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IAUC 5544: N Cyg 1992; 1992d

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                                                  Circular No. 5544
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


NOVA CYGNI 1992
     Y. J. Pendleton, Ames Research Center, NASA, communicates: "R.
Gehrz, C. Kaminski, N. Jennerjohn, S. Sandford, L. Allamandola, and
I report near-infrared spectroscopy of Nova Cyg 1992 in a 2".7 beam
using the Cooled Grating Array Spectrometer of the NASA Infrared
Telescope Facility.  The spectrum (range 2.9-3.77 microns,
resolution 0.018 micron) taken over a 30-min interval on May 29.6 UT
showed several prominent emission features.  Subsequent high-
resolution observations of those features (taken on May 30.6 and May
31.5 over 60- and 90-min intervals, respectively; resolution 0.004
micron) were made with half-channel grating shifts to obtain a
complete spectrum.  Preliminary analysis shows a fairly smooth
continuum due to free-free emission on which are superposed several H
emission lines (Pf-epsilon, Pf-delta, and Pf-gamma) and some
unidentified emission lines (near 3.08 microns).  The lines are
resolved and preliminary analyses indicate the following intrinsic
line FWHM values:  Pf-gamma (3.739 microns), 2400 km/s; Pf-delta
(3.29 microns), 3000 km/s.  The former is quite symmetric while the
latter is asymmetric.  Pf-gamma is the strongest line and relative
strengths are Pf-gamma/Pf-delta about 1.35 and Pf-gamma/Pf-epsilon
about 2.  There appear to be two lines blended in the 3.08-micron
region and the strength of these features is comparable to the Pf-
delta line.  There is no evidence for infrared coronal emission at
this time.  There is, however, evidence of line splitting in the
Pf-epsilon line (3.038 microns) at locations up to 7 wavenumbers on
either side of the line center.  Line splitting may arise from a
multiple, toroidal, or clumpy shell structure in the ejecta."
     R. Gehrz, T. J. Jones, and G. Lawrence, University of
Minnesota, report the following infrared magnitudes obtained with a
bolometer system at O'Brien Observatory:  May 19.4 UT, J = 7.0, H =
7.2, K = 6.6, L = 5.7, M > 4.9 (3-sigma detection), N > 1.2; May
29.4, L > 4.1.
     Further visual magnitude estimates forwarded by the AAVSO:
June 9.92 UT, 8.4 (P. Schmeer, Bischmisheim, Germany); 10.35, 8.5
(P. Collins, Boulder, CO); 10.98, 8.4 (B. H. Granslo, Fjellhamar,
Norway); 11.35, 8.7 (Collins).


COMET TANAKA-MACHHOLZ (1992d)
     Total visual magnitude estimates (cf. IAUC 5531):  June 3.21
UT, 8.5 (R. Donner, Santa Barbara, CA, 0.25-m reflector); 5.99, 9.1
(H. Luthen, Hamburg, Germany, 0.20-m reflector); 11.31, 8.8 (J. E.
Bortle, Stormville, NY, 0.32-m reflector).


1992 June 15                   (5544)            Daniel W. E. Green

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