scholarly journals Investigating the Blue Straggler Stars radial distribution in globular clusters with Monte Carlo simulations

2018 ◽  
Author(s):  
A Sollima ◽  
F R Ferraro
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Radial Distribution ◽  
Globular Clusters ◽  
Blue Straggler

scholarly journals Observations and Simulations of the Blue Straggler Star Radial Distribution: Clues on the Formation Mechanisms

2007 ◽  
Vol 3 (S246) ◽  
pp. 326-330
Author(s):  
Barbara Lanzoni
Keyword(s):  
Mass Transfer ◽  
Monte Carlo ◽  
Radial Distribution ◽  
Globular Clusters ◽  
Formation Mechanisms ◽  
Wide Field ◽  
Field Observations ◽  
Blue Stragglers ◽  
Blue Straggler ◽  
Dynamical Simulations

AbstractBy means of high-resolution and wide-field observations in the UV and optical bands we have derived the radial distribution of the Blue Stragglers Star (BSS) population in a number of galactic globular clusters. Monte-Carlo dynamical simulations have then been used to interpret the observed radial distributions in terms of percentage of collisional and mass-transfer BSS populating each cluster. I will present the main results thus obtained and an overall cluster–to–cluster comparison for the whole sample collected so far, mainly focusing on the clues that such an approach provides about the BSS formation mechanisms.

scholarly journals The blue straggler population of the old open cluster Berkeley 17

2019 ◽  
Vol 624 ◽  
pp. A26 ◽  
Author(s):  
Souradeep Bhattacharya ◽  
Kaushar Vaidya ◽  
W. P. Chen ◽  
Giacomo Beccari
Keyword(s):  
Radial Distribution ◽  
Globular Clusters ◽  
Minimum Spanning Tree ◽  
Open Cluster ◽  
Dynamical Evolution ◽  
Open Clusters ◽  
Blue Straggler ◽  
Magnitude Diagram ◽  
First Time ◽  
Giant Branch Stars

Context. Blue straggler stars (BSSs) are observed in Galactic globular clusters and old open clusters. The radial distribution of BSSs has been used to diagnose the dynamical evolution of globular clusters. For the first time, with a reliable sample of BSSs identified with Gaia DR2, we conduct such an analysis for an open cluster. Aims. We aim to identify members, including BSSs, of the oldest known Galactic open cluster Berkeley 17 with the Gaia DR2 proper motions and parallaxes. We study the radial distribution of the BSS population to understand the dynamical evolution of the cluster. Methods. We selected cluster members to populate the colour magnitude diagram in the Gaia filters. Cluster parameters are derived using the brightest members. The BSSs and giant branch stars are identified, and their radial distributions are compared. The segregation of BSSs is also evaluated with respect to the giant branch stars using the minimum spanning tree (MST) analysis. Results. We determine Berkeley 17 to be at 3138.6−352.9+285.5 pc. We find 23 BSS cluster members, only two of which were previously identified. We find a bimodal radial distribution of BSSs supported by findings from the MST method. Conclusions. The bimodal radial distribution of BSSs in Berkeley 17 indicates that they have just started to sink towards the cluster centre, placing Berkeley 17 with globular clusters of intermediate dynamical age. This is the first such determination for an open cluster.

scholarly journals A Comprehensive Hα Nova Survey of M81

2004 ◽  
Vol 194 ◽  
pp. 240-240
Author(s):  
James D. Neill ◽  
Michael M. Shara ◽  
Elaine Halbedel ◽  
Viktor Malnushenko
Keyword(s):  
Monte Carlo ◽  
Spatial Distribution ◽  
Monte Carlo Simulations ◽  
Lower Limit ◽  
Radial Distribution ◽  
Major Axis ◽  
Stellar Populations ◽  
Light Curves ◽  
Total Light ◽  
Better Than

A spatially complete Hα survey of M81 for novae was conducted continuously over a 5 month interval using the Calypso Telescope at Kitt Peak, AZ. A raw nova rate for M81 gives 23 yr–1 which is a lower limit. Monte Carlo simulations using nova light curves and survey frame limits yield a nova rate of . Using this value and the K-band photometry for M81 from the 2MASS Large Galaxy Atlas of Jarret et al. (2003) gives a luminosity specific nova rate of .The spatial distribution of the novae follows the bulge light much better than the disk or total light according to KS tests of their radial distribution. The asymmetric nova distribution across the major axis line of M81 implies a bulge-to-disk nova ratio of > 9 and supports the idea that novae originate primarily in older stellar populations.

scholarly journals Monte Carlo simulations of multiple populations in globular clusters: constraints on the cooling flow versus accretion scenario using million bodies simulations

2021 ◽  
Vol 502 (2) ◽  
pp. 1974-1989
Author(s):  
A Sollima
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Globular Clusters ◽  
Mixing Time ◽  
Stellar System ◽  
Low Mass Stars ◽  
Multiple Populations ◽  
Cooling Flow ◽  
Radial Segregation ◽  
Set Up

ABSTRACT I simulate the evolution of a stellar system hosting two stellar populations whose initial set-up is defined according to the two main scenarios proposed for the origin of multiple populations in Galactic globular clusters: (i) formation of a second generation from a cooling flow of pristine+polluted gas and (ii) accretion of polluted gas on to the proto-stellar discs of a fraction of low-mass stars. For this purpose, Monte Carlo simulations containing from 105 up to 3 × 106 particles have been run including the effect of stellar evolution, binary interactions, external tidal field, and a detailed modelling of the proto-stellar disc structure. The early accretion of gas on to proto-stellar discs is unable to produce discrete populations and to alter the chemical composition of a significant ($\gt 10{{\ \rm per\ cent}}$) fraction of stars unless a disc lifetime larger (tdisc ∼ 20 Myr) than that predicted by models is assumed. Moreover, in this scenario the mixing time-scale of the two populations is too short to reproduce the observed segregation of the chemically enriched population. On the other hand, simulations run within the cooling flow scenario can evolve after a Hubble time into stellar systems with a first-to-second population mass ratio similar to that observed in globular clusters, provided that an initial filling-factor rh/rJ > 0.15 is adopted. However, in the weak tidal field regime a radial segregation of the second population stronger than what observed in Milky Way globular clusters at large Galactocentric distances is predicted. This discrepancy disappears in simulations following eccentric orbits in a realistic axisymmetric potential.

scholarly journals Monte Carlo Simulations of Star Clusters with Primordial Binaries. Comparison with N-body Simulations and Observations

2007 ◽  
Vol 3 (S246) ◽  
pp. 99-103
Author(s):  
Mirek Giersz ◽  
Douglas C. Heggie
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Globular Clusters ◽  
Large Scale ◽  
Open Cluster ◽  
Star Clusters ◽  
Monte Carlo Code ◽  
Large Scale Simulations ◽  
Free Code

AbstractWe outline the steps needed in to calibrate the Monte Carlo code in order to perform large scale simulations of real globular clusters. We calibrate the results against N-body simulations for N = 2500, 10000 and for the old open cluster M67. The calibration is done by choosing appropriate free code parameters.

scholarly journals Blue Straggler Stars in Galactic Globular Clusters: Tracing the Effect of Dynamics on Stellar Evolution

2007 ◽  
Vol 3 (S246) ◽  
pp. 281-290
Author(s):  
Francesco R. Ferraro ◽  
Barbara Lanzoni
Keyword(s):  
Chemical Composition ◽  
Radial Distribution ◽  
Stellar Evolution ◽  
Globular Clusters ◽  
Blue Stragglers ◽  
Blue Straggler ◽  
Galactic Globular Clusters

AbstractIn this contribution we review the main observational properties of Blue Stragglers Stars (BSS) in galactic GCs. A flower of results on the BSS frequency, radial distribution, and chemical composition are presented and discussed.

scholarly journals Exotic populations in globular clusters: blue stragglers as tracers of the internal dynamical evolution of stellar systems

2014 ◽  
Vol 10 (S312) ◽  
pp. 171-180
Author(s):  
Francesco R. Ferraro
Keyword(s):  
Radial Distribution ◽  
Globular Clusters ◽  
Stellar Population ◽  
Dynamical Evolution ◽  
Stellar Systems ◽  
Internal Dynamics ◽  
Blue Stragglers ◽  
Blue Straggler ◽  
Specific Frequency ◽  
Definition Of

AbstractIn this paper I present an overview of the main observational properties of a special class of exotic objects (the so-called Blue Straggler Stars, BSSs) in Galactic Globular Clusters (GCs). The BSS specific frequency and their radial distribution are discussed in the framework of using this stellar population as probe of GC internal dynamics. In particular, the shape of the BSS radial distribution has been found to be a powerful tracer of the dynamical evolution of stellar systems, thus allowing the definition of an empirical “clock”able to measure the dynamical age of stellar aggregates from pure observational properties.

An empirical clock to measure the dynamical age of star clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 377-383
Author(s):  
Francesco R. Ferraro
Keyword(s):  
Radial Distribution ◽  
Special Class ◽  
Globular Clusters ◽  
Stellar Population ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Stellar Systems ◽  
Central Segregation ◽  
Blue Straggler ◽  
Definition Of

AbstractThe observational properties of a special class of stars (the so-called Blue Straggler stars - BSSs) in Globular Clusters are discussed in the framework of using this stellar population as probe of the dynamical processes occurring in high-density stellar systems. In particular, the shape of the BSS radial distribution and their level of central segregation have been found to be powerful tracers of the level of the dynamical evolution of the hosting cluster, thus allowing the definition of an empirical chronometer able to measure the dynamical age of star clusters.

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