HD 226766: a hierarchical SB3 system with two twin Am stars

2019 ◽  
Vol 487 (1) ◽  
pp. 919-927 ◽  
Author(s):  
G Catanzaro ◽  
M Gangi ◽  
M Giarrusso ◽  
M Munari ◽  
F Leone
Keyword(s):  
Chemical Composition ◽  
Main Sequence ◽  
Point Of View ◽  
Eccentric Orbit ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Component C ◽  
Effective Temperatures ◽  
Chemical Anomalies ◽  
The Masses

ABSTRACT In this paper, we present a detailed revision of the orbital parameters and the first quantitative abundance analysis of the spectroscopic triple system HD 226766. By means of a simultaneous fit of the radial velocities of all the three components, we derived precise orbital parameters for the system, in particular inner pair has P(d)  =  31.9187 ± 0.0001, e  =  0.28 ± 0.01, and MA/MB  = 1.03 ± 0.03, while the C component orbits around the inner pair with a period of P(d)  =  1615 ± 59 in a very eccentric orbit (e  =  0.54 ± 0.11). From the fit of the Hβ and Hα profiles, we determined the effective temperatures and surface gravities of each component of the inner pair: Teff  =  8600 ± 500 K and log g  =  3.8 ± 0.2 for HD 226766 A and Teff  =  8500 ± 400 K and log g  =  4.0 ± 0.2 for HD 226766 B. In the hypothesis that component C is a main sequence star (log g  =  4.0) we derived Teff  =  8000 ± 500 K. Rotational velocities have been estimated by modeling the profiles of metallic lines: v sin i  =  13 ± 1 km s−1 for inner pair and v sin i  =  150 ± 20 km s−1 for the C component. We find that the inner pair is heterogeneous from the point of view of the chemical composition: both stars are very similar and show chemical anomalies typical of Am stars. With some hypothesis about the masses of the components, we estimated the orbital inclination angle for the inner binary, i = (47 ± 1)○, and for the outer orbit, i = (54 ± 19)○.

scholarly journals WASP 0639-32: a new F-type subgiant/K-type main-sequence detached eclipsing binary from the WASP project

2018 ◽  
Vol 615 ◽  
pp. A135 ◽  
Author(s):  
J. A. Kirkby-Kent ◽  
P. F. L. Maxted ◽  
A. M. Serenelli ◽  
D. R. Anderson ◽  
C. Hellier ◽  
...  
Keyword(s):  
Binary System ◽  
Main Sequence ◽  
Mass Density ◽  
Helium Abundance ◽  
Eclipsing Binary ◽  
Abundance Estimate ◽  
Secondary Star ◽  
Free Parameters ◽  
Effective Temperatures ◽  
The Masses

Aims. Our aim is to measure the masses and radii of the stars in a newly-discovered detached eclipsing binary system to a high precision (≈1%), enabling the system to be used for the calibration of free parameters in stellar evolutionary models. Methods. Photometry from the Wide Angle Search for Planets (WASP) project was used to identify 1SWASP J063930.33-322404.8 (TYC 7091-888-1, WASP 0369-32 hereafter) as a detached eclipsing binary system with total eclipses and an orbital period of P = 11.66 days. Lightcurve parameters for WASP 0639-32 are obtained using the EBOP lightcurve model, with standard errors evaluated using a prayer-bead algorithm. Radial velocities were measured from 11 high-resolution spectra using a broadening function approach, and an orbit was fitted using SBOP. Observed spectra were disentangled and an equivalent width fitting method was used to obtain effective temperatures and metallicities for both stars. A Bayesian framework is used to explore a grid of stellar evolution models, where both helium abundance and mixing length are free to vary, and use observed parameters (mass, density, temperature, and metallicity) for each star to obtain the age and constrain the helium abundance of the system. Results. The masses and radii are found to be M1 = 1.1544 ± 0.0043 M⊙, R1 = 1.833 ± 0.023 R⊙, and M2 = 0.7833 ± 0.0028 M⊙, R2 = 0.7286 ± 0.0081 R⊙ for the primary and secondary, respectively. The effective temperatures were found to be T1 = 6330 ± 50 K and T2 = 5400 ± 80 K for the primary and secondary star, respectively. The system has an age of 4.2−0.1+0.8 Gyr, and a helium abundance in the range 0.251–0.271. Conclusions. WASP 0639-32 is a rare example of a well-characterised detached eclipsing binary system containing a star near the main-sequence turn-off point. This makes it possible to measure a precise age for the stars in this binary system and to estimate their helium abundance. Further work is needed to explore how this helium abundance estimate depends on other free parameters in the stellar models.

scholarly journals Barium and related stars, and their white-dwarf companions

2019 ◽  
Vol 626 ◽  
pp. A128 ◽  
Author(s):  
A. Escorza ◽  
D. Karinkuzhi ◽  
A. Jorissen ◽  
L. Siess ◽  
H. Van Winckel ◽  
...  
Keyword(s):  
Radial Velocity ◽  
White Dwarf ◽  
Main Sequence ◽  
Mass Function ◽  
Orbital Evolution ◽  
Asymptotic Giant Branch ◽  
Second Phase ◽  
Evolutionary Models ◽  
Orbital Inclination ◽  
Orbital Parameters

Barium (Ba) dwarfs and CH subgiants are the less evolved analogues of Ba and CH giants. They are F- to G-type main-sequence stars polluted with heavy elements by their binary companions when the companion was on the asymptotic giant branch (AGB). This companion is now a white dwarf that in most cases cannot be directly detected. We present a large systematic study of 60 objects classified as Ba dwarfs or CH subgiants. Combining radial-velocity measurements from HERMES and SALT high-resolution spectra with radial-velocity data from CORAVEL and CORALIE, we determine the orbital parameters of 27 systems. We also derive their masses by comparing their location in the Hertzsprung–Russell diagram with evolutionary models. We confirm that Ba dwarfs and CH subgiants are not at different evolutionary stages, and that they have similar metallicities, despite their different names. Additionally, Ba giants appear significantly more massive than their main-sequence analogues. This is likely due to observational biases against the detection of hotter main-sequence post-mass-transfer objects. Combining our spectroscopic orbits with the HIPPARCOS astrometric data, we derive the orbital inclination and the mass of the WD companion for four systems. Since this cannot be done for all systems in our sample yet (but should be possible with upcoming Gaia data releases), we also analyse the mass-function distribution of our binaries. We can model this distribution with very narrow mass distributions for the two components and random orbital orientations on the sky. Finally, based on BINSTAR evolutionary models, we suggest that the orbital evolution of low-mass Ba systems can be affected by a second phase of interactions along the red giant branch of the Ba star, which impact the eccentricities and periods of the giants.

scholarly journals Wolf-Rayet Stars with Massive Companions

1982 ◽  
Vol 99 ◽  
pp. 251-262 ◽  
Author(s):  
Philip Massey
Keyword(s):  
Fundamental Property ◽  
Mass Ratio ◽  
Orbital Inclination ◽  
Effective Temperatures ◽  
The Masses

The study of Wolf-Rayet binaries is important for the information we can gleam about the most fundamental property of any star: its mass. In this regard we are very fortunate, since the masses of WR stars can be determined with far greater confidence than can their luminosities, compositions, colors, effective temperatures, etc. By simply measuring the velocities of both components in a WR+0 system, we can find the minimum masses and the mass ratio of the two stars; if we can get some further handle on the orbital inclination, we then know the mass of the WR star directly.

scholarly journals Massive Stars: Evolution with Mass Loss. III. Low Metal Stars, and WR's in SMC

1980 ◽  
Vol 85 ◽  
pp. 107-107 ◽  
Author(s):  
C. Chiosi ◽  
G. Bertelli ◽  
E. Nasi
Keyword(s):  
Chemical Composition ◽  
Mass Loss ◽  
Metal Content ◽  
Main Sequence ◽  
Constant Mass ◽  
Initial Chemical Composition ◽  
The Galaxy ◽  
Metal Abundance ◽  
Effective Temperatures ◽  
Stars Evolution

In this paper we investigate the effect of mass loss by stellar wind on the evolution from the main sequence to the He exhaustion stage of stars in the range of mass 20 to 100 M⊙ with low metal abundance. To this purpose we compute the set of evolutionary sequences with initial mass 20, 30, 40, 60, 80, and 100 M⊙ and chemical composition parameters X=0.700, Z=0.001. The models are first computed at constant mass to provide the fundamental network to which we compare the mass losing models. This choice of the initial chemical composition is aimed to represent the case of luminous supergiants in the Small Magellanic Cloud. The rate of mass loss follows the formulation of Castor, Abbot and Klein (1975), but it incorporates the effect of different metal content in the regions of high effective temperatures in the HR diagram. The rate of mass loss for models at low effective temperature is given by the acoustic flux mechanism according to the formulation of Chiosi, Nasi and Sreenivasan (1978). The results are compared with those of Chiosi, Nasi and Sreenivasan (1978), and those of Chiosi, Nasi and Bertelli (1979) for normal metal abundance supergiant stars of the Galaxy. On the basis of the present results we suggest an interpretative scenario for the existence of single WR stars in galaxies of different chemical composition. These results allow us to interpret also the different percentages of WR's among subclasses that are observed in the Galaxy, LMC, and SMC (Conti and Vanbeveren, 1979).

scholarly journals Physical Parameters and Chemical Composition of Components of the Am-Type Binary System RR Lyncis

1993 ◽  
Vol 138 ◽  
pp. 192-196
Author(s):  
L.S. Lyubimkov ◽  
T.M. Rachkovskaya
Keyword(s):  
Chemical Composition ◽  
Binary System ◽  
Binary Stars ◽  
Spectroscopic Binaries ◽  
Theoretical Modelling ◽  
Physical Parameters ◽  
Accurate Data ◽  
Element Abundances ◽  
Widespread Phenomenon ◽  
Chemical Anomalies

Duplicity is a very widespread phenomenon among Am-stars. For instance, Abt (1961) investigating 25 such stars found out that 22 of them are spectroscopic binaries. However this important phenomenon is ignored usually in chemical composition investigations of Am-stars. Consequently some “mean” element abundances are determined, which can noticeably differ from real abundances in atmospheres of components. Moreover false chemical anomalies can appear, as shown by the theoretical modelling of spectra of binary stars (Lyubimkov, 1989, 1992). Meanwhile accurate data on chemical composition of Am-stars must be considered as observational test for any hypothesis suggested for explanation of these objects.

scholarly journals On the origin of the helium-rich population in the peculiar globular cluster Omega Centauri

2009 ◽  
Vol 5 (S268) ◽  
pp. 187-188
Author(s):  
Donatella Romano ◽  
M. Tosi ◽  
M. Cignoni ◽  
F. Matteucci ◽  
E. Pancino ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Globular Cluster ◽  
Main Sequence ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Potential Well ◽  
Galactic Winds ◽  
Supernova Explosions

AbstractIn this contribution we discuss the origin of the extreme helium-rich stars which inhabit the blue main sequence (bMS) of the Galactic globular cluster Omega Centauri. In a scenario where the cluster is the surviving remnant of a dwarf galaxy ingested by the Milky Way many Gyr ago, the peculiar chemical composition of the bMS stars can be naturally explained by considering the effects of strong differential galactic winds, which develop owing to multiple supernova explosions in a shallow potential well.

scholarly journals Chemical Composition and Functional Properties of Dietary Fibre Concentrates from Winemaking By-Products: Skins, Stems and Lees

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1510
Author(s):  
María Ángeles Rivas ◽  
Rocío Casquete ◽  
María de Guía Córdoba ◽  
Santiago Ruíz-Moyano ◽  
María José Benito ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Functional Properties ◽  
Dietary Fibre ◽  
Water Retention ◽  
Point Of View ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Oil Retention ◽  
High Antioxidant Activity ◽  
By Products

The objective of this study was to evaluate, from a technological and nutritional point of view, the chemical composition and functional properties of the industrial winemaking by-products, namely skins, stems and lees. The chemical and physical characteristics, as well as the functional properties (fat and water retention and swelling capacity, antioxidant capacity, and their prebiotic effect), of the dietary fibre of these by-products were studied. The results showed that the skins, stems, and lees are rich in fibre, with the stem fibre containing the highest amounts of non-extractable polyphenols attached to polysaccharides with high antioxidant activity and prebiotic effect. Lee fibre had the highest water retention capacity and oil retention capacity. The results reveal that winemaking by-products could be used as a source of dietary fibre with functional characteristics for food applications.

scholarly journals Pulsars in Globular Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 291-300 ◽  
Author(s):  
Scott M. Ransom
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Globular Clusters ◽  
Main Sequence ◽  
Galactic Disk ◽  
Nuclear Density ◽  
Millisecond Pulsars ◽  
Eccentric Orbits ◽  
The Masses ◽  
Current Record

AbstractGlobular clusters produce orders of magnitude more millisecond pulsars per unit mass than the Galactic disk. Since the first cluster pulsar was uncovered 20 years ago, at least 138 have been identified – most of which are binary millisecond pulsars. Because their origins involve stellar encounters, many of the systems are exotic objects that would never be observed in the Galactic disk. Examples include pulsar-main sequence binaries, extremely rapid rotators (including the current record holder), and millisecond pulsars in highly eccentric orbits. These systems are allowing new probes of the interstellar medium, the equation of state of material at supra-nuclear density, the masses of neutron stars, and globular cluster dynamics.

"Om Alle Menschen Wel Te Leren Sterven"

1986 ◽  
Vol 66 (2) ◽  
pp. 148-179
Author(s):  
E.J.G. Lips
Keyword(s):  
Point Of View ◽  
Religious Communities ◽  
Original Text ◽  
The Public ◽  
Ars Moriendi ◽  
Text Types ◽  
Dutch Language ◽  
The Masses

AbstractThe genre of the Ars moriendi is by no means a homogeneous one. Indeed, the great textual diversity has more than once attracted the attention. This diversity, caused by various omissions and, more often, extensions in the original text-types, is often considered as the decay of an originally orthodox theological genre. In this essay, manuscripts and printed versions of the Ars moriendi in the Dutch language ( ± 1450-1530) are studied. Instead of considering the omissions and extensions meant above as a decline of the genre, the author attempts to regard them, as the medieval writers may have done, as means to make the texts find their way to the public more easily. Various methods used by the authors of these Artes to reach their public, are examined and their presumable succes is evaluated. It seems that, whereas particularly the older literature assumes an almost infinite public, recent research does not confirm this point of view. For, in spite of explicit remarks addressed to all christians, commerce dictated to the printers a more or less wealthy public. As for the manuscripts, these seem mainly to have had a public of clergy and (female) religious communities. However, considering the existence of a public of listeners, both manuscripts and printed versions had, in an indirect way, their impact on the masses of the christians.

YIELD, ECONOMICALLY VALUABLE INDICATORS AND CHEMICAL COMPOSITION OF BLUE HONEYSUCKLE UNDER CONDITIONS OF SAKHALIN TRADE-WIND LITTORAL CLIMATE

2021 ◽  
pp. 64-73
Author(s):  
V.N. Yefanov ◽  
◽  
E.V. Mitusova ◽  
Keyword(s):  
Chemical Composition ◽  
Point Of View ◽  
Trade Wind ◽  
Plant Industry ◽  
Monsoon Climate ◽  
Experimental Station ◽  
Vavilov Institute ◽  
Household Gardens ◽  
Blue Honeysuckle

The blue honeysuckle is the earliest ripening berry, which ripens 7–10 days earlier than the garden strawber-ries under the conditions of Sakhalin's climate. It is resistant to lower fungi and parasites and can be cultivat-ed without pesticides. Currently, many honeysuckle varieties with fruits of different morphologies and chemical composition have been bred. We analyzed values of economically valuable indicators and chemical composition in 14 varieties of honeysuckle, which grow in the monsoon climate of Sakhalin. To assess the most productive variety, the values of each character were presented as percentage of the maximum for each indicator. Knowing the total values of characters under investigation made it possible to choose the best va-rieties, from authors` point of view, to grow in the household gardens in the monsoon climate of Sakhalin: from the Pavlovsk Experimental Station of Vavilov Institute of Plant Industry – Leningradsky giant (506.4%), Berel (432.9%) and Viola (423.4%).

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