System parameters (sys.yaml)

The sys.yaml file defines the host star and planet properties used as priors.

Example

star:
  teff: [5675, 75]
  logg: [4.2, 0.2]
  feh: [0.0, 0.5]
  mass: [1.22, 0.05]
  radius: [1.38, 0.06]
planets:
  b:
    t0: [2458604.02371, 0.00037]
    period: [6.959503, 0.000016]
    ror: [0.0667, 0.0012]
    b: [0.134, 0.1]
    dur: [0.201, 0.001]

Star

All stellar parameters are specified as [value, uncertainty].

Parameter	Description	Required
teff	Effective temperature [K]	Always (for limb darkening)
logg	Surface gravity [cgs]	Always (for limb darkening)
feh	Metallicity [dex]	Always (for limb darkening)
mass	Stellar mass [M_sun]	Only if fit_basis: mstar/rstar
radius	Stellar radius [R_sun]	Only if fit_basis: mstar/rstar

Note

For the default fit_basis: duration, mass and radius are optional. The three spectroscopic parameters (teff, logg, feh) are always required because they are used to compute theoretical limb darkening coefficients.

Planets

Each planet is listed under planets: with a letter key (e.g., b, c). All parameters are specified as [value, uncertainty].

Parameter	Description
t0	Reference transit time [BJD]
period	Orbital period [days]
ror	Planet-to-star radius ratio (Rp/R*)
b	Impact parameter
dur	Transit duration [days]

You can define multiple planets in the same file:

planets:
  b:
    t0: [2458604.02371, 0.00037]
    period: [6.959503, 0.000016]
    ror: [0.0667, 0.0012]
    b: [0.134, 0.1]
    dur: [0.201, 0.001]
  c:
    t0: [2458602.5025, 0.0022]
    period: [14.334894, 0.00003]
    ror: [0.0517, 0.0042]
    b: [0.15, 0.15]
    dur: [0.2348, 0.0028]

Only the planets listed in fit.yaml's planets field will be included in the fit.