The Transiting Exoplanet Survey Satellite (TESS) of the National Aeronautics and Space Administration (NASA) has recently discovered a new planetary system, named TESS Object of Interest (TOI) 270. Located 73 light years away from Earth, within the constellation Pictor, this newly found system provides an exciting opportunity to understand the formation and evolution of planetary systems.
Overview of TOI 270
TOI 270 is a system composed of a dwarf star and three exoplanets. The dwarf star, also designated as TOI 270, is approximately 40% smaller than our sun in terms of size and mass. The constellation Pictor, where TOI 270 resides, occupies a region in the southern celestial hemisphere. This newfound system provides a unique study material for astronomers due to its closeness compared to other exoplanets, and its compactness.
The Specifics of the Three Exoplanets
The system of TOI 270 includes three exoplanets, each differing in size, orbit and nature. Labeled as TOI 270 b, c, and d, these planets have distinct characteristics that set them apart from each other and those found in our solar system.
TOI 270 b is the system’s innermost planet, being roughly 25% larger than Earth and having a mass approximately 1.9 times greater than that of Earth. Its orbit takes 3.4 days and lies closer to its host star than Mercury is to our Sun, making it oven-hot and hence, not habitable.
Exoplanets TOI 270 c and TOI 270 d, however, are gas-dominated planets resembling Neptune in our solar system. They are categorised as ‘mini-Neptunes,’ a type of planet that is absent in our solar system. TOI 270 c is 2.4 times the size of Earth, has roughly seven times the mass of Earth, and completes an orbit every 5.7 days. Conversely, TOI 270 d is 2.1 times the size of Earth, approximately five times heavier and takes 11.4 days to complete an orbit around the dwarf star.
Tidal Locking in TOI 270 System
All planets within the TOI 270 system are believed to be tidally locked to their star. This means the period of the planets’ rotation on their axes equals their period of revolution around the dwarf star, implying that the same side always faces the star, an action mirroring how the Moon orbits around the Earth.
| Planet | Size (times larger than Earth) | Orbital Period (days) | Mass (times the mass of Earth) |
|---|---|---|---|
| TOI 270 b | 1.25 | 3.4 | 1.9 |
| TOI 270 c | 2.4 | 5.7 | 7 |
| TOI 270 d | 2.1 | 11.4 | 5 |
Implications for Planetary Understanding
The compactness of the TOI 270 system presents a unique opportunity to enhance our understanding of planetary systems. With closer orbital distances not unlike Jupiter and its moons in our own solar system, TOI 270 can provide critical insights into the formation and evolution of different types of planets and their system dynamics.
