Central Bureau for Astronomical Telegrams
IAUC 5898: (2060)
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Circular No. 5898
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)
(2060) CHIRON
M. W. Buie, Lowell Observatory, reports: "The stellar occultation
candidate Ch02, identified by Bus et al. (1993, submitted to
A.J.), was predicted by C. Olkin, S. McDonald, C. Ford, J. Foust,
L. Sopata, and J. L. Elliot with sufficient accuracy that observations
by four teams were successful in observing the occultation by
(2060) Chiron on Nov. 7. These teams were manned by the University
of Arizona, Massachusetts Institute of Technology, Ames Research
Center, NASA, and Lowell Observatory at the following locations:
Tierra Del Sol, CA (R. Marcialis and R. Hill); Palomar Mountain (S.
Bus and R. Meserole); Ojai, CA (L. Wasserman and J. Spencer); and
Table Mountain (E. Dunham, M. Buie, and J. Young). J-band images
were also obtained around the time of the event by T. H. Jarrett,
C. A. Beichman, and T. Herter using the Palomar Prime Focus Infrared
Camera on the 5-m Hale Telescope. The flux of the star was
seen to drop by 80 percent for 7 s at the Tierra Del Sol site. The
observation is consistent with a single chord, placing a lower
bound of 166 km for the diameter of Chiron. However, this
interpretation requires that the star be an unresolved double of which
only one component was occulted by Chiron. Preliminary spectra
from the Perkins 1.8-m telescope do not confirm the duplicity of
the star, but the results are not yet conclusive. Each of the
other sites noted shallower unresolved dips that decrease in
strength with increasing distance from Chiron and occur at nearly
the same time, but they are inconsistent with chords from a solid
surface occultation. These dips may be due to larger-than-average
noise, or to an occultation by a narrow (< 10 km) dust jet."
C. Telesco, Marshall Space Flight Center, NASA; B. Schulz,
ESTEC, European Space Agency; and H. Campins and D. Osip, University
of Florida, communicate: "We report 10- and 20-micron detections
of (2060) Chiron obtained on Nov. 22 UT at the NASA Infrared
Telescope Facility with the MSFC 20-pixel bolometer array (pixel
size: R.A. x Decl. about 4".3 x 4".2) during exceptionally good
atmospheric conditions. The following flux densities do not include
color corrections due to the low temperature of Chiron: Nov.
22.6217-22.6388, 20 +/- 5 mJy at 10.8 microns (Delta lambda = 5.3
microns; this is the first detection of Chiron at this wavelength);
Nov. 22.6425-22.6492, 310 +/- 61 mJy at 19.2 microns (Delta lambda
= 5.2 microns). Uncertainties in absolute calibration, which are
not included above, should not exceed 10 percent."
1993 November 29 (5898) Daniel W. E. Green
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