Radar observations and shape model of asteroid 16 Psyche
Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) imag...
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ftcaltechauth:oai:authors.library.caltech.edu:94929 2023-05-15T18:23:01+02:00 Radar observations and shape model of asteroid 16 Psyche Shepard, Michael K. Richardson, James Taylor, Patrick A. Rodriguez-Ford, Linda A. Conrad, Al de Pater, Imke Ádamkovics, Mate de Kleer, Katherine Males, Jared R. Morzinski, Katie M. Close, Laird M. Kaasalainen, Mikko Viikinkoski, Matti Timerson, Bradley Reddy, Vishnu Magri, Christopher Nolan, Michael C. Howell, Ellen S. Benner, Lance A. M. Giorgini, Jon D. Warner, Brian D. Harris, Alan W. 2017-01-01 https://authors.library.caltech.edu/94929/ https://resolver.caltech.edu/CaltechAUTHORS:20190424-103201183 unknown Elsevier Shepard, Michael K. and Richardson, James and Taylor, Patrick A. and Rodriguez-Ford, Linda A. and Conrad, Al and de Pater, Imke and Ádamkovics, Mate and de Kleer, Katherine and Males, Jared R. and Morzinski, Katie M. and Close, Laird M. and Kaasalainen, Mikko and Viikinkoski, Matti and Timerson, Bradley and Reddy, Vishnu and Magri, Christopher and Nolan, Michael C. and Howell, Ellen S. and Benner, Lance A. M. and Giorgini, Jon D. and Warner, Brian D. and Harris, Alan W. (2017) Radar observations and shape model of asteroid 16 Psyche. Icarus, 281 . pp. 388-403. ISSN 0019-1035. doi:10.1016/j.icarus.2016.08.011. https://resolver.caltech.edu/CaltechAUTHORS:20190424-103201183 <https://resolver.caltech.edu/CaltechAUTHORS:20190424-103201183> Article PeerReviewed 2017 ftcaltechauth https://doi.org/10.1016/j.icarus.2016.08.011 2021-11-18T18:50:29Z Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images (Drummond et al., 2016) to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image (Hanus et al., 2013) and three multi-chord occultations. Our shape model has dimensions 279 × 232 × 189 km (± 10%), D_(eff) = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves (Hanus et al., 2013). Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ∼50–70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kgm^(−3). Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ∼40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features. Article in Journal/Newspaper South pole Caltech Authors (California Institute of Technology) South Pole Icarus 281 388 403 |
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Caltech Authors (California Institute of Technology) |
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description |
Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images (Drummond et al., 2016) to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image (Hanus et al., 2013) and three multi-chord occultations. Our shape model has dimensions 279 × 232 × 189 km (± 10%), D_(eff) = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves (Hanus et al., 2013). Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ∼50–70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kgm^(−3). Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ∼40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features. |
format |
Article in Journal/Newspaper |
author |
Shepard, Michael K. Richardson, James Taylor, Patrick A. Rodriguez-Ford, Linda A. Conrad, Al de Pater, Imke Ádamkovics, Mate de Kleer, Katherine Males, Jared R. Morzinski, Katie M. Close, Laird M. Kaasalainen, Mikko Viikinkoski, Matti Timerson, Bradley Reddy, Vishnu Magri, Christopher Nolan, Michael C. Howell, Ellen S. Benner, Lance A. M. Giorgini, Jon D. Warner, Brian D. Harris, Alan W. |
spellingShingle |
Shepard, Michael K. Richardson, James Taylor, Patrick A. Rodriguez-Ford, Linda A. Conrad, Al de Pater, Imke Ádamkovics, Mate de Kleer, Katherine Males, Jared R. Morzinski, Katie M. Close, Laird M. Kaasalainen, Mikko Viikinkoski, Matti Timerson, Bradley Reddy, Vishnu Magri, Christopher Nolan, Michael C. Howell, Ellen S. Benner, Lance A. M. Giorgini, Jon D. Warner, Brian D. Harris, Alan W. Radar observations and shape model of asteroid 16 Psyche |
author_facet |
Shepard, Michael K. Richardson, James Taylor, Patrick A. Rodriguez-Ford, Linda A. Conrad, Al de Pater, Imke Ádamkovics, Mate de Kleer, Katherine Males, Jared R. Morzinski, Katie M. Close, Laird M. Kaasalainen, Mikko Viikinkoski, Matti Timerson, Bradley Reddy, Vishnu Magri, Christopher Nolan, Michael C. Howell, Ellen S. Benner, Lance A. M. Giorgini, Jon D. Warner, Brian D. Harris, Alan W. |
author_sort |
Shepard, Michael K. |
title |
Radar observations and shape model of asteroid 16 Psyche |
title_short |
Radar observations and shape model of asteroid 16 Psyche |
title_full |
Radar observations and shape model of asteroid 16 Psyche |
title_fullStr |
Radar observations and shape model of asteroid 16 Psyche |
title_full_unstemmed |
Radar observations and shape model of asteroid 16 Psyche |
title_sort |
radar observations and shape model of asteroid 16 psyche |
publisher |
Elsevier |
publishDate |
2017 |
url |
https://authors.library.caltech.edu/94929/ https://resolver.caltech.edu/CaltechAUTHORS:20190424-103201183 |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_relation |
Shepard, Michael K. and Richardson, James and Taylor, Patrick A. and Rodriguez-Ford, Linda A. and Conrad, Al and de Pater, Imke and Ádamkovics, Mate and de Kleer, Katherine and Males, Jared R. and Morzinski, Katie M. and Close, Laird M. and Kaasalainen, Mikko and Viikinkoski, Matti and Timerson, Bradley and Reddy, Vishnu and Magri, Christopher and Nolan, Michael C. and Howell, Ellen S. and Benner, Lance A. M. and Giorgini, Jon D. and Warner, Brian D. and Harris, Alan W. (2017) Radar observations and shape model of asteroid 16 Psyche. Icarus, 281 . pp. 388-403. ISSN 0019-1035. doi:10.1016/j.icarus.2016.08.011. https://resolver.caltech.edu/CaltechAUTHORS:20190424-103201183 <https://resolver.caltech.edu/CaltechAUTHORS:20190424-103201183> |
op_doi |
https://doi.org/10.1016/j.icarus.2016.08.011 |
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Icarus |
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281 |
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403 |
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