[Aavso-photometry] extrasolar planet photometry

[Richard Huziak]

Let me answer this philosphically.  I suspect the data will be used to 
refine the orbital period of the planet and look for any long-term 
changes in a similar way to what the EB group looks for in their binary 
photometry, though mass-loss/period change/precession detections are 
unlikely in the short term, but who knows.  What would be even cooler 
would be a small blip occurring in the curve as we wait for the main 
eclipse to happen - though hoping to discover a second planet by this 
method is really dreamland.  I think our value will be in initial 
discovery of potential objects and their follow-on parametric 
determination.  At any rate, you get a really cool flock of butterflies 
in your stomach when you've detected an exo-planet transit even if it 
has been seen before.  Certainly pulling useful data out of a 0.02 mag 
deep  eclipse/transit helps us hone our styles too.

I will, with this, add Gord Sarty's (SGE) and my (HUZ) observation of 
HD209458 on Jul 17/18/04 to the list of those who have reported their 
positive detections.

http://prana.usask.ca/~sarty/PhotometryGroup/   (scroll to the bottom of 
the page)

Some of you (including yourself) will remember how giddy I was when I 
showed this data to you at the Berkeley conference only a few days after 
we did the run, and had a chance to show it to Tony Castellano & Arto 
Oksanan personally.   As many have said, getting good data on such a 
bright star is difficult, and especially so when you are as 
inexperienced as we were (which I know you are not).  The two graphs 
show the 579 raw points (sans error bars), then the 10 point average. 
 The ingress was spoiled by bright sky and major extinction (ie: ingress 
not detected), but the egress shows up well, as the points jump up 
consistently about 0.02 mag near the end of the run.  We shot in V, 
though we had prepared B flats as well.  Exposure time per frame was 
only 8 seconds (on a 12" scope).  In the future, to correct the 
problems, we'll simply stop the scope down to 3.5" with an off-axis 
mask, and improve the data.  We haven't submitted the data to the AAVSO 
yet.  We are waiting for Arne's calibrated field and the thousandth mag 
database change and we will reanalyse the data thereafter. :-)  I'm also 
looking forward to our window on TReS-1 which is coming up in a few week 
or so, and will take Brian's suggestion to run on the other HD 7.6 mag 
star possible transit (again by stopping the aperture down).

Rick

Michael Koppelman wrote:

> I'm wondering where the science is in this extrasolar planet 
> photometry stuff. Are we interested in times of minima? Times of 
> ingress and egress? Is it just a photometric challenge to test our 
> skills? Are we looking for period changes, color changes, etc?
>
> I'm just curious what our data will be used for in regards to the 
> study of these sorts of (already discovered) planets.
>
> Cheers,
> Michael Koppelman
> http://www.lolife.com/astronomy/
>
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Richard Huziak
Manufacturing Engineering
SED Systems, Saskatoon
tel. (306) 933-1676
<huziak at SEDSystems.ca>
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