A Comparison of Stellar Evolution with Binary Systems

1999 ◽  
Vol 521 (1) ◽  
pp. 297-301 ◽  
Author(s):  
Nobuyuki Iwamoto ◽  
Hideyuki Saio
Keyword(s):  
Stellar Evolution ◽  
Binary Systems

scholarly journals A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary

Science ◽  
2018 ◽  
Vol 362 (6411) ◽  
pp. 201-206 ◽  
Author(s):  
K. De ◽  
M. M. Kasliwal ◽  
E. O. Ofek ◽  
T. J. Moriya ◽  
J. Burke ◽  
...  
Keyword(s):  
Neutron Star ◽  
Kinetic Energy ◽  
Light Curve ◽  
Stellar Evolution ◽  
Binary Systems ◽  
Massive Stars ◽  
Compact Binary ◽  
Compact Binary Systems ◽  
Supernova Explosions ◽  
Star Binary

Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 1050ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor. Taken together, we interpret iPTF 14gqr as evidence for ultra-stripped supernovae that form neutron stars in compact binary systems.

scholarly journals Constraints on the Atmospheric Parameters of the Binary DA White Dwarf L870-2 (EG11)

1989 ◽  
Vol 114 ◽  
pp. 435-439
Author(s):  
P. Bergeron ◽  
F. Wesemael ◽  
J. Liebert ◽  
G. Fontaine ◽  
P. Lacombe
Keyword(s):  
Observational Data ◽  
Stellar Evolution ◽  
Effective Temperature ◽  
White Dwarf ◽  
Binary Systems ◽  
Absolute Magnitude ◽  
Atmospheric Parameters ◽  
Spectroscopic Binary ◽  
Short Period ◽  
Period System

The recent discovery that the cool DA white dwarf L870-2 (EG11, WD0135-052) is a double-lined spectroscopic binary composed of a detached pair of DA white dwarfs (Saffer, Liebert, and Olszewski 1988, SLO hereafter) has raised some challenging problems for stellar evolution theories of such binary systems. One first important step in the understanding of this short-period system is to establish the atmospheric parameters of each component. SLO have argued from previous determinations of the effective temperature and absolute magnitude of the system, and also from their own study of the composite Hα profile, that the two components should be similar. We wish here to reexamine this assertion by taking a new look at the constraints on the two components brought about by the available observational data.

scholarly journals Long-Term Spectroscopic Monitoring and Surveys of Early-Type Stars with and without Circumstellar Envelopes

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Anatoly S. Miroshnichenko ◽  
Steven Danford ◽  
Sergei V. Zharikov ◽  
Nadine Manset ◽  
Hugo Levato ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Binary Systems ◽  
Theoretical Explanation ◽  
Evolutionary Status ◽  
Early Type ◽  
Fundamental Parameters ◽  
Spectroscopic Monitoring ◽  
Early Type Stars ◽  
Large Telescopes

AbstractOngoing studies of different groups of stars result in improving our knowledge of their fundamental parameters and evolutionary status. Also, they result in finding new phases of stellar evolution, which require theoretical explanation. At the same time, availability of large telescopes and sensitivity improvement of detectors shift the focus of many observational programs toward fainter and more distant objects. However, there are still many problems in our understanding of details of stellar evolution which can now be solved with small telescopes and observations of bright stars. Approaching these problems implies conducting surveys of large groups of stars and long-term monitoring of individual objects. In this talk, we present the results of recent international programs of photometric and spectral monitoring of several groups of early-type stars. In particular, we discuss the role of binarity in creation of the Be phenomenon and show examples of recently discovered binary systems as well as the problem of refining fundamental parameters of B and A type supergiants. Special attention will be paid to collaboration with the amateur community and use of échelle spectrographs mounted on small telescopes.

scholarly journals IUE Ultraviolet Spectra of the Interacting Binary U Cephei

1980 ◽  
Vol 88 ◽  
pp. 237-241
Author(s):  
Yoji Kondo ◽  
George E. McCluskey ◽  
Robert E. Stencel
Keyword(s):  
High Resolution ◽  
Ultraviolet Light ◽  
Stellar Evolution ◽  
Binary Systems ◽  
Light Curves ◽  
Close Binary ◽  
Eclipsing Binary ◽  
Ultraviolet Spectra ◽  
International Ultraviolet Explorer ◽  
Far Ultraviolet

The eclipsing binary U Cephei has proven to be of great interest in the study of stellar evolution in close binary systems. Batten (1974), Hall and Walter (1974), Rhombs and Fix (1976), Markworth (1977), and Olson (1978), among others, have recently reported on their intensive ground based studies of U Cephei. Kondo, McCluskey and Wu (1978) have investigated the ultraviolet light curves of U Cephei obtained with Astronomical Netherlands Satellite (ANS). Kondo, McCluskey and Stencel (1979) have discussed the International Ultraviolet Explorer (IUE) spectra of U Cephei. This paper discusses results incorporating additional IUE high resolution spectra of U Cephei obtained in both far-ultraviolet and mid-ultraviolet spectral regions.

On the accretion of interstellar matter by stars

1940 ◽  
Vol 36 (3) ◽  
pp. 325-330 ◽  
Author(s):  
F. Hoyle ◽  
R. A. Lyttleton
Keyword(s):  
Stellar Evolution ◽  
Binary Systems ◽  
Galactic Plane ◽  
Small Mass ◽  
Average Density ◽  
Close Binary ◽  
Interstellar Matter ◽  
Satisfactory Description ◽  
Geological Evidence ◽  
The Galaxy

The rate of accretion of interstellar matter by stars as proposed in a previous paper is further discussed. It is shown that this amount, while sufficient for the evolution of the majority of stars, is insufficient by a factor of the order of 10 or more to give a satisfactory description of the general evolution of massive stars and close binary systems of small mass. Consideration of the possibility of increasing the rate of accretion for such exceptional stars leads to the conclusion that this can be carried out satisfactorily only by a corresponding increase in the density of the cloud. Although we were led to this view by considering all the factors involved in accretion and showing that only a change in the density could possibly produce the required increase, it is at once clear from the accretion formula, without detailed discussion of the other quantities involved, that the density is the only factor through which effects could be introduced that do not apply to all stars quite generally. By investigating the various factors in the galaxy affecting the density, it is shown that within 100 parsecs of the galactic plane, and also in local regions, the density may rise above 10−21 g. per c.c., which gives an increase of order 100 times the normal rate for stars lying in these regions. These suggestions receive independent corroboration from investigations by Jeans relating to extra-galactic nebulae which led to average densities also of order 10−21 g. per c.c., while a further argument from geological evidence shows that the average density of material along the sun's track must be higher than 10−21 g. per c.c. It remains to be seen whether future observations will succeed in confirming these suggestions indicated by the requirements of this theory of stellar evolution.

scholarly journals The i-process yields of rapidly accreting white dwarfs from multicycle He-shell flash stellar evolution models with mixing parametrizations from 3D hydrodynamics simulations

2019 ◽  
Vol 488 (3) ◽  
pp. 4258-4270 ◽  
Author(s):  
Pavel A Denissenkov ◽  
Falk Herwig ◽  
Paul Woodward ◽  
Robert Andrassy ◽  
Marco Pignatari ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
White Dwarfs ◽  
Binary Systems ◽  
Scaling Laws ◽  
Ingestion Rate ◽  
Three Dimensional ◽  
Close Binary ◽  
Convective Boundary ◽  
Retention Efficiency ◽  
Hydrodynamic Simulations

ABSTRACT We have modelled the multicycle evolution of rapidly accreting CO white dwarfs (RAWDs) with stable H burning intermittent with strong He-shell flashes on their surfaces for 0.7 ≤ MRAWD/M⊙ ≤ 0.75 and [Fe/H] ranging from 0 to −2.6. We have also computed the i-process nucleosynthesis yields for these models. The i process occurs when convection driven by the He-shell flash ingests protons from the accreted H-rich surface layer, which results in maximum neutron densities Nn, max ≈ 1013–1015 cm−3. The H-ingestion rate and the convective boundary mixing (CBM) parameter ftop adopted in the one-dimensional nucleosynthesis and stellar evolution models are constrained through three-dimensional (3D) hydrodynamic simulations. The mass ingestion rate and, for the first time, the scaling laws for the CBM parameter ftop have been determined from 3D hydrodynamic simulations. We confirm our previous result that the high-metallicity RAWDs have a low mass retention efficiency ($\eta \lesssim 10{{\ \rm per\ cent}}$). A new result is that RAWDs with [Fe/H] $\lesssim -2$ have $\eta \gtrsim 20{{\ \rm per\ cent}}$; therefore, their masses may reach the Chandrasekhar limit and they may eventually explode as SNeIa. This result and the good fits of the i-process yields from the metal-poor RAWDs to the observed chemical composition of the CEMP-r/s stars suggest that some of the present-day CEMP-r/s stars could be former distant members of triple systems, orbiting close binary systems with RAWDs that may have later exploded as SNeIa.

scholarly journals Interacting binaries: an excellent project for small telescopes

1986 ◽  
Vol 118 ◽  
pp. 173-186
Author(s):  
Mirek J. Plavec
Keyword(s):  
Mass Transfer ◽  
Transfer Process ◽  
Stellar Evolution ◽  
Binary Systems ◽  
Mass Transfer Process ◽  
Circumstellar Matter ◽  
Light Curves ◽  
Evolutionary Stage ◽  
Degenerate Component ◽  
Interacting Systems

Discussed are meritorious projects for small and moderate telescopes in the field of interacting binaries with non-degenerate component stars. These interacting binaries are undergoing a mass transfer process, as a consequence of which the mass-accreting star may be partly or completely hidden in an accretion disk, and the system may be shrouded in dense clouds of circumstellar matter. This makes the observation, interpretation and modeling difficult; but it is important to study these “bizarre” binaries since they tell us a lot about stellar evolution in binary systems. Needed are various observations: Timing of eclipses; observation and re-observation of light curves in several colors (in uvby rather than in UBV; and in the red and infrared); radial velocity studies; spectrophotometry of crucial regions of the spectrum. As examples for these needs, the following systems are discussed in some detail, and their problems revealed: RX Cassiopeiae, W Serpentis, and W Crucis as examples of the strongly interacting systems (W Serpentids); U Sagittarii as a helium-rich binary in a rare evolutionary stage, which will be better understood if we decide whether the star eclipses or not; and KX Andromedae as a representative of non-eclipsing interacting binaries and of Be and shell stars, which may or may not be binaries.

Stellar evolution in binary systems

1995 ◽  
Vol 58 (8) ◽  
pp. 885-928 ◽  
Author(s):  
A H Batten
Keyword(s):  
Stellar Evolution ◽  
Binary Systems

scholarly journals Observational Aspects of Stellar Evolution in the Upper HRD

1991 ◽  
Vol 143 ◽  
pp. 465-478
Author(s):  
Claus Leitherer
Keyword(s):  
Stellar Evolution ◽  
Surface Density ◽  
Binary Systems ◽  
Observational Evidence ◽  
Open Clusters ◽  
H Ii Regions ◽  
M 10 ◽  
Ob Associations ◽  
Spiral Arm ◽  
Galactic Distribution

Observational evidence strongly favors an evolutionary relation between Wolf-Rayet (WR) stars and stars with masses above ~ 10 M⊙. The galactic distribution of WR stars closely resembles the distribution of O stars both in the z-direction as well as in the spiral-arm pattern (Hidayat, Admiranto, and van der Hucht 1984, van der Hucht et al. 1988, Conti and Vacca 1990). Lundström and Stenholm (1984) found that the surface density of W R stars increases with decreasing distance from OB associations as well as from young open clusters. The fraction of WR stars in clusters turns out to be about the same as that of O stars. A large number of extragalactic WR stars is situated in giant H II regions, which also contain high numbers of very massive 0 stars (see, e.g., Walborn 1990 for 30 Doradus; Drissen, Moffat, and Shara 1990 for M33). Many WR stars are members of binary systems with well established parameters so that their masses can be determined directly. In several cases, WR-stax masses of M ≥ 10 M⊙ have been derived (Massey 1981, St.-Louis et al. 1987, Schulte-Ladbeck 1989).

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