Sher 25

Sher 25 is a nearly 25,000 light -years from Earth distant star in the galactic emission nebula NGC 3603rd With an apparent magnitude of 12.23 like he is in the southern constellation keel of the boat under ideal conditions with a telescope with an aperture of at least 200 mm observed.

The mass of the blue supergiant is about 40 to 52 solar masses, at the beginning of its main sequence phase, it amounted to 60 solar masses. At this time, the star is a supergiant of spectral type B3 I. Surrounded he is of a planetary nebula, which consists of a cast-off 6560 years ago equatorial ring and a 6700 years past bipolar outflow. First described and named Sher 25 has been published by David Sher in a 1965 Monthly Notices of the Royal Astronomical Society article on the distance measurement to five open clusters.

Sher 25 is considered a candidate for a supernova of type II