From jop at astro.columbia.edu Tue Aug 4 18:18:42 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 4 Aug 1998 18:18:42 -0400 (EDT) Subject: (cba:news) V1504 Cyg Message-ID: <199808042218.SAA20801@tristram.phys.columbia.edu> Dear CBAers, I wanted to add my voice to Tonny's recommending photometric coverage of this little studied dwarf nova, now probably in superoutburst. If I understood my recent mail, it was clear tonight in the Crimea and Belgium, and now let's follow up with a good run from the norteamericanos! I think the lunar invasion has knocked out RX1940-10 for the next 4 nights. By that time we'll have a chance to see whether the V1504 Cyg watch yields the hoped-for waves. Elena Pavlenko's first report was positive - but at a period rather longer than the expected 0.07 d. V Sge's a nice target for the *really* bright nights, too. joe From jop at astro.columbia.edu Wed Aug 5 07:06:02 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 5 Aug 1998 07:06:02 -0400 (EDT) Subject: (cba:news) another helium friend? Message-ID: <199808051106.HAA22270@tristram.phys.columbia.edu> Dear CBAers, Well, it looks like Mike Schwartz may have serendipitously found another helium dwarf nova, and it may even still be bright (superoutburst?). If so, we should pounce on it forthwith! I'm inclined to give this object the highest priority right now, though I still think V1504 Cyg is eminently worthy. I attach the present info on the new star. Think about how to deal with that annoying galaxy. For at least a week we should forget V1315 Aql. We've had very good coverage from Daves East and West, and Gianluca Masi. The waves are pretty well defined, and not likely to improve much with further data. RX1940-10 is another story. That one's worth relentless coverage for the next 8 weeks (except when it's clobbered by moonlight, like right now). Please send me anything you have on V1504 Cyg and the new helium star, I promise to study it right away! By the way, isn't anyone around in the morning sky? V592 Cas and TT Ari are back and awfully bright - we very much want early-season coverage so we can tie together the cycle count for 1997 and 1998. joe BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.167 1998, August 04 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: Tonny.Vanmunster at advalvas.be TEL. 32-11-831504 CVC Web Page : http://www.cbastro.org/cvc =================================================================== New cataclysmic variable in Draco ================================= We have been informed by Michael Schwartz, Cottage Grove, OR about his discovery of a new cataclysmic variable in Draco : "I am 'responsible' for finding supernova 1998di in an anonymous galaxy (see IAUC 6982, that was issued on August 3rd). However, spectral observations now reveal that this is not a supernova, but a galactic dwarf nova in outburst, projected near a distant anonymous galaxy". Michael Schwartz kindly has sent us full details about the related spectrographic analysis by Jha, Garnavich, Challis and Kirshner (Center for Astrophysics), that likely will appear in an IAUC tomorrow. The spectrum of the new dwarf nova resembles that of the helium dwarf nova CR Boo near maximum (Patterson et al., 1997, PASP, 109, 1100). The new object is located at RA = 19h24m38s.19, Decl = +59o41'46".7 (equinox 2000.0), which is about 0".6 east and 3".8 north of the nucleus of an anonymous galaxy. A picture of the new object is available at the following URL : http://www2.netcom.com/~pfactors/tenagra.html Some photometric observations : 1998 Jul 22.46 UT, [19 (M. Schwartz, unfiltered CCD image); Aug 02.48 UT, 16.8 (M. Schwartz, unfiltered CCD image); We strongly recommend CCD observers to photometrically monitor this object. Tonny Vanmunster From jop at astro.columbia.edu Thu Aug 6 16:38:49 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 6 Aug 1998 16:38:49 -0400 (EDT) Subject: (cba:news) The Other Hemisphere Message-ID: <199808062038.QAA26263@tristram.phys.columbia.edu> Dear (mostly southern) CBAers, Aug 6, 1998. CV news lately has had a rather northern bias. This is to remedy that shameless display of hemispheric incorrectness! The one star for which we are continuing long coverage is V1432 Aql = RX1940-10. In a couple days the Moon will be outa the way, and I hope that you take a crack at this star. We do need somewhat long coverage though (>3 hr). It averages about mag 15.5 so will be hard for the smallest scopes. On the other hand the modulation is very large, a full magnitude and that's not counting the very deep eclipse. But most of the stars I have to recommend are easier. We finished with V1315 Aql, and now want to turn to the next SW Sex star up there. That's UU Aqr (not Aquilae, which is also a CV, but Aquarii). It's usually at magnitude 13.5, very nice for all of us. It gets attacked by the Moon once a month, but at this brightness the attack is brief. I especially recommend it for the next 10 days; Jonathan is in Chile and it's a very good time to get long runs at other longitudes so we can resolve cycle-count issues. By the way, it eclipses every 3.9 hrs, and a finding chart is in the original Downes- Shara atlas (Feb 1993 PASP). There are three good DQ Her stars lurking up there these days: V1223 Sgr, FO Aqr, and AO Psc. We need pulse timings for all three . The advantage of these is that you get a result (a pulse timing) in about 1.5-2 hr, a pretty good return on investment. And they're nice 'n bright (13.7 or so). And you can scatter the coverage as much as you like, because the period changes we look for are long-term -- over years. Whereas our superhump studies greatly reward *density* of coverage - long runs on successive nights. We're finished for the year with V603 Aql and V1315 Aql. We still want coverage on V592 Cas, TT Ari, V Sge! Really nice objects for northern smallscopers. Long runs very desirable. V1504 Cyg is superhumping as we had hoped; Tonny and Dave West got nice light curves on the same night, and I think Elena did too. A few more nights should give an accurate period measurement. As for that helium star in Draco, well it's a faint sucker and so far I'm not sure anyone has gotten a time series. But maybe. Maybe Mike Schwartz. There's an article on the CBA coming out in the October issue of S&T, I think. Thanks to all who sent pics. I think that they will say nice things about us (especially since they let me write most of it). Unfortunately they did edit out a table with names and scopes of CBAers; that was a bummer. But I hope it'll lead to more expansion into distant lands. I also hope to see some of you, maybe, at the Canadian "Starfest" in two weeks. For Stan and Paul and Marc (our rather amazing New Zealanders): I really recommend UU Aqr for a few weeks! joe From jop at astro.columbia.edu Sun Aug 9 08:35:28 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 9 Aug 1998 08:35:28 -0400 (EDT) Subject: (cba:news) ex hya at last Message-ID: <199808091235.IAA03085@tristram.phys.columbia.edu> Dear CBAers, Zowie! Apparently EX Hya just jumped into outburst (9.5 last night). The placement isn't good but by patching together runs from various southerly observers around the world, we might be able to construct a decent light curve. The orbital period is 98 minutes. If you can possibly get an orbit in the early evening, that would be great. This one courtesy of Rod Stubbings. Certainly one of the planet's best observers of dwarf novae. joe From jop at astro.columbia.edu Fri Aug 21 10:53:09 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 21 Aug 1998 10:53:09 -0400 (EDT) Subject: (cba:news) fashionable stars for aug/sep Message-ID: <199808211453.KAA01092@tristram.phys.columbia.edu> Dear CBAers, 8/21/98 I'm about to leave for "Starfest". Dunno exactly what it is, but appears to be a mass gathering of astronomers in the northern woodlands of Ontario. Sounds like fun. Maybe some CBAers lurk in those sylvan regions. We're still going full-bore on UU Aquarii and V1432 Aql (RX1940-10). The former is an eclipsing SW Sex star - we've found that many of them, and quite possibly all, have negative superhumps. So we want to keep fishing for 'em. In addition, the eclipsers among them give the opportunity to map the distribution of light across the disk, as a function of precession phase. That should reveal the varying shape of the disk. Both targets are near-equatorial, and the former is probably bright enough for all. Long runs are greatly preferred, as usual. Jerry Gunn and Dave Harvey have been watching FO Aquarii, that's a relief. But nobody is watching AO Piscium, which I think is as good a target (and is considerably more desperate). Won't someone adopt this orphan? And in the northern morning sky, let's welcome TT Ari and V592 Cas. In the (far) south, AH Men. Old pals come back. Oh, yeah: (1) Some new wrinkles on the web page. A way for you to request materials, and for us to keep track of your equipment. (We get toys occasionally.) (2) Rumored article on CBA in October Sky and Tel. Haven't seen it though. joe