From jop at astro.columbia.edu Thu Oct 16 09:39:59 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 16 Oct 2008 09:39:59 -0400 Subject: (cba:news) october observing Message-ID: Dear CBAers, Time to sweep most of the September stars off the stage. V466 And has faded below the limit of our telescopes; on the best of dark nights, we can faintly trace the hump - but not well enough to obtain good data. So let's say goodbye till the next eruption (which is probably many years away). The main center of activity recently has been BW Scl and AO Psc. Berto and Bob Rea have been carrying the torch for the former. This is a very nearby, low-luminosity CV, much like WZ Sge except that it has never erupted. (Presumably it will, but the timescale is 20 years or longer.) Its special interest is the rapid white-dwarf pulsations, and a large- amplitude "superhump" at a period much longer than Porb. This year, it showed the former, and indeed the new data specified their properties better than ever before. But the superhump had vanished. It was worth a few weeks of looking... but now should go into the proverbial cold-case files. AO Psc has been monitored extensively by Bob Rea, Jerry Foote, and Tut Campbell (through George Roberts). The 14 minute pulse and the 3.6 hour orbital signal are well tracked; these basically never fail, and the fast pulse continued its regular spin-up. The star failed to deliver its 4.0 hr superhump, or possible superhump. The latter would be essentially unprecedented, a superhump in an intermediate pola. But we only saw it once; it lasted for a full two weeks, but the frequency was *exactly* 6.00 cycles/day... and the numerical coincidence was just too much for me to accept. So I've been trying to conform it. No help from the 2008 data... and time to move on. While the Moon is bright, the best northern target is V592 Cas, a 12th mag novalike which we have not substantially observed in years. It flashed a nice normal (apsidal) superhump last time around, and a marginal negative superhump. It's beautifully placed in the midnight sky these days, and a great target for all-night observation. With long nightly coverage in Europe and the USA, we should be able to explore the superhump "spectrum" far better than anything to date. The other priority northern target is V455 And (=HS2331+3905), also very well placed in the sky and equipped with a fascinating set of periodic signals - which we're tracking. This star is now around V=15.7, a tough target for bright and/or marginal skies - but plenty bright enough for good conditions. In the south, there's a great opportunity provided by VY Scl's falling down into a low state. The (very) bad news is that it's 18th magnitude... but one theory for this star predicts a very strong orbital modulation after the star dives into a low state. This would arise because the white dwarf is very hot and can power a strong "reflection effect" off the secondary. So it would be very desirable to detect, or set a limit on, any orbital signal in this star. So if you can handle the brightness, give it a shot! Speaking of 18th mag stars in the southern sky, consider RX0232-37. This newly discovered dwarf nova has long faded since outburst, and we don't quite know how bright it is. Possibly as faint as 18, its normal quiescent level. But it's an extremely important star, quite nearby and will eventually teach us a lot about the rarest of dwarf-nova erupters. Can you possibly observe it, and obtain time series? Granted, that's a long shot! A more manageable, but still ambitious, target is ES Cet - still the shortest-period (confirmed) CV in the sky. This is the 9-minute AM CVn star, and we've been tracking its orbital period change to constrain its emission of gravitational waves. Someone else might, or might not, find those waves directly... but we can definitely measure its effect, the change in orbital period. It's a pretty healthy signal, about 10%, and the star is decently bright (16.5-17) if your skies are good and the Moon isn't lurking too near. You probably won't be too thrilled with your signal-to-noise... but pretty good timings can be obtained from quite homely data, when the periodicity is as simple as in this star (basically a sinusoid). Still more manageable (vastly) in the south is FO Aqr, for which we still need abiut a dozen timings to pin down the behavior for 2008. As a reminder, many CBAers are planning to attend the AAVSO/IAPPP meeting in Big Bear (California) in late May... and I'm planning on the Tucson CV workshop in mid-March meeting as well. You might want to think about these - esp. the former. I had been planning on the Hawaii New Years' conference as well, but now it looks like family health issues will keep me from travelling for quite a few months. Enjoy that October observing - the best time of year for us in the northeast USA. joe From jop at astro.columbia.edu Sun Oct 19 07:30:09 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 19 Oct 2008 07:30:09 -0400 Subject: (cba:news) [Fwd: HS 2219+1824 possible superoutburst] Message-ID: <48FB1A41.9000504@astro.columbia.edu> Dear CBAers, Patrick's note on HS 2219+1824 is well worth your attention. This is a very interesting, fairly nearby CV with the white dwarf and secondary star both visible in the spectrum (quite a rarity). Past observations in superoutburst have been kind of sketchy, and an October eruption is happily timed for long time series for northern observers. At 12th magnitude, what's not to like? Good for not-too-far-south australites, too. Even fairly short runs at the off-longitudes (e.g. AU/NZ) sharpen up the power spectrum A LOT... and this gives access to information around the harmonics (which can be revealing of disk structure). A nice paper to read, with a chart and many details, is Rodriguez-Gil et al. 2005, A&A, 431, 269. As usual, good eruptive targets should supplant the nonerupters as campaign stars. Plenty of time for the latter once the erupters have faded. On the other hand, there's always a chance this is a *normal* outburst - which are basically featureless photometrically and spectroscopically. In a day or two, we'll know. And maybe you'll know - the detection of superhumps is the gold standard for superoutbursts. joe -------- Original Message -------- Subject: (cba:news) HS 2219+1824 possible superoutburst Date: Sun, 19 Oct 2008 04:40:57 +0000 (GMT) From: Patrick Schmeer Reply-To: cba-chat at cbastro.org To: CBA News Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany: HS2219+1824 20081017.79 <135 SPK HS2219+1824 20081018.787 120 SPK bright (superoutburst?) This is an excellent opportunity to study a bright outburst of this relatively 'new' SU UMa-type dwarf nova from the very beginning. Time-resolved photometry is strongly recommended. Precise coordinates (J2000.0): R.A. 22h21m44.79s, Decl. +18o40'08.3" Clear skies, Patrick __________________________________________________ Do You Yahoo!? Sie sind Spam leid? Yahoo! Mail verf?t ?er einen herausragenden Schutz gegen Massenmails. http://mail.yahoo.com ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Sun Oct 19 07:49:54 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 19 Oct 2008 07:49:54 -0400 Subject: (cba:news) [Fwd: NSV 1485 and HS 2219+1824 in outburst] Message-ID: <48FB1EE2.6030105@astro.columbia.edu> Oh, and NSV 1485 is very deserving of attention too! Another recent discovery which so far has not received good coverage. Tonny and Tom found superhumps a few years ago, but the present outburst (if a super) offers the best opportunity yet to track superhumps over the full course of eruption. 2000 coords are 4 12 36.9 +69 29 06. There's a 15th mag star just east of the variable. Very flashy baubles in the northern sky. How can you resist? If, that is, they're truly superoutbursts. The first superhump tells the story. joe -------- Original Message -------- Subject: (cba:news) NSV 1485 and HS 2219+1824 in outburst Date: Sat, 18 Oct 2008 19:34:59 +0000 (GMT) From: Patrick Schmeer Reply-To: cba-chat at cbastro.org To: CBA News CC: Emile Schweitzer , AAVSO Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany: NSV1485 20081018.780 132 SPK HS2219+1824 20081017.79 <135 SPK HS2219+1824 20081018.787 120 SPK bright (superoutburst?) Both stars are SU UMa-type dwarf novae. Regards, Patrick __________________________________________________ Do You Yahoo!? Sie sind Spam leid? Yahoo! Mail verf?t ?er einen herausragenden Schutz gegen Massenmails. http://mail.yahoo.com ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Sun Oct 19 17:37:25 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 19 Oct 2008 17:37:25 -0400 Subject: (cba:news) V1251 Cyg in eruption Message-ID: <48FBA895.9060501@astro.columbia.edu> Dear CBAers, We've been waiting for this guy to erupt for a very, very long time (since 1991). The superhump period at that time was 0.076 d - common enough, but the humps took a very long time to develop - and stars of that type usually have very small secondaries. That's odd for a star of fairly longish period (long, that is, within the SU UMa class). That combination fingers V1251 as a suspected member of the very evolved, "period bouncer" class. I've been sporadically trying to find evidence to evaluate this since 1995, but photometry at quiescence has revealed nothing. Now this! From the brightness, my STRONG guess is that this is a superoutburst... and this is without doubt the prime target of the (northern) fall, and possibly the year. It's likely early in the outburst too - 12.5 is about as bright as ever seen. A superb object for time-series photometry in the next few weeks! joe -------- Original Message -------- Subject: [baavss-alert] RE: [cvnet-outburst] V1251 Cyg outburst Date: Sun, 19 Oct 2008 22:54:13 +0200 From: Eddy Muyllaert Reply-To: baavss-alert at yahoogroups.com To: , , References: <20081019202954.898BC54002 at monty.telenet-ops.be> Very rare outburst V1251 Cyg confirmed! V1251 CYG OCT 19.8646 12.5 OUTBURST! Congrats Hubert! Regards, Eddy Muyllaert (MUY) Oostende Belgium _____ Van: cvnet-outburst at yahoogroups.com [mailto:cvnet-outburst at yahoogroups.com ] Namens Hubert Hautecler Verzonden: zondag 19 oktober 2008 22:30 Aan: cvnet-outburst at yahoogroups.com Onderwerp: [cvnet-outburst] V1251 Cyg outburst It seems this one is in outburst. Can someone confirm? According the LGC of the AAVSO is the last outburst more then 10 years ago. V1251 CYG 2454759.3340 12.4 HHU OUTBURST clear skies, Hubert VVS Werkgroep Veranderlijke Sterren http://www.vvs. > be/wg/wvs/ [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] __._,_.___ Messages in this topic (1) Reply (via web post) | Start a new topic Messages | Files | Photos | Links | Database | Polls | Members | Calendar -------------------------------------------- Visit the BAA Variable Star Section web site at... http://www.britastro.org/vss/ -------------------------------------------- Yahoo! Groups Change settings via the Web (Yahoo! ID required) Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe Recent Activity * 2 New Members Visit Your Group Yahoo! News Kevin Sites Get coverage of world crises. Yahoo! Groups Stay healthy and discover other people who can help. Featured Y! Groups and category pages. There is something for everyone. . __,_._,___ From jop at astro.columbia.edu Thu Oct 23 09:12:01 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 23 Oct 2008 09:12:01 -0400 Subject: (cba:news) (cba:chat) V1251 Cygni Prelim results In-Reply-To: <48FFF94B.9010803@warren-wilson.edu> References: <48FFF94B.9010803@warren-wilson.edu> Message-ID: <49007821.30904@astro.columbia.edu> From my inspection, I'd guess that Don's report is the first sign of the just-developed superhumps. The Eastern USA doesn't get many firsts in observational astronomy! True to form, V1251 Cyg appears slow off the mark. (Recent data by Bob Koff and Tom Krajci showed only a few waves of uncertain parentage.) So I guess V1251 is more of a long-distance runner. Anyway, it should start to produce handsome light curves right about now, or very soon. joe dcollins wrote: > A 2.5 hour run at Warren Wilson College in N. Carolina for V1251 shows > about 0.1 mag P-P oscillation with about a 0.75 day period. See my > prelim results at: > http://www.warren-wilson.edu/%7Ephysics/CVResults/V1251Cyg/V1251Cyg.html > > Don > > From jop at astro.columbia.edu Thu Oct 23 09:14:49 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 23 Oct 2008 09:14:49 -0400 Subject: (cba:news) now the real superhumps in V1251 Cyg Message-ID: <490078C9.3090203@astro.columbia.edu> Aha, and Tom's data later on last night (after darkness rolled around to New Mexico) shows obvious large superhumps. Let the time series rip! joe From jop at astro.columbia.edu Mon Oct 27 22:48:32 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 27 Oct 2008 21:48:32 -0500 Subject: (cba:news) UW Tri and KP Cas Message-ID: <49067D80.6080106@astro.columbia.edu> Dear CBAers, Gracious, two more rare erupters at 14th magnitude tonight! Not much known about either, but UW Tri is a bona fide WZ Sge star and very likely to flash an impressive light curve. I'm (almost) away from email now... but these are really good targets. The fact that they're all coming together sounds like "crying wolf" - but honest, these are very bashful stars jumping out of the darkness - and hopefully into your telescope. Back to normal email late tomorrow. joe From jop at astro.columbia.edu Tue Oct 28 14:04:48 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 28 Oct 2008 13:04:48 -0500 Subject: (cba:news) KP Cas Message-ID: <49075440.6070509@astro.columbia.edu> Jeremy Shears and Mack Julian found beautiful 2.07 hr large-amplitude superhumps last night. Let 'er rip, the target is beautifully placed (for borealites), and is a virgim superhumper. But mind UW Tri as well - my guess is, it's putting on a similar act. joe From jop at astro.columbia.edu Wed Oct 29 20:53:06 2008 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 29 Oct 2008 20:53:06 -0400 Subject: (cba:news) a crowded stellar menu Message-ID: <49090572.5010109@astro.columbia.edu> Some really beautiful light curves of KP Cas rolling in now - a large-amplitude superhumper. But don't leave V1251 Cyg and UW Tri unexamined! As far as we can tell right now, each is a very rare erupter - a WZ Sge star, more or less - and no one yet knows which is going to cough up its secrets more readily. Catch 'em while they're bright! Bob Rea is firing away on RX0232-37 and ES Cet, and we could really use more coverage. They're faint, but the Moon's outa the way and the season's good. joe