17 Leporis

A faint fifth-magnitude star as seen from Earth, 17 Leporis lies in the eastern parts of Lepus the Hare. In the sky, it falls approximately halfway along an imaginary line between the bright stars Sirius to the east and Arneb to the west. This is a distant star, lying some 913 light years from the Sun.

17 Leporis is a complex and active binary system, consisting of a hot white main sequence star and a red giant. These two stars follow a very close mutual orbit at a distance comparable to that of the Earth around the Sun, a cycle that takes 260 days to complete. This extreme proximity to one another means that matter from the red giant is being transferred to the white star, a phenomenon that makes this system a symbiotic binary.

This transfer of matter between the stars gives rise to sudden and unpredictable outbursts of energy, causing the system's brightness to increase at times by a fifth of a magnitude. This kind of behaviour causes the star to be classified as a 'cataclysmic' variable, and specifically a variable star of the Z Andromedae type. It is therefore assigned a variable star designation, SS Leporis. The two close stars at the heart of the binary system are surrounded by a shell of material extending out into space.