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Mass segregation

About: Mass segregation is a research topic. Over the lifetime, 1024 publications have been published within this topic receiving 57729 citations.


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TL;DR: In this paper, a 3D map of the Hyades cluster in the stellar and sub-stellar regimes is presented, with a list of members from the most massive stars down to the brown dwarfs.
Abstract: Aims . Our scientific goal is to provide a 3D map of the nearest open cluster to the Sun, the Hyades, combining the recent release of Gaia astrometric data, ground-based parallaxes of sub-stellar member candidates and photometric data from surveys which cover large areas of the cluster.Methods . We combined the second Gaia release with ground-based H -band parallaxes obtained with the infrared camera on the 2 m robotic Liverpool telescope to astrometrically identify stellar and sub-stellar members of the Hyades, the nearest open cluster to the Sun.Results . We find 1764 objects within 70° radius from the cluster centre from the Gaia second data release, whose kinematic properties are consistent with the Hyades. We limit our study to 30 pc from the cluster centre (47.03 ± 0.20 pc) where we identify 710 candidate members, including 85 and 385 in the core and tidal radius, respectively. We determine proper motions and parallaxes of eight candidate brown dwarf members and confirm their membership. Using the 3D positions and a model-based mass-luminosity relation we derive a luminosity and mass function in the 0.04–2.5 M ⊙ range. We confirm evidence for mass segregation in the Hyades and find a dearth of brown dwarfs in the core of the cluster. From the white dwarf members we estimate an age of 640 Myr.Conclusions . We identify a list of members in the Hyades cluster from the most massive stars down to the brown dwarfs. We produce for the first time a 3D map of the Hyades cluster in the stellar and sub-stellar regimes and make available the list of candidate members.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an analysis of the clustering properties of these cores, including the two-point correlation function and Cartwright's Q parameter, and find that in each cluster, the most massive cores tend to be centrally located.
Abstract: The JCMT Gould Belt Legacy Survey obtained SCUBA-2 observations of dense cores within three sub-regions of Orion B: LDN 1622, NGC 2023/2024, and NGC 2068/2071, all of which contain clusters of cores. We present an analysis of the clustering properties of these cores, including the two-point correlation function and Cartwright's Q parameter. We identify individual clusters of dense cores across all three regions using a minimal spanning tree technique, and find that in each cluster, the most massive cores tend to be centrally located. We also apply the independent M-Sigma technique and find a strong correlation between core mass and the local surface density of cores. These two lines of evidence jointly suggest that some amount of mass segregation in clusters has happened already at the dense core stage.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the early development of star clusters in the extreme environments and discuss the restrictions that strong radiative cooling and stellar mass segregation provide on the gas expulsion from dense star-forming clouds.
Abstract: Gas expulsion or gas retention is a central issue in most of the models for multiple stellar populations and light element anti-correlations in globular clusters. The success of the residual matter expulsion or its retention within young stellar clusters has also a fundamental importance in order to understand how star formation proceeds in present-day and ancient star-forming galaxies and if proto-globular clusters with multiple stellar populations are formed in the present epoch. It is usually suggested that either the residual gas is rapidly ejected from star-forming clouds by stellar winds and supernova explosions, or that the enrichment of the residual gas and the formation of the second stellar generation occur so rapidly, that the negative stellar feedback is not significant. Here we continue our study of the early development of star clusters in the extreme environments and discuss the restrictions that strong radiative cooling and stellar mass segregation provide on the gas expulsion from dense star-forming clouds. A large range of physical initial conditions in star-forming clouds which include the star-forming cloud mass, compactness, gas metallicity, star formation efficiency and effects of massive stars segregation are discussed. It is shown that in sufficiently massive and compact clusters hot shocked winds around individual massive stars may cool before merging with their neighbors. This dramatically reduces the negative stellar feedback, prevents the development of the global star cluster wind and expulsion of the residual and the processed matter into the ambient interstellar medium. The critical lines which separate the gas expulsion and the gas retention regimes are obtained.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the authors make use of N$-body simulations to determine the relationship between two observable parameters that are used to quantify mass segregation and energy equipartition in star clusters.
Abstract: We make use of $N$-body simulations to determine the relationship between two observable parameters that are used to quantify mass segregation and energy equipartition in star clusters. Mass segregation can be quantified by measuring how the slope of a cluster's stellar mass function $\alpha$ changes with clustercentric distance r, and then calculating $\delta_\alpha = \frac{d \alpha(r)}{d ln(r/r_m)}$ where $r_m$ is the cluster's half-mass radius. The degree of energy equipartition in a cluster is quantified by $\eta$, which is a measure of how stellar velocity dispersion $\sigma$ depends on stellar mass m via $\sigma(m) \propto m^{-\eta}$. Through a suite of $N$-body star cluster simulations with a range of initial sizes, binary fractions, orbits, black hole retention fractions, and initial mass functions, we present the co-evolution of $\delta_\alpha$ and $\eta$. We find that measurements of the global $\eta$ are strongly affected by the radial dependence of $\sigma$ and mean stellar mass and the relationship between $\eta$ and $\delta_\alpha$ depends mainly on the cluster's initial conditions and the tidal field. Within $r_m$, where these effects are minimized, we find that $\eta$ and $\delta_\alpha$ initially share a linear relationship. However, once the degree of mass segregation increases such that the radial dependence of $\sigma$ and mean stellar mass become a factor within $r_m$, or the cluster undergoes core collapse, the relationship breaks down. We propose a method for determining $\eta$ within $r_m$ from an observational measurement of $\delta_\alpha$. In cases where $\eta$ and $\delta_\alpha$ can be measured independently, this new method offers a way of measuring the cluster's dynamical state.

30 citations

Journal ArticleDOI
TL;DR: In this paper, a 3D map of the Hyades cluster in the stellar and sub-stellar regimes is presented, with a list of members from the most massive stars down to the brown dwarfs.
Abstract: Our scientific goal is to provide a 3D map of the nearest open cluster to the Sun, the Hyades, combining the recent release of Gaia astrometric data, ground-based parallaxes of sub-stellar member candidates and photometric data from surveys which cover large areas of the cluster. We combined the second Gaia release with ground-based H-band parallaxes obtained with the infrared camera on the 2-m robotic Liverpool telescope to astrometrically identify stellar and sub-stellar members of the Hyades, the nearest open cluster to the Sun. We find 1764 objects within 70 degree radius from the cluster center from the Gaia second data release, whose kinematic properties are consistent with the Hyades. We limit our study to 30 pc from the cluster center (47.03+/-0.20 pc) where we identify 710 candidate members, including 85 and 385 in the core and tidal radius, respectively. We determine proper motions and parallaxes of eight candidate brown dwarf members and confirm their membership. Using the 3D positions and a model-based mass-luminosity relation we derive a luminosity and mass function in the 0.04 to 2.5 Msun range. We confirm evidence for mass segregation in the Hyades and find a dearth of brown dwarfs in the core of the cluster. From the white dwarf members we estimate an age of 640$^{+67}_{-49}$ Myr. We identify a list of members in the Hyades cluster from the most massive stars down to the brown dwarfs. We produce for the first time a 3D map of the Hyades cluster in the stellar and sub-stellar regimes and make available the list of candidate members.

30 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202336
202225
202133
202047
201943
201822