% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Pfalzner:893878,
      author       = {Pfalzner, Susanne and Aizpuru Vargas, Luis L. and Bhandare,
                      Asmita and Veras, Dimitri},
      title        = {{S}ignificant interstellar object production by close
                      stellar flybys},
      journal      = {Astronomy and astrophysics},
      volume       = {651},
      issn         = {0004-6361},
      address      = {Les Ulis},
      publisher    = {EDP Sciences},
      reportid     = {FZJ-2021-02890},
      pages        = {A38 -},
      year         = {2021},
      abstract     = {Context. Within just two years, two interstellar objects
                      (ISOs) – 1I/‘Oumuamua and 2I/Borisov – have been
                      discovered, the first of their kind. Large quantities of
                      planetesimals form as a by-product of planet formation.
                      Therefore, it seems likely that ISOs are former
                      planetesimals that became somehow unbound from their parent
                      star. The discoveries raise the question of the dominant ISO
                      formation process.Aims. Here, we concentrate on
                      planetesimals released during another star’s close flybys.
                      Such close flybys happen most frequently during the first 10
                      Myr of a star’s life. Here, we quantify the amount of
                      planetesimals released during close stellar flybys, their
                      ejection velocity and likely composition.Methods. We
                      numerically study the dependence of the effect of parabolic
                      flybys on the mass ratio between the perturber and parent
                      star, the periastron distance, inclination, and angle of
                      periastron.Results. As expected, close prograde flybys of
                      high-mass stars produce the most considerable amount of
                      ISOs. Especially flybys of stars with M > 5 M⊙ on
                      trajectories closer than 250 AU can lead to more
                      planetesimals turning into ISOs than remaining bound to the
                      parent star. Even strongly inclined orbits do not
                      significantly reduce the ISO production; only retrograde
                      flybys lead to a significantly lower ISO production. For
                      perturbers slightly more massive than the parent star, there
                      is a competition between ISO production and planetesimals
                      being captured by the perturber. Whenever ISOs are produced,
                      they leave their parent system typically with velocities in
                      the range of 0.5–2 km s−1. This ejection velocity is
                      distinctly different to that of ISOs produced by planet
                      scattering (~4–8 km s−1) and those shed during the
                      stellar post-main-sequence phase (~0.1–0.2 km s−1).
                      Using the typical disc truncation radius in various cluster
                      environments, we find that clusters like the Orion nebula
                      cluster are likely to produce the equivalent of 0.85
                      Earth-masses of ISOs per star. In contrast, compact clusters
                      like NGC 3603 could produce up to 50 Earth-masses of ISOs
                      per star. Our solar-system probably produced the equivalent
                      of 2–3 Earth masses of ISOs, which left our solar system
                      at a mean ejection velocity of 0.7 km s−1.Conclusions.
                      Most ISOs produced by flybys should be comet-like, similar
                      to Borisov and unlike ‘Oumuamua. ISOs originating from
                      compact long-lived clusters would often show a deficiency in
                      CO. As soon as a statistically significant sample of ISOs is
                      discovered, the combined information of their observed
                      velocities and composition might help in constraining the
                      dominant production process.},
      cin          = {JSC},
      ddc          = {520},
      cid          = {I:(DE-Juel1)JSC-20090406},
      pnm          = {5111 - Domain-Specific Simulation $\&$ Data Life Cycle Labs
                      (SDLs) and Research Groups (POF4-511)},
      pid          = {G:(DE-HGF)POF4-5111},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000672718400004},
      doi          = {10.1051/0004-6361/202140587},
      url          = {https://juser.fz-juelich.de/record/893878},
}