Shape model and spin-state analysis of PHA contact binary (85990) 1999 JV6 from combined radar and optical observations
Author
Rożek, A.Lowry, S. C.
Nolan, M. C.
Taylor, P. A.
Benner, L. A. M.
Fitzsimmons, A.
Zegmott, T. J.
Weissman, P. R.
Green, S. F.
Rozitis, B.
Snodgrass, C.
Smythe, W. D.
Hicks, M. D.
Howell, E. S.
Virkki, A. K.
Aponte-Hernandez, B.
Rivera-Valentín, E. G.
Rodriguez-Ford, L. A.
Zambrano-Marin, L. F.
Brozović, M.
Naidu, S. P.
Giorgini, J. D.
Snedeker, L. G.
Jao, J. S.
Ghigo, F. D.
Affiliation
Univ Arizona, Lunar & Planetary LabIssue Date
2019-11-13Keywords
minor planetsasteroids: individual: (85990) 1999 JV6
methods: observational
methods: data analysis
techniques: photometric
techniques: radar astronomy
radiation mechanisms: thermal
Metadata
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EDP SCIENCES S ACitation
Rożek, A., Lowry, S. C., Nolan, M. C., Taylor, P. A., Benner, L. A. M., Fitzsimmons, A., … Ghigo, F. D. (2019). Shape model and spin-state analysis of PHA contact binary (85990) 1999 JV6 from combined radar and optical observations. Astronomy & Astrophysics, 631, A149. https://doi.org/10.1051/0004-6361/201936302 Journal
ASTRONOMY & ASTROPHYSICSRights
Copyright © ESO 2019.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Context. The potentially hazardous asteroid (85990) 1999 JV6 has been a target of previously published thermal-infrared observations and optical photometry. It has been identified as a promising candidate for possible Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect detection. Aims. The YORP effect is a small thermal-radiation torque considered to be a key factor in spin-state evolution of small Solar System bodies. In order to detect YORP on 1999 JV6 we developed a detailed shape model and analysed the spin-state using both optical and radar observations. Methods. For 1999 JV6, we collected optical photometry between 2007 and 2016. Additionally, we obtained radar echo-power spectra and imaging observations with Arecibo and Goldstone planetary radar facilities in 2015, 2016, and 2017. We combined our data with published optical photometry to develop a robust physical model. Results. We determine that the rotation pole resides at negative latitudes in an area with a 5 degrees radius close to the south ecliptic pole. The refined sidereal rotation period is 6.536787 +/- 0.000007 h. The radar images are best reproduced with a bilobed shape model. Both lobes of 1999 JV6 can be represented as oblate ellipsoids with a smaller, more spherical component resting at the end of a larger, more elongated component. While contact binaries appear to be abundant in the near-Earth population, there are only a few published shape models for asteroids in this particular configuration. By combining the radar-derived shape model with optical light curves we determine a constant-period solution that fits all available data well. Using light-curve data alone we determine an upper limit for YORP of 8.5 x 10(-8) rad day(-2). Conclusions. The bifurcated shape of 1999 JV6 might be a result of two ellipsoidal components gently merging with each other, or a deformation of a rubble pile with a weak-tensile-strength core due to spin-up. The physical model of 1999 JV6 presented here will enable future studies of contact binary asteroid formation and evolution.ISSN
0004-6361Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1051/0004-6361/201936302