From jop at astro.columbia.edu Thu Jul 30 09:01:50 2020 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 30 Jul 2020 09:01:50 -0400 Subject: (cba:news) august stars Message-ID: Hi CBAers, 1. In recent years we've been accumulating a lot of data on "old novae", including some that are not so old, plus otherl which are related to old novae (which could be suspects from the pre-temescopic age, or which probably burn hydrogen stably rather than explosively). It's time to bring some of these studies to print... and therefore to get a good final season, the better to nail down - typically - the orbital waveform and period change. These are NR TrA, V4743 Sgr, Nova Sco 1437, V Sge (bright!), V617 Sgr, and QR And. All new objects for this season, but friends of ours from past years. None are *fast* variables, so you can just pick a time resolution you're comfortable with. Howeve, since the period of interest is ORBITAL, the observation should be long (at least 3 hours) V1494 Aql and V1974 Cyg are entitled to be on this list. But V1494 has been well taken care of this year, and the signal in V1974 is hard to spot. So I'm taking them off. 2. Intermediate polars (DQ Her stars). Right up our alley to measure period change, since we have baselines of 5-20 years. The ones needing just occasional observation are FQ Aqr and AO Psc. V1223 is more interesting since it has been much more active this year, and a still-unsettled question is the connection between brightness and period change. It will take some patience to settle this. Then there are IPs that we have observed frequentlybut never quite published our results. A good season on these will push us to completion! These are V515 And, V1033 Cas, V2069 Cyg*, V2306 Cyg*, and V598 Peg. The asterisk here means "we have a lot this year, but should take it to the end of the observing season, in order to secure a correct cycle count from one year to the next (or the previous).". 3. The asynchronous polars. The good ones this season are CD Ind and V1432 Aql. Need longish runs. 4. It's usually a good idea to find a good target, well placed in the sky, and stick with it. But that's less true for the IPs, where early- and late-season observations can be critical in specifically long-term cycle count. I have at least the next semester off from teaching, and expect to bring a number of these studies to completion! joe p p.s. don't overlook N Sco 1437 - A really spectacular light curve! haven't made its acquaintance, A spectacular light curve ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/