scholarly journals Statistics of Binary Stars: Semi-Major Axes

1976 ◽  
Vol 73 ◽  
pp. 369-379
Author(s):  
V. Trimble ◽  
C. Cheung
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Major Axis ◽  
Small Mass ◽  
Close Binaries ◽  
Mass Ratio ◽  
Orbital Elements ◽  
Semi Major Axis ◽  
Mass Ratios ◽  
Show Evidence

We have examined the distribution of the semi-major axes of the binary systems in the Sixth Catalogue of the Orbital Elements of Spectroscopic Binary Systems (and its extensions) and the correlation of semi-major axis with other properties of the systems. The total distribution has a single peak near asini=107km. Evolved systems have wider separations and smaller mass ratios than unevolved systems. Among each type separately, the distribution of mass ratios is bimodal and small mass ratio is correlated with large separation. These data appear to show evidence of two mechanisms of binary system formation and of the process of mass transfer in close binaries.

scholarly journals Orbital Elements of MACHO Project Eclipsing Binary Stars

2005 ◽  
Vol 13 ◽  
pp. 467-467
Author(s):  
Charles Alcock
Keyword(s):  
Binary Stars ◽  
Large Scale ◽  
Major Axis ◽  
Orbital Elements ◽  
Semi Major Axis ◽  
Eclipsing Binary ◽  
Eclipsing Binary Stars ◽  
Large Numbers ◽  
Short Period ◽  
Velocity Information

Large scale photometric surveys can deliver very large numbers of eclipsing binary stars. It is not presently possible to obtain radial velocity information for more than a small fraction of these. We have made some progress in the estimation of the statistical distributions of orbital elements (including semi-major axis and eccentricity) in the MACHO Project catalog of eclipsing binary stars. We see the well-known tendency to circularization in short period orbits and also detect late tidal circularization during the giant phase. The extension of these techniques to newer surveys will also be discussed.

scholarly journals Planet Formation in Close Binaries

2014 ◽  
Vol 9 (S310) ◽  
pp. 216-217
Author(s):  
Hannah Jang-Condell
Keyword(s):  
Binary Stars ◽  
Planet Formation ◽  
Semimajor Axis ◽  
Major Axis ◽  
Close Binary ◽  
Close Binaries ◽  
Semi Major Axis ◽  
Primary Star ◽  
Mass Eccentricity

AbstractSeveral exoplanets have been discovered in close binaries (a < 30 AU) to date.The fact that planets can form in these dynamically challenging environments says that planet formation must be a robust process. Disks in these systems should be tidally truncated to within a few AU, so if they form in situ, the efficiency of planet formation must be high. While the dynamical capture of planets is also a possibility, the probability of these interactions is low, so in situ formation is the more plausible explanation. I examine the truncation of protoplanetary disks in close binary stars, studying how the disk mass is affected as it evolves from higher accretion rates to lower rates. In the gamma Cephei system, a protoplanetary disk around the primary star should be truncated to within a few AU, but enough mass still remains for planets to form. However, if the semimajor axis of the binary is too small or its eccentricity is too high, such as in HD 188753, the disk will have too little mass for planet formation to occur. I present a way to characterize the feasibility of planet formation based on binary orbital parameters such as stellar mass, companion mass, eccentricity and semi-major axis. Using this measure, we can quantify the robustness of planet formation in close binaries and better understand the overall efficiency of planet formation in general.

scholarly journals Dynamics of quadruple system Finsen 332 = ADS 11640 = HIP 92027 = WDS 18455+0530

2003 ◽  
pp. 63-68
Author(s):  
Dragomir Olevic ◽  
Zorica Cvetkovic
Keyword(s):  
Spectral Type ◽  
Main Sequence ◽  
Semimajor Axis ◽  
Major Axis ◽  
Double Star ◽  
Close Binaries ◽  
Orbital Elements ◽  
Semi Major Axis ◽  
Multiple Stars ◽  
Quadruple System

In 1829 Struve discovered a double star denoted as STF 2375 AB later on. Its separation was 2". 2. It was noticed by Finsen from the Southern Observatory (Johannesburg) in 1953 that the components A and B are close binaries with separations about 0".15. The motion within this quadruple system - FIN 332 Aa and FIN 332 Bb - has been monitored from that time on. The data about the motion of these close binaries are analyzed by the present authors and the preliminary orbital elements are calculated for each of them. The dynamical parallax from the obtained period and the semi major axis for pair FIN 332 Bb agrees completely with that obtained from the Hipparcos program. In the case of FIN 332 Aa a somewhat higher parallax but within the error limits following from the errors of the period and semimajor axis, is obtained and it agrees with the parallax for FIN 332 Bb. The dynamical masses for the components of both systems are as expected for their spectral type A1V (all of them belong to the Main Sequence and here one uses Angelov?s (1993) relation). According to our results, the motion of both systems takes place approximately in the same plane, confirming thus some general properties already noticed in the case of multiple stars.

scholarly journals Investigation of Possible Abundance Anomalies in Close Binaries of Spectral Types A0-A2 & F5-F6

1968 ◽  
Vol 1 ◽  
pp. 432-436
Author(s):  
Yoji Kondo
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Close Binaries ◽  
National Observatory ◽  
Orbital Elements ◽  
Object A ◽  
Spectroscopic Binary ◽  
Standard Spectrum ◽  
Abundance Anomalies

This investigation was originally conceived as a follow-up on a work by Abt (1965), in which he finds the close binaries, with periods of about 1–100 days, and with spectral types of about A4-F2 (IV-V), to be all Am stars. The stars to be observed were chosen from the ‘Fifth Catalogue of the Orbital Elements of Spectroscopic Binary Stars’ (Moore and Neubauer, 1948). The criteria in making the selection were that the spectral types are A0-A2 and F5-F6 (IV-V) and that the periods are between about 1–100 days.Spectra of 11 binary systems were obtained at the Coude focus of the 84-inch reflector of the Kitt Peak National Observatory during three nights in May 1967. In addition to the binary stars, 5 standard spectrum stars, i.e. α Lyr (A0V), θ Leo (A2V), σ Boo (F2 V), ι Peg (F5 V) and 110 Her (F6 V), were observed to provide comparisons. The dispersion used was 13·5 Å/mm. Typically 2 or 3 spectra were obtained for each object. A spot densitometer was employed to furnish calibrations for the plates.

scholarly journals Fission Candidates Among Detached Close Binaries

1984 ◽  
Vol 80 ◽  
pp. 75-83
Author(s):  
H.-A. Ott
Keyword(s):  
Main Sequence ◽  
Small Mass ◽  
Close Binaries ◽  
Mass Ratio ◽  
Model Calculations ◽  
Mass Ratios ◽  
Low Mass ◽  
Statistical Trends ◽  
Momentum Relation

AbstractA comparison between results of model calculations and observed properties of close, but detached low mass binaries with Main Sequence primaries shows statistical trends, which seem to support fission origin for some of these objects: the mass-momentum relation, the relation between mass ratio and separation and the relation between mass ratio and synchronisation speak in favour of close initial separations and small mass ratios of the components.

scholarly journals γ DOR: A PULSATING COMPONENT OF KIC 8043961 IN A STELLAR TRIPLE SYSTEM

2020 ◽  
Vol 56 (2) ◽  
pp. 179-191
Author(s):  
C. Kamil ◽  
H. A. Dal ◽  
O. Özdarcan ◽  
E. Yoldaş
Keyword(s):  
Major Axis ◽  
Primary Component ◽  
Mass Ratio ◽  
Third Body ◽  
Semi Major Axis ◽  
Orbital Inclination ◽  
The Third ◽  
New Findings ◽  
Effective Temperatures ◽  
Orbit Model

We present new findings about KIC 8043961. We find the effective temperatures of the components as 6900 ± 200 K for the primary, and 6598 ± 200 K for the secondary, while the logarithm of the surface gravities are found to be 4.06 cm s-2 and 3.77 cm s-2, respectively. Combination of the light curve with the spectroscopic orbit model results leads to a mass ratio of 1.09 ± 0.07 with an orbital inclination of 73.71 ± 0.14 and a semi-major axis of 8.05 ± 0.22 R⨀ . Masses of the primary and secondary components are calculated as 1.379 ± 0.109 M⨀ and 1.513 ± 0.181 M⨀, while the radii are found to be 1.806 ± 0.084 R⨀ and 2.611 ± 0.059 R⨀. In addition, we obtain a considerable light contribution (≈0.54%) of a third body. We compute a possible mass for the third body as 0.778 ± 0.002 M⨀. We find that the primary component exhibits γ Dor type pulsations with 137 frequencies.

scholarly journals IUE Observations of the Two Peculiar Binary Systems Beta Lyrae and Upsilon Sagittarii

1980 ◽  
Vol 88 ◽  
pp. 271-286 ◽  
Author(s):  
Margherita Hack ◽  
Umberto Flora ◽  
Paolo Santin
Keyword(s):  
Mass Transfer ◽  
Mass Loss ◽  
Radial Velocity ◽  
Effective Temperature ◽  
Binary Systems ◽  
Close Binaries ◽  
Infrared Excess ◽  
Show Evidence ◽  
The Common ◽  
Ultraviolet Observations

The common peculiarities of these two systems are: a) the companion is a massive object (probably m2≥10) whose spectrum is not observable; b) both systems show evidence, though in different degrees, of mass-transfer and mass-loss; c) both present, in different degrees, hydrogen deficiency; d) ultraviolet observations have shown, in both cases, the presence of lines of highly ionized elements like N V, C IV, Si IV, probably formed in an extended envelope because they do not show orbital radial velocity shifts, and cannot be explained by the effective temperature of the star whose spectrum we observe. The latter property seems to be common to several close binaries, as shown by the ultraviolet observations with IUE by Plavec and Koch (1979); e) both systems present infrared excess, suggesting the presence of an extended envelope (Gehrz et al. 1974; Lee and Nariai, 1967; Humphreys and Ney, 1974; Treffers et al. 1976).

scholarly journals The orbital evolution of meteor streams at the 2/1 resonance with Jupiter

1985 ◽  
Vol 83 ◽  
pp. 179-180
Author(s):  
Cl. Froeschlé
Keyword(s):  
Major Axis ◽  
Orbital Evolution ◽  
The Sun ◽  
Orbital Elements ◽  
Meteor Stream ◽  
Semi Major Axis ◽  
Meteor Streams ◽  
Gravitational Forces ◽  
Resonant Effect

We investigated the orbital evolution of Quadrantid-like meteor streams situated in the vicinity of the 2/1 resonance with Jupiter. For the starting orbital elements we took the values of the orbital elements of the Quadrantid meteor stream except for the semi-major axis which was varied between a = 3.22 and a = 3.34 AU. We considered these meteor streams as a ring and we investigated the resonant effect on the dispersion of this ring over a period of 13 000 years. Only gravitational forces due to the Sun and due to Jupiter were taken into account.

42. Close Binary Stars (Etoiles Binaires Serrees)

1988 ◽  
Vol 20 (01) ◽  
pp. 569-594
Author(s):  
J. Smak ◽  
R.H. Koch ◽  
K.D. Abhyankar ◽  
J. Andersen ◽  
A.H. Batten ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Stellar Winds ◽  
Space Instruments ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Astronomy And Astrophysics

During the XlXth General Assembly of the IAU in Delhi the number of members of Cotrmission 42 increased to 260. This simply reflects the growing interest and importance of our field. Growing is not only the number of astronomers involved in research on CBS but also the number of papers resulting from that activity. As an example one can quote the numbers of papers listed during the last few years in Sections 117 (Close Binaries), 119 (Eelipsing Binaries), and 120 (Spectroscopic Binaries) of theAstronomy and Astrophysics Abstracts:705(1982), 775(1983), 836(1984), 1080(1985), and 911(1986); note that many additional references could be added to these numbers from other sections. Naturally, such numbers alone do not reflect the quality and even less so the position and significance of the CBS field. Here one could perhaps mention an impressive record of successful research proposals involving requests for the observing time on large, ground based telescopes and on space instruments. Indeed, in spite of a very strong competition from other fields, programs involving CBS are usually placed very high on the priority lists (cf. Sections 2D and 2E). Obviously, the close binary systems, their evolution, and the physical processes which occur in them (accretion, stellar winds, nuclear burning, etc) appear interesting and important not only to those who are involved in their studies but also to astronomers from other fields.

scholarly journals Slowly, slowly in the wind

2019 ◽  
Vol 626 ◽  
pp. A68 ◽  
Author(s):  
M. I. Saladino ◽  
O. R. Pols ◽  
C. Abate
Keyword(s):  
Angular Momentum ◽  
Wind Velocity ◽  
Binary Systems ◽  
Asymptotic Giant Branch ◽  
Mass Ratio ◽  
Momentum Loss ◽  
Angular Momentum Loss ◽  
Mass Ratios ◽  
Type Ia ◽  
Particle Hydrodynamics

Wind mass transfer in binary systems with asymptotic giant branch (AGB) donor stars plays a fundamental role in the formation of a variety of objects, including barium stars and carbon-enhanced metal-poor (CEMP) stars. In an attempt to better understand the properties of these systems, we carry out a comprehensive set of smoothed-particle hydrodynamics (SPH) simulations of wind-losing AGB stars in binaries for a variety of binary mass ratios, orbital separations, initial wind velocities, and rotation rates of the donor star. The initial parameters of the simulated systems are chosen to match the expected progenitors of CEMP stars. We find that the strength of interaction between the wind and the stars depends on the ratio of wind velocity to orbital velocity (v∞/vorb) and on the binary mass ratio. Strong interaction occurs for close systems and comparable mass ratios, and gives rise to a complex morphology of the outflow and substantial angular-momentum loss, which leads to a shrinking of the orbit. As the orbital separation increases and the mass of the companion star decreases, the morphology of the outflow and the angular-momentum loss become more similar to the spherically symmetric wind case. We also explore the effects of tidal interaction and find that for orbital separations up to 7−10 AU, depending on mass ratio, spin-orbit coupling of the donor star occurs at some point during the AGB phase. If the initial wind velocity is relatively low, we find that corotation of the donor star results in a modified outflow morphology that resembles wind Roche-lobe overflow. In this case the mass-accretion efficiency and angular-momentum loss differ from those found for a non-rotating donor. Finally, we provide relations for the mass-accretion efficiency and angular-momentum loss as a function of v∞/vorb and the binary mass ratio that can be easily implemented in a population synthesis code to study populations of barium stars, CEMP stars, and other products of interaction in AGB binaries, such as cataclysmic binaries and type Ia supernovae.

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