Physical conditions in star-forming regions around S235

Kirsanova, M. S.; Wiebe, D. S.; Соболев, А. М.; Henkel, C.; Цивилев, А. П.

doi:10.1093/mnras/stt1991

Cited by 34 publications

(104 citation statements)

References 32 publications

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“…This value is typical in star-forming regions (Cappa et al 2008;Cichowolski et al 2009;Vasquez et al 2010) and consistent with the gas temperature in the nearby star-forming region S235 (Kirsanova et al 2014) and S233-IR (Schreyer et al 1996).…”

Section: Physical Parameters Of Dustsupporting

confidence: 78%

“…The flux of the IRAS source increases with wavelength (up to 414 Jy at 100 µm) and the colours of the IRAS source correspond to those of a YSO in the colour-colour diagram given by Straižys & Laugalys (2007). The dust temperature of the infrared source, T d = 30.8 K is in good agreement with the gas temperature of star forming clumps in the nearby star-forming region S235 (Kirsanova et al 2014). The gas mass of the IRAS source is found to be 70 M⊙.…”

supporting

confidence: 71%

“…Following Kirsanova et al (2014) we consider the S233 H II region within the framework of the theoretical one-dimensional model described in Whitworth et al (1994). The model allows an estimate of the main characteristics of the 'collect-and-collapse' process: starting time of the dense shell fragmentation (t frag ), the radius of the shell (R frag ) at this moment and the mass of the fragments (M frag ).…”

Section: A Scenario For Star Formation In the S233 Regionmentioning

confidence: 99%

“…We adopt the value of 0.67 pc as a representative radius of the S233 H II region. We adopt 25 K as a typical temperature in the S231-235 complex according to measurements of Kirsanova et al (2014); Schreyer et al (1996). Note that the parameter estimates do not depend critically on the adopted temperature.…”

Section: A Scenario For Star Formation In the S233 Regionmentioning

confidence: 99%

“…We cannot estimate the gas density in the S233 region from our data alone. However, the nearby S235 H II region exhibits an average gas density of ≈ 500 cm −3 only (see Table 1 in Kirsanova et al (2014)). Thus, the value of 4·10 4 cm −3 is probably too high for the average gas density in the S233 H II region.…”

Section: A Scenario For Star Formation In the S233 Regionmentioning

confidence: 99%

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Star formation in the S233 region

Ladeyschikov¹,

Соболев²,

Parfenov³

et al. 2015

Mon. Not. R. Astron. Soc.

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The main objective of this paper is to study the possibility of triggered star formation on the border of the H II region S233, which is formed by a B-star. Using high-resolution spectra we determine the spectral class of the ionizing star as B0.5 V and the radial velocity of the star to be −17.5 ± 1.4 km s −1 . This value is consistent with the velocity of gas in a wide field across the S233 region, suggesting that the ionizing star was formed from a parent cloud belonging to the S233 region. By studying spatial-kinematic structure of the molecular cloud in the S233 region, we detected an isolated clump of gas producing CO emission red-shifted relative to the parent cloud. In the UKIDSS and WISE images, the clump of gas coincides with the infrared source containing a compact object and bright-rimmed structure. The bright-rimmed structure is perpendicular to the direction of the ionizing star. The compact source coincides in position with IRAS source 05351+3549. All these features indicate a possibility of triggering formation of a next-generation star in the S233 region. Within the framework of a theoretical one-dimensional model we conclude that the 'collect-and-collapse' process is not likely to take place in the S233 region. The presence of the bright-rimmed structure and the compact infrared source suggest that the 'collapse of the pre-existing clump' process is taking place.

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Section: Physical Parameters Of Dustsupporting

confidence: 78%

supporting

confidence: 71%

Section: A Scenario For Star Formation In the S233 Regionmentioning

confidence: 99%

Section: A Scenario For Star Formation In the S233 Regionmentioning

confidence: 99%

Section: A Scenario For Star Formation In the S233 Regionmentioning

confidence: 99%

See 3 more Smart Citations

Star formation in the S233 region

Ladeyschikov¹,

Соболев²,

Parfenov³

et al. 2015

Mon. Not. R. Astron. Soc.

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Herschel/HIFI observations of the circumstellar ammonia lines in IRC+10216

Schmidt

Szczerba

et al. 2016

A&A

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Context-A discrepancy exists between the abundance of ammonia (NH 3 ) derived previously for the circumstellar envelope (CSE) of IRC+10216 from far-IR submillimeter rotational lines and that inferred from radio inversion or mid-infrared (MIR) absorption transitions.Aims-To address the discrepancy described above, new high-resolution far-infrared (FIR) observations of both ortho-and para-NH 3 transitions toward IRC+10216 were obtained with Herschel, with the goal of determining the ammonia abundance and constraining the distribution of NH 3 in the envelope of IRC+10216.Methods-We used the Heterodyne Instrument for the Far Infrared (HIFI) on board Herschel to observe all rotational transitions up to the J = 3 level (three ortho-and six para-NH 3 lines). We Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts compared with the new HIFI data, the radio inversion transitions, and the MIR absorption lines in the ν 2 band taken from the literature.Results-We found that NIR pumping is of key importance for understanding the excitation of rotational levels of NH 3 . The derived NH 3 abundances relative to molecular hydrogen were (2.8 ± 0.5) × 10 −8 for ortho-NH 3 and for para-NH 3 , consistent with an ortho/para ratio of 1. These values are in a rough agreement with abundances derived from the inversion transitions, as well as with the total abundance of NH 3 inferred from the MIR absorption lines. To explain the observed rotational transitions, ammonia must be formed near to the central star at a radius close to the end of the wind acceleration region, but no larger than about 20 stellar radii (1σ confidence level).

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APEX CO observations towards the photodissociation region of RCW 120

Figueira

Zavagno

Bronfman

et al. 2020

A&A

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Context. The edges of ionized (H II) regions are important sites for the formation of (high-mass) stars. Indeed, at least 30% of the Galactic high-mass-star formation is observed there. The radiative and compressive impact of the H II region could induce star formation at the border following different mechanisms such as the collect and collapse or the radiation-driven implosion (RDI) models and change their properties. Aims. We aim to study the properties of two zones located in the photo dissociation region (PDR) of the Galactic H II region RCW 120 and discuss them as a function of the physical conditions and young star contents found in both clumps. Methods. Using the APEX telescope, we mapped two regions of size 1.5′ × 1.5′ toward the most massive clump of RCW 120 hosting young massive sources and toward a clump showing a protrusion inside the H II region and hosting more evolved low-mass sources. The 12CO (J = 3−2), 13CO (J = 3−2) and C18O (J = 3−2) lines observed, together with Herschel data, are used to derive the properties and dynamics of these clumps. We discuss their relation with the hosted star formation. Results. Assuming local thermodynamic equilibrium, the increase of velocity dispersion and Tex are found toward the center of the maps, where star-formation is observed with Herschel. Furthermore, both regions show supersonic Mach numbers (7 and 17 in average). No substantial information has been gathered about the impact of far ultraviolet radiation on C18O photodissociation at the edges of RCW 120. The fragmentation time needed for CC to be at work is equivalent to the dynamical age of RCW 120 and the properties of region B are in agreement with bright-rimmed clouds. Conclusions. Although conclusions from this fragmentation model should be taken with caution, it strengthens the fact that, together with evidence of compression, CC might be at work at the edges of RCW 120. Additionally, the clump located at the eastern part of the PDR is a good candidate pre-existing clump where star-formation may be induced by the RDI mechanism.

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Physical conditions in star-forming regions around S235

Cited by 34 publications

References 32 publications

Star formation in the S233 region

Star formation in the S233 region

Herschel/HIFI observations of the circumstellar ammonia lines in IRC+10216

APEX CO observations towards the photodissociation region of RCW 120

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