UV Aurigae

Jack Kramer

Here's one of those stellar systems that's interesting to search out - UV Aurigae is both a variable and double star. The primary component is an orange-colored carbon star whose magnitude varies on about a one-year cycle. The brightest it gets is around magnitude 7.4. The secondary is a blue giant of magnitude 11.5. Carbon stars are the coolest of the stars, glowing a deep orange color. They get the name from the fact that light is filtered through the element carbon in their outer atmospheres.

UV is shown in the lower left of the above chart from the Guide computer program. Finding it will take a bit of effort because it's not particularly bright. You'll need a decent finder for star hopping. Start by locating an asterism in Auriga called the "Leaping Minnow". Located about 4o east of the star 3 Aurigae, it's composed of the stars 14, 16, 17, 18 and 19 Aurigae. Although it's in an area full of open clusters, the Minnow is not itself a true cluster - just a chance juxtaposition of stars seen as a slightly arched line that might suggest a fish jumping out of water. I first noticed this asterism many years ago while wandering the sky with a copy lens telescope. It's also an easy target for binoculars.

I located UV with a 4-inch refractor, but was unable to identify the secondary. Also, it didn't appear particularly reddish, but that's understandable because you need more light gathering ability to clearly see colors in faint stars. With my 6-inch refractor, the color was more apparent, both in the primary and secondary stars. Larger scopes will provide a more dramatic view, though UV is a poor competitor to brighter double stars.