From jk at cbastro.org Sun May 1 02:58:31 2011 From: jk at cbastro.org (Jonathan Kemp) Date: Sat, 30 Apr 2011 20:58:31 -1000 (HST) Subject: (cba:news) status update Message-ID: Hi, Briefly, core communications services should now be restored (pending some DNS information propagation). Web services will be restored in the near future as backups are restored. For those of you who would like additional detail, here's a bit more information. For many years we have have been thankful guests of our gracious host institution. However, we have had periodic network issues which were out of our hands, and also out of our host department's hands. This week's network issues were more problematic, so we accelerated existing plans to migrate elsewhere. That migration is approximately complete. Cheers, Jonathan From jop at astro.columbia.edu Sat May 14 09:24:47 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 14 May 2011 09:24:47 -0400 Subject: (cba:news) stars for May Message-ID: <4DCE829F.7020508@astro.columbia.edu> Dear CBAers, Apologies for my long silence. Just as T Pyx suddenly rose, I suddenly fell - with pneumonia. It didn't have any great complications, but kept me out of action for 6-7 weeks. I'm mostly OK now - and will see some of you at the AAVSO/AAS meeting in a week. Spending so much time at home, I've had the opportunity to analyze thoroughly the data from the 3 big springtime (northern) campaigns: ER UMa, BK Lyn, and AM CVn. ER UMa has proved to a pretty good clone of V503 Cyg, and suggests the hypothesis that all of these oddly-frantic and short-period dwarf novae may have "permanent" (i.e. not freshly reborn in superoutbursts) negative superhumps. Or, more expansively, that any short-period nonmagnetic star that is sufficiently bright for sufficiently long will have 'em. It's just a hypothesis, but so far there is no obvious counterexample. Questions remain: how bright? how long? and of course, whether this true. BK Lyn is certainly evidence for the prosecution, displaying simultaneous positive and negative superhumps. But these guys at RA=9 hr have had their say, so it's definitely time to end coverage of ER UMa and BK Lyn. AM CVn is a different story. So far we have excellent coverage over a 125-day season - the best ever. But the long and close coverage enables a study we've never been able to carry out for any star: tracking the small and simultaneous period changes in the negative and positive superhumps. Are they mirror images of each other? They ought to be, based on the simple hypothesis that they represent the natural apsidal and nodal precession of a disk of slightly varying effective radius. This study requires a lot of patience, because the period wiggles are quite small and slow; if we get as many as two complete up-and-down wiggles over a 5-month observing season, I'll be a happy camper! Can Ven is still around - so let's definitely keep going for another 3-4 weeks. A side benefit of AM CVn is the measurement of orbital period change. We've been keeping very close watch on Porb (1028.7322 s) since 1991... and since the weak orbital signal (0.007 mag) is heavily assaulted by the stronger superhump signals at 1011.43 and 525.56 s, it takes long time series to cleanly separate all these effects (and to build up the *significance* of the weakest signal). Another few weeks of coverage would add several new and valuable timings of orbital minima. So keep the faith! Josch, Enrique, Tom, Tut/George, and Shawn Dvorak have been the main players so far in the AM CVn story. I guess because of the southern Milky Way swinging into view, our southern menu is suddenly crowded! The following stars are now available, and are all subjects of our long-term period (and Pdot) studies: RX J1654-19* XMM 1151-62^ V4743 Sgr (too faint??) V617 Sgr^ WX Cen^ V1223 Sgr* GW Lib$ Swift 0732-13* T Pyx$ * means (mainly) rotational period study ^ means (mainly) orbital period study GW Lib and T Pyx are obvious choices (but their riches will be intellectual, not monetary). We're looking for GW Lib's post-eruption pulsation behavior - we found some quite fascinating behavior in 2010, and now it's time for an encore. At V=16, should be available to practically everyone. As for T Pyx, I was very surprised that our southern observers didn't jump all over it. I've not seen credible reports about periodic signals. But on the other hand, the periodic signal at quiescence was never - even to this day - seen by anyone else but us... so I conclude that it's basically OUR JOB to figure this out. So it would be a very, very good target for our southern observers for a few weeks. Sorry for the great brightness; it probably presents some challenges, but give it a try! Now for northern/equatorial targets. As some of you know, I've always been very interested in pulse-timing observations of the DQ Her stars (intermediate polars) early and late in the observing seasons. These are the key to precise many-year measurement of the periods - a responsibility which, as things have played out, has fallen entirely to us. The late-season guys are now: RX0704+26, RX0636+35, Swift 0732-13, and MU Cam; the early-season guys are V2306 Cyg, V2069 Cyg, FO Aqr, and AO Psc. A 2-3 hour observation of each usually produces a decent pulse timing... and a few such timings of each star, unless they disagree, usually suffices to nail down the all-important cycle count (to bridge between observing seasons). Lotta stars in this message! Pick out some which are well-placed for your aperture, latitude, observing style, etc. - and let the time-series rip. I hope to see a bunch of you in Boston next week. We'll certainly plan to go out for a CBA dinner together, possibly on Monday, May 23. joe From jk at cbastro.org Sun May 15 03:32:36 2011 From: jk at cbastro.org (Jonathan Kemp) Date: Sat, 14 May 2011 21:32:36 -1000 (HST) Subject: (cba:news) cbastro.org domain usage Message-ID: Hi, This is just a quick note to say that our recent server hosting transition means that any continued use of the old cbastro.org machine/domain will result in bounced mail since that machine no longer exists. Of course, cbastro.org continues to work just fine. While we transitioned to the new domain several years ago, there was no compelling reason at the time to advise people to stop using the old machine/domain as it was still functional, was hosting our new domain, and was then expected to continue to be functional. Of course, upstream network issues led to a service migration. So, just in case any of you are having mail issues and are using the older domain, updating your addressbook entries to use cbastro.org for chat posts, news posts, and data submissions is advised. Cheers, Jonathan PS - While some non-critical web services are still being restored as time permits, a provisional display of recently-submitted data is now available on the web site. From jop at astro.columbia.edu Fri May 20 10:58:36 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 20 May 2011 10:58:36 -0400 Subject: (cba:news) Fwd: [vsnet-outburst 12812] SDSS J220553.98+115553.7 outburst Message-ID: <4DD6819C.3010205@astro.columbia.edu> Dear CBAers, Not the greatest seasonal timing, but this could be a very rewarding star! First outburst ever observed. joe The Catalina Real-time Transient Survey detected an outburst of SDSS J220553.98+115553.7 (CSS110520:220554+115554). 1105201121174113562 2011-05-20T11:03:54 2011-05-20T10:59:25 22 05 53.98 +11 55 53.8 14.46 14.46 n/a 14.34 http://nesssi.cacr.caltech.edu/catalina/20110520/1105201121174113562.html This object has an orbital period of 82.825 min (Southworth et al. 2008, MNRAS, 388, 709). The object is a good candidate for an SU UMa (or WZ Sge) type dwarf nova. Follow-up observations are encouraged. From jop at astro.columbia.edu Wed May 25 08:36:06 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 25 May 2011 08:36:06 -0400 (EDT) Subject: (cba:news) [Fwd: [vsnet-alert 13342] Re: OT J210950.5+134840 = Itagaki transient] Message-ID: <63a6c88e381c1f6353d182248c8b8c97.squirrel@webmail.astro.columbia.edu> Definitely, a GREAT object for CBA time-series coverage!!! joe ---------------------------- Original Message ---------------------------- Subject: [vsnet-alert 13342] Re: OT J210950.5+134840 = Itagaki transient From: "Korotkiy Stas" Date: Wed, May 25, 2011 4:07 am To: vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp -------------------------------------------------------------------------- 1909-08-15 >15.2mag (HDAP) 1909-08-15 >15.2mag (HDAP) 1912-09-09 >13.2mag (HDAP) 1913-07-31 >14.5mag (HDAP) 1951-07-30 ~18mag (DSS) 1991-07-16 ~18mag (DSS) 1992-10-16 ~18mag (DSS) 1995-07-21 ~18mag (DSS) 1998-09-21 >14mag (2MASS) 2000-06-16 - 2005-08-15 ~18mag (NEAT) Stas Korotkiy, Moscow 25.05.2011, 08:16, "Taichi Kato" : > OT J210950.5+134840 = Itagaki transient > > ???Itagaki-san has detected a likely dwarf nova in outburst. > The object was at 11.5C mag on May 24.6991 UT. > The amplitude of the outburst is larger than 7 mag, and it is likely > a WZ Sge-type outburst. ?Time-resolved photometry and spectroscopy > are encouraged! > > http://www.cbat.eps.harvard.edu/unconf/followups/J21095047+1348396.html From jop at astro.columbia.edu Wed May 25 08:39:12 2011 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 25 May 2011 08:39:12 -0400 (EDT) Subject: (cba:news) [Fwd: [vsnet-alert 13344] Re: OT J210950.5+134840 = Itagaki transient] Message-ID: <52deef0dbb2885a1dd7cfa6fc5b5df08.squirrel@webmail.astro.columbia.edu> More useful info on this eruptive star. Remember, the contaminating star will be of no importance whatever as long as the eruptive star remains bright. Good luck! joe ---------------------------- Original Message ---------------------------- Subject: [vsnet-alert 13344] Re: OT J210950.5+134840 = Itagaki transient From: "walcom77" Date: Wed, May 25, 2011 6:16 am To: "Denis Denisenko" "arne" planet171 at yandex.ru Cc: vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp -------------------------------------------------------------------------- Following the posting on the Central Bureau's Transient Object Confirmation Page about the transient in Peg we performed some follow-up of this object remotely through a 0.25-m, f/3,4 reflector + CCD, from GRAS Observatory (near Mayhill, NM). On our images taken on May 25.3, 2011 we can confirm the presence of an optical counterpart with unfiltered CCD magnitude about 11.0 (USNO-B1.0 Catalogue reference stars) at coordinates: R.A. = 21 09 50.46, Decl.= +13 48 39.6 (equinox 2000.0; USNO-B1.0 catalogue reference stars). According to VIZIER there is a 18.82 R2 magnitude star at 0.0099 arcmin from the transient position (USNO- B1.0 1038-0586809). Our confirming image of this transient and an animation showing a comparison between our image and the archive POSS2/UKSTU plate (R Filter - 1991): http://bit.ly/mycwOt With kind regards, Ernesto Guido and Giovanni Sostero http://remanzacco.blogspot.com http://twitter.com/comets77