paper

Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit

arXiv:2006.08304 · doi:10.1093/mnras/staa1728

Abstract

The first known asteroid with the orbit inside that of Venus is 2020~AV $_{2}$ . 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~AV $_{2}$ 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~AV $_{2}$ in the 0.5-1.5~ $I^¼ m$ wavelength interval. These were performed with the Nordic Optical Telescope and the William Herschel Telescope. Based on the obtained spectra, we classify 2020~AV $_{2}$ as a Sa-type asteroid. We estimate the diameter of this Vatira to be $1.5 0_{- 0.65}^{+ 1.10}$ km by considering the average albedo of A-type and S-complex asteroids ( $p_{V} = 0.2 3_{- 0.08}^{+ 0.11}$ ), and the absolute magnitude (H= $16.40 \pm 0.78$ mag). The wide spectral band around 1~ $I^¼ m$ shows the signature of an olivine rich composition. The estimated band centre $B I C = 1.08 \pm 0.02 I^¼ m$ corresponds to a ferroan olivine mineralogy similar to that of brachinite meteorites.

Accepted for publication in MNRAS. 10 pages, 5 figures,