Asteroid (3200) Phaethon: results of polarimetric, photometric, and spectral observations
Abstract
We present results of polarimetric, photometric, and spectral observations of the nearEarth asteroid (3200) Phaethon carried out at the 6m BTA telescope of the Special Astrophysical Observatory and the 2.6m and 1.25m telescopes of the Crimean Astrophysical Observatory over a wide range of phase angles during its close approach to the Earth at the end of 2017 (α = 19°135°) and in 2020 at α = 52.2°. Using our and other available in literature data, we found that the maximum degree of linear polarization of Phaethon in the V band is P_{max} = (45 ± 1) per cent at the phase angle α_{max} = 124.0° ± 0.4°, whereas the inversion angle α_{inv} = 21.4° ± 1.2° and polarimetric slope is h = (0.326 ± 0.027) per cent per degree. Using the dependence 'polarimetric slope  albedo,' we have found the geometric albedo of asteroid Phaethon to be p_{v} = 0.060 ± 0.005. This value falls into the lower range of albedo values for asteroids determined by different methods. The mean colour indices UB = 0.207 ^{m} ± 0.053 ^{m} and BV = 0.639 ^{m} ± 0.054 ^{m} of the asteroid are derived at heliocentric and geocentric distances 1.077 au and 0.102 au, respectively, and phase angle α = 23.78°. The absolute magnitude of Phaethon is V(1,1,0) = 14.505 ^{m} ± 0.059 ^{m}. The effective diameter of Phaethon is estimated from obtained absolute magnitude and geometrical albedo, it is equal to 6.8 ± 0.3 km. The best fit to the observed polarimetric data was obtained with the Shmatrix model of conjugated random Gaussian particles composed of Mgrich silicate (90 per cent) and amorphous carbon (10 per cent).
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 August 2022
 DOI:
 10.1093/mnras/stac1559
 arXiv:
 arXiv:2206.00911
 Bibcode:
 2022MNRAS.514.4861K
 Keywords:

 minor planets;
 asteroids: individual: (3200) Phaethon;
 methods: data analysis;
 methods: observational;
 methods: numerical;
 techniques: photometry;
 techniques: polarimetry;
 techniques: spectroscopy;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 27 pages, 9 figures