(cba:news) March stars

Joe Patterson jop at astro.columbia.edu
Mon Mar 11 11:06:40 EST 2002

Dear CBAers,

Some news notes on campaigns...

The campaign on BP Lyn was intense, led by Tonny, Jerry Foote, and Dave
Skillman.  Just one week of data, but it was very dense, and led to a
severe upper limit on the presence of superhumps (<0.017 mag).  Very
nice - and weird - orbital light curve.  We'll print it in the atlas
that Jonathan is preparing.  So... out with BP Lyn, we've got all we want
from it.

So far, the vigil on EC0511-7955 has been just Bob Rea and Berto Monard.
The star has been fascinating... any reinforcements out there?  We're
going to keep gunning for this star.

The prime target this month is a quite faint star, at V=17.6.  Its full
name is 1RXS J105010.3-140431, but let's call it RX1050-14.  Normally I
don't like to recommend stars this faint to the CBA, but this one is just
too interesting to pass up.  It appears to be a close relative of WZ Sge;
a recent paper (A&A 376, 448) suggested a secondary-star mass of ~0.02 Mo
or so.  Virtually nothing is known about variability (hence its lack
of a variable-star name), so anything we find is big plus.  An actual
outburst, or even - gasp - a superoutburst, now that would be precious!
This is also a BOTH-HEMISPHERES TARGET... a good chance for us to get true
round-the-world coverage (atoning for our lack of representation in East
Asia and South America).

A finding chart is in the just-cited paper by Mennickent et al.  It looks
like there is a suitable comparison star about 1.4 arcmin E of the

We've gotten only a little coverage on GK Per, mainly from Brian Martin
(who claims the first CBA frozen-butt award, richly deserved, for
observing in -30 C weather).  To my amazement, Brian's data showed strong
6-minute oscillations.  So this becomes a great first object of the night
for you borealites!

Finally it's time to wake up AM CVn again.  One of our top-gun CVs.  In
addition to the 1051/525 s period which we have already studied enough,
there is a 1028 s signal, slightly weaker and signifying the orbital
period.  We have not timed this signal in about 4 years, and we need to
acquire a 2002 seasonal timing to check for changes in orbital period.
Good target for northern scopes.  We like that comp star just 2 arcmin
south of AM CVn.

So: in the north, GK Per, RX1050-14, AM CVn
    in the south, EC0511-7955, RX1050-14

Happy observing!


More information about the cba-public mailing list