Mimosa and its companion

[Brian W (Brian)]

Hi all, last night after a night of trying for faint fuzzies I swung the 8"LB to the south and prepared for some eye candy.

The Southern Cross was taking centre stage so I did some easy surfing. Open clusters with jewel like stars are always a good way to end an evening... but this time Mimosa and its companion grabbed my attention.

The carbon companion was dark blood red, darker and redder than any carbon star I have ever observed.

I am just wondering if this was just a case of atmospherics or is there something going on with this variable. Or is it just that it has been about a year since I last observed it and my memory is going as well as everything else?

[Steffen]

It's Espin-Birmingham 365, and quite a treat! Like a little red LED in the sky

Cheers
Steffen.

[ausastronomer (John Bambury)]

Hi Brian,

Steffen is correct. This star is known by a multitude of names including Espin-Birmingham 365 (EsB 365).

It is also known by DY Crucis and "Ruby Crucis", as its coloquial name. It is a variable star which varies from mag 8.4 to 9.9. It is a carbon star and like all other carbon stars, it "appears" at its "reddest", when it is at its dimmest. The period pulsates from 270 to 530 days.

Here is a link to a nice image of it

http://www.pbase.com/image/76996595

This is one of my favourite carbon stars along with R Leporus (Hind's Crimson Star)

Cheers,
John B

[ChrisM]

I concur with John's sentiment that Ruby Crucis and Hind's Crimson star are the best carbon stars (as seen from here - at least). I haven't yet attempted to measure colour or brightness, but am always taken by the stark contrast between the blue/white of Mimosa and the deep red of its (apparent) neighbour.

Cheers,
Chris

[Brian W (Brian)]

It certainly grabbed my attention. Ok now onto a question; I primarily use an 8" LightBridge for faint fuzzy hunting with a Meade 26mm QX wide angle.

It makes for easy star hopping, reasonable contrast and some real pretty colours.

Priorities being what they are a new ep is not going to be near the top of our expense list but when things change a bit any suggestions for a better ep? Pensioner on a budget type of price range if you please.
Brian