Definition and units of the quantities given in TEPCat






Where is …


Units and quantities

Physical constants

How many transiting planets are known?



Contact me

Physical properties of all systems

Symbol Name Unit Notes
Porb Orbital period days  
e Orbital eccentricity - These numbers are inhomogeneous: see 2011MNRAS.414.1278P. If an upper limit is available then the eccentricity will be given as 0.0 with the upper limit as the upper errorbar.
a Orbital semimajor axis AU  
Teff Effective temperature of the star Kelvin  
[Fe/H] Metal abundance of the star Logarithmic relative to the SunI adopt [M/H] where a specific [Fe/H] is not available
M* Mass of the star Msun  
R* Radius of the star Rsun  
logg Surface gravity of the star logarithmic in c.g.s. units 
ρ* Density of the star ρsun  
Mp Mass of the planet Mjup Set to 0.0 if only an upper limit is known. The upper limit is then given as the upper errorbar.
Rp Radius of the planet Rjup  
gp Surface gravity of the planet m/s2  
ρp Density of the planet ρjup Set to 0.0 if only an upper limit to the mass of the planet is known. The upper limit is then given as the upper errorbar.
Teq Equilibrium temperature of the planet Kelvin These numbers are inhomogeneous as different albedo and heat redistribution parameters are used by different people


Basic observable quantities

Symbol Name Unit Notes
Type "TEP" for a transiting planet, "CBP" for a transiting circumbinary planet, "BD" for a transiting brown dwarf, "KTEP" for a less-studied transiting planet
RA Right ascension of the target hours minutes secondsJ2000 epoch
Dec Declination of the target ±degrees minutes secondsJ2000 epoch
V V-band apparent magnitude mag  
K K-band apparent magnitude mag Usually 2MASS Ks magnitude when available
τ(4-1) Full duration of a transit days  
ΔF/F Depth of a transit percent This quantity varies slightly with wavelength due to limb darkening and light emitted from the planet
T0 Reference time of mid-transit HJD or BJD Time at which the midpoint of one particular transit occurred
Porb Orbital period days  


Orbital obliquity

Symbol Name Unit Notes
Teff Effective temperature of the star Kelvin  
λSky-projected orbital obliquity (angle between the axes of the planet's orbit and the star's spin) degreesSome studies measure the angle β instead. The two quantities are simply related by:   λ = −β
ψTrue orbital obliquity degreesψ ≥ |λ|


Last modified: 2023/01/16           John Southworth   (Keele University, UK)