(cba:news) more stars of march
jop at astro.columbia.edu
Mon Mar 9 07:25:23 EST 1998
Dear CBAers, March 9, 1998.
Got a few amendments to yesterday's message, mainly for australites.
I spent a few hours studying the AH Men data for the whole season. I
think the data are complete enough now to end for the year. All
three signals (orbit, positive and negative superhumps) are pretty
well delineated. So let's leave it till October.
I didn't mention it before because I thought the star was too faint
(though it's on the Most Wanted list), but after a few days of watching
the wave in CP Pup's light curve, I now think the humps in this star
can be observed by small telescopes. Very healthy humps most nights
(not all) at P=90 min in this V=15.4 star. Go for it.
I also think DI Cru, the star flagged by Diaz and Steiner (and Kato and
Morel) and described below, is well worth a long campaign by
smallscopers in the south. It's bright enough to survive much moon and
cloud, and as a possible relative of V Sge is of great interest to us.
Perfect time of year too, I reckon.
But I hope you give MM Hya top priority. We've been waiting a long
time for this sonofagun!
Here's the DI Cru info...
> According to the recent article by Steiner and Diaz (PASP in press),
>HD104994, now named DI Cru, shows peculiar characteristic common to the
>peculiar "novalike" V Sge. The spectrum of DI Cru is WR, resembling that
>of V Sge, the orbital period 7.46 hr (Niemela et al.). Being 10-th mag
>object, this star should deserve a handy target for small telescopes.
>(The only regret for me is that the star locates too south..). It would
>be interesting to see whether the star shows long-term behavior similar to
>that of V Sge.
I notice that a fine chart and deep photoelectric sequence exists
for the region of DI Cru. It is in Astron. Astrophys. Suppl.(1973)12,365-380
by G. Lynga and S. Wramdemark. In area CB, HD 104994 is identified and measured
as Star 11, V=10.93, B-V =-0.06, U-B =-0.84. The nearest star of somewhat
similar brightness is Star 14 (V = 10.36, B-V = 1.22, U-B = 1.05) at
(1950) 12:03:10 -61:50.9.
Star 21 has V = 10.97, B-V = 1.00, U-B = 0.75. It is at (1950) 12:05:06,
HD 104994 is also on HDE chart 149, very close to the left edge and just
south following HD 104901, a double star (d = 26").
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