From jop at astro.columbia.edu Wed Mar 2 17:28:03 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 02 Mar 2011 17:28:03 -0500 Subject: (cba:news) ER UMa, SDSS1339, CP Pup, BK Lyn, DW UMa Message-ID: <4D6EC473.2050702@astro.columbia.edu> Dear CBAers, Wow, what a bunch of stars in February. ER UMa and SDSS1339+48 continue to light up our sky with beautiful periodic variations! The signals in ER UMa must surely tell us a lot, because they are large-amplitude in a bright star, and very phase-stable. Just ideal for the long term study that has never been feasible in any other star - because the signal vanishes, the star vanishes, or the stability is too low to follow definitively. Keep the faith on through the next superoutburst, and a little beyond - i.e. at least 3 more weeks. SDSS1339+48 still hasn't shown its hand, just recently dropping down to V=15. Will it show echoes? Will the humps stay around for months like WZ Sge/GW Lib? Will the periodic WD pulsations return soon? Will the unexplained large 7 hr period at quiescence pop back up again? All unknown, At some level, we're going to want to follow this throughout the (northern) spring. Definitely good for long time series, which as usual are much more valuable than the short guys. And I have to say, at great risk of crying "fire" too often, that CP Puppis is even more interesting. I was SHOCKED by the first few light curves of Bob Rea - showing a very strong periodic signal at a period considerably shorter than the alleged Porb. That weird signal is still there, but it now appears to be multiperiodic - and it will take a good multi-longitude set of time series to unravel it (separate the closely spaced components). Berto and Bob are doing well with it, and some observations from the southern USA (Tom K and Shawn Dvorak) have been very helpful. I really hope that Greg Bolt (Perth), or some Aussies, can get some suitable runs on it. More generally, I think 2011 is going to be a breakout year for negative superhumps. For years they have been trying, and mostly failing, to break out from my computer. Now they have to, having been liberated by the black magic of ER UMa. There's so much new stuff, I'm not nearly caught up. But I have learned all that. My preliminary analysis on BH Lyn is negative - no discernible humps (other than the variation-cum-eclipse at Porb). So that's probably done for the year. The other two (likely) bright stars to go after now are BK Lyn and DW UMa - also fine negative-superhump specimens that have not been properly published yet. joe joe From jop at astro.columbia.edu Thu Mar 10 05:40:09 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 10 Mar 2011 05:40:09 -0500 Subject: (cba:news) campaign stars in mid-March Message-ID: <4D78AA89.70903@astro.columbia.edu> Dear CBAers, Later today I leave for Kitt Peak, with 13 students in tow (my class). This is mostly for general astronomical tourism, though we have an observing run and will manage to get some time-series runs. I suspect that I won't have much free time for analysis/writing; let's review where things stand now. SDSS 1339 still deserves plenty of attention; keep going until the waves disappear - and then go another week beyond that (since disappearance can merely signify beating with a nearby, closely spaced period). CP Puppis is continuing to delight - me, anyway. The waves are very strong on most nights, but power spectra show that there are *at least* two, and very likely three, closely spaced signals. One is Porb - no great reward there. The other(s?) occurs at a frequency I don't recognize - and which is possibly afflicted by aliasing since we're having trouble getting enough coverage on this star; it's a little late in the observing season, and our lack of South American representation really hurts us. Anyway, keep it up for at least another 2 weeks. ER UMa also shows at least two, and very likely three, signals. Because the star has at three luminosity states (quiescence, max, supermax... plus the transitions), we get to study these signals in different conditions. Sort of do a laboratory experiment on these likely-precession-related signals. That's an exciting prospect. We're 40 days into the campaign, so it's near the end; but I recommend at least another 10 days. It's late for BK Lyn too, but this should be a good star for brighter or inferior nights. Big waves, brighter star. It's time to come back to AM CVn. Not as interesting a target as these guys who sprout the big periodic waves, but a high scientific impact if you're careful with the timing - to probe the long-term period change. Possibly a good target through the upcoming bright-moon interval. It's also a good time to get end-of-season runs on the many northern-winter DQ Her stars: MU Cam, RX0704+26, BG CMi, PQ Gem, WX Pyx, and Swift 0732-13. We'll pick 'em up again in 5 months, and have an absolutely year-to-year cycle count (which most of these stars still lack). Finally, a couple of runs on YY Sex would be great - especially in I light where the signal is very strong. Just to tune up the ephemeris. I'll write again from Kitt Peak, after things settle down. He says, optimistically. joe p.s. Remember the Boston AAVSO/AAS meeting coming up in May (and you need to join the AAVSO to take advantage of their reduced-$$ AAS registration fee... and for the AAVSO mtg... and on general principles). From jop at astro.columbia.edu Fri Mar 18 23:00:26 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 18 Mar 2011 23:00:26 -0400 Subject: (cba:news) SDSS J093249.57+472523.0 outburst, mostly Message-ID: <4D841C4A.9070109@astro.columbia.edu> Dear CBAers, Here's Jeremy's, and Taichi's, note re the outburst of SDSS0932+47. This is definitely a high priority object - usually too faint for us, let's jump to action now. ER UMa is definitely worth continuing. I assume YZ Cnc also, though I haven't done the analysis yet. CP Pup and AH Men for sure. More details in mid-week. My brother-in-law died suddenly a few days ago, and my study of celestial goings-on will take a break. joe SDSS J093249.57+472523.0 outburst! According to baavss alert, this eclipsing CV (likely SU UMa-type dwarf nova) is undergoing its first-ever recorded bright outburst. Observations are encouraged!! === SDSS J093249.57+472523.0 Mar 18.900 14.9C CRTS has V~19. Possible IP with P_orb ~95 min and deep eclipses. See Homer et al. http://adsabs.harvard.edu/abs/2006AJ....131..562H Go well! Jeremy ShearsCheshire, UK === Basic info: SDSSJ093249.57+472523.0 093249.57 +472523.0 UG:(NLDQ:)+E 16.8V 20.6R http://adsabs.harvard.edu/abs/2004AJ....128.1882S (Porb=1.7hr?) http://adsabs.harvard.edu/abs/2006AJ....131..562H (eclipsing P=0.0661618 d, X-ray obs. suggest an intermediate polar) range: CSS range including eclipses (18.0-19.5 outside eclipses) maximum: possible outburst (V=16.8) on GSC2.2 type: the presence of orbital humps in the orbital light curve would suggest a quiescent DN (qUGSU:) but with strong HeII From jop at astro.columbia.edu Sat Mar 26 07:53:20 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 26 Mar 2011 07:53:20 -0400 Subject: (cba:news) cp puppis sets, hp lib and am cvn rise Message-ID: <4D8DD3B0.5080701@astro.columbia.edu> Dear CBAers, We've done some LONG campaigns this year, and I'm scrambling to keep up. I did, however, finish the analysis of CP Puppis, and that star can be retired. I didn't really believe my findings at first - they seemed quite inconsistent with earlier results - but now I see that this is the result of the global campaign, not any actual change in the star. Earlier it seemed that CP Pup had two periods: one consistent with Pspec at 0.06128 d (presumed to be Porb, and I think that interpretation still holds up, although don't bet your life on it) and one 2% longer. That's a pretty familiar pattern, hey? But behold the power of longitude. We have observations from South Africa (Berto, Deanne de Bude), Florida (Shawn Dvorak), New Mexico (Tom), New Zealand (Bob Rea, Si Lowther) and Perth (Greg Bolt). That's the whole Earth, and it's now obvious that the main photometric signal occurs at a much longer period, 0.0660+-0.0003 d. It differs from the more familiar superhump wave in these respects: (1) the amplitude ranges - even on consecutive days - from 0.30 mag to undetectable; (2) the power in long (say 1 week) stretches of data is weak and complex, even when the signal is strong throughout; and (3) the period seems to be ~8% longer than the alleged Porb, as mentioned above. Attached is an average power spectrum from 12 1-2 day stretches of good and densely distributed data. Ugly but telltale. A coherent signal would be a very narrow spike here. Each of these properties is basically inconsistent with the common-superhump family. A few other stars do it - BW Scl and CP Eri do it in spades - but I've never seen it appear in a high luminosity state (of any star). CP Pup is an intrinsically bright star... so this little oddball family will have to make room for another member that is odd even by its standards. I've occasionally in print speculated that this phenomenon results from a superhump at the 2:1 (rather than 3:1) orbital resonance in the disk. Who knows if *that* interpretation can be massaged to accommodate CP Pup! Anyway, the Puppis nights are getting short, and we're done for the season. I hope to write in the next few days of our other large campaigns: ER UMa, SDSS1339+48, and YZ Cnc. Each will end soon... but probably not quite yet. It's definitely time to resume coverage of AM CVn, which took a break after SDSS1339 erupted. And to start up on HP Lib, a nice bright AM CVn star which can be attacked from all hemispheres. Long runs would be mighty nice! Although there is no "CBA meeting" this year, clusters of CBAers will be at the May AAVSO/AAS Boston meeting and the May SAS Big Bear meeting. I'll only be at the former (along with Enrique, Helena, and possibly Jonathan), but the Big Bear meeting is always a good one too. joe -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: CP1-2D.POS URL: From jop at astro.columbia.edu Wed Mar 30 08:22:32 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 30 Mar 2011 08:22:32 -0400 Subject: (cba:news) Fwd: AAVSO Alert Notice 434: Outburst of NSV 1436 Message-ID: <4D932088.3000806@astro.columbia.edu> Dear CBAers, Well, this is certainly worth a major effort to pursue, despite the unfavorable sky position. We might be able to patch something together from our range of longitudes. Thanks, Matt or Arne - for putting this info together (I never heard of it before). joe -------- Original Message -------- Subject: AAVSO Alert Notice 434: Outburst of NSV 1436 Date: Wed, 30 Mar 2011 07:32:22 -0400 From: aavso at aavso.org To: jop at astro.columbia.edu AAVSO Alert Notice 434 Outburst of NSV 1436 March 30, 2011 The cataclysmic variable NSV 1436 has been discovered in outburst. This is the first bright outburst of this star observed since 1948, and followup observations are strongly encouraged. Little is known about the nature of NSV 1436, and observations may help shed light on whether the star is an infrequently outbursting normal dwarf nova, a WZ Sge star, or recurrent nova. The object is currently just a few hours east of the Sun, and will be available for the first half of the night only. Both time-series and multicolor photometry are encouraged. NSV 1436 was discovered in outburst by E. Muyllaert (Oostende, Belgium) at an unfiltered (CV) magnitude of 13.49 on 2011 March 28.9576 (JD 2455649.4576), and was confirmed by M. Linnolt (Hawaii, United States) at a visual magnitude of 12.8 on March 30.2708 (JD 24556450.7708). This star last exhibited a bright outburst in late November 1948 (Brown et al., 2010, JAAVSO 38, 176), and is a known X-ray source (Bedient 2004, priv. comm.). A smaller outburst occurred on 2011 March 9-10, when it briefly reached magnitude ~14.5 (Linnolt: 14.5 on JD 2455629.7618; M. Simsonsen, Michigan, United States: V=14.55 on JD 2455630.6615; Linnolt: 14.55 on JD 2455630.7354). The classification of this object is unclear, in large part because it has been poorly observed in the past. The object is typically fainter than V=16, and has been recorded as faint as magnitude 19. Photometry during the current outburst may provide insight into the nature of this object. NSV 1436 is located at the following (J2000) coordinates: RA: 04 02 39.02 , Dec: +42 50 46.0 A new sequence for NSV 1436 was published in late 2010, and observers should use the new comparison star magnitudes for photometry. Charts and sequences for NSV 1436 may be obtained via VSP: http://www.aavso.org/vsp Please promptly report all observations of this star to the AAVSO using the name "NSV 1436". This AAVSO Alert Notice was prepared by Matthew Templeton. ------------------------------------------- SUBMIT OBSERVATIONS TO THE AAVSO Information on submitting observations to the AAVSO may be found at: http://www.aavso.org/observing/submit/ ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION An Alert Notice archive is available at the following URL: http://www.aavso.org/publications/alerts/ Subscribing and Unsubscribing may be done at the following URL: http://www.aavso.org/publications/email/