Central Bureau for Astronomical Telegrams
IAUC 5254: N Oph 1991; N Her 1991; AM Her
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Read IAUC 5255
Circular No. 5254
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 OPHIUCHI 1991
C. E. Woodward, R. D. Gehrz, and G. Lawrence, University of
Minnesota; and R. Pina, University of California at San Diego, report the
following infrared broadband magnitudes measured in a 15" beam of
Nova Oph 1991, obtained using a bolometer on the 1.52-m Mt. Lemmon
telescope and the University of Minnesota remote observing link on
Apr. 24.38 UT: H = 7.68 +/- 0.09, K = 7.35 +/- 0.12, L = 6.52 +/-
0.11, M = 5.45 +/- 0.30.
Visual magnitude estimates: Apr. 15.56 UT, 11.3 (P. Nelson,
Ellinbank, Vic.); 17.56, 11.1 (P. F. Williams, Heathcote, N.S.W.);
20.50, 11.5 (D. A. J. Seargent, The Entrance, N.S.W.); 22.12, 11.1
(A. Pereira, Linda-a-Velha, Portugal); 23.77, 11.0 (A. Pearce,
Scarborough, W.A.); 25.74, 11.1 (A. F. A. L. Jones, Nelson, N.Z.);
26.68, 11.1 (Jones).
NOVA HERCULIS 1991
N. M. Ashok, T. Chandrasekhar, and S. R. Prabhakaran, Physical
Research Laboratory, Ahmedabad, report: ''Observations of Nova Her
1991 in the near-infrared (1-3 microns) were made at the 1.2-m
Gurushikhar telescope with a InSb photometer during Apr. 5-22. J,
H, and K magnitudes show a steady decline in the brightness of the
nova: Apr. 5.97 UT, J = 7.37, H = 5.59, K = 4.29; 6.96, 7.44, 5.69,
4.26; 9.95, 7.71, 6.13, 4.51; 10.89, 7.81, 5.98 4.47; 12.91, 7.98,
5.97 4.42; 15.91, 8.0, 6.16, 4.60; 16.94, 8.5, 6.26, 4.67; 17.96,
8.4, 6.30, 4.71; 21.92, 9.9, 6.80, 5.05; 22.96, 9.6, 7.02, 5.20. In
comparison with other observations (IAUC 5230), it appears that the
2.2-micron brightness of the nova showed a peak between Apr. 1 and
5, associated with dust formation with K </= 4.2. Our observations
with a CVF spectrophotometer in the 1.7- to 2.5-micron region show a
strong emission feature at 1.99 +/- 0.03 microns with day-to-day
variability."
Visual magnitude estimates (cf. IAUC 5238): Apr. 15.10 UT,
12.4 (P. Schmeer, Bischmisheim, Germany); 16.87, 12.3 (A. Pearce,
Dowerin, W.A.); 18.03, 12.4 (B. H. Granslo, Fjellhamar, Norway);
19.2, 13.0 (E. Halbach, Estes Park, CO); 21.06, 13.3 (M. Verdenet,
Bourbon-Lancy, France); 23.33, 13.2 (J. McKenna, Upper Montclair,
NJ); 24.5, 13.3 (Halbach).
AM HERCULIS
Visual magnitude estimates by S. Korth, Dusseldorf, Germany:
Apr. 3.16 UT, 14.3; 11.15, 13.3; 13.05, 13.2; 19.99, 13.0; 20.93,
12.7.
1991 April 29 (5254) Daniel W. E. Green
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