57 Persei

57 Persei, or m Persei, is a suspected triple star system in the northern constellation of Perseus. It is at the lower limit of visibility to the naked eye, having a combined apparent visual magnitude of 6.08. The annual parallax shift of $−23.0$ provides a distance measure of 199 light years. 57 Persei is moving closer to the Sun with a radial velocity of about −23 km/s and will make perihelion in around 2.6 million years at a distance of roughly 6.6 pc.

The primary member, 57 Persei, is a magnitude 6.18, yellow-white hued F-type main-sequence star with a stellar classification of F0 V, indicating it is generating energy by fusing its core hydrogen. It is an estimated 1.6 billion years old and is spinning with a projected rotational velocity of 90 km/s. The star has 1.3 times the mass of the Sun and is radiating 11 times the Sun's luminosity from its photosphere at an effective temperature of around $6,615$.

An unseen companion has been identified via slight changes to the proper motion of the primary. The third possible member of the system, designated component B, is a magnitude 6.87 F-type star at an angular separation of 120.13 arc seconds. This star has a different parallax and space velocity than the primary, so it may just be a wide visual companion. There are three other nearby visual companions that are not physically associated with the 57 Persei system.