The production and spatial distribution of neutral and ionized water vapor in Comet P/Halley

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6697977

Disanti, M A

The problem of water vapor production and distribution in comet P/Halley is addressed. The data was acquired using the Lunar and Planetary Laboratory charge-coupled device (CCD) on the 154 cm Catalina telescope of the University of Arizona Observatories. The data acquisition system was employed in two modes. The long-slit spectroscopy mode covered the wavelength range 5200 to 10400 A. The narrow band filter imaging mode allowed two-dimensional mapping of selected cometary emission features. The 1986 March 5 long-slit spatial profiles showed a central dip in the water ion (H2O+) column density, of order 30 percent in the inner coma, which filled in farther tailward. Vega-1 spacecraft measurements (March 6) revealed a decrease in local ion density, of roughly 60 percent at closest approach R is approximate or equal to 9000 km sunward of the nucleus, relative to an inbound maximum R is approximate or equal to 12000 km. Our filter images (March 6), centered on the H2O+ 0, 8, 0 band, showed that the falloff in ions was relatively rapid sunward of the nucleus. In the anti-solar direction the decrease was much more gradual, due to the solar wind sweeping ions from the head of the comet into the plasma tail, whose width was of order 10(exp 5) km in the inner coma, diverging slowly and breaking up into a ray pattern farther tailward. The distribution of neutral water was mapped out using the O I wavelength 6300 emission as diagnostic probe. In contrast to the ions, the H2O molecules were confined mainly to the inner few x 10(exp 4) km of the coma.

• Research Organization: Arizona Univ., Tucson, AZ (USA)
• OSTI ID: 6697977
• Resource Relation: Other Information: Ph.D. Thesis
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HALLEY COMET
WATER VAPOR
CHARGE-COUPLED DEVICES
EXPERIMENTAL DATA
ION DENSITY
MOLECULES
SOLAR WIND
SYMMETRY
COMETS
DATA
FLUIDS
GASES
INFORMATION
NUMERICAL DATA
SEMICONDUCTOR DEVICES
SOLAR ACTIVITY
VAPORS
640107* - Astrophysics & Cosmology- Planetary Phenomena