Unveiling the nature and interaction of the intermediate/high-mass YSOs in IRAS 20343+4129

Palau, Aina; Estalella, R.; Ho, Paul T. P.; Beuther, H.; Beltrán, M. T.

doi:10.1051/0004-6361:20077692

Cited by 32 publications

(61 citation statements)

References 61 publications

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“…That the NH 3 -to-N 2 H + relative abundance in the gas phase is somehow enhanced in quiescent cores was firstly found in the intermediate-/high-mass protocluster IRAS 20293+3952 by Palau et al (2007a), in consistency with observations of lowmass star-forming regions (Hotzel et al 2004;Friesen et al 2010). In the low-mass regime, the NH 3 /N 2 H + abundance ratio was also found to increase towards the centre of low-mass starless cores (e.g.…”

Section: Discussionsupporting

confidence: 80%

“…On the other hand, in the few examples of protoclusters that contain more massive objects, line widths comparable to those measured in I05345 have been found (e.g. Palau et al 2007a;Pillai et al 2011).…”

Section: Non-thermal Contribution To the Velocity Dispersionmentioning

confidence: 62%

“…Tafalla et al 2002) and are therefore excellent tracers of dense gas. Studies in both low-and high-mass star-forming regions (Hotzel et al 2004;Palau et al 2007a) suggest that the abundance ratio of the two species in dense cores is sensitive to evolution during the pre-stellar phase and the very beginning of the protostellar phase, with the ratio NH 3 /N 2 H + decreasing with time. Once CO is considerably desorbed from grain mantles by protostellar feedback (either by outflow passage or by an increase in temperature), N 2 H + is progressively destroyed and the ratio increases again (Busquet et al 2011).…”

Section: Discussionmentioning

confidence: 99%

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Temperature and kinematics of protoclusters with intermediate and high-mass stars: the case of IRAS 05345+3157

Fontani

Caselli

Zhang

et al. 2012

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Context. Improving our understanding of the complex star formation process in clusters requires studies of star-forming clouds to search for dependencies of the physical properties on environmental variables, such as overall density, stellar crowding and feedback from massive (proto-)stars. Aims. We aim to map at small spatial scales the temperature and the velocity field in the protocluster associated with IRAS 05345+3157, which contains both intermediate-/high-mass protostellar candidates and starless condensations, and is thus an excellent location to investigate the role of massive protostars on protocluster evolution. Methods. We observed the ammonia (1, 1) and (2, 2) inversion transitions with the VLA. Ammonia is the best thermometer for dense and cold gas, and the observed transitions have critical densities able to trace the kinematics of the intracluster gaseous medium. Results. The ammonia emission is extended and distributed in two filamentary structures. The starless condensations are colder than the star-forming cores, but the gas temperature across the whole protocluster is higher (by a factor of 1.3−1.5) than that measured typically in both infrared dark clouds and low-mass protoclusters. The non-thermal contribution to the observed line broadening is at least a factor of 2 larger than the expected thermal broadening even in starless condensations, contrary to the close-to-thermal line widths measured in low-mass quiescent dense cores. The NH 3 /N 2 H + abundance ratio is greatly enhanced (a factor of 10) in the pre-stellar core candidates, probably due to freeze-out of most molecular species heavier than He. Conclusions. The more massive and evolved objects likely play a dominant role in the physical properties and kinematics of the protocluster. The high level of turbulence and the fact that the measured core masses are larger than the expected thermal Jeans masses indicate that turbulence likely was an important factor in the initial fragmentation of the parental clump and can provide support against further fragmentation of the cores.

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Section: Discussionsupporting

confidence: 80%

Section: Non-thermal Contribution To the Velocity Dispersionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

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Temperature and kinematics of protoclusters with intermediate and high-mass stars: the case of IRAS 05345+3157

Fontani

Caselli

Zhang

et al. 2012

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“…(a) Bootstraped flux is in Jy. (b) The detailed description for NVSS data can be found in Condon et al (1998). interferometer observations performed by Palau et al (2007b) detected several prestellar candidates compressed by the expanding cavity driven by a massive young stellar objects (YSO) in IRAS 20343+4129, and the line widths are clearly non-thermal, unlike what is observed in clustered low-mass prestellar cores.…”

Section: Introductionmentioning

confidence: 99%

Ongoing star formation in the protocluster IRAS 22134+5834

Wang

Audard

Fontani

et al. 2016

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Aims. Massive stars form in clusters, and their influence on nearby starless cores is still poorly understood. The protocluster associated with IRAS 22134+5834 represents an excellent laboratory for studying the influence of massive YSOs on nearby starless cores and the possible implications in the clustered star formation process. Methods. IRAS 22134+5834 was observed in the cm range with (E)VLA, 3 mm with CARMA, 2 mm with PdBI, and 1.3 mm with SMA, to study both the continuum emission and the molecular lines that trace different physical conditions of the gas. Results. The multiwavelength centimeter continuum observations revealed two radio sources within the cluster, VLA1 and VLA2. VLA1 is considered to be an optically thin UCH region with a size of 0.01 pc that sits at the edge of the near-infrared (NIR) cluster. The flux of ionizing photons of the VLA1 corresponds to a B1 ZAMS star. VLA2 is associated with an infrared point source and has a negative spectral index. We resolved six millimeter continuum cores at 2 mm, MM2 is associated with the UCH region VLA1, and other dense cores are distributed around the UCH region. Two high-mass starless clumps (HMSC), HMSC-E (east) and HMSC-W (west), are detected around the NIR cluster with N 2 H + (1-0) and NH 3 emission, and they show different physical and chemical properties. Two N 2 D + cores are detected on an NH 3 filament close to the UCH region with a projected separation of ∼8000 AU at the assumed distance of 2.6 kpc. The kinematic properties of the molecular line emission confirm that the UCH region is expanding and that the molecular cloud around the NIR cluster is also expanding. Conclusions. Our multiwavelength study has revealed different generations of star formation in IRAS 22134+5834. The formed intermediate-to-massive stars show a strong impact on nearby starless clumps. We propose that the starless clumps and HMPOs formed at the edge of the cluster while the stellar wind from the UCH region and the NIR cluster drives the large scale bubble.

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“…Red (dashed) contours: emission in the velocity range from +15 km s −1 to most positive values with respect to the systemic velocity. Levels start at 9%, increasing in steps of 15% of the peak intensity, to calculate the outflow CO column density, N(CO), from the transition J → J − 1, and the outflow mass, M out , are given in Palau et al (2007b). We adopted an opacity in the line wings of Table 6.…”

Section: Co Kinematics: Moments and Pv-plotsmentioning

confidence: 99%

Three intermediate-mass young stellar objects with different properties emerging from the same natal cloud in IRAS 00117+6412

Palau¹,

Sánchez-Monge

Busquet

et al. 2010

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Aims. Our main aim is to study the influence of the initial conditions of a cloud in the intermediate/high-mass star formation process. Methods. We observed with the VLA, PdBI, and SMA the centimeter and millimeter continuum, N 2 H + (1-0), and CO (2-1) emission associated with a dusty cloud harboring a nascent cluster with intermediate-mass protostars.Results. At centimeter wavelengths we found a strong source, tracing a UCH ii region, at the eastern edge of the dusty cloud, with a shell-like structure, and with the near-infrared counterpart falling in the center of the shell. This is presumably the most massive source of the forming cluster. About 15 to the west of the UCH ii region and well embedded in the dusty cloud, we detected a strong millimeter source, MM1, associated with centimeter and near-infrared emission. MM1 seems to be driving a prominent high-velocity CO bipolar outflow elongated in the northeast-southwest direction, and is embedded in a ridge of dense gas traced by N 2 H + , elongated roughly in the same direction as the outflow. We estimated that MM1 is an intermediate-mass source in the Class 0/I phase. About 15 to the south of MM1, and still more deeply embedded in the dusty cloud, we detected a compact millimeter source, MM2, with neither centimeter nor near-infrared emission, but with water maser emission. MM2 is associated with a clump of N 2 H + , whose kinematics reveal a clear velocity gradient and additionally we found signposts of infall motions. MM2, being deeply embedded within the dusty cloud, with an associated water maser but no hints of CO outflow emission, is an intriguing object, presumably of intermediate mass.Conclusions. The UCH ii region is found at the border of a dusty cloud which is currently undergoing active star formation. Two intermediate-mass protostars in the dusty cloud seem to have formed after the UCH ii region and have different properties related to the outflow phenomenon. Thus, a single cloud with similar dust emission and similar dense gas column densities seems to be forming objects with different properties, suggesting that the initial conditions in the cloud are not determining all the star formation process.

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Unveiling the nature and interaction of the intermediate/high-mass YSOs in IRAS 20343+4129

Cited by 32 publications

References 61 publications

Temperature and kinematics of protoclusters with intermediate and high-mass stars: the case of IRAS 05345+3157

Temperature and kinematics of protoclusters with intermediate and high-mass stars: the case of IRAS 05345+3157

Ongoing star formation in the protocluster IRAS 22134+5834

Three intermediate-mass young stellar objects with different properties emerging from the same natal cloud in IRAS 00117+6412

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