The Elemental Composition of the Corona of Procyon: Evidence for the Absence of the FIP Effect     

Drake JJ  Laming JM  Widing KG  Schmitt JH  Haisch B  Bowyer S 《Science (New York, N.Y.)》1995,267(5203):1470-1473

The chemical composition of the solar corona is not the same as that of the underlying photosphere. In the corona, elements with a first ionization potential (FIP) of /=10 electron volts (for example, oxygen, neon, and sulfur) by factors of 3 to 10 with respect to the photosphere. The origin of this FIP effect is unknown. The launch of the Extreme Ultraviolet Explorer Satellite (EUVE) opened up the spectroscopic capability required to determine elemental abundances in the coronae of other stars. Spectroscopic observations of the corona of the nearby F5 IV star Procyon obtained with EUVE have yielded estimates of the relative abundances of high- and low-FIP species. The results provide evidence that Procyon, unlike the sun, does not exhibit the FIP effect. Whether the sun or Procyon is more typical of the general late-type stellar population is of fundamental interest to the physics of stellar outer atmospheres and has a bearing on the origin of cosmic rays.  相似文献   

Mineralogy and composition of lunar fines and selected rocks     

Frondel C  Klein C  Ito J  Drake JC 《Science (New York, N.Y.)》1970,167(3918):681-683

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South american geochronology: radiometric time scale for middle to late tertiary mammal-bearing horizons in patagonia     

Marshall LG  Pascual R  Curtis GH  Drake RE 《Science (New York, N.Y.)》1977,195(4284):1325-1328

Radiometric (potassium-argon) age determinations for basalts and tuffs associated with middle to late Tertiary mammal-bearing horizons in Patagonia, southern Argentina, permit refinement of boundaries and hiatuses between beds of Deseadan (early Oligocene) through Friasian (middle to late Miocene) age. At two localities beds of Deseadan age are overlain by basalts, which gave dates of 33.6 and 35.4 million years ago; 34.0 million years ago is tentatively accepted as a terminal date for known Deseadan. At several localities beds of Colhuehuapian age are underlain by basalts, which gave dates ranging from 28.8 to 24.3 million years ago; 25.0 million years is tentatively taken as a basal age for known Colhuehuapian. The paleontological hiatus between known Deseadan and known Colhuehuapian is thus in the order of 9.0 million years. Two tuffs from the Santa Cruz Formation (Santacrucian) gave ages of 21.7 and 18.5 million years. Plagioclase and biotite concentrates of an ignimbrite from the Collón Curá Formation (Friasian) gave ages ranging from 15.4 to 14.0 million years.  相似文献   

Using [C]Sodium Bicarbonate to Measure Carbon Dioxide Production in Horses at Rest     

K.L. Urschel  T.L. Smith  R.B. Drake  P.A. Harris  R.J. Geor 《Journal of Equine Veterinary Science》2009

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