2004IAUC.8303....2S

T. Simon, University of Hawaii; and S. D. Brittain, E. L. Gibb, and T. W. Rettig, University of Notre Dame, report on a high- resolution Keck NIRSPEC spectrum of the near-infrared counterpart to IRAS 05436-0007 (cf. IAUC 8284). The 2-5-micron data (Feb. 27.3 UT) show a substantial amount of cold polar and apolar (cf. Ehrenfreund et al. 1997, A.Ap. 328, 649) CO ice. Initial model fits to the ice profiles are consistent with predominantly cold (< 30 K) amorphous water ice and cold, predominantly apolar CO ice (both have optical depth tau about 0.6). Also present are broadened emission lines of 12CO (1-0), (2-1), and (3-2), as well as 13CO, which likely originate from warm gas (a few thousand degrees K) in an inner accretion disk region (< 1 AU). Narrow 12CO absorption components are superposed on the underlying emission features. The narrow absorption components, with the same radial velocity as the emission lines, suggest substantial cold circumstellar material from a flared disk (cf. Brittain et al. 2004, Ap.J., submitted). In contrast to the findings published on IAUC 8301, the hydrogen lines are not strongly detected in the NIRSPEC data. The hot and cold gas surrounding the central star are typical of a young T-Tau star, but the relatively deep water and CO ice features together would be unique for the class. Both absorptions indicate that the underlying star is embedded deeply within the Orion L1630 cloud and thus at an earlier stage of evolution, very possibly a class-I object in transition.