Omicron Lupi

Omicron Lupi (ο Lup) is a binary star in the southern constellation of Lupus. It is a visible to the naked eye with a combined apparent visual magnitude of 4.323. Based upon an annual parallax shift of 8.07 mas as seen from Earth, it is located around 400 light years from the Sun, give or take 30 light years. At that distance, the visual magnitude of the system is diminished by an extinction factor of due to interstellar dust. It is a member of the Upper Centaurus Lupus subgroup of the nearby Scorpius–Centaurus Association.
This is a visual binary star system with the components having an angular separation of 0.1 arc seconds. The primary, component A, is a magnitude 4.84 B-type subgiant star with a stellar classification of B5 V. It displays radial velocity variations indicating it has an unseen second companion orbiting at a separation of at least 17 AU with a period of 27 years or more. The spectrum of the primary displays a Zeeman effect indicating a magnetic field with a strength ranging from −94 to 677 G. The visible companion, component B, has a visual magnitude of 5.27.