Observations of the Optically Thin Scattering Layer in the Atmosphere of Venus.

Abstract

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of the Optically Thin Scattering Layer in the Atmosphere of Venus. Smith, Bradford A. ; Bains, Walter E. Abstract The existence of an optically thin scattering layer overlying an opaque surface on Venus was established through observations of cusp extensions near inferior conjunction by visual observers during the 18th and 19th centuries. H. N. Russell (Astrophys. J. 9, 284,1899) was probably the first to publish a correct analysis of these observations. He concluded that a relatively bright haze layer extends upward somewhat more thai~ 1 km above the top of the opaque cioud cover, ai~d that a much weaker layer reaches a height of 10 km. A photographic study of the cusp extensions was first undertaken by J. B. Edson (Proc. Lunar Planetary Explor. Coil. No. 5, 22, 1959) and his co-workers in 1938 and 1940. Edson not only gave photographic confirmation to the earlier visual observations, but also established that the extension angles of the two cusps are usually asymmetric. More recently, photographic observations have been made at the New Mexico State University during the inferior conjunctions of 1959,1961, and 1962. In addition to confirming Fdson's observations, the New Mexico photographs indicate the probable existence of very weak scattering at heights as great as 30-40 km above the opaque surface. The analysis of these observations, however, is unfortunately complicated by the possibility that the level of the effective opaque sur%ce on Venus may not be identical ui~der all terrestrial observing conditions. A composite of the heights published by Fdson ai~d those obtained by the writers (at elongation angles less than 10 degrees) suggests a symmetr~ about an axis nearly perpendicular to the orbital plai~e. Symmetry about any axis other than the orbital radius vector can be produced oi~ly by rotation. Our observations, thei~, tend to conflict with the current coi~cept of synchronous rotatioi~ of Venus. This work was supported by the National Aeroi~autics and Space Administratioi~. Publication: The Astronomical Journal Pub Date: 1964 DOI: 10.1086/109379 Bibcode: 1964AJ.....69Q.150S full text sources ADS |