From jop at astro.columbia.edu Wed Jun 8 16:39:38 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 8 Jun 2005 16:39:38 -0400 (EDT) Subject: (cba:news) June stars Message-ID: Dear CBAers, Oops, it has been much too long! I've been hard at work on data analysis and writing up results for publication... and especially with V803 Cen (of which, more below). But time for an update on campaigns! I was very surprised to read in the last 2 days the news that Tom and Tonny had found superhumps in NSV 4838 = UMa 8... not because it's unlikely, but because it's so late in the season. Bravo! The only thing we can hope for is to use our longitude spread to count cycles (basically between Europe and the U.S... since we don't have any Asian observers), and get the superhump period. The runs will be too short to assemble long time series, but should be OK for time-of-maximum-light measurement. Since no one has ever managed to measure this before, it's well worth doing. The other prime northern (OK, equatorial) star these days is RX1730-05 = "Oph" in the Downes catalogue. This star, usually around V=15.5, has a 128 s period in its light curve, with substantial power also at 64 s. The orbital period is still not known. It should be red meat to us - assuming you keep accurate time! Awfully well placed in the night sky these days, too. Very, very nice challenge to CBAers of all conceivable longitudes and latitudes! There are competitor stars in the north and south. In the north, the main competition is "Her" = RX1643+34. We did very well on this star in the spring of '02, and published the results. There were some loose ends, and in particular the star shows the strongest persistent ~20 min quasi-periodic oscillations of any star in the sky. We've had it on the list for a while... but no groundswell of popularity has resulted. Nevertheless, it's a very deserving target! And in the south, it's still V803 Cen. As you might have noticed, Berto found the star breaking out a new supermax two days ago - and since then, Jennie McCormick and Bill Allen have obtained data from the other side of the Earth. And Paul Warhurst tells me he has obtained three nights of observation from Argentina. So we're doing pretty good. Still, June is a tad late for Centaurus, and it'll take some hard work to splice together a really good light curve. These outbursts are brief, so it's high time to get an intense few nights more of observation! joe From jop at astro.columbia.edu Sun Jun 12 12:49:02 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 12 Jun 2005 12:49:02 -0400 (EDT) Subject: (cba:news) 1600-48 Message-ID: Definitely worthy to study this newly discovered superhumper, as indicated by Berto! joe From jop at astro.columbia.edu Wed Jun 15 20:32:44 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 15 Jun 2005 20:32:44 -0400 (EDT) Subject: (cba:news) ASAS 1600-48 = Var Nor 05, our new friend Message-ID: Dear CBAers, I've just finished my first pass through the received data on this newly discovered dwarf nova. It has very, very powerful superhumps, well attested by the data from Berto, Chris Middleton, Grant Christie, and Peter Nelson. And the early coverage shows the growth of the superhump, a phase we seldom see at all. So we're poised for a very good campaign. In particular, it seems likely that with long time series from several sites around the world, we can detect the "orbital sidebands" in the superhump that cough up the coveted value of Porb. About half the time, the superhumps do that - but they *never* do it when the observational coverage is spotty. The V803 Cen campaign is near an end now - so I figured it's a good time to end the campaign and concentrate all that southern energy on our newly discovered friend. Long runs, fire away, and may a thousand stars decorate those long nights of yours. joe