VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate
We use 3 mm continuum NOrthern Extended Millimeter Array and NH _3 Very Large Array observations toward the First Hydrostatic Core (FHSC) candidate CB 17 MMS in order to reveal the dust structure and gas properties to 600–1100 au scales and to constrain its evolutionary stage. We do not detect any c...
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| Format: | Article |
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IOP Publishing
2021-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ac3083 |
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| author | Stephanie Spear María José Maureira Héctor G. Arce Jaime E. Pineda Michael Dunham Paola Caselli Dominique Segura-Cox |
| author_facet | Stephanie Spear María José Maureira Héctor G. Arce Jaime E. Pineda Michael Dunham Paola Caselli Dominique Segura-Cox |
| author_sort | Stephanie Spear |
| collection | DOAJ |
| description | We use 3 mm continuum NOrthern Extended Millimeter Array and NH _3 Very Large Array observations toward the First Hydrostatic Core (FHSC) candidate CB 17 MMS in order to reveal the dust structure and gas properties to 600–1100 au scales and to constrain its evolutionary stage. We do not detect any compact source at the previously identified 1.3 mm point source, despite expecting a minimum signal-to-noise ratio of 9. The gas traced by NH _3 exhibits subsonic motions, with an average temperature of 10.4 K. A fit of the radial column density profile derived from the ammonia emission finds a flat inner region of radius ∼1800 au and a central density of ∼6 × 10 ^5 cm ^−3 . Virial and density structure analysis reveals the core is marginally bound ( α _vir = 0.73). The region is entirely consistent with that of a young starless core, hence ruling out CB 17 MMS as an FHSC candidate. Additionally, the core exhibits a velocity gradient aligned with the major axis, showing an arc-like structure in the position–velocity diagram and an off-center region with high velocity dispersion, caused by two distinct velocity peaks. These features could be due to interactions with the nearby outflow, which appears to deflect due to the dense gas near the NH _3 column density peak. We investigate the specific angular momentum profile of the starless core, finding that it aligns closely with previous studies of similar radial profiles in Class 0 sources. This similarity to more evolved objects suggests that motions at 1000 au scales are determined by large-scale dense cloud motions, and may be preserved throughout the early stages of star formation. |
| first_indexed | 2024-03-08T05:45:41Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-08T05:45:41Z |
| publishDate | 2021-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-63245a93cd634f6c9eec78361d0722172024-02-05T09:07:42ZengIOP PublishingThe Astrophysical Journal1538-43572021-01-01923223110.3847/1538-4357/ac3083VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core CandidateStephanie Spear0https://orcid.org/0009-0005-6280-0104María José Maureira1https://orcid.org/0000-0002-7026-8163Héctor G. Arce2https://orcid.org/0000-0001-5653-7817Jaime E. Pineda3https://orcid.org/0000-0002-3972-1978Michael Dunham4https://orcid.org/0000-0003-0749-9505Paola Caselli5https://orcid.org/0000-0003-1481-7911Dominique Segura-Cox6https://orcid.org/0000-0003-3172-6763Department of Astronomy, Yale University , New Haven, CT 06511, USA ; stephanie.spear@aya.yale.eduMax-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, GermanyDepartment of Astronomy, Yale University , New Haven, CT 06511, USA ; stephanie.spear@aya.yale.eduMax-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, GermanyCenter for Astrophysics ∣ Harvard & Smithsonian , Cambridge, MA 02138, USA; Department of Physics, State University of New York Fredonia , Fredonia, NY 14063, USAMax-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, GermanyMax-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, GermanyWe use 3 mm continuum NOrthern Extended Millimeter Array and NH _3 Very Large Array observations toward the First Hydrostatic Core (FHSC) candidate CB 17 MMS in order to reveal the dust structure and gas properties to 600–1100 au scales and to constrain its evolutionary stage. We do not detect any compact source at the previously identified 1.3 mm point source, despite expecting a minimum signal-to-noise ratio of 9. The gas traced by NH _3 exhibits subsonic motions, with an average temperature of 10.4 K. A fit of the radial column density profile derived from the ammonia emission finds a flat inner region of radius ∼1800 au and a central density of ∼6 × 10 ^5 cm ^−3 . Virial and density structure analysis reveals the core is marginally bound ( α _vir = 0.73). The region is entirely consistent with that of a young starless core, hence ruling out CB 17 MMS as an FHSC candidate. Additionally, the core exhibits a velocity gradient aligned with the major axis, showing an arc-like structure in the position–velocity diagram and an off-center region with high velocity dispersion, caused by two distinct velocity peaks. These features could be due to interactions with the nearby outflow, which appears to deflect due to the dense gas near the NH _3 column density peak. We investigate the specific angular momentum profile of the starless core, finding that it aligns closely with previous studies of similar radial profiles in Class 0 sources. This similarity to more evolved objects suggests that motions at 1000 au scales are determined by large-scale dense cloud motions, and may be preserved throughout the early stages of star formation.https://doi.org/10.3847/1538-4357/ac3083Star formationProtostarsBok globulesInterferometryInterstellar medium |
| spellingShingle | Stephanie Spear María José Maureira Héctor G. Arce Jaime E. Pineda Michael Dunham Paola Caselli Dominique Segura-Cox VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate The Astrophysical Journal Star formation Protostars Bok globules Interferometry Interstellar medium |
| title | VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate |
| title_full | VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate |
| title_fullStr | VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate |
| title_full_unstemmed | VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate |
| title_short | VLA and NOEMA Views of Bok Globule CB 17: The Starless Nature of a Proposed First Hydrostatic Core Candidate |
| title_sort | vla and noema views of bok globule cb 17 the starless nature of a proposed first hydrostatic core candidate |
| topic | Star formation Protostars Bok globules Interferometry Interstellar medium |
| url | https://doi.org/10.3847/1538-4357/ac3083 |
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