Radar observations and a physical model of Asteroid 4660 Nereus, a prime space mission target

Marina Brozovic; Steven J. Ostro; Lance A.M. Benner; Jon D. Giorgini; Raymond F. Jurgens; Randy Rose; Michael C. Nolan; Alice A. Hine; Christopher Magri; Daniel J. Scheeres; Jean Luc Margot

doi:10.1016/j.icarus.2008.12.029

Radar observations and a physical model of Asteroid 4660 Nereus, a prime space mission target

Marina Brozovic, Steven J. Ostro, Lance A.M. Benner, Jon D. Giorgini, Raymond F. Jurgens, Randy Rose, Michael C. Nolan, Alice A. Hine, Christopher Magri, Daniel J. Scheeres, Jean Luc Margot

Research output: Contribution to journal › Article › peer-review

27 Scopus citations

Abstract

Near-Earth Asteroid 4660 Nereus has been identified as a potential spacecraft target since its 1982 discovery because of the low delta-V required for a spacecraft rendezvous. However, surprisingly little is known about its physical characteristics. Here we report Arecibo (S-band, 2380-MHz, 13-cm) and Goldstone (X-band, 8560-MHz, 3.5-cm) radar observations of Nereus during its 2002 close approach. Analysis of an extensive dataset of delay-Doppler images and continuous wave (CW) spectra yields a model that resembles an ellipsoid with principal axis dimensions X = 510 ± 20 m, Y = 330 ± 20 m and Z = 241_{- 10}^{+ 80} m. The pole direction is approximately located at ecliptic pole longitude and latitude of λ = + 25 °, β = + 80 ° with the uncertainty radius of 10°. Our modeling yields a refined rotation period of 15.16 ± 0.04 h. Nereus has a circular polarization (SC/OC) ratio of 0.74 ± 0.08, which implies substantial near-surface centimeter-to-decimeter scale roughness. Dynamical analysis of our model suggests that YORP alteration of the rotation period may become evident within a few years. Nereus has two stable synchronous orbits where natural material may remain in orbit, while most asteroids observed to date do not have such stable synchronous orbits. We also find that spacecraft orbits about Nereus are feasible.

Original language	English (US)
Pages (from-to)	153-166
Number of pages	14
Journal	Icarus
Volume	201
Issue number	1
DOIs	https://doi.org/10.1016/j.icarus.2008.12.029
State	Published - May 2009
Externally published	Yes

Keywords

Asteroids
Radar observations

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1016/j.icarus.2008.12.029

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@article{32761abce2b9419fa9eadabdb36286ff,

title = "Radar observations and a physical model of Asteroid 4660 Nereus, a prime space mission target",

abstract = "Near-Earth Asteroid 4660 Nereus has been identified as a potential spacecraft target since its 1982 discovery because of the low delta-V required for a spacecraft rendezvous. However, surprisingly little is known about its physical characteristics. Here we report Arecibo (S-band, 2380-MHz, 13-cm) and Goldstone (X-band, 8560-MHz, 3.5-cm) radar observations of Nereus during its 2002 close approach. Analysis of an extensive dataset of delay-Doppler images and continuous wave (CW) spectra yields a model that resembles an ellipsoid with principal axis dimensions X = 510 ± 20 m, Y = 330 ± 20 m and Z = 241- 10+ 80 m. The pole direction is approximately located at ecliptic pole longitude and latitude of λ = + 25 °, β = + 80 ° with the uncertainty radius of 10°. Our modeling yields a refined rotation period of 15.16 ± 0.04 h. Nereus has a circular polarization (SC/OC) ratio of 0.74 ± 0.08, which implies substantial near-surface centimeter-to-decimeter scale roughness. Dynamical analysis of our model suggests that YORP alteration of the rotation period may become evident within a few years. Nereus has two stable synchronous orbits where natural material may remain in orbit, while most asteroids observed to date do not have such stable synchronous orbits. We also find that spacecraft orbits about Nereus are feasible.",

keywords = "Asteroids, Radar observations",

author = "Marina Brozovic and Ostro, {Steven J.} and Benner, {Lance A.M.} and Giorgini, {Jon D.} and Jurgens, {Raymond F.} and Randy Rose and Nolan, {Michael C.} and Hine, {Alice A.} and Christopher Magri and Scheeres, {Daniel J.} and Margot, {Jean Luc}",

note = "Funding Information: We thank the Arecibo and Goldstone technical and support staffs for help with the radar observations. 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 (NSF) and, at the time of this experiment, also had support from the National Aeronautics and Space Administration (NASA). We are very much in debt to the reviewers, Bob Gaskell and an anonymous reviewer whose comments significantly improved this paper. We would also like to thank Michael W. Busch for useful discussion on SHAPE modeling. Some of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This material is based in part upon work supported by NASA under the Science Mission Directorate Research and Analysis Programs. ",

year = "2009",

month = may,

doi = "10.1016/j.icarus.2008.12.029",

language = "English (US)",

volume = "201",

pages = "153--166",

journal = "Icarus",

issn = "0019-1035",

publisher = "Academic Press Inc.",

number = "1",

}

TY - JOUR

T1 - Radar observations and a physical model of Asteroid 4660 Nereus, a prime space mission target

AU - Brozovic, Marina

AU - Ostro, Steven J.

AU - Benner, Lance A.M.

AU - Giorgini, Jon D.

AU - Jurgens, Raymond F.

AU - Rose, Randy

AU - Nolan, Michael C.

AU - Hine, Alice A.

AU - Magri, Christopher

AU - Scheeres, Daniel J.

AU - Margot, Jean Luc

N1 - Funding Information: We thank the Arecibo and Goldstone technical and support staffs for help with the radar observations. 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 (NSF) and, at the time of this experiment, also had support from the National Aeronautics and Space Administration (NASA). We are very much in debt to the reviewers, Bob Gaskell and an anonymous reviewer whose comments significantly improved this paper. We would also like to thank Michael W. Busch for useful discussion on SHAPE modeling. Some of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This material is based in part upon work supported by NASA under the Science Mission Directorate Research and Analysis Programs.

PY - 2009/5

Y1 - 2009/5

N2 - Near-Earth Asteroid 4660 Nereus has been identified as a potential spacecraft target since its 1982 discovery because of the low delta-V required for a spacecraft rendezvous. However, surprisingly little is known about its physical characteristics. Here we report Arecibo (S-band, 2380-MHz, 13-cm) and Goldstone (X-band, 8560-MHz, 3.5-cm) radar observations of Nereus during its 2002 close approach. Analysis of an extensive dataset of delay-Doppler images and continuous wave (CW) spectra yields a model that resembles an ellipsoid with principal axis dimensions X = 510 ± 20 m, Y = 330 ± 20 m and Z = 241- 10+ 80 m. The pole direction is approximately located at ecliptic pole longitude and latitude of λ = + 25 °, β = + 80 ° with the uncertainty radius of 10°. Our modeling yields a refined rotation period of 15.16 ± 0.04 h. Nereus has a circular polarization (SC/OC) ratio of 0.74 ± 0.08, which implies substantial near-surface centimeter-to-decimeter scale roughness. Dynamical analysis of our model suggests that YORP alteration of the rotation period may become evident within a few years. Nereus has two stable synchronous orbits where natural material may remain in orbit, while most asteroids observed to date do not have such stable synchronous orbits. We also find that spacecraft orbits about Nereus are feasible.

AB - Near-Earth Asteroid 4660 Nereus has been identified as a potential spacecraft target since its 1982 discovery because of the low delta-V required for a spacecraft rendezvous. However, surprisingly little is known about its physical characteristics. Here we report Arecibo (S-band, 2380-MHz, 13-cm) and Goldstone (X-band, 8560-MHz, 3.5-cm) radar observations of Nereus during its 2002 close approach. Analysis of an extensive dataset of delay-Doppler images and continuous wave (CW) spectra yields a model that resembles an ellipsoid with principal axis dimensions X = 510 ± 20 m, Y = 330 ± 20 m and Z = 241- 10+ 80 m. The pole direction is approximately located at ecliptic pole longitude and latitude of λ = + 25 °, β = + 80 ° with the uncertainty radius of 10°. Our modeling yields a refined rotation period of 15.16 ± 0.04 h. Nereus has a circular polarization (SC/OC) ratio of 0.74 ± 0.08, which implies substantial near-surface centimeter-to-decimeter scale roughness. Dynamical analysis of our model suggests that YORP alteration of the rotation period may become evident within a few years. Nereus has two stable synchronous orbits where natural material may remain in orbit, while most asteroids observed to date do not have such stable synchronous orbits. We also find that spacecraft orbits about Nereus are feasible.

KW - Asteroids

KW - Radar observations

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DO - 10.1016/j.icarus.2008.12.029

M3 - Article

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SP - 153

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JO - Icarus

JF - Icarus

IS - 1

ER -

Radar observations and a physical model of Asteroid 4660 Nereus, a prime space mission target

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