Luni-solar precession frequency (Farhat et al. 2022, eq. A.7)

Usage

precession_frequency(
  a_RE,
  lod_h = NULL,
  obliquity_deg = .AC$obliquity0_deg,
  Ed = .AC$Ed0,
  lod_kind = "solar"
)

a_RE: Earth-Moon distance in Earth radii (numeric, > 0; the present value is about 60.14). Required, no default. It sets the lunar part of the precession torque and, when lod_h = NULL, the length of day.
lod_h: Length of day in hours (numeric, > 0), of the type given by lod_kind. NULL derives the Earth's spin rate from a_RE by conservation of the angular momentum of the Earth-Moon system (omega_from_moon_distance). Default=NULL.
obliquity_deg: Earth's obliquity in degrees (numeric); the precession rate scales with its cosine. Default=.AC$obliquity0_deg, the present value of 23.2545 degrees.
Ed: Dynamical ellipticity of the Earth at the present spin rate (numeric, dimensionless); it is scaled with the square of the spin rate. Default=.AC$Ed0, i.e. 0.003243.
lod_kind: Type of day of lod_h (character): "solar" or "sidereal"; also used for the length of day returned. Default="solar".

list: p in arcsec/yr and the precession period in kyr