Scientists have found a previously lost planet, NGTS-11B, through a technique used for scanning exoplanets, according to a report from the University of Warwick.
The team, led by scientists from the University of Warwick in the U.K., also published their findings in the Astrophysical Journal Letters, last July 20. It was originally discovered back in 2018 through NASA's Transiting Exoplanet Survey Satellite (TESS) telescope.
However, NGTS-11b went undetected because of the TESS restrictions - the NASA telescope can only scan a portion of the sky for 27 days. With its transit method, a body is only detected as it passes in front of its star. Its scanning period means that bodies that move far slower can only be identified once it is in data logs. Therefore, NGTS-11b was dismissed as a single-transit event.
It was detected again by the Warwick-led team, who are pioneering a new technique for scanning other planets through the Next-Generation Transit Survey (NGTS) telescopes installed in Chile.
In their paper, the scientists noted that NGTS-11 is the first TESS single-transit event to be rediscovered through their method.
NGTS-11b, an exoplanet with a mass and size close to our own system's Saturn, orbits a sun five times closer compared to Earth and our sun. The new planet, while being relatively closer to its star, only has a temperature of 160°C, cooler than both Venus and Mercury.
A Step in Finding More Worlds Within the "Goldilocks Zone"
Although the average temperature recorded from exoplanet NGTS-11b is lower than Mercury and Venus, it is still too hot to support life, according to Dr. Samuel Gill of the University of Warwick's Physics Department. However, he noted that the rediscovered planet is "closer to the Goldilocks zone than many previously discovered planets, which typically have temperatures above 1000°C."
Dr. Daniel Bayliss, coauthor of the research paper, commented that it is exciting to see the Goldilocks zone within sight. Professor Pete Wheatley, also a coauthor from the University of Warwick, explained that the NGTS has twelve state-of-the-art telescopes, allowing them to monitor multiple stars for extended periods.
The Goldilocks zone, also known as the circumstellar habitable zone (CHZ) or the habitable zone, is a range of distance from a star with the right conditions to keep water in its liquid form. The ability to support liquid water is often viewed as a precursor to sustaining life. If a planet moves too close to its star, the planet becomes too hot for life as we know it; too far and the planet will be too cold.
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Its term is taken from the fairy tale "Goldilocks and the Three Bears." The British fairy tale follows the titular Goldilocks as she tries out the porridges of the three bears--one was too hot, the other too cold, while the third one is "just right."
One of the most notable examples of an Earth-like planet in the "Goldilocks" zone is Kepler-186f. Lying in its local habitable zone, Kepler-186f is the only planet in its system that has the potential to keep water in the liquid state. Its location at the edge of the habitable zone poses the risk of frost. However, its large size usually comes with a thicker atmosphere, offering better insulation.
