galpy.orbit.Orbit

class galpy.orbit.Orbit(vxvv=None, uvw=False, lb=False, radec=False, vo=None, ro=None, zo=0.025, solarmotion='hogg')

General orbit class representing an orbit

__init__(vxvv=None, uvw=False, lb=False, radec=False, vo=None, ro=None, zo=0.025, solarmotion='hogg')

NAME:

__init__

PURPOSE:

Initialize an Orbit instance

INPUT:

vxvv - initial conditions

3D can be either

1. in Galactocentric cylindrical coordinates [R,vR,vT(,z,vz,phi)]
2. [ra,dec,d,mu_ra, mu_dec,vlos] in [deg,deg,kpc,mas/yr,mas/yr,km/s] (all J2000.0; mu_ra = mu_ra * cos dec)
3. [ra,dec,d,U,V,W] in [deg,deg,kpc,km/s,km/s,kms]
4. (l,b,d,mu_l, mu_b, vlos) in [deg,deg,kpc,mas/yr,mas/yr,km/s) (all J2000.0; mu_l = mu_l * cos b)
5. [l,b,d,U,V,W] in [deg,deg,kpc,km/s,km/s,kms]

4. and 5) also work when leaving out b and mu_b/W

OPTIONAL INPUTS:

radec - if True, input is 2) (or 3) above

uvw - if True, velocities are UVW

lb - if True, input is 4) or 5) above

vo - circular velocity at ro (km/s)

ro - distance from vantage point to GC (kpc)

zo - offset toward the NGP of the Sun wrt the plane (kpc)

solarmotion - ‘hogg’ or ‘dehnen’, or ‘schoenrich’, or value in [-U,V,W]

If ro and/or vo are specified, outputs involving distances or velocities (whether as instance methods or in plots) will by default be displayed in the physical coordinates implied by these scales. This can be overwritten for each individual method by using use_physical=False as a keyword for the method.

OUTPUT:

instance

HISTORY:

2010-07-20 - Written - Bovy (NYU)