Do stars rotate, or revolve?
Stars rotate on its own axis. The sun rotates on its axis every 30 days on average. Sirius on the other hand rotates on its axis at a moderately slow speed of 16km/sec. With a radius of roughly 1.75x that of the sun, it makes a complete rotation in under 5.5 days. Stars revolve around a common center of gravity IF they happen to be in a multiple star system. Sirius is a member of a binary with a massive white dwarf, which I think you know is Sirius B. They revolve a common center of gravity of 20AU on average (8AU at perigee and 31.5AU at apogee) at around 50.1 years. Anyway, all stars in a galaxy still have their galactic orbits that takes hundreds of millions of years. For useful links, I pasted them below: http://www.astro.uiuc.edu/~kaler/sow/sir… http://www.astro.uiuc.edu/~kaler/sow/sow…
