TY - JOUR
T1 - Multi-wavelength observations of Asteroid 2100 Ra-Shalom
AU - Shepard, Michael K.
AU - Clark, Beth Ellen
AU - Nolan, Michael C.
AU - Benner, Lance A.M.
AU - Ostro, Steven J.
AU - Giorgini, Jon D.
AU - Vilas, Faith
AU - Jarvis, Kandy
AU - Lederer, Susan
AU - Lim, Lucy F.
AU - McConnochie, Tim
AU - Bell, James
AU - Margot, Jean Luc
AU - Rivkin, Andrew
AU - Magri, Christopher
AU - Scheeres, Daniel
AU - Pravec, Petr
N1 - Funding Information:
M.K.S. and B.E.C. gratefully acknowledge support from NSF grant AST-0307092. S.L. and F.V. are visiting astronomers at McDonald Observatory of the University of Texas, and this paper includes data taken there. M.K.S. and B.E.C. are visiting astronomers, Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement No. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation. We thank the technical staff at each observatory for help with observations. Some of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This material is based in part upon work supported by the National Aeronautics and Space Administration (NASA) under the Science Mission Directorate Research and Analysis Programs. C.M. was partially supported by NSF grant AST-0205975. D.J.S. acknowledges support from a grant from the Planetary Geology and Geophysics program in NASA's Office of Space Science.
PY - 2008/1
Y1 - 2008/1
N2 - We observed near-Earth asteroid (NEA) 2100 Ra-Shalom over a six-year period, obtaining rotationally resolved spectra in the visible, near-infrared, thermal-infrared, and radar wavelengths. We find that Ra-Shalom has an effective diameter of Deff = 2.3 ± 0.2 km, rotation period P = 19.793 ± 0.001 h, visual albedo pv = 0.13 ± 0.03, radar albedo over(σ, ̂)OC = 0.36 ± 0.10, and polarization ratio μc = 0.25 ± 0.04. We used our radar observations to generate a three-dimensional shape model which shows several structural features of interest. Based on our thermal observations, Ra-Shalom has a high thermal inertia of ∼103 J m-2 s-0.5 K-1, consistent with a coarse or rocky surface and the inferences of others [Harris, A.W., Davies, J.K., Green, S.F., 1998. Icarus 135, 441-450; Delbo, M., Harris, A.W., Binzel, R.P., Pravec, P., Davies, J.K., 2003. Icarus 166, 116-130]. Our spectral data indicate that Ra-Shalom is a K-class asteroid and we find excellent agreement between our spectra and laboratory spectra of the CV3 meteorite Grosnaja. Our spectra show rotation-dependent variations consistent with global variations in grain size. Our radar observations show rotation-dependent variations in radar albedo consistent with global variations in the thickness of a relatively thin regolith.
AB - We observed near-Earth asteroid (NEA) 2100 Ra-Shalom over a six-year period, obtaining rotationally resolved spectra in the visible, near-infrared, thermal-infrared, and radar wavelengths. We find that Ra-Shalom has an effective diameter of Deff = 2.3 ± 0.2 km, rotation period P = 19.793 ± 0.001 h, visual albedo pv = 0.13 ± 0.03, radar albedo over(σ, ̂)OC = 0.36 ± 0.10, and polarization ratio μc = 0.25 ± 0.04. We used our radar observations to generate a three-dimensional shape model which shows several structural features of interest. Based on our thermal observations, Ra-Shalom has a high thermal inertia of ∼103 J m-2 s-0.5 K-1, consistent with a coarse or rocky surface and the inferences of others [Harris, A.W., Davies, J.K., Green, S.F., 1998. Icarus 135, 441-450; Delbo, M., Harris, A.W., Binzel, R.P., Pravec, P., Davies, J.K., 2003. Icarus 166, 116-130]. Our spectral data indicate that Ra-Shalom is a K-class asteroid and we find excellent agreement between our spectra and laboratory spectra of the CV3 meteorite Grosnaja. Our spectra show rotation-dependent variations consistent with global variations in grain size. Our radar observations show rotation-dependent variations in radar albedo consistent with global variations in the thickness of a relatively thin regolith.
KW - Asteroids
KW - Radar observations
KW - composition
KW - surfaces
UR - https://www.scopus.com/pages/publications/36849036887
UR - https://www.scopus.com/pages/publications/36849036887#tab=citedBy
U2 - 10.1016/j.icarus.2007.09.006
DO - 10.1016/j.icarus.2007.09.006
M3 - Article
AN - SCOPUS:36849036887
SN - 0019-1035
VL - 193
SP - 20
EP - 38
JO - Icarus
JF - Icarus
IS - 1
ER -