Topic
Mass segregation
About: Mass segregation is a research topic. Over the lifetime, 1024 publications have been published within this topic receiving 57729 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the authors present a comprehensive investigation of main-sequence (MS) binaries in the DRAGON simulations, which are the first one-million particles direct $N$-body simulations of globular clusters.
Abstract: We present a comprehensive investigation of main-sequence (MS) binaries in the DRAGON simulations, which are the first one-million particles direct $N$-body simulations of globular clusters. We analyse the orbital parameters of the binary samples in two of the DRAGON simulations, D1-R7- IMF93 and D2-R7-IMF01, focusing on their secular evolution and correlations up to 12 Gyr. These two models have different initial stellar mass functions: Kroupa 1993 (D1-R7-IMF93) and Kroupa 2001 (D2-R7-IMF01); and different initial mass ratio distributions: random paring (D1-R7-IMF93) and a power-law (D1-R7-IMF93). In general, the mass ratio of a population of binaries increases over time due to stellar evolution, which is less significant in D2-R7-IMF01. In D1-R7-IMF93, primordial binaries with mass ratio $q \approx$ 0.2 are most common, and the frequency linearly declines with increasing $q$ at all times. Dynamical binaries of both models have higher eccentricities and larger semi-major axes than primordial binaries. They are preferentially located in the inner part of the star cluster. Secular evolution of binary orbital parameters does not depend on the initial mass-ratio distribution, but is sensitive to the initial binary distribution of the system. At t = 12 Gyr, the binary fraction decreases radially outwards, and mass segregation is present. A color difference of 0.1 mag in $F330W-F814W$ and 0.2 mag in $NUV-y$ between the core and the outskirts of both clusters is seen, which is a reflection of the binary radial distribution and the mass segregation in the cluster. The complete set of data for primordial and dynamical binary systems at all snapshot intervals is made publicly available.
Journal Article•
TL;DR: In this paper, the results of BV(RI)KC CCD photom- etry down to V = 2 1mag in the region of NGC 6994 were presented.
Abstract: We present the results of BV(RI)KC CCD photom- etry down to V =2 1mag in the region of NGC 6994. To our knowledge, no photometry has previously been reported for this object and we find evidences that it is a poor and sparse old open cluster, with a minimum angular diameter of 9 arcmin, i.e. larger than the 3 arcmin originally assigned to it. We obtain a color excess EB V =0 :07 0:02 mag by means of the BV IC technique. Based on the theoretical isochrones from VandenBerg (1985) that are in better agree- ment with our data, we estimate for this cluster a distance from the Sun of 620 pc (V0 MV =9 0:25 mag) and an age lying within the range o f2-3G yr,adopting solar metallic- ity. Thus, the corresponding cluster's Galactocentric distance is 8.1 kpc and is placed at about 350 pc below the Galactic plane. According to these results, NGC 6994 belongs to the old open cluster population located in the outer disk and at large distances from the Galactic plane, and must have suffered significant in- dividual dynamical evolution, resulting in mass segregation and evaporation of low mass stars.
01 Jan 1988
TL;DR: In this article, low mass X-ray sources observed in many globular clusters are interpreted as compact binaries with degenerate components (e.g., Hertz and Grindlay 1983).
Abstract: Low mass X-ray sources observed in many globular clusters are usually interpreted as compact binaries with degenerate components (e.g., Hertz and Grindlay 1983). Degenerate stars can exist in globular clusters if the IMF contains a sufficiently large number of high mass stars. Since the main-sequence lifetime is a very steep function of stellar mass, most of degenerate stars can be regarded as primordial. If the typical mass of degenerate stars is higher than that of main-sequence stars, mass segregation makes the core crowded with degenerate stars. Tidally captured binaries between degenerates and main-sequence stars can abundantly form as the core density becomes very high.
Posted Content•
TL;DR: In this article, the early dynamics of star clusters, the process of primordial mass segregation and clustering observed in certain young clusters are discussed, and how the dynamics coupled with stellar evolution of a cluster define the radial profile, mass function of and disruption the cluster and compare these parameters with some known clusters.
Abstract: Star clusters are evolving n-body systems. We discuss the early dynamics of star clusters, the process of primordial mass segregation and clustering observed in certain young clusters. We discuss how the dynamics coupled with stellar evolution of a cluster define the radial profile, mass function of and disruption the cluster and compare these parameters with some known clusters. As a member of the Thirty Meter Telescope (TMT), International Science Driven Team (ISDT), I shall use these details to help define the science case, requirements and the expected precision in answering possible questions about the evolution of star clusters in terms of astrometry and high resolution spectroscopy. I shall also report on some of the resolutions made at the recent TMT-Forum held in Mysore, India.
08 Jul 2022
TL;DR: In this paper , the demographics of post-mass-transfer systems (BSSs, white dwarfs and blue lurkers) present in the open clusters and how they are formed were analyzed.
Abstract: Binary systems can evolve into immensely different exotic systems such as blue straggle stars (BSSs), yellow straggler stars, cataclysmic variables, type Ia supernovae depending on their initial mass, the orbital parameters and evolution. The aim of this thesis is to understand the demographics of post-mass-transfer systems (BSSs, white dwarfs and blue lurkers) present in the open clusters and how they are formed. First, we identified the cluster members using Gaia EDR3 data in six open clusters. Two of the clusters, M67 and King2, were studied in detail using UVIT, Gaia, GALEX, 2MASS and other archival photometric data. The comprehensive panchromatic study showed that (i) there is a robust mass-transfer pathway for BSSs, and blue lurkers in M67, (ii) at least 15% of BSSs in King 2 were formed via binary mass transfer. We also created a homogeneous catalogue of open cluster BSSs using Gaia DR2 data. The analysis of 868 BSSs across 208 clusters showed that (i) BSS frequency increases with age, (ii) there is a power-law relation between cluster mass and maximum number of BSSs, (iii) the formation mechanism of BSSs is dominated by binary mass transfer (54-67%) though there exists a 10-16% chance of BSSs forming through more than 2 stellar interactions. This study demonstrates that there exists an extensive variety in the demographics of binary products, and the UV observations are vital for their detection and characterisation.