and further observations need to be done to determine the availability of water and of liquid water in general. However the details about the seventh exoplanet are yet to be figured about, while some scientists opining that it could be an icy, “snowball” world, but things can only be verified after proper research has been done.
Also what makes this discovery special is that this is the first time Earth-sized planets have been found orbiting an ultra-cool dwarf, TRAPPIST-1 star. The star is much different as compared to our Sun, with it being quite smaller than our Sun. Even though the planets are more or less similar in size compared to Earth, the TRAPPIST-1 star is much different with only about one-twelfth the mass of our Sun and is just about 8 percent in size as compared to our Sun. Also, the surface temperature of it is a cool 4150 degree Fahrenheit as compared to the 10,000 degree Fahrenheit that our Sun displays. This makes it possible for the planets to be closer to the star, much closer than Mercury is to our Sun. Also, the planets may be tidally locked to the star, meaning that the same side of the planet faces the star at all times, hence having permanent day on one side, and permanent night on the other. With the distance between the star and the planets less, another two interesting facts are that these planets can be seen if one was standing on the surface of other, and these planets complete revolution around the Star at much faster pace, with the fastest taking only 1.5 days and slowest taking 20 days only!
Photo Courtesy – NASA
What made Spitzer the perfect choice for the task was that Spitzer is an infrared telescope trailing Earth while orbiting the Sun and the TRAPPIST-1 star glows brightest in infrared light. TRAPPIST-1 was monitored for over 500 hours by Spitzer. Because of Spitzer’s position around the orbit, it is useful in observing transits of planets going around the host star to find out about the system. This technique is what was used to find out information about the TRAPPIST-1 system.
According to Sean Carey, who is the manager of NASA’s Spitzer Science Centre in California, “Spitzer will continue to follow up on the system to help refine our knowledge of the exoplanets so that other telescopes can follow up too in the bid to unravel more secrets”. He also added that mission is one of the most exciting results he had seen in the 14 years of Spitzer operations.
NASA has also put Hubble Telescope on the mission to find out more about the Earth-sized exoplanets within the habitable zone. Spitzer, Hubble, and Kepler will be used to ensure follow-up studies with help of NASA’s James Webb Space Telescope that will be launching in 2018. With more integrated sensors, Webb will be able to provide us with a clearer picture.
It is also being speculated that the exoplanets may help the scientists in better understanding about planets that can harbour life even if these exoplanets turn out to be lifeless. Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate said in a statement, “This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life.”He continued, saying, “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.”
With the discovery, the space community seems quite abuzz, and with all the research going on to understand the system, a home away from Earth may not seem like a far-fetched dream in the future to come.