54 Piscium
54 Piscium (short 54 Psc ), also known as the HD 3651, is a planetary system in the constellation Pisces. In the central body is a main sequence star of apparent magnitude 5.9 and spectral class K0. The distance of 54 Piscium to the earth is only 36 light-years and under good conditions is the star with the naked eye to detect. The central star, to distinguish it from the other bodies in the system as 54 Piscium A is often (and before the discovery of the companion objects ), but also simply as 54 Piscium, is surrounded by two sub-stellar companions to their identification usually the catalog name of the system in HD catalog use place. The central star is accompanied in a relatively short distance of an exoplanet, HD 3651 b, and at a greater distance from a brown dwarf, HD 3651 B, .
Central star
54 Piscium A ( HD 3651 A) has about 80 percent the mass of our sun and is a little less bright than this. Its metallicity is about 110 percent of the sun (relative to iron).
Brown dwarf
HD 3651 B (54 Piscium B ) is a methane dwarf of spectral type T7 to T8. The angular distance from the central star is 43 ", which projected a distance of about 480 AU corresponds. He needs for a round over 1000 years and has at least 50 times the mass of Jupiter. 54 Piscium B was et independently using the Spitzer Space Telescope ( Luhman al., 2007) and with the help of ground-based telescopes ( Murgauer et al. 2006) discovered.
Exoplanet
HD 3651 b ( 54 Piscium b, formally and to avoid confusion and HD 3651 Ab) is an exoplanet with a minimum mass of about 0.23 Jupiter masses and a sidereal orbital period of 62.206 days, of the central star of the system at a distance of approximately. 0.30 astronomical units orbiting at an eccentricity of 0.6. It was founded in 2003 by Paul Butler et al. discovered in 2003 using the radial velocity method.