Investigating the Evolution of Dust Grains Within the Orion Molecular Cloud
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Authors
Nozari, Parisa
Date
Type
thesis
Language
eng
Keyword
Interestellar medium (ISM) , Dust grains , Star formation
Alternative Title
Abstract
It is assumed that dust opacities in molecular clouds follow a constant power-law
profile with an index, β. Recent studies of the Orion Molecular Cloud (OMC) 2/3
complex, however, show a flattening in the spectral energy distribution (SED) at
λ > 2 mm on core scales, implying a non-constant β. The origin of this flattening
is not yet known but amounts to elevated emission at 3.3 mm as measured by the
Green Bank Telescope by roughly a factor of 2 compared to extrapolations of shorter
wavelength (< 2 mm) data. This change in β may be due to the intrinsic properties
of the dust grains themselves or it could be due to contamination from other sources
of emission. We investigate the SED slopes in OMC 2/3 further using observations
of six protostellar cores with NOEMA from 2.9 to 3.6 mm and ALMA-ACA in Bands
4 and 5. We confirm a flattened dust opacity index at ∼ 3 mm. Such flat SEDs at
3 mm wavelengths could have profound implications for our understanding of dust
grain evolution and for how we derive masses from thermal dust emission. We discuss
these implications and propose why such elevated emission may be detected on core
scales in Orion.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
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This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-ShareAlike 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-ShareAlike 4.0 International