Detection of disk accretion at the substellar limit

We have made the first definitive detection of disk accretion in an object near or below the substellar limit. We obtained an echelle-resolution spect rum of the very low mass T Tauri star V410 Anon 13; the emission-line profi le of H alpha clearly exhibits the large line width and asymmetry character istic of a free-falling accretion flow. We use magnetospheric accretion mod els of the line profile to estimate the mass accretion rate in this object, which is the smallest yet determined. We further augment this with models of the accretion shock and disk to explain the absence of both optical veil ing and an infrared excess, obtaining a firm upper limit to the accretion r ate that is consistent with the H alpha model. Our results indicate that di sk accretion via magnetospheric infall occurs even in the lowest mass young objects.