From jop at astro.columbia.edu Tue Sep 10 01:15:10 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 10 Sep 2013 01:15:10 -0400 Subject: (cba:news) MASTER OT J040552.59+274716.7, and others In-Reply-To: References: Message-ID: <522EAADE.7040807@astro.columbia.edu> Dear CBAers, I'm a little communications-hampered here in Sicily for a CV conference... but this (details below, but also see ATEL 5369) definitely looks like it's up our alley. Decently well-positioned, easily good enough for deciphering aliases with a longitude spread among our observatories. Fire away with the usual approach - time series photometry in unfiltered light, preferably with time resolution of 50-80 s or better. Re other stars. V1101 Aql continues to delight, but is now coming off another max, and I'd suggest continuing coverage for just one more week, then quitting. I think the filtered-photometry approach can be ended now. At first glance, the data suggest the usual result for CVs: the periodic signals are white (and thus no significant advantage in using filters - except for very bright targets of course). NR TrA can also be ended now. It was an experiment in defying the onrushing evening twilight. Those experiments always lose in the end... and besides, we got great results. Berto, Josch, Bob Rea, and Gordon Myers manned the ramparts. It amazes me how these "young old novae" have such similar orbital light curves - while all the old guys (novae >50 years ago) revert to their own characteristic and highly varied light-curve shapes. BW Scl is definitely worth continuing. It shows strong "high-epsilon" or "2:1" superhumps - signals exceeding Porb not by ~2%, but more like 7-8%. This phenomenon still doesn't have a name, and most CV astronomers have never heard of it. It's time for us to write a really good paper about them, and I think BW Scl is the ideal excuse for it, because the waves are quite strong, with maxima visible in the light curve (therefore easily timed). Berto, Josch, and Bob Rea have been steadily observing. With some coverage from Greg Bolt (Perth) and Arto(Chile, but with high density of points), we could track this all the way around the globe. The reason that's highly desirable - rather than just a point of pride - is that the waves are *much less stable in phase* than their better-known 3:1 cousins, regular old superhmps. So we gotta track them more closely, at least some of the time. Enrique has begun the year's coverage on PX And, and it's also time (or almost time?) to begin on LT Eri and AH Men. Each of these stars shows positive superhumps, negative superhumps, and "nodal precession" (or anyway, a long-period signal at the beat frequency of orbit and negative superhump. Or at least they did at some point in our scattered coverage in past years. It's time (or maybe almost time - it depends on whether you like morning observing!) for an *intensive* campaign which will nail these results down. Finally, I plead again for coverage of V1494 Aql. Remember that brilliant star in November 1999? Let's give it some love now! Enrique's data confirm the (somewhat shallow) eclipses, and I think also the double-humped light curve that may yield the temperature of the still-hot-and-glowing white dwarf. Can't tell yet re superhumps. It's about 17.2, a pretty hard target - but can be done in good conditions by many of you. Oops, also finally... ASAS-SN13ck is turning out great! Keep the campaign going on that star. BTW my email access is very poor here, and I hope you guys with actual telescopes and live computers will use cba-chat and cba-news to communicate useful stuff in the next 7-10 days, esp. as regards these new or lesser-known targets. joe -------- Original Message -------- ATEL #5381 Title: Spectroscopy of MASTER OT J040552.59+274716.7 in Taurus Author: R. M. Wagner (Ohio State), C. E. Woodward (Minnesota), and S. G. Starrfield (Arizona State) Queries: mwagner at lbto.org Posted: 9 Sep 2013; 16:53 UT Subjects:Optical, Cataclysmic Variable, Nova, Transient We observed the optical transient designated MASTER OT J040552.59+274716.7 reported by Denisenko et al. (ATEL #5369) on 2013-09-06.4090 UT with the 2.4 m Hiltner telescope on Kitt Peak, Arizona. We confirm the presence of a bright transient at the position reported by Denisenko et al. Furthermore, we obtained several spectra of the transient using the OSU CCD Spectrograph (CCDS; range: 366-730 nm; resolution: 0.9 nm). The average spectrum exhibits emission lines of the Balmer series of hydrogen; He I 706.5, 667.8, 587.5 nm; He II 468.6 nm; and perhaps N III 464.0 nm. The equivalent width of H-alpha emission was 1.60 nm and with a FWHM of 1.32 nm (corrected for instrumental resolution). In addition, weaker H-beta and several of the higher order Balmer emission lines are superposed on broad (full-width of 6.2 nm at H-beta) absorption troughs. The spectrum is characteristic of a dwarf nova near maximum light. The appearance of the spectrum and outburst amplitude of at least 7.5 mag reported by Denisenko et al. suggests that the transient is a member of the WZ Sge subclass. Further time-resolved photometric observations are encouraged. -------------- next part -------------- ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Wed Sep 18 15:16:34 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 18 Sep 2013 15:16:34 -0400 Subject: (cba:news) Fwd: [vsnet-alert 16417] New CV in Cassiopeia MASTER OT J004527.52+503213.8 (12.5m)! In-Reply-To: References: Message-ID: <5239FC12.2040408@astro.columbia.edu> Dear CBAers, This looks like one of ours, and it's bright enough to be studied all the way down to quiescence. So let's fire away with gusto! And I think it's finally time to say goodbye to V1101 Aql. The coverage has been magnificant, and so has the star. But let's make way for the new. The only proviso is that we should *briefly* look in on it about 1-2 months hence, to establish a maximally accurate value for the two periods. More later om other stars... joe -------- Original X-DSPAM-Signature: 5239cb1212636719011667 Bright SU UMa / WZ Sge candidate discovered by MASTER-Amur, see ATel #5399 MASTER OT J004527.52+503213.8 20130917.668 12.53C MASTER-Amur 20130917.670 12.50C MASTER-Amur 20130917.688 12.59C MASTER-Amur 20130917.690 12.65C MASTER-Amur Outburst amplitude is 7m, if we believe in USNO-B1.0 magnitudes, and 6m (if USNO-A2.0 values are true): USNO-B1.0 1405-0020846 00 45 27.508 +50 32 15.56 pmRA=0 pmDE=0 B1=18.64 R1=19.27 B2=19.69 R2=19.95 I=19.30 USNO-A2.0 1350-00774528 00 45 27.52 +50 32 15.5 R=18.4 B=18.1 Color-combined DSS finder chart (10'x10' FOV): http://master.sai.msu.ru/static/OT/J004527+503213-BRIR.jpg MASTER-Amur discovery and reference images: http://master.sai.msu.ru/static/OT/004527.52503213.8.png This is the brightest northern CV discovered by MASTER-II robotic telescopes (the one at 12.1m in Lupus was found with MASTER-WFC in Argentina). Time-resolved photometry is strongly encouraged! Denis Denisenko Member of MASTER team at SAI MSU P.S. We were actually searching for the parent body of September Perseids which should be hiding in the Northern Milky Way now. ;-) No comet yet, but still a nice catch! ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Thu Sep 19 07:08:22 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 19 Sep 2013 07:08:22 -0400 Subject: (cba:news) Fwd: {SAS} 2014 Symposium Location and Dates In-Reply-To: <3AD497FF36E94107BB59B2CFCB64706B@VirtualXP30917> References: <3AD497FF36E94107BB59B2CFCB64706B@VirtualXP30917> Message-ID: <523ADB26.4050103@astro.columbia.edu> Dear CBAers, For those who didn't already get this (yesterday), here's the scoop concerning the 2014 SAS/AAVSO/CBA meeting. To my chagrin, they decided to move it from Big Bear - which I really liked - to Ontario, California, which is very near a moderately-big airport. So that'll bring some extra convenience, perhaps. I hope to induce a significant chunk of our non-Americans to attend and present results. And I can possibly help with (some) $$ support, airport pickups etc., and also organize some area sightseeing - including some of the usual LA stuff and maybe a climb of Mount Baldy (still probably a little snow-capped in early June). If you've never attended a SAS meeting (and even more if you have), these meetings are chock full of creative things people have done with telescopes and observations. And creative people of course. The internationals are (almost) always a hit with the audience; we norteamericanos are pretty familiar with what's happening in nearby backyards, and curious about what happens in distant ones, where the challenges are often quite different. Think about attending, and perhaps giving a paper. "Papers" can be oral or poster; strangely enough, they're not actually paper (until the proceedings are published). I'll discuss targets in a message later today. But in case I'm run over by a bus in the meantime (I cross Broadway twice a day, and every crossing brings a 10**-7 probability)... let's QUIT on V1101 Aql, and transfer all that wonderful effort to RX J2133.7+5107 ("Cyg" in the Downes catalog). This is a long Porb DQ Her star, in which Enrique has discovered a previously unknown signature of accretion disk precession (viz. its orbital sideband, or "negative superhump"). Because it's a long period, long runs are needed - common enough for us. But with long periods, calibration is more critical, since differential extinction can be problematic. To minimize that, I recommend using the same comparison star, and also listing the airmass if you can (so a rough extinction correction is possible). Enrique will follow up with more details, I think. I'm done with begging for V1494 Aql data; CBAers just don't like this star. So let's quit. But I'll start my begging earlier next year! -------- Original Message -------- Return-Path: After conducting a survey of the membership and past Symposium attendees, the SAS board has made its decision about the site and dates for the 2014 Symposium on Telescope Science: Location: Ontario, CA Dates: 2014 June 12-14 You can read more about the 2014 location, the reasons for the change, and the results of our survey by downloading a special edition of the SAS newsletter available via a link on our home page http://www.SocAstroSci.org/ or directly using http://www.socastrosci.org/images/SAS_Extra_2013Sept18.pdf Thank you to all who took part in the survey. We look forward to seeing you at next year's Symposium which will be a joint meeting involving SAS, AAVSO, and Center for Backyard Astrophyhsics (CBA). It's never too early to start thinking about the paper or poster that you'd like to present! Clear Skies, Brian D. Warner SAS Program Committee ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Mon Sep 30 23:01:11 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 30 Sep 2013 23:01:11 -0400 Subject: (cba:news) old and new targets, installment 1 Message-ID: <524A3AF7.4070202@astro.columbia.edu> Dear CBAers, I've mostly finished the analysis of this year's BW Scl data. Throughout the observing season, the star showed a not-quite-coherent-but-plenty-powerful signal at 17.3 c/d, together with its usual orbital signal at 18.41 c/d. The former differs from common superhumps because its period excess of 6.3% greatly exceeds the common-superhump excess of ~1.1%. And for another reason too: because it's a characteristic of *minimum* light, not maximum light. Only a few stars show this phenomenon, but they all seem to be pretty similar in their underlying structure: very low mass ratio, intrinsically faint, very rare eruptions (although the flagship of the class, WZ Sge, does not show the phenomenon). Anyway, Berto, Josch, Gordon, and Bob Rea have been observing the star assiduously, and we have an extraordinary long baseline over which to track the phenomenon. So it's enough! We're also through with PX And. This star is presently showing a positive superhump, as it did in our first campaign in 2000. However, it's quite a bit weaker this year - not promising for us to track accurately. Let's suspend for the year (at least). Likewise for OT J0045+50. Very nice star, but the outburst seems to be over. It's possible there will be some echoes. These are interesting... but not usually something *we* can learn much from, since time-series photometry during echoes usually shows waves of very small amplitude (if detectable at all). So I'd say we're through with this star. Likewise for V1494 Aql. We have the orbital light curve now to high precision... as well as for most previous years since the 1999 nova. Excellent material for a study of how the orbital light curves evolve. But we're done now. There are two evening stars for which we had very successful 2013 campaigns... and which we should now top off by revisiting for 7-10 more days. These are V1101 Aql and V1432 Aql. In both cases, we want to test for long-term coherence by counting cycles between observing seasons - so time series in late 2013 (now) and early 2014 (probably May) are the critical need. Have at it! Enrique has been managing RX2133+51 and ASASSN-13ck, so I'll let him comment on these. The former is certainly a very mysterious star. And now for NEW TARGETS, installment 1. We definitely want to launch campaigns on ES Cet and VZ Scl (assuming the latter is in its bright state at ~15.5). And two stars in the morning sky: LT Eri and "Tau2" (designation in the Downes catalog). We observed Mister Tau2 quite assiduously in 2002, and found something quite surprising: periodic signals seemingly at nu-orb, nu-orb+eps, and nu-orb-2eps. A bountiful harvest, since it would enable us to track the positive and negative superhumps simultaneously (which we have only done for one star). But the result was not quite 100% convincing... and for such a 100% interesting star, I needed to reach 100% confidence. We're a better network now - so let's do it. Installment 2 coming in a day or two. joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/