A photoionization model of the compact HII region G29.96-0.02

Morisset, Charles; Schaerer, D.; Martín-Hernández, N. L.; Peeters, E.; Damour, F; Baluteau, J. P.; Cox, P.; Roelfsema, Pieter

doi:10.1051/0004-6361:20020283

Cited by 40 publications

(65 citation statements)

References 42 publications

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“…Their detection, with integrated intensities similar to that of the underlying continuum, suggests then the presence of an irradiating UV-field in the region. Indeed, all detected transitions are commonly found in regions of intense UV-irradiation where the local ISM is photo-dissociated ([Feii]26 μm, [Siii]34.8 μm plus the three H 2 lines; see Tielens & Hollenbach 1985;and Kaufman et al 1999) or photo-ionized ([Neii]12.8 μm, see Morisset et al 2002), consistent with the spatial distribution of the continuum-subtracted integrated emission for all detected lines. In all panels of Fig.…”

Section: Other Ysos and The Uv-field In The Regionsupporting

confidence: 73%

The pre-ZAMS nature of Mol160/IRAS 23385+6053 confirmed by Spitzer

Molinari

Faustini

Testi

et al. 2008

A&A

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Context. The formation of massive stars goes through phases that remain heavily obscured until the object is well along on the main sequence. The identification of massive YSOs in different evolutionary phases is therefore particularly difficult, and requires a statistical approach with large samples of candidate objects to determine the observational signatures of these different phases. Aims. A mandatory activity in this context is the identification and characterisation of all the phases that a massive forming YSO undergoes. It is of particular interest to verify the observability of the phase in which the object is rapidly accreting while not yet igniting the fusion of hydrogen that marks the arrival on the ZAMS. Methods. One of the candidate prototypical objects for this phase is Mol160/IRAS 23385+6053, which has been the subject of detailed studies that confirmed and strengthened the possibility that this massive YSO may be in a pre-hot core stage. We further investigate this issue by means of Spitzer imaging and spectroscopy in the 5−70 μm range. Results. The dense core of Mol160/IRAS 23385+6053, which up to now had only been detected at submillimeter and millimeter wavelengths, with only upper limits below 20 μm, has been revealed for the first time at 24 and 70 μm by Spitzer. These observations confirm the earlier assumptions that this object is dominant at far-IR wavelengths. The complete 24 μm−3.4 mm continuum cannot be fitted with a standard model of a zero-age main-sequence (ZAMS) star embedded in an envelope. A simple greybody fit yields a mass of 220 M . The luminosity is slightly in excess of 3000 L , which is a factor of 5 less than previous estimates when only IRAS fluxes were available between 20 and 100 μm. The source is under-luminous by the same factor with respect to UCHii regions or hot-cores of similar circumstellar mass, and simple models show that this is compatible with an earlier evolutionary stage. Spectroscopy between 5−40 μm shows that the physical conditions are typical of a photo-dissociated or photo-ionized region. The required UV illumination can be provided by some of the other sources revealed at λ ≤ 24 μm in the same star-forming region, that can be plausibly modeled as moderately embedded intermediate-mass ZAMS stars. Conclusions. Our results strengthen the suggestion that the central core in Mol160/IRAS 23385+6053 is a massive YSO actively accreting from its circumstellar envelope and that it has not yet begun hydrogen fusion.

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Section: Other Ysos and The Uv-field In The Regionsupporting

confidence: 73%

The pre-ZAMS nature of Mol160/IRAS 23385+6053 confirmed by Spitzer

Molinari

Faustini

Testi

et al. 2008

A&A

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“…This is consistent with the [ Ne ii] map of Watarai et al (1998) (Peeters et al 2002a) and of 0.13 in a detailed model of this source (Morisset et al 2002), both after correction for an extinction of A K ¼ 1:6 (Martín- Hernández et al 2002). Likely, this difference is due to extended low surface brightness [Ar iii] emission included in the large SWS aperture but below the detection limit of our SC10 observations.…”

Section: Spatial Variationsupporting

confidence: 92%

The Prominent Dust Emission Feature near 8.9 μm in Four HiiRegions

Peeters¹,

Tielens²,

Boogert³

et al. 2005

ApJ

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We present a mid-infrared study of four H ii regions based on the combination of Infrared Space Observatory (ISO) SWS observations with spatial information from SpectroCam-10 images and long-slit spectra. We report a prominent broad emission feature near 8.9 m. The peak position and width of this feature do not resemble known polycyclic aromatic hydrocarbon ( PAH ) or dust emission features. Its spatial distribution is analyzed for two H ii regions and is clearly distinct from that of the PAH emission features, being more similar to that of the ionized gas and especially to the spatial distribution of the dust continuum at 15 m. Thus, the carrier of this band likely resides within the H ii region. Possible carriers of this feature are highlighted.

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“…Amongst the most detailed studies carried out to date was that of Morisset et al (2002) who derived T eff = 35±3kK for G29.96-0.02 based on CMFGEN and WM-basic models, together with a two component density distribution -a small, high density region (0.1pc, 10…”

Section: Mid-ir Spectroscopymentioning

confidence: 99%

Near and mid infrared observations of ultracompact HII regions

Crowther¹

2005

Proc. IAU

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Abstract. This review discusses near-and mid-infrared observations of Ultracompact (UC) HII regions. The importance of ISO mid-IR fine-structure nebular lines is emphasised, since only a small fraction of UCHII regions are observed directly in the near-IR. The reliability of contemporary atmospheric models for such indirect diagnostics is discussed, whilst a revised spectral type-temperature calibration is presented for Galactic O3 to B3 dwarfs. In particular, fine-structure line derived properties of G29.96-0.02 differ from the direct near-IR spectroscopic result and represents a serious discrepancy which needs to be addressed. Mid-IR MSX and Spitzer imaging permits the identification of those UCHII regions for which far-IR IRAS fluxes are reliable, relevant to the single versus cluster nature of individual sources. High spatial resolution imaging with ground-based 8m telescopes allows more direct tests, as recently applied to G70.29+1.60. Finally, recent Spitzer mid-IR observations of Giant HII regions are briefly discussed.

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A photoionization model of the compact HII region G29.96-0.02

Cited by 40 publications

References 42 publications

The pre-ZAMS nature of Mol160/IRAS 23385+6053 confirmed by Spitzer

The pre-ZAMS nature of Mol160/IRAS 23385+6053 confirmed by Spitzer

The Prominent Dust Emission Feature near 8.9 μm in Four HiiRegions

Near and mid infrared observations of ultracompact HII regions

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