Asteroid astrometry as a fifth-force and ultralight dark sector probe
  We study for the first time the possibility of probing long-range fifth
forces utilizing asteroid astrometric data, via the fifth force-induced orbital
precession. We examine nine Near-Earth Object (NEO) asteroids whose orbital
trajectories are accurately determined via optical and radar astrometry.
Focusing on a Yukawa-type potential mediated by a new gauge field (dark photon)
or a baryon-coupled scalar, we estimate the sensitivity reach for the
fifth-force coupling strength and mediator mass in the mass range $m \simeq
10^{-21}-10^{-15}\,{\rm eV}$. Our estimated sensitivity is comparable to
leading limits from torsion balance experiments, potentially exceeding these in
a specific mass range. The fifth forced-induced precession increases with the
orbital semi-major axis in the small $m$ limit, motivating the study of objects
further away from the Sun. We discuss future exciting prospects for extending
our study to more than a million asteroids (including NEOs, main-belt
asteroids, Hildas, and Jupiter Trojans), as well as trans-Neptunian objects and
exoplanets.
