Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121

D. S. Shepherd, M. S. Povich, B. A. Whitney, T. P. Robitaille, D. E A Nürnberger, L. Bronfman, Daniel P Stark, R. Indebetouw, M. R. Meade, B. L. Babler

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Abstract

We have observed the central region of the infrared-dark cloud filament associated with IRAS 18507+0121 at millimeter wavelengths in CO(J = 1-0), 13CO(J = 1-0), and C18O(J = 1-0) line emission and with Spitzer at midinfrared wavelengths. Five massive outflows from two cloud cores were discovered. Three outflows are centered on or near an ultracompact (UC) H II region (G34.4+0.23), while the remaining two outflows originate from the millimeter core G34.4+0.23 MM. Modeling of the spectral energy distributions of the mid-infrared sources identified 31 young stellar objects in the filament with a combined stellar mass of ∼ 127 ± 27 M. An additional 22 sources were identified as probable cluster members based on the presence of strong 24 μm emission. The total star formation efficiency in the G34.4 cloud filament is estimated to be ∼7%, while the massive and intermediate-mass star formation efficiency in the entire cloud filament is estimated to be roughly 2%. A comparison of the gravitational binding energy with the outflow kinetic energy suggests that the compact core containing G34.4+0.23 MM is being destroyed by its molecular outflows, whereas the outflows associated with the more massive core surrounding the G34.4 UC H II region are not likely to totally disrupt the cloud. In addition, a qualitative evaluation of the region appears to suggest that stars in this region may have formed in two stages: first lower mass stars formed and then, a few Myr later, the more massive stars began to form.

Original languageEnglish (US)
Pages (from-to)464-482
Number of pages19
JournalAstrophysical Journal
Volume669
Issue number1
DOIs
StatePublished - Nov 1 2007
Externally publishedYes

Fingerprint

census
Infrared Astronomy Satellite
massive stars
star formation
outflow
filaments
H II regions
gravitational binding energy
stars
wavelength
spectral energy distribution
stellar mass
wavelengths
kinetic energy
energy
evaluation
modeling

Keywords

  • H II regions
  • ISM: molecules
  • Stars: formation

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Shepherd, D. S., Povich, M. S., Whitney, B. A., Robitaille, T. P., Nürnberger, D. E. A., Bronfman, L., ... Babler, B. L. (2007). Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121. Astrophysical Journal, 669(1), 464-482. https://doi.org/10.1086/521331

Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121. / Shepherd, D. S.; Povich, M. S.; Whitney, B. A.; Robitaille, T. P.; Nürnberger, D. E A; Bronfman, L.; Stark, Daniel P; Indebetouw, R.; Meade, M. R.; Babler, B. L.

In: Astrophysical Journal, Vol. 669, No. 1, 01.11.2007, p. 464-482.

Research output: Contribution to journalArticle

Shepherd, DS, Povich, MS, Whitney, BA, Robitaille, TP, Nürnberger, DEA, Bronfman, L, Stark, DP, Indebetouw, R, Meade, MR & Babler, BL 2007, 'Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121', Astrophysical Journal, vol. 669, no. 1, pp. 464-482. https://doi.org/10.1086/521331
Shepherd DS, Povich MS, Whitney BA, Robitaille TP, Nürnberger DEA, Bronfman L et al. Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121. Astrophysical Journal. 2007 Nov 1;669(1):464-482. https://doi.org/10.1086/521331
Shepherd, D. S. ; Povich, M. S. ; Whitney, B. A. ; Robitaille, T. P. ; Nürnberger, D. E A ; Bronfman, L. ; Stark, Daniel P ; Indebetouw, R. ; Meade, M. R. ; Babler, B. L. / Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121. In: Astrophysical Journal. 2007 ; Vol. 669, No. 1. pp. 464-482.
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abstract = "We have observed the central region of the infrared-dark cloud filament associated with IRAS 18507+0121 at millimeter wavelengths in CO(J = 1-0), 13CO(J = 1-0), and C18O(J = 1-0) line emission and with Spitzer at midinfrared wavelengths. Five massive outflows from two cloud cores were discovered. Three outflows are centered on or near an ultracompact (UC) H II region (G34.4+0.23), while the remaining two outflows originate from the millimeter core G34.4+0.23 MM. Modeling of the spectral energy distributions of the mid-infrared sources identified 31 young stellar objects in the filament with a combined stellar mass of ∼ 127 ± 27 M⊙. An additional 22 sources were identified as probable cluster members based on the presence of strong 24 μm emission. The total star formation efficiency in the G34.4 cloud filament is estimated to be ∼7{\%}, while the massive and intermediate-mass star formation efficiency in the entire cloud filament is estimated to be roughly 2{\%}. A comparison of the gravitational binding energy with the outflow kinetic energy suggests that the compact core containing G34.4+0.23 MM is being destroyed by its molecular outflows, whereas the outflows associated with the more massive core surrounding the G34.4 UC H II region are not likely to totally disrupt the cloud. In addition, a qualitative evaluation of the region appears to suggest that stars in this region may have formed in two stages: first lower mass stars formed and then, a few Myr later, the more massive stars began to form.",
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AU - Nürnberger, D. E A

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N2 - We have observed the central region of the infrared-dark cloud filament associated with IRAS 18507+0121 at millimeter wavelengths in CO(J = 1-0), 13CO(J = 1-0), and C18O(J = 1-0) line emission and with Spitzer at midinfrared wavelengths. Five massive outflows from two cloud cores were discovered. Three outflows are centered on or near an ultracompact (UC) H II region (G34.4+0.23), while the remaining two outflows originate from the millimeter core G34.4+0.23 MM. Modeling of the spectral energy distributions of the mid-infrared sources identified 31 young stellar objects in the filament with a combined stellar mass of ∼ 127 ± 27 M⊙. An additional 22 sources were identified as probable cluster members based on the presence of strong 24 μm emission. The total star formation efficiency in the G34.4 cloud filament is estimated to be ∼7%, while the massive and intermediate-mass star formation efficiency in the entire cloud filament is estimated to be roughly 2%. A comparison of the gravitational binding energy with the outflow kinetic energy suggests that the compact core containing G34.4+0.23 MM is being destroyed by its molecular outflows, whereas the outflows associated with the more massive core surrounding the G34.4 UC H II region are not likely to totally disrupt the cloud. In addition, a qualitative evaluation of the region appears to suggest that stars in this region may have formed in two stages: first lower mass stars formed and then, a few Myr later, the more massive stars began to form.

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