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M. K. Nordhaus (Rensselaer Polytechnic Institute, NRAO), Y. L. Shirley (NRAO), N. J. Evans II (Univ. of Texas), J. M. C. Rawlings (Univ. College London)
Pre-protostellar cores may represent the incipient stages of low-mass (\approx 1 Msun) star formation. Lynds 1498 is a well studied Pre-protostellar core (PPC) as it was one of the initial objects towards which molecular depletion and differentiation was detected (Kuiper, Langer, & Velusamy 1996, ApJ, 468, 761). Despite the considerable scrutiny of L1498, there has not been an extensive study of the density and temperature structure as derived from dust continuum observations. Deep SCUBA observations of L1498, obtained over two nights at 850 and 450 \mum, are presented. The emission is modeled using a one-dimensional radiative transfer code that self-consistently calculates the temperature distribution and calculates the SED and intensity profiles at 850 and 450 \mum. The model is convolved with the actual telescope beam and chopping is simulated. The ISRF is attenuated by adding between 0 and 5 magnitudes of extinction to the outer edge of the core. The best-fitted model consists of a Bonner-Ebert sphere with a central density of 104 cm-3, Av = 1 mag, and a nearly isothermal temperature profile of approximately 10.5 K. The central density is an order of magnitude lower than other modeled PPCs (Evans, Rawlings, Shirley, & Mundy 2001, ApJ, 557, 193), suggesting that L1498 may be a nascent PPC. Our temperature and density profile will improve modeling of molecular line observations and help explicate the core's kinematical and chemical state.
Funding was provided by the NSF REU Program and Rensselaer Polytechnic Institute.
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.