Sadalmelik

Alpha Aquarii (α Aquarii, abbreviated Alpha Aqr, α Aqr), officially named Sadalmelik /ˌsædəlˈmɛlɪk/, is a single star in the constellation of Aquarius. The apparent visual magnitude of 2.94 makes this the second-brightest star in Aquarius. Based upon parallax measurements made during the Hipparcos mission, it is located at a distance of roughly 520 light-years (160 parsecs) from the Sun.

With an age of 53 million years, Alpha Aquarii has evolved into a supergiant with a stellar classification of G2 Ib. It has 5.1 times as much mass as the Sun and has expanded to around 56 times the Sun's radius. It is radiating 2,100 times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 5,383 K. At this heat, the star glows with the yellow hue of a G-type star. Examination of this star with the Chandra X-ray Observatory shows it to be significantly X-ray deficient compared to G-type main sequence stars. This deficit is a common feature of early G-type giant stars.

The visual companion (UCAC2 31789179) has an apparent visual magnitude of approximately 12.2. It is at an angular separation of 110.4 arcseconds from Alpha Aquarii along a position angle of 40°.