scholarly journals A mass transfer origin for blue stragglers in NGC 188 as revealed by half-solar-mass companions

Nature ◽  
2011 ◽  
Vol 478 (7369) ◽  
pp. 356-359 ◽  
Author(s):  
Aaron M. Geller ◽  
Robert D. Mathieu
Keyword(s):  
Mass Transfer ◽  
Solar Mass ◽  
Blue Stragglers ◽  
Transfer Origin

scholarly journals On isolated millisecond pulsars formed by the coalescence of neutron stars and massive white dwarfs

2019 ◽  
Vol 36 ◽  
Author(s):  
Shengnan Sun ◽  
Lin Li ◽  
Helei Liu ◽  
Guoliang Lü ◽  
Zhaojun Wang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Neutron Star ◽  
Neutron Stars ◽  
White Dwarf ◽  
White Dwarfs ◽  
Birth Rate ◽  
Population Synthesis ◽  
Solar Mass ◽  
Millisecond Pulsars ◽  
The Stability

Abstract This paper uses population synthesis to investigate the possible origin of isolated millisecond pulsars as born from the coalescence of a neutron star and a white dwarf. Results show that the galactic birth rate of isolated millisecond pulsars is likely to lie between 5.8×10−5 yr−1 and 2.0×10−4 yr−1, depending on critical variables, such as the stability of mass transfer via the Roche lobe and the value of kick velocity. In addition to this, this paper estimates that the solar mass of isolated millisecond pulsars can range from 1.5 and 2.0 Mʘ, making them more massive than other ‘normal’ pulsars. Finally, the majority of isolated millisecond pulsars in our simulations have spin periods ranging from several to 20 ms, which is consistent with previous observations.

scholarly journals The blue stragglers formed via mass transfer in old open clusters

2006 ◽  
Vol 455 (1) ◽  
pp. 247-254 ◽  
Author(s):  
B. Tian ◽  
L. Deng ◽  
Z. Han ◽  
X. B. Zhang
Keyword(s):  
Mass Transfer ◽  
Open Clusters ◽  
Blue Stragglers

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 DETECTION OF WHITE DWARF COMPANIONS TO BLUE STRAGGLERS IN THE OPEN CLUSTER NGC 188: DIRECT EVIDENCE FOR RECENT MASS TRANSFER

2014 ◽  
Vol 783 (1) ◽  
pp. L8 ◽  
Author(s):  
Natalie M. Gosnell ◽  
Robert D. Mathieu ◽  
Aaron M. Geller ◽  
Alison Sills ◽  
Nathan Leigh ◽  
...  
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
Direct Evidence ◽  
Open Cluster ◽  
Blue Stragglers

scholarly journals A VLT/FLAMES survey for massive binaries in Westerlund 1

2019 ◽  
Vol 623 ◽  
pp. A83 ◽  
Author(s):  
J. S. Clark ◽  
F. Najarro ◽  
I. Negueruela ◽  
B. W. Ritchie ◽  
C. González-Fernández ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Binary Systems ◽  
Model Atmosphere ◽  
Detailed Examination ◽  
Single Star ◽  
X Ray ◽  
Cluster Membership ◽  
Blue Stragglers ◽  
Multi Wavelength ◽  
Velocity Changes

Context. Recent observational studies indicate that a large number of OB stars are found within binary systems which may be expected to interact during their lifetimes. Significant mass transfer or indeed merger of both components is expected to modify evolutionary pathways, facilitating the production of exceptionally massive stars which will present as blue stragglers. Identification and characterisation of such objects is crucial if the efficiency of mass transfer is to be established; a critical parameter in determining the outcomes of binary evolutionary channels. Aims. The young and coeval massive cluster Westerlund 1 hosts a rich population of X-ray bright OB and Wolf–Rayet stars where the emission is attributed to shocks in the wind collision zones of massive binaries. Motivated by this, we instigated a study of the extremely X-ray luminous O supergiants Wd1-27 and -30a. Methods. We subjected a multi-wavelength and -epoch photometric and spectroscopic dataset to quantitative non-LTE model atmosphere and time-series analysis in order to determine fundamental stellar parameters and search for evidence of binarity. A detailed examination of the second Gaia data release was undertaken to establish cluster membership. Results. Both stars were found to be early/mid-O hypergiants with luminosities, temperatures and masses significantly in excess of other early stars within Wd1, hence qualifying as massive blue stragglers. The binary nature of Wd1-27 remains uncertain but the detection of radial velocity changes and the X-ray properties of Wd1-30a suggest that it is a binary with an orbital period ≤10 days. Analysis of Gaia proper motion and parallactic data indicates that both stars are cluster members; we also provide a membership list for Wd1 based on this analysis. Conclusions. The presence of hypergiants of spectral types O to M within Wd1 cannot be understood solely via single-star evolution. We suppose that the early-B and mid-O hypergiants formed via binary-induced mass-stripping of the primary and mass-transfer to the secondary, respectively. This implies that for a subset of objects massive star-formation may be regarded as a two-stage process, with binary-driven mass-transfer or merger yielding stars with masses significantly in excess of their initial “birth” mass.

Binary evolution and double sequences of blue stragglers in globular clusters

2018 ◽  
Vol 14 (S343) ◽  
pp. 427-428
Author(s):  
Dengkai Jiang ◽  
Xuefei Chen ◽  
Lifang Li ◽  
Zhanwen Han
Keyword(s):  
Mass Transfer ◽  
Globular Clusters ◽  
Double Sequences ◽  
Single Star ◽  
Blue Stragglers ◽  
Blue Straggler ◽  
Magnitude Diagram ◽  
Blue Component ◽  
Binary Evolution ◽  
Red Sequence

AbstractBinary evolution can produce different blue-straggler binaries, for example, blue stragglers with a bright, red component, or with a faint, blue component. In globular clusters, these blue-straggler binaries are generally observed as a single star, because two components can not be distinguished. Therefore, these blue-straggler binaries can be located in different regions of the color-magnitude diagram of globular clusters, e.g. blue sequence and red sequence observed in M30. We suggest that binary evolution can contribute to the blue stragglers in both of the sequences. Some blue stragglers in the blue sequence may have a faint white dwarf companion, while the red sequence includes some binaries experiencing mass transfer. It should be noted that the red sequence may also have other binaries, for example, the binaries just finished the mass transfer, and the binaries including a blue straggler (the accretors) that have evolved away from the blue sequence.

scholarly journals Close binary evolution and blue straggler formation

2008 ◽  
Vol 4 (S252) ◽  
pp. 371-377
Author(s):  
P. Lu. ◽  
L. Deng
Keyword(s):  
Mass Transfer ◽  
Stellar Evolution ◽  
Close Binary ◽  
Close Binaries ◽  
Evolutionary Models ◽  
Mass Ratio ◽  
Blue Stragglers ◽  
Blue Straggler ◽  
Young Clusters ◽  
Binary Evolution

AbstractIn order to discuss the contribution of mass transfer in primordial close binaries to the blue straggler population in young clusters, we use Eggleton's stellar evolution code to simulate a grid of case A binary evolutionary models with the initial donor mass 2.0 – 8.0 M⊙ and mass ratio 0.1 – 0.9. The models cover the whole case A binaries that will experience mass transfer between 30.0 Myr to 1.0 Gyr. Based on such detailed models, we present a simulation to compare with the HST observation of young cluster NGC 1831 which can be fit with an isochrone of log(age) = 8.65. The results show very few blue stragglers could be produced by case A binary evolution. There must be some other mechanisms for blue straggler formation in young clusters.

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