{
  "abstract": "We investigate the degeneracies between black hole (BH) spin effects and parametrized post-Newtonian (PPN) parameters in the relativistic orbital dynamics of S2-like and S62-like stars orbiting Sagittarius A$^{\\ast}$. Using a 1PN+SO Hamiltonian framework and synthetic astrometric and radial velocity datasets, we perform Bayesian parameter inference. For current baseline observational precisions, the dominant relativistic observable--the Schwarzschild periapsis advance--allows the recovery of the effective precession parameter $Υ$, while leaving the individual PPN parameters $γ$ and $β$ degenerate. Assuming microarcsecond-level astrometric precision, the spin-induced Lense-Thirring signal becomes partially detectable; fixing the PPN sector to General Relativity allows the BH spin magnitude to be constrained to an uncertainty of $\\sim10^{-2}$. However, simultaneously varying PPN and spin parameters reveals a strong, approximately linear covariance between $Υ$ and the dimensionless spin parameter $χ$. To overcome this limitation, we demonstrate that joint multi-star inference can disentangle the degeneracy by combining a wider-orbit star, which constrains the dominant 1PN sector, with a compact relativistic orbit that is sensitive to Lense-Thirring frame dragging.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: MNRAS 551, stag1407 (2026)",
  "arxiv": "2609.05172",
  "author_total": 1,
  "authors": [
    {
      "name": "Shant Khlghatyan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/b3qhjq9njqkgw.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.05172",
  "fulltext_url": null,
  "id": "b3qhjq9njqkgw",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.05172",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.05172",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/b3qhjq9njqkgw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:14Z",
      "native_id": "2609.05172",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.05172"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "PPN--spin degeneracies in mock S62-like stellar-orbit inference",
  "title_text": "PPN--spin degeneracies in mock S62-like stellar-orbit inference",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:14Z",
  "url": "https://research.draconitic.com/paper/b3qhjq9njqkgw",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1093/mnras/stag1407",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}