THE PLANETThe right-hand circle shows the location of the class F dwarf star q-1 Eridani, known as well in the Bright Star Catalogue as HR 506 and found in the deep southern end of the constellation Eridanus (as well as another planet-holding star, Iota Horologii). The star's planet, with a mass at least 0.91 times that of Jupiter, orbits with a period of 1040 days, or 2.85 years at an average distance of 2.10 Astronomical Units (315 million kilometers, 196 million miles), or 38 percent greater than the size of Mars's path around the Sun. A modest orbital eccentricity takes the planet from as far as 2.48 AU from its parent star to 1.72 AU. |