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T. W. Rettig, S. D. Brittain, E. L. Gibb (University of Notre Dame), T. Simon (University of Hawaii), C. A. Kulesa (University of Arizona), J. R. Haywood (University of Notre Dame)
Discovery of a star as it emerges from its natal cocoon of gas and dust is an extremely rare event. The infrared source IRAS 05436-0007, located in the Lynds 1630 cloud in Orion, was reported to have brightened enormously over the last couple of months; it is associated with the nebula discovered by Jay McNeil (January 23, 2004; McNeil et al. 2004). Early reports suggested the brightening resulted from a rapid accretion of circumstellar disk material infalling to the protostar similar to an FU Orionis or EX Lup event but alternative explanation might be that perhaps McNeil’s Nebula has just cleared much of the surrounding opaque material near the star to reveal a very young protostar. We obtained infrared observations of this source from 2-5 micron with NIRSPEC at the W. M. Keck Observatory. We present the discovery of hot and cold gas phase CO and H2. The broad gas phase CO emission lines indicate the presence of hot gas close to the star perhaps in a disk, and narrow CO absorption lines consistent with cooler gas in the surrounding nebulosity. The CO gas features show similarities typical of a young T-Tau star, but the relatively deep water and CO ice features (see Gibb et al. 2004) together would be unique for the class. This research is sponsored by the National Science Foundation.
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Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.