Inclination of exoplanets

[Art Blos]

We began closely to work on exoplanets and faced such a problem.

Suppose we know the value of the inclination for the planet TRAPPIST-1 b
http://exoplanet.eu/catalog/trappist-1_b/

The database indicates that it is equal to 89.65 deg. Celestia calculates inclination of the exoplanets according to the ecliptic (in fact, it should be calculated from the picture plane).

Do need to enter value from database? If not, how to calculate the correctly?

[LukeCEL]

The 89.65-degree value is a plane-of-sky orbital element, the same type that is used for binary star orbits. To convert them to a Celestia's ecliptic system, use Grant Hutchinson's Star Orbits Spreadsheet. Simply put in the star's coordinates, the orbital period (in years), eccentricity, inclination, argument of periastron, and epoch (in Besselian years).

For basically all planets, the position angle of ascending node (Ω) is not known. This can therefore be ignored, but both the Inclination and AscendingNode parameters that are calculated have to be used.

Also, this spreadsheet was meant for semi-major axes (a) to be in arcseconds. You can ignore this too, because exoplanet.eu already lists the semi-major axis in astronomical units and you can just copy that.

As for primary transit times, I forget how to implement that.

Luke

[Art Blos]

Thank you! Exactly what is needed.