Rossiter-McLaughlin model class

The class RcmL implements the analytical model presented by Ohta et al. 2005. For an elliptical orbit, the class RmcLell can be used.

RmcL (circular orbit)

class PyAstronomy.modelSuite.RmcL

Analytical Rossiter-McLaughlin effect.

This class implements the analytical model radial velocity (RV) curves for the Rossiter-McLaughlin effect given by Ohta et. al 2005.

Fit parameters:
  • epsilon - linear limb dark

  • gamma - Rp/Rs (ratio of planetary and stellar radius)

  • P - Orbital period [d]

  • T0 - Central transit time

  • i - Inclination of orbit [rad]

  • Is - Inclination of stellar rotation axis [rad]

  • Omega - Angular rotation velocity (star) [rad/s]

  • lambda - Sky-projected angle between stellar rotation axis and normal of orbit plane [rad]

  • a - Semi major axis [stellar radii]

By default all parameters remain frozen.

Note

According to the input parameter units, the units of the model RV curve are stellar-radii per second.

Methods

MCMCautoParameters(ranges[, picky, ...])

Convenience function to generate parameters for MCMC fit.

addConditionalRestriction(*args)

Define a conditional restriction.

assignValue(specval)

Assign new values to variables.

assignValues(specval)

Assign new values to variables.

autoFitMCMC(x, y, ranges[, picky, stepsize, ...])

Convenience function to using auto-generated sampling parameters in MCMC.

availableParameters()

Provides a list of existing parameters.

delRestriction(parName)

Delete restriction

description([parenthesis])

Returns a description of the model based on the names of the individual components.

errorConfInterval(par[, dstat, statTol, ...])

Calculate confidence interval for a parameter.

evaluate(xOrig)

Calculates and returns RV curve according to current model parameters.

fit(x, y[, yerr, X0, minAlgo, mAA, ...])

Carries out a fit.

fitEMCEE([x, y, yerr, nwalker, priors, ...])

MCMC sampling using emcee package.

fitMCMC(x, y, X0, Lims, Steps[, yerr, ...])

Carry out MCMC fit/error estimation.

freeParamNames()

Get the names of the free parameters.

freeParameters()

Get names and values of free parameters.

freeze(specifiers)

Consider variables free to float.

frozenParameters()

Get names and values of frozen parameters.

getRelationsOf(specifier)

Return relations of a variable.

getRestrictions()

Get all restrictions.

hasVariable(specifier)

Determine whether the variable exists.

numberOfFreeParams()

Get number of free parameters.

parameterSummary([toScreen, prefix, sorting])

Writes a summary of the parameters in text form.

parameters()

Obtain parameter names and values.

relate(dependentVar, independentVars[, func])

Define a relation.

removeConditionalRestriction(*args)

Remove an existing conditional constraint.

renameVariable(oldName, newName)

Change name of variable.

restoreState(resource)

Restores parameter values from file or dictionary.

saveState(*args, **kwargs)

Save the state of the fitting object.

setObjectiveFunction([miniFunc])

Define the objective function.

setPenaltyFactor(penalFac)

Change the penalty factor.

setRestriction(restricts)

Define restrictions.

setRootName(root[, rename])

Define the root name of the model.

showConditionalRestrictions(**kwargs)

Show conditional restrictions.

steppar(pars, ranges[, extractFctVal, quiet])

Allows to step a parameter through a specified range.

thaw(specifiers)

Consider variables fixed.

untie(parName[, forceFree])

Remove all relations of parameter parName, i.e., the parameter is not dependend on other parameters.

updateModel()

Recalculate the model using current settings.

W1

W2

W3

W4

Xp

XpVec

Zp

etap

g

planetDistance

rho

rhoFromVec

trueAnomaly

x0

xc

z0

zeta

evaluate(xOrig)

Calculates and returns RV curve according to current model parameters.

Note

The units of the model RV curve are stellar-radii per second.

Parameters
xOrigarray

The time stamps at which to calculate the model RV curve. Note that the orbit period and central transit time are used to convert time into “true anomaly”.

RmcLell (elliptical orbit)

class PyAstronomy.modelSuite.RmcLell

Analytical Rossiter-McLaughlin effect.

This class implements the analytical model radial velocity (RV) curves for the Rossiter-McLaughlin effect given by Ohta et. al 2005.

Fit parameters:
  • epsilon - Linear limb darkening coefficient

  • gamma - Rp/Rs (ratio of planetary and stellar radius)

  • P - Orbital period [d]

  • tau - Time of periastron passage [same as orbital period]

  • i - Inclination of orbit [rad]

  • Is - Inclination of stellar rotation axis [rad]

  • Omega - Angular rotation velocity (star) [rad/s]

  • lambda - Sky-projected angle between stellar

    rotation axis and normal of orbit plane [rad]

  • a - Semi major axis [stellar radii]

  • w - Argument of periapsis [rad]

  • e - Eccentricity

Note

In the case of zero eccentricity, a value of -90 deg for the argument of periastron (w) makes the time of periastron (tau) numerically identical with the central transit time of the circular case (T0).

Note

According to the input parameter units, the units of the model RV curve are stellar-radii per second.

Methods

MCMCautoParameters(ranges[, picky, ...])

Convenience function to generate parameters for MCMC fit.

addConditionalRestriction(*args)

Define a conditional restriction.

assignValue(specval)

Assign new values to variables.

assignValues(specval)

Assign new values to variables.

autoFitMCMC(x, y, ranges[, picky, stepsize, ...])

Convenience function to using auto-generated sampling parameters in MCMC.

availableParameters()

Provides a list of existing parameters.

delRestriction(parName)

Delete restriction

description([parenthesis])

Returns a description of the model based on the names of the individual components.

errorConfInterval(par[, dstat, statTol, ...])

Calculate confidence interval for a parameter.

evaluate(xOrig)

Calculates and returns RV curve according to current model parameters.

fit(x, y[, yerr, X0, minAlgo, mAA, ...])

Carries out a fit.

fitEMCEE([x, y, yerr, nwalker, priors, ...])

MCMC sampling using emcee package.

fitMCMC(x, y, X0, Lims, Steps[, yerr, ...])

Carry out MCMC fit/error estimation.

freeParamNames()

Get the names of the free parameters.

freeParameters()

Get names and values of free parameters.

freeze(specifiers)

Consider variables free to float.

frozenParameters()

Get names and values of frozen parameters.

getRelationsOf(specifier)

Return relations of a variable.

getRestrictions()

Get all restrictions.

hasVariable(specifier)

Determine whether the variable exists.

numberOfFreeParams()

Get number of free parameters.

parameterSummary([toScreen, prefix, sorting])

Writes a summary of the parameters in text form.

parameters()

Obtain parameter names and values.

relate(dependentVar, independentVars[, func])

Define a relation.

removeConditionalRestriction(*args)

Remove an existing conditional constraint.

renameVariable(oldName, newName)

Change name of variable.

restoreState(resource)

Restores parameter values from file or dictionary.

saveState(*args, **kwargs)

Save the state of the fitting object.

setObjectiveFunction([miniFunc])

Define the objective function.

setPenaltyFactor(penalFac)

Change the penalty factor.

setRestriction(restricts)

Define restrictions.

setRootName(root[, rename])

Define the root name of the model.

showConditionalRestrictions(**kwargs)

Show conditional restrictions.

steppar(pars, ranges[, extractFctVal, quiet])

Allows to step a parameter through a specified range.

thaw(specifiers)

Consider variables fixed.

untie(parName[, forceFree])

Remove all relations of parameter parName, i.e., the parameter is not dependend on other parameters.

updateModel()

Recalculate the model using current settings.

W1

W2

W3

W4

g

evaluate(xOrig)

Calculates and returns RV curve according to current model parameters.

Note

The units of the model RV curve are stellar-radii per second.

Parameters
xOrigarray

The time stamps at which to calculate the model RV curve. Note that the orbit period and central transit time are used to convert time into “true anomaly”.