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arxiv: 2605.01639 · v1 · submitted 2026-05-02 · 🌀 gr-qc

Shirokov and Shapiro Effects in the Hartle-Thorne Spacetime

Anuar Idrissov , Kuantay Boshkayev , Serzhan Momynov , Hernando Quevedo , Daniya Utepova , Ainur Urazalina , Bagila Baitimbetova This is my paper

Pith reviewed 2026-05-09 13:49 UTC · model grok-4.3

classification 🌀 gr-qc
keywords effectsspacetimeangularcompacthartle-thornemomentumobjectsquadrupole
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The pith

In the Hartle-Thorne metric, angular momentum J and quadrupole moment Q couple radial and azimuthal oscillations in the Shirokov effect and alter Shapiro time delay, with oblate shapes increasing delay and frame-dragging persisting for both signs of J.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The Hartle-Thorne spacetime models gravity around slowly spinning and slightly flattened stars. The authors use geodesic deviation equations to track how nearby particle paths oscillate, finding that spin and shape deformation link radial and sideways motions together in the Shirokov effect. They compare this to earlier calculations in other metrics and see similar coupling trends. For the Shapiro effect, where light takes extra time passing near mass, they examine pure spin cases and pure deformation cases separately. More oblate shapes produce stronger delays at larger distances, while spin affects the delay regardless of direction. They also run full numerical calculations without weak-field approximations to check how spin and deformation can produce similar observable signatures.

Core claim

Using geodesic deviation equations, we analyze the oscillatory motion of neighboring test particle trajectories and show how the combined impact of angular momentum J and quadrupole moment Q affects the Shirokov effect.

Load-bearing premise

The Hartle-Thorne spacetime accurately describes the exterior gravitational field of slowly rotating, slightly deformed celestial objects, allowing the geodesic deviation analysis to capture the relevant physics.

read the original abstract

We investigate the influence of rotation and quadrupole deformations of astrophysical compact objects on the Shirokov and Shapiro effects within the Hartle-Thorne spacetime, which describes the exterior gravitational field of slowly rotating, slightly deformed celestial objects. Using geodesic deviation equations, we analyze the oscillatory motion of neighboring test particle trajectories and show how the combined impact of angular momentum $J$ and quadrupole moment $Q$ affects the Shirokov effect. The results are compared with our previous analysis for the Lense-Thirring and Zipoy-Voorhees metrics, revealing consistent trends in the coupling between radial and azimuthal oscillations. For the Shapiro time delay, we examine two limiting configurations: (i) the Lense-Thirring frame-dragging case with $J^2=0$, $Q=0$ and $J\neq0$, where the effect persists for both positive and negative values of the angular momentum; and (ii) the static quadrupolar case with $J=0$ and $Q\neq0$, where more oblate sources produce a stronger gravitational time delay with increasing distance. We also study these effects in the Hartle-Thorne spacetime without employing the weak-field approximation, performing a full numerical analysis. In particular, we examine the mimicking effects produced by the quadrupole deformation and the angular momentum of the compact object. These results illustrate how the deformation and rotation of compact objects influence the relativistic observables in the surrounding spacetime.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Based on the abstract alone, the central claims rest on the standard geodesic deviation formalism of general relativity and the definition of the Hartle-Thorne metric as an approximation for slowly rotating, slightly deformed objects; no new free parameters, invented entities, or ad-hoc axioms are introduced beyond those in the cited prior metrics.

axioms (1)
  • domain assumption The Hartle-Thorne metric accurately describes the exterior gravitational field of slowly rotating, slightly deformed celestial objects.
    Invoked at the outset to justify applying geodesic deviation equations to this spacetime.

pith-pipeline@v0.9.0 · 5590 in / 1328 out tokens · 54149 ms · 2026-05-09T13:49:36.036299+00:00 · methodology

discussion (0)

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