Rho Ophiuchi (5 Ophiuchi) -- Multiple Star in Ophiuchus
Rho Ophiuchi -- A Blue Starred System
Rho Ophiuchi, also known as 5–Ophiuchi, is a five-star system of which four of the stars are
easily seen in amateur telescopes. All four of the visible stars are light blue in color (Spectral
Type B). The brightest sun in the star system and its optically close companion (3.1 arcseconds
apart) are both Blue Subgiants which take 2,400 years to orbit around each other. The fifth (not
visible) star Rho Ophiuchi "E" is a close companion to Rho Ophiuchi “D” and has an orbital
period of 680 years around Rho Ophiuchi “D”.
This pleasing multi-star system is easy to locate just 3 degrees due north of Messier 4, the great
Globular Cluster, which itself is just one-degree west of Antares (the heart of the scorpion). The
Rho Ophiuchi star system is embedded in the expansive Rho Ophiuchi Nebula (IC 4604), a
spectacular emission nebula in photographs.