Why does this code, using astropy LSR, give the same result in RV despite differing proper motions, i.e. 8.2802 km/s? I would expect that a change in proper motion should have an influence in the second case (GalacticLSR). Thank you
from astropy.coordinates import LSR from astropy.coordinates import SkyCoord, ICRS, Galactocentric star1 = ICRS(ra=84.053*u.deg, dec=-1.202*u.deg, distance=384*u.pc, pm_ra_cosdec=2*u.mas/u.yr, pm_dec=-0.5*u.mas/u.yr, radial_velocity=25*u.km/u.s) lsr1 = star1.transform_to(GalacticLSR()) # Case 2: Large proper motion star2 = ICRS(ra=84.053*u.deg, dec=-1.202*u.deg, distance=384*u.pc, pm_ra_cosdec=300*u.mas/u.yr, pm_dec=500*u.mas/u.yr, radial_velocity=25*u.km/u.s) lsr2 = star2.transform_to(GalacticLSR()) # Print results print(f"Low PM, LSR radial velocity: {lsr1.radial_velocity:.4f}") print(f"High PM, LSR radial velocity: {lsr2.radial_velocity:.4f}") 
