Mon R2: A Hub–Filament System with an Infrared Bubble at the Hub Center
A multiwavelength, multiscale study of the Mon R2 hub–filament system (HFS) reveals a spiral structure, with the central hub containing more mass than its filaments. C ^18 O(1–0) emission detected by the Atacama Large Millimeter/submillimeter Array (ALMA) reveals several accreting filaments connecte...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-3881/ad9b22 |
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| Summary: | A multiwavelength, multiscale study of the Mon R2 hub–filament system (HFS) reveals a spiral structure, with the central hub containing more mass than its filaments. C ^18 O(1–0) emission detected by the Atacama Large Millimeter/submillimeter Array (ALMA) reveals several accreting filaments connected to a molecular ring (size ∼0.18 pc × 0.26 pc). The molecular ring surrounds the infrared (IR) ring (size ~0.12 pc × 0.16 pc), which is not usually observed. The IR ring encircles IR-quiet regions and a population of embedded near-IR sources, including the massive stars IRS 1 and IRS 2. ALMA HNC(3–2) line data reveal a mirrored B-shaped feature (extent ∼19,000 au × 39,000 au) toward the eastern part of the molecular ring, suggesting expansion at ~2.25 km s ^−1 . Distinct HNC substructures in both redshifted and blueshifted velocity components are investigated toward the B-shaped feature. The presence of these braid-like substructures in each velocity component strongly suggests instability in photon-dominated regions. A dusty shell-like feature (extent ~0.04 pc × 0.07 pc; mass ~7 M _⊙ ) hosting IRS 1 is identified in the ALMA 1.14 mm continuum map, centered toward the base of the B-shaped feature. The IR and dense molecular rings are likely shaped by feedback from massive stars, driven by high pressures of between 10 ^−8 and 10 ^−10 dyn cm ^−2 , observed within a 1 pc range of the B0 zero-age main-sequence star powering the ultracompact H ii region. Overall, these outcomes support the idea that the Mon R2 HFS transitioned from IR-quiet to IR-bright, driven by the interaction between gas accretion and feedback from massive stars. |
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| ISSN: | 1538-3881 |