SIMBAD references

We report an accurate distance of d=10±2.5 kpc to the high-velocity cloud Complex C. Using high signal-to-noise ratio Keck HIRES spectra of two horizontal-branch stars, we have detected Ca II K absorption lines from the cloud. Significant nondetections toward a further three stars yield robust lower distance limits. The resulting H I mass of Complex C is M_HI_=4.9+2.9-2.2_x10⁶ M_☉; a total mass of M_tot=8.2^+4.6_–2.6x10⁶ M_☉ is implied, after corrections for helium and ionization. At 10 kpc, Complex C has physical dimensions 3x15 kpc, and if it is as thick as it is wide, then the average density is log<n≥~-2.5. We estimate the contribution of Complex C to the mass influx may be as high as ∼0.14 M_☉/yr.