Carbon stars in IC10

Using R,I,CN and TiO filters we identify 676 carbon stars in the field of IC 10. After mapping the reddening in the field, from the colours of the G dwarfs seen along the line of sight, we determine the mean apparent magnitude of the C star population to be <I_0_>=19.78, leading to a true modulus of (m-M)_0_=24.35+/-0.11 (741+/-37kpc).

The old red giant stars define an asymmetric halo. With a halo diameter of at least 30', IC 10 is among the largest dwarfs of the Local Group. The surface density of C stars follows a radial power law with a scale length of 2.36', a value nearly identical to the scale length defined by the old giants thus IC 10 has a stellar halo where the old and intermediate-age populations are well mixed.