(cba:news) changing of the guard

Joe Patterson jop at astro.columbia.edu
Wed Feb 27 10:25:13 EST 2002

Dear CBAers,

Some pretty substantial news about campaign stars...

Bob Rea and Berto Monard have been plugging away on EC0511-7955, a 15th
mag novalike variable described in a recent MNRAS paper by Chen et al.
(describing photometry and spectroscopy of CVs from South Africa).  Both
have struggled with weather, but yesterday I spent half the day studying
the spliced light curves over a 20-day baseline.  And lo!  Some beautiful
periods emerged!  The orbital period is manifest by a shallow eclipse, of
variable depth but recurring with a strict 0.1414 d period.  Negative
superhumps at 0.1368 and 0.0696 d also occur; these are the wo+N and 2wo+N
components, in the terminology that is becoming familiar.  Finally the
"nodal" signal at 4.2 d also appears to be present.

So this star scores a 5.9 for technical merit... but only a 5.3 for
presentation, since weather ravages have kept the coverage spotty.  Let's
make a big push now on Mr. 511, and impress those judges in the finals!

In the north, the BK Lyn campaign has come to an end.  The star has a
very large negative (nodal) superhump, plus the nodal frequency itself
(0.393 c/day).  We have a 70-day baseline, so that's definitely good
enough.  Very late in the observing season (May), we'll want a few more
timings - so we can explore the prospect of counting cycles *between*
observing seasons (not yet achieved for any superhumps).  What a beauty.
But for now, let's get it off the stage and make room for....

BP Lyn = PG0859+415.  Another "SW Sex star" with periodic humps (so far,
the only known hump is orbital... but that's where we come in).  Nicely
positioned in the evening sky for attack by the CBA phalanx.

Plus TT Boo, still humping away in superoutburst.  Despite its brightness,
we've just never managed to get good coverage of this star... badly timed
superoutbursts I guess.  Let's see if we can get this one covered!

Oh, and let's show DW UMa off the stage too.  We've got a good season's
coverage, with a very fine apsidal superhump.  Mission accomplished...
make way for youth!

So an easy program: EC0511, BP Lyn, TT Boo.


by the way Jonathan is about to deploy some interesting new pages on the
website... right, Jonathan?

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