From jop at astro.columbia.edu Thu Mar 17 14:40:34 2022 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 17 Mar 2022 14:40:34 -0400 Subject: (cba:news) stars for march-april Message-ID: Dear CBAers, Thanks for all the data in recent weeks. I'm back to teaching now... so the analysis will wait a few weeks (with one exception). That exception is V1674 Her. All northerners can get a 2-hour run, even without violating the "2 airmass" rule-of-thumb. But you can cheat the rule a tad, because the main target now is the behavior of the 8.3 minute periodicity. It's of quite high amplitude now (~0.05 mag), so a 2-hour run will give a quite precise timing. A very high priority. The paper from 2021 has been waiting for the new data - to define the period change adequately. I was very surprised to see so fast a period change last year - but now we need 2022 data to nail it precisely. Of course it would also be nice to tune up the *orbital* ephemeris. That will probably take April data, as well as March. We continue in our emphasis on novae. Good targets now are: V407 Lup (especially), V1369 Cen, NR TrA, and IM Nor. Plus T Pyx, for the rest of March - then we say our annual goodbye to our great friend! EX Hya, BG CMi, and HT Cam are excellent targets among the dwarf novae and novalikes. Then there's DQ Her. Analysis is tough this early in the season (i.e. with short runs). Really a May-June target. But AM CVn is very timely, and will remain so for a few weeks, maybe me (and maybe a lot more). Columbia U went back to normal life this week - hallelujah! I hope you're all well, and ready to rekindle your pre-pandemic life this month! joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Thu Mar 31 23:42:12 2022 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 31 Mar 2022 23:42:12 -0400 Subject: (cba:news) V1674 Her, IM Nor, V407 Lupi Message-ID: Hi CBAers, Now that the Moon has moved into the evening sky, Hercules is much more favorable for observation. I'm hoping to get a good solid month-long 2022 observation of V1674 Her (Nova Her 2021) - to complement the superb coverage of 2021. It should be straightforward, because the star is still decently bright (17), and the 8-minute pulse is strong (0.05 mag). The timing data so far, to my shock, suggests that the spin clock is continuing to speed up violently - even now, long after the eruption. I had predicted that it would slowly asymptote back to the pre-nova spin value. Strangely, no one took my bet. Anyway, the star is now MUCH more favorable for observation, and you can get decently long runs as Hercules slowly climbs higher in the morning sky. So far, the ORBITAL signal has not re-emerged - probably because it was too early in the season to get long runs. But it should be OK now. I'm grateful for your efforts so far, and I hope you'll continue on this wonderful star. I think V407 Lup is a similar star, and I hope southerners can cover that star with a similar campaign. Two other comrades, T Pyx and IM Nor. The 2022 T Pyx campaign can end; the ephemeris is nailed down - and continues to show gradual flattening of the period curve as the star gets fainter. It's now as faint as mag 16 - fainter than it has ever been in history... and the fading is continuous (happening for decades - except for eruptions of course). Re its comrade, IM Nor, no 2022 observations yet... but I'm eager to see if the fast Porb increase continues! In 6 weeks, I will finally transition from "professor" to "research scientist" (cease teaching classes). This will give me much more time to do the analysis of all the wonderful data you guys send me! The V1674 Her paper is just about ready to go, and mainly just waits for a few weeks of 2922 coverage. joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/