NOAO > Observing Info > Approved Programs > 2005B-0490
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NOAO > Observing Info > Approved Programs > 2005B-0490 |
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PI: Yanga Fernandez, University of Hawaii, yan@ifa.hawaii.edu
Address: Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822, U.S.A.
CoI: Stephen Lowry, Queen's University - Belfast
CoI: Beatrice Mueller, NOAO
CoI: Nalin Samarasinha, NOAO
CoI: Michael A'Hearn, Univ of Maryland
CoI: Tony Farnham, Univ of Maryland
Title: Search for Secular Drift in the Rotation of Comet 2P/Encke
Abstract:
We propose to determine if and how the rotation state of Comet
2P/Encke changes from orbit to orbit. Time series of photometry in
2005, while the comet is near aphelion, will indicate if the dominant
periodicity has changed from that measured around the previous aphelion,
in 2001-2002. While it is possible that the comet is in non-principal
axis rotation, one phenomenon that could also be present in the data is
a secular drift of the rotation period caused by outgassing torques.
The comet's emission of gas can provide a reaction force that could be
spinning up the nucleus. Such a phenomenon must be taken into account
if we are to understand P/Encke's rotation state. Furthermore this
could be used to derive the comet's mass and density, fundamental
properties that are poorly constrained among cometary nuclei.
Comparison of data from the 1980s and the early 2000s suggests that the
dominant periodicity is decreasing by about 2.4 minutes per orbit, but
we need much more detailed coverage than what was obtained in the 1980s
to be confident of this phenomenon's reality and magnitude.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2005B-0490 |
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