Optical observations of NEA 162173 (1999 JU3) during the 2011-2012 apparition

Abstract

Near-Earth asteroid 162173 (1999 JU3) is a potential target of two asteroid sample return missions, not only because of its accessibility but also because of the first C-type asteroid for exploration missions. The lightcurve-related physical properties of this object were investigated during the 2011-2012 apparition. We aim to confirm the physical parameters useful for JAXA's Hayabusa 2 mission, such as rotational period, absolute magnitude, and phase function. Our data complement previous studies that did not cover low phase angles. With optical imagers and 1-2 m class telescopes, we acquired the photometric data at different phase angles. We independently derived the rotational lightcurve and the phase curve of the asteroid. We have analyzed the lightcurve of 162173 (1999 JU3), and derived a synodic rotational period of 7.625 +/- 0.003 h, the axis ratio a/b = 1.12. The absolute magnitude H_R = 18.69 +/- 0.07 mag and the phase slope of G = -0.09 +/- 0.03 were also obtained based on the observations made during the 2011-2012 apparition.

4 pages, 3 figures

References in corpus (1)

• A Fast Chi-squared Technique For Period Search of Irregularly Sampled Data

Cited by in corpus (4)

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• Physical properties of near-Earth asteroids with a low delta-$v$: Survey of target candidates for the Hayabusa2 mission
• Shape and Rotational Motion Models for Tumbling and Monolithic Asteroid 2012 $\mathrm{T}{\mathrm{C}}_4$:High Time Resolution Lightcurve with the Tomo-e Gozen Camera