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Cometary showers and unseen solar companions
External Online Source: doi:10.1038/312380a0
Author and Affiliation:
Weissman, P. R.(California Institute of Technology, Jet Propulsion Laboratory, Earth and Space Sciences Div., Pasadena, CA, United States)
Abstract: The possibility that an invisible solar companion passing through the Oort cloud every 28 Myr precipitates a sufficiently high rate of cometary collisions with the earth to account for periodic mass species extinctions recorded in the fossil record is discussed. A Monte Carlo simulation shows that any hypothesized 'death star' with a 28 Myr orbit would experience an average 10 percent change in period per orbit. Production of an 18-fold increase in cometary impacts would be associated with a 0.055 probability that a 10 km nucleus would hit the earth in a shower once every 510 Myr, longer than the proposed extinction periodicity. However, if the death star orbit has a 0.6 eccentricity and the Oort cloud is sufficiently densely populated, a 2 billion comet shower may be possible. A survey of large terrestrial impact craters indicates that 6-12 craters with diameters over 10 km originated in periodic showers. The extinctions in any case occur at 26 Myr periods and cannot be correlated with the 33 Myr period of recrossing the galactic plane, or with any other known phenomena.
Publication Date: Nov 22, 1984
Document ID:
19850035178
(Acquired Nov 28, 1995)
Accession Number: 85A17329
Subject Category: ASTRONOMY
Document Type: Journal Article
Publication Information: Nature; p. 380; Rep; (ISSN 0028-0836); 312
Publisher Information: United Kingdom
Financial Sponsor: NASA; United States
Organization Source: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA, United States
Description: 2p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ASTRONOMICAL MODELS; BINARY STARS; COMETS; COMPANION STARS; NEMESIS (STAR); SOLAR SYSTEM; COMETARY COLLISIONS; CRATERING; EARTH SURFACE; EXTINCTION; OORT CLOUD; PRECIPITATES; SUN
Imprint And Other Notes: Nature (ISSN 0028-0836), vol. 312, Nov. 22, 1984, p. 380; Reply, p. 380, 381.
Miscellaneous Notes: 380, 381
Availability Source: Other Sources
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