Looking Up: Swan Song For Sadr - Bless Its Heart!

Jul 2, 2018

Supergiant star Gamma Cygni lies at the center of the Northern Cross, famous asterism in the constellation Cygnus the Swan. Known by the proper name Sadr, the bright star also lies at the center of this gorgeous skyscape, featuring a complex of stars, dust clouds, and glowing nebulae along the plane of our Milky Way galaxy.
Credit Processing - Noel Carboni, Imaging - Greg Parker / nasa.gov

This week on Looking Up we cross paths with the Northern Cross, otherwise known as Cygnus the Swan, and get right to the heart of the matter.

This week I’d like to tell you about a very cool star high in the southern Colorado skies, that’s part of an even cooler constellation. The star is Sadr, which lies at the heart of Cygnus the Swan, also often called the Northern Cross. Sadr sits at the very heart of the cross. In fact, its name means “heart” in Arabic.

I love Cygnus. With the bright star Deneb as the, well, shall we say tail feather of the swan, Cygnus seems to fly down the Milky Way. Surrounding Sadr are two lovely little clusters of stars. One of these clusters, NGC 6910, makes an exquisite heart-shaped ring which is very pretty in a small telescope. Sadr appears to be in another group of stars, but is actually not part of that group, but just happens to sit in front of them, relative to Earth.

Sadr is also interesting because it is one of the most-distant stars you can see with the naked eye. At roughly 1800 ly away, Sadr is actually a big giant type of star, at least 150 times bigger than our Sun. It’s also dying, having used up its hydrogen fuel. We’re not quite sure what it will do next, so maybe grab a glass of apple Sadr and take a look at a lovely star in a lovely part of the sky. 

Explore a beautiful and complex region of nebulae strewn along the plane of our Milky Way Galaxy in this widefield skyscape.
Credit Rolf Geissinger / nasa.gov

If you’d like to take a closer look at the Sadr or any of the other wonderful and amazing things in the sky, please visit csastro.org for a link to information on our monthly meetings and our free public star parties.