scholarly journals The influence of close binary evolution on the age determination of starburst regions

1999 ◽  
Vol 193 ◽  
pp. 624-625 ◽  
Author(s):  
Joris Van Bever ◽  
H. Belkus ◽  
Dany Vanbeveren ◽  
Walter van Rensbergen
Keyword(s):  
Line Strength ◽  
Age Determination ◽  
Life Time ◽  
Close Binary ◽  
Minor Importance ◽  
Population Number ◽  
Blue Stragglers ◽  
Binary Evolution ◽  
Starburst Regions

Using a population number synthesis code and detailed massive star evolutionary calculations, we investigate the effect of close binary evolution on Hα and Hβ emission-line strength variation in starburst regions. The Hβ line strength especially, is considered as a good age indicator. We demonstrate that the formation of rejuvenated accretion stars (Blue Stragglers) through RLOF lengthens the life-time of the Hβ flux and makes the age determination of a starburst regions ambiguous. We separately calculate the effect of Wolf-Rayet stars and of X-ray binaries on Hα and Hβ and conclude that both are of minor importance.

scholarly journals Imaging the elusive H-poor gas in planetary nebulae with large abundance discrepancy factors

2016 ◽  
Vol 12 (S323) ◽  
pp. 65-69 ◽  
Author(s):  
Jorge García-Rojas ◽  
Romano L. M. Corradi ◽  
Henri M. J. Boffin ◽  
Hektor Monteiro ◽  
David Jones ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Tunable Filter ◽  
Close Binary ◽  
Chemical Abundances ◽  
Dual Nature ◽  
Gas Phases ◽  
Binary Evolution ◽  
The Universe ◽  
Central Stars

AbstractThe discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O ii ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O ii ORL emission is more centrally concentrated than that of [Oiii] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.

scholarly journals The effect of close binary evolution on the chemical enrichment of galaxies

1999 ◽  
Vol 193 ◽  
pp. 738-738
Author(s):  
Erwin De Donder ◽  
Dany Vanbeveren
Keyword(s):  
Binary Stars ◽  
Chemical Elements ◽  
Supernova Explosion ◽  
Close Binary ◽  
Binary Interaction ◽  
Interstellar Gas ◽  
Population Number ◽  
Chemical Enrichment ◽  
Type Ia ◽  
Binary Evolution

During their various evolutionary phases, stars enrich the interstellar gas (ISG) with chemical elements. In our study we investigate the effect of binaries on the chemical enrichment of the ISG. To derive the true yields for a population of single and binary stars we use a Population Number Synthesis code which is described in detail in Vanbeveren et al. (1998). We account for the enrichment through stellar wind (SW), supernova explosion (SN) of single and binary stars including type Ia, planetary nebula (PN), and through binary interaction (BI). When black hole (BH) formation occurs, it is assumed that all matter is swallowed by the hole. This happens for single stars with a mass larger than 25 M⊙ and for interacting binary components heavier than 40 M⊙. Type Ia SNe are treated according to the scenario of Li & van den Heuvel (1997). We conclude that including binaries: (a) increases the production of helium, up to a factor ∼ 1.8 for 100% binaries (note that the helium yield increases linearly with binary frequency); and (b) drastically changes the ratio of the relative helium to metallicity enrichment dY/dZ (even for Z = 0.02) resulting in values higher than 3.5 for binary frequencies ≥ 40%, which is in good agreement with the observations.

scholarly journals Blue Stragglers from Primordial Binary Evolution

2008 ◽  
Vol 4 (S252) ◽  
pp. 417-418
Author(s):  
Xuefei Chen ◽  
Zhanwen Han
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Close Binary ◽  
Spectral Energy ◽  
Population Synthesis ◽  
Blue Stragglers ◽  
Blue Straggler ◽  
Binary Evolution

AbstractBinaries exist in all clusters and much evidence suggests that close-binary evolution makes an important contribution to the blue straggler population, at least in some clusters as well as in the field. Here we present different channels to blue stragglers from primordial binary evolution and examine their contributions to the integrated spectral energy distribution of the host clusters in theory via binary population synthesis.

scholarly journals Evolution of binary stars and its implications for evolutionary population synthesis

2009 ◽  
Vol 5 (S262) ◽  
pp. 44-47
Author(s):  
Z. Han ◽  
X. Chen ◽  
F. Zhang ◽  
Ph. Podsiadlowski
Keyword(s):  
Binary System ◽  
Binary Stars ◽  
Elliptical Galaxies ◽  
Close Binary System ◽  
Close Binary ◽  
Population Synthesis ◽  
Blue Stragglers ◽  
Uv Excess ◽  
Hot Subdwarfs ◽  
Binary Evolution

AbstractMost stars are members of binaries, and the evolution of a star in a close binary system differs from that of an ioslated star due to the proximity of its companion star. The components in a binary system interact in many ways and binary evolution leads to the formation of many peculiar stars, including blue stragglers and hot subdwarfs. We will discuss binary evolution and the formation of blue stragglers and hot subdwarfs, and show that those hot objects are important in the study of evolutionary population synthesis (EPS), and conclude that binary interactions should be included in the study of EPS. Indeed, binary interactions make a stellar population younger (hotter), and the far-ultraviolet (UV) excess in elliptical galaxies is shown to be most likely resulted from binary interactions. This has major implications for understanding the evolution of the far-UV excess and elliptical galaxies in general. In particular, it implies that the far-UV excess is not a sign of age, as had been postulated prviously and predicts that it should not be strongly dependent on the metallicity of the population, but exists universally from dwarf ellipticals to giant ellipticals.

scholarly journals The Eclipsing Binaries in NGC 5466 and Implications for Close Binary Evolution

1992 ◽  
Vol 151 ◽  
pp. 483-486
Author(s):  
E. F. Milone ◽  
C. R. Stagg ◽  
J. Kallrath
Keyword(s):  
Globular Cluster ◽  
Eclipsing Binaries ◽  
Close Binary ◽  
Blue Stragglers ◽  
The Third ◽  
Short Period ◽  
Algol System ◽  
Binary Evolution

The three eclipsing binaries among the blue stragglers of the globular cluster NGC 5466 have been modeled. Two of the systems are contact systems and the third is a short-period Algol system. The results indicate that the systems are well on their way to merger, but the implications for the origin of blue-stragglers are less clear.

scholarly journals Low–Mass He WDs and Millisecond Pulsars Age Determination

2000 ◽  
Vol 177 ◽  
pp. 631-632
Author(s):  
J. Antipova ◽  
Ene Ergma ◽  
M. J. Sarna
Keyword(s):  
Neutron Stars ◽  
Orbital Period ◽  
Time Scale ◽  
Age Determination ◽  
Close Binary ◽  
Orbital Parameters ◽  
History Of ◽  
Low Mass ◽  
Binary Evolution ◽  
Red Giant

It is accepted that the formation of a millisecond binary pulsar (MBP) with a low–mass companion may be explained as the end–point of close binary evolution in which an old pulsar is spun–up by accretion from the red giant (Bhattacharaya & van den Heuvel 1991). In this paper we shall discuss the cooling properties of the helium white dwarfs (WD) in short orbital period MBP systems PSR J0437–4715, PSR J0751+1807 and PSR J1012+5307, without referring to the rotational history of neutron stars (NS).Below we discuss observational data for several system for which the results of our calculations (Sarna, Antipova, & Muslimov 1998; Sarna, Ergma, & Antipova 1999) may be applied, by taking into account the orbital parameters of the system, the pulsar spin-down time, and the WD cooling time-scale.

scholarly journals Impact of binary interaction on the evolution of blue supergiants

2019 ◽  
Vol 621 ◽  
pp. A22 ◽  
Author(s):  
E. J. Farrell ◽  
J. H. Groh ◽  
G. Meynet ◽  
R. Kudritzki ◽  
J. J. Eldridge ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Binary Systems ◽  
Large Fraction ◽  
Close Binary ◽  
Binary Interaction ◽  
Luminous Blue Variables ◽  
Orbital Periods ◽  
Binary Evolution ◽  
Future Work

A large fraction of massive stars evolve in interacting binary systems, which dramatically modifies the outcome of stellar evolution. We investigated the properties of blue supergiants in binary systems and whether they are suitable for extragalactic distance determinations using the flux-weighted gravity luminosity relationship (FGLR). This is a relationship between the absolute bolometric magnitude Mbol and the spectroscopically determined flux-weighted gravity gF = g/T4eff, where g is the surface gravity and Teff is the effective temperature. We computed a grid of binary stellar evolution models with MESA and use the v2.1 BPASS models to examine whether they are compatible with the relatively small scatter shown by the observed relationship. Our models have initial primary masses of 9–30 M⊙, initial orbital periods of 10–2511 days, mass ratio q = 0.9, and metallicity Z = 0.02. We find that the majority of primary stars that produce blue supergiant stages are consistent with the observed FGLR, with a small offset towards brighter bolometric magnitudes. In between 1%–24% of cases, binary evolution may produce blue supergiants after a mass transfer episode, that lie below the observed FGLR. A very small number of such stars have been found in extragalactic FGLR studies, suggesting that they may have evolved through binary interaction. Some models with shorter periods could resemble blue hypergiants and luminous blue variables. We used CMFGEN radiative transfer models to investigate the effects of unresolved secondaries on diagnostics for Teff and g, and the biases on the determination of interstellar reddening and Mbol. We find that the effects are small and within the observed scatter, but could lead to a small overestimate of the luminosity, of Teff and of g for extreme cases. We conclude that the observed FGLR can, in principle, be well reproduced by close binary evolution models. We outline directions for future work, including rotation and binary population synthesis techniques.

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.

Analysis of Fibronectin and TGF-β1 Immunoexpression to Determination of Wound Vitality in Wistar Rats (Rattus norvegicus)

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Nita Novita ◽  
Hasrayati Agustina ◽  
Bethy S. Hernowo ◽  
Abdul H. Hassan
Keyword(s):  
Rattus Norvegicus ◽  
Wistar Rats ◽  
Age Determination ◽  
Scientific Field ◽  
Wound Age ◽  
Forensic Practice ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Tgf Β1

Wound examination is indispensable in forensic practice. The scientific field of wound age determination has advanced progressively during recent years.The purpose of this study was to determine the differences of fibronectin and TGF-β1 expression in both antemortem and postmortem wounds. This study was an experimental with completely randomized design.  The skin wounds (vital and postmortem) were taken from fourty Wistar rats and divided into 10 groups of rats. Immunohistochemical staining was performed to determine the differences between antemortem and postmortem wounds. The result showed that in 30 minutes after antemortem wound infliction, all of samples showed weak reactivity for fibronectin and TGF-β1 (100%).  In first hour after wound infliction, 3 samples (75%) showed weakly positive and 1 sample (25%) strongly positive for fibronectin and TGF-β1.  In 2 hour after wound infliction, 1 sample (25%) showed weakly positive and 3 sample (75%) strongly positive for fibronectin and TGF-β1.  In 3 and 4 hour after wound infliction, all of samples strongly positive for fibronectin and TGF-β1.  In postmortem wound, all of samples showed negativity for fibronectin and TGF-β1. In conclusion, fibronectin and TGF-β1 may be useful in the determination of wound vitality. Keywords: wound, fibronectin, TGF-β1, vitality

Sign in / Sign up

Export Citation Format

Share Document