Rotation Period of 3I/ATLAS After Perihelion from Jet Position Angle Wobble and Photometric Variability
Fuente:
arXiv
Saved in:
| Main Authors: | , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915734168272896 |
|---|---|
| author | Scarmato, Toni Loeb, Abraham |
| author_facet | Scarmato, Toni Loeb, Abraham |
| contents | We determine the post-perihelion rotation period of 3I/ATLAS using two independent diagnostics: the temporal modulation of the position angle (PA) of a persistent jet-like feature, and a time-series photometric light curve in the Gr (R) band. For the jet morphology, we measure the PA at multiple epochs by applying the Larson-Sekanina Rotational Gradient filter to Hubble Space Telescope images between November 20, 2025 and December 27, 2025, and model the phase-folded PA curve with weighted least-squares Fourier series up to two harmonics while scanning trial periods P to identify minima in \c{hi}2(P). For the photometry, we adopt the best-fit period from an independent 30-minute binned analysis (from a 0.25 meter telescope MPC L92) based on a refined \c{hi}2(P) profile for a sinusoidal model with nightly offsets. We find that the jet-PA modulation gives a period Pjet = 7.20 +/-0.05 h (adopting a conservative uncertainty dominated by sparse sampling and systematics), while the photometry yields Pphot = 7.136+/-0.001 h (formal 1σ uncertainty). Although the periods differ slightly, the offset is plausibly attributable to non-Gaussian systematics and aliasing. The combined data supports a post-perihelion rotation period of 7.1 h associated with precession of the jet structure around the rotation axis by 20°. The rotation axis is aligned with the sunward direction to within 20° |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_10860 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Rotation Period of 3I/ATLAS After Perihelion from Jet Position Angle Wobble and Photometric Variability Scarmato, Toni Loeb, Abraham Earth and Planetary Astrophysics Astrophysics of Galaxies Solar and Stellar Astrophysics F.2.2 We determine the post-perihelion rotation period of 3I/ATLAS using two independent diagnostics: the temporal modulation of the position angle (PA) of a persistent jet-like feature, and a time-series photometric light curve in the Gr (R) band. For the jet morphology, we measure the PA at multiple epochs by applying the Larson-Sekanina Rotational Gradient filter to Hubble Space Telescope images between November 20, 2025 and December 27, 2025, and model the phase-folded PA curve with weighted least-squares Fourier series up to two harmonics while scanning trial periods P to identify minima in \c{hi}2(P). For the photometry, we adopt the best-fit period from an independent 30-minute binned analysis (from a 0.25 meter telescope MPC L92) based on a refined \c{hi}2(P) profile for a sinusoidal model with nightly offsets. We find that the jet-PA modulation gives a period Pjet = 7.20 +/-0.05 h (adopting a conservative uncertainty dominated by sparse sampling and systematics), while the photometry yields Pphot = 7.136+/-0.001 h (formal 1σ uncertainty). Although the periods differ slightly, the offset is plausibly attributable to non-Gaussian systematics and aliasing. The combined data supports a post-perihelion rotation period of 7.1 h associated with precession of the jet structure around the rotation axis by 20°. The rotation axis is aligned with the sunward direction to within 20° |
| title | Rotation Period of 3I/ATLAS After Perihelion from Jet Position Angle Wobble and Photometric Variability |
| topic | Earth and Planetary Astrophysics Astrophysics of Galaxies Solar and Stellar Astrophysics F.2.2 |
| url | https://arxiv.org/abs/2601.10860 |