From jop at astro.columbia.edu Sun May 5 07:07:55 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 05 May 2013 07:07:55 -0400 Subject: (cba:news) MASTER OT J094759.83+061044.4 - bright UGSU candidate, and other May stars In-Reply-To: References: Message-ID: <51863D8B.5050804@astro.columbia.edu> Dear CBAers, This looks like a good one for us - bright enough to follow for a while, and bright enough to eventually study (with big glass) the properties in quiescence. Not the best of sky positions, but we should be able to break aliases with a good longitude spread. And in the morning sky, I should - better late than never I guess - strongly endorse CSSJ174033.5+414756, another decently bright star (14?) showing 60 min superhumps. 60 minutes sort of makes you a law-breaker in the world of superhumps - too short for the usual family, and too long for the helium stars. There are excuses one can make for such oddities, but they're a tad strained. Let's observe the star heavily and figure it out! Here's the CSS link: http://nesssi.cacr.caltech.edu/catalina/20130418/1304181400734166981.html Then there's NR TrA, a "young old nova" - remnant of Nova TrA 2008. Fred Walter alerted me to this star, and Josch Hambsch has just finished a month-long time series on it, showing its 5.2 hour eclipses (or periodic dips, anyway). Although the data are substantial, they suffer from lack of longitude coverage (everything is from Chile) and also lack of time resolution. The star is easily bright enough to get some great data from South Africa and New Zealand. The field is kinda crowded, so study it first. I've about finished with that big Pdot study of DQ Hers, which I've been working on practically since the Chicago Cubs last won the World Series. One star of special importance is V1223 Sgr, which seemed to show steady period increase during 1981-2007. It's the only star doing that... and I want to bring it up to date in 2013. It's bright (13.5) and has a fast period (13.5 min, for that matter), so it should be easy. joe ---- Just published in ATel #5049, New Bright CV detected by MASTER MASTER OT J094759.83+061044.4 - new bright CV in Sextans 20130504.761 13.6CR MASTER-Kislovodsk 20130504.793 13.6CR MASTER-Kislovodsk Other IDs: SDSS J094759.82+061043.8 (u=20.04 g=20.42 r=20.19 i=20.27 z=20.26) http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237658424085053759 USNO-B1.0 0961-0183897 (09 47 59.811 +06 10 44.50 pmRA=-6 pmDE=18 B1=19.30 B2=20.33 R2=19.58 I=18.67) GALEX J094759.8+061044 (FUV=20.18+/-0.06, NUV=20.15+/-0.04) GALEX J094759.8+061043 (FUV=19.91+/-0.13, NUV=20.22+/-0.10) Two previous (but fainter) outbursts were detected by CSS on 2005 May 30 (15.8m) and 2006 Dec. 12 (15.3m). This variable is in Top 10 of brightest CVs discovered by MASTER. It is located well for the observers in both hemispheres, being an evening object. SDSS colors and outburst amplitude (~6m) definitely say in favour of SU UMa-type dwarf nova in superoutburst. Time-resolved photometry is strongly encouraged. Discovery and reference images by MASTER-Kislovodsk: http://master.sai.msu.ru/static/OT/094759.83061044.4.png Denis Denisenko Member of MASTER team at SAI MSU From jop at astro.columbia.edu Mon May 6 08:19:12 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 06 May 2013 08:19:12 -0400 Subject: (cba:news) SS UMi, YY Dra, YY Sex Message-ID: <51879FC0.20305@astro.columbia.edu> Hi CBAers, A few other stars to clarify their status. Enrique has started up the SS UMi season, and for northerners, strangely enough, the star is in excellent position for observation. The star is now around 17th and showing a strong periodic signal, and likely more than one. Just our cup o' tea... but we greatly need coverage at USA longitudes to unambiguously define the period structure. This star may give trouble since it's a frequent erupter... but I think it's probably interesting enough to declare all-out war (coverage at all luminosity states). But FOR SURE it's a great target at 17th magnitude - and get a LONG time series. Time to bury YY Sex. Very entertaining star, with huge humps, especially in I light. But the period is rock-stable, and there is no second period as asserted in the literature. Nor is it a reflection effect, as also stated in the only publication on the star. Just a garden-variety AM Herculis star. But we have some great data, and it'll be a cute little paper. Also time to bury YY Dra. The coverage, especially by Enrique, Jim Jones, and David Cejudo, has been good; but the detections of the fast period signals (9 and 4.5 minutes) have been *borderline*, and that's not sufficiently convincing when there are FOUR candidate signals (w, w-w_orb, 2w, 2w-2w_orb). Is anyone (in the CBA orbit) planning to go to the SAS conference in Big Bear this year? We usually go, but won't this year, mainly because of a Kitt Peak observing run coinciding exactly with the dates. The program seemed low on variable stars, and very low on CVs. We'll make a big push for next year, though. Meanwhile, is anyone planning to go? I'd like to announce here, to help you guys, if any, find each other. joe From jop at astro.columbia.edu Tue May 7 03:24:23 2013 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 07 May 2013 03:24:23 -0400 Subject: (cba:news) xmmu J1151-62 Message-ID: <5188AC27.6040901@astro.columbia.edu> Hi (southern) CBAers, Cancel the nightly coverage on this peculiar star - likely a nova in 2008 (though with most of its eruption probably occurring while hiding in the solar glare). We found a strong period of 0.3604 d in 2010, when the star was at V=13.9. Now it has faded by about 1 mag... and that signal (probably Porb) is gone. Much to my surprise and chagrin. One can dream up a scheme to explain it - decline of the supersoft source - but whether that's right or not, quien sabe? Anyway it's not a good target to pursue. It waffles around between 16.0 and 14.7, slowly and without a discernible pattern - despite good coverage from Josch and Berto. Not a winner. On to other stars! joe