From Stardust to Planetesimals: Contributed Papers - NASA Lunar ...

AN INFRARED STUDY OF THE JUGGLER NEBULAJ. C. HOLBROOK University of California, Santa Cruz, California, USAP. TEMI University of California, Santa Cruz, California, USAD. RANK ' University of California, Santa Cruz, California, USAJ. BREGMAN NASA Ames Research Center, MS 215-6, Moffet Field, CA91035-1000ABSTRACT. This work is an examination of the infrared reflection nebula surroundinga protostellar source, IRS 1, in the CRL 2136 region at 2.2, 3.08, and 3.45µm. The greatest absorption due to water ice occurs within 5 aresec (10,000 AU, D= 2000pc of IRS 1. The water ice absorption decreases with increasing radius fromIRS 1. his ri,, structure suggests that the water ice is primarily associated withIRS 1. The flux from IRS 1 has a [2.2] - [3.45] color of 5, much redder than thenebula. The color structure combined with the ri,, structure suggests the presence ofan icy-dusty disk around IRS 1 orientated NE to SW. Radio CO maps presented byKastner et al. (1994) reveal a molecular outflow orientated perpendicular to the disk.The south and east reflection lobes line the conical cavity created by the blueshiftedmolecular outflow.1. INTRODUCTIONPrevious studies of GL 2136 (1950: 18 19 39.3 -13 3118) reveal a protostellar object,IRS 1 (Lti 7.2 x 10 3 L (D ) which is the source of a massive molecular outflow (Kastner1994). At near infrared wavelengths, three reflection lobes are visible which give theregion its name: The Juggler Nebula. The polarization at 2.2 tim has an ellipticalstructure which suggests the presence of a disk around IRS 1 and that IRS 1 is thesole illuminating source for the reflection nebula (Minchin 1991, Kastner 1992).The spectral energy distribution of GL 2136 has a prominent absorption featureat 3.08 µm due to water ice (Willner 1982). The polarization study of Hough etal. (1989) concludes that the near infrared continuum in the nebula arises from alignedgrains and that the polarization in the `ice band' arises from icy grains which are notuniformly distributed along the line-of-sight towards IRS 1. Kastner et al.(1992)propose that the water ice absorption originates from a circumstellar disk aroundIRS 1.This paper presents the M2.2 - M3.45 color structure and the water ice, Ti,,, absorptionstructure of GL 2136. The 2.2 µm data is compared to a simple single scatteringcalculation. The implications of the color and Tice maps and the single scatteringanalysis are discussed in §3. The conclusions are presented in §4.41