  In addition to collisions and gravitational forces, it is now becoming widely
acknowledged that photon recoil forces and torques from the asymmetric
reflection and thermal re-radiation of sunlight are primary mechanisms that
govern the rotational evolution of an asteroid. The
Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect causes changes in the
rotation rate and pole direction of an irregularly shaped asteroid. We present
a simple Monte Carlo method to estimate the range of
YORP-rotational-accelerations acting on a near-Earth asteroid (NEA) without
knowledge of its detailed shape, and to estimate its detectability using
light-curve observations. The method requires knowledge of an asteroid's
orbital properties and size, and assumes that the future observational
circumstances of an asteroid have already been thought through. It is verified
by application to the observational circumstances of the seven
YORP-investigated asteroids, and is then applied to 540 NEAs with NEOWISE
and/or other diameter measurements, and to all NEAs using MPCORB absolute
magnitudes. The YORP-detectability is found to be a strong function of the
combined asteroid orbital and diameter properties, and is independent of the
rotation period for NEAs that don't have very fast or slow rotation rates. The
median and 1-sigma spread of YORP-rotational-acceleration expected to be acting
on a particular NEA can be estimated from its semimajor axis, eccentricity, and
diameter by using (eq. 1) and/or by using (eq. 2) if the diameter is instead
estimated from the absolute magnitude by assuming a geometric albedo of 0.1.
The length of a light-curve observational campaign required to achieve a 50 per
cent probability of detecting the YORP effect in a particular NEA can be
estimated by using (eq. 3) and/or by using (eq. 4) for an
absolute-magnitude-estimated diameter.
