Estimates of Bolometric Corrections for WR Stars and Progenitors of WN Binaries

Using theoretical models of WR binary evolution, and adopting bolometric corrections for the O-type companions, the B.C. of a sample of WN stars are derived using the luminosity difference and the mass ratio. From the present characteristics of observed WN binaries the initial parameters are estimated assuming conservative case B of mass transfer and stellar wind as mass modifying processes. The influence of nonconservative interaction is discussed.

The criteria for dynamical mass transfer of the main-sequence donor stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312019679 ◽

2012 ◽

Vol 8 (S290) ◽

pp. 213-214

Author(s):

H. Ge ◽

R. F. Webbink ◽

X. Chen ◽

Z. Han

Keyword(s):

Mass Transfer ◽

Main Sequence ◽

Critical Mass ◽

Mass Ratio ◽

Dynamical Mass ◽

Common Envelope ◽

Binary Evolution ◽

Evolutionary Fate

AbstractMass transfer is very common in binary evolution and it dominates the evolutionary fate of binaries. Two crucial problems i.e. dynamical mass transfer and common envelope evolution, are not well understood yet. Here we focus on the first problem, and systematically show the critical mass ratio for dynamical mass transfer when the donor stars are still on the main sequence (MS).

Criterion for Dynamical Instability of Mass Transfer in Binary Evolution

10.1017/s0252921100001524 ◽

2002 ◽

Vol 187 ◽

pp. 297-302

Author(s):

Zhanwen Han ◽

Philipp Podsiadlowski ◽

Christopher A. Tout

Keyword(s):

Mass Transfer ◽

Angular Momentum ◽

Binary Systems ◽

Main Sequence ◽

Critical Mass ◽

Dynamical Instability ◽

Mass Ratio ◽

The Core ◽

Binary Evolution ◽

Red Giant

AbstractUsing Eggleton’s code, we performed a series of binary evolution calculations in order to investigate the criterion for dynamical instability of mass transfer in binaries. In these calculations, we took the donor’s mass on the zero-age main sequence (ZAMS) from 0.8 to 1.9 M⊙. For each mass, we systematically varied the mass of the core at the beginning of mass transfer and the mass of the companion star. We assumed that mass transfer was completely non-conservative and that all the mass that was lost from the system carried with it the orbital angular momentum of the accreting component. We found that the critical mass ratio, above which mass transfer is dynamically unstable, is from 1.1 to 1.3 in these red-giant binary systems.

Observational constraints from models of close binary evolution

Symposium - International Astronomical Union ◽

10.1017/s0074180900031211 ◽

1984 ◽

Vol 105 ◽

pp. 407-409

Author(s):

J.P. De Grève ◽

W. Packet

Keyword(s):

Mass Transfer ◽

Main Sequence ◽

Close Binary ◽

Second Phase ◽

Observational Constraints ◽

Mass Ratio ◽

Helium Burning ◽

Photometric Observations ◽

Early Case ◽

The evolution of a system of 9 MO + 5.4 MO is computed from Zero Age Main Sequence through an early case B of mass exchange, up to the second phase of mass transfer after core helium burning. Both components are calculated simultaneously. The evolution is divided into several physically different phases. The characteristics of the models in each of these phases are transformed into corresponding ‘observable’ quantities. The outlook of the system for photometric observations is discussed, for an idealized case. The influence of the mass of the loser, mli, and the initial mass ratio qi is considered.

Close binary evolution and blue straggler formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308023235 ◽

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 ◽

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.

Mass transfer and stellar wind effects in the eclipsing binary RT Andromedae

10.1017/s025292110009518x ◽

1981 ◽

Vol 59 ◽

pp. 491-494

Author(s):

G.A. Bakos ◽

J. Tremko

Keyword(s):

Mass Transfer ◽

Light Curve ◽

Spectral Type ◽

Orbital Period ◽

Stellar Wind ◽

Mass Ratio ◽

Eclipsing Binary ◽

Short Period ◽

Photometric Elements ◽

Number Of Authors

In recent years the short period eclipsing binary RT And has been studied extensively by a number of authors. From photo electric observations the light curve and the photometric elements were derived by Dean (1974) and Mancuso et al. (1979). The geometric dimensions of the binary confirm that the system is detached consisting of two stars of spectral type F8 V and KO V. The mass ratio is 0.66. In spite of this classification, effects appearing among semidetached systems have been observed, namely, variations of the amplitude and the shape of the light curve and changes of the length of the orbital period.

Twin stars as tracers of binary evolution in the Kepler era

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab343 ◽

2021 ◽

Author(s):

Sara Bulut ◽

Baris Hoyman ◽

Ahmet Dervisoglu ◽

Orkun Özdarcan ◽

Ömür Cakilrli

Keyword(s):

High Resolution ◽

Internal Structure ◽

Spectroscopic Analysis ◽

Independent Method ◽

Eclipsing Binaries ◽

Physical Parameters ◽

Evolutionary Status ◽

Mass Ratio ◽

Orbital Parameters ◽

Abstract We present results of the combined photometric and spectroscopic analysis of four systems, which are eclipsing binaries with a twin–component (mass ratio q ≃ 1). These are exceptional tools to provide information for probing the internal structure of stars. None of the systems were previously recognized as twin binaries. We used a number of high–resolution optical spectra to calculate the radial velocities and later combined them with photometry to derive orbital parameters. Temperatures and metallicities of systems were estimated from high-resolution spectra. For each binary, we obtained a full set of orbital and physical parameters, reaching precision below 3 per cent in masses and radii for whole pairs. By comparing our results with PARSEC and MIST isochrones, we assess the distance, age and evolutionary status of the researched objects. The primary and/or secondary stars of EPIC 216075815 and EPIC 202843107 are one of the cases where asteroseismic parameters of δ Sct and γ Dor pulsators were confirmed by an independent method and rare examples of the twin–eclipsing binaries, therefore the following analyses and results concern the pulsating nature of the components.

Mathematical modelling of the osmotic dehydration of physalis

BRAZILIAN JOURNAL OF FOOD TECHNOLOGY ◽

10.1590/1981-6723.10217 ◽

2018 ◽

Vol 21 (0) ◽

Author(s):

Fernanda Rosa Assis ◽

Rui Manuel Santos Costa de Morais ◽

Alcina Maria Miranda Bernardo de Morais

Keyword(s):

Mass Transfer ◽

Atmospheric Pressure ◽

Osmotic Dehydration ◽

Mass Ratio ◽

Promising Alternative ◽

Sucrose Solutions ◽

Mass Transfer Kinetics ◽

Osmotic Agent ◽

Effective Diffusivities ◽

Best Fit

Abstract Physalis was osmotically dehydrated with 60 °Bx sucrose or sorbitol solutions at 60 °C and with a mass ratio of sample to solution of 1:4, at atmospheric pressure or under vacuum at 150 mbar. The Crank’s, Peleg’s and Page’s models were tested to describe the mass transfer kinetics for water loss (WL) and solids gain (SG). The effective diffusivities of both water and solute were around 10-11 m2 s-1 under all conditions. Peleg’s model presented the best fit. The use of sorbitol as the osmotic agent resulted in an increase in the WL rate. In experiments with sucrose solutions, a higher WL was obtained under vacuum than at atmospheric pressure. The SG was particularly low during osmotic dehydration. Thus, the use of sorbitol as the osmotic agent was shown to be a promising alternative to sucrose.

Algols as Limits on Binary Evolution Scenarios

10.1017/s0252921100087753 ◽

1989 ◽

Vol 107 ◽

pp. 155-164

Author(s):

M.S. Hjellming

Keyword(s):

Mass Transfer ◽

Mass Loss ◽

Initial Mass ◽

Transfer Rates ◽

Successful Transition ◽

Evolutionary State ◽

Mass Ratios ◽

Binary Evolution ◽

Do So

AbstractEvolutionary scenarios must account for Algol binaries surviving their first phase of mass transfer. The outcome of this phase is dependent upon the rapidity of the initial mass transfer, which can be estimated by calculating the radial reponse of potential progenitors to mass loss. Limits on the donor’s evolutionary state, and its companion mass, can be placed on systems which would transfer mass on a thermal or dynamical timescale. Slower mass transfer rates are necessary for the successful transition to an Algol. Considering 1.5 and 5.0 M⊙ models, the former succeed in case A and Br systems, while the latter can do so only in case A systems. To evolve into an Algol binary, all systems seem to require initial mass ratios near one.

The influence of stellar wind mass loss on the evolution of massive close binaries.

Symposium - International Astronomical Union ◽

10.1017/s0074180900013796 ◽

1979 ◽

Vol 83 ◽

pp. 409-414

Author(s):

D. Vanbeveren ◽

J.P. De Grève ◽

C. de Loore ◽

E.L. van Dessel

Keyword(s):

Mass Loss ◽

Stellar Wind ◽

Binary Systems ◽

Mass Loss Rate ◽

Radiation Force ◽

Roche Lobe ◽

Close Binaries ◽

Massive Binary Systems ◽

Binary Evolution ◽

X Ray Binaries

It is generally accepted that massive (and thus luminous) stars lose mass by stellar wind, driven by radiation force (Lucy and Solomon, 1970; Castor et al. 1975). For the components of massive binary systems, rotational and gravitational effects may act together with the radiation force so as to increase the mass loss rate. Our intention here is to discuss the influence of a stellar wind mass loss on the evolution of massive close binaries. During the Roche lobe overflow phase, mass and angular momentum can leave the system. Possible reasons for mass loss from the system are for example the expansion of the companion due to accretion of the material lost by the mass losing star (Kippenhahn and Meyer-Hofmeister, 1977) or the fact that due to the influence of the radiation force in luminous stars, mass will be lost over the whole surface of the star and not any longer through a possible Lagrangian point as in the case of classical Roche lobe overflow (Vanbeveren, 1978). We have therefore investigated the influence of both processes on binary evolution. Our results are applied to 5 massive X-ray binaries with a possible implication for the existence of massive Wolf Rayet stars with a very close invisible compact companion. A more extended version of this talk is published in Astronomy and Astrophysics (Vanbeveren et al. 1978; Vanbeveren and De Grève, 1978). Their results will be briefly reviewed.

High Mass Ratio Contact Binaries: Recent Evolution into Contact?

10.1017/s0252921100088047 ◽

1989 ◽

Vol 107 ◽

pp. 348-349

Author(s):

Bruce J. Hrivnak

Keyword(s):

Mass Transfer ◽

Angular Momentum ◽

Primary Component ◽

High Mass ◽

Mass Ratio ◽

Origin And Evolution ◽

Momentum Loss ◽

Angular Momentum Loss ◽

Mass Ratios ◽

Contact Binaries

Recent theories of the origin and evolution of contact binaries suggest that the two stars evolve into contact through angular momentum loss (AML; Mochnacki 1981, Vilhu 1982). When in contact, the system then evolves toward smaller mass ratio through mass transfer from the secondary to the primary component (Webbink 1976, Rahunen and Vilhu 1982). Most contact binaries have mass ratios of 0.3 to 0.5.