Abstract/Details

Effects of airbursts on the surface of Venus


2000 2000

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Abstract (summary)

Magellan observed quasi-circular, apparently impact-related, radar albedo features on Venus. Pristine examples show dark regions centered within larger bright regions. Dark regions are interpreted as smooth and bright regions are interpreted as rough. Of the 518 features, 256 are centered on impact craters (crater haloes), 53 are centered upon small central disturbances (disrupted splotches), and the remaining 209 exhibit no central structure (craterless splotches). Most researchers interpret these features as airburst scars.

Previous models of airburst formation only reproduced subsets of the observations. Models of splotch and halo formation were often mutually exclusive and no previous model connected them despite their similarities. I rectify this problem with a model that successfully reproduces 514 of the 518 patterns given appropriate airburst altitude and energy conditions combined with erosion. In my model, dark zones are pulverized rock, and bright zones are scoured surfaces. More complicated patterns are obtained with modification of the initial dark/bright pattern.

Small impactors that do not penetrate the atmosphere cannot cause surface damage. Large impactors that penetrate the atmosphere without disruption create an impact crater without an associated airburst scar. Only intermediate-size impactors, partially or wholly disrupted in the near-surface zone, form airburst scars. Typical diameters for airburst scar-forming impactors are 200 meters—2 km for irons, 300 meters—3 km for stones, and >3 km for comets.

Indexing (details)


Subject
Astronomy;
Astrophysics;
Geophysics
Classification
0606: Astronomy
0606: Astrophysics
0373: Geophysics
Identifier / keyword
Pure sciences; Earth sciences; Airbursts; Crater halo; Radar albedo; Surface impacts; Venus
Title
Effects of airbursts on the surface of Venus
Author
Wood, David Allen, Jr.
Number of pages
263
Publication year
2000
Degree date
2000
School code
0009
Source
DAI-B 61/08, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780599902138, 0599902132
Advisor
Strom, Robert G.
University/institution
The University of Arizona
University location
United States -- Arizona
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
9983856
ProQuest document ID
304581239
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304581239
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