From jop at astro.columbia.edu Tue May 11 17:30:19 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 11 May 2004 17:30:19 -0400 (EDT) Subject: (cba:news) Stars for May Message-ID: Dear CBAers, Time to replace the actors! The AM CVn campaign is ready to end. The 1028 s (orbital) is now well-timed for April-May, which stretches the baseline out to 14 years - and basically means that we don't need to visit the star for orbital period timings for another 5 years or so. There's another reason to keep going - the 1011 s signal which is flexing its muscles - but on balance I think it's time to say finis. The two good northern objects now are RX1643+34 (I dunno a proper name for it yet, but it's "Her" in CVCat) and V380 Oph. The former star was the subject of a great 2002 campaign (published in PASP) but needs another crack, to study the QPOs which were such a salient feature. It's about 12.7, very good for doing battle with the Moon. V380 Oph is fainter, about 14.6, with a Pspec but not much else known about it. It seems to have some sort of photometric wave of decent amplitude - in a few weeks we'll figger out what it is! I'm inclined to end V803 Cen too, with some trepidation. We've been going 40 days now, and for most of that time it's been in the "cycling state" with about a 23-hour quasiperiod. Excursions to the low or high state would be of great interest, and we can't be sure of catching 'em properly unless we keep looking... but meanwhile there are other fish to fry. I recommend switching off V803 Cen, except to check the brightness; if it jumps to 13.0 or 17.0, then it's time to jump back into action. I recommend replacing it with V2400 Oph - a moderately bright (14.7 or so) intermediate polar which has been very reticent in yielding its periods. With coverage in South Africa, New Zealand, Australia, and potentially Argentina (Paul Warhurst) we might finally crack this tough nut! joe From jop at astro.columbia.edu Sun May 16 22:01:15 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 16 May 2004 22:01:15 -0400 (EDT) Subject: (cba:news) erupting stars Message-ID: More stuff poppin' off up there... Patrick Woudt writes that "Hya" (the one at 0905-05, sometimes called SN 2003aw) is in outburst at 15th magntide. This is a terribly interesting object, perhaps the first superoutburst ever observed in it. Pretty lousy placement in the sky, but if we can patch together some observations from several longitudes, we can decipher the period structure. BR Lupi is also in superoutburst, and is an excellent target for long coverage by southern observers. Finally, please give V380 Oph an earnest effort. This seems to be a fascinating novalike with a complex period structure - bright, equatorial, well-placed in the sky. Got it all! joe