八谷增廿八

八谷增廿八，即天猫座6（6 Lyncis，6 Lyn）是一个距离地球约182光年的光谱类型K型次巨星，位于天猫座。

概要

天猫座6的质量是太阳的1.7倍，半径是太阳的5.2倍，光度是太阳的15倍。视星等5.88，绝对星等2.10。

行星系统

2008年7月，该恒星旁的系外行星天猫座6b和仙女座14b、鲸鱼座81b一起被佐藤文卫宣布发现。天猫座6b的质量下限是木星的2.4倍，公转周期899日。

6 Lyncis is a star in the northern constellation of Lynx, located approximately 179 light years from Earth. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.86. This object is moving away from the Earth with a heliocentric radial velocity of +40 km/s. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.341 arc seconds per annum. One exoplanet is known to orbit it.

This is an aging giant star with a stellar classification of K0.5 IIIb Fe0.5, which indicates it has a mild overabundance of iron in its spectrum. At 2.8 billion years old, it has exhausted the hydrogen at its core, causing it to evolve away from the main sequence. As a consequence, it has expanded to 5.12 times the radius of the Sun although it only has 1.37 times the Sun's mass. The star is radiating 14.2 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,950 K.

Planetary system

In July 2008, the planet 6 Lyncis b was announced by Bun'ei Sato and collaborators from the Okayama Planet Search Program, along with 14 Andromedae b and 81 Ceti b. The planet was found to have minimum mass of 2.4 Jupiter masses and period of 899 days.