Accession Number:

ADA171510

Title:

The Hydrogen Coma of Comet Halley Before Perihelion: Preliminary Observations with Dynamics Explorer 1,

Descriptive Note:

Corporate Author:

IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s):

• Craven,J. D.
• Frank,L. A.
• Rairden,R. L.
• Dvorsky,M. R.

Report Date:

1986-02-01

Pagination or Media Count:

17.0

Abstract:

The hydrogen coma of Comet Halley has been observed in resonantly scattered solar Lyman-alpha radiation during the period 1-29 January 1986 as the comet approached perihelion. These observations were obtained with the imaging photometer for vacuum-ultraviolet wavelengths on the spacecraft Dynamics Explorer 1. For the initial analysis of observations available in 17 orbits distributed throughout the period, least-squares fits are computed for the observed exponential decrease in brightness with radial distance from the nucleus. Brightness at the nucleus increased from approx. 3 to 17 kR during the observing period. Preliminary analysis yields water production rates of approx. 3.6 x 10 to the 29th power and 1.9 x 10 to the 30th power moleculessec on 1 and 29 January, respectively.

Descriptors:

• *COMETS
• *NEBULAE
• IMAGE PROCESSING
• OBSERVATION
• RESONANCE SCATTERING
• HYDROGEN
• BRIGHTNESS
• SUBLIMATION
• SOLAR RADIATION
• RANGE(DISTANCE)
• NUCLEI
• PHOTOMETRY
• PERIHELION
• SCIENTIFIC SATELLITES
• PHOTOMETERS

Subject Categories:

• Astronomy
• Astrophysics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE