(cba:news) April-May stars
jop at astro.columbia.edu
Sun Apr 26 08:55:58 EDT 2020
Some shiny new targets for the southern fall. Happens every year.
"Nova Sco 1437". We have excellent data from 2018, but strangely missed
coverage last year. It's a deep eclipser, an IP, and possibly the
remnant of an ancient nova. Seems not to have a variable-star name yet.
In southern Scorpius, it's for the australites only... but is worth
pounding very hard on these long southern nights.
V407 Lupi (Nova Lupi 2016). Another superb choice, with orbital and IP
modulations. Recently discovered (obviously).
IM Nor. Yet another old (recurrent) nova. Usually near 18th mag, so
this might be a Gordon-only target.
V617 Sgr and WX Cen. Two supersoft (according to me; there are
dissenters) binaries with large dP/dt terms in their eclipse
ephemerides. Easy targets; at -35 degrees, V617 might be available to
V1223 Sgr. At V=13 minutes and delta = -31, this one is available to
most northerners. We - along with everyone else - have neglected this
famous IP, and it's time to establish a solid ephemeris.
- - - -
THE AM CVN STAR CAMPAIGNS.
I recommend continuing on AM CVn for another ~3 weeks, to give those
superhumps a chance to change their periods (slightly but importantly!).
No need for very long runs, though.
I recommend backing off on V803 Cen... and somewhat on CR Boo (latter is
debatable). These stars are in their oscillating states ("dwarf-nova"),
and those are very, very difficult to analyze. Should either star get
very faint (V>17), then they become high priority targets.
HP Lib. Definitely. Very good target! Long runs highly recommended,
although all runs will be helpful.
SDSS J141118.31+481257.6. Back in the sky, perfectly placed.
- - - -
MAXIE (J1820+070). Keep watching. Short time series, unless it erupts.
V1494 Aquilae. We have to keep tracking this very bright and eclipsing
DQ Her . Time to resume our watch. Timing of the eclipse is of
interest, but try to get a timing on the 71 sec oscillation. This is
not difficult to do in a lengthy time series, but requires a cycle time
(time between mid-integrations) of 25 seconds or less.
OV Boo. This is a definite reach, at V~18 and eclipsing. But just a few
eclipses this year will get the binary ephemeris nailed down, and the
paper finished at last.
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