Deepsky Top-100 (11): Y cnv (La Superba)

In Canes Venatici, the hunting dogs, you can find a beautiful red star, Y Canum Venaticorum, or "La Superba". Y CVn is a carbon star. Most of these class C stars are evolved cooling giants with a large abundance of carbon dust in their outer shells. The apparent red color of carbon stars is caused by the carbon molecules (Carbon Monoxyide, Cyanogen, etc) in the outside layers of the star. These molecules create an absorption spectrum, cutting out the blue and violet light, giving the star it's red color. The name " La Superba" was given to Y CVn by Father Angelo Secchi (a 19th century star classifier) because of the beauty of its spectrum.

La Superba, is a variable star, with a period of 160 days. It's magnitude varies from 4.8 to 6.4. When the star reaches it's maximum of 4.8 you might just be able to detect it with your naked eye. According to James Kaler, Y CVn is one of the coolest naked eye stars, with a temperature of 2200 Kelvin. If you cannot detect using your naked eyes, don't worry. La Superba is easy to locate. Start at 12 Alpha Canum Venaticorum, also knows as Cor Caroli, a double star of magnitude 2.89. From there go about 6 degrees northwest to chara (8 beta CVn), a star of the 4th magnitude. From Chara go 5 degrees in north-northwestern direction where you will find La Superba.

Click here to download a printable finder chart (PDF)


The sketch below should give you an idea of the starfield around La Superba. It was made using my 8-inch f/10 Klevtzov-Cassegrain and a 20 mm vixen Lanthanum eyepiece. Magnification is 100x and the true field of view is 28'. Limiting magnitude is 12. North is up and west is to the left.