NOAO > Library > NOAO Preprint Series > Preprint 900
|
NOAO > Library > NOAO Preprint Series > Preprint 900 |
|
Author(s): Samarasinha, N.H., and Mueller, B.E.A.
Title: Spin Axis Direction of Comet
19P/Borrelly Based on Observations
from
2000 and 2001
Abstract:
We calculate the direction of the rotational angular momentum vector, M, of
comet 19P/Borrelly based on rotational lightcurve data from 2000, groundbased
imaging of the coma during the Deep Space 1 encounter, and the basic
near-nucleus coma morphology as revealed by the Deep Space 1 spacecraft. For
the most likely direction, we derive a family of solutions (with center at
RA=221\deg, Dec = -7\deg) if the direction of M is towards the sunward
hemisphere during the Deep Space 1 encounter, whereas if the rotation is of
opposite sense, the diametrically opposite family of solutions (with center at
RA=41\deg,
Dec=7\deg) would result. We argue that the coma morphology in September 2001
is
consistent with the nucleus being a principal axis rotator or one
observationally indistinguishable from it. Therefore, for all practical
purposes, the direction of the rotational angular momentum vector coincides
with
the spin axis. We also discuss why the determination of the spin axis
direction
based on observations from the last apparition is in disagreement with the
current result.
Date Received:
June 11, 2002
Publication Info:
Earth, Moon and Planets 90(1):473-482
Downloadable version (3601 Kb PDF)
|
NOAO > Library > NOAO Preprint Series > Preprint 900 |
|