adam_core.dynamics.tisserand module

This code generates the dictionary of semi-major axes for the third body needed for the Tisserand parameter

from adam_core.orbits.query import _get_horizons_elements

ids = [“199”, “299”, “399”, “499”, “599”, “699”, “799”, “899”] elements = _get_horizons_elements(ids, times, id_type=”majorbody”)

MAJOR_BODIES = {} for i, r in elements[[“targetname”, “a”]].iterrows():

body_name = r[“targetname”].split(” “)[0].lower() MAJOR_BODIES[body_name] = r[“a”]

adam_core.dynamics.tisserand.calc_tisserand_parameter(a, e, i, third_body='jupiter')

Calculate Tisserand’s parameter used to identify potential comets. For example, objects with Tisserand parameter’s with respect to Jupiter greater than 3 are typically asteroids, whereas Jupiter family comets may have Tisserand’s parameter between 2 and 3. Damocloids have Jupiter Tisserand’s parameter of less than 2.

Parameters:

• a (float or ~numpy.ndarray (N)) – Semi-major axis in au.

• e (float or ~numpy.ndarray (N)) – Eccentricity.

• i (float or ~numpy.ndarray (N)) – Inclination in degrees.

• third_body (str) – Name of planet with respect to which Tisserand’s parameter should be calculated.

Returns:

Tp – Tisserand’s parameter.

Return type:

float or ~numpy.ndarray (N)