Spin Change of Asteroid 2012 TC4 Probably by Radiation Torques
Draft version December 17, 2020 Typeset using LATEX default style in AASTeX63 Spin Change of Asteroid 2012 TC4 probably by Radiation Torques Hee-Jae Lee,1, 2 Josef Durech,ˇ 3 David Vokrouhlicky,´ 3 Petr Pravec,4 Hong-Kyu Moon,2 William Ryan,5 Myung-Jin Kim,2 Chun-Hwey Kim,1 Young-Jun Choi,2, 6 Paolo Bacci,7 Joe Pollock,8 and Rolf Apitzsch9 1Chungbuk National University, 1 Chungdae-ro, Seowon-gu, Cheongju, Chungbuk 28644, Korea 2Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Korea 3Astronomical Institute, Faculty of Mathematics and Physics, Charles University, V Holeˇsoviˇck´ach2, 180 00 Prague 8, Czech Republic 4Astronomical Institute, Academy of Sciences of the Czech Republic, Friˇcova1, 251 65 Ondˇrejov,Czech Republic 5New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA 6University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea 7Gruppo Astrofili Montagna Pistoiese, 51028 San Marcello Piteglio, Province of Pistoia, Italia 8Physics and Astronomy Department, Appalachian State University, Boone, NC 28608, USA 9Wildberg Observatory, 72218 Wildberg, Germany (Received; Revised; Accepted) Submitted to AJ ABSTRACT Asteroid 2012 TC4 is a small (∼10 m) near-Earth object that was observed during its Earth close approaches in 2012 and 2017. Earlier analyses of light curves revealed its excited rotation state. We collected all available photometric data from the two apparitions to reconstruct its rotation state and convex shape model. We show that light curves from 2012 and 2017 cannot be fitted with a single set of model parameters { the rotation and precession periods are significantly different for these two data sets and they must have changed between or during the two apparitions.
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