Create a generalized EOM solution that allows e >=1 (hyperbolic and parabolic orbits)

[sealauren]

Idea from Eric Agol: allow exploration of hyperbolic orbits. This might be important in the Gaia era.

We currently use the Danby method to solve Kepler’s equation, but this only applies for e < 1. The paper below (Wisdom & Hernandez 2015) derives a more general solution that can be applied to hyperbolic and parabolic orbits.

https://watermark.silverchair.com/stv1862.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAkUwggJBBgkqhkiG9w0BBwagggIyMIICLgIBADCCAicGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMB5iPBf_jvqZAKPFVAgEQgIIB-ACXTIq4tIzplu3iYu5CH9lkvANpOpsyzhuCUSoELQdw-W8ePstHzV13OUp9VlZPPiWyShGpjAvYDvw-djnSq7G1QiHtFAguFHBKaGL_wA1G_GCjnqsLUP5Ml4YumulnmJR_wuI6shPmuGTlXgfm1BEnOxm0QdKqCcY2Z4-YnpMOQXqmpobJcn26Gorhpth3pA2EdDQd1azrrcrMZ9cdVdxI07ZqVmovC0vwrN-FN-eWPs3qeBaRSHTZ3nBQbMWC0gNuc24NvqpnXR_icXyxi0talAHCrsT-chf5RYmry8AwArTdKscomxjduV542M8GTjUH8DpA0C7lpzeOByL_v8Iwi2QKMXUp34lEHYl6Ip0kRUoDTvVCXapAmOYtoeeMXXHQGkJCZ4YHToonXrimA4BFxmkJgiUaWOuyt4wCetakBqVAqy8xWmtXrUQh3UybRqqZHBfaSFo-vq8pVShrqGmlePszwxC4tP53T3p5wWUPRKZRr1PDbvlV1RHSV-uG0RxpKVfiNvedgvLjrGhlvryW6U18KdjxhlXq4YtyLXOkOAbVowl0cE6Jf0Lbxzs2__dmR_TuS_ugdw6V1REgDp5JQirxNkVMP9GN6RENTecvDgZkDG89WLbm99gk4tph-JTyJa4ETWdJEVX-osrWWIDLLQfwt3ccmg