Central Bureau for Astronomical Telegrams
IAUC 4245: N Vul 1984 No. 2; NSV 6708
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Circular No. 4245
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
NOVA VULPECULAE 1984 No. 2
G. L. Grasdalen, University of Wyoming, writes: "Broad-band
infrared photometry of Nova Vul 1984 No. 2 obtained by R. D. Gehrz,
University of Minnesota, using the Wyoming Infrared Observatory
(WIRO) indicates the development of an intense emission feature in
the L' (3.6 microns) band beginning 1985 mid-Oct. and steadily increasing
through 1986 May. Circular variable filter (CVF) observations
by G. Grasdalen, M. Greenhouse, T. Hayward and J. Benson (WIRO),
beginning in late May and continuing to the present, reveal lines
at 1.96 (intensity ~ 0.13), 2.04 (0.06), 2.48 (0.19), 2.91 (0.06),
3.03 (0.42), 3.66 (1.00), 3.92 (0.08) and 4.05 (0.08) microns. The
intensities given are relative to the strongest line at 3.66 microns and
have not been corrected for possible telluric absorption and relative
CVF transmission. The line-to-continuum ratio for the 3.66-microns
line exceeds 100 at the 1.3-percent resolution of the CVF. The 2-
and 3-microns spectra are very similar to the spectra of (Nova) V1500
Cyg (1975) reported by Grasdalen and Joyce (1976, Nature 259, 187).
T. Jones, University of Minnesota, obtained infrared photometry of
Nova Vul 1984 No. 2 during 1986 July 30-Aug. 1 using the NASA
Infrared Telescope Facility. The resulting magnitudes were: J =
10.36, H = 10.79, K = 9.23, L' = 6.56, M = 6.01, N = 3.61. In addition,
narrow filters across the 10-microns window gave the following
magnitudes: [7.8 microns] = 2.37, [8.7] = 4.12, [9.8] = 3.93, [10.3] =
3.69, [11.6] = 3.43 and [12.5] = 2.33. CVF observations at WIRO
by Hayward and Benson on Aug. 11 show that the excess in the 7.8-
microns band is due to a strong line at ~ 7.6 microns, probably to be
identified with [Ne VI]. The strength of the line is sufficient to
account for the 7.8-microns flux observed by Jones."
NSV 6708
Further to IAUC 4233 and 4241, R. McNaught, Siding Spring
Observatory, remarks that the identity of NSV 6708 = BV 420 with CoD
-39 9021 is uncertain, since the variable lies 33" north of a
constant star (CoD -39 9021?) of mag 11. His examination of plates
in the Harvard collection covering 1913-1921 and 1933-1952 shows
NSV 6708 variable around B = 10 in mid-1917 and in the range B =
11-13 at times during 1919-1937; generally it was fainter than mag
13 and not recorded. McNaught's Siding Spring patrol plates show
that the current maximum follows a gradual rise at the end of
1985, already to mag 7.5 in 1986 mid-Feb.
1986 August 19 (4245) Brian G. Marsden
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