IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment
We present a near-infrared spectroscopic and imaging analysis of the star-forming region IRAS 16475−4609, based on TripleSpec/SOAR spectroscopy and NEWFIRM/CTIO imaging, complemented by archival radio and submillimeter data. Our spectroscopic analysis indicates that the central source is an early B-...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astronomical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-3881/ade98a |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849245966358544384 |
|---|---|
| author | Felipe Navarete Sean D. Points Augusto Damineli |
| author_facet | Felipe Navarete Sean D. Points Augusto Damineli |
| author_sort | Felipe Navarete |
| collection | DOAJ |
| description | We present a near-infrared spectroscopic and imaging analysis of the star-forming region IRAS 16475−4609, based on TripleSpec/SOAR spectroscopy and NEWFIRM/CTIO imaging, complemented by archival radio and submillimeter data. Our spectroscopic analysis indicates that the central source is an early B-type star (B0–B0.7 V) powering a compact H ii region characterized by strong H i and He i recombination lines, and molecular H _2 emission. We derive a distance of 3.51 ± 0.74 kpc, consistent with the position of the Scutum–Crux near arm at a Galactic longitude of ∼340 ^∘ . At this distance, the ionized gas traced by Br γ emission has a radius of 0.27 ± 0.06 pc, placing the source in a transition phase between ultracompact and compact H ii regions. From radio data, we estimate an ionizing photon flux of N _Ly = (2.3 ± 0.3) × 10 ^47 photons s ^−1 , and an electron temperature of T _e = (5.4 ± 0.2) × 10 ^3 K for the ionized gas. The analysis also reveals an obscured high-density molecular clump SW of the H ii region, coincident with an ATLASGAL submillimeter peak, indicating a potential site of ongoing and triggered star formation as the ionization front advances into the surrounding molecular material. These results suggest that IRAS 16475−4609 is a young high-mass star-forming region with stellar feedback actively shaping its environment, offering valuable insight into the early evolution of compact H ii regions. |
| format | Article |
| id | doaj-art-69fef394f29c47019590018bfd400172 |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-69fef394f29c47019590018bfd4001722025-08-20T03:58:39ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01170212110.3847/1538-3881/ade98aIRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular EnvironmentFelipe Navarete0https://orcid.org/0000-0002-0284-0578Sean D. Points1https://orcid.org/0000-0002-4596-1337Augusto Damineli2https://orcid.org/0000-0002-7978-2994Laboratório Nacional de Astrofísica , Rua dos Estados Unidos 154, 37504-364 Itajubá, MG, Brazil ; fnavarete@lna.br; NSF’s NOIRLab/SOAR Telescope , Casilla 603, La Serena 1700000, ChileNSF’s NOIRLab/CTIO , Casilla 603, La Serena 1700000, ChileInstituto de Astronomia, Geofísica e Ciências Atmosféricas da USP, Rua do Matão 1226, Cidade Universitária , 05508-090, São Paulo, SP, BrazilWe present a near-infrared spectroscopic and imaging analysis of the star-forming region IRAS 16475−4609, based on TripleSpec/SOAR spectroscopy and NEWFIRM/CTIO imaging, complemented by archival radio and submillimeter data. Our spectroscopic analysis indicates that the central source is an early B-type star (B0–B0.7 V) powering a compact H ii region characterized by strong H i and He i recombination lines, and molecular H _2 emission. We derive a distance of 3.51 ± 0.74 kpc, consistent with the position of the Scutum–Crux near arm at a Galactic longitude of ∼340 ^∘ . At this distance, the ionized gas traced by Br γ emission has a radius of 0.27 ± 0.06 pc, placing the source in a transition phase between ultracompact and compact H ii regions. From radio data, we estimate an ionizing photon flux of N _Ly = (2.3 ± 0.3) × 10 ^47 photons s ^−1 , and an electron temperature of T _e = (5.4 ± 0.2) × 10 ^3 K for the ionized gas. The analysis also reveals an obscured high-density molecular clump SW of the H ii region, coincident with an ATLASGAL submillimeter peak, indicating a potential site of ongoing and triggered star formation as the ionization front advances into the surrounding molecular material. These results suggest that IRAS 16475−4609 is a young high-mass star-forming region with stellar feedback actively shaping its environment, offering valuable insight into the early evolution of compact H ii regions.https://doi.org/10.3847/1538-3881/ade98aMassive starsStellar distanceH II regionsInterstellar mediumSpectroscopy |
| spellingShingle | Felipe Navarete Sean D. Points Augusto Damineli IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment The Astronomical Journal Massive stars Stellar distance H II regions Interstellar medium Spectroscopy |
| title | IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment |
| title_full | IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment |
| title_fullStr | IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment |
| title_full_unstemmed | IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment |
| title_short | IRAS 16475–4609: A Young Compact H II Region Sculpting its Molecular Environment |
| title_sort | iras 16475 4609 a young compact h ii region sculpting its molecular environment |
| topic | Massive stars Stellar distance H II regions Interstellar medium Spectroscopy |
| url | https://doi.org/10.3847/1538-3881/ade98a |
| work_keys_str_mv | AT felipenavarete iras164754609ayoungcompacthiiregionsculptingitsmolecularenvironment AT seandpoints iras164754609ayoungcompacthiiregionsculptingitsmolecularenvironment AT augustodamineli iras164754609ayoungcompacthiiregionsculptingitsmolecularenvironment |