Solar cycle study of interplanetary Lyman-alpha variations - Pioneer Venus Orbiter sky background results

Journal Article · Mon Jun 01 04:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165345· OSTI ID:6119503

Ajello, J M; Stewart, A I; Thomas, G E; Graps, A

PVO observations of the interplanetary Ly-alpha (IPL) background, obtained over an entire solar cycle (SC) from 1979 to 1985, are compiled and analyzed statistically, along with data from other instruments and earlier solar cycles. The results are presented in extensive tables and graphs and characterized in detail. Findings reported include SC variation of 1.8 for the longitudinally averaged IPL intensity (in agreement with the variation of the 27-d disk-averaged integrated solar Ly-alpha flux), yearly averaged ecliptic H-atom lifetime at 1 AU equal to 1.0 Ms at solar minimum and 1.5 Ms at solar maximum, interplanetary H density equal to 0.07 + or - 0.01/cu cm, and interplanetary H/He within the heliopause but far from the sun of 7 + or - 3. 74 references.

• Research Organization: California Institute of Technology, Pasadena; Colorado Univ., Boulder
• OSTI ID: 6119503
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 317; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY SPACE
LYMAN LINES
PIONEER SPACE PROBES
SOLAR ACTIVITY
SOLAR CYCLE
SOLAR FLUX
SOLAR WIND
SPACE
SPACE VEHICLES
SPECTRA
ULTRAVIOLET SPECTRA
VARIATIONS
VEHICLES