C/2006 A1 "calc"

[symaski62]

Code: Select all

"C/2006 A1" "Sol"
{
Class "comet"
Texture "asteroid.jpg"
Mesh "asteroid.cms"
Radius 5

EllipticalOrbit
 {
 Period ???? #calculated: (q/(1-e))^1.5
 PericenterDistance 0.555405007052757
 Eccentricity 1
 Inclination 92.7398026068976
 AscendingNode 211.341862238783
 ArgOfPericenter 351.18629543621
 MeanAnomaly 0.0
 Epoch 2453754.5
 }
}

#calculated: (q/(1-e))^1.5

?!?

[GlobeMaker]

http://www.lns.cornell.edu/~seb/celesti ... eters.html

q pericenter

e eccentricity

1.5 = 3/2

[symaski62]

http://www.lns.cornell.edu/~seb/celestia/orbital-parameters.html

q pericenter

e eccentricity

1.5 = 3/2

pericenter 0.5554
eccentricity 1

(0.5554/(1-1))^1.5 = 0

[GlobeMaker]

A parabola has an eccentricity of 1.

[Adirondack]

In other words:

If eccentricity = or > 1 the comet will never come back, so there is no period!

[selden]

Celestia requires that you specify a Period.

# For a closed, elliptical solar orbit,
P = sqrt (( q / ( 1 - e)) ^3)
or = a^1.5


P = 1/n = 1/ Mean Motion


For an open, hyperbolic orbit, one can use
P = sqrt (( q / ( e - 1)) ^3)

where P is the period measured in years
q is the pericenter measured in AU
e is the eccentricity
and a is the semimajor axis of the orbit, also measured in AU (which has a negative value for hyperbolic orbits).

Thanks to Grant Hutchison for explaining this.