Central Bureau for Astronomical Telegrams
IAUC 2827: N Cyg 1975
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 2828
Circular No. 2827
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS
NOVA CYGNI 1975
A cablegram from the Torun Observatory describes the spectrum
on Aug. 29.9 UT as showing wide, shallow hydrogen lines displaced
to the violet against interstellar H and K by about 1000 km/s.
D. J. Stickland, Royal Greenwich Observatory, cables that
spectrograms at 10 and 20 A/mm dispersion taken on Aug. 30.00 UT
show a strong ultraviolet continuum with possible broad, faint
hydrogen-line emission; there were also strong, sharp H, K and D
lines.
O. Dobrovol'skij, Institute of Astrophysics, Dushanbe, cables
that on Aug. 30.6 UT Yu. V. Borisov observed the Balmer lines in
emission; there were also dark components.
G. Wallerstein, Department of Astronomy, University of Washington,
reports that the spectrum on Aug. 31.3 UT showed hydrogen
emission, with absorption indicating an expansion of 2500 km/s.
There was strong interstellar Ca II. He adds that the object is
probably a very fast nova then just past maximum.
J. S. Neff, Department of Physics and Astronomy, State University
of Iowa, reports that the spectrum on Sept. 1.1 UT showed a
fairly strong ultraviolet continuum and Balmer emission lines.
J. Horn, F. Zdarsky and S. Kriz, Astronomical Institute, Ondrejov,
communicate: "Eight spectra were taken between Aug. 29.93
and 30.11 UT with the coude spectrograph of the 200-cm telescope at
dispersions of 4.2 to 17.2 A/mm and covering the range 3400-6900 A.
The continuum was very strong, also in the extreme violet and red. H-alpha,
H-beta and Fe II displayed very broad emissions. H-alpha and He I 6678 A
had three broad absorptions at -500, -1200 and -2000 km/s, while
other hydrogen lines had single broad absorptions at -1300 km/s.
Sharp, strong interstellar H, K and D lines had almost zero residual
intensities. Seven spectra between Aug. 31.81 and 31.99 were
dominated by many very broad and intense emission lines, especially of
H-alpha to H-epsilon, Fe II, O I and Ca II. Strong absorption lines
exhibited a velocity of about -2000 km/s."
A cablegram from the Wise Observatory mentions that visual
examination of the Balmer absorption shift on Aug. 29.9 UT [or Aug.
30.9 UT?] gave a velocity of about 3000 km/s; it is suggested that
the object is possibly a galactic supernova of type II.
1975 September 2 (2827) Brian G. Marsden
Read IAUC 2828
Our Web policy. Index to the CBAT/MPC/ICQ pages.
