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Nongravitational Motion of 3I/ATLAS Far from the Sun: Robust Detection, Weak Constraints on the Activity Law — arXiv:2610.38485

Source: arXiv (en)
Original: https://arxiv.org/abs/2610.38485
License (as archived): CC0-1.0
Archived: 2026-11-01T02:56:52.408Z
SHA-256 of the archived text: ddc56cda015b3e0f4cd03174b119689416d2063082a1f60d5f1e8c0d1788fc01
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How to cite

Nongravitational Motion of 3I/ATLAS Far from the Sun: Robust Detection, Weak Constraints on the Activity Law — arXiv:2610.38485 — arXiv (en), https://arxiv.org/abs/2610.38485 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_cbc43ecddeee (Metraipolis archive dc_cbc43ecddeee, sha256 ddc56cda015b3e0f4cd03174b119689416d2063082a1f60d5f1e8c0d1788fc01)

BibTeX

@misc{dccbc43ecddeee,
  title = {Nongravitational Motion of 3I/ATLAS Far from the Sun: Robust Detection, Weak Constraints on the Activity Law — arXiv:2610.38485},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2610.38485},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_cbc43ecddeee; sha256 ddc56cda015b3e0f4cd03174b119689416d2063082a1f60d5f1e8c0d1788fc01},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2610.38485. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

3I/ATLAS provides an unprecedented astrometric data set for studying nongravitational (NG) effects in an interstellar object, but existing orbital solutions depend strongly on assumptions regarding the heliocentric activity law and the treatment of the astrometric data. We investigate the extent to which astrometric observations constrain the heliocentric dependence of the NG activity function, focusing on the identifiability of different functional forms of $g(r)$ within standard NG orbit-determination frameworks. Astrometric observations obtained at heliocentric distances larger than 3.49 au before perihelion and 2.67 au after perihelion were analysed. Purely gravitational and nongravitational orbital solutions were determined using several activity laws, including the standard water-ice sublimation law and flatter more volatile ice prescriptions. The resulting residual distributions were evaluated using normality tests and analyses of temporal trends in the observed-minus-calculated residuals. The distant pre-perihelion observations are well described by a purely gravitational (GR) orbit, whereas the distant post-perihelion data exhibit a statistically significant non-Gaussian residual distribution under the GR model. When the distant pre- and post-perihelion observations are combined, nongravitational acceleration becomes clearly detectable through a significant reduction in the residual rms and the disappearance of systematic residual trends. However, the astrometric data do not uniquely distinguish between the tested activity laws: standard water-ice, more volatile and extreme volatile prescriptions produce statistically comparable orbital fits despite their markedly different heliocentric dependences. The existence of nongravitational acceleration is therefore considerably better constrained by astrometry than its physical origin or heliocentric dependence.

Tema degli esploratori: fisica e astronomia (elenco arXiv astro-ph.EP, nuovi lavori del giorno).
Categorie arXiv: Earth and Planetary Astrophysics (astro-ph.EP) ; Astrophysics of Galaxies (astro-ph.GA).
Pagina del lavoro: https://arxiv.org/abs/2610.38485 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-11-01T02:22:43.237Z dalla pagina https://arxiv.org/list/astro-ph.EP/new (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).