Mid-infrared imaging of Orion BN/KL. II. Luminosity sources, extinction distribution, and the nature of IRc2

Citation
Dy. Gezari et al., Mid-infrared imaging of Orion BN/KL. II. Luminosity sources, extinction distribution, and the nature of IRc2, ASTROPHYS J, 509(1), 1998, pp. 283-298
Citations number
48
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
509
Issue
1
Year of publication
1998
Part
1
Pages
283 - 298
Database
ISI
SICI code
0004-637X(199812)509:1<283:MIOOBI>2.0.ZU;2-G
Abstract
We have recalculated the luminosities of IRc2 and the BN Object in the Orio n BN/KL complex and determined the distributions of color temperature and s ilicate absorption-line strength over the region with much greater precisio n than before, using a complete set of well-sampled and nearly diffraction- limited array camera images of BN/KL at nine wavelengths between 4.8 and 20 mu m. We find that the total infrared luminosity of IRc2 itself is only L similar to 1000 L. (much lower than the generally accepted value). However, the temperature and extinction distributions show that the significant lum inosity source(s) in BN/KL must still be located within several arcseconds of IRc2. Our results, considered with recent radio continuum and maser emis sion observations, suggest that a luminous early-type star located at radio source "I" is embedded close to IRc2, obscured by similar to 60 mag of vis ual extinction from dust grains both local to IRc2 and in intervening cloud s along the line of sight. The combined heating contributions of the hot st ars ionizing the compact H II regions "I" (near IRc2), "B" (the BN Object), and "L" (infrared source "n"), compact IRc objects (including 10 new peaks resolved here), and distributed near-infrared sources can account for the observed similar to 10(5) L. total luminosity of the BN/KL complex.