(cba:news) strike V1974 Cyg

Joe Patterson jop at astro.columbia.edu
Tue Sep 12 03:12:06 EDT 2017

Hi CBAers,

Delete V1974 Cygni from the menu.  I finished the analysis of all the 
data (dominated by David Cejudo's), and there is a very clear detection 
of the orbital signal.  In fact, two, separated by ~90 days (we never 
had that before, and it's very useful to connect the years).

The detection and measurement of the phase of the orbital signal was the 
goal... and we have it now.  Especially nice since the detection is 
uncontaminated by superhumps; we never had that before, also.  Two other 
things we'd *like* to know are:

(1) What is the phase of the radial velocity variation when the light 
reaches its orbital max?

(2) Just how bright is the continuum?  The 4000-8000 A region, where we 
observe the star at "17.12", is probably dominated by the O III emission 
at 5007 A.  That emission from the shell needs to be subtracted to learn 
how bright the central object is.

Only a very motivated spectroscopist could answer (1); so far, none have 
piped up.  (2) is best learned from a single high-quality spectrum; 
someone might have that.  But if you have a filter which excludes that 
terrible monstrosity at 4959/5007 A, and preferably also H-alpha, you 
might learn that.  Might be worth an effort.  You don't necessarily need 
to detect the periodicity (at 0.08126 days); just measuring the 
brightness of a clean, line-free continuum would allow us to correct our 
measurement for all that unwanted and so-far-unmeasured nebular light.

Pretty nice result for "the nova of the century"!

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