Free Astronomy Magazine May-June 2016

10 MAY-JUNE 2016 PLANETOLOGY of 55 Cancri e is very short, about 18 hours, which im- plies that the visi- ble ‘surface’ of the planet is character- ized by very high tem- peratures, even up to 2,000 degrees C. In a scenario such as this, if the ‘blazing-hot’ planet has an atmosphere suffi- ciently dense and transits on the disk of its host star, there is the possibility to sepa- rate the stellar spectrum from the planetary atmosphere, in being also this rather intense. This is the case of 55 Cancri e, that be- sides transiting on the stellar disk it is also surrounded by a dense gaseous envelope, which has been recently inves- tigated by an international team led by researchers of the University College Lon- don. By processing with new analytical tech- niques the data collected on the 55 Cancri system by the Hubble Space Telescope, the researchers found that planet ‘e’, whose mass is more than 8 times that of the Earth, T hanks to the consistency and high tempera- ture of 55 Cancri e’s atmosphere, researchers were able to chemically analyze it during the transit on the stellar disk, after isolating its spec- trum from that of 55 Cancri. Below, schematic il- lustration of the internal structure of the planet, which according to some researchers may have a thick layer formed of pure carbon, i.e. dia- monds. [NASA, Haven Giguere/Yale University] (‘e’ indicates that it was the fourth planet discovered in that system), rotates as easy to guess around the star 55 Cancri, a star sim- ilar to the Sun, located just 40 light-years away from Earth. The revolution period I n the back- ground, a re- presentation of 55 Cancri e, the first super-Earth to have its atmo- sphere analyzed. The surface tem- perature is about 2000 degrees C. [ESA/Hubble/ M. Kornmesser]