UOCS. IV. Discovery of diverse hot companions to blue stragglers in the old open cluster King 2

AbstractFor almost 400 members of M67 we have accumulated about 5,000 precise radial velocities. Already we have orbital solutions for more than 32 spectroscopic binaries in M67. Many of these orbits were derived by combining the Palomar and CfA observations, thus extending the time coverage to more than 20 years. The distribution of eccentricity versus period shows evidence for tidal circularization on the main sequence. The transition from circular orbits is fairly clean. Excluding the blue stragglers, the first eccentric orbit has a period of 11.0 days, while the last circular orbit has a period of 12.4 days. For longer periods the distribution of eccentricity is the same as for field stars. The blue straggler S1284 has an eccentric orbit despite its short period of 4.2 days.

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The oscillating blue stragglers in the open cluster M67

The Astronomical Journal ◽

10.1086/116203 ◽

1992 ◽

Vol 103 ◽

pp. 1945 ◽

Cited By ~ 18

Author(s):

Ronald L. Gilliland ◽

Timothy M. Brown

Keyword(s):

Open Cluster ◽

Blue Stragglers

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Star Cluster Simulations on HARP

Symposium - International Astronomical Union ◽

10.1017/s0074180900001492 ◽

1996 ◽

Vol 174 ◽

pp. 161-170 ◽

Cited By ~ 7

Author(s):

Sverre J. Aarseth

Keyword(s):

Gravitational Radiation ◽

Cluster Model ◽

Open Cluster ◽

Star Cluster ◽

Peak Performance ◽

Strong Interactions ◽

Common Envelope ◽

Blue Stragglers ◽

New Formulation ◽

Evolution Type

We describe some aspects of implementing star cluster simulations on HARP. The code NBODY4 employs the Hermite scheme with hierarchical block-steps for direct integration. The algorithms have been optimized for parallel processing with the eight pipeline HARP-2 delivering a peak performance of about 1.7 Gflops for N = 104 particles. Hard binaries are studied by KS regularization which also uses the Hermite scheme, whereas strong interactions between 3–5 particles are treated by chain regularization. Astrophysical processes modelled include mass loss by stellar evolution, two-body tidal interaction, Roche lobe mass transfer, common envelope evolution, magnetic braking and gravitational radiation. Consistent values of stellar radii and evolution type are obtained by fast look-up. A new formulation of collision outcomes yields blue stragglers and other exotic objects. Some recent results for an open cluster model are presented.

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A Spectroscopic Study of Blue Stragglers in M67

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308023284 ◽

2008 ◽

Vol 4 (S252) ◽

pp. 391-397

Author(s):

G. Q. Liu ◽

L. Deng ◽

M. Chávez ◽

E. Bertone

Keyword(s):

Effective Temperature ◽

Spectral Properties ◽

Main Sequence ◽

Open Cluster ◽

Observational Constraints ◽

Photometric System ◽

Main Sequence Stars ◽

Complete Sample ◽

Blue Stragglers ◽

Fitting Method

AbstractSpectrophotometric observations of the complete sample of twenty four blue stragglers (BSs) in the old galactic open cluster M67 (NGC2682) have been collected, using the Guillermo Haro Observatory in Cananea, Mexico. All the calibrated spectra were re-calibrated by the Beijing Arizona Taipei Connecticut (BATC) photometric system which includes fluxes in 11 photometric bands covering ~3600–10000 Å. The goal of the current work is to provide observational constraints on spectral properties of BSs by determining the effective temperature (Teff) and surface gravity (log g). The overall results, obtained by applying the flux fitting method, indicate that Teff and surface gravities of BSs in M67 are fully compatible with those expected for main sequence stars.

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The spatial distribution of spectroscopic binaries and blue stragglers in the open cluster M67

The Astronomical Journal ◽

10.1086/114269 ◽

1986 ◽

Vol 92 ◽

pp. 1364 ◽

Cited By ~ 57

Author(s):

Robert D. Mathieu ◽

David W. Latham

Keyword(s):

Spatial Distribution ◽

Open Cluster ◽

Spectroscopic Binaries ◽

Blue Stragglers

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Models of M 67

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307011283 ◽

2006 ◽

Vol 2 (14) ◽

pp. 442-443

Author(s):

Jarrod R. Hurley

Keyword(s):

Open Cluster ◽

Stellar Populations ◽

Test Case ◽

Full Account ◽

Blue Stragglers ◽

Cluster Evolution ◽

Cluster Environment ◽

Binary Evolution ◽

X Ray Binaries

AbstractThe old open cluster M 67 is an ideal test case for current star cluster evolution models because of its dynamically evolved structure and rich stellar populations that show clear signs of interaction between stellar, binary and cluster evolution. Here we discuss a direct N-body model of M 67. This model of 12,000 single stars and 12,000 binaries is evolved from zero-age and takes full account of cluster dynamics as well as stellar and binary evolution. At an age of 4 Gyr the model cluster matches the mass and structure of M 67 as constrained by observations. We discuss the role of the primordial binary population and the cluster environment in shaping the nature of the stellar populations of M 67, with a focus on X-ray binaries and blue stragglers.

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Are All Blue Stragglers Ap Stars?

International Astronomical Union Colloquium ◽

10.1017/s0252921100080672 ◽

1976 ◽

Vol 32 ◽

pp. 357-364

Author(s):

E.S. Pendl ◽

W. Seggewiss

Keyword(s):

Spectroscopic Data ◽

Open Cluster ◽

Open Clusters ◽

Blue Stragglers ◽

The Status ◽

Ap Stars

SummaryA list of open clusters with blue stragglers studied for Ap characteristics is presented. In addition to previously published results new spectroscopic data are given of blue stragglers in the open cluster IC 4756 derived from ESO spectrograms taken in 1973. Preliminary conclusions concerning the status of Ap stars and blue stragglers are drawn.

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Spectroscopic binaries in M 67

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307011295 ◽

2006 ◽

Vol 2 (14) ◽

pp. 444-445 ◽

Cited By ~ 6

Author(s):

David W. Latham

Keyword(s):

Radial Velocity ◽

Open Cluster ◽

Spectroscopic Binaries ◽

Blue Stragglers

AbstractWe summarize the characteristics of 85 spectroscopic orbits derived from more than two decades of radial-velocity monitoring of stars in the old open cluster M 67, with special emphasis on the blue stragglers and other members that do not fall on the evolutionary tracks expected for isolated single stars.

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