Central Bureau for Astronomical Telegrams
IAUC 3386: Cen X-4; SN IN NGC 4321
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Circular No. 3386
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
CENTAURUS X-4
S. Wyckoff, Arizona State University, reports that SIT Vidicon
spectra (3350-4750 A, Delta-lambda ~ 5 A) of Cen X-4 were obtained on July 15
with the 400-cm reflector at Cerro Tololo Interamerican observatory.
The observations show weak emission lines of He II, He I and H superimposed
on a strong blue continuum (B ~ 18.5). The spectrum differs
from that of Sco X-1 in that the 4640 A emission features (and
O III 3444 A) are absent, He II 4686 A is very weak and [O III] 4363 A
is moderately strong. The measured emission line widths (FWHM)
were ~ 1200 km/s, and the fluxes were F(H-gamma) ~ 4 x 10**-15 erg cm**-2 s**-1
F_nu(4400 A) ~ 1 x 10**-27 erg cm**-2 s**-1 Hz**-1.
SUPERNOVA IN NGC 4321
T. Barnes, B. Beardsley, T. Moffett, S. Odewahn and G. and A.
de Vaucouleurs, University of Texas at Austin, report the following
definitive reduction of photoelectric observations with the McDon-
aid Observatory 76-, 92- and 205-cm reflectors:
1979 UT V B-V U-B V-R R- I
May 21.13 12.96 +0.63: +0.55 +0.12:
22.15 12.96 +0.64 +0.56 +0.21
23.14 12.97 +0.70 +0.59 +0.20
23.14 12.97 +0.64 +0.01
24.14 13.07 +0.69 +0.59 +0.18
27.20 13.26 +0.68 +0.05
28.19 13.29 +0.71 +0.07
29.15 13.34 +0.72 +0.08
30.15 13.39 +0.74 +0.05
31.15 13.50 +0.71 +0.06
A faster linear decay of the V magnitude (0.066 magnitude per day)
and a halt in the reddening began on May 22 or 23.
K. Kaila, Vantaa, Finland, reports that further analysis of
his prediscovery observations of this object on Apr. 15.9 UT (cf.
IAUC 3359) yields B ~ 11.6, V ~ 11.2.
The following visual magnitude estimates have been reported:
June 24.29 UT, 14.4 (J. Sanford, Orange, CA); 26.09, 14.7 (J.
Bortle, Brooks Observatory); 27.12, 14.8 (Bortle).
1979 July 27 (3386) Daniel W. E. Green
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