From jop at astro.columbia.edu Wed Mar 6 18:45:36 2002 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 6 Mar 2002 18:45:36 -0500 (EST) Subject: (cba:news) GK Per in outburst Message-ID: Dear CBAers, As some of you know, GK Per just jumped into outburst. Not the greatest placement in the evening sky - we put Perseus to bed a long time ago - but the scientific interest here is in the properties of the 351 s signal well known from the X-ray (and with some effort seen in the optical as well). Even though Perseus will only be up a couple hours, that's long enough to get about 20 cycles of the oscillation... and hence to get a measurement or useful upper limit. The present campaigns on BP Lyn, TT Boo, and EC0511 are going very well... but see if you can pop off some observations of GK Per in the early evening. Full CBA letter coming Friday. joe From jop at astro.columbia.edu Mon Mar 11 11:06:40 2002 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 11 Mar 2002 11:06:40 -0500 (EST) Subject: (cba:news) March stars Message-ID: Dear CBAers, Some news notes on campaigns... The campaign on BP Lyn was intense, led by Tonny, Jerry Foote, and Dave Skillman. Just one week of data, but it was very dense, and led to a severe upper limit on the presence of superhumps (<0.017 mag). Very nice - and weird - orbital light curve. We'll print it in the atlas that Jonathan is preparing. So... out with BP Lyn, we've got all we want from it. So far, the vigil on EC0511-7955 has been just Bob Rea and Berto Monard. The star has been fascinating... any reinforcements out there? We're going to keep gunning for this star. The prime target this month is a quite faint star, at V=17.6. Its full name is 1RXS J105010.3-140431, but let's call it RX1050-14. Normally I don't like to recommend stars this faint to the CBA, but this one is just too interesting to pass up. It appears to be a close relative of WZ Sge; a recent paper (A&A 376, 448) suggested a secondary-star mass of ~0.02 Mo or so. Virtually nothing is known about variability (hence its lack of a variable-star name), so anything we find is big plus. An actual outburst, or even - gasp - a superoutburst, now that would be precious! This is also a BOTH-HEMISPHERES TARGET... a good chance for us to get true round-the-world coverage (atoning for our lack of representation in East Asia and South America). A finding chart is in the just-cited paper by Mennickent et al. It looks like there is a suitable comparison star about 1.4 arcmin E of the variable. We've gotten only a little coverage on GK Per, mainly from Brian Martin (who claims the first CBA frozen-butt award, richly deserved, for observing in -30 C weather). To my amazement, Brian's data showed strong 6-minute oscillations. So this becomes a great first object of the night for you borealites! Finally it's time to wake up AM CVn again. One of our top-gun CVs. In addition to the 1051/525 s period which we have already studied enough, there is a 1028 s signal, slightly weaker and signifying the orbital period. We have not timed this signal in about 4 years, and we need to acquire a 2002 seasonal timing to check for changes in orbital period. Good target for northern scopes. We like that comp star just 2 arcmin south of AM CVn. So: in the north, GK Per, RX1050-14, AM CVn in the south, EC0511-7955, RX1050-14 Happy observing! joe From jop at astro.columbia.edu Fri Mar 22 06:42:00 2002 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 22 Mar 2002 06:42:00 -0500 (EST) Subject: (cba:news) v803 cen erupts... Message-ID: into a supermax. Sound general quarters. Fire when ready (don't wait till you see the whites of its eyes). We've only caught this star once, for one night, in full superoutburst. Go for it! The supermax was caught by Rod Stubbings... so it comes from the horse's proverbial mouth. joe From jop at astro.columbia.edu Thu Mar 28 10:26:27 2002 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 28 Mar 2002 10:26:27 -0500 (EST) Subject: (cba:news) v803 cen drops Message-ID: Dear CBAers, Well, we got 5 beautiful nights on V803 Centauri in supermax, thanks to Fred & Jennie, Berto, and Bob Rea. Last night it dived by a magnitude. I dunno what it will do now, but let's make it the premier object for tree-to-tree coverage. We can retire ec0511-7955 for the season; it will was a helluva campaign (mainly bob rea and berto), showed the star to be an eclipsing binary with P=0.141466 d, with nodal superhumps and a very prominent nodal precession period of 3.77+-0.05 days. Well done... now let's go after V803 with all available armaments. joe From jop at astro.columbia.edu Fri Mar 29 19:51:47 2002 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 29 Mar 2002 19:51:47 -0500 (EST) Subject: (cba:news) helium week at the cba Message-ID: Dear CBAers, Oops in the last message I forgot our folks from northern climes. Here's the simple menu for the north: 1. GK Per - grab it in early evening! Brian Martin's coverage shows that the 6-minute oscillation is plenty strong in the current outburst. Get good time resolution (a minute) to bring that sucker out! If you have a blue filter available, that would give an advantage... but unfiltered is OK. Since the period is 6 minutes, a 2-3 hour run would be just fine. 2. AM CVn. We're trying to get a seasonal timing of the 1028 s oscillation - having not gotten one in 3 years. One solid week of coverage will give us that timing, or 2-3 weeks of sporadic coverage. 3. CR Boo. Not yet ready for the big round-the-globe campaign. But wherever you live, CR Boo is coming nicely into view. Feel free to kick it off! And, for australites only of course, I plead for a big campaign on V803 Centauri. Keep the proverbial candle burning. By the way, I forgot to include Greg Bolt in the list of the V803 Cen perpetrators. Greg is back after a long break from the CV biz. Since he anchors down our western outpost in Perth and has done some very nice photometry on CVs (esp. TU Crt), we are firmly of the "be nice to Greg" persuasion. Also, our papers on HT Cam (Kemp et al.) and RX2329+06 (Skillman et al.) were accepted and I think scheduled for the June PASP. WZ Sge went back to the journal today after a round of revisions. I'm pretty sure this is the version that will appear (and I feel a bit giddy after sending the enormous thing back into action). I intend to send copies to all collaborators next week; but if you want to be really, really sure of getting a postal copy, write. Jonathan may send out a pdf file, but it will be really big - probably 40-45 journal pages with 21 figures. joe