(cba:news) march-april news
jop at astro.columbia.edu
Sat Mar 24 23:14:52 EDT 2007
Apologies for my very long silence. Lots of time needed to take care of
my 95 yo father in Boston; I've been gone for nearly a month. I've
learned a lot about eldercare in the USA - I hope enough to navigate the
harder problems that may lie ahead.
Plenty of change in the CBA world over such a time.
1. The T Pyx coverage, dominated by Bill Allen, has established the
binary phase very accurately; we can now quit for the year.
2. Likewise for DW Cnc, observed by David Boyd, Bruce Dickson, Cindy
Foote, and Tut Campbell. And for Swif0732-13, primarily observed by Bob
Rea. And WX Pyx, with Bob Rea and Berto Monard leading the way. In
these cases, *pulsation* phase rather than orbital.
3. Too late in the season for FS Aur, RR Pic, and RX0704+26.
4. HT Cam and BG CMi are still not adequately done. I strongly
recommend BG CMi - just two nights would enable us to wrap it up for the
5. I dunno about U Gem. Really too late for long runs, and we basically
need 'em to accurately specify the hot spot's amplitude/phase. We'll
have to cover the last part of the cycle next year.
That takes care of basically all the earlier targets. Onward into the
In the SOUTH, a good target over the next week is DT Oct = RX1840-83,
presently in superoutburst. Over the next month, I recommend V382 Vel,
the remnant of a 1999 nova which flashed some beautiful periodic signals
three years back. And RX1039-05 = Sex = (I think) YY Sex, a very likely
AM Her star presently misclassified (probably). The latter looks very
faint, but give it a go - it's very bright in I light, and shows a 2
magnitude modulation in I light. Could be a very feasible and
satisfactory target. And CR Boo (see below).
In the NORTH, I strongly recommend AM CVn, which is now transiting near
local midnight and is definitely feasible for all CBAers. The prime
need this year is timing of the (somewhat) subtle 17 minute orbital
signal. The presence of several more powerful signals at nearby
frequency means that a couple weeks of long, dense runs are needed.
Now's the time. The other long-term target is CR Boo, which is another
bright AM CVn star chock full of periods, which has not received very
close attention since the CBA went global. At 1346+08, it's very well
placed for all observers, and I hope we can assemble some all-day light
curves for it.
Finally, there are eclipsers, which need occasional potshots to update
the binary ephemeris. AC Cnc, BP Lyn, and UMa6 = H0928+50 all could use
some attention - one or two eclipses is enough.
So that's it: DT Oct, YY Sex, CR Boo in the south. AM CVn, CR Boo, BG
CMi, and the eclipsers in the north.
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