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IAUC 5674: N Cyg 1992; P/SCHWASSMANN-WACHMANN 1

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                                                  Circular No. 5674
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
     M. A. Greenhouse, National Air and Space Museum (NASM); C. E.
Woodward, University of Wyoming; J. Fischer, Naval Research Laboratory;
and H. A. Smith, NASM, communicate:  "Spectroscopy of N Cyg
1992 obtained on Oct. 18.35 UT (243 days after outburst) with the
NASA Infrared Telescope Facility (+ CGAS) reveals the following
infrared coronal lines (wavelengths listed are the observed values,
with uncertainty in last digit given in parentheses):  [Al VI]
3.657(2)-microns, 2s2 2p4 3P1-3P0; [Al VIII] 3.699(2)-microns, 2s2
2p2 3P1-3P2; [Mg VIII] 3.030(2)-microns, 2s2 2p2 2P1/2-3P3/2; and a
feature at 3.09(1) microns tentatively identified as [Ca IX] 3s3p
3P1-3P2.  Their integrated intensities were (in units of 10E-10 erg
sE-1 cmE-2):  [Al VI], 0.12 +/- 0.01; [Al VIII], 0.020 +/- 0.008;
[Mg VIII], 5.20 +/- 0.04; [Ca IX], 0.08 +/- 0.02.  The observed
free-free flux density was 0.50 +/- 0.09 Jy at 3.6 microns.  The
lines were velocity-resolved at about 2600 km/s FWHM.  The Al and
Mg lines have been observed previously in two other novae (Greenhouse
et al. 1990, Ap.J. 352, 307), and suggest that N Cyg 1992 occurred
on an ONeMg white dwarf (Starrfield et al. 1986, Ap.J. 303,
L5).  The Ca transition has not been reported previously in an
astronomical source.  We note that the infrared Ca transition
discussed here should be accompanied by a 3s2 1S0-3s3p 3P2 magnetic
quadrapole transition at 67.61 nm.  The [Al VI] line was first
observed in N Cyg 1992 on Sept. 9.29 (IAUC 5612) at an intensity of
1.10 x 10E-12 erg sE-1 cmE-2.  The increased [Al VI] intensity and
the large [Mg VIII]/[Al VI] intensity ratio reported here suggests
that the coronal line phase is near maximum.  The observed line
width suggests that no appreciable deceleration of the ejecta has
occurred since the onset of the optically thin emission-line phase
(e.g., Pendelton et al., IAUC 5544).  Additional infrared spectroscopy
covering M, N, and Q bands are needed and should reveal
similar emissions."


PERIODIC COMET SCHWASSMANN-WACHMANN 1
     This comet is again in outburst, as reported by I. Ferrin,
National Observatory of Venezuela, and A. Nakamura, Kuma, Japan, who
provide the following total visual magnitude estimates:  Nov. 24.69
UT, [14.5 (Nakamura, 0.60-m reflector); 30.70, 13.3 (Nakamura);
Dec. 2.72, 13.1 (Nakamura); 5.03, 14.1 (Ferrin, 1-m Schmidt
telescope + CCD).


1992 December 10               (5674)            Daniel W. E. Green

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