Central Bureau for Astronomical Telegrams
IAUC 5585: (4015)
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Circular No. 5585
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
(4015) 1979 VA = COMET WILSON-HARRINGTON (1949 III)
In the course of examining the Palomar Sky Survey for
prediscovery images of minor planets, E. Bowell, Lowell Observatory,
identified trails of the borderline Apollo object (4015) 1979 VA on
the 12-min blue and 45-min red plates of 1949 Nov. 19.1 UT.
B. A. Skiff found that, to a limiting surface brightness of B about 25
mag/square arcsec, a very slightly fanned tail of length 2'.8 is
clearly visible on the blue print at p.a. 90 +/- 5 deg, the antisun
direction being at p.a. 76 deg. The peak apparent surface brightness,
near the trailed image of the nucleus, is about 23 mag/square arcsec.
The red Sky Survey image shows a very faint tail of maximum surface
brightness 24 mag/square arcsec. The nuclear magnitude is near
13.5-14.0 on both prints. R. M. West, H.-H. Heyer and J. Quebatte,
European Southern Observatory, report that photographic enhancements
of glass copies of the Sky Survey plates confirm that the tail feature
is definitely present and attached to the trails over their full
length and apparently does not extend beyond the trail ends; there is
a gap of 9 min between the two exposures. The undersigned points
out that the 1949 object was in fact (periodic) comet Wilson-
Harrington (1949g = 1949 III), discussed in a report by L. E.
Cunningham on IAUC 1250 as having been entirely asteroidal in
appearance on further Palomar Schmidt exposures through Nov. 25. The
nominal 2.3-year orbital period, noted at the time as being very
uncertain, was later invalidated by the need to correct the time of
the Nov. 22 exposure by -1 hour (see MPC 16653). The following
1949-epoch osculating elements are from an orbit solution using 66
observations in 1949, 1979-80, 1988-89 and 1992:
Epoch = 1949 Oct. 11.0 TT
T = 1949 Oct. 8.0799 TT Peri. = 81.0722
e = 0.620102 Node = 279.9955 2000.0
q = 1.003941 AU Incl. = 2.8102
a = 2.642657 AU n = 0.2294262 P = 4.296 years
No cometary emission was noted during the well-observed
1979-80 apparition. Recent spectroscopy by S. J. Bus, Lowell
Observatory, using the Ohio State University CCD spectrograph at the
1.8-m Perkins reflector, has again shown no cometary emission and
indicates the object to be neutral in color to within a few percent
per 100 nm over the range 400-640 nm, in agreement with UBV color
indices measured by A. W. Harris and R. L. Millis in 1979 (IAUC 3426;
Harris and Young 1983, Icarus 54, 59).
1992 August 13 (5585) Brian G. Marsden
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