---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21760'
abstract:
- lang: eng
  text: 3I/ATLAS is the third interstellar object discovered to date, following 1I/‘Oumuamua
    and 2I/Borisov. Its unusually high excess velocity and active cometary nature
    make it a key probe of the Galactic population of icy planetesimals. Understanding
    its origin requires its past trajectory through the Galaxy to be traced and the
    possible role of stellar encounters to be assessed, both as a potential origin
    and a perturber to its orbit. We integrated the orbit of 3I/ATLAS backward in
    time for 10 Myr, together with a sample of Gaia DR3 stars with high-quality astrometry
    and radial velocities, to identify close passages within 2 pc. We identify 93
    nominal encounters, 62 of which are significant at the 2σ level. However, none
    of these encounters produced any meaningful perturbation. The strongest perturber
    Gaia DR3 6863591389529611264 at 0.30 pc and with a relative velocity of 35 km
    s−1, imparted only a velocity change of ∣Δv∣  ≃  5  ×  10−4 km s−1 to the orbit
    of 3I/ATLAS. Our results indicate that no stellar flybys within the past 10 Myr
    and 500 pc contained in Gaia DR3 can account for the present trajectory of 3I/ATLAS
    or be associated with its origin. We further show that 3I/ATLAS is kinematically
    consistent with a thin-disk population, despite its large peculiar velocity.
acknowledgement: We thank the anonymous referee for a careful reading of the manuscript
  and for constructive comments that improved the paper. X.P.C. and S.T. thank J.L.
  Gragera-Más and Ylva Götberg for their valuable feedback and comments. X.P.C. acknowledges
  financial support from the Spanish National Programme for the Promotion of Talent
  and its Employability grant PRE2022-104959 cofunded by the European Social Fund.
  S.T. acknowledges the funding from the European Union’s Horizon 2020 research and
  innovation program under the Marie Skłodowska-Curie grant agreement No. 101034413.
  E.V. acknowledges support from the DISCOBOLO project funded by the Spanish Ministerio
  de Ciencia, Innovación y Universidades under grant PID2021-127289NB-I00. A.J.M.
  acknowledges support from the Swedish National Space Agency (Career grant 2023-00146).
  X.P.C. and M.M. acknowledge support from the Spanish Ministerio de Ciencia, Innovaciòn
  y Universidades under grants PID2021122842OB-C22 and PID2024-157964OB-C22; from
  the Xunta de Galicia and the European Union (FEDER Galicia 2021-2027 Program) Ref.
  ED431B 2024/21, ED431B 2024/02, and CITIC ED431G 2023/01. This work has made use
  of data from the European Space Agency (ESA) Gaia mission and processed by the Gaia
  Data Processing and Analysis Consortium (DPAC). Funding for the DPAC has been provided
  by national institutions, particularly the institutions participating in the Gaia
  Multilateral Agreement.
article_number: '146'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: X.
  full_name: Pérez-Couto, X.
  last_name: Pérez-Couto
- first_name: Santiago
  full_name: Torres Rodriguez, Santiago
  id: a8df4360-4328-11ee-8f1a-e502d0c83fc2
  last_name: Torres Rodriguez
  orcid: 0000-0002-3150-8988
- first_name: E.
  full_name: Villaver, E.
  last_name: Villaver
- first_name: A. J.
  full_name: Mustill, A. J.
  last_name: Mustill
- first_name: M.
  full_name: Manteiga, M.
  last_name: Manteiga
citation:
  ama: 'Pérez-Couto X, Torres Rodriguez S, Villaver E, Mustill AJ, Manteiga M. 3I/ATLAS:
    In search of the witnesses to its voyage. <i>The Astrophysical Journal</i>. 2026;1001(2).
    doi:<a href="https://doi.org/10.3847/1538-4357/ae56ff">10.3847/1538-4357/ae56ff</a>'
  apa: 'Pérez-Couto, X., Torres Rodriguez, S., Villaver, E., Mustill, A. J., &#38;
    Manteiga, M. (2026). 3I/ATLAS: In search of the witnesses to its voyage. <i>The
    Astrophysical Journal</i>. IOP Publishing. <a href="https://doi.org/10.3847/1538-4357/ae56ff">https://doi.org/10.3847/1538-4357/ae56ff</a>'
  chicago: 'Pérez-Couto, X., Santiago Torres Rodriguez, E. Villaver, A. J. Mustill,
    and M. Manteiga. “3I/ATLAS: In Search of the Witnesses to Its Voyage.” <i>The
    Astrophysical Journal</i>. IOP Publishing, 2026. <a href="https://doi.org/10.3847/1538-4357/ae56ff">https://doi.org/10.3847/1538-4357/ae56ff</a>.'
  ieee: 'X. Pérez-Couto, S. Torres Rodriguez, E. Villaver, A. J. Mustill, and M. Manteiga,
    “3I/ATLAS: In search of the witnesses to its voyage,” <i>The Astrophysical Journal</i>,
    vol. 1001, no. 2. IOP Publishing, 2026.'
  ista: 'Pérez-Couto X, Torres Rodriguez S, Villaver E, Mustill AJ, Manteiga M. 2026.
    3I/ATLAS: In search of the witnesses to its voyage. The Astrophysical Journal.
    1001(2), 146.'
  mla: 'Pérez-Couto, X., et al. “3I/ATLAS: In Search of the Witnesses to Its Voyage.”
    <i>The Astrophysical Journal</i>, vol. 1001, no. 2, 146, IOP Publishing, 2026,
    doi:<a href="https://doi.org/10.3847/1538-4357/ae56ff">10.3847/1538-4357/ae56ff</a>.'
  short: X. Pérez-Couto, S. Torres Rodriguez, E. Villaver, A.J. Mustill, M. Manteiga,
    The Astrophysical Journal 1001 (2026).
date_created: 2026-04-26T22:01:46Z
date_published: 2026-04-20T00:00:00Z
date_updated: 2026-04-28T13:08:39Z
day: '20'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.3847/1538-4357/ae56ff
ec_funded: 1
external_id:
  arxiv:
  - '2509.07678'
file:
- access_level: open_access
  checksum: c3daf49261a9933c079854c38eec316f
  content_type: application/pdf
  creator: dernst
  date_created: 2026-04-28T13:06:00Z
  date_updated: 2026-04-28T13:06:00Z
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  file_size: 2905627
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  success: 1
file_date_updated: 2026-04-28T13:06:00Z
has_accepted_license: '1'
intvolume: '      1001'
issue: '2'
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
  call_identifier: H2020
  grant_number: '101034413'
  name: 'IST-BRIDGE: International postdoctoral program'
publication: The Astrophysical Journal
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: '3I/ATLAS: In search of the witnesses to its voyage'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 1001
year: '2026'
...