Dynamical constraints on the mass and perihelion distance of Nemesis and the stability of its orbit

It has been suggested 1,2 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 period of 26 Myr. The passage of a stellar companion through the inner comet cloud 4 will fill the loss...

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Bibliographic Details
Published in:Nature (London) 1984-10, Vol.311 (5987), p.636-638
Main Author: Hills, J. G
Format: Article
Language:English
Subjects:
Astronomy
Earth, ocean, space
Exact sciences and technology
Humanities and Social Sciences
letter
multidisciplinary
Other topics on the solar system
Science
Science (multidisciplinary)
Solar system
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Summary:It has been suggested 1,2 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 period of 26 Myr. The passage of a stellar companion through the inner comet cloud 4 will fill the loss cone of these comets and cause a comet shower to enter the planetary system. It has been estimated that about 20–30 comets will hit the Earth during a shower, which lasts less than a million yr. Such Earth impacts would produce considerable environmental stress and may lead to widespread extinction of species 4 . I now investigate the effect of Nemesis on the comets in the inner comet cloud. This is used to determine the minimum required mass of Nemesis and its minimum required perihelion distance. The effect of passing stars on the stability of the orbit of Nemesis is investigated, and the probability of its having passed within the planetary system estimated.
ISSN:0028-0836
1476-4687
DOI:10.1038/311636a0