calcPeriods: Calculate eccentricity, obliquity and precession periods in...

In astrochron: A Computational Tool for Astrochronology

Calculate eccentricity, obliquity and precession periods in ka, given g, s and k in arcsec/yr

Description

Calculate eccentricity, obliquity and precession periods in ka, given g, s and k in arcsec/yr.

Usage

calcPeriods(g,s=NULL,k,opt=1,output=1)

Arguments

g	Required data frame or matrix with five columns representing the g-fundamental frequencies (g1, g2, g3, g4, g5). Frequencies must be in arcsec/yr.
s	Optional data frame or matrix with five or six columns representing the s-fundamental frequencies (five columns = s1, s2, s3, s4, s6; six columns = s1, s2, s3, s4, s5, s6). Frequencies must be in arcsec/yr. This is only required if you want to calculate obliquity periods.
k	Required data frame or vector with precession constant (frequency). Frequencies must be in arcsec/yr.
opt	(1) Calculate obliquity periods as in Laskar (1999, Table 6) (2) Calculate obliquity periods as in Malinverno and Meyers (2024, Table 1).
output	(1) return results as data frame, (2) return results as a numeric vector.

References

Laskar, J., 1999, The limits of Earth orbital calculations for geological time-scale use: Philosophical Transactions, Mathematical, Physical and Engineering Sciences, 357, 1735-1759.

Malinverno, A. and Meyers, S.R., 2024, Bayesian estimation of past astronomical frequencies, lunar distance, and length of day from sediment cycles: Geochemistry, Geophysics, Geosystems, 25, e2023GC011176.

Examples

# calculate eccentricity and precession periods for one set of g's and k
gVal= c(5.579378,7.456665,17.366595,17.910194,4.257564)
kVal= 50.475838
calcPeriods(g=gVal, k=kVal)

# calculate eccentricity and precession periods for three sets of g's and k
gVal= matrix(c(5.579378,7.456665,17.366595,17.910194,4.257564,5.494302,7.452619,
      17.480760,18.348310,4.257451,5.531285,7.456848,17.320480,17.912240,4.257456),
      nrow=3,ncol=5,byrow=TRUE)

kVal= c(50.475838,51.280910,85.790450)

calcPeriods(g=gVal, k=kVal)

astrochron documentation built on June 26, 2026, 9:09 a.m.