From jop at astro.columbia.edu Sat Oct 13 09:54:28 2001 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 13 Oct 2001 09:54:28 -0400 (EDT) Subject: (cba:news) October Stars Message-ID: Dear CBAers, Finally WZ Sge is slinking back into the grass.... At about V=14.3, it still shows some sign of its recent shock - a superhump that refuses to quite to die. But its faintness and proximity to that companion star has made it a very tough target... and you usually don't get rich observing Sagitta in mid-October. So my advice is for most people (northerners; southerners quit a long time ago) to wave goodbye to WZ Sge. Some people are still able to get quite nice light curves - Dave Skillman, Jerry Foote, Captain Bob, and Major Tom (Krajci) are still doing very well. So if you're getting those pretty light curves, hang in there for 2 more weeks! Otherwise, it's time to shift. The three DQ Her stars in the fall sky - AO Psc and FO Aqr especially - remain good targets throughout October. For long-term coverage, the really good targets available now are V592 Cas and TT Ari - both very bright (mag 11.7 and 10.7) and possessing a host of periodic signals. Plus, their sky positions are (more or less) perfect for all-night coverage. Now for the south... The best target now is BW Scl. Aside from being one of those mysterious WZ Sge clones up there, the star apparently - based on the coverage these last 2 weeks by Bob Rea and (General) Jonathan - shows "quiescent superhumps", one of only 2 or 3 stars to do so. It's a superb target - only problem being the brightness (about 16.5). If you can work reasonably at 16.5, make friends with this star and never let go! If that's too faint - and it probably is for most CBAers - then I recommend EC23593-6724 and EC05114-7955, with coords in the last "News" message. Two virginal CVs with a very happy dec. Jonathan, can you send chart info on these guys? Patrick (Woudt), are you reading this? If so, I smell a southern telescope nearby, at an exotic longitude. Jonathan is at Tololo for the same dates as your run. We'd love to get some SAAO coverage on BW Scl to help us decipher the complex periodic signals... and we'd be happy to get some Chilean coverage on your favorite targets, too! joe (He's available at jk at cbastro.org, and I'm at jop at astro. columbia.edu. My email access will be primitive for the next 3 days though, but his is fine) From jk at cbastro.org Mon Oct 15 22:45:47 2001 From: jk at cbastro.org (Jonathan Kemp) Date: Mon, 15 Oct 2001 16:45:47 -1000 (HST) Subject: (cba:news) cba finding charts Message-ID: Dear CBAers-- JP> If that's too faint - and it probably is for most CBAers - then I JP> recommend EC23593-6724 and EC05114-7955, with coords in the last JP> "News" message. Two virginal CVs with a very happy dec. JP> Jonathan, can you send chart info on these guys? For those of you who may not have visited the charts page at the CBA web site recently, we have substantially renovated it and integrated it with the Downes et al. CV web site by providing extensive links to its catalog and atlas pages. The charts section of the CBA web site now contains more than 150 objects, sortable by both constellation and right ascension. While some of the customized information that we produced on our older charts isn't presented for all of the objects, web links to detailed information and finding charts are provided for every CV in the list. However, a link at the bottom of the charts page will still bring you to all of our older CBA-produced charts. Additionally, you will find information about many of the Edinburgh-Cape Blue Object Survey (EC) CVs mentioned in recent CBA messages [many of which were first documented in the recent Chen et al. paper (2001, MNRAS, 325. 89)]. We eagerly solicit comments on this new format, including what parts of it you find useful and what else you'd like to see included on the charts pages. Clear skies at Tololo... Jonathan CBA Hilo From jop at astro.columbia.edu Tue Oct 23 07:57:07 2001 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 23 Oct 2001 07:57:07 -0400 (EDT) Subject: (cba:news) SDSSp_J173008.38+624754.7, a new friend Message-ID: Dear CBAers, Tonny Vanmunster and Arto Oksanen found superhumps in this newly discovered dwarf nova. Tonny's message is below. So far, no observations from North America... let's stand up for our longitude, fill in the gap, and nail down that period! (The star's coords are in the name.) Since the outburst won't last much longer, I'd rate this one the highest-priority evening object right now (above WZ Sge). The two northern targets in the midnight-morning sky are V592 Cas and TT Ari - both very bright, enjoy the light! And the southern target is BW Scl... faint and exotic. joe Dear colleagues, I have now completed a period analysis of SDSSp_J173008.38+624754.7, using the complete set of observations obtained at CBA Belgium Observatory last night, October 22/23 (5.25 hours). The PDM technique yields a superhump period value of 0.0801 +/- 0.0009 d, which is close to the value reported by Taichi below, although not yet completely in line. I will post the complete light curve to my Web site later today. Please continue your follow-up observations, as multi- longitude coverage is needed to secure the outbursting characteristics of this new UGSU CV. With kind regards, Tonny Vanmunster CBA Belgium Observatory http://www.lunarpages.com/cbabelgium From jop at astro.columbia.edu Wed Oct 31 10:42:46 2001 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 31 Oct 2001 10:42:46 -0500 (EST) Subject: (cba:news) Call off the dogs Message-ID: Dear CBAers, Well, as you saw from Tonny's message, mister SDSS1730 slunk back to quiescence, and WZ Sge is getting harder to observe, due to its own fading and the hostility of the western horizon. So it's time, finally, to call off the dogs for both stars. In a month's time we'll have another shot at WZ with a big telescope, and we'll see if we can track the eclipse waveform at that time... but after observing it for 94 out of 95 nights, we should have learned the pattern by now! (And we did.) Whew, what a run, I hope we can rest for 25 more years. Ha. Meanwhile, there are other fish in the ocean. Dave Skillman and Jerry Foote are mounting a big campaign on TT Ari, which is pulsing away with a big apsidal superhump. This is an ideal target this time of year, especially for small scopes since at V=10.8 there are lots of photons available. I hope that we can get some coverage from AU-NZ too... I know you're not thrilled with the dec, but we still have no northern coverage from CA to the Crimea, so we certainly do crave contributions from Australasia and Oceania! In principle, TT Ari should be the star that will teach us all the intricate details of apsidal superhumps, since it is so bright and roughly equatorial. So far, it appears to just flash a very powerful but structureless superhump... but from past experience it seems a good bet that the lack of structure merely reflects a lack of diligence in the campaign. November 2001 is the month to find out. We have also received data on V592 Cas, mainly from Ed Beshore. Kind of a mystery, this one. Two nights showed strong humps, and the other four not. This is sometimes means two closely spaced signals are beating together, slowly travelling in and out of phase. That interpretation seems not to work for the present data... I just can't figger it out based on the present data. So we should either get a lot more, or give up! Since it's a bright star and has a great dec for the Europeans, I'm inclined to say let's hang in there for a few more weeks - and I hope the Euros can bail us out! Finally among northern targets is FS Aur. This will be a major December target, but it's important to get an early start, as the *precise* value of the period is the key datum (to allow phasing with previous years) and that is best served with the longest possible baseline of observation. Another happily northern and decently bright (14) target. It's a great season for northern CBAers! As usual, the best strategy is to settle on one of these stars and fire away relentlessly on it. Now for the south. Thanks to Chen's recent article in MNRAS, identifying numerous results from the Edinburgh-Cape survey for blue stars, we now have a lot of fresh meat for hungry southern photometrists. Among the seasonal targets, the ones that seemed really promising to me are EC23128-3105 23 12 50.0 -31 05 09 V=16.6 (sorry) but P estimated as 1.4 hr EC23593-6724 23 59 21.7 -67 24 28 V=14.3 (oooo) and P~2.0 hr EC05114-7955 05 11 25.1 -79 55 02 V=15.1 and P~3.1 hrs Coords are 1950.0 by the way. I think Jonathan has charts for all on the CBA website. All these stars looks astrophysically pretty interesting to me. The other southern target is BW Scl. We had a wonderful harvest from Chile 2 weeks ago, supplemented by data from Bob Rea. There is one strong and probably stable period in the system, but we do need a longer baseline of data in 2001 to guarantee an accurate cycle count over the season. So we definitely need another 4-6 weeks of coverage. I apologize for the faintness, and the ugliness of the light curve (just not a helluva lot that grabs your eyeball... but oh, does that fourier transform love it!). If you don't mind ugly depressing light curves, observe this star! - otherwise you'll be a lot happier with the above list of 3. Have a great ol' time observing... the ducks are on the proverbial pond. joe