Beyond our system.
Exoplanets, which are planets that lie beyond our solar system. Thanks to NASA's Kepler telescope, thousands of exoplanets have been discovered in the past 20 years. These planets are as diverse as the planetary bodies in our own solar system.
Exoplanets range from jagged rocky planets, gas giants, and icy planets. The search for exoplanets is of particular interest for scientists to find another Earth-like body. Scientists determine whether an exoplanet has life by calculating if it’s in a habitable zone.
A potentially habitable exoplanet will have liquid water and may support life. As of March 2020, a total of 55 potentially habitable exoplanets have been found. Of those, one is believed to be Sub-terran (Mars-size), 20 Terran (Earth-size) and 34 Super Terran (Super Earths). The main feature of potentially habitable exoplanets is that they have to be located in the habitable zone of their stellar systems.
5 planets we may live on
- Gleise 832c
Gleise 832 is a red dwarf star some 16 light-years away. It has one habitable planet. Gleise 832c is actually the most similar to Earth out of all the discovered exoplanets. However, it orbits its star every 36 days. This may seem fast but Gleise 832 is a red dwarf star, much dimmer and cooler than our sun. So, Gleise 832c receives about as much stellar energy as we receive from our own sun, even though Gleise 832c orbits so much closer to its star.
- Wolf 1061c
is another red dwarf star at just 14 light-years away. Wolf 1061c is tidally locked to its star, meaning one side of the planet always faces the star. This may be problematic for life to arise on the planet since one side of the planet is very hot and one side is very cold.
- Tau Cetie
is just 12 light-years away from us and is a yellow dwarf star. However, we now know that only recently joined the habitable zone due to Tau Ceti becoming more luminous over the years. Tau Cetie F has spent only 1 billion years in its habitable zone.
- Barnard’s Star B
Six light-years away there is Barnard’s Star, a red dwarf with one habitable planet. Its mass is 3.2 times that of Earth and orbits its star every 233 days. At that distance, because the star is smaller and cooler than our sun, the planet is colder than Earth, with an estimated surface temperature of -238 degrees Fahrenheit.
- Proxima Centauri B
A planet orbiting around a red dwarf star at only 4 light-years away. Researchers don’t know for sure if the planet has an atmosphere, or whether that atmosphere could allow for liquid water to exist on Proxima B’s surface. The planet’s surface temperature is unknown because it depends heavily on atmospheric characteristics. Much research is still due, but the studies conclude that the presence of liquid water on the surface today cannot be ruled out and thus Proxima B can be considered a viable candidate habitable planet.
Source: Pennington Planetarium