Iota1 Scorpii
Iota1 Scorpii, Latinized from ι1 Scorpii, is a star in the southern constellation of Scorpius. With an apparent visual magnitude of 3.03, this star can be seen with the naked eye. Parallax measurements place it at a distance of roughly from Earth, with a 9% margin of error. At the estimated distance, the apparent magnitude is diminished by 0.66magnitudes due to intervening gas and dust between Earth and the star.
This star has a stellar classification of F2 Ia, with the 'Ia' luminosity class indicating this is a supergiant more luminous than typical supergiants. It has about 12 times the Sun's mass and is 35,000 times more luminous. The limb-darkened angular diameter of Iota1 Scorpii is estimated at. At the estimated distance, this corresponds to a physical radius of. The effective temperature of the photosphere is 6,910 or 7,103 K, which gives it a yellow-white hue typical of an F-type star.
Iota1 Scorpii has a 10th magnitude companion at an angular separation of 37.5 arcseconds, which, at the distance of this star, gives it a projected separation of 20,000 astronomical units. As the relative separation of the two stars along the line of sight to the Earth is not known, however, this distance represents only a minimum value for their separation.