Rotation state, colors, and albedo of the mission-accessible tiny near-Earth asteroid 2001 QJ$_{142}$

Abstract

Context. Characterizing mission-accessible asteroids using telescopic observations is fundamental for target-selection and planning for spacecraft missions. Near-Earth asteroids on Earth-like orbits are of particular importance for applications such as asteroid mining. Aims. 2001 QJ142 is a tiny (D $\leq$ 100 m) near-Earth asteroid on an Earth-like orbit with a semimajor axis of 1.06 au, orbital eccentricity of 0.09, and orbital inclination of 3.10$^{\circ}$. We aim to characterize 2001 QJ142 using ground-based observations with future spacecraft missions in mind. Methods. We performed visible multicolor photometry of 2001 QJ142 using the TriCCS on the Seimei 3.8 m telescope in February 2024. We also revisited the images taken with the Suprime-Cam on the Subaru 8.2 m telescope in August 2012. Results. Visible color indices of 2001 QJ142 indicate that 2001 QJ142 is a C- or X-complex asteroid. We detect a possible fast rotation with a period of about 10 min, which is consistent with a previous report. The geometric albedo of 2001 QJ142 is derived to be about 0.3 from a slope of its photometric phase curve, which is consistent with an albedo derived from thermal observations with updated physical quantities. A straightforward interpretation is that 2001 QJ142 is either an E- or M-type asteroid, although surface properties of such tiny fast-rotating asteroids are not well understood. Conclusions. We infer that 2001 QJ142 is a fast-rotating mission-accessible E- or M-type near-Earth asteroid. More characterizations of tiny asteroids are particularly important for a deeper understanding of their nature.