scholarly journals Infinity – A New Program for Modeling Binary Systems

2011 ◽  
Vol 7 (S282) ◽  
pp. 305-306
Author(s):  
Cséki Attila ◽  
Olivera Latković
Keyword(s):  
Inverse Problem ◽  
Radial Velocity ◽  
Accretion Disks ◽  
Binary Systems ◽  
Object Oriented ◽  
Light Curves ◽  
Great Care ◽  
Work In Progress ◽  
Stage Of Development ◽  
Limb Darkening

AbstractInfinity is a new program for modeling binary systems. The model is based on Roche geometry with asynchronous rotation, including an assortment of effects like gravity and limb darkening, mutual irradiation, bright and dark spots and so on. However, Infinity brings innovations in the modeling of accretion disks, and introduces the modeling of radial and non-radial oscillations on one or both components of the system.At this stage of development, Infinity can produce light curves, spectra and radial velocity curves; solving the inverse problem is still a work in progress. In terms of programming, Infinity is being developed in the object-oriented language C#, and great care is taken to produce readable, easily extensible and verifiable code. Infinity is fully optimized to take advantage of modern multi-core CPUs, and the code is thoroughly covered with unit-tests. We expect to make a public release during 2012.

scholarly journals Homogeneously derived transit timings for 17 exoplanets and reassessed TTV trends for WASP-12 and WASP-4

2019 ◽  
Vol 490 (1) ◽  
pp. 1294-1312 ◽  
Author(s):  
R V Baluev ◽  
E N Sokov ◽  
H R A Jones ◽  
V Sh Shaidulin ◽  
I A Sokova ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Photometric Data ◽  
Light Curves ◽  
Radial Acceleration ◽  
High Significance ◽  
Self Consistent ◽  
Doppler Data ◽  
Photometric Measurements ◽  
Limb Darkening ◽  
Rule Out

ABSTRACT We homogeneously analyse ∼3.2 × 105 photometric measurements for ∼1100 transit light curves belonging to 17 exoplanet hosts. The photometric data cover 16 years (2004–2019) and include amateur and professional observations. Old archival light curves were reprocessed using up-to-date exoplanetary parameters and empirically debiased limb-darkening models. We also derive self-consistent transit and radial-velocity fits for 13 targets. We confirm the non-linear transit timing variation (TTV) trend in the WASP-12 data at a high significance, and with a consistent magnitude. However, Doppler data reveal hints of a radial acceleration of about −7.5 ± 2.2 m s−1 yr−1, indicating the presence of unseen distant companions, and suggesting that roughly 10 per cent of the observed TTV was induced via the light-travel (or Roemer) effect. For WASP-4, a similar TTV trend suspected after the recent TESS observations appears controversial and model dependent. It is not supported by our homogeneous TTV sample, including 10 ground-based EXPANSION light curves obtained in 2018 simultaneously with TESS. Even if the TTV trend itself does exist in WASP-4, its magnitude and tidal nature are uncertain. Doppler data cannot entirely rule out the Roemer effect induced by possible distant companions.

scholarly journals Disk Instabilities in the Black Hole Binaries

1996 ◽  
Vol 158 ◽  
pp. 135-138 ◽  
Author(s):  
J. K. Cannizzo
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Time Constant ◽  
Accretion Disks ◽  
Binary Systems ◽  
Recent Progress ◽  
Light Curves ◽  
X Ray ◽  
Black Hole Binaries ◽  
Exponential Character

I will briefly review recent progress in our understanding of the global propagation of accretion disk instabilities operating in interacting binary systems in which the accreting star is a ~ 10 M⊙ black hole. A detailed discussion of this work can be found in Cannizzo, Chen & Livio (1995).The X-ray light curves of the brightest and best studied X-ray novae – systems such as A0620–00, GS2000+25, GS1124–68, and GRO J0422+32 – are notable in two respects: the rise times are fast (a few days) and the decays have an exponential character, where the e–folding time constant is about 30 to 40 d (Mineshige, Yamasaki, & Ishizaka 1993, hereafter MYI). It is noteworthy that outbursts in dwarf novae also decay exponentially, with the time constant being about a factor of 10 shorter. In this contribution I will discuss the constraints on the physics of accretion disks which the (observed) exponential decay enables us to make.

scholarly journals The Transit and Light Curve Modeller

2020 ◽  
Vol 496 (4) ◽  
pp. 4442-4467 ◽  
Author(s):  
Sz Csizmadia
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Binary Systems ◽  
Computer Code ◽  
Physical Description ◽  
First Order ◽  
Relativistic Beaming ◽  
Velocity Drift ◽  
Limb Darkening ◽  
The Impact

ABSTRACT Transit and Light Curve Modeller (TLCM), a computer code with the purpose of analysing photometric time series of transits simultaneously with the out-of-transit light variations and radial velocity curves of transiting/eclipsing binary systems, is presented here. Joint light-curve and radial velocity fits are possible with it. The code is based on the combination of a genetic algorithm and simulated annealing. Binning, beaming, reflection, and ellipsoidal effects are included. Both objects may have their own luminosities and therefore one can use TLCM to analyse the eclipses of both exoplanet and well-detached binary systems. A simplified Rossiter–McLaughlin effect is included in the radial velocity fit, and drifts and offsets of different instruments can also be fitted. The impact of poorly known limb darkening on the Rossiter–McLaughlin effect is shortly studied. TLCM is able to manage red-noise effects via wavelet analysis. It is also possible to add parabolic or user-defined baselines and features to the code. I also predict that light variations due to beaming in some systems exhibiting radial velocity drift should be observed by, e.g. PLATO. The fit of the beaming effect is improved by invoking a physical description of the ellipsoidal effects, which has an impact on the modelling of the relativistic beaming; I also point out the difficulties that are stemming from the fact that beaming and first-order reflection effects have the same form of time dependence. Recipe is given, which describes how to analyse grazing transit events. The code is freely available.

scholarly journals Unexpected Short-period Variability in Dwarf Carbon Stars from the Zwicky Transient Facility

2021 ◽  
Vol 922 (1) ◽  
pp. 33
Author(s):  
Benjamin R. Roulston ◽  
Paul J. Green ◽  
Silvia Toonen ◽  
J. J. Hermes
Keyword(s):  
Mass Transfer ◽  
Radial Velocity ◽  
Binary Systems ◽  
Roche Lobe ◽  
Light Curves ◽  
Common Envelope ◽  
Short Period ◽  
Velocity Variations ◽  
Rich Material

Abstract Dwarf carbon (dC) stars, main-sequence stars showing carbon molecular bands, are enriched by mass transfer from a previous asymptotic-giant-branch (AGB) companion, which has since evolved to a white dwarf. While previous studies have found radial-velocity variations for large samples of dCs, there are still relatively few dC orbital periods in the literature and no dC eclipsing binaries have yet been found. Here, we analyze photometric light curves from DR5 of the Zwicky Transient Facility for a sample of 944 dC stars. From these light curves, we identify 34 periodically variable dC stars. Remarkably, of the periodic dCs, 82% have periods less than two days. We also provide spectroscopic follow-up for four of these periodic systems, measuring radial velocity variations in three of them. Short-period dCs are almost certainly post-common-envelope binary systems, because the periodicity is most likely related to the orbital period, with tidally locked rotation and photometric modulation on the dC either from spots or from ellipsoidal variations. We discuss evolutionary scenarios that these binaries may have taken to accrete sufficient C-rich material while avoiding truncation of the thermally pulsing AGB phase needed to provide such material in the first place. We compare these dCs to common-envelope models to show that dC stars probably cannot accrete enough C-rich material during the common-envelope phase, suggesting another mechanism like wind-Roche lobe overflow is necessary. The periodic dCs in this paper represent a prime sample for spectroscopic follow-up and for comparison to future models of wind-Roche lobe overflow mass transfer.

scholarly journals Light Curves Analysis and Period Study of Two Eclipsing Binaries UZ Lyr and BR Cyg

2021 ◽  
Author(s):  
Kazem Yoosefi Roobiat ◽  
Reza Pazhouhesh
Keyword(s):  
Mass Transfer ◽  
Radial Velocity ◽  
Orbital Period ◽  
Binary Systems ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Secondary Component ◽  
Physical Parameters ◽  
Time Effects ◽  
First Time

Abstract Two eclipsing binary systems UZ Lyr and BR Cyg are the semi-detached types whose secondary component fill its Roche lobe. Although radial velocity and light curves of these systems have already been investigated separately, both radial velocity and light curves of them are analyzed simultaneously for the first time in the present study . Also, the orbital period changes of these systems are studied. Our results show that the mass transfer between components have negligible effects on the orbital period changes of these systems, but two light-time effects are the reasons of the periodic behavior of the O-C curve for UZ Lyr. We could not remark more information about orbital period changes for BR Cyg, but we find a new orbital period for it. By radial velocity and light curves analysis we find a clod spot on the secondary components of BR Cyg. The new geometrical and physical parameters of both systems are obtained and their positions on H-R diagram demonstrated.

scholarly journals BEER analysis of Kepler and CoRoT light curves – V. eBEER: extension of the algorithm to eccentric binaries

2020 ◽  
Vol 497 (4) ◽  
pp. 4884-4895
Author(s):  
M Engel ◽  
S Faigler ◽  
S Shahaf ◽  
T Mazeh
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Binary Systems ◽  
Light Curves ◽  
Harmonic Series ◽  
Eclipsing Binary ◽  
Fast Processing

ABSTRACT We present an extension of the BEER model for eccentric binaries – eBEER, approximating the BEaming, Ellipsoidal, and Reflection effects by harmonic series of the Keplerian elements of their orbit. As such, it can be a tool for fast processing of light curves for detecting non-eclipsing eccentric binary systems. To validate the applicability of the eccentric model and its approximations, we applied eBEER to the Kepler light curves, identified a sample of bright non-eclipsing binary candidates, and followed three of them with the Wise observatory eShel spectrograph. After confirming the three systems are indeed radial velocity (RV) binaries, we fitted the light curves and the RV data with PHOEBE, a detailed numerical light curve and RV model, and showed that the PHOEBE derived parameters are similar to those obtained by the eBEER approximation.

Quasi-Periodic Oscillations in Dwarf Novae

1979 ◽  
Vol 46 ◽  
pp. 77-88
Author(s):  
Edward L. Robinson
Keyword(s):  
Binary Systems ◽  
Outer Edge ◽  
Light Curves ◽  
Close Binary ◽  
Bright Spot ◽  
Dwarf Novae ◽  
Periodic Oscillations ◽  
High Frequencies ◽  
Short Period ◽  
Typical Time

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.

scholarly journals The Impact of Gaia and LSST on Binaries and Exoplanets

2011 ◽  
Vol 7 (S282) ◽  
pp. 33-40
Author(s):  
L. Eyer ◽  
P. Dubath ◽  
N. Mowlavi ◽  
P. North ◽  
A. Triaud ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Large Scale ◽  
Binary Systems ◽  
New Era ◽  
The Subject ◽  
The Impact

AbstractTwo upcoming large scale surveys, the ESA Gaia and LSST projects, will bring a new era in astronomy. The number of binary systems that will be observed and detected by these projects is enormous, estimations range from millions for Gaia to several tens of millions for LSST. We review some tools that should be developed and also what can be gained from these missions on the subject of binaries and exoplanets from the astrometry, photometry, radial velocity and their alert systems.

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