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Which precession term is that peak? One k per hypothesis.

Source: R/k_hypotheses.R
k_hypotheses.Rd

With only one or two precession cycles the assignment matters more than the measurement. This returns the precession constant and Earth-Moon state implied by reading a single cycle as each of the candidate terms.

Usage

k_hypotheses(
  period_kyr,
  age_ma,
  terms = c("k+g5", "k+g2", "k+g4", "k+g3", "k+s3"),
  method = c("angular_momentum", "astrogeo22"),
  data_dir = NULL
)

Arguments

period_kyr

Observed period of the precession (or obliquity) cycle in kyr (numeric, one value > 0). Required (no default).

age_ma

Approximate age of the record in Ma (numeric, one value); used for the obliquity of the angular-momentum inversion and for the AstroGeo22 model value that the column dk_vs_model_kyr is compared with. Required (no default).

terms

Candidate astronomical terms the cycle may represent (character vector; each must contain k), e.g. "k+g5", "k+g2", "k+g4", "k+g3", "k+s3"; one output row per term (names of a named vector become row names). Default=c("k+g5", "k+g2", "k+g4", "k+g3", "k+s3").

method

How the precession constant is converted to Earth-Moon distance and length of day (character, passed to earthmoon_state): "angular_momentum" (conservation of Earth-Moon angular momentum) or "astrogeo22" (inversion of the AstroGeo22 curve of Farhat et al., 2022). Default=c("angular_momentum", "astrogeo22"), i.e. "angular_momentum".

data_dir

Folder that contains the data tables AstroGeo22.txt and La04gisi.csv (character path). NULL uses getOption("cocoR.data") or the copies installed with WaverideR. Default=NULL.

Value

data.frame, one row per candidate term