From jop at astro.columbia.edu  Wed Nov  3 11:44:46 2021
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 3 Nov 2021 11:44:46 -0400
Subject: (cba:news) V1674 Her uodate, and AAVSO
Message-ID: <8a20d3a6-cfb4-7c7c-5d83-7744ff2097dd@astro.columbia.edu>

Hi CBAers,

Okay, I admit I'm a little obsessed with this star... but I urge you to 
keep going on V1674 Her as long as possible - fearlessly venturing into 
the woolly wilds of high-airmass.  Because the nova is pretty highly 
reddened, its effective color is similar to that of field stars - 
implying that you can observe at high airmass (3, perhaps) with not much 
degradation (other than the general degradation of high airmass).

The reason I stress it is that there is now borderline evidence that the 
white-dwarf spin period is decreasing - just over the 3 months of 
coverage.  This is ~50x faster than anything we've ever seen - and we've 
been observing WD spin periods for 40 years.  In addition, the average 
peak-to-trough amplitude of this 8-minute guy is now up to 0.07  mag - 
so it's pretty easy to detect.  Those of you have been observing it can 
see it in just your own data, even in just one decent night.  The 
shortness of the runs (southern Hercules in November!) is a problem - 
but it's a problem we can overcome with a large longitude spread in the 
observations.

I'm sorry to say that I won't be at this weekend's AAVSO.  My wife's 
recovery from hip surgery has been slower than expected, and I just 
can't leave for a few more weeks.  I expect to be watching from home, 
though.

We've never had a CBA zoom call... and if someone can set it up, I think 
it would be a good thing. Jonathan is the natural choice, but I think he 
has a lot of new job responsibilities now - so maybe there's another 
volunteer??

Re stars, Enrique is taking good care of the IPs.  I'm concentrating 
mostly on the orbital light curves of old novae, especially the 
eclipsers.  ALL eclipsing old novae are excellent targets - and I'll 
send a more detailed and curated list within a few days.

joe
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