On the nature of outflows in intermediate-mass protostars: a case study of IRAS 20050+2720

Beltrán, M. T.; Estalella, R.; Girart, J. M.; Ho, Paul T. P.; Anglada, Guillem

doi:10.1051/0004-6361:20078045

Cited by 28 publications

(37 citation statements)

References 72 publications

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“…-Mid-J CO line luminosities adhere to the correlation between total luminosity and line luminosity identified by San Jose-Garcia et al (2013) for low-and high-J CO. -There is no corroboration of the result presented in Beltrán et al (2008) that proposed an apparent enhancement in outflow force for fragmented intermediate-mass sources.…”

Section: Discussioncontrasting

confidence: 53%

Outflow forces in intermediate-mass star formation

Kempen

Hogerheijde

Dishoeck

et al. 2016

A&A

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Context. Protostars of intermediate-mass provide a bridge between theories of low-and high-mass star formation. Molecular outflows emerging from such sources can be used to determine the influence of fragmentation and multiplicity on protostellar evolution through the apparent correlation of outflow forces of intermediate-mass protostars with the total luminosity instead of the individual luminosity. Aims. The aim of this paper is to derive outflow forces from outflows of six intermediate-mass protostellar regions and validate the apparent correlation between total luminosity and outflow force seen in earlier work, as well as remove uncertainties caused by different methodologies. Methods. By comparing CO 6-5 observations obtained with APEX with non-LTE radiative transfer model predictions, the optical depths, temperatures and densities of the gas of the molecular outflows are derived. Outflow forces, dynamical timescales, and kinetic luminosities are subsequently calculated. Results. Outflow parameters, including the forces, were derived for all sources. Temperatures in excess of 50 K were found for all flows, in line with recent low-mass results. However, comparison with other studies could not corroborate conclusions from earlier work on intermediate-mass protostars which hypothesized that fragmentation enhances outflow forces in clustered intermediate-mass star formation. Any enhancement in comparison with the classical relation between outflow force and luminosity can be attributed to the use of a higher excitation line and improvement in methods. They are in line with results from low-mass protostars using similar techniques. Conclusions. The role of fragmentation on outflows is an important ingredient to understand clustered star formation and the link between low-and high-mass star formation. However, detailed information on spatial scales of a few 100 AU, covering all individual members is needed to make the necessary progress.

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Section: Discussioncontrasting

confidence: 53%

Outflow forces in intermediate-mass star formation

Kempen

Hogerheijde

Dishoeck

et al. 2016

A&A

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“…Although the values we obtain are too low for a region like W3 IRS5 with a total luminosity of ∼10 5 L and are more typical in regions with lower luminosity (see e.g. Ridge & Moore 2001;Gibb et al 2007;Palau et al 2007;Beltrán et al 2008), we have to keep in mind that aside from the caveats mentioned above, we are tracing smaller scales opposed to largescale outflow.…”

Section: Outflowsmentioning

confidence: 99%

Millimeter interferometry of W3 IRS5: a trapezium in the making

Rodón¹,

Beuther²,

Megeath

et al. 2008

A&A

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Context. Although most young massive stars appear to be part of multiple systems, it is poorly understood how this multiplicity influences the formation of massive stars. The high-mass star-forming region W3 IRS5 is a prime example of a young massive cluster where the cluster center is resolved into multiple subsources at cm and infrared wavelengths, a potential proto-Trapezium system. Aims. We investigate the protostellar content in the 1.4 mm continuum down to subarcsecond scales and study the compact outflow components, also tracing the outflows back to their driving sources via the shocktracing SiO and SO 2 emission. Methods. The region W3 IRS5 was mapped with the PdBI at 1.4 mm and 3.4 mm in the AB configurations, tuning the receivers to observe the molecular transitions SO 2 (22 2,20 -22 1,21 ), SO 2 (8 3,5 -9 2,8 ), SiO (2-1), and SiO (5-4).Results. In the continuum we detect five sources, one of them for the first time, while counterparts were detected in the NIR, MIR or at radio wavelengths for the remaining four sources. Three of the detected sources are within the inner 2100 AU, where the protostellar number density exceeds 10 6 protostars pc −3 assuming spherical symmetry. Lower limits for the circumstellar masses of the detected sources were calculated, ranging from ∼0.3 to ∼40 M although they were strongly affected by the spatial filtering of the interferometer, losing up to ∼90% of the single-dish flux. However, the projected separations of the sources ranging between ∼750 and ∼4700 AU indicate a multiple, Trapezium-like system. We disentangled the compact outflow component of W3 IRS5, detecting five molecular outflows in SiO, two of them nearly in the line of sight direction, which allowed us to see the collapsing protostars in the NIR through the cavities carved by the outflows. The SO 2 velocity structure indicates a rotating, bound system, and we find tentative signatures of converging flows as predicted by the gravoturbulent star formation and converging flow theories. Conclusions. The obtained data strongly indicate that the clustered environment has a major influence on the formation of high-mass stars; however, our data do not clearly allow us to distinguish whether the ongoing star-forming process follows a monolithic collapse or a competitive accretion mechanism.

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“…1 (see Sect. 4.2) does offer a handle on the scale height H. We applied this estimate for the compiled sample making the assumption that a line width of ∼2 km s −1 is typical (e.g., Beltrán et al, 2006bBeltrán et al, , 2008Fuente et al, 2009). We find that the hydrostatic scale height is in most cases >20-30% of the disk radius but can be as high as 60%.…”

Section: Disks In Embedded Im Protostarsmentioning

confidence: 99%

Accretion disks in luminous young stellar objects

Beltrán

Wit

2016

Astron Astrophys Rev

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191

189

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An observational review is provided of the properties of accretion disks around young stars. It concerns the primordial disks of intermediate-and high-mass young stellar objects in embedded and optically revealed phases. The properties were derived from spatially resolved observations and therefore predominantly obtained with interferometric means, either in the radio/(sub)millimeter or in the optical/infrared wavelength regions. We make summaries and comparisons of the physical properties, kinematics, and dynamics of these circumstellar structures and delineate trends where possible. Amongst others, we report on a quadratic trend of mass accretion rates with mass from T Tauri stars to the highest mass young stellar objects and on the systematic difference in mass infall and accretion rates.

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On the nature of outflows in intermediate-mass protostars: a case study of IRAS 20050+2720

Cited by 28 publications

References 72 publications

Outflow forces in intermediate-mass star formation

Outflow forces in intermediate-mass star formation

Millimeter interferometry of W3 IRS5: a trapezium in the making

Accretion disks in luminous young stellar objects

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