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Re: Flashers

All my recent data measures a star only once a night.  So why not #3?  With 
three dual telescopes running, I get everything that transits the meridian 
once a night in V and I.

These are simultaneous brightenings in V and I.  Not necessarily the same 
change in V and I.

These are .2 to 1 mag increases in a star measured many times 
before.  (Otherwise the WS would not pick it up.) Sometimes I see more than 
one in the data I have for a star.  In some cases it might be shifted by 
0.001 degree.  In others it matches the other measurements to 0.0002 degree 
or better.

I have sort of assumed that these are caused by airplane trails or some 
such.  Cosmic rays cannot do it because of the simultaneous V and I 
requirement.

Tom Droege


At 11:35 PM 5/18/03 +0930, Fraser Farrell wrote:
>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
>
>----------------------------------
>http://astronomy.trilobytes.com.au
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