9_Persei
9 Persei
Blue supergiant star in the constellation Perseus
9 Persei is a single[11] variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; 9 Persei is the Flamsteed designation. This body is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of about 5.2. It is moving closer to the Sun with a heliocentric radial velocity of −15.2 km/s.[5] The star is a member of the Perseus OB1 association of co-moving stars.[12]
This is a blue supergiant with a stellar classification of A2 Ia,[3] a massive star that has used up its core hydrogen and is now fusing heavier elements. It is an Alpha Cygni variable (designated V474 Persei), a type of non-radial pulsating variable. It ranges in magnitude from 5.15 down to 5.25.[14] The star has 10.5[7] times the mass of the Sun and has expanded to 89[1] times the Sun's radius. It is radiating over 12,000[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 9,840 K.[9]
9 Persei has one visual companion, designated component B, at an angular separation of 12.3″ and magnitude 12.0.[15]