Celestia Forums

If I were to take the Solar System's invariable plane, and construct an EllipticalOrbit definition that precisely (as much as reasonably possible) matched the invariable plane, what would its Inclination, AscendingNode, ArgOfPericenter, and/or MeanAnomaly values be? And how would I figure out/calculate those values?

On a related note, how does one calculate the invariable plane of a fictitious system?

You can't use fixed Keplerian parameters (which are what are used in EllipticalOrbits) when defining orbits relative to the "invariant plane". Please reread the Position section of the Wikipedia article.

selden wrote:You can't use fixed Keplerian parameters (which are what are used in EllipticalOrbits) when defining orbits relative to the "invariant plane". Please reread the Position section of the Wikipedia article.

I'm well aware of orbital wobbling, I just wanted the EclipticJ2000 version. That is, what the invariant plane was at precisely Jan 1, 2000.

I found an article dated this year describing the calculation of the invariable plane, but it requires access from a subscriber (or subscribing library)

http://www.aanda.org/index.php?option=c ... Itemid=129

selden wrote:I found an article dated this year describing the calculation of the invariable plane, but it requires access from a subscriber (or subscribing library)

http://www.aanda.org/index.php?option=c ... Itemid=129

A remarkable paper! The authors do have a faible for numbers

Fridger

t00fri wrote:

selden wrote:I found an article dated this year describing the calculation of the invariable plane, but it requires access from a subscriber (or subscribing library)

http://www.aanda.org/index.php?option=c ... Itemid=129

A remarkable paper! The authors do have a faible for numbers

Fridger

Would the paper happen to also be on Arxiv?

PlutonianEmpire wrote:

t00fri wrote:

selden wrote:I found an article dated this year describing the calculation of the invariable plane, but it requires access from a subscriber (or subscribing library)

http://www.aanda.org/index.php?option=c ... Itemid=129

A remarkable paper! The authors do have a faible for numbers

Fridger

Would the paper happen to also be on Arxiv?

Unfortunately NO. I had already searched for it. There is a free summary, though, that contains just some of their results.

http://info.tuwien.ac.at/hg/meetings/jo ... Souami.pdf

I am entitled to access the original AA paper through my lab, but of course it is not allowed to pass such papers on. The authors essentially sum up all contributions to the total angular momentum vector of the solar system using the best available numerical ephemerides (DE405, DE406, and INPOP10a ). Once the angular momentum vector has been contructed and looks stable, the invariable plane is located orthogonal to that vector, passing through the baycenter of the solar system. This fixes the invariable plane uniquely. Since the total angular momentum vector of the solar system can be considered as a quantity that is conserved in time (<=> angular momentum conservation law!), so is the invariable plane. Hence it is best suited as a reference plane for long-time work.

What is amazing is that the inclusion of the dwarf planet Ceres and the two biggest asteroids Vesta and Pallas has significantly added to the accuracy of the determination of the invariable plane!

Fridger