Influence of scalar field in massive particle motion in JNW spacetime

TL;DR

This study explores how scalar fields influence massive particle motion and oscillations in JNW spacetime, analyzing effects on stable orbits, radiation, and QPOs, with implications for understanding naked singularities in strong gravity regimes.

Contribution

It introduces a detailed analysis of scalar coupling effects on particle dynamics, oscillation frequencies, and QPOs in JNW spacetime, including MCMC parameter constraints from X-ray binary data.

Findings

ISCO radius depends on scalar coupling parameter

Radiation reaction minimally affects particle trajectories

Scalar field alters oscillation frequencies and QPO ratios

Abstract

In this paper, we investigated the motion of massive particles in the presence of scalar and gravitational fields, particularly focusing on the Janis-Newman-Winicour (JNW) naked singularity solution. It is shown that the innermost stable circular orbit (ISCO) radius strongly depends on scalar coupling parameter. Additionally, we explored the radiation reaction effects on particle dynamics, incorporating a reaction term into the motion equations. Numerical simulations indicated minimal impact on particle trajectories from radiation reaction. We also examined the oscillatory motion of particles around compact objects in the JNW spacetime, focusing on radial and vertical oscillations. Our analysis indicated that the scalar field's coupling parameter and the spacetime deformation parameter $n$ significantly alter the fundamental frequencies of these oscillations. Furthermore, we studied quasi-periodic oscillations (QPOs) in X-ray binaries, using the relativistic precession (RP) model to analyze upper and lower frequency relationships. Our results indicated that increasing parameters ($n$ and $g_s$) shifts the frequency ratio of 3:2 QPOs closer to the naked singularity, with $n$ decreasing and $g_s$ increasing both frequencies. Finally, we analyzed QPO data from selected four X-ray binary systems using Markov Chain Monte Carlo (MCMC) analysis to constrain JNW parameters. Our findings provided insights into the mass, coupling and deformation parameter for each system, enhancing our understanding of compact object dynamics in strong gravitational fields.