scholarly journals Modified Newtonian Gravity, Wide Binaries and the Tully-Fisher Relation

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 209
Author(s):  
Luis Acedo
Keyword(s):  
Binary Star ◽  
Mass Parameter ◽  
Newtonian Gravity ◽  
Wide Binary ◽  
Asymptotic Constant ◽  
Galactic Clusters ◽  
Klein Gordon ◽  
Fisher Relation ◽  
Dependent Mass ◽  
Near Future

A recent study of a sample of wide binary star systems from the Hipparcos and Gaia catalogues has found clear evidence of a gravitational anomaly of the same kind as that appearing in galaxies and galactic clusters. Instead of a relative orbital velocity decaying as the square root of the separation, ΔV∝r−1/2, it was shown that an asymptotic constant velocity is reached for distances of order 0.1 pc. If confirmed, it would be difficult to accommodate this breakdown of Kepler’s laws within the current dark matter (DM) paradigm because DM does not aggregate in small scales, so there would be very little DM in a 0.1 pc sphere. In this paper, we propose a simple non-Newtonian model of gravity that could explain both the wide binaries anomaly and the anomalous rotation curves of galaxies as codified by the Tully-Fisher relation. The required extra potential can be understood as a Klein-Gordon field with a position-dependent mass parameter. The extra forces behave as 1/r on parsec scales and r on Solar system scales. We show that retrograde anomalous perihelion precessions are predicted for the planets. This could be tested by precision ephemerides in the near future.

scholarly journals Exact Solutions of the Mass-Dependent Klein-Gordon Equation with the Vector Quark-Antiquark Interaction and Harmonic Oscillator Potential

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
M. K. Bahar ◽  
F. Yasuk
Keyword(s):  
Harmonic Oscillator ◽  
Exact Solutions ◽  
Gordon Equation ◽  
Oscillator Potential ◽  
Ansatz Method ◽  
Harmonic Oscillator Potential ◽  
Klein Gordon ◽  
Dependent Mass ◽  
Mass Dependent ◽  
Klein Gordon Equation

Using the asymptotic iteration and wave function ansatz method, we present exact solutions of the Klein-Gordon equation for the quark-antiquark interaction and harmonic oscillator potential in the case of the position-dependent mass.

scholarly journals Statistical Modeling and Analysis of Wide Binary Star Systems

2006 ◽  
Vol 2 (S240) ◽  
pp. 686-689
Author(s):  
K.B. Johnston ◽  
T.D. Oswalt ◽  
D. Valls-Gabaud
Keyword(s):  
Mass Loss ◽  
Main Sequence ◽  
Galactic Disk ◽  
Binary Star ◽  
Wide Binary ◽  
Robust Test ◽  
Modeling And Analysis ◽  
Tidal Interactions ◽  
Wide Pairs ◽  
Binary Separations

AbstractPost-main-sequence (MS) mass loss causes orbital separation amplification in fragile (i.e. common proper motion) binary star systems. Components typically have separations around ∼1000 AU. Such wide pairs experience negligible tidal interactions and mass transfer between companions; thus they evolve as two separate but coeval stars. In this paper we compute the rate of mass loss during the components' lifetimes and attempt to model how it will statistically distort a frequency distribution of fragile binary separations. Understanding this process provides a robust test of current theories of stellar evolution and sets constraints on the dynamics of the Galactic disk.

Klein–Gordon oscillator with position-dependent mass in the rotating cosmic string spacetime

2018 ◽  
Vol 33 (04) ◽  
pp. 1850025 ◽  
Author(s):  
Bing-Qian Wang ◽  
Zheng-Wen Long ◽  
Chao-Yun Long ◽  
Shu-Rui Wu
Keyword(s):  
Magnetic Field ◽  
Cosmic String ◽  
Energy Levels ◽  
Homogeneous Magnetic Field ◽  
Spinless Particle ◽  
Klein Gordon ◽  
Coulomb Type ◽  
Dependent Mass ◽  
String Background ◽  
Position Dependent Mass

A spinless particle coupled covariantly to a uniform magnetic field parallel to the string in the background of the rotating cosmic string is studied. The energy levels of the electrically charged particle subject to the Klein–Gordon oscillator are analyzed. Afterwards, we consider the case of the position-dependent mass and show how these energy levels depend on the parameters in the problem. Remarkably, it shows that for the special case, the Klein–Gordon oscillator coupled covariantly to a homogeneous magnetic field with the position-dependent mass in the rotating cosmic string background has the similar behaviors to the Klein–Gordon equation with a Coulomb-type configuration in a rotating cosmic string background in the presence of an external magnetic field.

scholarly journals APPROXIMATE ℓ-STATE SOLUTIONS TO THE KLEIN–GORDON EQUATION FOR MODIFIED WOODS–SAXON POTENTIAL WITH POSITION DEPENDENT MASS

2009 ◽  
Vol 24 (20n21) ◽  
pp. 3985-3994 ◽  
Author(s):  
ALTUĞ ARDA ◽  
RAMAZAN SEVER
Keyword(s):  
Approximation Scheme ◽  
Gordon Equation ◽  
Saxon Potential ◽  
Radial Part ◽  
Potential Term ◽  
Energy Eigenvalues ◽  
Klein Gordon ◽  
Uvarov Method ◽  
Dependent Mass ◽  
Klein Gordon Equation

The radial part of the Klein–Gordon equation for the generalized Woods–Saxon potential is solved by using the Nikiforov–Uvarov method with spatially dependent mass within the new approximation scheme to the centrifugal potential term. The energy eigenvalues and corresponding normalized eigenfunctions are computed. The solutions in the case of constant mass are also obtained to check out the consistency of our new approximation scheme.

scholarly journals Observational signs of wide binary stars dissolution in Gaia DR2 data

2020 ◽  
pp. 336-340
Author(s):  
С.А. Сапожников ◽  
Д.А. Ковалева
Keyword(s):  
Binary Stars ◽  
Proper Motion ◽  
Binary Star ◽  
Logarithmic Scale ◽  
The Sun ◽  
Numerical Estimation ◽  
Wide Binary ◽  
Random Pairing ◽  
The Common ◽  
Gaia Dr2

По данным Gaia DR2 в радиусе 100 пк от Солнца исследованы двойные звезды с общим собственным движением до расстояния между компонентами 3 пк. Для исключения возможных случайных совпадений смоделирована искусственная выборка случайных пар. Показано, что принятый способ отбора пар с общим собственным движением делает загрязнение выборки случайными совпадениями незначительным даже при больших расстояниях между компонентами; величина такого загрязнения оценена численно. Получено бимодальное распределение по логарифму расстояния между компонентами, демонстрирующее для очень широких пар минимум, связанный с распадом систем, на расстоянии ≈ 0.5 пк, и дальнейший рост, формируемый распавшимися, медленно расходящимися компонентами. Binary and common proper motion stars within 100 pc of the Sun are being investigated using Gaia DR2 data. An artificial random pairs sample is constructed to exclude possible random pairing contamination. Numerical estimation of this contamination shows that the chosen method to select the common proper motion stars yields little contamination even at high separations. In a logarithmic scale the separation distribution appear to have a minimum at ≈ 0.5 pc, most likely related to binary star dissolution, with further increase formed by dissolved, slowly distancing components.

scholarly journals Simultaneous determination of mass parameter and radial marker in Schwarzschild geometry

2021 ◽  
Author(s):  
Victor Varela ◽  
Lorenzo Leal
Keyword(s):  
General Relativity ◽  
Simultaneous Determination ◽  
Euclidean Geometry ◽  
Proper Time ◽  
Mass Parameter ◽  
Thought Experiments ◽  
Newtonian Gravity ◽  
Algebraic Equations ◽  
Schwarzschild Geometry

Abstract We show that mass parameter and radial marker values can be indirectly measured in thought experiments performed in Schwarzschild spacetime, without using the Newtonian limit of general relativity or approximations based on Euclidean geometry. Our approach involves different proper time quantifications as well as solutions to systems of algebraic equations, and aims to strengthen the conceptual independence of general relativity from Newtonian gravity.

Asymptotic numerical solver for the linear Klein–Gordon equation with space- and time-dependent mass

2021 ◽  
Vol 115 ◽  
pp. 106935
Author(s):  
Marissa Condon ◽  
Karolina Kropielnicka ◽  
Karolina Lademann ◽  
Rafał Perczyński
Keyword(s):  
Gordon Equation ◽  
Time Dependent ◽  
Space And Time ◽  
Klein Gordon ◽  
Numerical Solver ◽  
Dependent Mass ◽  
Klein Gordon Equation

scholarly journals Status and Needs of Astrometry

1979 ◽  
Vol 50 ◽  
pp. 19-1-19-9
Author(s):  
James A. Hughes
Keyword(s):  
Stellar Evolution ◽  
Proper Motion ◽  
Reference System ◽  
Binary Star ◽  
Stellar Dynamics ◽  
Inertial Reference Frame ◽  
Star Studies ◽  
The Status ◽  
Near Future ◽  
Fundamental Reference

AbstractA review will be presented of the status of the fundamental reference system. Mention will be made of the problems limiting the accuracy of transit circles and photographic astrometry and attempts at possible improvments in the near future. The progress in the preparation of the FK5 will be briefly mentioned, as will be the various methods used to approximate an inertial reference frame. Needs for higher accuracy in Astronomy fall in the area of better modeling of the Earth's motion (rotation, nutation, precession, the ecliptic, etc.) as well as a parallax and proper motion determination for galactic structure studies, stellar dynamics and stellar evolution. It will be assumed that interferometric binary star studies will be discussed elsewhere.

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