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IAUC 5910: 1993v; N Cas 1993

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                                                  Circular No. 5910
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

     Robert H. McNaught reports the following measurements of a
comet that he discovered on a U.K. Schmidt Telescope plate taken by
Kenneth S. Russell.  The comet shows a coma of diameter 8" and a
very faint tail 10" long in p.a. 20o.  The object's westward motion
was confirmed in an observation with the Siding Spring 0.61-m
reflector (+ CCD) on Dec. 18.

     1993 UT             R.A. (2000) Decl.        m1
     Dec. 17.46003    3 06 33.47   -56 33 24.0   17.5
          17.50865    3 06 28.62   -56 33 23.1

     Visual magnitude estimates indicate a brightening of this
object: Dec. 15.13 UT, 6.4 (A. Hale, near Orogrande, NM); 16.12, 6.4
(C. Hergenrother, Tucson, AZ); 17.11, 6.3 (C. E. Spratt, Victoria,
BC); 17.23, 5.6 (Hale, El Paso, TX); 17.712, 5.8 (P. Rapavy,
Rimavska Sobota, Slovakia); 18.08, 5.3 (C. E. Spratt, Victoria, BC);
18.11, 5.6 (Hergenrother).
     S. R. Trammell and R. A. Benjamin, University of Texas, report:
"Optical spectropolarimetry (range 450-720 nm; dispersion 0.269
nm/pixel) obtained with the 2.7-m telescope at McDonald Observatory
on Dec. 14.06 UT, shows a high-continuum polarization of 1.84 +/-
0.05 percent at position angle 61o +/- 1o.  There is a 0.4-percent
drop in polarization across H-alpha with a position angle rotation
of 10o +/- 2o, which indicates that some polarization is intrinsic
to the nova and suggests an asymmetric geometry."
     C. E. Woodward, University of Wyoming; and M. A. Greenhouse,
National Air and Space Museum, write:  "Velocity-resolved spectroscopy
of N Cas 1993, obtained on Dec. 15.2 UT using the NASA Infrared
Telescope Facility (+ CSHELL), revealed emission from hydrogen
Br-gamma with FWZI about 1680 km/s.  Substantial structure was
observed in the emission-line profile.  Infrared photometry obtained
by G. F. Lawrence and R. D. Gehrz, University of Minnesota, using
the Mt. Lemmon 1.5-m telescope resulted in the following broadband
magnitudes: Dec. 14.1 UT, J = 4.82 +/- 0.03, H = 4.48 +/- 0.03, K =
4.18 +/- 0.03, L' = 3.65 +/- 0.03, M = 3.00 +/- 0.03 (with InSb
photometer); Dec. 15.1, H = 4.55 +/- 0.03, K = 4.12 +/- 0.03, L =
3.92 +/- 0.03 (with bolometer).  The observed color magnitudes are
consistent with the nova being in a free-free evolutionary state at
this epoch."

1993 December 18               (5910)            Daniel W. E. Green

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