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A satellite orbit drift in binary near-Earth asteroids (66391) 1999 KW4 and (88710) 2001 SL9 -- Indication of the BYORP effect

P. ScheirichAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicPetr PravecAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicP. KušnirákAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicK. HornochAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicJay W. McMahonDepartment of Aerospace Engineering Sciences, The University of Colorado at BoulderDaniel J. ScheeresDepartment of Aerospace Engineering Sciences, The University of Colorado at BoulderD. ČapekAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicDonald P. PraySugarloaf Mountain Observatory, South Deerfield, MAH. KučákováAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicA. GaládModra Observatory, SlovakiaJ. VraštilAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicYu. N. KruglyNicholas MoskovitzLowell Observatory, Flagstaff, AZLouis AvnerLunar and Planetary Laboratory, University of Arizona, Tucson, AZB. A. SkiffLowell Observatory, Flagstaff, AZR. S. McMillanLunar and Planetary Laboratory, University of Arizona, Tucson, AZJeffrey A. LarsenLunar and Planetary Laboratory, University of Arizona, Tucson, AZMelissa J. BruckerLunar and Planetary Laboratory, University of Arizona, Tucson, AZA. F. TubbioloLunar and Planetary Laboratory, University of Arizona, Tucson, AZWalt CooneyJ. GrossD. TerrellSonoita Research Observatory, Sonoita, AZО. БурхоновUlugh Beg Astronomical Institute, Tashkent, UzbekistanK. E. ErgashevUlugh Beg Astronomical Institute, Tashkent, UzbekistanSh. A. EhgamberdievUlugh Beg Astronomical Institute, Tashkent, UzbekistanPetr FatkaAstronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech RepublicRussell I. DurkeeEva Lilly SchunovaPlanetary Science Institute, Tucson, AZR. InasaridzeKharadze Abastumani Astrophysical Observatory, Tbilisi, GeorgiaV. AyvazianKharadze Abastumani Astrophysical Observatory, Tbilisi, GeorgiaG. V. KapanadzeKharadze Abastumani Astrophysical Observatory, Tbilisi, GeorgiaN. M. GaftonyukCrimean Astrophysical Observatory of Russian Academy of Sciences, Nauchny, UkraineJuan A. SanchezPlanetary Science Institute, Tucson, AZV. ReddyLunar and Planetary Laboratory, University of Arizona, Tucson, AZL. McGrawNorthern Arizona University, Flagstaff, AZMichael S. P. KelleyI. MolotovKeldysh Institute of Applied Mathematics, RAS, Moscow, Russia

arXiv (Cornell University)repository2019en

ABI

Annotatsiya

We obtained thorough photometric observations of two binary near-Earth asteroids (66391) Moshup = 1999 KW4 and (88710) 2001 SL9 taken from 2000 to 2019 and derived physical and dynamical properties of the binary systems. We found that the data for 1999 KW4 are inconsistent with a constant orbital period and we obtained unique solution with a quadratic drift of the mean anomaly of the satellite of -0.65 +/- 0.16 deg/yr2 (all quoted uncertainties are 3sigma). This means that the semimajor axis of the mutual orbit of the components of this binary system increases in time with a mean rate of 1.2 +/- 0.3 cm/yr. The data for 2001 SL9 are also inconsistent with a constant orbital period and we obtained two solutions for the quadratic drift of the mean anomaly: 2.8 +/- 0.2 and 5.2 +/- 0.2 deg/yr2, implying that the semimajor axis of the mutual orbit of the components decreases in time with a mean rate of -2.8 +/- 0.2 or -5.1 +/- 0.2 cm/yr for the two solutions, respectively. The expanding orbit of 1999 KW4 may be explained by mutual tides interplaying with binary YORP (BYORP) effect (McMahon and Scheeres, 2010). However, a modeling of the BYORP drift using radar-derived shapes of the binary components predicted a much higher value of the orbital drift than the observed one. It suggests that either the radar-derived shape model of the secondary is inadequate for computing the BYORP effect, or the present theory of BYORP overestimates it. It is possible that the BYORP coefficient has instead an opposite sign than predicted; in that case, the system may be moving into an equilibrium between the BYORP and the tides. In the case of 2001 SL9, the BYORP effect is the only known physical mechanism that can cause the inward drift of its mutual orbit.

Mavzular

Astro and Planetary Science Planetary Science and Exploration Geology and Paleoclimatology Research

Identifikatorlar

DOI: 10.48550/arxiv.1912.06456

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