Central Bureau for Astronomical Telegrams
IAUC 8816: 2004 PB_108, (60621) 2000 FE_8; C/2006 P1
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Circular No. 8816
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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2004 PB_108 AND (60621) 2000 FE_8
K. S. Noll, Space Telescope Science Institute (STScI); W. M.
Grundy, Lowell Observatory; S. D. Kern, STScI; H. F. Levison,
Southwest Research Institute; and D. C. Stephens, Brigham Young
University, report the detection of binary companions to two
additional transneptunian objects: 2004 PB_108 (cf. MPECs 2004-R17;
MPO 86538) and (60621) 2000 FE_8 (cf. MPECs 2000-F46; MPO 110654).
Both were found on images obtained with the High Resolution Camera
of the Advanced Camera for Surveys on the Hubble Space Telescope,
using the clear filters with one 300-s exposure at each of four
dithered positions on the detector. The observations of 2004
PB_108 were made during 2006 Aug. 4.300-4.377 UT; its two
components were separated by an angular distance of 0".172 +/-
0".003 and differ in brightness by 1.2 mag, with the fainter
component lying at a position angle of 298 +/- 2 deg from the
primary (the projected separation of the objects in the sky plane
is 5320 +/- 90 km). The observations of (60621) were made during
2007 Jan. 15.066-15.091; its two components were separated by an
angular distance of 0".044 +/- 0".003 and differ in brightness by
0.6 mag, the fainter component lying at a position angle of 187 +/-
11 deg from the primary (the projected separation of the objects in
the sky plane is 1180 +/- 80 km).
COMET C/2006 P1 (McNAUGHT)
N. Dello Russo, R. J. Vervack, Jr., H. A. Weaver, and C. M.
Lisse, Applied Physics Laboratory, Johns Hopkins University,
report the detection of parent volatiles in comet C/2006 P1 on Jan.
27 (r = 0.55 AU, Delta = 1.05 AU, geocentric velocity = +38.2 km/s)
using the NASA Infrared Telescope Facility (+ CSHELL). The
following species were detected: H_2O, CO, CH_4, HCN, C_2H_2,
C_2H_6, NH_3, H_2CO, CH_3OH, NH_2, and OH. For an aperture of size
1" x 3" centered on the nucleus, they obtained the following line
fluxes (x 10**-18 W m**-2) for representative emission lines: H_2O
[(nu)_3-(nu)_2 2_(20)-2_(21)], 60; CO (1-0 R0), 20; CH_4 [(nu)_3
R0], 9.8; HCN [(nu)_3 R6], 19; C_2H_2 [(nu)_3 R3], 15; C_2H_6
[(nu)_7 **RQ_0], 38; NH_3 [(nu)_1 aqQ(3,3)], 10; H_2CO [(nu)_1,
several blended lines at 2781 cm**-1], 11. The continuum flux
densities [x 10**-15 W m**-2 (cm**-1)**-1] within the above
aperture were 1.2, 1.7, 2.1, and 7 at 3.02, 3.30, 3.59, and 4.69
microns, respectively. Preliminary results are given assuming a
rotational temperature of 150 K for all species. The H_2O
production rate was 1.7 x 10**30 molecules/s, and the abundances
relative to H_2O were as follows: CO, 2 percent; CH_4, 0.45
percent; C_2H_6, 0.45 percent; C_2H_2, 0.5 percent; H_2CO, 0.5
percent; NH_3, 2 percent; HCN, 0.25 percent.
(C) Copyright 2007 CBAT
2007 March 3 (8816) Daniel W. E. Green
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