[BAA 00257] Did you photograph the "W" of Cassiope

[Rick]

BAA electronic bulletin No. 00257

There has been an interesting event recently as detailed below. Please advise the VSS Director if you have any images and where possible email them to me at rdp at astronomy dot freeserve dot co cot uk. I can supply a finder chart of the area in question.

Many thanks to Tom Krajci for instigating this initiative.

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From: "Tom Krajci"
Sent: Monday, November 13, 2006 2:49 PM

Did you photograph the "W" of Cassiopeia in October? If so, you may be sitting on a gold mine and not even know it!

A star (GSC 3656-1328, at 00 09 22 +54 39 44 (2000)) recently brightened from approx. magnitude 11.5 to as bright as magnitude 7.5 on Halloween night! (This is in the western end of the "W" of Cassiopeia.)

Since it's discovery in late October the star has been intensely studied by amateurs, professionals, and observing time of orbiting telescopes has even been allocated to observe this object! We have very little coverage of this object before discovery, so any image taken of this field in October can tell us a great deal about how this star behaved before the start of
intense coverage.

If you photographed this field at any time in the month of October, your image has scientific value! It can be an image taken with film, digital SLR, CCD...anything. Even a wide field shot taken with a short focal length lens can reach deep enough to show the presence or absence of a star of the brightness we're talking about.

Why all the fuss about one star? It appears to be a very unusual event: possibly a gravitational microlensing event. (Spectra of the star don't show the typical signs of an exploding/outbursting star, and the light curve from late October to mid-November appear to fit what one would expect for a microlensing event. But more data is needed to provide the best possible analysis and conclusion about this event.)

Thanks in advance.

Tom Krajci

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Roger Pickard, Director BAA VSS

[Rick]

This event got a mention at the BAA meeting last Saturday. It seems there's quite a lot of interest in filling in gaps in the light curve of the event because it was so unusual. Incidentally, it also draws attention to the importance of recording exactly when an image is taken.