From jop at astro.columbia.edu Mon Feb 15 16:34:05 2016 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 15 Feb 2016 16:34:05 -0500 Subject: (cba:news) february stars Message-ID: <56C2444D.9020303@astro.columbia.edu> Dear CBAers, Sorry about my (crazy) long silence. I've been engrossed in two big writing projects - a CV review paper and a history-of-astronomy book for the course I teach. Lots of progress, at least on the second, but I've left CBA biz sort of hanging as a result. Not re data analysis, but re communication! But I'm back in action now. Here are some stars which are ready to be taken off the menu: 1. T Pyx. Everything complete now, all the i's dotted and figures made. The 20-year study! I'm grateful to you australites who kept the faith this year; it nailed down the Porb change this season, and greatly strengthened the conclusion that Pdot after outburst = Pdot before outburst. No need for new data. 2. RW Tri. Absolutely great coverage, but the season has ended. Seemingly a discovery of a new very long period in RW Tri. 3. DW UMa. The season has barely begun, and it's one of our favorite stars. BUT David Boyd is on the verge of completing his write-up of a many-year campaign... and it may be time to take a rest. David, it's up to you. 4. BY Cam. Great campaign. I'm inclined to say "enough for the year", especially since there are many good evening stars in the north. And here are some new stars for the menu. 1. BH Lyn. Definitely. We had a good campaign a long time ago which showed superhumps, but the sign was undetermined because plausible positive and negative superhumps were (by chance) separated by 1 cycle/day. Bad luck! We have better longitude coverage now, and will resolve this ambiguity. 15th mag star, great northern target. 2. AT Cnc. Just getting to know this star, apparently a very old nova. Possibly a close cousin to V1101 Aql, which has been so good to us. 3. AM CVn. OK, not a very interesting star (14.2 all the time). But we're one season away from nailing down the Pdot of its orbital signal. We seem to be the only people who can measure it - it's just 1% - and it's our duty to do it! This is a helium CV; its main period is 525 s, but the orbital signal is at 1028 s. 4. V902 Mon. Really, really strange star. Eclipsing 8-hr guy. Practically all our data is from Enrique, so we don't have the advantage of longitude span. He'll keep going; it would be great to have help from AU/NZ and the Americas. 5. HZ Pup. Not new but I just wanted to beg a little harder for coverage of this "new" DQ Her star. In addition to the new ones, I wanted to beg again for coverage of some stars requested in December. I'll do that in the NEXT MESSAGE. And Enrique and David (Boyd), let your opinions be known! joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Mon Feb 15 18:07:35 2016 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 15 Feb 2016 18:07:35 -0500 Subject: (cba:news) Fwd: HZ Pup and friends In-Reply-To: <5662F228.5070600@astro.columbia.edu> References: <5662F228.5070600@astro.columbia.edu> Message-ID: <56C25A37.8050807@astro.columbia.edu> Dear CBAers, Here's the remnant from a December 2015 message, which remains timely (esp. HZ Pup). -------- Forwarded Message - But for this and future weeks, here's an appealing menu of new stars. 3. HZ Puppis (8 03 22.8 -28 28 28.8) = Nova Pup 1963. An obvious DQ Her system; we need another season to put it to rest. We need some early-season (now) and late-season (April) runs to establish precise cycle count... and a big push in Jan-Feb to parse the somewhat intricate period structure (sidebands, etc.) 4. Swift J0614+17 (=2MASS 06141230+1704321) (6 14 12.28 +17 04 32.6). Another new DQ Her, which is discussed in astro-ph 1510.00703 (Halpern & Thorstensen). V=17.5, but it's a healthy 23-minute signal. We've been sporadically tracking it, but now it's time to pick up the pace and establish a precise ephemeris. 5. Swift J0503-28 (5 03 49.25 -28 23 8.8) V=18.1, so this is ambitious. Another DQ with P = 16 min. 6. Swift J0525.6+2416 (5 25 22.75 +24 13 33.5) V=16.6 and P = 4 min. Anoter DQ Her star, keep the exposure short to resolve the pulse. BTW stars 4, 5, and 6 are ALL in the Halpern-Thorstensen paper described above: http://arxiv.org/abs/1510.00703 7. V902 Mon (6 27 46.4 +1 48 11). Eclipsing star, nature still unknown but likely to be a DQ Her or V Sge star. Doesn't nicely fit into any known category, though. NOTE: Except for (3), these stars are *slightly* out of season. Because most are DQs (=IPs), they don't necessarily need long runs - so consider 'em. (Although, admittedly, *all* CVs profit from long runs.) More DQ suggestions coming in a couple days. It sure is the season! Oh... and happy Galileo's birthday! joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/