[yt-users] Stars particles

[Francia Riesco]

Hello Everybody,
  I hope you are great!
  I have a question for you
I am analyzing an Enzo data trying to get the center of mass of the 
Stars Particles. I am suing FOF

linking_length = 0.017094633
haloes = FOFHaloFinder(pf, link=linking_length ,dm_only=False)
for halo in haloes:
     ct = halo["creation_time"]
     sm = halo["ParticleMassMsun"]
     metal = halo["metallicity_fraction"]
     stars = (ct > 0)
     ct = ct[stars]
     sm = sm[stars]



Is there a way to get sm.center_of_mass()  or something similar to get 
the Center of Mass of the Stars Particles??
Thank you in Advance !