Ι_Sagittarii
Iota Sagittarii
Astrometric binary star in the constellation Sagittarius
Iota Sagittarii (Iota Sgr, ι Sagittarii, ι Sgr) is a star in the zodiac constellation of Sagittarius. With an apparent visual magnitude of +4.118, it is bright enough to be viewed with the naked eye.[2] Based upon an annual parallax shift of 17.94 mas as seen from Earth,[1] this star is located 182 light years from the Sun. It is moving away from the Earth with a radial velocity of +35.8 km/s.[3]
This is a probable astrometric binary,[8] based upon proper motion data collected during the Hipparcos mission.[9] The visible component shows the spectrum of an evolved K-type giant or bright giant star with a stellar classification of K0 II-III.[3] The measured angular diameter, after correction for limb darkening, is 2.32±0.02 mas.[10] At an estimated distance of this star, this yields a physical size of about 14 times the radius of the Sun.[5] It has 1.4[3] times the mass of the Sun and is radiating 87[3] times the Sun's luminosity from its photosphere at an effective temperature of about 4,594 K.[3]