Graphics related to detection of Neptune-Mass planets

Detection of a Neptune-Mass Planet orbiting GJ 436 Graphic of the Neptune-Mass companion to GJ 436 Radial Velocity data for GJ 436 from Keck Observatory Keck Observatory

Detection of a Neptune-Mass Planet orbiting 55 Cancri Movie of 55 Cnc System

The Hobby-Eberly Telescope at McDonald Observatory HET Radial Velocity data for the Neptune-Mass planet orbiting 55 Cnc Lick Observatory Artistic rendition of the Inner planet in the 55 Cnc system by Lynette Cook Lynette Cook graphic of the Inner 3 planets orbiting 55 Cnc Comparison of the relative sizes of Neptune-Mass planets This illustration compares the size of the newfound Neptune-sized planets beyond our solar system to that of Earth and Jupiter. The new planets are only about 20 times the mass of Earth, or about two times the actual size or diameter - much smaller than the majority of Jupiter-sized extrasolar planets detected so far. Astronomers do not know if these planets are rocky, like Earth, or gaseous, like Jupiter. Rocky planets are smaller in diameter than gaseous ones of the same mass.