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 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.

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 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.

A Radial Velocity and Light Curve Study of Pulsations and Binarity in Proto-Planetary Nebulae

2015 ◽  
Vol 71-72 ◽  
pp. 127-128
Author(s):  
B.J. Hrivnak ◽  
W. Lu ◽  
G. Van de Steene ◽  
H. Van Winckel ◽  
J. Sperauskas ◽  
...  
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Planetary Nebulae

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

scholarly journals Exoplanet mass estimation for a sample of targets for the Ariel mission

2021 ◽  
Author(s):  
J. R. Barnes ◽  
C. A. Haswell
Keyword(s):  
Radial Velocity ◽  
Input Parameter ◽  
Noise Sources ◽  
Time Commitment ◽  
Low Mass ◽  
Time Required ◽  
Fixed Input ◽  
The Impact ◽  
Quadrature Sampling

AbstractAriel’s ambitious goal to survey a quarter of known exoplanets will transform our knowledge of planetary atmospheres. Masses measured directly with the radial velocity technique are essential for well determined planetary bulk properties. Radial velocity masses will provide important checks of masses derived from atmospheric fits or alternatively can be treated as a fixed input parameter to reduce possible degeneracies in atmospheric retrievals. We quantify the impact of stellar activity on planet mass recovery for the Ariel mission sample using Sun-like spot models scaled for active stars combined with other noise sources. Planets with necessarily well-determined ephemerides will be selected for characterisation with Ariel. With this prior requirement, we simulate the derived planet mass precision as a function of the number of observations for a prospective sample of Ariel targets. We find that quadrature sampling can significantly reduce the time commitment required for follow-up RVs, and is most effective when the planetary RV signature is larger than the RV noise. For a typical radial velocity instrument operating on a 4 m class telescope and achieving 1 m s−1 precision, between ~17% and ~ 37% of the time commitment is spent on the 7% of planets with mass Mp < 10 M⊕. In many low activity cases, the time required is limited by asteroseismic and photon noise. For low mass or faint systems, we can recover masses with the same precision up to ~3 times more quickly with an instrumental precision of ~10 cm s−1.

Optimal Capacitors Placement of Distribution Systems Using 2nd Order Power Loss Sensitivity Analysis and Hierarchical Clustering

2014 ◽  
Vol 986-987 ◽  
pp. 377-382 ◽  
Author(s):  
Hui Min Gao ◽  
Jian Min Zhang ◽  
Chen Xi Wu
Keyword(s):  
Sensitivity Analysis ◽  
Hierarchical Clustering ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Systems ◽  
Reactive Power ◽  
Digital Simulation ◽  
Second Order ◽  
First Order ◽  
The Impact

Heuristic methods by first order sensitivity analysis are often used to determine location of capacitors of distribution power system. The selected nodes by first order sensitivity analysis often have virtual high by first order sensitivities, which could not obtain the optimal results. This paper presents an effective method to optimally determine the location and capacities of capacitors of distribution systems, based on an innovative approach by the second order sensitivity analysis and hierarchical clustering. The approach determines the location by the second order sensitivity analysis. Comparing with the traditional method, the new method considers the nonlinear factor of power flow equation and the impact of the latter selected compensation nodes on the previously selected compensation location. This method is tested on a 28-bus distribution system. Digital simulation results show that the reactive power optimization plan with the proposed method is more economic while maintaining the same level of effectiveness.

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