Re: Flashers

[Fraser Farrell <fraser@trilobytes.com.au>]

Tom Droege wrote:
> Are there many stars that flash?  I keep finding stars with one bright
> point. 


TASS Press Release : the Mark IV discovers gravitational lens events....  :-)


Three of the four astronomical possibilities that come to mind can all be 
dismissed:

 - Pulsars. Not bright enough (optically), and they would flash many many 
times during a single Mark IV exposure.

 - Gamma ray burst's optical counterpart. This might explain those occasional 
"seen once and never again" stars.

 - Dwarf novae outbursts typically go on for hours, sometimes days. Lots of 
these potentially detectable by TASS. But if you're taking many images per 
night of a dwarf nova, you would see it "bright" on several consecutive 
images.

The fourth possibility is red dwarfs that are Flare Stars. These are 
detectable as occasional outbursts of light & radio waves that last 10-30 
minutes. Proxima Centauri, for example, can brighten from its usual mag 11 up 
to mag 9 during a flare. Quite a sight if you're lucky enough to see one!


cheers,


-- 

Fraser Farrell

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