El 8/7/2015, a las 16:08, Joe Patterson <jop@xxxxxxxxxxxxxxxxxx>
escribió:
Hi Donn et al.,
Thanx for the details. Yes, I think it is a "super-period" around
12 hours or so... but the precise value will depend on filter
issues (since the AM Her stars often show really bright I emission
due to cyclotron emission). The basic period seems to be 81
minutes, a very plausible Porb - but the star is pretty remarkable
for its super-period, and for its huge variations on a timescale of
just a few seconds (or maybe even less than 1 sec!).
As Enrique says, we'll be able to splice these light curves
together better when the star transits closer to local midnight.
Shawn
(easternmost USA observer) and Josch/Arto (Chile observers) will be
in a good position to splice with Spanish observers (Enrique,
David, Tomas). And Gordon (AU) may be able to splice with Berto (ZA).
joe
On 7/8/2015 9:41 AM, Donn Starkey wrote:
Joe, et.al.:
My runs on IGR J19552+0044 were performed using a clear filter. The
comp star was AAVSO 145 and the K star was AAVSO 148. I used the R
magnitude for these two stars:
C star AAVSO 145 R mag 14.258
K star AAVSO 148 R mag 14.292
Exposure times were at 120 sec for each night of observation.
Because of the placement of this star [or maybe because of my
placement
in relationship to the star] I started observing a very high air
masses. Originally, I had thought that the star was brightening
during
the run due to lowering air masses, but subsequent runs shows that
the data did not appear to be effected by the air mass. Is this a
long
term period fluctuation on the order of a multiple of ~12 hours?
I am out of town until the 17th, but will continue observations on
this
target when I return home....unless directed otherwise.
Donn
----------------------------------------
Donn Starkey
donn@xxxxxxxxxx <mailto:donn@xxxxxxxxxx>
------------------------------------------------------------------------
*From:* Joe Patterson <jop@xxxxxxxxxxxxxxxxxx>
*To:* Gordon Myers <gordonmyers@xxxxxxxxxxx>; Enrique de Miguel
<edmiguel63@xxxxxxxxx>; donn@xxxxxxxxxx
*Sent:* Monday, July 6, 2015 11:06 PM
*Subject:* IGR J19552+0044
Hi guys,
Helluva entertaining star this is! The 81 minute period is very
obvious, of course, and so are the super-fast (<5 s actually)
oscillations in the "high state". But I'm having trouble
putting these
time-series on a common scale. Because of the star's equatorial
location, it's hard to get overlap - and we don't have any strict
overlap. In addition, there's some reason to believe that the
brightness of the star is very different in V versus R versus
I. (Not
known, but very possible.)
So can you state in detail how you derived your magnitudes
(even if you
did in your original submission), and then copy all of us on
it? I
sure
would like to figure out that longish period or quasi-period
that seems
to be present (around a day?).
As you know, most CVs look pretty much the same at any
wavelengths near
BVRI (their colors are usually close to B=V=R=I=0). But the
magnetics
(AM Hers) are often much brighter in I, because of cyclotron
radiation.
You could perhaps check this by taking some data in I.
joe
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