Central Bureau for Astronomical Telegrams
IAUC 5273: N Her 1991; N Oph 1991; 1991T
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Read IAUC 5274
Circular No. 5273
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 HERCULIS 1991
M. J. Barlow, University College, London; C. J. Skinner,
Jodrell Bank; and K. Justtanont, NASA Ames Research Center, communicate:
"Mid-infrared spectra (resolving power 80) of Nova Her 1991
taken at the U.K. Infrared Telescope (UKIRT) on May 21.5 UT show a
continuum falling from 2.6 Jy at 8.5 microns to 2.0 Jy at 20.0
microns. There was a broad feature rising sharply from the continuum
at 8.5 microns to a plateau between 9.6 and 11.2 microns, falling
smoothly to 13 microns. The flux at 10.0 microns was 8.0 Jy. No
line emission was observed in the 7.6- to 13.3-micron and 16- to
24-micron regions."
K. Krisciunas, Joint Astronomy Centre, Hilo, reports that the
real-time near-infrared photometry of Nova Her 1991 obtained with
the UKIRT on Mar. 26.67 UT (cf. IAUC 5224) should be corrected as
follows: J = 5.99, H = 5.62, K = 5.26 (uncertainties +/- 0.05 mag).
The comparison star used for this calibration was HD 129653.
Visual magnitude estimates (cf. IAUC 5265): May 8.34, 14.0 (R.
J. Modic, Richmond Heights, OH); 10.28, 14.1 (Modic); 11.37, 14.1
(Modic); 17.98, 13.8 (R. Monella, Covo, Italy); 19.96, 14.0 (Monella).
NOVA OPHIUCHI 1991
Barlow, Skinner, and Justtanont also report the following:
"Mid-infrared spectra (resolving power 80) of Nova Oph 1991, taken
at the UKIRT on May 22.5 UT, show no line or continuum emission.
Upper limits to possible continuum emission were 0.4 Jy at 10.0
microns and 0.4 Jy at 20.0 microns."
Photometry by A. C. Gilmore with the 0.6-m Cassegrain reflector
at Mount John University Observatory on Apr. 30.68 UT: V = 12.13
+/- 0.01, U-B = -0.22 +/- 0.01, B-V = +0.86 +/- 0.01, V-R = +1.06
+/- 0.03, V-I = +1.3 +/- 0.2.
Visual magnitude estimates (cf. IAUC 5254): Apr. 30.64 UT,
12.0 (A. Pearce, Scarborough, W.A.); May 1.60, 12.1 (Pearce); 12.84,
12.3 (Pearce); 14.10, 11.7 (A. Pereira, Cabo da Roca, Portugal);
16.85, 13.2 (Pearce).
SUPERNOVA 1991T IN NGC 4527
Revised photometry from J. Holberg et al. (cf. IAUC 5270): May
6.270 UT, V = 11.612 +/- 0.055, B-V = +0.374 +/- 0.016, U-B = -0.208
+/- 0.019.
1991 May 23 (5273) Daniel W. E. Green
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