Central Bureau for Astronomical Telegrams
IAUC 3366: HR 5110 = HD 118216; NOVALIKE OBJECT IN Cen
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Circular No. 3366
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
HR 5110 = HD 118216
P. A. Feldman, Herzberg Institute of Astrophysics, reports the
detection of a large radio outburst from the RS-CVn-binary HR 5110 =
HD 118216 with the 46-m telescope of the Algonquin Radio Observatory.
The flare was first detected on May 29d08h26m UT with a flux
density of 425 mJy at 10.76 GHz. Measurements made over the next
two days have shown continued flaring activity in the range 0.20-0.35
Jy. Observations at radio, optical, ultraviolet, and x-ray
wavelengths are urged.
J. L. Linsky, University of Colorado, reports: "We obtained
International Ultraviolet Explorer spectra of HR 5110 on May 31 at
17h00m UT. A 30-min low-dispersion exposure with the short-wavelength
camera on IUE shows strong emission lines at L-alpha 1216 A, N V
1240 A, O I 1304 A, C II 1335 A, O V 1370 A, Si IV 1400 A, C IV 1550 A,
and He II 1640 A. This high-excitation spectrum indicates material
at temperatures up to 250 000 K, which is likely produced at the
secondary star of the system." He adds that the Algonquin Radio
Observatory reported the 10.76-GHz flux as 215 mJy on May 31d08h36m.
NOVALIKE OBJECT IN CENTAURUS
M. Oda, Observing Team of Hakucho, University of Tokyo, communicates:
"While observing the x-ray nova in Centaurus (cf. IAUC 3360,
3362) with rotating modulation collimators on Hakucho (Corsa-B), an
extremely intense x-ray burst was recorded at May 31d14h09m29s UT
from this source. The burst intensity was ~ 40 times Crab strength
in the range 1-12 keV. The time profile is similar to a type I
burst event, with risetime < 1 s, decay time several seconds, and
softening in the tail. The steady component of Cen X-4 was at
about the Crab level both prior to and after this outburst."
W. Liller, Center for Astrophysics, reports that he has made
a search for earlier outbursts of the Cen-4 optical candidate in
the archival collection of photographs stored at the Harvard College
Observatory. No outbursts were found on plates taken from
1889 to 1951, in 1970-71, 1978 and 1979 Jan. The limiting magnitude
of the plates ranges from B = 13.5 before 1900 to B = 16.0 for
the modern plates. Thus there is no demonstrable similarity to the
recurrent nova idertified with the x-ray transient A0620-00.
Corrigendum. On IAUC 3362, line 4, the all-sky monitor position
should read Decl. = -32o.2, rather than -32o.8.
1979 June 4 (3366) Daniel W. E. Green
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