Are periodic mass extinctions driven by a distant solar companion?

@article{Whitmire1984ArePM,
  title={Are periodic mass extinctions driven by a distant solar companion?},
  author={Daniel P. Whitmire and Albert A. Jackson},
  journal={Nature},
  year={1984},
  volume={308},
  pages={713-715}
}
Raup and Sepkoski1–3 have recently reported evidence for a 26-Myr cycle in biological mass extinctions which, if real, requires an astronomical explanation. Here we investigate a model in which this extinction cycle is associated with the orbital period of a solar companion star. The required semi-major axis is (a*), semi-major axis) ≈ 8.8 × 104 AU = 1.4 light yr. Its highly eccentric orbit (e* \[gsims] 0.9) periodically brings the companion into the dense inner region (\[lsims]2 × 104 AU) of… 

Orbital stability of the unseen solar companion linked to periodic extinction events

Recent suggestions of astronomical causes for the closely periodic extinction events in the geological record1 and the possible periodicities in the cratering record2 have involved two basic ideas.

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How stable is an astronomical clock that can trigger mass extinctions on Earth?

  • P. Hut
  • Physics, Geology
    Nature
  • 1984
The periodicity in mass extinctions observed in the fossil record1,2 may be driven by an astronomical clock consisting of a companion star to the Sun3,4. Each perihelion passage of the companion star

Periodic comet showers and planet X

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It has been suggested1,2 that the observed periodic extinction of species at intervals of 26 Myr (ref. 3) may be catalysed by a hypothetical stellar companion of the Sun, Nemesis, with an orbital

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Passing stars can perturb the Oort Cloud, triggering comet showers and potentially extinction events on Earth. We combine velocity measurements for the recently discovered, nearby, low-mass binary

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The observed frequency of passages of Earth-crossing long-period (LP) comets (P > 200 yr) is about three per year for comets brighter than absolute magnitude H10 ~ 10.5. About one out of six LP
...

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