Central Bureau for Astronomical Telegrams
IAUC 5244: N LMC 1991; AM Her
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Circular No. 5244
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
NOVA IN THE LARGE MAGELLANIC CLOUD 1991
W. Liller, Vina del Mar, Chile, reports his discovery with
Problicom of a nova in the LMC. R. H. McNaught, Anglo-Australian
Observatory, provides the following precise position obtained from
an Apr. 16 U.K. Schmidt plate taken by S. M. Hughes and M. Hartley:
R.A. = 5h04m12s.70, Decl. = -70 22'16".2 (equinox 1950.0). A nearby
star of mag about 14 is located at R.A. = 5h03m56s.90, Decl. =
-70 22'03".3. Available magnitude estimates (photovisual or visual
unless otherwise noted): Apr. 11.43, 20 (McNaught); 12.41, 19.5
(McNaught); 13.41, 19 (McNaught); 14.5, [13 (P. Camilleri, Cobram,
Victoria); 15.120, [14 (Liller; red filter); 15.5, [13 (Camilleri);
16.40, 15 (McNaught); 16.42, [14.5 (G. Garradd, Tamworth, N.S.W.);
16.50, [13 (Camilleri); 18.036 and 18.041, 12.3 (Liller, minus UV
filter); 18.53, 12.4 (Camilleri); 19.40, 12.6 (Camilleri).
McNaught's preliminary magnitudes are from U.K. Schmidt plates, and
he notes that nothing appears in this position on the UKST J, R, and
I and the ESO B and R surveys.
AM HERCULIS
K. Beuermann and P. Predehl, Max-Planck-Institut fur Extraterrestrische
Physik; H.-C. Thomas, Max-Planck-Institut fur Astrophysik;
D. de Martino, International Ultraviolet Explorer, VILSPA; H. Barwig
and K.-H. Mantel, Universitatssternwarte Munchen, report: "AM Her
has left its extended low state and returned to a high state.
Photoelectric magnitudes obtained with the Wendelstein 0.8-m telescope
were Mar. 14.12 UT, V = 15.2; Apr. 5.0, 15.0:; 7.06, 13.2; 13.01,
13.6 (about 0.2 mag). A 12000-s on-axis observation with the ROSAT
PSPC from Apr. 12.35 to 13.63 gave a soft x-ray light curve with
orbital minimum between magnetic phases about 0.0 and 0.2, a mean
count rate of about 150 cts/s, and large-amplitude flaring up to 400
cts/s in 79-s bins. Our simultaneous five-color photometry on Mt.
Wendelstein showed that the orbital light curve resumed its normal
shape with a double-humped maximum and a minimum at magnetic phase
0.6. Orbital variation was V = 12.7 to 13.6 (about 0.2). The optical
flux was also modulated by large-amplitude flickering. IUE
coverage on Apr. 12 and 13 showed the presence of the usual strong
emission lines of N V, Si IV, C IV, and He II. The continuum flux
displayed a quasi-sinusoidal modulation with minimum and maximum at
phases 0.1 and 0.6 and 30-percent amplitude. These results indicate
that AM Herculis returned to a normal high state dominated by
accretion onto its main pole."
1991 April 19 (5244) Daniel W. E. Green
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