Astronomers have made an exciting discovery in their search for habitable planets outside of our solar system. They have found a “super-Earth” called TOI-715b, which is larger than our planet and orbits a red dwarf star about 137 light-years away. This discovery was made using NASA’s Transiting Exoplanet Survey Satellite (TESS) mission and was detailed in a study published in the Monthly Notices of the Royal Astronomical Society.
TOI-715b is estimated to be one and a half times wider than Earth and takes just over 19 Earth days to complete one orbit around its star. What makes this planet even more intriguing is that it exists within the habitable zone, or the region around a star where the conditions are just right for liquid water to exist on the planet’s surface. This habitable zone is usually calculated based on various factors such as the size, temperature, and mass of the star, as well as the reflectivity of the planet’s surface. However, there can be large margins of error associated with these calculations, which raises questions about whether a planet truly resides in the habitable zone.
Lead study author Dr. Georgina Dransfield, a postdoctoral researcher at the University of Birmingham’s School of Physics and Astronomy, explains that TOI-715b is believed to exist in a narrow and more optimal region within the habitable zone known as the conservative habitable zone. This region is less likely to be affected by the margins of error associated with the calculations.
Dr. Dransfield expresses her excitement about this discovery, stating, “This discovery is exciting as it’s the first super-Earth from TESS to be found within the conservative habitable zone.” She also mentions that because this system is relatively close by, it is suitable for further atmospheric investigations.
TESS has been instrumental in helping astronomers spot planets around nearby stars that are suitable for follow-up observations. Dr. Dransfield explains that this has allowed them to gain a clearer picture of the diversity of exoplanetary systems orbiting different types of stars.
One of the reasons TOI-715b is an optimal candidate for further observations is its close proximity to its star and its quick orbit. This means that the planet frequently passes in front of its star, or transits, resulting in dips in starlight that can be detected by telescopes. The James Webb Space Telescope, which sees the universe in infrared light, will be able to observe these transits and potentially determine the planet’s atmospheric composition. This information is crucial in understanding whether planets have atmospheres and their potential habitability for life.
Dr. Dransfield emphasizes the importance of determining TOI-715b’s mass with high precision to understand if it is a true super-Earth or a member of the novel category of ocean worlds. This knowledge will shape future investigations and contribute to our understanding of exoplanet demographics as a whole.
In order to confirm the existence of a likely Earth-size second planet orbiting the same star, researchers require more successful observations of its transits in different wavelengths of light.
While TOI-715b’s star has shown a couple of flares within the past two years, it is not considered active, indicating that it is an old star. This makes it an intriguing target for further study.
Looking ahead, upcoming missions such as the European Space Agency’s PLATO mission will allow astronomers to search for planets around stars more similar to our sun. This mission, expected to launch in 2026, will carry 26 cameras to study Earth-like planets in habitable zone orbits around sun-like stars. Dr. Dransfield believes that this will be one of the most anticipated discoveries, as it will provide insight into how common planets similar to Earth really are.
The discovery of TOI-715b is a significant step forward in our understanding of exoplanets and their potential for habitability. With advancements in technology and upcoming missions, astronomers are optimistic about uncovering more Earth-like planets in the future.