51_Aquarii
51 Aquarii
Binary star system in the constellation Aquarius
61 Aquarii is a binary star[2] system located around 410[1] light years away from the Sun in the equatorial constellation of Aquarius. 51 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.78.[4] The system is moving further from the Earth with a heliocentric radial velocity of +6 km/s.[5]
The dual nature of this system was discovered by S. W. Burnham in 1873 with a 6 inches (15 cm) Alvan Clark refractor.[9] The pair orbit each other with a period of 145 years and a large eccentricity of 0.7.[6] The magnitude 6.45[2] primary, designated component A, is an A-type main sequence star with a stellar classification of A0 V.[3] It has a high rate of rotation with a projected rotational velocity of 91 km/s.[10] The secondary component has a matching class of A0 with a visual magnitude of 6.63.[2] It has an effective temperature of 10,238 K.