СПЕКТРИ ВІДБИВАННЯ РІЗНИХ ДІЛЯНОК ПОВЕРХНІ В ОБЛАСТІ КРАТЕРА МАРСІЯ НА ВЕСТІ

The pre-equatorial Marcia crater on asteroid (4) Vesta represents one of the youngest and best-preserved impact structures on the body, distinguished by its complex morphology and strong spectral variability. Within the Av-8 Marcia quadrangle, two spectrally and morphologically distinct surface units — pitted impact deposits (PIDs) and orange material patches (OMPs) — dominate the region and provide valuable insights into post-impact surface evolution. Using calibrated Framing Camera (FC) images from NASA’s Dawn mission obtained during HAMO and LAMO phases, we analyzed the spectral characteristics of these units through color-ratio imaging (C(438 nm/749 nm) and C(749 nm/917 nm)) and reflectance spectra derived from Level 1b datasets. Results show that both PIDs and OMPs display higher albedo, redder spectral slopes, and deeper 0.9 μm pyroxene bands relative to surrounding materials, yet their spectral signatures differ markedly. PIDs generally exhibit deeper 0.9 μm absorption bands and broader reflectance variability, while OMPs display consistently redder slopes and lower reflectance at 438 nm. Spatially, OMPs and PIDs frequently co-occur in the southwestern vicinity of Marcia crater, where lobate, flowlike morphologies also appear. Our findings confirm that simultaneous examination of C(438 nm/749 nm) and C(749 nm/917 nm) color-ratio maps is an effective approach to discriminate between OMPs and PIDs.