Optical observations of the potentially hazardous asteroid (4660) Nereus at opposition 2021
Troianskyi V. Godunova V. Serebryanskiy A. Aimanova G. Franco L. Marchini A. Bacci P. Maestripieri M. Berezin D. Ivanova O. Maigurova N. Panko E. Taradii V. Khlamov S.
15 September 2024Academic Press Inc.
Icarus
2024#420
On 11 December 2021 at 11 UTC, the near-Earth asteroid (4660) Nereus passed the Earth at a distance of 0.0263 au, reaching about 13th magnitude that made it an excellent target for ground-based observations. We observed the asteroid photometrically from 11 October 2021, when it was visible at V = 17.7 mag, until 16 February 2022 (at V = 18.0 mag), and spectroscopically on 10 December 2021 (V ∼ 13.1 mag). Lightcurve analysis of (4660) Nereus gave a rotational period of 15.184245±0.000015 h with amplitude of 0.796 ± 0.052 mag. Fitting the magnitude-phase curve with the standard HG, HG1G2, HG12 functions yielded the following values: HR = 18.68−0.13+0.07 mag, G = 0.30−0.11+0.05; HR = 18.64−0.84+0.42 mag, G1 = 0.21−0.11+0.05, G2 = 0.46−0.23+0.22; HR = 18.61−0.07+0.13 mag, G12 = 0.18−0.18+0.18. The color indices of the asteroid at phase angle of 72.9° were found to be as follows: (B−V) = 0.688 ± 0.084, (B−R) = 1.046 ± 0.073, (V−R) = 0.358 ± 0.047, (V−I) = 0.718 ± 0.050. Its equivalent diameter was estimated as 0.34−0.10+0.07 km. These values, as well as the computed values of G1 and G2 coefficients, indicate that (4660) Nereus belongs to E-class asteroids. The same conclusion was made based on the spectra obtained.
Asteroid (4660) Nereus , Photometry , Spectroscopy
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Department of Physics and Astronomy FMPIT of Odesa I. I. Mechnikov National University, Pastera Street 42, Odesa, 65082, Ukraine
Department of Physics and Methods of Teaching, Faculty of Physics and Technology, Vasyl Stefanyk Precarpathian National University, Shevchenko Street 57, Ivano-Frankivsk, 76000, Ukraine
ICAMER Observatory of NASU, 27 Acad. Zabolotnoho str., Kyiv, 03143, Ukraine
Fesenkov Astrophysical Institute, Observatory 23, Almaty, 050020, Kazakhstan
Balzaretto Observatory, Rome, Italy
University of Siena, Astronomical Observatory, Via Roma 56, Siena, 53100, Italy
GAMP - San Marcello Pistoiese, Pistoia, Italy
Astronomical Institute of the Slovak Academy of Sciences, Tatranská Lomnica, SK-05960, Slovakia
Main Astronomical Observatory of National Academy of Sciences, 27 Acad. Zabolotnoho str., Kyiv, 03143, Ukraine
Research Institute “Mykolaiv Astronomical Observatory”, Mykolaiv, 54030, Ukraine
Shanghai Astronomical Observatory, Chinese Academy of Science, Shanghai, 200030, China
Department of Media Systems and Technologies of Kharkiv National University of Radio Electronics, Nauki ave., 14, Kharkiv, 61166, Ukraine
Department of Physics and Astronomy FMPIT of Odesa I. I. Mechnikov National University
Department of Physics and Methods of Teaching
ICAMER Observatory of NASU
Fesenkov Astrophysical Institute
Balzaretto Observatory
University of Siena
GAMP - San Marcello Pistoiese
Astronomical Institute of the Slovak Academy of Sciences
Main Astronomical Observatory of National Academy of Sciences
Research Institute “Mykolaiv Astronomical Observatory”
Shanghai Astronomical Observatory
Department of Media Systems and Technologies of Kharkiv National University of Radio Electronics
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