EXO-PLANET: 55 CANCRI E (Syllabus: GS Paper 1 – Geography)

Context: Astronomers have recently found a "super-Earth" or say an exo-planet, that orbits perilously close to a star dimmer and slightly less massive than our sun.

Rocky Planet

• Name of the planet: 55 Cancri e, also called Janssen, a so-called super-Earth, a rocky planet significantly larger than Earth but smaller than Neptune.
• About rocky planets: These planets are Earth-like planets.

o Earth, Mars, Mercury and Venus are terrestrial, or rocky, planets.

o Also known as: Terrestrial Planet.

• Finding were done after an observation of: James Webb Space Telescope.
• Atmosphere of the exo-planet: The atmosphere is likely rich in carbon dioxide or carbon monoxide, but can also have other gases such as water vapor and sulfur dioxide. The current observations cannot pinpoint the exact atmospheric composition.
• Size: 8.8 times more massive than Earth, with a diameter about twice that of our planet.
• Its star and orbit: It orbits its star at one-25th the distance between our solar system's innermost planet Mercury and the sun. 

o The planet is probably tidally locked, meaning it perpetually has the same side facing its star, much like the moon does toward Earth.

o The planet is located in our Milky Way galaxy about 41 light-years from Earth, in the constellation Cancer. 

Exo-planets:

• About: An exoplanet is any planet beyond our solar system. Most orbit other stars, but free-floating exoplanets without any star is called rogue planets.

o Almost all planets detected so far are within the Milky Way. However, there is evidence that extragalactic planets, exoplanets located in other galaxies, may exist.