55 Cancri e, sometimes abbreviated as 55 Cnc e and formerly named "Jansen", is an extrasolar planet orbiting the Sun-like star 55 Cancri A. It is around 40 light years away from Earth. The planet is notable as it was the first super-Earth planet discovered orbiting around a main-sequence star. It was announced in October 2012 that 55 Cancri e could be a carbon planet.
Characteristics[]
55 Cancri e has a mass around 8.63 times that of Earth, and a radius of 1.875 times that of Earth, thus making it a super-Earth terrestrial planet. The planet is extremely hot - the surface temperature, on average, is around 2573 K (2,300 °C; 4,172 °F) and can reach 2,709 K (2,436 °C; 4,417 °F) at maximum. The average temperature on the night side of the planet is roughly 1,644 K (1,371 °C; 2,500 °F). Because of the extreme proximity to its star, it receives more radiation than Gliese 436 b.
The planet completes an orbit around 55 Cancri in just 17 hours. 55 Cancri e is the innermost planet of the 55 Cancri system.
The planet is almost certainly tidally locked, meaning that one side has a permanent day side and a permanent night side.
When it was first discovered, it was not known if it was a large terrestrial planet like the Earth, or if it was a small gas giant like Neptune. In 2011, a transit of the planet was confirmed and the density was calculated by scientists.
Later on, the planet was thought to be largely of diamond, and it has been speculated that the value of the planet may be $26.9 nonillion, although this theory has become less popular over the years.
In February 2016, NASA's Hubble Space Telescope detected hydrogen and helium in the atmosphere of the planet but did not find water vapor. This was the first time the atmosphere of a super-Earth was analyzed successfully. Later on, via infrared observations by the Spitzer Space Telescope, it was indicated that there may be a global ocean of lava present on the planet that is obscured by an atmosphere. The atmosphere could contain similar chemicals to Earth's, such as nitrogen and possibly oxygen, in order to cause the infrared data observed by Spitzer.
Discovery[]
Like most extrasolar planets discovered prior to the Kepler mission, 55 cancri e was discovered by detecting variations in its stars radial velocity.