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[vsnet-campaign-ip 15] TV Col - call for observations (2-15/1/1)
Dear Southern CV observers,
TV Col is a 14th mag CV. Its orbital period is 5.5 h. The 5.2 period
is interpreted as a negative superhump. TV Col is also an intermediate
polar with a 32-m period discovered in the X-Ray.
Recently using previously published data, we discovered evidence for
another periodicity in the light curve of TV Col. The 6.4-h period would
be the longest recorded positive superhump. To confirm this period, I'll
carry out continuous photometry on TV Col during two weeks in January
(2-15) using the 0.75-m reflector with the UCT CCD in Sutherland, South
Africa.
I am calling for a campaign on TV Col during these nights. As the
candidate periodicity is relatively long, multi-longitude continuous
monitoring of the object is extremely important to reduce the aliasing
problem. So, if you can observe the object for at least ~4 h (preferably
more than one 6.4-h cycle), please let me know.
Importance of the project:
1. Break the record for longest positive superhump period.
2. The theory suggests that superhumps can occur only in CVs with small
mass ratios (q=Mdonor/Mcompact<0.33). TV Col, at 5.5 h orbital period
almost certainly has a mass ratio bigger than this limit. Therefore, a
confirmation for its positive superhump period is important to test the
models.
3. There is an argument whether superhumps can be used to estimate mass
ratios. TV Col, as the longer superhumper offers a possibility to shed
light on this problem. Naturally a radial velocity study of the
object is required as well, and indeed this is in plan.
During my vacation (14-28/12/00) I'll only have limited access to email.
I'll be leaving to SA on Saturday, 30/12/00. This is the reason for this
early email.
Some technical details:
1. coordinates (2000): 05:29:25.57 -32:49:05.19
2. Recommended filter: `clear' (no filter) - for more photons and better
signal to noise ratio.
3. Exposure times recommended: a few minutes.
4. Comparison stars - any nearby bright star. I'm planning to use the
bright star at ~1.5' SW from TV Col.
Thank you for your cooperation!
Regards,
Alon Retter
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Dr. Alon Retter Tel. (work) +44-(0)1782-58-3493
Physics Dept. Fax (work) +44-(0)1782-711093
Keele University -----------------------------------
Staffordshire 'As a scientist I don't believe myself, so
ST5 5BG, U.K. why should I believe you?' (A.R. 1965-2085)
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