The Luminosity and Mass Function of the Trapezium Cluster: From B Stars to the Deuterium‐burning Limit

Muench, August; Lada, Elizabeth A.; Lada, Charles J.; Alves, J.

doi:10.1086/340554

Cited by 375 publications

(652 citation statements)

References 60 publications

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“…The core contains the Trapezium system consisting of (at least) 6 stars with a total mass of 88.4 M (Hillenbrand 1997). Brown dwarfs have since been detected in the centre of the cluster (Hillenbrand & Carpenter 2000;Luhman et al 2000;Lucas et al 2001;Muench et al 2002), so that the mean mass may decreases to 0.5 M (Scally et al 2005), in good agreement with the canonical IMF.…”

Section: Orion Nebula Clustermentioning

confidence: 69%

Inverse dynamical population synthesis

Marks

Kroupa

2012

A&A

253

302

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Binary populations in young star clusters show multiplicity fractions both lower and up to twice as high as those observed in the Galactic field. We follow the evolution of a population of binary stars in dense and loose star clusters starting with an invariant initial binary population and a formal multiplicity fraction of unity, and demonstrate that these models can explain the observed binary properties in Taurus, ρ Ophiuchus, Chamaeleon, Orion, IC 348, Upper Scorpius A, Praesepe, and the Pleiades. The model needs to consider solely different birth densities for these regions. The evolved theoretical orbital-parameter distributions are highly probable parent distributions for the observed ones. We constrain the birth conditions (stellar mass, M ecl , and half-mass radius, r h ) for the derived progenitors of the star clusters and the overall present-day binary fractions allowed by the present model. The results compare very well with properties of molecular cloud clumps on the verge of star formation. Combining these with previously and independently obtained constraints on the birth densities of globular clusters, we identify a weak stellar mass -half-mass radius correlation for cluster-forming cloud clumps, r h /pc ∝ (M ecl /M ) 0.13 ± 0.04 . The ability of the model to reproduce the binary properties in all the investigated young objects, covering present-day densities from 1−10 stars pc −3 (Taurus) to 2 × 10 4 stars pc −3 (Orion), suggests that environment-dependent dynamical evolution plays an important role in shaping the present-day properties of binary populations in star clusters, and that the initial binary properties may not vary dramatically between different environments.

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Section: Orion Nebula Clustermentioning

confidence: 69%

Inverse dynamical population synthesis

Marks

Kroupa

2012

A&A

253

302

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“…This extensively studied relatively evolved system (see e.g. Hillenbrand 1997;Muench et al 2002) has some obvious similarities to our younger system. Centered on θ 1 C Ori, TC has a diameter of ∼0.3 pc (Hillenbrand 1997) comparable to the separation of the two SDC335 millimetre cores (0.32 pc).…”

Section: The Future Of Sdc335mentioning

confidence: 77%

Tightening the belt: Constraining the mass and evolution in SDC335

Avison

Peretto

Fuller

et al. 2015

A&A

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Aims. Recent ALMA observations identified one of the most massive star-forming cores yet observed in the Milky Way: SDC335-MM1, within the infrared dark cloud SDC335.579-0.292. Along with an accompanying core MM2, SDC335 appears to be in the early stages of its star formation process. We aim to constrain the properties of the stars forming within these two massive millimetre sources. Methods. Observations of SDC335 at 6, 8, 23 and 25 GHz were made with the Australia Telescope Compact Array. We report the results of these continuum measurements, which combined with archival data, allow us to build and analyse the spectral energy distributions (SEDs) of the compact sources in SDC335. Results. Three hyper-compact H regions within SDC335 are identified, two of which are within the MM1 core. For each HCH region, we fit a free-free emission curve to the data, providing the derivation of the sources' emission measure, ionising photon flux, and electron density. Using these physical properties we assign each HCH region a zero-age main sequence (ZAMS) spectral type, finding two protostars with characteristics of spectral type B1.5 and one with a lower limit of B1-B1.5. Ancillary data from infrared to mm wavelength are used to construct free-free component subtracted SEDs for the mm-cores, which allows us to calculate the bolometric luminosities and revise the previous gas mass estimates. Conclusions. The measured luminosities for the two mm-cores are lower than expected from accreting sources displaying characteristics of the ZAMS spectral type assigned to them. The protostars are still actively accreting, suggesting that a mechanism is limiting the accretion luminosity. We present the case for two different mechanisms capable of causing lower than expected accretion luminosity. Finally, using the ZAMS mass values as lower limit constraints, a final stellar population for SDC335 was synthesised finding SDC335 is likely to be in the process of forming a stellar cluster comparable to the Trapezium cluster and NGC 6334 I(N).

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“…The mean stellar mass is aboutm ≈ 0.5 M and the half-mass radius R hm ≈ 1 pc (Hillenbrand & Hartmann 1998). Recent studies of the stellar mass distribution (Hillenbrand & Carpenter 2000;Luhman et al 2000;Muench et al 2002;Slesnick et al 2004) reveal no significant deviation from the generalized IMF of Kroupa (2002),…”

Section: Structure and Dynamics Of The Oncmentioning

confidence: 92%

Stellar interactions in dense and sparse star clusters

Olczak

Pfalzner

Eckart

2010

A&A

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Context. Stellar encounters potentially affect the evolution of the protoplanetary discs in the Orion Nebula Cluster (ONC). However, the role of encounters in other cluster environments is less known. Aims. We investigate the effect of the encounter-induced disc-mass loss in different cluster environments. Methods. Starting from an ONC-like cluster we vary the cluster size and density to determine the correlation of collision time scale and disc-mass loss. We use the nbody6++ code to model the dynamics of these clusters and analyze the disc-mass loss due to encounters. Results. We find that the encounter rate depends strongly on the cluster density but remains rather unaffected by the size of the stellar population. This dependency translates directly into the effect on the encounter-induced disc-mass loss. The essential outcome of the simulations are: i) Even in clusters four times sparser than the ONC the effect of encounters is still apparent. ii) The density of the ONC itself marks a threshold: in less dense and less massive clusters it is the massive stars that dominate the encounter-induced disc-mass loss whereas in denser and more massive clusters the low-mass stars play the major role for the disc mass removal. Conclusions. It seems that in the central regions of young dense star clusters -the common sites of star formation -stellar encounters do affect the evolution of the protoplanetary discs. With higher cluster density low-mass stars become more heavily involved in this process. This finding allows for the extrapolation towards extreme stellar systems: in case of the Arches cluster one would expect stellar encounters to destroy the discs of most of the low-and high-mass stars in several hundred thousand years, whereas intermediate mass stars are able to retain to some extant their discs even under these harsh environmental conditions.

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The Luminosity and Mass Function of the Trapezium Cluster: From B Stars to the Deuterium‐burning Limit

Cited by 375 publications

References 60 publications

Inverse dynamical population synthesis

Inverse dynamical population synthesis

Tightening the belt: Constraining the mass and evolution in SDC335

Stellar interactions in dense and sparse star clusters

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