From jop at astro.columbia.edu Fri Jul 5 08:17:58 2019 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 5 Jul 2019 08:17:58 -0400 Subject: (cba:news) HP Lib (only) Message-ID: <0e68280b-35e3-201d-e20d-69b025120b8a@astro.columbia.edu> Hi CBAers, The HP Lib campaign is almost finished. The main result has emerged: 0.08 mag superhump and 0.003 mag (peak-to-trough!) orbital signal, with the latter certified as orbital because of its high phase stability (over at least 4 years). And amazingly low erratic variability on long (night-to-night) and short ("flickering") timescales. A true twin of AM CVn in all these respects (and others). This was the most difficult measurement I have ever made. The sought-after signal is down by 30x in amplitude (and thus 900x in power) from the nearby superhump signal, which inevitably is surrounded by aliases. Often a long campaign ends on a note of "we'll do better next year". This time, it ended - or shortly will end - on a note of "Wow!" We need 2 more weeks to lengthen the baseline now, to connect to next February's time series, which will put the yearly cycle count beyond doubt (for that 2020 observation, we need only measure the *phase*, not an independent period). Right now there's an obvious best candidate for the precise period, but we'd like to upgrade from "best candidate" to "proven". So... two more weeks - and at lest two northerners (Tonny and Shawn D.) have successfully coped with the evening twilight and southern dec, and contributed important time series. So think about it. And for southerners: get thee to a telescope (although, granted, you already have; Berto, Gordon, and Josch get the Medal of Honor on this one). joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Fri Jul 5 16:57:54 2019 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 5 Jul 2019 16:57:54 -0400 Subject: (cba:news) July-August 2019 stars Message-ID: Hi CBAers, Here's an accounting of July-August stars, sorted by "program type". DQ HER STARS (intermediate polars). Many are in the sky now, and the world has issued us the task of keeping track of them. That means nightly 2-4 hour time series. In most cases the periods are already decently known; next up is to measure the period *changes* (and for those of you new to the CBA, that's been our job for years). In many cases, just *occasional* coverage is needed; no need to crazy on one star, unless you fine one you love - in which case, *definitely* go crazy on it! The stars in question are AO Psc, V1223 Sgr, V4743 Sgr, NY Lup, V2069 Cyg, V2306 Cyg. Leave DQ Her itself to Lew Cook; he's the master of that star. SUPERSOFT BINARIES. v617 Sgr, for sure. Maybe V Sge (excellent starter star, if you're altogether new to the CBA). Maybe IM Nor. RECENT NOVAE. v1494 Aql, V1974 Cyg, V4743 Sgr, NR TrA (faint). Maybe V1500 Cyg. Unlike the advice given for the DQ Her stars, these stars are generally best served by saturation coverage. Go "as long as you can, as often as you can". The DQs are different because their spin periods are *short* - they communicate a lot of information in just a few hours. MAXIE. The and only. MAXI J1820+070. The scattered reports now say V~18.6. Worth keeping an eye on. The star is full of surprises. That's the menu. Lotta stars getting into good shape for publication. Maxie, very soon. AM CVn, soon. HP Lib, maybe a hundred more hours of close study. joe AM CVN STARS. Just to finish up HP Lib. Can't recommend any others at this time. Most are very faint (19 or fainter). But I'll spend a few days stodying the roster. ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Fri Jul 5 17:02:41 2019 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 5 Jul 2019 17:02:41 -0400 Subject: (cba:news) V339 Del Message-ID: <07a54e88-df27-5295-9d02-d8d945083bdb@astro.columbia.edu> Hi CBAers, I forgot to mention the recent nova V339 Del. Good collection of data sent so far, but I haven't yet studied it enough to judge if it's a winner. I'd suggest suspending the campaign until further notice (that clarification will likely come within a few days). joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Sat Jul 13 14:56:59 2019 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 13 Jul 2019 14:56:59 -0400 Subject: (cba:news) Fwd: Re: Eruption of an 8th mag DN at 100 pc In-Reply-To: References: Message-ID: <505e9f6b-5bf5-fe4e-c448-f27d41b959aa@astro.columbia.edu> Hi (northern) CBAers, This looks like a great summer object for study! joe p, -------- Forwarded Message -------- Subject: Re: Eruption of an 8th mag DN at 100 pc Additional info: http://www.cbat.eps.harvard.edu/unconf/followups/J21040470+4631129.html Progenitor is 18th mag blue object! On 13/07/2019 17:42, Christian Knigge wrote: > In case you hadn't seen it yet > > https://www.aavso.org/tcp-j210404704631129-new-transient-92-mag-cygnus > > http://www.astronomerstelegram.org/?read=12936 > > I may be able to do something for this next week, but perhaps some of > you can react more quickly. I'd think anything would be useful -- > optical, UV, X-ray... > > Radio is already being asked for, I believe. > > C > > -- > -- =================================================== Professor Christian Knigge Physics & Astronomy University of Southampton Southampton SO17 1BJ ==================================================== ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/