The study of short orbital period of delta scuti pulsating variable stars

2019 ◽  
Vol 15 (S356) ◽  
pp. 407-407
Author(s):  
Abduselam Mohammed
Keyword(s):  
Time Delay ◽  
Orbital Period ◽  
Binary Stars ◽  
Arrival Time ◽  
Periodic Variation ◽  
Variable Stars ◽  
Orbital Elements ◽  
Pulsating Stars ◽  
Delta Scuti ◽  
Arrival Time Delay

AbstractAs a pulsating star moves in its binary orbit, the path length of the light between us and the star varies, leading to the periodic variation in the arrival time of the signal from the star to us (earth). With the consideration of pulsators light arrival time delay effects several new methods which allows using Kepler photometric data (light curves) alone to find binary stars have been recently developed. Among these modern techniques we used binarogram method and we identified that several δSct pulsating stars have companions. The application of these method on detecting long periods(i.e. longer than about 50 d) δSct pulsating stars is not new, but the uniqueness of this study is we verified that it is also applicable to detect and determine the orbital elements of short periods (i.e short orbital period) δSct pulsating stars. With this investigation, we identified the possible way to overcome effects of fictious peaks, even, on the maximum peaks helpful to verify weather the star has companion or not depend up on the existence of the time-delay. Then, we applied the technique on known binary stars and their orbital elements are previously published. Finally, we identified some new short orbital period δSct pulsating stars and obtained their orbital frequency and period with the same procedures. Because of with our attempts we succeeded and verified the applicability of the method (the Binarogram method) on these stars (i.e short orbital period) for the first time, we expect that our present study will play a great role for similar study and to improve our binary statistics.

TIME VARIATION OF THE GRAVITATIONAL CONSTANT AND SECULAR EVOLUTION OF THE ORBIT OF BINARY STARS

2009 ◽  
Vol 18 (08) ◽  
pp. 1243-1256 ◽  
Author(s):  
LIN-SEN LI
Keyword(s):  
Secular Variation ◽  
Time Variation ◽  
Binary Stars ◽  
Gravitational Constant ◽  
Semimajor Axis ◽  
Periodic Variation ◽  
Numerical Results ◽  
Orbital Elements ◽  
Secular Evolution ◽  
Theoretical Results

The author of this paper examines the influence of time variation of the gravitational constant on the evolution of the orbital elements of binary stars. The theoretical results show that the semimajor axis, eccentricity and mean longitude exhibit periodic, secular and mixed periodic variation, but the longitude of the periastron exists in periodic and mixed periodic variation, but not secular variation. The inclination and ascending node exhibit no variation. In addition, the limits of the secular evolution of the orbit of six binary stars due to time variation of the gravitational constant are estimated. The numerical results are given. The theoretical results are discussed and conclusions drawn.

Deviation of the arrival-time delay of pulses for the Crab pulsar from a quadratic frequency region

2008 ◽  
Vol 52 (11) ◽  
pp. 910-916 ◽  
Author(s):  
A. D. Kuz’min ◽  
B. Ya. Losovskii ◽  
S. V. Logvinenko ◽  
I. I. Litvinov
Keyword(s):  
Time Delay ◽  
Arrival Time ◽  
Frequency Region ◽  
Crab Pulsar ◽  
Arrival Time Delay

scholarly journals Punctuality of Intercity Trains and Passengers' Perspective towards Arrival Time Delay

2013 ◽  
Vol 11 (9) ◽  
pp. 1998-2002
Author(s):  
Nur Sabahiah Abdul Sukor ◽  
Moganraj Subramaniam ◽  
Mohd Idrus Mohd Masirin
Keyword(s):  
Time Delay ◽  
Arrival Time ◽  
Arrival Time Delay

scholarly journals Combining neutrino experimental light-curves for pointing to the next galactic core-collapse supernova

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
A. Coleiro ◽  
M. Colomer Molla ◽  
D. Dornic ◽  
M. Lincetto ◽  
V. Kulikovskiy
Keyword(s):  
Time Delay ◽  
Arrival Time ◽  
Light Curves ◽  
Core Collapse ◽  
Chi Square ◽  
Neutrino Detectors ◽  
Core Collapse Supernova ◽  
Arrival Time Delay ◽  
Detector Simulation

AbstractThe multi-messenger observation of the next galactic core-collapse supernova will shed light on the different physical processes involved in these energetic explosions. Good timing and pointing capabilities of neutrino detectors would help in the search for an electromagnetic or gravitational-wave counterparts. An approach for the determination of the arrival time delay of the neutrino signal at different experiments using a direct detected neutrino light-curve matching is discussed. A simplified supernova model and detector simulation are used for its application. The arrival time delay and its uncertainty between two neutrino detectors are estimated with chi-square and cross-correlation methods. The direct comparison of the detected light-curves offers the advantage to be model-independent. Millisecond time resolution on the arrival time delay at two different detectors is needed. Using the computed time delay between different combinations of currently operational and future detectors, a triangulation method is used to infer the supernova localisation in the sky. The combination of IceCube, Hyper-Kamiokande, JUNO and KM3NeT/ARCA provides a 90% confidence area of $$140\pm 20\,\hbox {deg}^2$$ 140 ± 20 deg 2 . These low-latency analysis methods can be implemented in the SNEWS alert system.

RSCVn Stars in the Southern Hemisphere

1979 ◽  
Vol 46 ◽  
pp. 371-384 ◽  
Author(s):  
J.B. Hearnshaw
Keyword(s):  
Light Curve ◽  
Southern Hemisphere ◽  
Orbital Period ◽  
Binary Stars ◽  
Small Amplitude ◽  
Light Variation ◽  
Orbital Phase

RSCVn stars are fully detached binary stars which show intrinsic small amplitude (up to 0.3 amplitude peak-to-peak) light variations, as well as, in most of the known cases, eclipses. The spectra are F to G, IV to V for the hotter component and usually KOIV for the cooler. They are also characterised by abnormally strong H and K emission from the cooler star, or, occasionally, from both components. The orbital and light curve periods are in the range 1 day to 2 weeks. An interesting feature is the migration of the light variations to earlier orbital phase, as the light variation period is shorter than the orbital period by a few parts in 10+4to a few parts in 10+3.

scholarly journals Inverse tides in pulsating binary stars

2020 ◽  
Vol 501 (1) ◽  
pp. 483-490
Author(s):  
Jim Fuller
Keyword(s):  
Binary Stars ◽  
Close Binary ◽  
Close Binaries ◽  
Spin Orbit ◽  
Misalignment Angle ◽  
Stellar Rotation ◽  
Transfer Energy ◽  
Pulsating Stars ◽  
Mode Amplitude ◽  
Rotation Periods

ABSTRACT In close binary stars, the tidal excitation of pulsations typically dissipates energy, causing the system to evolve towards a circular orbit with aligned and synchronized stellar spins. However, for stars with self-excited pulsations, we demonstrate that tidal interaction with unstable pulsation modes can transfer energy in the opposite direction, forcing the spins of the stars away from synchronicity, and potentially pumping the eccentricity and spin–orbit misalignment angle. This ‘inverse’ tidal process only occurs when the tidally forced mode amplitude is comparable to the mode’s saturation amplitude, and it is thus most likely to occur in main-sequence gravity mode pulsators with orbital periods of a few days. We examine the long-term evolution of inverse tidal action, finding the stellar rotation rate can potentially be driven to a very large or very small value, while maintaining a large spin–orbit misalignment angle. Several recent asteroseismic analyses of pulsating stars in close binaries have revealed extremely slow core rotation periods, which we attribute to the action of inverse tides.

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