2020MNRAS.496.3572P

The first known asteroid with the orbit inside that of Venus is 2020 AV₂. This may be the largest member of a new population of small bodies with the aphelion smaller than 0.718 au, called Vatiras. The surface of 2020 AV₂ is being constantly modified by the high temperature, by the strong solar wind irradiation that characterizes the innermost region of the Solar system, and by high-energy micrometeorite impacts. The study of its physical properties represents an extreme test-case for the science of near-Earth asteroids. Here, we report spectroscopic observations of 2020 AV₂ in the 0.5-1.5-µm wavelength interval. These were performed with the Nordic Optical Telescope and the William Herschel Telescope. Based on the obtained spectra, we classify 2020 AV₂ as a Sa-type asteroid. We estimate the diameter of this Vatira to be 1.50_–0.65^+1.10 km by considering the average albedo of A-type and S-complex asteroids (p_V=0.23_–0.08^+0.11), and the absolute magnitude (H = 16.40 ± 0.78 mag). The wide spectral band around 1 µm shows the signature of an olivine-rich composition. The estimated band centre BIC = 1.08 ± 0.02 µm corresponds to a ferroan olivine mineralogy similar to that of brachinite meteorites.