Central Bureau for Astronomical Telegrams
IAUC 4622: 1987g; AS 296
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Circular No. 4622
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
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
PERIODIC COMET TEMPEL 2 (1987g)
M. A'Hearn, P. Feldman, E. Roettger, and D. Schleicher report
gaseous production rates, contemporaneous with the nuclear measurements
reported on IAUC 4614: "Measurements with the International
Ultraviolet Explorer (IUE) on June 10.4 UT imply a water production
of 1.3 x 10E27 s-1 (vectorial model), while measurements with the
University of Hawaii 2.24-m telescope on June 11.5 imply a water
production of 3 x 10E27 s-1. The IUE value has an uncertainty of +/-
30 percent due to accumulated errors in the blind offset tracking.
The ground-based measurements have a large uncertainty due to
extinction. It is not known whether the variation is part of the
secular turn-on expected at this time for this comet or a short-term
fluctuation. The area of the nucleus found on IAUC 4614 implies
that < 0.1 percent of the surface is active. Production of CN and
C2 on June 11.5 was 3 x 10E24 and 2 X 10E24 s-1, respectively,
somewhat lower than 'typical' relative to H2O. The uncertainty in C2
is very large due to continuum subtraction."
Total visual magnitude estimates (cf. IAUC 4606): June 4.28
UT, 13.1 (C. S. Morris, Whitaker Peak, CA, 0.26-m reflector); 11.24,
13.1 (E. A. Jacobson, Evansville, MN, 0.25-m reflector); 13.25,
13.5: (D. Levy, Mt. Lemmon, AZ, 1.5-m reflector; highly condensed);
July 3.22, 13.8 (A. Hale, Las Cruces, NM, 0.41-m reflector).
AS 296
U. Munari, Asiago Astrophysical Observatory, telexes: "An
outburst of the symbiotic star AS 296 was discovered on June 30, on
the TV screen of the echelle spectrograph at the Asiago 1.8-m
telescope. With the same device on May 30, and during the previous two
years, the star had appeared normal (usually around magnitude B =
13.9 during quiescence). A Schmidt camera plate obtained on July 4
under poor atmospheric conditions gives B = 10.0 +/- 0.5. A low-
dispersion spectrum, secured by T. Iijima on July 3, shows remarkable
changes relative to the quiescent state. The He II emission
at 468.6 nm has disappeared, while the absorption spectrum of the
M giant has been overwhelmed by a blue continuum. Only the Balmer
series and He I (587.6 nm) appear in emission. The H-alpha profile in
the June 30 echelle spectrum shows a double-peaked profile with V/R
= 0.3, which does not look too different from the profiles secured
in the past two years."
1988 July 5 (4622) Daniel W. E. Green
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