Tags: Star.
For other stars with this Bayer designation see Tau Serpentis.Tau4 Serpentis (Tau4 Ser τ4 Serpentis τ4 Ser) is a M-type bright giant star in the constellation of Serpens approximately 520 light-years from the Earth. It is classified as a semiregular late-type variable star and its magnitude varies between +5.89 and +7.07 with a period of approximately 100 days. τ4 is unique among the stars with the Bayer designation τ Serpentis as being the only one with no HR catalog number.