9 Persei

9 Persei is a single[11] variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun.

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.

[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 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.

The Double Cluster . 9 Persei is the brightest star on right side of the image. North is to the left.
A light curve for V474 Persei. The main plot shows the variation over a year, and the inset plot shows the same data folded over the best-fit period. The data was published by Burggraaff et al. (2018) [ 13 ]