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Record Details

Record 54 of 515
Optical Studies of Active Comets
Offline Availability: Go to Request Form
Author and Affiliation:
Jewitt, David(Hawaii Univ., Inst. for Astronomy, Honolulu, HI United States)
Abstract: This grant was to support optical studies of comets close enough to the sun to be outgassing. The main focus of the observations was drawn to the two extraordinarily bright comets Hyakutake and Hale-Bopp, but other active comets were also studied in detail during the period of funding. Major findings (all fully published) under this grant include: (1) Combined optical and submillimeter observations of the comet/Centaur P/Schwassmann-Wachmann 1 were used to study the nature of mass loss from this object. The submillimeter observations show directly that the optically prominent dust coma is ejected by the sublimation of carbon monoxide. Simultaneous optical-submillimeter observations allowed us to test earlier determinations of the dust mass loss rate. (2) We modelled the rotation of cometary nuclei using time-resolved images of dust jets as the primary constraint. (3) We obtained broad-band optical images of several comets for which we subsequently attempted submillimeter observations, in order to test and update the cometary ephemerides. (4) Broad-band continuum images of a set of weakly active comets and, apparently, inactive asteroids were obtained in BVRI using the University of Hawaii 2.2-m telescope. These images were taken in support of a program to test the paradigm that many near-Earth asteroids might be dead or dormant comets. We measured coma vs. nucleus colors in active comets (finding that coma particle scattering is different from, and cannot be simply related to, nucleus color). We obtained spectroscopic observations of weakly active comets and other small bodies using the HIRES spectrograph on the Keck 10-m telescope. These observation place sensitive limits to outgassing from these bodies, aided by the high (40,000) spectral resolution of HIRES.
Publication Date: Jan 01, 1998
Document ID:
20000021125
(Acquired Mar 10, 2000)
Subject Category: ASTROPHYSICS
Coverage: Final Report; 1 Apr. 1995 - 31 Mar. 1998
Document Type: Technical Report
Contract/Grant/Task Num: NAGW-4601
Financial Sponsor: NASA; Washington, DC United States
Organization Source: Hawaii Univ.; Inst. for Astronomy; Honolulu, HI United States
Description: 3p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: OPTICAL ACTIVITY; COMETS; RESEARCH; HALE-BOPP COMET; SUBMILLIMETER WAVES; MASS TRANSFER; DUST; LOSSES; SPACE OBSERVATIONS (FROM EARTH); VISUAL OBSERVATION; ASTEROIDS; BROADBAND; CARBON MONOXIDE; COMET NUCLEI; CONTINUUMS; EPHEMERIDES; HIBERNATION; IMAGES; OUTGASSING; ROTATION; SPECTRAL RESOLUTION; SPECTROSCOPY
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