Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations

We investigate the observational signatures of outflow rotation in protostellar systems using magnetohydrodynamics simulations of protostellar evolution with radiative transfer and synthetic observation. The velocity gradient perpendicular to the outflow axis indicates outflow rotation. The rotation...

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Main Authors: Yusuke Aso, Masahiro N. Machida
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adf18f
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author Yusuke Aso
Masahiro N. Machida
author_facet Yusuke Aso
Masahiro N. Machida
author_sort Yusuke Aso
collection DOAJ
description We investigate the observational signatures of outflow rotation in protostellar systems using magnetohydrodynamics simulations of protostellar evolution with radiative transfer and synthetic observation. The velocity gradient perpendicular to the outflow axis indicates outflow rotation. The rotation signature is clearly seen in the moment 1 map and a position–velocity (PV) diagram across an outflow lobe made from our model with an inclination angle of i  ≳ 85°, as in observational studies of protostellar outflows. Velocity projection with lower inclinations distorts the moment 1 map because the outflow vertical (propagation) velocity contributes more to the line-of-sight velocity, leading to an incorrect outflow axis direction. The PV diagram adopting the incorrect outflow axis shows no clear velocity gradient. These effects may prevent us from identifying outflow rotation. Our analysis implies that rotational signatures can be obscured in ∼2/3 to ∼4/5 of the total outflow population ( i  < 70°–80°), regardless of the evolutionary stage. Complicated structures in observed outflows make it difficult to determine the outflow axis, which may result in the apparent nondetection of outflow rotation.
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spelling doaj-art-e76b6a6e1d4a4e7c9e6488eb21b6f4062025-08-20T03:36:41ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01989218410.3847/1538-4357/adf18fInclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics SimulationsYusuke Aso0https://orcid.org/0000-0002-8238-7709Masahiro N. Machida1https://orcid.org/0000-0002-0963-0872Korea Astronomy and Space Science Institute , 776 Daedeok-daero, Yuseong-gu, Daejeon 34055, Republic of Korea ; yaso@kasi.re.kr; Division of Astronomy and Space Science, University of Science and Technology , 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of KoreaDepartment of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University , Fukuoka 812-8581, JapanWe investigate the observational signatures of outflow rotation in protostellar systems using magnetohydrodynamics simulations of protostellar evolution with radiative transfer and synthetic observation. The velocity gradient perpendicular to the outflow axis indicates outflow rotation. The rotation signature is clearly seen in the moment 1 map and a position–velocity (PV) diagram across an outflow lobe made from our model with an inclination angle of i  ≳ 85°, as in observational studies of protostellar outflows. Velocity projection with lower inclinations distorts the moment 1 map because the outflow vertical (propagation) velocity contributes more to the line-of-sight velocity, leading to an incorrect outflow axis direction. The PV diagram adopting the incorrect outflow axis shows no clear velocity gradient. These effects may prevent us from identifying outflow rotation. Our analysis implies that rotational signatures can be obscured in ∼2/3 to ∼4/5 of the total outflow population ( i  < 70°–80°), regardless of the evolutionary stage. Complicated structures in observed outflows make it difficult to determine the outflow axis, which may result in the apparent nondetection of outflow rotation.https://doi.org/10.3847/1538-4357/adf18fProtostarsStellar jetsMagnetohydrodynamical simulationsLow mass stars
spellingShingle Yusuke Aso
Masahiro N. Machida
Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations
The Astrophysical Journal
Protostars
Stellar jets
Magnetohydrodynamical simulations
Low mass stars
title Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations
title_full Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations
title_fullStr Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations
title_full_unstemmed Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations
title_short Inclination Effect on Observational Identification of Outflow Rotation in Magnetohydrodynamics Simulations
title_sort inclination effect on observational identification of outflow rotation in magnetohydrodynamics simulations
topic Protostars
Stellar jets
Magnetohydrodynamical simulations
Low mass stars
url https://doi.org/10.3847/1538-4357/adf18f
work_keys_str_mv AT yusukeaso inclinationeffectonobservationalidentificationofoutflowrotationinmagnetohydrodynamicssimulations
AT masahironmachida inclinationeffectonobservationalidentificationofoutflowrotationinmagnetohydrodynamicssimulations