The orbit and nature of the semi-detached stellar companion of Sgr A* super-massive blackhole

TL;DR

This paper proposes a model where a star orbits Sgr A* with specific periods, explaining observed periodicities in X-ray and NIR flares and aligning with recent hotspot motion observations.

Contribution

It introduces a detailed orbit and rotation model of a star around Sgr A*, linking multiple observed periodicities to this star's motion and internal structure.

Findings

Identification of three consistent periodicities in flare timings.

A specific orbital radius of approximately 3.13 Schwarzschild radii.

Alignment with recent hotspot motion observations by GRAVITY.

Abstract

In three previous papers I showed that the series of the midpoints of the times of all the X-ray flares of Sgr A* that have been detected so far harbor a statistical trend termed pacemaker regularity. This means that X-ray flares are detected more frequently around time points that are a subset of a periodic grid on the time axis of period P_X=0.1032 day=149 minutes. The series of the times of detection of the peaks of near IR (NIR) flares of the object are also regulated by a pacemaker with a period of P_IR=0.028 day=41 minutes. Here, I show that the series of the midpoints of the times of recorded NIR flares are also regulated by a pacemaker of the period P_IRM=0.039 day=56 minutes. The two pacemakers found in the previous papers were interpreted as signals of a star that revolves around the black hole of Sgr A* in orbit with a mean radius of ~3.2 Schwarzschild radii of the black hole, here corrected to ~3.13. The finding of the period of the third pacemaker is consistent with the suggested revolving star model. Here, I present the specific orbit of the star as well as a plausible description of its sidereal rotation. The model also implies that the star has an unusual internal structure. I show that the discovery of the GRAVITY collaboration of the motion of hotspots at distances from the black hole that are of the order of very few Schwarzschild radii of it may well be understood within the context of the revolving star model.