Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 5074: 1990V; V404 Cyg

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 5073  SEARCH Read IAUC 5075
IAUC number

                                                  Circular No. 5074
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505

     J. Mueller reports her discovery of a supernova in NGC 7564
(R.A. = 23h13m.1, Decl. = +7 01', equinox 1950.0), located 11".4
east and 16".1 south of the galaxy's center.  The SN appears at mag
about 18 on a blue plate taken July 29 UT with the 1.2-m Oschin
Schmidt telescope in the course of the second Palomar Sky Survey.  A
spectrum (range 380-550 and 590-790 nm) obtained on Aug. 15 by M.
Strauss and S. Strauss on the 5-m Hale Telescope (+ double spectrograph)
shows the presence of broad H-alpha (FWHM about 10 000 km/s)
and H-beta, confirming the object as a type-II SN.

     C. A. Haswell, University of Texas at Austin; and A. W. Shafter,
San Diego State University, communicate:  "We have obtained a
probable determination of the orbital period of V404 Cyg from time-
resolved optical spectra obtained during 1989 July 6.23-6.43 UT
(five weeks after maximum light of the 1989 May outburst) using a
CCD spectrograph at the Cassegrain focus of the McDonald Observatory
2.7-m reflector.  The spectra (range 574.5-714.5 nm, resolution about
0.35 nm) reveal strong (equivalent width about 3.3 nm), single-
peaked H-alpha emission; weak (equivalent width about 0.30, 0.35,
0.25 nm), double-peaked He I 587.6-, 667.8-, and 706.5-nm emission;
and definite (equivalent width about 0.13 nm) Na D 589.0- and 589.6-
nm absorption.  Radial-velocity variations of the H-alpha, the He I
667.8-nm, and the He I 706.5-nm emissions were not detected.  The Na
D absorption lines show a sinusoidal radial-velocity variation,
which, due to blending, induces a spurious signal in the He I 587.6-
nm emission feature.  The velocity of the Na D 589.6-nm component,
which is less contaminated by the He I emission than is the 589.0-nm
component, varies with an amplitude of 74 +/- 9 km/s, and a period
of 0.207 +/- 0.015 day.  The precision of the period determination
is limited primarily by the duration of our observations, which cover
only one cycle of the variation.  V404 Cyg has faded to near its
pre-outburst brightness.  Recent spectroscopy obtained at the Multiple
Mirror Telescope (R. M. Wagner and S. B. Howell, private communication)
failed to reveal any spectral features from the secondary
star.  This suggests that the Na D absorption observed by us over a
year ago originated in the heated face of the secondary star.  In
this case, we identify the period (0.207 +/- 0.015 day) with the
orbital period of the binary, and the amplitude (74 +/- 9 km/s) with a
lower limit on the true K-velocity of the secondary star."

1990 August 15                 (5074)             Daniel W. E. Green

Read IAUC 5073  SEARCH Read IAUC 5075

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!