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(cba:news) ASASSN-18ey... and AM CVn (Joe Patterson) [2019-03-12T13:02:49Z]


Hi CBAers,

Joe U's discovery of the rebrightening of our old friend from last year is posted on ATel 12567 (they post these things in <15 minutes, so be careful when you send!). Let's brave those cold March mornings to find what's going on with Maxi. With that long period of 17 hours. we can't cover an orbit (except by splicing data from several longitudes). But with a V filter, you can start well above our usual limit of 2.0 airmasses (even to 3.0), because the extinction is fairly low and well-defined.

And let's go after AM CVn with similar intensity. March is a great season for this star, and although the raw light curve doesn't look like much, it is flashing at least two superhumps (positive at 525.6 s - the first overtone - plus the 1028 s orbital signal. With enough time baseline, we get to see those periods *change* - minutely but with great consequences for the star's structure and evolution. LONG time series are needed, but stick with a clear or minus-blue filter (so adhere to the <2.0 airmass convention).

joe p

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