Measuring accurate accretion rates of stellar and substellar objects will allow us to probe their fundamental formation pathways. Previous studies of excess continuum and line emission have enabled comparisons of accreting objects’ spectra across mass regimes, ranging from T Tauri stars to substellar objects. However, the differences in accretion between these objects remains unclear. We present a two-year study using the Keck Low Resolution Imaging Spectrometer (LRIS), which has broad spectral coverage spanning 3200-10000 Å. In particular, we targethoned in on a sample of six substellar objects ranging in spectral type from M5.5-M9.25 and with masses ?8-60 MJup. Our sample expands the number of substellar objects with resolved UV excess measurements substantially. Prior to our study, only four substellar objects had both spectroscopic continuum and line excess measurements, and our sample doubles this population. Our larger sample will allow us to probe the physical mechanisms producing accretion emission in substellar objects. Comprehensive characterization of accretion derived from both continuum excess and line emission is necessary to calibrate line-to-total accretion luminosity scaling relations and improve both accretion models and estimates of accretion rates. The spectral analyses from this study will aid interpretation of future protoplanet detections, as well as general understanding of the accretion physics of young protoplanets.
[Poster PDF File]