Central Bureau for Astronomical Telegrams
IAUC 4671: EXO 032957-2606.9; 1987A
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Circular No. 4671
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
EXO 032957-2606.9
K. Beuermann and H.-C. Thomas, Max Planck Institut fuer Physik
und Astrophysik, Garching; and P. Giommi and G. Tagliaferri, EXOSAT
Observatory, ESTEC, Noordwijk, write: "We report the identification
of a serendipitous EXOSAT source (R.A. = 3h29m57.0, Decl. = -26 06'56",
equinox 1950.0) with a probable long-period, AM Her-type binary.
Spectrophotometric observations with the ESO/MPI 2.2-m telecope at La
Silla yielded a spectroscopic period of 228 +/- 1 min (1-sigma error).
The system displays strong emission lines of H, He I, and He II,
asymmetric line profiles with blue wings extending to 1000 km/s, and
a radial-velocity amplitude of only 63 km/s. The 400-1000-nm flux
shows no obvious orbital variation, suggesting the absence of strong
cyclotron emission. The secondary star was detected by its TiO bands
and is approximately of spectral type dM4. The x-ray source is
comparatively faint and varied by at least a factor of 10 between
1983 and 1986. The folded x-ray light curve in the 1986 high state
is consistent with being flat and the spectrum is very soft (blackbody
temperature kT < 30 eV). We suggest that EXO 032957-2606.9 is an AM
Her-type binary with a small orbital inclination. The prime accreting
pole is permanently hidden from view and the variable soft x-ray flux
originates from the second pole which is always in view. Systems with
such geometry are expected to exist and EXO 032957-2606.9 would be the
first to be identified."
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
D. E. Jennings, Goddard Space Flight Center (GSFC), NASA; R. J.
Boyle, Dickinson College; and G. R. Wiedemann and S. H. Moseley, GSFC,
report: "Observations of SN 1987A were made on Oct. 25, 26, and 27
using the Goddard 10-micron cryogenic grating spectrometer on the 4-m
telescope at Cerro Tololo Interamerican Observatory. The spectral
resolving power was about 1000 and the field-of-view was 2".5. Three
lines were recorded, at 10.5, 11.3, and 17.9 microns (normally identified
as Co II, H 9-7, and Fe II, respectively). The lines were fully
resolved. Preliminary results show the continuum to be about 9 Jy at
10.5 and 11.3 microns, and 4 Jy at 17.9 microns. The 10.5-micron line
is barely visible, about 1 Jy above the continuum. The 11.3- and 17.9-
micron lines are 5 and 10 Jy above the continuum, respectively. All
three lines are about 3000 km/s wide at half maximum with a 500-700 km/s
redshift of the emission centroid."
1988 November 4 (4671) Daniel W. E. Green
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