Structure and Magnetic Field of the Bright-rimmed Cloud IC 1396E/SFO 38

Fuente: arXiv
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Main Authors: Sugitani, Koji, Wouterloot, Jan G. A., Parsons, Harriet, Graves, Sarah, Kusune, Takayoshi, Soam, Archana
Format: Preprint
Published: 2025
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author Sugitani, Koji
Wouterloot, Jan G. A.
Parsons, Harriet
Graves, Sarah
Kusune, Takayoshi
Soam, Archana
author_facet Sugitani, Koji
Wouterloot, Jan G. A.
Parsons, Harriet
Graves, Sarah
Kusune, Takayoshi
Soam, Archana
contents We carried out polarimetric observations of the bright-rimmed cloud IC 1396E/SFO 38 with SCUBA-2/POL-2 to study the effect of ultraviolet (UV) light on its structure and magnetic field. This bright-rimmed cloud appears optically to be one single cloud illuminated by the UV light from the excited star of IC 1396, however our Stokes I image and 13CO(J=3-2) archival data suggest that this cloud is not a simple, single structure, but appears to be composed of two parts on first glance; a head part with wings and a tail, and a north-west extension part.Since molecular clouds are generally filamentary and it seems likely that the initial structures of bright-rimmed clouds are expected to be also generally elongated, we examined the possibility that the structure was created from a single elongated cloud by the UV impact. We compared the cloud structure with a simulation study that investigated the evolution of prolate clouds exposed to the UV radiation from various directions and found that this apparent two-part structure could be reproduced in a situation where a single filamentary cloud is obliquely illuminated by UV light. The magnetic field directions of the cloud are different from the ambient field direction, demonstrating the field reconfiguration. The distortion or pinch of the magnetic field is seen toward the cloud head, where an intermediate-mass star cluster is located, suggesting gravitational contraction. We roughly estimated the magnetic strength and stability in three parts of the cloud and found that the cloud head is most likely to be supercritical.
format Preprint
id arxiv_https___arxiv_org_abs_2506_14137
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Structure and Magnetic Field of the Bright-rimmed Cloud IC 1396E/SFO 38
Sugitani, Koji
Wouterloot, Jan G. A.
Parsons, Harriet
Graves, Sarah
Kusune, Takayoshi
Soam, Archana
Astrophysics of Galaxies
We carried out polarimetric observations of the bright-rimmed cloud IC 1396E/SFO 38 with SCUBA-2/POL-2 to study the effect of ultraviolet (UV) light on its structure and magnetic field. This bright-rimmed cloud appears optically to be one single cloud illuminated by the UV light from the excited star of IC 1396, however our Stokes I image and 13CO(J=3-2) archival data suggest that this cloud is not a simple, single structure, but appears to be composed of two parts on first glance; a head part with wings and a tail, and a north-west extension part.Since molecular clouds are generally filamentary and it seems likely that the initial structures of bright-rimmed clouds are expected to be also generally elongated, we examined the possibility that the structure was created from a single elongated cloud by the UV impact. We compared the cloud structure with a simulation study that investigated the evolution of prolate clouds exposed to the UV radiation from various directions and found that this apparent two-part structure could be reproduced in a situation where a single filamentary cloud is obliquely illuminated by UV light. The magnetic field directions of the cloud are different from the ambient field direction, demonstrating the field reconfiguration. The distortion or pinch of the magnetic field is seen toward the cloud head, where an intermediate-mass star cluster is located, suggesting gravitational contraction. We roughly estimated the magnetic strength and stability in three parts of the cloud and found that the cloud head is most likely to be supercritical.
title Structure and Magnetic Field of the Bright-rimmed Cloud IC 1396E/SFO 38
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2506.14137