Position from SIMBAD
RA, Dec (J2000) 20 01 11.915 +07 58 53.49
Michael Koppelman, 2002 September 10
Nothing in GCVS or NSV. Nothing of note in SIMBAD. Minimum
around 2452458.84. This is star 212802 in the September dataset.
It's clearly variable. Average V is 9.76 and average I is 9.34.
Amplitude could be as high as 0.8m. Seems like there may be
enough data to try to fold into a phase plot. Observations from
5 nights.
...
I agree that this seems like a great candidate for a
multi-observer campaign. As the unofficial campaign coordinator,
I'd like to urge everyone to monitor this star. It would be
great if we could get both normal ol' observers and the TASS
systems pointed at this long enough to fill in the curve. I
think it will be a very interesting curve. Please send me your
data and I will happily distribute it to whomever requests it.
As John point out, this will be interesting in color, too, so
please take filtered data. It is bright enough:
B=11.4
V=9.76
R=10.2
I=9.34
...according to TASS and USNO A2. Tycho-2 says it has "suspected
intrinsic variability". I wonder if ROTSE or any of the other
surveys have picked this one up? There are no references to it
in NASA ADS.
...
I'm thinking that HD 189797 and GSC 1071-1970 would be good if
you can fit them in the field.
B V B-V
HD 189735 9.90 9.67 0.23
HD 189797 9.60 9.37 0.23
GSC 1071-1970 10.61 10.50 0.11
HD 189662 7.90 7.50 0.40
HD 189797 is about 11.5 arc minutes away and is a perfect match.
GSC 1071-1970 is only 4 arcmin away. I'll be able to fit all of
these in my field. HD 189662 is a bright one right near by that
could work, too. Current TASS data has max=9.624 and min=10.036
so I'd be tempted to use HD 189797 and GSC 1071-1970 to sandwich
it.
Tom Droege, 2002 Sep 10
Here is the data I have so far this month for HD189735 ... Format is as in "collected" lists, but it should be obvious. Tom Droege 37275 74 300.2995 7.9815 2452521.69704 V 9.723 0.005 0 I 9.402 0.004 0 37275 74 300.2995 7.9816 2452527.60653 V 9.965 0.016 0 I 9.663 0.012 0 37275 74 300.2995 7.9816 2452522.61204 V 9.720 0.006 0 I 9.418 0.005 0 37275 74 300.2995 7.9816 2452521.65461 V 9.690 0.005 0 I 9.354 0.004 0 37275 74 300.2995 7.9815 2452521.66524 V 9.695 0.005 0 I 9.368 0.004 0 37275 74 300.2995 7.9814 2452521.67758 V 9.682 0.005 0 I 9.366 0.004 0 37275 74 300.2995 7.9816 2452526.61082 V 9.631 0.009 0 I 9.343 0.007 0 37275 74 300.2996 7.9815 2452521.68819 V 9.689 0.005 0 I 9.387 0.004 0 37275 74 300.2996 7.9816 2452521.68995 V 9.714 0.005 0 I 9.390 0.004 0 37275 74 300.2996 7.9817 2452527.59722 V 9.940 0.016 0 I 9.644 0.012 0 37275 74 300.2996 7.9816 2452527.59954 V 9.986 0.017 0 I 9.659 0.012 0 37275 74 300.2996 7.9816 2452521.69880 V 9.702 0.005 0 I 9.386 0.004 0 37275 74 300.2996 7.9816 2452521.62275 V 9.695 0.005 0 I 9.368 0.004 0 37275 74 300.2996 7.9817 2452527.60420 V 9.998 0.017 0 I 9.686 0.012 0 37275 74 300.2996 7.9815 2452524.60921 V 9.674 0.007 0 I 9.431 0.007 0 37275 74 300.2996 7.9816 2452524.61149 V 9.681 0.006 0 I 9.427 0.006 0 37275 74 300.2996 7.9815 2452521.62454 V 9.688 0.005 0 I 9.354 0.004 0 37275 74 300.2996 7.9815 2452525.60378 V 9.711 0.008 0 I 9.408 0.007 0 37275 74 300.2996 7.9815 2452525.60608 V 9.689 0.008 0 I 9.433 0.007 0 37275 74 300.2996 7.9815 2452525.60837 V 9.697 0.008 0 I 9.444 0.007 0 37275 74 300.2996 7.9815 2452525.61065 V 9.709 0.008 0 I 9.430 0.007 0 37275 74 300.2996 7.9815 2452521.61568 V 9.691 0.005 0 I 9.359 0.004 0 37275 74 300.2996 7.9816 2452521.62808 V 9.694 0.005 0 I 9.360 0.004 0 37275 74 300.2996 7.9815 2452521.62984 V 9.694 0.005 0 I 9.361 0.004 0 37275 74 300.2996 7.9815 2452522.61437 V 9.717 0.006 0 I 9.434 0.005 0 37275 74 300.2996 7.9815 2452522.61904 V 9.686 0.005 0 I 9.425 0.005 0 37275 74 300.2996 7.9816 2452521.63162 V 9.689 0.005 0 I 9.353 0.004 0 37275 74 300.2996 7.9815 2452521.63338 V 9.679 0.005 0 I 9.357 0.004 0 37275 74 300.2996 7.9816 2452521.63691 V 9.679 0.005 0 I 9.359 0.004 0 37275 74 300.2996 7.9817 2452521.63869 V 9.676 0.005 0 I 9.352 0.004 0 37275 74 300.2996 7.9816 2452521.64045 V 9.686 0.005 0 I 9.363 0.004 0 37275 74 300.2996 7.9815 2452521.61744 V 9.682 0.005 0 I 9.343 0.004 0 37275 74 300.2996 7.9816 2452521.64400 V 9.676 0.005 0 I 9.368 0.004 0 37275 74 300.2996 7.9815 2452521.64578 V 9.681 0.005 0 I 9.361 0.004 0 37275 74 300.2996 7.9815 2452521.65108 V 9.683 0.005 0 I 9.364 0.004 0 37275 74 300.2996 7.9815 2452521.65285 V 9.695 0.005 0 I 9.361 0.004 0 37275 74 300.2996 7.9816 2452526.60154 V 9.678 0.010 0 I 9.364 0.007 0 37275 74 300.2996 7.9814 2452521.65992 V 9.686 0.005 0 I 9.362 0.004 0 37275 74 300.2996 7.9815 2452521.61921 V 9.692 0.005 0 I 9.367 0.004 0 37275 74 300.2996 7.9815 2452521.66700 V 9.692 0.005 0 I 9.360 0.004 0 37275 74 300.2996 7.9816 2452526.60617 V 9.680 0.010 0 I 9.402 0.007 0 37275 74 300.2996 7.9817 2452523.60825 V 9.697 0.005 0 I 9.407 0.005 0 37275 74 300.2996 7.9815 2452521.67053 V 9.693 0.005 0 I 9.377 0.004 0 37275 74 300.2996 7.9816 2452523.61057 V 9.727 0.006 0 I 9.435 0.005 0 37275 74 300.2996 7.9816 2452521.67229 V 9.695 0.005 0 I 9.368 0.004 0 37275 74 300.2996 7.9817 2452521.67406 V 9.682 0.005 0 I 9.371 0.004 0 37275 74 300.2996 7.9815 2452521.62097 V 9.668 0.005 0 I 9.338 0.004 0 37275 74 300.2997 7.9816 2452521.68644 V 9.738 0.005 0 I 9.398 0.004 0 37275 74 300.2997 7.9816 2452521.69172 V 9.714 0.005 0 I 9.395 0.004 0 37275 74 300.2997 7.9816 2452521.69350 V 9.713 0.005 0 I 9.396 0.004 0 37275 74 300.2997 7.9817 2452521.69525 V 9.741 0.005 0 I 9.400 0.004 0 37275 74 300.2997 7.9817 2452527.60186 V 9.977 0.017 0 I 9.674 0.012 0 37275 74 300.2997 7.9816 2452524.61378 V 9.678 0.006 0 I 9.414 0.006 0 37275 74 300.2997 7.9816 2452521.62630 V 9.683 0.005 0 I 9.354 0.004 0 37275 74 300.2997 7.9817 2452521.63514 V 9.678 0.005 0 I 9.365 0.004 0 37275 74 300.2997 7.9817 2452521.64223 V 9.687 0.005 0 I 9.370 0.004 0 37275 74 300.2997 7.9817 2452521.64756 V 9.683 0.005 0 I 9.373 0.004 0 37275 74 300.2997 7.9816 2452521.64932 V 9.689 0.005 0 I 9.356 0.004 0 37275 74 300.2997 7.9816 2452521.65815 V 9.688 0.005 0 I 9.364 0.004 0 37275 74 300.2997 7.9816 2452521.66169 V 9.687 0.005 0 I 9.349 0.004 0 37275 74 300.2997 7.9816 2452526.60385 V 9.714 0.010 0 I 9.393 0.007 0 37275 74 300.2997 7.9816 2452521.66347 V 9.685 0.005 0 I 9.375 0.004 0 37275 74 300.2997 7.9816 2452523.61521 V 9.697 0.005 0 I 9.453 0.005 0 37275 74 300.2997 7.9814 2452526.60851 V 9.633 0.009 0 I 9.374 0.007 0 37275 74 300.2997 7.9816 2452521.67582 V 9.726 0.005 0 I 9.378 0.004 0 37275 74 300.2997 7.9816 2452521.67936 V 9.691 0.005 0 I 9.383 0.004 0 37275 74 300.2997 7.9815 2452521.68112 V 9.683 0.005 0 I 9.368 0.004 0 37275 74 300.2997 7.9816 2452521.68291 V 9.688 0.005 0 I 9.375 0.004 0 37275 74 300.2998 7.9815 2452521.68466 V 9.695 0.005 0 I 9.395 0.004 0 37275 74 300.2998 7.9817 2452525.61293 V 9.722 0.008 0 I 9.474 0.007 0 37275 74 300.2998 7.9816 2452522.62137 V 9.685 0.006 0 I 9.442 0.005 0 37275 74 300.2998 7.9817 2452521.65638 V 9.674 0.005 0 I 9.363 0.004 0 37275 74 300.2998 7.9816 2452521.66876 V 9.706 0.005 0 I 9.396 0.004 0 37275 74 300.2998 7.9817 2452523.61753 V 9.695 0.005 0 I 9.441 0.005 0
Michael Koppelman, 2002 September 11
I'll spare you guys the play-by-play once I get going here, but last night I showed a decline from 9.62 to 9.69 in V over the course of 4.7 hours. This one is going to take a lot of data. My data lines up pretty good with the first night of TASS data, so it wouldn't be impossible to take a stab at possible periods, although it may be a multiple of the actual period. I'm going to start compiling all of Tom's data and my data, and whatever data I get from y'all. I'll post it on my web site when I have it together. ... OK, data and a possible phase plot are linked here: http://www.lolife.com/astronomy/hd189735/ The phase plot is very sketchy. Data includes everything I've gotten from Tom and my data from last night and is HJD.
Dirk Terrell, 2002 September 11
Looks like a short-period Algol, like XZ CMi (see http://www.konkoly.hu/cgi-bin/IBVS?5310
Michael Koppelman, 2002 September 11
If my guess of a period is somewhat near correct, there is a remarkable similarity between XZ CMi and this star. My period of 0.7815 is not that far from your period of 0.578852. The amplitude is similar as well. As you point out in private email, the question is why is V-I doing what it's doing? It is not similar to XZ CMi. http://www.lolife.com/astronomy/hd189735/hd189735_phase.jpg