# EXOFAST Outputs

This page describes the outputs of our applet, which fits transit and RV data using AMOEBA.

Chi^2/dof, scaling errors, RMS of residuals - The input errors are not assumed to be correct, but are scaled such that the chance of getting that chi^2 or smaller is 50%, or P(chi^2) = 0.5 (roughly chi^2/dof = 1) once the best fit is found. This is to ensure that the relative weights of RV and Transit data are appropriate.

Stellar Parameters

M* - Stellar mass, in solar masses. In fits including transits, this is derived from the transit plus logg and guided by the Torres relation (see equation 24 in Eastman, et al., 2013). If only RV is fit, we use the Torres relation alone.

R* - Stellar radius, in solar radii. In fits including transits, this is derived from the transit plus logg and guided by the Torres relation (see equation 24 in Eastman, et al., 2013). If only RV is fit, we use the Torres relation alone.

L* - Stellar luminosity, in solar luminosity.

ρ* - stellar density, in cgs. This simulateously includes the constraints from the mass/radius of the star and the transit.

logg* - The stellar surface gravity. Constained by the transit and/or its prior.

Teff - The Stellar effective temperature, in Kelvin. This is mostly constrained by the prior.

[Fe/H] - The stellar metallicity. This is mostly constrained by the prior.

Planetary Parameters

e - The eccentricity of the orbit. Not shown for circular fits.

ω* - The argument of periastron of the star's orbit, in degrees. Not shown for circular fits.

P - The period of the orbit, in days.

a - The semi-major axis of the orbit, in AU.

MP - The mass of the planet, in Jupiter masses. Not shown for RV only fits.

RP - The radius of the planet, in Jupiter radii. Not shown for RV only fits.

ρP - The density of the planet, in cgs. Not shown for RV only fits.

log(gp) - The log of the surface gravity of the planet, in cgs. Not shown for RV only fits.

Teq - The equilibrium temperature of the planet, assuming perfect redistribution and no albedo.

Θ - The Safronov number. Not shown for RV only fits.

<F> - The time-averaged incident flux that the planet receives, in units of 10^9 ergs/s/cm^2.

RV Parameters

ecosω* - eccentricity times the cosine of the argument of periastron. Not shown for circular fits.

esinω* - eccentricity times the sine of the argument of periastron. Not shown for circular fits.

TP - The time of periastron, in BJDTDB.

K - The RV semi-amplitude, in m/s. Not shown for transit-only fits.

MPsini - The minimum mass, in jupiter masses. Not shown for Transit-only fits.

MP/M* - The mass ratio of the planet to the star. Not shown for Transit-only fits.

γ - The systemic velocity (or instrumental velocity) in m/s

\dot{\gamma} - The slope in RV, in m/s/day. Only displayed if RV is fit and slope is checked.

Primary Transit Parameters

TC - The time of transit center (or time of Conjunction), in BJDTDB.

RP/R* - Radius of the planet in stellar radii. Not shown for RV only fits.

a/R* - Semi major axis in stellar radii.

i - inclination of the orbit, in degrees. Not shown for RV only fits.

b - the impact parameter. Not shown for RV only fits.

δ - (RP/R*)2, which is the transit depth for non-grazing transits with no limb darkening.

TFWHM - The duration of the Full Width at Half Maximum Transit (from mid ingress to mid egress), or the time it takes for the center of the planet to cross the entire star. For eccentric orbits, this uses the approximations of Winn, 2010. If no transit is fit, we assume a point planet (RP=0) and a central crossing (b=0), and therefore TFWHM is not displayed because it equals T14.

τ - the duration of ingress/egrees (1st to 2nd contact or 3rd to 4th contact). For eccentric orbits, this uses the approximations of Winn, 2010. If no transit is fit, we assume a point planet (RP=0) and a central crossing (b=0) and therefore τ is not displayed because it is equal to 0.

T14 - The duration of transit (1st to 4th contact). For eccentric orbits, this uses the approximations of Winn, 2010. If no transit is fit, we assume a point planet (RP=0) and a central crossing (b=0).

PT - The a priori non-grazing transit probability, assuming no knowledge of the inclination. If no transit is fit, we assume a point planet (RP=0); and therefore PT = PT,G. This is useful for transit searches of RV planets or to correct for geometric biases for transiting planets.

PT,G - The a priori grazing transit probability, assuming no knowledge of the inclination.

u1 - The linear limb darkening coefficient.

u2 - The quadratic limb darkening coefficient.

F0 - The average out-of-transit flux. Should be close to 1 (and in the figure, it is exactly equal to 1).

Secondary Eclipse Parameters

TS - The time of secondary eclipse center in BJDTDB.

bS - The impact parameter for the secondary eclipse. Only shown if eccentricity is free (otherwise it's identical to the primary).

TS,FWHM - The duration of the Full Width at Half Maximum of the eclipse (from mid ingress to mid egress), or the time it takes for the center of the planet to cross the entire star. Only shown if eccentricity is free (otherwise it's identical to the primary). We use the approximations of Winn, 2010. If no transit is fit, we assume a point planet (RP=0) and a central crossing (b=0).

τS - the duration of ingress/egrees (1st to 2nd contact or 3rd to 4th contact). Only shown if eccentricity is free (otherwise it's identical to the primary). We use the approximations of Winn, 2010. If no transit is fit, we assume a point planet (RP=0) and a central crossing (b=0).

TS,14 - The duration of eclipse (1st to 4th contact). Only shown if eccentricity is free (otherwise it's identical to the primary). We use the approximations of Winn, 2010. If no transit is fit, we assume a point planet (RP=0) and a central crossing (b=0).

PS - The a priori non-grazing eclipse probability, assuming no knowledge of the inclination. To determine posterior eclipse probablity: bS < 1-p => eclipse. Only shown if eccentricity is free (otherwise it's identical to the primary).

PS,G - The a priori grazing eclipse probability, assuming no knowledge of the inclination. To determine posterior eclipse probablity: bS < 1+p => eclipse. shown if eccentricity is free (otherwise it's identical to the primary).

NOTE: The times are only in BJDTDB if the input times are in BJDTDB, as required by the input.