@article{495eb59b22e54ee6894484dab3fb0506,
title = "The mean rotation rate of Venus from 29 years of Earth-based radar observations",
abstract = "We measured the length of the Venus sidereal day (LOD) from Earth-based radar observations collected from 1988 to 2017, using offsets in surface feature longitudes from a prediction based on a 243.0185d period derived from analysis of Magellan mission images over a 487-day interval. We derive a mean LOD over 29 years of 243.0212 ± 0.0006d. Our result is consistent with earlier estimates (but with smaller uncertainties), including those based on offsets between Venus Express infrared mapping data and Magellan topography that suggest a mean LOD of 243.0228 ± 0.002d over a 16-year interval. We cannot detect subtle, short-term oscillations in rate, but the derived value provides an excellent fit to observational data over a 29-year period that can be used for future landing-site planning.",
keywords = "Radar observations, Rotational dynamics, Venus",
author = "Campbell, {Bruce A.} and Campbell, {Donald B.} and Carter, {Lynn M.} and Chandler, {John F.} and Giorgini, {J. D.} and Margot, {Jean Luc} and Morgan, {Gareth A.} and Nolan, {Michael C.} and Perillat, {Phillip J.} and Whitten, {Jennifer L.}",
note = "Funding Information: The authors thank R. Lorenz and A. Stark for their constructive reviews. Staff at the Arecibo Observatory and Green Bank Observatory provided invaluable assistance in collecting the Earth-based data. Arecibo Observatory is a NSF facility operated under cooperative agreement by University of Central Florida (UCF), Yang Enterprises (YEI) and Universidad Metropolitana (UMET). The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work was funded in part by a grant to B.A.C. from NASA 's Planetary Observations Program ( NNX-15AD96G ). Some research was also carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The delay-Doppler images for observation years 1988, 2012, 2015, and 2017 are available through the NASA Planetary Data System Geoscience Node ( http://pds-geosciences.wustl.edu/missions/venus_radar/index.htm ). Funding Information: The authors thank R. Lorenz and A. Stark for their constructive reviews. Staff at the Arecibo Observatory and Green Bank Observatory provided invaluable assistance in collecting the Earth-based data. Arecibo Observatory is a NSF facility operated under cooperative agreement by University of Central Florida (UCF), Yang Enterprises (YEI) and Universidad Metropolitana (UMET). The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work was funded in part by a grant to B.A.C. from NASA's Planetary Observations Program (NNX-15AD96G). Some research was also carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The delay-Doppler images for observation years 1988, 2012, 2015, and 2017 are available through the NASA Planetary Data System Geoscience Node (http://pds-geosciences.wustl.edu/missions/venus_radar/index.htm). Publisher Copyright: {\textcopyright} 2019 Elsevier Inc.",
year = "2019",
month = nov,
day = "1",
doi = "10.1016/j.icarus.2019.06.019",
language = "English (US)",
volume = "332",
pages = "19--23",
journal = "Icarus",
issn = "0019-1035",
publisher = "Academic Press Inc.",
}