Ν2_Sagittarii
Nu2 Sagittarii
Star in the constellation Sagittarius
Nu2 Sagittarii (ν2 Sagittarii) is a binary star[8] system in the zodiac constellation of Sagittarius. It is faintly visible to the naked eye, having an apparent visual magnitude of +4.98;[2] it is 0.16 degree north of the ecliptic. The annual parallax shift of 11.91 mas as seen from Earth,[1] indicates this system is roughly 270 light years from the Sun. Nu2 Sagittarii has a high peculiar velocity of 86.0+11.6
−14.4 km/s and is most likely a runaway star system.[3]
The spectrum of the primary component displays a stellar classification of K1 Ib–II,[3] indicating this is a K-type star with a mixed luminosity class of an evolved bright giant/supergiant star. It is a mild barium star, showing an enhanced abundance of s-process elements in its outer atmosphere. This material was most likely acquired during a previous mass transfer from its now white dwarf companion.[9] The primary has an estimated 1.4[2] times the mass of the Sun and has expanded to 85[5] times the Sun's radius.