scholarly journals Defining the Binary Star Population in the Young Open Cluster M35 (NGC 2168)

2007 ◽  
Vol 3 (S246) ◽  
pp. 105-106
Author(s):  
Ella K. Braden ◽  
Robert D. Mathieu ◽  
Sören Meibom
Keyword(s):  
Binary Systems ◽  
Initial Conditions ◽  
Binary Star ◽  
Open Cluster ◽  
Open Clusters ◽  
Spatial Period ◽  
Large Sample Size ◽  
Long Baseline ◽  
Dynamical Simulations ◽  
Young Open Cluster

AbstractWe present current results from the ongoing WIYN Open Cluster Study radial-velocity survey for 1410 stars in the young (150 Myr) open cluster M35 (NGC 2168) and establish a benchmark for initial conditions in young open clusters. We find for periods ≲ 1000 days a minimum binary frequency of 0.36 – 0.51. We also analyze the spatial, period and eccentricity distributions of the binary systems and find that the period and eccentricity distributions are well approximated by scaled field distributions from Duquennoy & Mayor (1991). With our large sample size and long baseline, we have a unique understanding of the binary population in this young cluster, making it ideal for defining initial conditions for dynamical simulations.

scholarly journals Open Clusters: Open Windows on Stellar Dynamics

2007 ◽  
Vol 3 (S246) ◽  
pp. 79-88
Author(s):  
Robert D. Mathieu
Keyword(s):  
Open Cluster ◽  
Stellar Dynamics ◽  
Open Clusters ◽  
Orbital Eccentricity ◽  
Empirical Results ◽  
Blue Stragglers ◽  
Tidal Interactions ◽  
Dynamical Simulations ◽  
Young Open Cluster ◽  
Solar Type

AbstractThe extensive stellar radial-velocity surveys of the WIYN Open Cluster Study now allow comprehensive studies of the solar-type hard-binary populations in open clusters as a function of age. We first describe an empirical “initial” hard-binary population as derived from the young open cluster NGC 2168 (M35). Given the limited analyses so far, the cluster binary population is indistinguishable from that of the field. We then compare the hard-binary population in the old open cluster NGC 188 to the binary population in the sophisticated N-body simulations of the old cluster M67 by Hurley et al. The binary populations in the cluster and the simulation show significant differences in binary frequency and fraction of circularized binaries, while otherwise showing similar orbital eccentricity distributions. Since the simulations were designed to match the encounter products in M67, such as blue stragglers, the large reduction in binary fraction indicated by the empirical results likely will also require changes in the simulation physics producing blue stragglers and other anomalous stars arising from stellar dynamics. We present three case studies of stars in open clusters which very likely are products of dynamical encounters between binaries and either single stars or other binaries: the M67 blue straggler S1082, the M67 sub-subgiant S1113, and the horizontal branch star 6819-3002 in the intermediate-age open cluster NGC 6819. Finally, we remind the reader of recent empirical results on the rates of tidal interactions, using tidal circularization periods in open clusters. Every indication is that current theories underestimate the effectiveness of tidal circularization, a result that need to be incorporated into dynamical simulations of dense stellar systems.

Variable Star Identification in the BATC Field of M67

2005 ◽  
Vol 277-279 ◽  
pp. 869-875
Author(s):  
Hwihyun Kim ◽  
Yong Ik Byun
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Variable Star ◽  
Open Cluster ◽  
Open Clusters ◽  
Eclipsing Binaries ◽  
Photometric Variability ◽  
Phase Dispersion ◽  
Star Identification

We present the result of photometric variability investigation for stars in the field of M67. The old open cluster M67, one of the most studied open clusters, shows the sign of significant main-sequence binary population in its color-magnitude diagrams. Identification of eclipsing binaries and follow-up studies will enable us to study the nature of binary population in most direct manner. We used approximately 350 images from the BATC (Beijing-Arizona-Taipei-Connecticut) data archive to examine variability within one square degree field centered on M67. A total of 18 stars were classified to be real variables. Our new discoveries include seven eclipsing binary systems of which two are likely to be W UMa systems. All of these variables were found using the phase dispersion minimization (PDM) method developed by Shin and Byun[11].

scholarly journals Discovery of Four β Cephei Stars in Eclipsing Systems

2006 ◽  
Vol 2 (S240) ◽  
pp. 456-458
Author(s):  
Andrzej Pigulski ◽  
Grzegorz Pojmański
Keyword(s):  
Binary Systems ◽  
Open Cluster ◽  
Eclipsing Binary ◽  
Pulsating Stars ◽  
Two Systems ◽  
Young Open Cluster

AbstractUsing the ASAS-3 photometry, we find the components of four eclipsing binary systems — V916 Cen, HD 101838, V4386 Sgr and HD 168050 — to be β Cephei-type pulsators. The first two systems are members of the young open cluster Stock 14. The pulsating stars are presumably the primary, more massive components in all these systems. The components are detached and for at least two systems, V916 Cen and HD 168050, we may suspect that they will appear to be double-lined spectroscopic ones. In consequence, these stars become very attractive targets for studying pulsations in β Cephei stars by means of asteroseismology.

scholarly journals Eclipsing Binaries in Open Clusters

2006 ◽  
Vol 2 (S240) ◽  
pp. 619-621
Author(s):  
John Southworth
Keyword(s):  
Chemical Composition ◽  
Observational Data ◽  
Open Cluster ◽  
Type Systems ◽  
Open Clusters ◽  
Eclipsing Binaries ◽  
Young Open Cluster ◽  
Stellar Models ◽  
Additional Constraints ◽  
Absolute Parameters

AbstractDetached eclipsing binaries are very useful objects for calibrating theoretical stellar models and checking their predictions. Detached eclipsing binaries in open clusters are particularly important because of the additional constraints on their age and chemical composition from their membership of the cluster. I compile a list containing absolute parameters of well-studied eclipsing binaries in open clusters, and present new observational data on the B-type systems V1481 Cyg and V2263 Cyg which are members of the young open cluster NGC 7128.

scholarly journals N-body Models of Open Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 89-98
Author(s):  
Jarrod R. Hurley
Keyword(s):  
Initial Conditions ◽  
Open Cluster ◽  
Open Clusters ◽  
Cluster Evolution ◽  
Near Future

AbstractN-body simulations of open cluster evolution with primordial binaries are reviewed. In particular, recent results arising from models with initialNin the range of 20000–100000 bodies are compared to earlier idealized models withN~ 2000. Efforts to model real clusters are discussed, including how limitations of the models such as simplified initial conditions will be addressed in the near future.

scholarly journals Variable stars in the field of the young open cluster Roslund 2

2013 ◽  
Vol 9 (S301) ◽  
pp. 495-496
Author(s):  
P. Sowicka ◽  
G. Handler ◽  
R. Taubner ◽  
M. Brunner ◽  
V.-M. Passegger ◽  
...  
Keyword(s):  
Open Cluster ◽  
Variable Stars ◽  
Interstellar Cloud ◽  
Star Cluster ◽  
Open Clusters ◽  
Light Curves ◽  
Ccd Photometry ◽  
Open Star ◽  
Young Open Cluster ◽  
Open Star Cluster

AbstractThe study of variable stars in open clusters via asteroseismology is a powerful tool for the study of stellar evolution and stars in general. That is because stars in clusters can be assumed to originate from the same interstellar cloud, so they share similar properties such as age and overall metallicity. We performed a search for variable stars in the field of the young open star cluster Roslund 2, with photoelectric and CCD photometry acquired at two different telescopes. Within the resulting light curves we have found 12 variable stars. Our measurements confirm three previously known variables.

scholarly journals Primordial mass segregation of star clusters with primordial binaries

2020 ◽  
Vol 638 ◽  
pp. A155
Author(s):  
Václav Pavlík
Keyword(s):  
Binary Systems ◽  
Initial Conditions ◽  
Binary Star ◽  
Relaxation Times ◽  
Star Clusters ◽  
Young Star ◽  
Initial Mass Function ◽  
Orion Nebula ◽  
Link Type ◽  
Mass Segregation

Context. Observations of young star-forming regions suggest that star clusters are born completely mass segregated. These initial conditions are, however, gradually lost as the star cluster evolves dynamically. For star clusters with single stars only and a canonical initial mass function, it has been suggested that traces of these initial conditions vanish at a time τv between 3 and 3.5 trh (initial half-mass relaxation times). Aims. Since a significant fraction of stars are observed in binary systems and it is widely accepted that most stars are born in binary systems, we aim to investigate what role a primordial binary population (even up to 100% binaries) plays in the loss of primordial mass segregation of young star clusters. Methods. We used numerical N-body models similar in size to the Orion Nebula Cluster (ONC) – a representative of young open clusters – integrated over several relaxation times to draw conclusions on the evolution of its mass segregation. We also compared our models to the observed ONC. Results. We found that τv depends on the binary star fraction and the distribution of initial binary parameters that include a semi-major axis, eccentricity, and mass ratio. For instance, in the models with 50% binaries, we find τv = (2.7 ± 0.8) trh, while for 100% binary fraction, we find a lower value τv = (2.1 ± 0.6) trh. We also conclude that the initially completely mass segregated clusters, even with binaries, are more compatible with the present-day ONC than the non-segregated ones.

scholarly journals Stellar population astrophysics (SPA) with the TNG

2020 ◽  
Vol 633 ◽  
pp. A38 ◽  
Author(s):  
V. D’Orazi ◽  
E. Oliva ◽  
A. Bragaglia ◽  
A. Frasca ◽  
N. Sanna ◽  
...  
Keyword(s):  
Open Cluster ◽  
Solar Spectrum ◽  
Chemical Properties ◽  
Mean Value ◽  
Open Clusters ◽  
Hyades Cluster ◽  
Chemical Content ◽  
Young Open Cluster ◽  
Solar Type ◽  
Young Counterpart

Context. Open clusters exquisitely track the Galactic disc chemical properties and its time evolution; a substantial number of studies and large spectroscopic surveys focus mostly on the chemical content of relatively old clusters (age ≳ 1 Gyr). Interestingly, the less studied young counterpart populating the solar surrounding has been found to be solar (at most), with a notable surprising lack of young metal-rich objects. While there is wide consensus about the moderately above-solar composition of the Hyades cluster, the metallicity of Praesepe is still controversial. Recent studies suggest that these two clusters share identical chemical composition and age, but this conclusion is disputed. Aims. With the aim of reassessing the metallicity of Praesepe, and its difference (if any) with the Hyades cluster, we present in this paper a spectroscopic investigation of ten solar-type dwarf members. Methods. We exploited GIARPS at the TNG to acquire high-resolution, high-quality optical and near-IR spectra and derived stellar parameters, metallicity ([Fe/H]), light elements, α- and iron-peak elements, by using a strictly differential (line-by-line) approach. We also analysed in the very same way the solar spectrum and the Hyades solar analogue HD 28099. Results. Our findings suggest that Praesepe is more metal-rich than the Hyades, at the level of Δ[Fe/H] = +0.05 ± 0.01 dex, with a mean value of [Fe/H] = +0.21 ± 0.01 dex. All the other elements scale with iron, as expected. This result seems to reject the hypothesis of a common origin for these two open clusters. Most importantly, Praesepe is currently the most metal-rich, young open cluster living in the solar neighbourhood.

scholarly journals Orbital stability of Earth-type planets in stellar binary systems

2009 ◽  
Vol 5 (H15) ◽  
pp. 691-692
Author(s):  
Jason Eberle ◽  
Manfred Cuntz ◽  
Zdzislaw E. Musielak
Keyword(s):  
Numerical Simulation ◽  
Binary Systems ◽  
Initial Conditions ◽  
Binary Star ◽  
Orbital Stability ◽  
Considerable Effect ◽  
Planetary Orbit ◽  
The Sun ◽  
The Stability ◽  
The Universe

AbstractAn important factor in estimating the likelihood of life elsewhere in the Universe is determining the stability of a planet's orbit. A significant fraction of stars like the Sun occur in binary systems which often has a considerable effect on the stability of any planets in such a system. In an effort to determine the stability of planets in binary star systems, we conducted a numerical simulation survey of several mass ratios and initial conditions. We then estimated the stability of the planetary orbit using a method that utilizes the hodograph to determine the effective eccentricity of the planetary orbit. We found that this method can serve as an orbital stability criterion for the planet.

scholarly journals Toward a VLBI resolution of the Pleiades distance controversy

2012 ◽  
Vol 8 (S289) ◽  
pp. 60-65
Author(s):  
Carl Melis ◽  
M. J. Reid ◽  
A. J. Mioduszewski ◽  
J. R. Stauffer ◽  
G. C. Bower
Keyword(s):  
Main Sequence ◽  
Very Long Baseline Interferometry ◽  
Open Cluster ◽  
Open Clusters ◽  
Preliminary Results ◽  
Long Baseline ◽  
Trigonometric Parallax ◽  
Observational Program

AbstractThe Pleiades is the best-studied open cluster in the sky. It is one of the primary open clusters used to define the ‘zero-age main sequence,' and hence it serves as a cornerstone for programs which use main-sequence fitting to derive distances. This role is called into question by the ‘Pleiades distance controversy:' the distance to the Pleiades from Hipparcos of approximately 120 pc is significantly different from the distance of 133 pc derived using other techniques. To resolve this issue, we plan to use Very Long Baseline Interferometry to derive a new, independent trigonometric parallax distance to the Pleiades. In these proceedings we present our observational program and report some preliminary results.

Sign in / Sign up

Export Citation Format

Share Document