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IAUC 3591: N CrA 1981; BH CVn (HR 5110 = HD 118216)

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                                                  Circular No. 3591
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


NOVA CORONAE AUSTRINAE 1981
     A. C. Gilmore, Mount John University Observatory, provides the
following precise position, obtained on Apr. 7 (mpg = 7): R.A. =
18h38m33s.6, Decl. = -37o34'09" (equinox 1950.0).  He adds that the object
was not visible on a Damon patrol test plate (limiting magnitude
mpg = 14) obtained on Mar. 31.55 UT by M. Clark.
     I. Busko, F. Jablonski, G. Quast and C. A. 0. Torres, Observatono
Astrofisico Brasileiro, Itajuba, telex: "We obtained a coude
spectrogram of Nova CrA 1981 on Apr. 8.33 UT.  The spectrum (range
390-500 nm, dispersion 0.9 x 10**-6) is similar to that of V1500 Cyg
five days after maximum (Boyarchuk et al. 1977, Soviet Astron. 21,
257).  H-beta has a width of 7.1 nm.  A polarization measurement made
on Apr. 9.24 UT shows percentages of 1.46, 0.75, 0.87 and 0.52 in
the bands U, B, V and R, respectively."


BH CANUM VENATICORUM (HR 5110 = HD 118216)
     P. A. Feldman, Herzberg Institute of Astrophysics, Ottawa, reports
the detection of a large radio outburst from the RS CVn-type
binary HR 5110 = HD 118216 with the 46-m telescope of the Algonquin
Radio Observatory.  The flare was first detected on Apr. 4.36 UT
with a flux density of 250 mJy at 10.46 GHZ.  The radio flare
reached a plateau of ~ 400 mJy at 10.46 GHZ (1.3 x 10**11 J s**-1 Hz**-1)
during Apr. 5.33-5.56, overlapping a three-station Mark III
VLBI-network observation at 5 GHz during Apr. 5.50-5.62.  During Apr.
5.96-6.56 the flux density remained relatively constant at ~ 200
mJy, overlapping a four-station VLBI observation during Apr. 6.00-6.17
and the IUE observations described below.  Several subsequent
measurements by J. M. MacLeod at 10.46 GHZ indicate that the flaring
has continued at the 160-mJy level until at least Apr. 7.50.
     J. L. Linsky, Joint institute for Laboratory Astrophysics, telexes:
"E. Weiler obtained IUE spectra of HR 5110 during Apr. 6.42-6.75
UT.  A 6-hr high-dispersion exposure with the short-wavelength
camera showed exceptionally broad profiles of L-alpha 122 nm, C II
133.4-133.5 nm, C IV 154.8-155.0 nm and He II 164 nm.  The bright emission
lines of L-alpha, C IV and He II are asymmetric, with broad emission
wings extending to longer wavelengths.  These profiles indicate
large line-of-sight motions in the system and probably hot plasma
falling on to one or both stars.  Similar infalling material was indicated
by asymmetric Mg II lines during a flare on UX Ari (Simon
et al. 1980, Ap.J. 239, 911)."


1981 April 10                  (3591)              Brian G. Marsden

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