The Flattest Infrared Extinction Curve in Four Isolated Dense Molecular Cloud Cores

Fuente: arXiv
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Main Authors: Li, Jun, Chen, Bingqiu, Jiang, Biwei, Zhao, He, Jiang, Botao, Chen, Xi
Format: Preprint
Published: 2024
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author Li, Jun
Chen, Bingqiu
Jiang, Biwei
Zhao, He
Jiang, Botao
Chen, Xi
author_facet Li, Jun
Chen, Bingqiu
Jiang, Biwei
Zhao, He
Jiang, Botao
Chen, Xi
contents The extinction curve of interstellar dust in the dense molecular cloud cores is crucial for understanding dust properties, particularly size distribution and composition. We investigate the infrared extinction law in four nearby isolated molecular cloud cores, L429, L483, L673, and L1165, across the 1.2 - 8.0 $μ$m wavelength range, using deep near-infrared (NIR) and mid-infrared (MIR) photometric data from UKIDSS and Spitzer Space Telescope. These observations probe an unprecedented extinction depth, reaching $A_V\sim$ 40-60 mag in these dense cloud cores. We derive color-excess ratios $E(K-λ)/E(H-K)$ by fitting color-color diagrams of $(K-λ)$ versus $(H-K)$, which are subsequently used to calculate the extinction law $A_λ/A_K$. Our analysis reveals remarkably similar and exceptionally flat infrared extinction curves for all four cloud cores, exhibiting the most pronounced flattening reported in the literature to date. This flatness is consistent with the presence of large dust grains, suggesting significant grain growth in dense environments. Intriguingly, our findings align closely with the Astrodust model for a diffuse interstellar environment proposed by Hensley \& Draine. This agreement between dense core observations and a diffuse medium model highlights the complexity of dust evolution and the need for further investigation into the processes governing dust properties in different interstellar environments.
format Preprint
id arxiv_https___arxiv_org_abs_2411_00619
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Flattest Infrared Extinction Curve in Four Isolated Dense Molecular Cloud Cores
Li, Jun
Chen, Bingqiu
Jiang, Biwei
Zhao, He
Jiang, Botao
Chen, Xi
Astrophysics of Galaxies
Solar and Stellar Astrophysics
The extinction curve of interstellar dust in the dense molecular cloud cores is crucial for understanding dust properties, particularly size distribution and composition. We investigate the infrared extinction law in four nearby isolated molecular cloud cores, L429, L483, L673, and L1165, across the 1.2 - 8.0 $μ$m wavelength range, using deep near-infrared (NIR) and mid-infrared (MIR) photometric data from UKIDSS and Spitzer Space Telescope. These observations probe an unprecedented extinction depth, reaching $A_V\sim$ 40-60 mag in these dense cloud cores. We derive color-excess ratios $E(K-λ)/E(H-K)$ by fitting color-color diagrams of $(K-λ)$ versus $(H-K)$, which are subsequently used to calculate the extinction law $A_λ/A_K$. Our analysis reveals remarkably similar and exceptionally flat infrared extinction curves for all four cloud cores, exhibiting the most pronounced flattening reported in the literature to date. This flatness is consistent with the presence of large dust grains, suggesting significant grain growth in dense environments. Intriguingly, our findings align closely with the Astrodust model for a diffuse interstellar environment proposed by Hensley \& Draine. This agreement between dense core observations and a diffuse medium model highlights the complexity of dust evolution and the need for further investigation into the processes governing dust properties in different interstellar environments.
title The Flattest Infrared Extinction Curve in Four Isolated Dense Molecular Cloud Cores
topic Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2411.00619