Central Bureau for Astronomical Telegrams
IAUC 4210: 1986G; AM CVn; VY Aqr
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Circular No. 4210
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
SUPERNOVA 1986G IN NGC 5128
M. W. Feast, South African Astronomical Observatory, reports
the following optical photometry on May 5 by P. W. Hill with the
1.0-m reflector and infrared photometry by R. S. Stobie with the
1.9-m reflector: V = 11.88, B-V = +0.98, U-B = +0.52, J = 10.08, H
= 9.95, K = 9.89. A spectrum obtained on May 6 by A. Fairall
shows the supernova to be of type I.
M. Phillips, Cerro Tololo Interamerican Observatory, telexes:
"Spectra obtained during May 5-7 by J. Tonry and M. Strauss show
that the supernova is of type I and approaching maximum. Strong
interstellar Na I D absorption is present, at the redshift of NGC
5128, indicating that the supernova is substantially reddened by
the dust lane. A higher resolution spectrum taken by S. Heathcote,
A. Cowley and J. Hutchings shows strong interstellar Ca II H and K
absorption with a complicated profile, including a weaker component
that may be due to our own Galaxy. Photometry obtained by D.
Geisler and myself indicates that the supernova was slowly increasing
in brightness during May 5-7. Observations made on May 7.05
UT yield approximate magnitude and color V = 11.71, B-V = +1.01."
AM CANUM VENATICORUM
U. R. Rao and his team, Indian Space Research Organization,
Bangalore, report: "The ultrashort-period interacting binary AM
CVn was detected in an extremely active state on Feb. 7. An outburst
brightening by 1.1 mag in white light at 21h15m UT lasted for
a complete orbital (?) period of 1051 s and showed the
characteristic double-humped structure. This is the largest flaring
activity so far reported on this normally quiescent object. We
had reported earlier a smaller flare brightening of 0.34 mag in
1985. Photometric observations were made with a GAAS phototube
attached to the 1-m reflector at the Vainu Bappu Observatory,
Kavalur. We urge observers to continue photometric monitoring of
this object using flat response tubes."
VY AQUARII
J. Mattei, AAVSO, communicates the following magnitude estimates
by R. Harvan, Ridge, MD: May 4.39 UT, 10.3; 5.39, 10.3. She
stresses the need for high-speed photometry of possible superhumps.
1986 May 8 (4210) Brian G. Marsden
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