Alpha Cancri is a star system in the northern constellation of Cancer. Its name is a Bayer designation that is Latinized from ñ Cancri, and abbreviated Alpha Cnc or ñ Cnc. The primary component has the proper name Acubens, pronounced . It forms a fourth-magnitude star with an apparent magnitude of 4.20, making it visible to the naked eye under good viewing conditions. Based on parallax measurements, it is located at a distance of from the Sun, but is drifting closer with a radial velocity of âÂÂ12 km/s. Since it is near the ecliptic, it can be occulted by the Moon.
The primary component, ñ Cancri A, has a stellar classification of kA7VmF0/2III/IVSr, indicating an Am star with calcium K-lines similar to an A7 main sequence star and hydrogen lines more like an F0 giant or subgiant star. It is a white A-type main-sequence star with an apparent magnitude of +4.26. The star has 2.10 times the mass of the Sun and 3.7 times the Sun's radius. It has a high rate of spin, showing a projected rotational velocity of 75 km/s. The star is radiating 49 times the luminosity of the Sun from its photosphere at an effective temperature of 7,943 K.
Its companion, ñ Cancri B, is an eleventh-magnitude star. In the year 1836, its position angle was observed at 325 degrees with a separation from the main star ñ Cancri A of 11.3 arcseconds. ñ Cancri A may itself be a close binary, consisting of two stars with similar brightness and a separation of 0.1 arcsecond, though this is questioned. Indeed, a light curve generated during a 2014 lunar occultation failed to demonstrate a close companion.
ñ Cancri (Latinised to Alpha Cancri) is the star's Bayer designation.
Johann Bode designated this star as ñ<sup>2</sup> Cancri, as he also used the superscript ñ<sup>1</sup> for the star 60 Cancri. Bode's superscripts are rarely used though, so the designations have reverted ever since.
The traditional name Acubens (Açubens) is derived from the Arabic , 'the claws'. A second name, Sertan , derives from the Arabic al-saraá¹ÂÃÂn, 'the crab'. These names were traditionally shared with ù Cancri, which marks the crab's other claw. The International Astronomical Union's Working Group on Star Names (WGSN) chose Acubens as the proper name for the primary component ñ Cancri A.
USS Acubens (AKS-5) was a United States Navy ship.