From jop at astro.columbia.edu Sat Mar 1 11:59:34 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 1 Mar 2003 11:59:34 -0500 (EST) Subject: (cba:news) I take it all back... Message-ID: Well, maybe I spoke too soon. I spent a few hours studying the results on UMa7 and EC1056-29. We only have ~5 nights for each star, and most of the runs are fairly short (<4 hours). But in both stars there's some evidence of periodic signals near 3 hours. The evidence is assuredly weak, but since both stars don't go in much for flickering, the sensitivity of the period search will grow and grow as the baseline improves. We've done very well on period searches in such stars - the likely "VY Scl" and/or "SW Sex" stars. Soooooo... I think I called off the dogs too soon. Let 'em loose! Both stars transit near local midnight and have friendly declinations. Plus the southern star is slightly accessible for USA longitudes, which enables (in principle) nearly continuous coverage. If we can accumulate some *densely* spaced (long, and overlapping) observations spanning about a week, we can nail these babies down. Hence let's revise that list: NORTHERN - priority: UMa7, HQ Mon other: FS Aur, DW Cnc SOUTHERN - priority: HQ Mon, EC1056-2902 other: EC11588-3142 joe From jop at astro.columbia.edu Fri Mar 7 07:23:33 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 7 Mar 2003 07:23:33 -0500 (EST) Subject: (cba:news) Re: UMa 7 - long photometry session ongoing at CBA Belgium Observatory / follow-up needed In-Reply-To: Message-ID: Just wanted to echo Tonny's entreaty! UMa7 and HQ Mon are both somewhat tough nuts to crack, but it seems likely we'll find those periods if we can get the long coverage around the globe. The USA reports have been sparse lately... but this is a valuable window, before Smilin' Tom tells us to go to the duct tape again. By the way, CBA-Pahala (Hawaii, Lew Cook) and CBA-Uzbekistan (Tashkent, Tom Krajci) are now producing some excellent data sets. This really helps to fix our greatest weakness for many years, the Asia-Pacific gap. joe From jop at astro.columbia.edu Sun Mar 9 14:05:36 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 9 Mar 2003 14:05:36 -0500 (EST) Subject: (cba:news) Stars of the Equinox Message-ID: Dear CBAers, Orion still rides high in the evening sky, the snow is still on the ground, and Olde Whiteface is gearing up for yet another assault on the night.... But the temperature threatened 50 yesterday, the PGA moved back East, George Steinbrenner has failed to destroy baseball for yet another week, and spring break is a week away! So things are lookin' up. Time for a major overhaul of CBA targets. Both UMa7 and HQ Mon have yielded some fairly disappointing light curves, not things you want to show your mom. But a power spectrum indicates that UMa7 is actually delivering the goods, showing multiple periods. Part of the reason for the ugly light curves is the beating of incommensurate frequencies with similar amplitudes. This is the work of Tonny, David Messier, Jerry Foote, and Brian Martin. Tonny will announce the result when he's ready... but for now the important thing is to vault UMa7 up there as the top target for northern observers. With that lovely location (1004+66) and adequately bright (about 15.2), it should survive the onslaught of moonlight pretty well. 10 04 34.69 +66 29 14.6 (2000), for the record. The best comp appears to be GSC 4143:823, if it's convenient to get it on the chip. We can live with other comps, though, if you document things pretty well. HQ Mon is different. Not yet suitable for either your mom *or* the astronomical journals (whose standards are obviously lower). Lew Cook, Robert Rea, and Tom Krajci have been pounding away on it. But with HQ's equatorial location and (slightly) unfavorable season, the individual runs have been not as long as we'd like, and the star's period turns out to be near 8 hours - a tough one for us! Plus the star waffles around with a ~0.5 mag variation on a timescale of a few days, which seems to disturb the amplitude of the faster signal. Very tough. Just for the (informal) record, the photometric signal is likely to be at 7.59+-0.08 hours - but I'd hate to have to prove it! So we'll RETIRE HQ Mon until a future observing season. So the Q-Mon boys, HQ and KQ, have survived CBA attack for yet another year. The prime SOUTHERN target should now be EC11588-3142 ("Hya" in the CV Catalogue). The first looks by Lew and Bob Rea (and Berto) are exceptionally promising. It's bright enough (13) to survive moonlight and well placed in the sky. We need LONG runs to decipher its timescales of variation. First indication is something like (~15 minute flickering, ~4 hr signal, maybe ~4 day signal)... kind of CBA blue-plate special for a long campaign. I hope that observers in the southern USA will consider this one too - even a 2-hour run might bridge the gap between the southern observers and thereby give us our round-the-world calibration (we still have no one in South America). 12 01 24.35 -31 59 26.8 (2000) for the record. GSC 7235:1420 and 7235:1435 are both very acceptable comps. So those are the big ones. Here are the others: SOUTHERN. T Pyx: we need one more set of orbital light curves (about a week's worth). That'll nail down the orbital phase to high precision until next year. (Unless it erupts, of course.) WX Cen. A probable supersoft, quite bright and crying out for another CBA campaign. NORTHERN. EC11588-3142: well, I hope you can do it. However, I hear you can't get blood from a turnip. V405 Aur and PQ Gem: DQ Her stars in need of late-season pulse timings. Perfect for a few hours in the evening. FS Aur: a mystery star, out of season but we're trying to phase up its strange 3.5 hour variation over the past 5 years. Off-season timings are of particular value in that enterprise - but they do have to be ~3 hrs long. Well, that's the menu. See what tasty things you can find in it! joe From jop at astro.columbia.edu Mon Mar 24 19:00:46 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 24 Mar 2003 19:00:46 -0500 (EST) Subject: (cba:news) new season, new stars Message-ID: Dear CBAers, Just finished analyzing a mess of data on Feb-March campaign stars. Will write of the results tomorrow. For now, I'd like to shuffle priorities for the new dark-moon period... The following stars are done for the season: T Pyx, UMa7, and EC1158-3142. Details to follow... Here are the new targets I recommend: NORTH. UMa6. Top priority, available most of the night. This star is about 15.5, but shows eclipses to ~16.5. DW Cnc. About 14.8, evening only. Our prime northern target of the season, but the season is waning. V533 Her - for the early risers! SOUTH. Mysterious new target in Hydra: "Hya" in CV Cat, or EC10578-2935. Look carefully at CV cat - there are a million stars with this "Hya" name, and half a million quite close together in the sky. Some kind of CV factory goin' on there... possibly making weapons of mass destruction. WX Cen. Ubetcha. Let's start up the year's campaign. Bright star, suitable for everyone! Of the australite persuasion, anyway. Back home again after a CLOUDY observing run... joe