La Superba

October 04, 2016

La_Superba_EPOD (2)

Photographer: Greg Parker
Summary Author: Greg Parker

Shown above at center is La Superba as observed from the New Forest Observatory in England. This carbon star was given its popular name by the 19th-century spectroscopist Angelo Secchi who was impressed by its ruby-like appearance in the sky and its very unusual spectrum. Like all carbon stars, La Superba, or Y Canum Venaticorum, is a variable star with a cycle of around 160 days. It lies in the constellation Canes Venatici (the Hunting Dogs). La Superba's magnitude varies between +4.86 and +7.32 -- at +4.86 it's visible to the naked eye, away from city lights. It's not only one of the reddest stars in the sky (see the July 6, 2014, EPOD), it's also among the brightest of the carbon stars. In fact, it's the brightest J-class star in the sky, a class of carbon star that contains large amounts of carbon-13.

What I've noticed in imaging carbon stars (rubies), is that there's nearly always a close-by, bright blue star (sapphire) to provide a striking color contrast. In this case, the bright blue companion star is SAO 44292 (HIP 61989) at magnitude 7.01 -- not visible to the naked eye.

Photo Details: Image was taken on August 27, 2016, using the Sky 90 array at the New Forest Observatory with 10-Megapixel M26C OSC CCDs. A total exposure time of around two hours, using 10-minute subs went into this image.