arXiv subjects

Leonardus B. Putra

Publications and source records attributed to Leonardus B. Putra.

5 recordsLinked to original sources

arXiv2026

Stability of equilibrium points in modified elliptic restricted three-body problem with various perturbation sources

This study examines the dynamics of the third body in an elliptic restricted three-body problem (ERTBP) framework, taking into account perturbations from radiation pressure, oblateness, and elongation of the primary bodies, as well as disk-like structures. The objectives are to determine the positions and stability of the equilibrium points, asses how these points shift under the influence of perturbations, and evaluate the dependence of their stability on the orbital eccentricity and perturbation parameters. The ERTBP model is modified to include a radiating, oblate primary body and an elongated secondary body modeled as a finite straight segment, alongside perturbations from a surrounding disk. The system's equations of motion are numerically solved using parameters from perturbed and classical cases. Equilibrium positions are computed over a range of eccentricities and perturbation values, and stability is analyzed using linearized equations and eigenvalue methods. In all cases, we have found three collinear ($L_1$, $L_2$, $L_3$) and two non-collinear ($L_4$, $L_5$) equilibrium points solutions. The inclusion of radiations, oblateness, elongation using a finite straight segment, and disk perturbation systematically displaces each equilibrium point from its classical location, with the magnitude and direction of the displacement varying with the perturbation parameter. Stability analysis confirms that the collinear points remain linearly stable under all tested conditions. Meanwhile, non-collinear points are stable under a specific condition. We investigate the stability boundary of these points as a function of orbital eccentricity and we found there is a critical range of eccentricity values within which stability is preserved.

astro-ph.EP↗

arXiv2025

Orbital dynamics and spin-precession around a circular chiral vorton

Vortons are of interest in high-energy physics as possible dark matter candidates and as probes of Grand Unified Theories. Using the recently derived weak-field metric for a chiral vorton, we study the dynamics of test particles by analyzing both timelike and null geodesics. We identify several classes of trajectories, including bound precessing orbits, circular orbits, toroidal, and crown-type oscillations, as well as unbound scattering paths. Poincare surfaces of section reveal transitions between regular and chaotic motions that depend sensitively on the vorton tension $Gμ$ and initial conditions. We further compute the Lense-Thirring and general spin-precession frequencies for gyroscopes along Killing trajectories. The resulting precession profiles exhibit several distinct features not present in Kerr black holes but reminiscent of Kerr naked singularities, such as: divergences near the ring core, and multi-minima structures. These dynamical and precessional signatures may offer potential observational pathways for detecting vortons.

gr-qc↗

arXiv2025

Gravitational lensing by non-self-intersecting vortons

We investigate the gravitational lensing signatures of vorton configurations, considering the circular vorton, the Kibble-Turok vorton, and a newly proposed class that incorporates simultaneous excitations of the first, second, and third harmonic modes. Working within the weak-field and thin-lens approximations, we demonstrate that circular vortons produce a sharp lensing discontinuity that separates two regions with qualitatively distinct distortions. The corresponding Einstein ring co-exists alongside an almost undistorted source image. This effect is significantly amplified in the case of non-circular vortons, where asymmetries and higher-harmonic deformations amplify the discontinuity and lead to complex image structures. These distinctive lensing patterns offer potential discriminants between different vorton configurations, suggesting that future high-resolution surveys may provide a novel window into the microphysics of current-carrying cosmic strings.

hep-th↗

arXiv2025

Gravitational field and lensing of a circular chiral vorton

We derive the metric of a circular chiral vorton in the weak field limit. The object is self-supporting by means of its chiral current. A conical singularity with deficit angle, identical to that of straight string with the same linear mass density, is present at the vorton's core. We find that the metric is akin to the electromagnetic $4$-potential of a circular current wire loop, illustrating the concept of gravito-electromagnetism. Surprisingly we find that the solution asymptotically mimics a Kerr-like naked singularity with mass $M_v=4πRμ$ and spin parameter $a=R/2$. Finally, we also simulate the gravitational lensing images by solving the corresponding null geodesic equations. This reveals interesting properties of the images, such as the simultaneous creation of a minimally distorted source image and its Einstein ring, as well as the formation of double images on the back side of the ring.

gr-qc↗

arXiv2024

Effects of Variable Mass, Disk-Like Structure, and Radiation Pressure on the Dynamics of Circular Restricted Three-Body Problem

In this paper, we intend to investigate the dynamics of the Circular Restricted Three-Body Problem. Here we assumed the primaries as the source of radiation and have variable mass. The gravitational perturbation from disk-like structure are also considered in this study. There exist five equilibrium points in this system. By considering the combined effect from disk-like structure and the mass transfer, we found that the classical collinear equilibrium points depart from x-axis. Meanwhile, this combined effect also breaks the symmetry of tringular equlibrium point positions. We noted that the quasi-equilibrium points are unstable whereas the triangular equilibrium points are stable if the mass ratio $μ$ smaller than critical mass $μ_c$. It shows that the stability of triangular equilibrium points depends on time.

astro-ph.EP↗