55 Cancri d

55 Cancri d is an extrasolar planet orbiting the component 55 Cancri A of the binary system 55 Cancri. Due to its high mass is assumed that it is a gas planet. He is the fifth and outermost below the previously known planets of its system.

Discovery

As the majority of exoplanets was also discovered that using the radial velocity method. 55 Cancri d was discovered together with the planet c by Geoffrey Marcy and R. Paul Butler as the second and third planet of the system in 2002. At this time, 55 Cancri was observed for 12 years.

Web properties

The planet orbits its star at a distance of approximately 5.77 astronomical units. Since it was initially assumed that a system with three and later four -mass planet, highly eccentric orbits for 55 Cancri were d In the model with five planets as it is currently believed that eccentricity 0.025 rather small and its orbit is nearly circular. The orbital period is given as 5218 Earth days ( over 14 years). Its orbit is similar to that of Jupiter.

Physical Properties

55 Cancri d has a mass of at least 1219 earth masses and 3.835 Jupiter masses. Measurements with the Hubble Space Telescope have an inclination of the plane of the orbit of 53 ° suspect, therefore, the mass would increase to 4.8 Jupiter masses. The radius of 55 Cancri d is probably somewhat less than that of Jupiter.

There are no reliable data on the composition, size and temperature, any speculation based on model calculations. 55 Cancri d is very likely a gas planet, which should consist mainly of volatile elements like hydrogen and helium. Due to the large mass arising from the inner processes such as gas heat contraction could make so warm the planet, that it is covered with white clouds of water.

Swell

• Debra A. Fischer et al.: Five Planets Orbiting 55 Cancri. (2008) The Astrophysical Journal, 675: 790-801. doi: 10.1086/525512, arXiv: 0712.3917