Central Bureau for Astronomical Telegrams
IAUC 5243: N Oph 1991; NEPTUNE I (TRITON)
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Circular No. 5243
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
NOVA OPHIUCHI 1991
R. M. Wagner, Ohio State University; and S. G. Starrfield, Arizona
State University, report: "Optical spectra of the variable object
in Ophiuchus (cf. IAUC 5238, 5240) corresponding with the accurate
position reported on IAUC 5241 were obtained on Apr. 18.48 UT
with the Perkins 1.8-m telescope and CCD spectrograph (range 440-700
nm, resolution 1 nm). The spectrum shows strong emission lines due
to H-alpha, H-beta, Fe II, He I (587.6 nm), Na I, Si II (598.0 nm),
and N II. The FWHM width of H-alpha emission is about 2300 km/s.
The He I 587.6-nm and Na D blend exhibits a P-Cyg profile. The
spectrum is that of a classical nova and appears to resemble the
spectrum of Nova Vul 1987 (QV Vul) early in its outburst."
A. C. Gilmore provides the following photometric measurements
made with 0.6-m Cassregrain reflector at Mt. John University
Observatory: Apr. 16.67 UT (good observing conditions), V = 10.68 +/-
0.02, U-B = 0.0 +/- 0.1, B-V = +0.96 +/- 0.02, V-R = +0.86 +/- 0.01,
V-I = +1.62 +/- 0.04; Apr. 17.68 (marginal conditions), 10.71 +/-
0.04, -0.01 +/- 0.1:, +0.89 +/- 0.02, +0.88 +/- 0.02, +1.52 +/- 0.07.
NEPTUNE I (TRITON)
L. H. Wasserman, Lowell Observatory; D. Mink, Harvard-Smithsonian
Center for Astrophysics; and A. Klemola, Lick Observatory,
communicate: "A search for close appulses involving Triton and stars
near the path of Neptune has been performed. The star positions
were measured on plates taken with the Lick 0.51-m Carnegie double
astrograph. The Jet Propulsion Laboratory NAIF ephemeris of Triton
was used in computing the appulses. Seven close appulses occurring
between 1991 July 9 and Aug. 4 were identified. The predicted
separations of Triton and the stars at closest approach are small enough
that, within the uncertainties of the astrometry and the ephemeris,
actual occultations could occur. All seven appulses take place with
Neptune high in the sky over sites populated by major telescopes.
With one exception, the stars involved in these appulses are near mv
= 15. However, on July 31, Triton is predicted to pass within 0".5
of a star for which V = 11.4 and B-V = +1.2. This appulse will be
visible from Western Australia, India, Africa, and the Middle East.
Individuals interested in receiving details about these potential
occultations should contact Dr. Lawrence Wasserman, Lowell Observatory,
1400 W. Mars Hill Rd., Flagstaff, AZ 86001, U.S.A. (e-mail
SPAN address PERCY::LHW)."
1991 April 18 (5243) Daniel W. E. Green
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