From jop at astro.columbia.edu Sun May 2 22:11:59 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 02 May 2010 22:11:59 -0400 Subject: (cba:news) stars for early May Message-ID: <4BDE30EF.7010700@astro.columbia.edu> An embedded and charset-unspecified text was scrubbed... Name: cba5210 URL: From jop at astro.columbia.edu Tue May 4 03:55:33 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 04 May 2010 03:55:33 -0400 Subject: (cba:news) CR Boo and ASAS J1536-0839 Message-ID: <4BDFD2F5.9020503@astro.columbia.edu> Dear CBAers, I've heard now from Enrique de Miguel Agostino and John Thorstensen regarding these stars. ASAS 1536 ("Lib") is about 18.4, and unless you're distinctly enamored of working on such faint stars (some people are), I'd advise you to take that one off the list. On the other hand, Enrique estimates "fainter than 17.0" for CR Boo - and for us, that really vaults the star in priority. We've observed CR Boo for hundreds of nights, and only found it faint (~17.5) once... and when we did, it showed a really strange spectrum. I've been craving for this opportunity since 1996. Also, give the star now a high priority after it leaves the low state (sadly, that'll probably be quite soon); exactly how the star enters and leaves the low state - relative to its normal state of rapid cycling, for example - is unknown. Because past observations suggest a cycling quasiperiod around 19 hours, the star will GREATLY repay multi-longitude observation. With an equatorial location and the star now transiting near local midnight, this is likely to be a great observing opportunity. 17.5 might well be too ambitious, and if so, have a high old time with HP Lib - a close relative, quite bright, and pretty interesting too. But we'd sure love to indulge this craving for CR Boo in quiescence! joe John, I know yer out there with a spectrograph and a big telescope... and it's near local midnight. And reading email at this exact moment. I fling down the gauntlet. From jop at astro.columbia.edu Fri May 7 09:52:34 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 07 May 2010 09:52:34 -0400 Subject: (cba:news) CR Boo at or near quiescence Message-ID: <4BE41B22.7060101@astro.columbia.edu> Dear CBAers, The first few runs on CR Boo, all on that first day, were great - with a strong 25 minute signal and a likely fast pulsation. Around magnitude 17.3. In the two following days, the star resumed its perplexing rapid up-and-down ramps - only this time between 16 and 17.3, not between 14.5 and 15.5 as is its more normal practice. I now think it was a mistake to call off the earlier campaign. These ramps are irritating, if what you really want is quiescence. But since it's near quiescence, the star could well be just settling sporadically into it... and also, if we're decent scientists, we should welcome the challenge to understanding, rather than just be irritated... right? right? So let's catapult CR Boo back into a top-priority target! BTW try for cycle times (integration + readout) of less than 2 minutes. It's faint, but a good candidate for rapid pulsations (hence the need to resolve 'em). With the SAS conference looming at Big Bear, some of our big guns - especially in the western USA - will be out of action for a while. I hope the rest of you will jump into the fray! joe From jop at astro.columbia.edu Sat May 8 15:59:33 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 08 May 2010 15:59:33 -0400 Subject: (cba:news) FW: AAVSO Special Notice #208: Optical transient in Pegasus] Message-ID: <4BE5C2A5.7070001@astro.columbia.edu> Dear CBAers, This is potentially a SENSATIONAL object, if it is a dwarf nova, not a classical. Probably pretty damn interesting if it's some third class of object, too. Anything that erupts violently to 8th magnitude frantically deserves our attention... and in particular OUR attention. You might have to do aperture photometry to include both stars in the double. I'd consider that the safe approach, although if you're well acquainted with your local capabilities re psf fitting, telescope drive, etc., make your own judgment. Also check all available news sources for the doubtless rapidly evolving information on this star. Could this be a true challenger to WZ Sagittae's supremacy? GW Lib and V455 And were mighty impressive, but fell somewhat short. The heart starts to beat faster... joe Great follow-on to CR Boo in the night-time sky. BTW I hope that southerners will consider this target, too. +21 doesn't look good, but the nights are long, so maybe? Subject: AAVSO Special Notice #208: Optical transient in Pegasus AAVSO Special Notice #208 Optical transient in Pegasus May 8, 2010 CBET 2273 (D.W.E. Green, editor) reports the discovery of a bright transient in Pegasus by Dae-Am Yi (Yeongwol-kun, Gangwon-do, Korea). The object was discovered at magnitude 10.8 on 2010 May 6.77 (JD 2455323.27) on an image taken with a Canon 5D + 93-mm camera lens. The object brightened to magnitude 8.4 as observed on 2010 May 7.76 (2455324.26) on an image taken with a 400-mm lens. The transient object appears to be concident with GSC 2197:886 on discovery images, but this identification is not yet proven. The GSC star has a NOMAD catalog V magnitude of 13.84 and is a close double with a separation of about 3 arcseconds. Based upon an examination of the POSS-I and POSS-II plates by Arne Henden, it is possible that the double is composed of two unassociated stars, one with a high proper motion. Observations of this field are strongly encouraged both to obtain astrometry of the source and to follow the progress of this outburst. It was noted by H. Yamaoka (Kyushu University) that there is a bright ROSAT X-ray source within seven arcseconds of the GSC star, and so the object may be a cataclysmic variable of some kind. CBET 2273 gives the coordinates of the GSC star for the object, which are RA: 21 38 06.571 , Dec: +26 19 57.33 Charts for this object may be plotted using AAVSO VSP: http://www.aavso.org/observing/charts/vsp/index.html?pickname=VSX%20J213806. 5%2B261957 Please promptly submit all observations to the AAVSO using the name "VSX J213806.5+261957". This AAVSO Special Notice was prepared by M. Templeton. --------------------------------------------------- SUBMIT OBSERVATIONS TO THE AAVSO Information on submitting observations to the AAVSO may be found at: http://www.aavso.org/observing/submit/ SPECIAL NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION A Special Notice archive is available at the following URL: http://www.aavso.org/publications/specialnotice/ Subscribing and Unsubscribing may be done at the following URL: http://www.aavso.org/publications/email/ From jop at astro.columbia.edu Sat May 8 16:19:33 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 08 May 2010 16:19:33 -0400 Subject: (cba:news) [Fwd: CBET 2275: 20100508 : CATACLYSMIC VARIABLE IN PEGASUS] Message-ID: <4BE5C755.70707@astro.columbia.edu> Here's a lot more info on this fascinating star. So far, the magnitudes, spectrum, and proper motion are all highly consistent with the WZ Sge class - indeed, a quite good match (so far) with the great WZ itself. Drag the telescope into that morning chill, and watch those beautiful light curves come rolling out of your cameras! And let us know what you find! This message contains, among other goodies, the exact positional information. If you have a V filter, that would be a good choice. R is good, too. The star is bright enough (and probably will remain so) to survive filtering, plus the obvious advantages: standardization, better control of extinction, etc. However, eventually we're going to have to all convert to unfiltered (to get good signal-to-noise late in the outburst)... and *some* unfiltered observation now will help make this transition more tractable. joe -------- Original Message -------- Subject: CBET 2275: 20100508 : CATACLYSMIC VARIABLE IN PEGASUS Date: Sat, 8 May 2010 14:55:30 -0400 (EDT) From: quai at cfa.harvard.edu To: IAUC at libraries.cul.columbia.edu Electronic Telegram No. 2275 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbat at iau.org; cbatiau at eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html CATACLYSMIC VARIABLE IN PEGASUS [Editor's note: the following text replaces that on CBET 2274] S. Nakano, Sumoto, Japan, reports the independent discovery of the outburst of this variable (cf. CBET 2273) by Shizuo Kaneko (Kami-Yashiki, Kakegawa, Shizuoka-ken) at mag 9.0 on two 20-s exposures (limiting mag 12.4) taken on May 7.787 UT with a Contax 80-mm f/2.0 camera lens (+ Canon Kiss Digital X camera); nothing was visible at this position on a frame taken by Kaneko on May 1.742 with the same instrumentation. From Kaneko's discovery frame, Nakano measures mag 9.1 (limiting mag 13.2) and the following position for the variable: R.A. = 21h38m07s.03, Decl. = +26d20'03".0 (equinox 2000.0; probable error +/- 4"), adding that a faint star of mag around 14 is visible at position end figures 11s.5, 01". H. Yamaoka, Kyushu University, reports that the variable appears at mag about 15 (near the limiting magnitude) on a CCD survey image taken by K. Itagaki (Yamagata, Japan) on May 1.71 UT with a 0.21-m telescope, which suggests that the star was then at a quiesient phase; Itagaki provides position end figures 06s.66, 19'57".1 and mag about 8.8 from an image taken on May 8.657 UT with his 0.60-m telescope, indicating that the outbursting object is a southern component of a double star GSC 2197:866 (cf. CBET 2273). A. Henden, AAVSO, notes that Palomar Sky Survey (POSS) plates show a close pair of objects at the location of the outbursting variable: one is essentially stationary, while the other has a relatively high proper motion. On the POSS-I plates, the southwest component of the 3"-separated double is obviously blue, while on the POSS-II plates, it has moved east-northeast by about 3" and is now about 1" southeast of the stationary northeast component. At this motion rate, it would be expected to lie an arcsec or two east of the stationary component at this epoch. This rate of motion would imply something intrinsically faint but relatively close; adding in the color would imply a white dwarf -- suggesting that the moving object is the outbursting object and that it is a cataclysmic variable with an amplitude of about 6 magnitudes. P. Camilleri, Sydney, Australia, obtained two unfiltered CCD images of the variable remotely at the Tzec Maun Observatory in New Mexico using a Takahashi Epsilon 0.18-m f/2.8 corrected Newtonian reflector (May 8.371 UT, mag 9.3) and a 0.35-m Maksutov-Newtonian f/3.8 reflector (May 8.388, mag 8.9), yielding position end figures 06s.64 +/- 0s.02, 19'56".8 +/- 0".1. Tabulated summary of the available data from CBET 2273 and above: 2010 UT R.A. (2000.0) Decl. Mag. Observer May 1.71 15 : Itagaki 1.742 [13 : Kaneko (Nakano) 6.77 (21 38 06.6 +26 19 57) 10.8 Yi 7.76 8.4 Yi 7.787 21 38 07.03 +26 20 03.0 9.1 Kaneko (Nakano) 8.371 21 38 06.63 +26 19 56.7 9.3 Camilleri 8.388 21 38 06.66 +26 19 56.8 8.9 Camilleri 8.657 21 38 06.66 +26 19 57.1 8.8 Itagaki M. L. Graham, H. Broekhoven-Fiene, A. H. Parker, S. Sadavoy, and A. J. Maxwell, Department of Physics and Astronomy, University of Victoria; E. Y. Hsiao, Lawrence Berkeley Laboratory; and D. D. Balam, Dominion Astrophysical Observatory, National Research Council of Canada, report that a spectrum (range 390-703 nm, resolution 0.3 nm) of this variable (cf. CBET 2273), obtained on May 8.47 UT with the 1.82-m Plaskett Telescope of the National Research Council of Canada, shows strong H-alpha and H-beta in emission (HWFM 800 km/s), as well as He II (468.6 nm) and a broad emission feature centered at 465 nm that is interpreted as the Bowen complex of N III, C III, and C IV. All members of the Balmer series show shell-like profiles with both red and blue absorption components. A. Arai, Kyoto Sangyo University, reports that an optical spectrogram (resolution 500) of the variable was obtained using the 1.3-m ARAKI telescope on May 8.66 UT under poor sky conditions. The spectrum shows a blue continuum and a weak H-alpha emission line (EW about 0.4 nm), suggesting that the object would be classified as a dwarf nova. No other significant emission or absorption lines were seen in the low-S/N data. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 May 8 (CBET 2275) Daniel W. E. Green _______________________________________________ iauc mailing list iauc at astro.columbia.edu https://mail.astro.columbia.edu/mailman/listinfo/iauc From jop at astro.columbia.edu Sat May 8 23:26:25 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 08 May 2010 23:26:25 -0400 Subject: (cba:news) v893 sco, V803 Cen, and the new dwarf nova Message-ID: <4BE62B61.8080804@astro.columbia.edu> Lotta new stuff in the sky! I hope that people will send in their OT2138+26 plans (as well as observations of course). It'll help me a lot; we're on the 1.3 m telescope, vast overkill of course for an 8th magnitude star... and I'd breathe a lot easier if I knew that the star was being well covered now by several USA (and subsequently NZ/AU) observers. Then we can go back to our little 20th magnitude white dwarfs. Rod Stubbings alerts to two important events in the southern sky - a large brightening, possibly a superoutburst, in V893 Sco, the famous eclipser. And a low state in V803 Cen - also quite rare, as true for CR Boo. (These are both members of the very select class of pure helium CVs.) Both awfully well-placed in the May sky. Not a good week for having conferences, when astronomers are exiled from their toys. You non-conference-goers out there, take up the challenge! joe From jop at astro.columbia.edu Mon May 17 22:12:20 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 17 May 2010 22:12:20 -0400 Subject: (cba:news) VSX J213806.5+261957 (OT in Pegasus) Message-ID: <4BF1F784.1080601@astro.columbia.edu> Dear CBAers, Just back from the SAS meeting, which was very solid, dazzling in spots. It always leaves me with the feeling "We better raise our game to keep market share!" Next June we (the CBA) would like to have a little side meeting at the June AAS meeting in Boston - and hope this will draw some European attendance. Only Enrique de Miguel (Huelva Spain) represented the Euros this time around. OT 2138+26 has done everything we'd hoped - it's really and truly a large-amplitude nearby dwarf nova, likely of very long recurrence period (close cousin to WZ Sagittae). Its location in Pegasus is no picnic in May... but I really, really hope you guys can get maximally long light curves, and I *really* hope for non-American coverage, so we can solve the alias issues which otherwise might bedevil us. So far, Tom Krajci, Bill Stein, and Gordon Myers have been holding down the fort. As Tom's reports show, the superhumps are booming - so let 'er rip. Earlier in the night, CR Boo, V893 Sco, and HP Lib remain attractive targets. CR Boo is certainly in an odd state - it would be great to have multi-longitude observations of it, so we can assess these long ramps in light for which it is somewhat famous. I'm actually still at Kitt Peak, trying to observe 19.5 mag white dwarfs through clouds (and computers filled with mouse droppings). Not a good combination. I get home late tomorrow, and leave everything to Helena Uthas, who many of you met at Big Bear, and who will be postdocking in CVs at Columbia starting December. Happy observing! joe From jop at astro.columbia.edu Sat May 22 00:58:40 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 22 May 2010 00:58:40 -0400 Subject: (cba:news) GW Lib, SDSS1339+48, V4743 Sgr, and OT2138+26 Message-ID: <4BF76480.7080206@astro.columbia.edu> Dear CBAers, Time for some spring cleaning. Unless it goes steadily faint again, we can leave CR Boo for the season. The campaign on OT2138+26 is going well (good coverage from Bill Stein, Tom, Bill Goff, and Enrique)), but the unfavorable placement of Pegasus in May creates problems. We *really* could use some coverage from other longitudes - while hanging onto our existing ones! Helena (Uthas) is still at Kitt Peak, along with several Columbia students, and is carrying out a campaign on a CV with a pulsating white dwarf: SDSS1339+48 ("UMa" in Downes catalog). I would *love* to get some CBA coverage on this star. It has a very long period ("superorbital"), which probably will require multi-longitude observation to break the alias. In addition, the pulsations are probably stable enough to reveal fine-structure effects (beating of closely spaced signals, etc.) if we could get such data. I think that at least some CBAers can get good data on this 17.5 mag star - the light curve will be no beauty, but the power spectrum should show the pulsations. We especially want European coverage, of course! Let's see if Arto or Enrique rise to the challenge. I admit the waxing Moon is no friend to this enterprise. But periodic signals have a way of shining through... and anyway, our interest in this star will go on at least a few weeks. In the same vein, we're also campaigning on GW Lib, brighter at 16.5. Clobbered by the Moon on certain nights because of its zodiacal location, but happily southern and brighter. An excellent target for southern telescopes, for two reasons: the pulsations, and the mysterious "2.1 hour" signal of unknown origin. Our previous campaign showed that it's actually a 4.2 hour signal (with most power at the first harmonic)... now we want to go on it a while to test for stability. These mysterious superorbital periods are still a total mystery in CVs (about 10 of them). Finally there's V4743 Sgr. We need one more season on this, or possibly just one more month, to complete our study over an 8-year baseline. It's back - I hope some southerners can help us wrap this one up. If you'd like to receive any of our data on these various targets, please ask! We don't yet have any automatic system for this, but are developing one. In the meantime, try the old-fashioned way! joe From jop at astro.columbia.edu Sat May 22 15:22:37 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 22 May 2010 15:22:37 -0400 Subject: (cba:news) [Fwd: [vsnet-alert 11996] EX Hya outburst!!] Message-ID: <4BF82EFD.1060600@astro.columbia.edu> Holy mackerel! Not a bad time of year either. Speaks for itself: great, great opportunity... and after it subsides, too. These eruptions are very rare, and mostly (or perhaps always) quite short. Not much has been done re time-series photometry of the outbursting EX Hya - time to change that! joe -------- Original Message -------- Subject: [vsnet-alert 11996] EX Hya outburst!! Date: Sun, 23 May 2010 04:57:54 +1000 From: Rod Stubbings To: EX Hya is in outburst. EX Hya showed some marked variations leading up to this outburst. HYAEX 100521.653 129 HYAEX 100522.667 94 HYAEX 100522.686 94 HYAEX 100522.721 94 Regards, Rod Stubbings 20100508.374 137 20100508.601 129 20100509.596 131 20100510.574 124 20100510.603 131 20100516.383 131 20100516.485 124 20100516.587 129 From jop at astro.columbia.edu Sun May 23 07:11:09 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 23 May 2010 07:11:09 -0400 Subject: (cba:news) EX Hya so far Message-ID: <4BF90D4D.5050005@astro.columbia.edu> Dear CBAers, Here's the first night's light curve (V-C), observed by Berto, Tom, and Bill Stein. The star declined by ~1 mag between day 1 and 2, as (somewhat) expected from past outbursts. So far, results from the interocular trauma test ("does anything smack you between the eyeballs?") are negative. Borealites, forget not about SDSS1339+48... if you can tolerate the Moon. joe -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: ex339 URL: From jop at astro.columbia.edu Sat May 29 23:34:14 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 29 May 2010 23:34:14 -0400 Subject: (cba:news) may-june targets Message-ID: <4C01DCB6.2020801@astro.columbia.edu> Dear CBAers, Well, EX Hya went like a tornado, as is its wont. And V1032 Oph has long since faded. And it's time to draw the curtain on CR Boo. So let's switch to a new menu for June. The erupting and eclipsing dwarf nova in Lynx ("Lyn" in Downes catalog, or SDSS0903+33) would be a great target for about one more week. Enrique de Miguel has been fighting alone on this one; he has found excellent superhumps - now we need some USA coverage to nail down the period precisely! Not in the sky long - you can close the telescope in time for the late news! The new dwarf nova in Pegasus (OT2138) will remain interesting as long as it's bright enough to observe. Not very well placed of course... and of course the undesired companion star will get annoying as the star fades. But we manage to do OK with splices from Spain and New Mexico, among others. So we're managing to keep decent track of the evolving outburst. Lots of room for improvement there! I've received several runs now on SDSS1339+48, a CV with a pulsating white dwarf. To my delight, Bill Goff is able to detect these pulsations with a 14-inch telescope - even with a dead-full moon in the sky! So we can find 2% signals on V=17.5 stars in full moon - verry, verry nice. This star is worth tracking a few weeks, or until it proves/disproves its basic coherence. An even better target of the same ilk is GW Lib, and I really HOPE that some North American observers - as well as our usual stalwarts in ZA/AU/NZ - can contribute to this star's record. I promise to analyze the data immediately and comment. The pulsations may or may not be present, but the other main target is the 2.1/4.2 hr variation that has become slightly famous - and remains unexplained. So far, no takers on V4743 Sgr. We have quite good coverage on it through last year - just need a few more timings to conclude the study. Well placed for you australites. The bright northern target this season is V1084 Her (= "Her" in Downes catalog). We started it last month, then the dwarf novae started popping off. Time to go back into the water. Also, a target I highly recommend in the post-midnight sky is GD 552 (= Cep 1). I'd love to start the GD 552 season about now (and Helena will get 1-2 runs with the 2.4 m). Buena suerte! joe Finally, there's GD 552 = Cep 1. Available to northerners after 1 a.m. Let's begin the GD 552 observing season! From jop at astro.columbia.edu Sun May 30 00:27:41 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 30 May 2010 00:27:41 -0400 Subject: (cba:news) and one more: RX1654-19 Message-ID: <4C01E93D.3000603@astro.columbia.edu> Oops, I forgot our shiny new intermediate polar in Ophiuchus - from Christian Knigge and Helena Uthas. Our observing run is practically over, but this is a great star to continue covering from CBA telescopes. RX 1654-19 About 15.6, I believe. Very handsome light curve. 16 54 43.73 -19 16 30.7 joe -------------- next part -------------- A non-text attachment was scrubbed... Name: rx1654.jpg Type: image/jpeg Size: 120623 bytes Desc: not available URL: