Central Bureau for Astronomical Telegrams
IAUC 3986: PLUTO; 1976 XV = 1984m
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 3987
Circular No. 3986
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
PLUTO
E. K. Hege and J. Drummond, Steward Observatory, write that a
well-calibrated speckle interferometric observation made on Feb.
16.44 UT with the Harvard speckle camera at a single 1.8-m mirror
of the Multiple Mirror Telescope showed the satellite 1978 P1 to
be separated from the primary by 0"168 +/- 0"01 in p.a. 17.8 +/- 3 deg.
The prediction by Harrington and Christy (1981, A.J. 86, 442) gave
separation 0"36 in p.a. 7.3. The discordance in position angle
confirms that found earlier (Hege et al. 1982, Icarus 50, 72) and
shows the satellite's orbital inclination (with respect to the
plane of the sky) to be 94 +/- 1 deg, a decrease of 1 +/- 1 deg over the
prediction (and in contrast to a 3 +/- 4 deg increase over prediction
observed in 1980 June). This suggests that the expected eclipses
of the system should be occurring when Pluto next becomes
favorably placed, although events may be delayed by ~ 4 hr.
PERIODIC COMET SCHAUMASSE (1976 XV = 1984m)
J. Gibson reports his recovery of this comet as shown below.
The indicated correction to the prediction on MPC 7660 is Delta-T =
-0.10 day. The recovery appears to confirm a single, hitherto
unreported, observation of the comet by E. Roemer at the 1976 return
(at Delta-T = -0.03 day from the corresponding prediction).
UT R.A. (1950.0) Decl. m2 Observer
1976 Dec. 27.54146 15 48 59.03 -14 06 42.4 18.5 Roemer
1984 Sept. 5.48613 6 43 01.85 +20 42 28.2 19 Gibson
6.47909 6 46 10.85 +20 44 06.5 "
E. Roemer (Steward Observatory, Kitt Peak Station). 2.3-m reflector.
The comet's image is a faint smudge, weak and diffuse in
poor seeing at low altitude.
J. Gibson (Palomar Mountain Observatory). 1.2-m Schmidt telescope.
Stellar condensation with very weak coma.
Computations by the undersigned show that linkage of the
1959-1960, 1976 and 1984 observations can be accomplished using
the nongravitational parameter A2 = -0.051. This compares with A2
= -0.038 during 1911-1928 and A2 = -0.041 during 1944-1960.
1984 September 12 (3986) Brian G. Marsden
Read IAUC 3987
Our Web policy. Index to the CBAT/MPC/ICQ pages.
