Help Page for Custom Transit Ephemerides
Period
The orbital period of the planet in calendar days.
Period Uncertainty
This reflects the observational uncertainty in the determination of the orbital period, and is measured in calendar days. Decreasing this value produces an ephemeris whose transit window approaches the actual transit duration.
Periastron Epoch
The pericenter epoch is the time, expressed as a Julian date, when the planet passed through the periastron of its orbit.
Uncertainty in Periastron Epoch
This reflects the observational uncertainty in when the planet passed through periastron, measured in days.
Planet Radius
The radius of the planet, expressed in units of Jupiter radii.
Semimajor Axis
The semimajor axis of the planetary orbit about its host star, expressed in Astronomical Units (au).
Longitude of Periastron
The longitude separation between the ascending node of the orbit and the location in the orbit of periastron.
Eccentricity
The eccentricity of the planetary orbit around its host star.
Star Radius
The stellar radius, expressed in units of Solar radii. Note that some giant stars (e.g., 14 Andromedae) harbor planets but do not have well-defined radii, making accurate orbital ephemeris prediction difficult.
Inclination
This is the inclination of the planet's orbital plane to the line of sight. Note that observational limitations largely restrict this parameter to a few degrees from 90.
Transit Duration
The duration of the planet's transit across its host star.
Transit Duration Uncertainty
The positive and negative uncertainties in the duration of the planet's transit across its host star.
Transit Midpoint
The epoch of the midpoint of the planet's transit, expressed as a Julian date.
Transit Midpoint Uncertainty
The uncertainty in the midpoint epoch, expressed in days.
