Central Bureau for Astronomical Telegrams
IAUC 4975: N LMC 1990 No. 2; BZ UMa; 1989c1
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Circular No. 4975
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 1990 No. 2
K. Sekiguchi, South African Astronomical Observatory, reports
his preliminary reduction of spectra obtained by R. S. Stobie on
Feb. 21 and 25 (range 340-540 nm) and Feb. 22 (range 340-720 nm) at
SAAO Sutherland. The spectrum on Feb. 22 shows a blue continuum,
and the Balmer lines have narrow emission components (FWHM approximately
1200 km/s) with extensive wings (FWZI approximately 10 000
km/s). He II 468.6-nm and 541.2-nm emission lines are narrow and
the He II 468.6-nm line is the strongest line in the spectrum. At
no time did the spectrum show any of the forbidden line emission.
This, along with the earlier spectroscopy (IAUC 4964), strongly
suggests that the nova is a recurrent nova of U Sco and V394 CrA type.
BZ URSAE MAJORIS
R. Claudi, A. Bianchini, and U. Munari, Padova and Asiago
Observatories, communicate: "Spectroscopic observations of the
dwarf nova BZ UMa, obtained on Mar. 4 and 5 with the Boller and
Chivens spectrograph (+ CCD) on the Asiago 1.8-m telescope, have
revealed a pronounced periodic modulation of a complex H-alpha
emission profile. The derived orbital period is about 1.62 hr.
The FWHM of the H-alpha emission profile is about 1420 km/s,
while the velocity separation in the doubled-peaked profile is
about 660 km/s. The derived orbital period places BZ UMa below
the CVs period gap, suggesting a possible classification of this
dwarf nova among the SU UMa stars."
COMET AUSTIN (1989c1)
A. C. Gilmore reports that a 20-min blue exposure with the
Mount John Observatory 0.6-m Cassegrain telescope on Mar. 2.37 UT
(in moonlight) shows a coma 2'.5 in diameter with a dust tail
1'.3 wide extending 5' in p.a. 155 deg. The ion tail had three
main components at p.a. 95 deg, 102 deg (brightest), and 113 deg
(faintest), all longer than 20' (to the film's edge).
Total visual magnitude estimates (cf. IAUC 4970): Feb. 27.39
UT, 7.7 (P. M. Kilmartin, Mount John Observatory, 10x50 binoculars);
28.13, 6.8 (C. S. Morris, Whitaker Peak, CA, 20x80 binoculars); Mar.
1.36, 6.8 (A. Jones, Nelson, N.Z., 0.04-m refractor); 4.38, 7.2
(Kilmartin); 5.50, 6.5 (A. Pearce, Scarborough, W.A., 20x80 binoculars).
1990 March 7 (4975) Daniel W. E. Green
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