Central Bureau for Astronomical Telegrams
IAUC 3613: GX 339-4 = 4U 1658-48; SN IN NGC 6946; 1980b
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Read IAUC 3614
Circular No. 3613
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 617-864-5758
GX 339-4 = 4U 1658-48
J. Grindlay, Harvard College Observatory, reports that the optical
counterpart of 4U 1658-48 had returned to a high state at
least as of May 7 (cf. IAUC 3585, 3586, 3609). The transition probably
occurred between Apr. 10 (IAUC 3594) and May 7. Spectra were
obtained on May 7.25 UT with the 4-m telescope and SIT-vidicon system
at Cerro Tololo Interamerican Observatory. The spectra show H-alpha,
H-beta and He II (468.6 nm) in emission, and strong interstellar Na D
absorption, with relative strengths very similar to those recorded
in the discovery spectra of 1978 May (Grindlay 1979, Ap.J. 232,
L33). The continuum distribution was also very similar, although
0.6 mag brighter, with V ~ 16.3. Additional x-ray and optical observations
are needed to study further transitions in detail and
thereby determine the nature of the system; a binary containing a B
star (ibid.) is now probably excluded.
H. Pedersen, European Southern Observatory, reports further
photometric results of this object (cf. IAUC 3609), obtained with
the Danish 1.5-m telescope at La Silla on June 4.17 UT: V = 15.5,
B-V = +0.8, U-B = -0.1.
SUPERNOVA IN NGC 6946
C. Telesco, E. Becklin, and R. Koehler, University of Hawaii;
and I. Gatley, U.K. Infrared Telescope, telex: "Infrared Telescope
Facility observations of the supernova in NGC 6946 show a large reddening
of the 1-4 um spectrum. With a 10" throw aligned north-south
and a 6" beam, mean colors around June 1 were J-H = +0.2, H-K
= +1.6 and K-L = +2.1, compared to the nearly-Rayleigh-Jeans colors
observed shortly after maximum light in 1980 (Owek et al., in prep.).
These observations may be interpreted in terms of emission from recently
formed dust around the supernova. Further optical and infrared
observations are encouraged."
COMET BOWELL (1980b)
Recent total visual magnitude estimates: May 1.08 UT, 11.5 (J.
E. Bortle, Stormville, NY, 0.32-m reflector); 4.08, 11.5 (Bortle);
8.09, 11.5 (Bortle); 22.25, 11.8 (C. Spratt, Victoria, BC, 0.20-m
reflector); 31.27, 11.9 (Spratt); June 3.11, 11.6 (C. Morris, Harvard,
MA, 0.25-m reflector); 13.29, 11.9 (Spratt).
1981 June 26 (3613) Daniel W. E. Green
Read IAUC 3614
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