107 Piscium

The Star

107 Piscium is a orange-red main sequence dwarf star of spectral and luminosity type K1 V. The star has about 89 percent of Sol's mass, 80 to 86 percent of its diameter (Perrin and Karoji, 1987, page 236; and Johnson and Wright, 1983, page 649), and about 37 percent of its luminosity . It appears to be about 63 percent as enriched as Sol with elements heavier than hydrogen ("metallicity"), based on its abundance of iron (Cayrel de Strobel et al, 1991, page 278). 107 Piscium has the New Suspected Variable designation NSV 600 and possibly two optical companions. Useful star catalogue numbers for 107 Piscium include: 107 Psc, HR 493, Gl 68, Hip 7981, HD 10476, BD+19 279, SAO 74883, LHS 1287, LTT 10596, and LFT 153.

Hunt for Substellar Companions

The failure, thus far, to find large substellar objects like brown dwarfs or a Jupiter- or Saturn-class planet in a "torch" orbit (closer han the Mercury to Sun distance) around 107 Piscium -- with even the highly sensitive radial-velocity technique of Geoffrey W. Marcy and R. Paul Butler -- bodes well for the possibility of Earth-type terrestrial planets around this star (Cumming et al, 1999). Indeed, the distance from 107 Piscium where an Earth-type planet would be "comfortable" with liquid water is centered around only 0.62 AU -- between the orbital distances of Mercury and Venus in the Solar System. At that distance from the star, such a planet would have an orbital period of about 202 days -- less than two thirds of an Earth year. Astronomers would find it very difficult to detect using present methods.