From jop at astro.columbia.edu Sat Oct 9 23:04:44 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 09 Oct 2010 23:04:44 -0400 Subject: (cba:news) a new stellar menu Message-ID: <4CB12D4C.1080303@astro.columbia.edu> Dear CBAers, The recent haul of data for program stars has been really great. It'll take me quite to assimilate it all... but I can see now that we've met objectives for XSS0056+45, V709 Cas, and IGR0023+61. All DQ Her stars that we want to revisit briefly *late* in the observing season (February?), in order to nail down cycle count. We have, however, secured the unique dividends that we get only from long time series. Exit left, to applause. In the evening sky, two DQ Hers that we still haven't got enough on are: RX2133+51 and V2306 Cyg. The latter, especially, is showing a complex multi-periodic structure I didn't expect; it may be too late in the season to decode this, but at a dec=+32 and multi-longitude observations, we might succeed. And an oddity in the evening sky. HR Lyr, a classical nova remnant which has been at ~15 for many decades. has apparently declined to 17th magnitude. A bit out of season... but cab someone find out what the light curve looks like in this strange - and unprecedented - state. And in the morning sky, I again urge coverage of RX0704+26 (Gem) and RX0636+35 (Aur). Especially the former, which may reward you with glorious light curves if you can manage a time resolution less than ~50 s. Now for dwarf novae. Many of you have contributed mightily to the campaign on SDSS0804+51 (Lyn). A very important star! (Probably a really ancient CV.) Question is: when to stop? It's still flashing echoes, but I suspect that time series during these echoes will not have much probative value. I could be wrong... but the humps decline to near zero amplitude at the tops of echoes - and the limited duration of runs is a big handicap. *Maybe* it has a week of life left in it, and maybe less. Just use your own intuition on this one - if the light curves still look good, then it's *certainly* worth continuing. One of the new CSS transients looks pretty interesting:, with about 2.2 hr superhumps: CSS 000938.3-121017 (chart and light curve on CSS website - which identifies the stars by *date* preceding the coords). Could be rewarding. V455 And remains good, and so does BW Scl. Still not much action on these this... but they're the New York Yankees of CVs. joe From jop at astro.columbia.edu Wed Oct 13 05:54:00 2010 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 13 Oct 2010 05:54:00 -0400 Subject: (cba:news) scratch RX 0704+26 Message-ID: <4CB581B8.3000101@astro.columbia.edu> Dear CBAers, Thanks to Tom and Bill Goff, the October 2010 pulse timings of RX0704 have nailed down the long-term pulse ephemeris, and I've completed our paper on this star. I'll send it out next week to collaborators (over the last 5 years: Mike Potter, David Boyd, George Roberts, Donn Starkey, Tut Campbell, and a few Columbias/Dartmouths). Great star, but we're done with it. A good time to work on other DQ Hers. (BTW, Koji Mukai's intermediate-polar webpage is information-central on these matters.) We're putting V709 Cas and XSS0056+45 on hold for a while, but excellent choices are V405 Aur (another big amplitude), RX0636+35, BG CMi, Swift 0732-13, V1062 Tau, MU Cam, HT Cam, PQ Gem (V filter only). This is in addition to not-yet-completed campaigns in the evening sky on AO Psc (easy), FO Aqr (easy), V2306 Cyg (hard), and RX2133+51 (hard). More than half of these stars have no published long-term period study, and NONE of them have such studies which are still valid today. Much to be learned from these stars, and because the periods are short, the information (pulse-timing) comes pretty fast. Also, unlike any other star we observe, observations early and late in the observing season have extra value, since they provide a lever-arm to determine cycle count between years. SDSS0804+51 continues to entertain with its echo outbursts... so cancel my dissing of this star. It's still awfully tough to decode this complex star, but it's a mighty important star. joe From demiguel at uhu.es Mon Oct 25 17:05:21 2010 From: demiguel at uhu.es (Enrique de Miguel Agustino) Date: Mon, 25 Oct 2010 23:05:21 +0200 Subject: (cba:news) V844 Her at supermaximum In-Reply-To: <293669.22139.qm@web25402.mail.ukl.yahoo.com> References: <293669.22139.qm@web25402.mail.ukl.yahoo.com> Message-ID: <579B7FE6-37FB-4B11-8735-37780597D3FC@uhu.es> Although V844 Her is low in the evening sky, I've managed to follow it for ~90 min. It's at 13.05V (mean value) and shows superhump-like modulations of ~0.15-0.18 mag, with a (crude) estimated periodicity of 0.0529 d. Regards, Enrique CBA Spain On 25 Oct 2010, at 16:49, Patrick Schmeer wrote: > Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany: > HERV844 20101022.765 127 SPK > HERV844 20101024.764 128 SPK > Sequence: AAVSO > Instrument: 203-mm SCT > > Regards, > Patrick > > > > ____________________________________________________________ > Center for Backyard Astrophysics (CBA) mailing lists > https://cbastro.org/communications/mailing-lists/