Iota_Aquarii
Iota Aquarii
B-type main sequence star in the constellation Aquarius
Iota Aquarii, Latinised from ι Aquarii, is the Bayer designation for a binary star[7] system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent magnitude of +4.279.[2] Based upon parallax measurements made during the Hipparcos mission, the distance to this star is around 175 light-years (54 parsecs).[2] The system is drifting closer to the Sun with a radial velocity of −10 km/s.[5]
The binary nature of this system was reported in 2009 following a radial velocity survey using the HARPS instrument.[4] A 2010 infrared search for companions around this star was unsuccessful.[12] The presence of a stellar companion was confirmed through direct spectral detection in 2016. The companion shows a significant velocity variation over a 77-day interval, suggesting a short orbital period.[7]
The spectrum of the primary, component A, fits a stellar classification of B8 V,[3] showing that this is a B-type main-sequence star. It is roughly 124[7] million years old and is spinning rapidly with a projected rotational velocity of 135 km/s.[10] The star has 3.2[7] times the mass of the Sun and 2.7[8] times the Sun's radius. It is radiating 74[6] times the luminosity of the Sun from its photosphere at an effective temperature of ~11,284 km/s.[8] The secondary, component B, has a spectrum of a solar-mass star.[7] The system is a source for X-ray emission.[13]