From jop at astro.columbia.edu Sun Jan 3 09:21:20 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 03 Jan 2010 09:21:20 -0500 Subject: (cba:news) January stars Message-ID: <4B40A7E0.8050208@astro.columbia.edu> Dear CBAers, Now that the Moon is safely (well, mostly) out of the way, here's a recommended menu for the next couple of weeks. First the north. Nights are long, and I really hope that the Euros will find some clear weather to extend our daily baseline on these guys. The star I'd like to promote most heavily is RX0704+26 ("Gem" in the Downes catalogue). This is a 480 s variable with practically all the power at 240 s, so the cycle time needs to be short - really no more than 60 s. At V=16.5, that might seem ambitious - but this star has a really, really large amplitude... and the observing issue is practically always time resolution, not signal-to-noise. I promise you - the light curve is gorgeous with good time resolution, and looks like a mess (though it isn't quite) if you don't resolve the pulse. (It turns out that the timing information is still decent if you don't... but better if you do.) With that RA and Dec, it's suitable for all-night coverage, and that would be scientifically very desirable as well. It's surprising that light curve evidence for Porb still eludes us - and I think it's because we still haven't had a concerted campaign. This is a DQ Her star (intermediate polar); we know the star's basic specs, but it cries out for a strong campaign - and now's the time. Early on in the night, XSS0056+45 is still a great choice. The spectrum of pulsations in this star (another DQ) is quite complex, and it'll probably require a multi-longitude campaign to resolve it with certainty. Same goes for a long period (something around 0.5-2.0 days, which the star seems to possess, but which is hard to study from one longitude.) Finally, AM CVn. Still quite early in the observing season, but we do need early-season timings to complement the dense March-April data I hope for. Plus the various DQs for which short observations (2-3 hours) would be fine: RX0636+35 = Aur, V405 Aur, MU Cam, HT Cam (kinda faint), DW Cnc. In the south, two stars for sure: WX Pyx, for which the earliest observations - mainly from Bob Rea - are showing a very high pulse amplitude this year. Great for most-of-the-night coverage. And T Pyx; I have that paper ready to go, but now that January has rolled around, I'd love to squeeze in one more observing season. Just a couple weeks would do the trick, since the cycle count issues are solved. Finally, YY Sex, preferably through an R or I filter (the amplitude is really high in the I band). A little early in the season, but should be feasible. I'm leaving for a meeting this morning, so will have somewhat crippled email access for a week. But I think I'll still be able to read it. Happy observing! joe the night, AM CVn is. That's the main troika I want to promote for northern observers. I'll cobble this together, add southern targets, and send out later today. joe From jop at astro.columbia.edu Thu Jan 7 09:47:18 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 7 Jan 2010 09:47:18 -0500 (EST) Subject: (cba:news) [Fwd: [baavss-alert] SDSS J073208.11+413008.7 and SDSS J230351.64+010651.0] Message-ID: ---------------------------- Original Message ---------------------------- Hi CBAers, I'm away at a conference and not able to look at Bill's data closely, but a glance at Bill Stein's light curves shows pretty obvious superhumps in SDSS 0732. Which is thereby confirmed as a SU UMa star. Another couple of nights should tune up the period (that is, the accuracy) nicely. I hope you can get it before the object fades from view! I also see that David Boyd has obtained some European coverage of RX 0704+26. I hope you guys can keep the coverage of that star intense until the Moon next invades Gemini. Thanks, Jeremy, for clueing me in on these eruptions. My access to email here (in Washington DC) has been sporadic... and I feel kind of disloyal being away when these time-critical campaigns are going on. But it's not like I'm enjoying a Bahamas holiday - it's minus 5 C outside! joe ubject: [baavss-alert] SDSS J073208.11+413008.7 and SDSS J230351.64+010651.0 From: "Jeremy Shears" Date: Mon, January 4, 2010 4:30 pm To: cvnet-outburst at yahoogroups.com "CBA-chat" baavss-alert at yahoogroups.com -------------------------------------------------------------------------- Both objects still in outburst: SDSS J073208.11+413008.7 Jan 4.870 15.9C SDSS J230351.64+010651.0 Jan 4.740 14.1C Jeremy Shears Cheshire, UK _________________________________________________________________ View your other email accounts from your Hotmail inbox. Add them now. http://clk.atdmt.com/UKM/go/186394592/direct/01/ [Non-text portions of this message have been removed] -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: untitled-[2] URL: From jop at astro.columbia.edu Sat Jan 9 11:12:58 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 09 Jan 2010 11:12:58 -0500 Subject: (cba:news) possible outburst of SDSS J225749.54-082228.7 Message-ID: <4B48AB0A.2030106@astro.columbia.edu> Hi CBAers, Gracious. Another strange one - possibly like KT Eri = Nova Eri 09. This one has a pretty good chance of being a dwarf nova, though. Let us know what you manage to learn about it. What's the rough color? Does it vary on a short timescale? - those might well be the strongest clues (with "blue" and "yes" being the choices indicating something like a DN). joe -------- Original Message -------- Subject: [vsnet-outburst 10891] possible outburst of SDSS J225749.54-082228.7: new CV or nova? Date: Sat, 9 Jan 2010 21:26:54 +0900 (JST) From: Hitoshi Yamaoka To: vsnet-outburst at ooruri.kusastro.kyoto-u.ac.jp CC: yamaoka at phys.kyushu-u.ac.jp Hi all, I have submitted the report below to the CBAT. -- Itagaki-san reported his detection of an apparent new stellar object (unfiltered mag 13.0) on Jan. 9.430 UT. He reported the position as R.A. = 22h57m49s.57, Decl. = -08d22'27".9. It should be an outburst of a star SDSS J225749.54-082228.7, which is tabled in some catalogs (USNO A2.0, USNO B1.0, GSC 2.3 and so on) as a star with mag about 20. Like as KT Eri, the amplitude of seven magnitudes is rather large for a dwarf nova, but somewhat small for a rapid classical nova. Cheers, Hitoshi Yamaoka, Kyushu Univ., Japan yamaoka at phys.kyushu-u.ac.jp <- changed! From jop at astro.columbia.edu Sun Jan 10 17:23:40 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 10 Jan 2010 17:23:40 -0500 Subject: (cba:news) stars for mid_january Message-ID: <4B4A536C.8060607@astro.columbia.edu> Dear CBAers, Time for some target changes. We've been conducting a long campaign on XSS0056+45, and by now all the periods (spin, orbit, various sidebands and harmonics) are well specified - and over a 54-day baseline. These periods will only slightly tune up from now on - so let's usher XSS off the stage. Likewise for RX0704+26. David Boyd sent a few nights of European data, breaking the alias, and steady coverage from Mike Potter, Bob Koff, and Tom Krajci has extended the baseline and enabled a cycle count going back to discovery 5 years ago. Even a comparison of X-ray and optical phases. So, again, all the period-finding is done... and, unless the star decides to erupt or fade or otherwise surprise, let's end the campaign. These winter campaigns on DQ Hers are going well; let's keep going! An evening pulse-timer target we haven't observed in several years is V709 Cas; it would be awfully good to get some late-season timings. The period is 312 seconds, so keep cycle times below ~80 s. The other stars are suitable for pulse-timing too, but their favorable placement in the sky makes them suitable for longer runs (which give better timings, and also can reveal other periods): these are HT Cam, Swift 0732-13, DW Cnc, and WX Pyx. All good targets. Plus EI UMa = PG0834+48; somehow we've never done a campaign on that one, but some fair evidence has emerged that suggests its identity as a DQ Her. Let's find out! Finally, there are the two AM CVn stars on our long-term list: ES Cet in the evening sky, and AM CVn in the morning. Not quite the right season, but good investments in the evening and morning. I'm back in NYC now, and good heavens, beginning a sabbatical! I should have much more time for science and CBA biz this year. joe From jop at astro.columbia.edu Sun Jan 10 17:41:13 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 10 Jan 2010 17:41:13 -0500 Subject: (cba:news) sdss0732+41 Message-ID: <4B4A5789.5070102@astro.columbia.edu> I forgot to mention this fine dwarf nova, which Bill Stein has been observing assiduously - with no help I believe - for the past week. This data shows not only the superhumps, but also the orbital period. (A rarity for noneclipsing dwarf novae in outburst.) A few more nights would tune up the periods... then the star can likely be thanked and shown the door. joe From jop at astro.columbia.edu Thu Jan 28 09:22:56 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 28 Jan 2010 09:22:56 -0500 Subject: (cba:news) U Sco in eruption Message-ID: <4B619DC0.9080306@astro.columbia.edu> Most or all of you know this... but it's a special opportunity for NZ/AU since they should have a little access to the star in the next few hours. The first day is the most critical! joe -------- Original Message -------- Subject: IAUC 9111: U Sco; V2673 Oph = N Oph 2010 [20409-2010/10-R1] Date: Thu, 28 Jan 2010 09:09:55 -0500 From: IAUC mailing list To: iauc at libraries.cul.columbia.edu Circular No. 9111 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS at CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT at CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html ISSN 0081-0304 Phone 617-495-7440/7244/7444 (for emergency use only) U SCORPII B. E. Schaefer, Louisiana State University, reports that B. G. Harris (New Smyrna Beach, FL, USA) has discovered the recurrent nova U Sco (cf. IAUC 7749, 8279) to be in outburst. On Jan. 28.4385 UT, U Sco was recorded with CCD images and visual observations to be at magnitude V = 8.05. This discovery has been confirmed by B. E. Schaefer with a 15.2-cm telescope and by S. Dvorak (Clermont, FL, USA) at mag about 8.8 visually. M. Templeton, AAVSO, reports the following previous magnitudes for U Sco: Jan. 27.450, V = 18.2 (Harris); 27.627, [16.5 (M. Linnolt, Hoolehua, HI, USA; visual). This is the tenth discovered eruption, with the last being in 1999 (cf. IAUC 7113), when it reached visual mag 7.5. U Sco is located at R.A. = 16h22m30s.80, Decl. = -17o52'43".0 (equinox 2000.0). The entire peak (from quiescence to peak, to one mag below peak) occurring inside of one day. This fast event requires fast reaction to get observations near the peak. V2673 OPHIUCHI = NOVA OPHIUCHI 2010 As first reported on CBETs 2128 and 2139 (where additional details may be found), S. Nakano, Sumoto, Japan, forwarded the discovery by H. Nishimura (Miyawaki, Kakegawa, Shizuoka-ken, Japan) of an apparent nova (mag 8.4) on frames taken on Jan. 15.857 UT with a Canon EOS 5D camera (+ Minolta 120-mm f/3.5 lens); Nakano measured mag 8.8 and the following position from the discovery image: R.A. = 17h39m40s.90, Decl. = -21o39'50".5 (equinox 2000.0). Additional CCD magnitudes: 2009 Nov. 3, [11.0 (Nishimura); 2010 Jan. 13.86, [9.5: (Nishimura); 14.865, 10.1 (Nishimura; measured by Nakano; limiting mag 10.6); 16.856, 8.4 (K. Itagaki, Takanezawa station, Tochigi-ken, Japan, 0.30-m reflector; position end figures 40s.94, 47".9); 16.860, 8.2 (K. Kadota, Ageo, Saitama-ken, Japan, 0.25-m reflector; position end figures 40s.97, 47".4); 18.299, 8.4 (W. Vollmann, Vienna, Austria, and H. Koberger, Vilaflor, Tenerife; green-band); 22.250, 9.5 (Vollmann and Koberger). Kadota adds that nothing is visible at this position on a red Digitized Sky Survey image from 1997 (limiting mag estimated to be 20 by Nakano). H. Maehara, Kwasan Observatory, Kyoto University, reports that a low- resolution spectrum (range 400-800 nm), obtained on Jan. 22.890 with a 25-cm telescope at Kwasan Observatory, shows H_alpha and Fe II emission lines and suggests that this object is a classical nova just after maximum. E. Kazarovets and N. Samus report that the GCVS designation V2673 Oph has been assigned to this nova. (C) Copyright 2010 CBAT 2010 January 28 (9111) Daniel W. E. Green _______________________________________________ iauc mailing list iauc at astro.columbia.edu https://mail.astro.columbia.edu/mailman/listinfo/iauc