Central Bureau for Astronomical Telegrams
IAUC 3345: SS 433; SN IN NGC 3913
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 3346
Circular No. 3345
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
SS 433
B. Margon and colleagues, University of California at Los
Angeles, report that the highly variable x-ray star SS 433 (cf.
IAUC 3314) displays intense emission lines that change their wavelengths
by enormous amounts, up to 1000 A in 50 days. These emissions
have been unambiguously identified as two sets of Balmer and
He I lines, one with large redshift and one with large blueshift,
in addition to a stationary zero-velocity system. Liebert et al.
(preprint submitted to Nature) have independently reached the same
conclusion. Further analysis of nine months of data (many of them
graciously provided by colleagues within the University of California
system) now shows the line motions to recur with period 160 +/- 3
days or an integer multiple thereof. The periodicity appears in all
available data and has therefore persisted for at least parts of 3
cycles. The two systems reached maximum positive and negative
velocities of +50 000 and -30 000 km/s, respectively, on 1978 Nov.
12 +/- 3 - the exact epoch is ambiguous due to the flat-topped nature
of the velocity curves - implying another expected maximum centered
about 1979 Apr. 21 and persisting for about one week. Minimum
velocities of +10 000 and 0 km/s have been observed in the red and
blue systems thus far, but gaps in the data permit the minima to be
deeper, and the two systems may conceivably reverse places in 1979
June, with the redshifted lines acquiring a blueshift and vice
versa. Each of the moving systems normally exhibits broad H-alpha, H-beta,
H-gamma and H-delta emissions, plus often weaker He I 5876 A. The behavior is
so unprecedented that all spectroscopic observers are urged to obtain
as many data as possible on the descending velocity curves in
1979 May and June.
SUPERNOVA IN NGC 3913
F. Ciatti, S. Ortolani, P. Rafanelli and L. Rosino, Asiago
Astrophysical Observatory, write: "Spectrograms were obtained with
the 182-cm telescope on Mar. 27 and 30 and Apr. 1. The spectra
show the characteristics of a type I supernova about 15 days after
maximum, with the strong absorption feature at 6160 A and emission
features at 4210, 4590, 4940, 5190, 5890 and 6320 A. It is very
likely that the supernova attained a maximum of magnitude ~ 13
around Mar. 15. The supernova 1963J in the same galaxy attained
magnitude 13.7 at maximum. Infrared and blue spectra of the new
object taken after Apr. 1 are under reduction."
1979 April 18 (3345) Brian G. Marsden
Read IAUC 3346
Our Web policy. Index to the CBAT/MPC/ICQ pages.
