Central Bureau for Astronomical Telegrams
IAUC 6090: 1994o; 1994aa
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Circular No. 6090
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 TWX 710-320-6842 ASTROGRAM CAM
MARSDEN@CFA.HARVARD.EDU or GREEN@CFA.HARVARD.EDU (science)
PERIODIC COMET MACHHOLZ 2 (1994o)
P. Pravec, Ondrejov Observatory, reports that his CCD observations
with the 0.65-m f/3.6 reflector on Oct. 5.14 UT showed component D to
consist of two condensations of similar brightness and separated by 7"
in p.a. 112-292 deg. Component C was marginally visible at separation
10" in p.a. 185 deg but almost hidden by the coma of component D.
Component E was also visible at separation about 80" in p.a. 9 deg
from component D. There was also a trail of material along a line in
p.a. 10-190 deg near component D; this spanned from 2'.0 at the
southern end to 5' at the northern and was measured on a composite
image of 240-s total integration (although it was also visible on
individual 60-s images). The duplicity of component D is also
suggested on Sept. 2.1 and 4.1, when the single condensation was
elongated to about the same extent and in the same direction as the
resolved condensations are now. The elongation is less prominent, but
still present, in images from Aug. 30.1. On Sept. 23.1 component D was
significantly more active and better condensed than on other occasions.
Total visual magnitude estimates: component A, Oct. 2.49 UT, 9.1
(A. Hale, near Chaparral, NM, 0.20-m reflector); 3.49, 9.2 (C. S.
Morris, southern California, 0.26-m reflector); 4.15, 9.2 (J. D.
Shanklin, Cambridge, England, 0.33-m reflector); 5.45, 9.8 (G. Kronk,
Troy, IL, 0.33-m reflector); component B, Sept. 24.52 UT, 12.2
(Morris); Oct. 3.50, 12.5: (Morris); component D, Oct. 2.49, 9.5
(Hale); 3.49, 9.8 (Morris); 4.15, 10.4 (Shanklin); 5.44, 11.4 (Kronk);
component E, Sept. 11.50 UT, 12.2 (Morris); 24.51, 12.8 (Morris); Oct.
3.50, 12.8 (Morris).
SUPERNOVA 1994aa IN NGC 1320
A. Riess and R. Kirshner, Harvard-Smithsonian Center for
Astrophysics, communicate: "A spectrogram obtained with the Multiple
Mirror Telescope (+ Blue Channel spectrograph, range 400-800 nm) on Oct. 5
shows that SN1994aa is a type Ia supernova about 1 month past maximum.
M. Dennefeld reports that a low-dispersion spectrum (range 370-715
nm, resolution 1 nm) was obtained with the 1.93-m telescope at the
Haute Provence Observatory on Oct. 6.08 UT. The absence of hydrogen
lines and the presence of a weak Si II 615-nm absorption line, together
with various broad emissions, suggest a type Ia supernova about 2
months past maximum.
Corrigendum. On IAUC 6088, the discovery date should have been
given as Sept. 14 and the declination offset as 1".8 south.
1994 October 6 (6090) Brian G. Marsden
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