I need some help.

[Miltonmonkey]

Hi,

I am having some problems with a comet i put into celestia in which the comet (Orbit was copied from ikeya-zhang) anyways, the closest part of the orbit is intersecting with The star.

Can anyone help?

thanks,
Miltonmonkey

[Spaceman Spiff]

Is this star bigger than our sun? Check radius of star in verbose mode ('select' the star, press v key once or twice to make Celestia verbose, look at blue text in upper left).

Otherwise:
- increase SemiMajorAxis
- reduce Eccentricity away from 1 towards 0.

Spiff.

[Miltonmonkey]

Is this star bigger than our sun? Check radius of star in verbose mode ('select' the star, press v key once or twice to make Celestia verbose, look at blue text in upper left).

Im not sure. Deneb[u] might be bigger

Otherwise:
- increase SemiMajorAxis
- reduce Eccentricity away from 1 towards 0.

Spiff.

I want to preserve the orbit

[selden]

Im not sure. [u]Deneb[u] might be bigger

Only 200x

I want to preserve the orbit

Then you'll have to pick a different star -- one that has the same mass as our sun. If its sun has a different mass, then the comet will have a different trajectory: either the SMA or the Period will have to change.

[Miltonmonkey]

I don't want to change the star, so i guess i will just do what spiff said.


thanks.

[Cham]

I want to preserve the orbit [/u]

You don't have a choice here. If you place the comet elswhere, you have to change the orbital parameters, unless the star has exactly the same mass and size as our sun.

[Spaceman Spiff]

Ooh Yes, Deneb is a huge star!

I want to preserve the orbit [/u]

If you mean you want to preserve the shape and tilt of the orbit, but scale it up to Deneb, multiply the value against the SemiMajorAxis by (as Selden says) 200?—. To be realistic, you'll have to increase the orbital period by about 630 times, assuming Deneb weighs 20 times our sun.*

Spiff.

* Or just ignore the laws of physics.