Magnitude 7.38 Apparent magnitude (V) 7.38 | ||
Similar HD 20782 b, HD 70642, HD 102117, HD 179949, HD 12661 | ||
The planets in the binary system hd 20782 hd 20781
HD 20782 is a 7th magnitude G-type main sequence star about 117 light-years away from Earth, in the constellation of Fornax. HD 20782 is a part of a wide binary system in which the other star is designated HD 20781, and both stars host planetary systems. Indeed, this is the first known case of a binary star system where there are planetary systems around both the primary and the secondary stars in the system. The companion star HD 20781 has a very large angular separation of 252 arcsec, corresponding to 9080 AU at the distance of HD 20782. It is estimated to be 7.1 (± 4) billion years old, with a mass close to that of our Sun. (Note that, despite the numbering, HD 20782 is the primary star of the system, and HD 20781 the secondary star.)
An extremely eccentric extrasolar planet was announced around HD 20782 in 2006. In 2009 this planet's orbit was narrowed down, and it was found to have the highest eccentricity of all known exoplanets; this distinction has stood since 2012.
And in 2011 two also-eccentric (but less so) Neptune-mass planets were announced around the HD 20781.