From jop at astro.columbia.edu Sun Jan 5 09:17:08 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 5 Jan 2003 09:17:08 -0500 (EST) Subject: (cba:news) new year, new stars Message-ID: Dear CBAers, Whew, two weeks away from classes and burrowing into the treasures of CBA data - what a great break it has been! We're readying a paper on new superhump and orbital periods of ten dwarf novae, or twenty if John Thorstensen lets me pollute the "pure" spectroscopic Porbs with filthy things like photometry. About a month away I reckon. In the never-ending struggle for control of the CV sky, the edge has swung decidedly to the south. The campaign on EC0422-20 has been superb with Berto and Robert Rea performing their usual yeoman service, and a strong supporting cast (Greg Bolt, David Messier, Jerry Foote, Lew Cook, Tom Richards, and especially Jeff Robertson). The star has very powerful negative superhumps at 3.32 hrs, plus the nodal signal that is typical of these stars. Since it is also 12th magnitude, it's a star that's likely to teach us something... and we should keep covering it sporadically for YEARS - so we can follow the (probably drifting) O-C and see how period and amplitude are affected by luminosity state. This is likely to become the prototype negative superhumper, if we can keep the faith. But that's for sporadic coverage, not for the all-night-all-week-all-month style that is our usual modus operandi. For the latter, the best southern objects right now are: 1. NSV 10934, at 18h 40m 52.4s -83d 43' 9.5" (2000). It's now about 12th mag, but seems to fade to 15th. A just announced SU UMa star with freshly born superhumps. At this brightness level, this is a star that should command our immediate (and prolonged) attention. Long time series for as long as the star stays above your horizon. (Ha, ha, ha.) 2. EC 05565-5935, a 14th mag star at 05h 56m 32.8s -59d 35' 40" (1950, please note unusual epoch). The next in our series of studies of Edinburgh-Cape novalikes. At 14th mag and with Porb apparently near 3.4 hr, it definitely looks like one of our family. AND NOW FOR THE NORTH... Adios to EC0422-20, except for the occasional run to track phase. FS Aur is another star that should remain on the menu for occasional runs mainly to track phase. It continues to stump us - unrelated spectroscopic and photometric periods. Curses. To evaluate the stability of Pphot, we need to track the phase with a 3-4 hour time series every couple of weeks. V1062 Tau. Oh, fiddlesticks. What a tough star. Eve Armstrong just obtained many long runs on it from the 1.3 m. We learned that the published period is aliased... but the periods are uncomfortably long and the star is faint and gets ravaged by the Moon a lot. I was surprised that Cap'n Bob's recent data was of such high quality - revealed about as much as the 1.3 m. But I tend to think that was a rare confluence of luck (skies) and skill (experience). Plus maybe the star was having a good day. I think we should take this star off the CBA menu. The flashy new target is DW Cnc, in the Downes-Shara catalogue. It's doubly-periodic in the spectroscopy and triply periodic in the photometry. All of 'em stable. Whooppee-do! An obvious new DQ Her star. Let the good times, and delta mags, roll. The other new targets for coverage are BZ Cam (very bright, good for smallscopes but you need *long* time series) and PQ Gem. We've taken cracks at 'em in the past, with results that tantalized but didn't quite deliver the goods. I especially hope the Euros will appreciate that dec of BZ Cam, and get some timeseries which will inspire gringos and other borealites to match 'em! January... that means Rookie of the Year awards. There were two candidates strong enough to win in a typical year: Berto Monard and David Messier. Berto's light curves would obviously have won on pure merit, but some committee members felt that his amateur and rookie status were both questionable (professional scientist, famous visual observer). In what might be described as an anti-Ichiro effect (rumor has it that the committee included some baseball fans), Messier won in a close vote. The actual prize is still a closely guarded secret. Joe From jk at cbastro.org Sun Jan 5 17:32:23 2003 From: jk at cbastro.org (Jonathan Kemp) Date: Sun, 5 Jan 2003 12:32:23 -1000 (HST) Subject: (cba:news) Re: new year, new stars In-Reply-To: Message-ID: Hi CBAers, Additionally, charts for both NSV 10934 and EC 05565-5935 are now available on the CBA web site. Both stars are also in the Downes et al. online CV catalog under the not-quite-exclusive labels of "Oct" and "Pic", respectively. Jonathan CBA Hilo JT> For your convenience, here's the precessed coords of that object Joe JT> mentioned: JT> JT> 1950.00 : RA = 5 56 32.80, dec = -59 35 40.0 JT> 2000.00 : RA = 5 57 12.68, dec = -59 35 26.4 JP> 1. NSV 10934, at 18h 40m 52.4s -83d 43' 9.5" (2000). It's now about JP> 12th mag, but seems to fade to 15th. A just announced SU UMa star JP> with freshly born superhumps. At this brightness level, this is a JP> star that should command our immediate (and prolonged) attention. JP> Long time series for as long as the star stays above your horizon. JP> (Ha, ha, ha.) JP> JP> 2. EC 05565-5935, a 14th mag star at 05h 56m 32.8s -59d 35' 40" (1950, JP> please note unusual epoch). The next in our series of studies of JP> Edinburgh-Cape novalikes. At 14th mag and with Porb apparently near JP> 3.4 hr, it definitely looks like one of our family. From jop at astro.columbia.edu Tue Jan 14 12:35:03 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 14 Jan 2003 12:35:03 -0500 (EST) Subject: (cba:news) winners and losers Message-ID: Dear CBAers, Well, the biggest loser in many years is EC05565-5935. I can't figger out what's wrong with this star - but it's not doing anything (substantially not varying) and the penalty for such malfeasance is immediate suspension. Shame on me for ever suggesting it. NSV10934 is putting on quite a show in the night sky of Victoria. We're getting lots of lovely data from Chris Stockdale, Peter Nelson, Tom Richards, and Bernard Heathcoate. I don't know too much about this group of Aussies fairly new to us... but they all seem to be rather expert with CCD data. Plus they all seem to live "down the road" from each other (and from Rod Stubbings). That is one *amazing* road! Anyway, NSV10934 is now fading but it has a good chance of being bright enough in quiescence to nail the orbital period - which would give us a nice bookend-pair of (Porb, Psuperhump), an item we greatly cherish (and which tells us the mass ratio of the underlying binary). So it's a good object for continuing. The other southern objects now are: 1. T Pyx. An old favorite. We've been tracking the 1.8 hour variation now for a few years, and probably will published the result after one more season. About 2 weeks of coverage will do the trick. Just nightly long time series of differential photometry, our usual thing. 2. EC 10560-2902 (1950 coords 10h 56m 3.8s -29d 02m 57s). Total newcomer. About 14.0, classified as "novalike". Whatever you find out, you'll be the first to know! How about the north? Well, there's an outburst of UV Gem currently ongoing. It's fainter than 15 now... I'm not sure how much longer it'll be on our radar screens. But Tonny and Arto have observed it, some USA coverage would be mighty nice to break aliases, etc. The first week of BZ Cam data is in. No big humps, but there are some little humps and slow trends that look like good bets for yielding a detection. This is one of the few stars where we have a chance for actual 24-hr coverage, with Europe, North America, and Uzbekistan. It's a *great* target for the smaller scopes. Another good one is the DQ Her star V405 Aur. I'd like to substitute this one for PQ Gem; V405 is brighter, the pulse fraction is higher, and its pulsed light is more broad-spectrum than PQ Gem's (meaning that unfiltered observations are fine, whereas they're somewhat problematic for PQ Gem). Let's give DW Cnc a rest for a few weeks. We'll pick it up later. In 12 days I start an observing run at Kitt Peak, and that'll be a major target of the 1.3 m. I guess AO Psc and FO Aqr are slipping dangerously into the solar glare. So we'll retire 'em. Nobody ever observes 'em anyway - you guys just don't appreciate those exquisite stars. joe From jop at astro.columbia.edu Mon Jan 20 15:00:06 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 20 Jan 2003 15:00:06 -0500 (EST) Subject: (cba:news) For borealites only... Message-ID: Dear CBAers, HT Cam just erupted again, and David Messier got a long night's data plainly showing the 8.5 minute periodic signals. Let's keep it up! Seems likely the star will be bright for just 2-3 days, so gotta jump now. We'd love to track that periodic signal all the way to quiescence. I did a quick analysis of the BZ Cam data so far. Looks promising. Definitely worth clamping your hooks on, for the smallscopers. joe From jop at astro.columbia.edu Thu Jan 23 15:15:59 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 23 Jan 2003 15:15:59 -0500 (EST) Subject: (cba:news) stars new and old Message-ID: Dear CBAers, Well we got GREAT coverage of the HT Cam outburst. It was extremely brief, just 2 days, but we got coverage from CBAs-Finland, Crimea, East, Connecticut, and Utah. Pretty good on such short notice! As many of you know, the star free-fell back to 17th mag - took just one night. So that's it, HT Cam is a wrap. We'll get a pulse timing during the upcoming MDM run. T Pyx is a wrap too. We have a very good pulse timing from AU/NZ (Heathcoate, Rea, Allen) and SA (Monard)... it fits the quadratic ephemeris (indicating a plunge toward self-destruction) very well, and therefore can be basically be shelved for another year. BZ Cam continues to be a fine target for northern scopes. Let's start a campaign on BG CMi, a good target for all hemispheres (at +10 degrees) We did this six years ago and netted only a very good study of the 15 minute pulse. We really want to do a proper search for superhumps. And we have a much better network now, with global distribution (*really* global when Uzbekistan cranks up to full speed). It's a perfect time of year - let 'er rip! So: delete HT Cam, and UV Gem (also returned to quiescence) delete T Pyx lower nsv 10934 in priority slightly - we'd like to get the period in *quiescence*, but is it in quiescence yet? any of you aussies know? I'm about to go travelling again - a 2-week observing run. Kinda anxious about it. It's been a mighty rough week for astronomy. joe From jop at astro.columbia.edu Fri Jan 24 10:54:29 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 24 Jan 2003 10:54:29 -0500 (EST) Subject: (cba:news) Re: stars new and old (fwd) Message-ID: I guess you all got Berto's note... Hi CBA observers, I can't help but notice that after the EC 0556-59 debacle (although nobody could have foreseen this), Joe is now turned hesitant to select another deep Southern target ;-). Yeah. Well, I went for EC10560-2902... but farther south than that, I'm spooked. What happened with EC0556-59, anyway? Is there a problem with the identification? Brian/Patrick/Darragh, can you look at the Downes et al. chart and see if the wrong star is marked? (I'm puzzled because the Chen et al. MNRAS paper showed the usual CV flickering, and we don't see any. The star's too far south for me to check.) Berto's choice for BG CMi comp is a good one, easy to find since it's the star 17" directly N from BG CMi. Just make sure you don't saturate on it. At B-V=0.7 it's a decent color, not horrendously different from the CV. (We really love the blue guys, but the sky has precious few of 'em.) joe The new (equatorial) target-select has a fine sequence in the Loneos list which looks as follows: BG CMi 8 7 31 18.4 +09 57 54 h 0768-1581 14.69 0.51 BG CMi 7 7 31 21.0 +09 57 55 h 0768-1906 14.11 0.43 BG CMi 9 7 31 21.8 +09 57 20 h 14.43 0.85 BG CMi 10 7 31 24.3 +09 54 13 h 0768-1913 13.63 0.50 BG CMi 4 7 31 25.6 +09 56 38 h 0768-0553 12.97 0.57 BG CMi 5 7 31 29.2 +09 56 39 h 0768-1846 12.46 0.71 BG CMi 2 7 31 33.7 +09 55 35 h 0768-0833 12.63 1.17 BG CMi 3 7 31 34.2 +09 57 33 h 0768-1017 13.47 0.47 BG CMi 12 7 31 34.5 +09 54 22 h 14.42 0.79 I would propose star No 5 (alt No 4) as a nearby and adequate C candidate (if it is indeed constant). For unfiltered observations it will shine at 12.05R (alt 12.63R). No listed star is faint enough to be used as a proper K. Possibly stars 7 and 9 come closest with 13.85R and 13.95R respectively. But where are stars 1 and 11 then? Regards and I hope your weather is better than mine, Berto Monard CBA Pretoria joe From jop at astro.columbia.edu Tue Jan 28 07:57:34 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 28 Jan 2003 07:57:34 -0500 (EST) Subject: (cba:news) XZ Eri erupts Message-ID: Dear CBAers, Rod Stubbings reports that XZ Eri is at 15.0 - an eruption. It remains to be seen whether this is a supermax, but XZ Eri has never been seen with time-series photometry in *any* kind of eruption, and it's a star of prime interest since it has deep eclipses (the eclipses selectively cover various parts of the wd+disk+hot-spot, so offer diagnostics that noneclipsing stars don't). So it's a very, very tempting target! I've just got out to AZ, and the sky is very clear and dark. Last night we got a good run on BG CMi, to match up with the runs at other longitudes (Messier, Bolt, Rea). Nevertheless with the big scope we can get very good light curves at high time resolution, so we'll do XZ Eri as the first object of every night for the next several nights. If you can do it, it would be awfully nice to get something from AU/NZ (and Berto said he'd also cover it if clouds ever go away). Nevertheless, this is absolute prime BG CMi season too, and I hope that many of you will keep that vigil up. We're hoping to leave it to smaller telescopes in the USA, and rely on other longitudes to make the study the best possible accounting for this star! joe what a treat to see the night sky again!!! From jop at astro.columbia.edu Wed Jan 29 09:40:28 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 29 Jan 2003 09:40:28 -0500 (EST) Subject: (cba:news) xz eri erupts! Message-ID: Sure enough, XZ Eri is flashing beautiful humps and eclipses! The eclipses are definitely weird, not quite like any other star... but it's a real winner. So far, data from Greg Bolt, Patrick Woudt (SAAO), and here at MDM. Not the greatest sky placement for any of us... but with the spread in longitude, we should manage to clobber the usual problems with aliasing. I hope the other programs don't suffer too much. In particular, BG CMi *is* well placed, and it's performing very well too, with very large (up to 0.6 mag) 15 minute pulses. Plenty of excitement up there. By the way, another program that we (basically Jonathan and I) have been carrying out for a few years on meter-class scopes has been time-series photometry of the most intrinsically faint and rarely erupting dwarf novae - some of which have actually never been seen to erupt (but we have our suspicions). Most live at V=18-22 in quiescence, so not exactly CBA targets. Critical unknowns are: do they ever erupt, and if so how often? I'd be interested in hearing from any of you who have been looking for these stars often enough to have a decent documentary record (presumably of upper limits). Schmeer and Kinnunen - and of course Stubbings - manage to find these things sometimes in outburst, but I have little idea what to assume from non-announcements. Are people looking, or what? Lots of upper limits appear in the vsnet data archive... do most people submit to this, or are people keeping upper limits in private notebooks all over the world? joe From jop at astro.columbia.edu Thu Jan 30 11:26:30 2003 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 30 Jan 2003 11:26:30 -0500 (EST) Subject: (cba:news) look, there's another one! Message-ID: Would someone please close the spigot of erupting, interesting dwarf novae?! It's enough to make an old guy nervous.... and leave some of the children out in the cold. The AU/NZ group did a great job on OY Car in Jan 2000 - probably the second (to WZ Sge, natch) best coverage of any dwarf nova ever. Haven't prepared that set for publication yet, but it's not far off. We *did* publish some quite good coverage of TU Crt (paper by Mennickent et al. 99 I think). So I'm inclined to lay off those guys. XZ Eri is great and the world seems suitably energized by it, so I'm sure that one will stay on our list for a few weeks at least. However, it will soon be below 16 (I imagine) and eventually you'll have to consider it too faint. We have 3 consecutive long nights on it at MDM, and the weather forecast remains good, and we have 8 more scheduled nights on the telescope. So that might secure the USA part of longitude space - if we stay on it. But I'm very chagrined to abandon DW Cnc and BG CMi - prime stars in a prime season, with exquisitely interesting arrays of periodic signals. Those stars are ~14.5 and could be done with smaller scopes... any norteamericanos out there who will swear fealty to DW Cnc or BG CMi? Or maybe Euros, who are likely not tempted by Eridanus? Finally there's GZ Cnc... damn! This short-P dwarf nova also just erupted, and Taichi Kato has reported some very tantalizing wiggles in its light curve. The midnight sky is getting so terribly crowded - and I hate to ignore perfectly placed stars since very long runs are so healthy for our enterprise. I'm going over to Biosphere 2 tonight, and will leave Maddy Reed in charge of the telescope (just in case Sirius B erupts or something, the telephone here is 520-318-8661). The 2.4 m observer is John Thorstensen, so it's an all-CV mountain ridge this week. Back in the observing saddle Monday (though Maddy does most of the observing - I'm better at stuff like "wow, Venus looks great tonight"). The BG CMi campaign is going extremely well, but all this competition is just so fierce! I'll meditate and write again tonight or tomorrow... And also respond to Berto's note... a subject that fascinates me as much as it does him (I think)! joe