scholarly journals A VLT/FLAMES survey for massive binaries in Westerlund 1. VIII. Binary systems and orbital parameters

2021 ◽  
Author(s):  
B Ritchie ◽  
J Clark ◽  
I Negueruela ◽  
F Najarro
Keyword(s):  
Binary Systems ◽  
Orbital Parameters

scholarly journals Asteroseismic search for invisible binary companions

2015 ◽  
Vol 11 (A29B) ◽  
pp. 642-647
Author(s):  
Hiromoto Shibahashi ◽  
Simon J. Murphy ◽  
Donald W. Kurtz
Keyword(s):  
Radial Velocity ◽  
Frequency Modulation ◽  
Binary Systems ◽  
Binary Star ◽  
Orbital Parameters ◽  
Pulsating Stars ◽  
Kepler Mission ◽  
Orbital Frequency ◽  
Long Time ◽  
The Fourier Transform

AbstractContinuous and precise space-based photometry has made it possible to measure the orbital frequency modulation of pulsating stars in binary systems with extremely high precision over long time spans. We present the phase modulation (PM) method for finding binaries among pulsating stars. We demonstrate how the orbital elements of a pulsating binary star can be obtained analytically from photometry alone, without spectroscopic radial velocity measurement. Frequency modulation (FM) caused by binary orbital motion also manifests itself in the Fourier transform, as a multiplet with equal spacing of the orbital frequency. The orbital parameters can also be extracted by analysing the amplitudes and phases of the peaks in these multiplets. We derive analytically the theoretical relations between the multiplet properties and the orbital parameters, and present a method for determining these parameters, including the eccentricity and the argument of periapsis. This, too, is achievable with the photometry alone, without spectroscopic radial velocity measurements. We apply these two methods to Kepler mission data and demonstrate that the results are in good agreement with each other. These methods are used to search for invisible binary companions, including planets and invisible massive objects such as neutron stars and stellar-mass black holes.

scholarly journals Finding binaries from phase modulation of pulsating stars with Kepler – VI. Orbits for 10 new binaries with mischaracterized primaries

2020 ◽  
Vol 493 (4) ◽  
pp. 5382-5388
Author(s):  
Simon J Murphy ◽  
Nicholas H Barbara ◽  
Daniel Hey ◽  
Timothy R Bedding ◽  
Ben D Fulcher
Keyword(s):  
Phase Modulation ◽  
White Dwarfs ◽  
Binary Systems ◽  
Main Sequence ◽  
Classification Algorithm ◽  
Orbital Parameters ◽  
Pulsating Stars ◽  
Stellar Properties ◽  
Scuti Stars ◽  
Δ Scuti Stars

ABSTRACT Measuring phase modulation in pulsating stars has proven to be a highly successful way of finding binary systems. The class of pulsating main-sequence A and F variables, known as δ Scuti stars consists of particularly good targets for this, and the Kepler sample of these has been almost fully exploited. However, some Keplerδ Scuti stars have incorrect temperatures in stellar properties catalogues, and were missed in previous analyses. We used an automated pulsation classification algorithm to find 93 new δ Scuti pulsators among tens of thousands of F-type stars, which we then searched for phase modulation attributable to binarity. We discovered 10 new binary systems and calculated their orbital parameters, which we compared with those of binaries previously discovered in the same way. The results suggest that some of the new companions may be white dwarfs.

Massive Binaries in the Magellanic Clouds

2005 ◽  
Vol 13 ◽  
pp. 463-463
Author(s):  
Virpi S. Niemela
Keyword(s):  
Binary Stars ◽  
Present Status ◽  
Binary Systems ◽  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Stellar Winds ◽  
Multiple Systems ◽  
Orbital Parameters

We present results of our ongoing observing program on search and studies of massive stars (O and WR type) in binary systems in our neighbor galaxies, the Magellanic Clouds. Radial velocity orbits are presented for two new binaries, one in the Small Magellanic Cloud and another in the Large Magellanic Cloud, and improved orbits for previously known systems. We compare orbital parameters of selected binaries containing O and WR type components. We also discuss the present status of knowledge for massive binary stars in the Magellanic Clouds and the problems encountered in their orbital studies such as stellar winds the ubiquitous tendency to be born in multiple systems.

scholarly journals Line-Profile Variations on Massive Binary Systems: Determining η Carinae Orbital Parameters

2006 ◽  
Vol 2 (S240) ◽  
pp. 198-201
Author(s):  
D. Falceta-Gonçalves ◽  
Z. Abraham ◽  
V. Jatenco-Pereira
Keyword(s):  
Line Profile ◽  
Binary Systems ◽  
Spectral Lines ◽  
Stream Velocity ◽  
Interaction Zone ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Massive Binary Systems ◽  
Shock Fronts ◽  
Synthetic Line

AbstractWhen the winds of two massive stars orbiting each other collide, an interaction zone is created consisting of two shock fronts at both sides of a contact surface. During the cooling process, elements may recombine generating spectral lines. These lines may be Doppler shifted, as the gas stream flows over the interaction zone. To calculate the stream velocity projected into the line of sight we use a simplified conical geometry for the shock fronts and, to determine the synthetic line profile, we have to sum the amount of emitting gas elements with the same Doppler shifted velocity. We show that the stellar mass loss rates and wind velocities, and the orbital inclination and eccentricity, are the main parameters on this physical process. By comparing observational data to the synthetic line profiles it is possible to determine these parameters. We tested this process to Brey 22 WR binary system, and applied to the enigmatic object of η Carinae.

scholarly journals Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2

2019 ◽  
Vol 623 ◽  
pp. A116 ◽  
Author(s):  
Pierre Kervella ◽  
Alexandre Gallenne ◽  
Nancy Remage Evans ◽  
Laszlo Szabados ◽  
Frédéric Arenou ◽  
...  
Keyword(s):  
Proper Motion ◽  
Binary Systems ◽  
Variable Stars ◽  
Rr Lyrae Stars ◽  
Orbital Parameters ◽  
Rr Lyrae ◽  
Multiple Stars ◽  
Classical Cepheids ◽  
The Mean ◽  
Lyrae Stars

Context. Classical Cepheids (CCs) and RR Lyrae stars (RRLs) are important classes of variable stars used as standard candles to estimate galactic and extragalactic distances. Their multiplicity is imperfectly known, particularly for RRLs. Astoundingly, to date only one RRL has convincingly been demonstrated to be a binary, TU UMa, out of tens of thousands of known RRLs. Aims. Our aim is to detect the binary and multiple stars present in a sample of Milky Way CCs and RRLs. Methods. In the present article, we combine the HIPPARCOS and Gaia DR2 positions to determine the mean proper motion of the targets, and we search for proper motion anomalies (PMa) caused by close-in orbiting companions. Results. We identify 57 CC binaries from PMa out of 254 tested stars and 75 additional candidates, confirming the high binary fraction of these massive stars. For 28 binary CCs, we determine the companion mass by combining their spectroscopic orbital parameters and astrometric PMa. We detect 13 RRLs showing a significant PMa out of 198 tested stars, and 61 additional candidates. Conclusions. We determine that the binary fraction of CCs is likely above 80%, while that of RRLs is at least 7%. The newly detected systems will be useful to improve our understanding of their evolutionary states. The discovery of a significant number of RRLs in binary systems also resolves the long-standing mystery of their extremely low apparent binary fraction.

scholarly journals New distance and depth estimates from observations of eclipsing binaries in the SMC

2008 ◽  
Vol 4 (S256) ◽  
pp. 57-62
Author(s):  
Pierre L. North ◽  
Romain Gauderon ◽  
Frédéric Royer
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Average Error ◽  
Distance Modulus ◽  
Orbital Parameters ◽  
Individual System ◽  
The Mean

AbstractA sample of 33 eclipsing binaries observed in a field of the SMC with FLAMES@VLT is presented. The radial velocity curves obtained, together with existing OGLE light curves, allowed the determination of all stellar and orbital parameters of these binary systems. The mean distance modulus of the observed part of the SMC is 19.05 mag, based on the 26 most reliable systems. Assuming an average error of 0.1 mag on the distance modulus to an individual system, and a gaussian distribution of the distance moduli, we obtain a 2-σ depth of 0.36 mag or 10.6 kpc. Some results on the kinematics of the binary stars and of the H ii gas are also given.

scholarly journals Mass Loss from Contact Binary Systems and their Dynamical Evolution

1980 ◽  
Vol 88 ◽  
pp. 511-515
Author(s):  
Kyoji Nariai
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Total Mass ◽  
Binary Systems ◽  
Dynamical Evolution ◽  
Major Axis ◽  
Semi Major Axis ◽  
Orbital Parameters ◽  
Contact Binary ◽  
Fractional Mass

When there is mass loss from a binary system, the lost mass carries energy and angular momentum out of the system. Therefore, the remaining system must adjust its orbital parameters to the changing values of the total kinematic energy E and the total angular momentum N as the total mass M decreases. The parameters concerned here are : the fractional mass μ, the semi-major axis a, and the eccentricity e.

scholarly journals Two new double-lined spectroscopic binary white dwarfs

2020 ◽  
Vol 493 (2) ◽  
pp. 2805-2816 ◽  
Author(s):  
Mukremin Kilic ◽  
A Bédard ◽  
P Bergeron ◽  
Alekzander Kosakowski
Keyword(s):  
Radial Velocity ◽  
White Dwarf ◽  
White Dwarfs ◽  
Binary Systems ◽  
Mass Ratio ◽  
Orbital Parameters ◽  
Long Period ◽  
Spectroscopic Binary ◽  
Velocity Variations ◽  
Period System

ABSTRACT We present radial velocity observations of four binary white dwarf candidates identified through their overluminosity. We identify two new double-lined spectroscopic binary systems, WD 0311–649 and WD 1606+422, and constrain their orbital parameters. WD 0311–649 is a 17.7 h period system with a mass ratio of 1.44 ± 0.06 and WD 1606+422 is a 20.1 h period system with a mass ratio of 1.33 ± 0.03. An additional object, WD 1447–190, is a 43 h period single-lined white dwarf binary, whereas WD 1418–088 does not show any significant velocity variations over time-scales ranging from minutes to decades. We present an overview of the 14 overluminous white dwarfs that were identified by Bédard et al., and find the fraction of double- and single-lined systems to be both 31 per cent. However, an additional 31 per cent of these overluminous white dwarfs do not show any significant radial velocity variations. We demonstrate that these must be in long-period binaries that may be resolved by Gaia astrometry. We also discuss the overabundance of single low-mass white dwarfs identified in the SPY survey, and suggest that some of those systems are also likely long-period binary systems of more massive white dwarfs.

scholarly journals Solving for the Orbital Elements of Binary Systems using MCMC Simulations.

2013 ◽  
Vol 8 (S299) ◽  
pp. 52-53
Author(s):  
Kyle Mede ◽  
Timothy D. Brandt
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Markov Chain Monte Carlo ◽  
Observational Data ◽  
Confidence Intervals ◽  
Formation Mechanism ◽  
Binary Systems ◽  
Three Dimensional ◽  
Orbital Elements ◽  
Orbital Parameters

AbstractRecent simulation and observational data have been used to investigate the ability of Kozai oscillations to explain the formation of “hot Jupiter” planetary systems. One of the first exoplanets discovered, τ Boo Ab, orbits a star with a binary companion, making it an excellent testbed for this scenario. We have written a three-dimensional Markov Chain Monte Carlo (MCMC) simulator to constrain the orbit of the distant stellar companion τ Boo B, and are currently deriving orbital parameters and confidence intervals. These orbital parameters will confirm or reject Kozai oscillations as a plausible formation mechanism for τ Boo Ab.

scholarly journals Polarimetry of Binary Stars and Exoplanets

2011 ◽  
Vol 7 (S282) ◽  
pp. 173-180
Author(s):  
Karen S. Bjorkman
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Circumstellar Environments ◽  
Exoplanet Systems

AbstractPolarimetry is a useful diagnostic of asymmetries in both circumstellar environments and binary star systems. Its sensitivity to asymmetries in systems means that it can help to uncover details about system orbital parameters, including providing information about the orbital inclination. Polarimetry can probe the circumstellar and/or circumbinary material as well. A number of significant results on binary systems have been produced by polarimetric studies. One might therefore expect that polarimetry could similarly play a useful role in studies of exoplanets, and a number of possible diagnostics for exoplanets have been proposed. However, the application of polarimetry to exoplanet research is only in preliminary stages, and the difficulties with applying the technique to exoplanets are non-trivial. This review will discuss the successes of polarimetry in analyzing binary systems, and consider the possibilities and challenges for extending similar analysis to exoplanet systems.

Sign in / Sign up

Export Citation Format

Share Document