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IAUC 5683: 1992bq; N Cyg 1992; N LMC 1992

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                                                  Circular No. 5683
Central Bureau for Astronomical Telegrams
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

     M. Hamuy, Cerro Tololo Interamerican Observatory; and J. Maza,
University of Chile, report the discovery of an apparent supernova
(mpg about 17) by R. Antezana (University of Chile) on a
20-min unfiltered IIa-O plate taken by G. Valladares with the CTIO
Curtis Schmidt telescope on Dec. 20.32 UT.  SN 1992bq is located
15" east and 1" south of the nucleus of a spiral galaxy at
R.A. = 10h14m43s.6, Decl. = -34 30'08" (equinox 1950.0).  Confirming
observations were made by R. Aviles from CCD B, V, R, and I images
obtained on Dec. 23.31 with the CTIO 0.9-m telescope.

     C. E. Woodward, University of Wyoming; and M. A. Greenhouse,
National Air and Space Museum, Smithsonian Institution, write:
"Analysis of infrared spectra of N Cyg 1992 obtained on Sept.
8.3 UT using the 2.1-m telescope (+ CRSP) at Kitt Peak National
Observatory (IAUC 5612) have revealed an emission line observed
at 1.250 +/- 0.002 microns.  We tentatively identify this feature
as the 2s**2 2p**4 3P_2-3P_1 transition of [S IX].  Strong
hydrogen Pa beta emission also was present.  Astronomical
observation of the [S IX] transition has not been reported
previously.  This line may be accompanied by the 3P_1-3P_0
transition of [S IX] at 3.75 microns, since its excitation
temperature is only 4000 K higher than that of the 3P_2-3P_1
transition.  However, the critical density for collisional
de-excitation of the 3.75-micron line is approximately a factor
of 4 lower than that of the 1.25-micron line.  Detailed balance
calculations show that one expects a [S IX] 1.25-micron/3.75-micron
intensity ratio of roughly 15 at log T_e (K) = 6 and log
$n_e (cm**-3 < 8.  We find the following line flux
estimates (x 10**-18 W c,**-2: [S IX], 0.97 +/- 0.08; Pa beta, 11.45
+/- 0.46."

     Additional photometry (cf. IAUC 5669) by A. C. Gilmore
obtained with the 0.6-m f/16 Cassegrain at Mt. John
University Observatory (reference star CPD -65 433):
Dec. 14.46 UT, V = 14.72 +/- 0.02, U-B = -0.86 +/- 0.11, B-V =
-0.45 +/- 0.05, V-R = +1.73 +/- 0.04.

1992 December 28               (5683)            Daniel W. E. Green

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