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HD 17156, HIP 13192

A faint star in northeastern Cassiopeia, Nushagak falls northeastward of the familiar 'W' shape of Cassiopeia's Chair. This is an F-type bright yellow star (or, according to some sources, a slightly cooler G-type yellow star like the Sun). Nushagak is a dwarf star, but shines more than twice as luminously as the Sun. At a distance of some 253 light years from the Solar System, however, it has a faint apparent magnitude of just +8.17, and is much too faint to be seen with the naked eye.

Imagery provided by Aladin sky atlas

Nushagak has a single known planet, a gas giant of the 'hot Jupiter' type, in a close orbit around the star. This planet, known as Mulchatna or HD 17156 b, follows a highly elliptical twenty-one-day orbit around its star, with a semi-major axis of 0.16 AU (that is, it orbits Nushagak at a distance about a fifth that of Earth from the Sun). Mulchatna is a dense planet, comparable in size to Jupiter, but more than three times as massive. (A second candidate planet in this system was also proposed at one time, but that proposal has since been retracted.)

Nushagak and its planet Mulchatna gained their names a part of the NameExoWorlds project, and are named for rivers in southwestern Alaska, with the Mulchatna being a tributary of the main river Nushagak.


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