From jop at astro.columbia.edu Mon Dec 4 17:33:01 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 4 Dec 2000 17:33:01 -0500 (EST) Subject: (cba:news) TW Pic Message-ID: Dear CBAers, I think I omitted any mention of TW Pic in my last message. Robert Rea and Maria Marsh have been covering this star for the last week; possibly some other southerners too, but that's all the data I've seen so far. The variations are quite extreme, suggesting a very rich spectrum of periodic signals - not that I can figure out what they are! I hope a few others can put it on their southern menu - any interest in Sud Afrika? (By the way, Berto, I'm getting some positive responses here, so maybe we can get those toys soon!) joe From jop at astro.columbia.edu Thu Dec 21 21:08:47 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 21 Dec 2000 21:08:47 -0500 (EST) Subject: (cba:news) TW Pic and RZ Leo Message-ID: Dear CBAers, Tonny's announcement of the superhumps in RZ Leo - just erupted - is wonderful news, and since this is an equatorial target, let us now rally to the support of this star, a fine bright thing at mag 12.6 or so. We've tracked the orbital period spectroscopically and photometrically, and thought we might have to wait another 10-15 years for a superoutburst to learn P(superhump). But now it has arrived. Not the most perfect placement in the sky, but with our longitude range we should be able to say the 24-hour dragon. So this is the top priority star to do! But let me also remind about TW Pic's sterling performance this year. This star looks like it might be trying to tell us something qualitatively new about the period structure in CVs. I've never seen a power spectrum like this one before. Usually that just means "it's very complex". But not here - it's not particularly complex, but flashes some periods (one near 6.5 hr and one near 16 hr) which are just not declaring membership in any of the established categories (spin, orbit, superhump, precession). Robert Rea is doing a GREAT job on this star, and now Fred, Jennie, and Gordon (happily reinstalled in AU) have joined the party. Some help from South Africa or South America would be good, and even Australia (since our main southern power is of course NZ). Let 'em both thrive. These are two great stars for the CBA! joe Not RZ Leo Minoris, another CV of note, but RZ (Big) Leo. Chart in Downes and Shara. From jop at astro.columbia.edu Sun Dec 24 12:29:00 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 24 Dec 2000 12:29:00 -0500 (EST) Subject: (cba:news) heavens on fire... Message-ID: Dear CBAers, It was a quiet (northern) fall, but now the sky's popping off with interesting dwarf novae all over the place. As Tonny says, RZ Leo is definitely the best one goin' up there. Warner and Woudt saw the big superhumps kick in about a day or two ago, so they should be pulsing away up there for... well, I dunno, but maybe 2 weeks. The early coverage by Tonny and Gianluca shows a precursor signal, at P-orb and of undetermined origin. We have a precise Porb in the bank from a few years ago, so whenever we learn the true Psh we can redeem it at full value with the local cashier. Some of our heaviest artillery (Dave East and Captain Bob) is down for repairs. So we need a big effort now, from all latitudes/longitudes/species/planets. Much as I hate to dilute the message, I'd like to remind that TW Pic is doing great and also needs long coverage to document this strange long- period signal that snakes through the light curve. Observations in South Africa and South America (or a boat somewhere?) would be really good! joe From jop at astro.columbia.edu Sun Dec 31 12:43:32 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 31 Dec 2000 12:43:32 -0500 (EST) Subject: (cba:news) stars for January Message-ID: Dear CBAers, Weather has been a big problem with RZ Leo observations, but we've had enough contributions from Europe (Tonny) and North America (Dave East, James Hannon, Brian Martin) to define the star's main superhump period. It reports in at 3.4+-0.2% longer than Porb. This is something of a surprise, as most of the infrequently erupting SU UMas have much smaller period excesses, signifying a light secondary (a few even with M2<0.08 Mo). C'est la vie I guess. If we can get enough more coverage, we might be able to track the Pdot and measure the amplitudes of the quasi-harmonics; these give valuable (though not presently well-understood) information about changes in the accretion-disk structure. So RZ Leo continues to be a great target for all imaginable hemispheres. Track it into the mud. BZ Cam, now there's a different story. BZ Cam is very bright this year, and doesn't show much activity on ~3-hour timescales. I think we should lose this star from our target lists. Brian and Tonny have been observing UV Per, another rare erupter which followed RZ Leo into outburst. This is a good northern target for as long as it's bright. The main superhump period is known, but we can greatly improve on its accuracy and study upper harmonics. Then there are the DQ Hers (the second line of the "Current Targets" list). Old friends that are always happy for visitors, and will reward you too. But you gotta know - and more especially your computer's gotta know - the time to within 10 seconds or so. 1-900-410-TIME is worth visiting! Now for the south. Unnnh, I could hardly overstate how psyched I am about TW Pic this season. Robert Rea, Jennie McCormick, and Fred Velthius have been following it, and finding these long, slow waves which are quite big and obviously signify a strong periodic signal. Unfortunately all the observations are from NZ (no, make that one from AU - Gordon) and the NZ weather has been none too good. So we are really, really hoping to redeem all this great data with more frequent coverage, especially at other longitudes (but NZ too!). Any help you-all can provide would be great. I was also hoping to begin the T Pyx season now. This star is 15.3 and has a very periodic 0.0762 d signal, which we have been tracking for 4 years. The period is changing remarkably fast, and we need to get some densely spaced coverage every year to maintain cycle count. The light curve doesn't *look* like much, but it's practically a unique star - a short-Porb CV blowing itself apart on a timescale of 10 million years! Happy observing north and south. I hope to return with CBA converts from Golconda and the mystic East. joe