Super Earth Hot Watery 55 Cancri e

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NASA’s Spitzer Space Telescope detected light emanating from a super Earth-like planet (55 Cancri e). Planet 55 Cancri e falls into a type of exoplanets designated as super-Earth planets, which are more massive than the Earth. 55 Cancri e is about twice the size of Earth and about eight times its mass. The planet orbits its parent star in approximately 18 hours, and is located beyond the solar system in the constellation of Cancer 41 light years from planet Earth.

Planet 55 Cancri e orbits a Sun-like star (55 Cancri) in the constellation of Cancer 41 light years from Earth. Star 55 Cancri is one of a few stars known to host up to five planets, being its innermost planet, 55 Cancri e. 55 Cancri e was discovered on August 30, 2004 by detecting radial velocity fluctuations as it passed in front of its parent star. There were three planets known to orbit the star at the time of this discovery. This assumption led to believe that there was a 2.8 days orbital period of the planet; however, new observations made in 2010 revealed an orbital period of 17 hours and 41 minutes.

55 Crancrie e’s orbital period suggests a distance from its hosts star equal to one twentieth that of mercury to our Sun. the planet’s orbit is tidally locked to its star, with one of its hemispheres permanently facing its star. At that distance the planet’s temperature can reach 2000 °C (3,600 °F). Initially, it was unknown whether 55 Cancri e was rocky terrestrial or a gas giant planet similar to Neptune.  A recent study made using Spitzer Space Telescope suggests that approximately one fifth of the planet’s mass may consist of light elements and compounds including water.

Using infrared imagery, Spitzer gathered data about the composition of the planet, discovering that 55 Cancri e is a desolate and hot planet, which is expected from a planet that is over 20 times as close to its star as Mercury is to the Sun. this also reinforces assumptions that 55 Cancri e might be a planet composed of water, where the precious liquid might be in a supercritical state, making liquid and gas nearly impossible to differentiate. It is believed that the density of the planet's water composition could vary from the rocky core to the outer boundaries of the planet with no clear boundary.

Scientists at the Massachusetts Institute of Technology have combined the results, discovering that the planet is 2.17 times as big as Earth with 8.57 times its mass. This finding suggest that 55 Cancri e possesses a dense rocky core surrounded by a thick layer of nearly pure water. It is estimated that the planet may be composed of 30% water compared to its mass, making 55 Cancri e the most watery exoplanet yet discovered. This places 55 Cancri e in the middle of two previous planet classifications known as super-Earths.

Taking measurements in the infrared spectrum, Spitzer was able to detect light emanating from a planet as small as a super-Earth. Measurements in the infrared are resulting as useful techniques for collecting data on fainter super-Earths whose reflection is of only 1 ppm, out of the reach of other space telescopes. Radiation in the infrared is sensitive to both the composition and temperature of the atmosphere of a planet. Spitzer was able to detect such a small planet because it was hot, and hot bodies emit more photons than cool objects.

Sponsored for another two years to conduct research on the evolution of galaxies, exoplanets and the universe, Spitzer is laying the groundwork for NASA’s James Webb Space Telescope scheduled for launch in 2018. This telescope might implement similar methods using the infrared technology to search for potentially habitable planets, which will allow a better understanding of a planet’s composition and possibly new life forms.

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