Ζ_Sagittae
Zeta Sagittae
Star in the constellation Sagitta
Zeta Sagittae (ζ Sagittae) is triple star[3] system in the northern constellation of Sagitta. It is visible to the naked eye, having a combined apparent visual magnitude of +5.00.[2] Based upon an annual parallax shift of 12.79 mas,[1] the distance to this star is approximately 260 light years.
The inner pair is a visual binary system consisting of two A-type main-sequence stars with an orbital period of 23.2 years (8,487.9 d), a semimajor axis of 0.136 arc seconds, and an eccentricity of 0.79.[7] The primary, component A, has a visual magnitude of 5.64[3] with a stellar classification of A3 Vnn,[4] where the 'nn' suffix indicates "nebulous" lines due to rotation. It is spinning rapidly with a projected rotational velocity of 240 km/s. This is giving the star an oblate shape with an equatorial bulge that is 14% larger than the polar radius.[11]
The secondary member, component B, is a magnitude 6.04 star, while the more distant component C is magnitude 9.01 and lies at an angular separation of 8.330 arc seconds from the other two.[3]