Central Bureau for Astronomical Telegrams
IAUC 4082: MR Ser; UX Ari; AG Dra
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Circular No. 4082
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 617-495-7244/7440/7444
MR SERPENTIS
K. Mukai, P. A. Charles and N. McPherson, Oxford University,
report: "The AM-Her-type system MR Ser = PG 1550+191 was observed
from La Palma with the 2.5-m Isaac Newton telescope with the Royal
Greenwich Observatory spectrograph and CCD camera during June 4-7.
The average flux density over the wavelength range observed (600-
900 nm) corresponds to R = 16.5, ~ 2 mag fainter than reported by
Liebert et al. (1982, Ap.J. 256, 594), indicating that the system
has entered a low state (see also IAUC 3979). The brightness
variation over the orbital period is also reduced. The spectra
show weak (equivalent width 1.3 nm) H-alpha emission and the absorption
features of an M-type dwarf, although the flux distribution is
flatter than expected from the secondary alone, indicating the
presence of the white dwarf and/or the residual accretion column
at shorter wavelengths. Observers are urged to monitor this
system and, if possible, to measure the white-dwarf temperature
and magnetic field."
UX ARIETIS
P. A. Feldman and P. A. Marshall, Herzberg Institute of
Astrophysics, Ottawa, report a renewal of strong radio flaring from the
RS-CVn binary UX Ari. Measurements at 10.6 GHz with the 46-m
telescope of the Algonquin Radio Observatory on June 29.47 UT yielded
a flux density of 137 +/- 9 mJy, equivalent to a radio luminosity of
5 x 10**10 J s**-1 Hz**-1.
AG DRACONIS
L. Piro, Istituto TESRE, Bologna; A. Cassatella, IUE Observatory,
Villafranca; L. Spinoglio and R. Viotti, Istituto Astrofisica
Spaziale, Frascati; and A. Altamore, Istituto Astronomico,
Rome, telex: "We detected x-ray emission from the high-velocity
symbiotic star AG Dra at minimum phase. The star was observed with
EXOSAT on June 5. Using a bremsstrahlung model with log nH = 20.2,
we find kT = 24 eV and a 0.2-1.0-keV flux of 3.4 x 10**-16 J m**-2 s**-1.
Coordinated IUE observations on June 9 showed an ultraviolet spectrum
typical of minimum phase. There was no ultraviolet contamination
of EXOSAT fluxes. The fine-error-sensor magnitude was 9.8.
Infrared photometry on May 2 and 23 gave: J = 7.12, H = 6.36, K =
6.27, confirming that the K star is substantially stable."
1985 July 17 (4082) Brian G. Marsden
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