Spatial and time variations of the interplanetary microparticle flux analysed from deep space probes pioneers 8 and 9     

J.A.M. Mcdonnell  Otto E. Berg  F.F. Richardson 《Planetary and Space Science》1975,23(1):205-214

The first results of a comprehensive computer analysis of over 300 front film and grid coincidence events is presented using statistical tests on the observed data. The short term time dependence of the observed flux is entirely commensurate with a random Poisson distribution and any possible contributions from discrete “cometary showers” must certainly be of relatively minor significance compared to the sporadic background for mass > 10^?13 g. Periodic seasonal variations of ～ 20 per cent of the average rate are observed common to Pioneers 8 and 9. These variations could reflect on the cometary nature of the source or alternatively indicate the presence of an interstellar component. The mass spectrum of the flux in the range 10^?11?10^?13 g indicates an increasing flux of particles to the lowest limits of mass detected, with a derived flux of Φ = 1·4 × 10^?12m^?0·68 (g) m^?2 sec^?1(2π ster.)^?1.  相似文献   

The Jiddat al Harasis 073 strewn field,Sultanate of Oman     

Edwin GNOS  Silvio LORENZETTI  Otto EUGSTER  A. J. Timothy JULL  Beda A. HOFMANN  Ali Al‐KATHIRI  Manuel EGGIMANN 《Meteoritics & planetary science》2009,44(3):375-387

Abstract— The recently discovered Jiddat al Harasis (JaH) 073 strewn field is the largest found so far in the Sultanate of Oman, covering an area of 19 × 6 km. The 3463 single stones collected range in weight from 52.2 kg down to <1 g (total weight 600.8 kg) and show a pronounced mass sorting. The strewn field shape can be approximated by a NW‐SE‐oriented ellipsoid, indicating an atmospheric entry from SE at a low angle relative to the surface. The meteorite belongs to the L6 ordinary chondrite group and shows S4 average shock grade. Smaller stones generally show a higher weathering grade resulting in a spread from W2 and W4. Enhanced weathering of the stones causing fragmentation after the fall is observed in sandy depressions. Five ¹⁴C measurements on stones of variable size and weathering grade yielded ¹⁴C from 3.8 to 49.9 dpm/kg. Three samples give a ¹⁴C/ ¹⁰Be age consistent with about 14.4 ka. For two samples the cosmogenic, trapped, and radiogenic noble gases were measured. The ratio of the ⁴He and ⁴⁰Ar gas retention ages of 0.29 ± 0.10 and that of the ³He and ²¹Ne cosmic ray exposure ages of 0.36 ± 0.08 Ma indicate that JaH 073 experienced a complex exposure history and lost ⁴He and ⁴⁰Ar due to a major collision. Fragmentation statistics indicate a single major atmospheric disruption and an originally relatively spherical shape of the object. Assuming the material collected represents the majority of fallen mass, and 90–99% of the original weight was lost by ablation, the pre‐atmospheric minimum radius of the meteoroid with density 3.4 g cm^?3would have been at least 75 cm.  相似文献   

Studie über Höhenschwankungen der F2-Schicht: III     

Prof. Dr. Otto Burkard  Dr. Rodolf Eyfrig 《Pure and Applied Geophysics》1950,16(3-4):123-127

Zusammenfassung Es muss unterschieden werden zwischen den (scheinbaren) Minimalhöhen der F2-Schicht und jenen Höhen, in denen sich das Miximum der Elektronenkonzentration befindt. Es wird gezeist, dass sich für Statinen in Aequatornähe diese beiden Gebiete der F2-Schicht ganz verschieden verhalten; aus der Tatsache, dass die untere Begrenzung mit zunehmender Sonnentätigkeit abwts sinkt, während gleichzeitig die Höhe für die maximale Elektronenkonzentration anwächst, wird auf eine Veränderung der Schichtdicke geschlossen, die von der wechselnden Sonnenaktivität étroite avec l'activité solaire.

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Résumé La distinction entre la hauteur virtuelle minimum de la couche F2 et la hauteur vituelle où se trouve le maximum de la concentration 'eléctronique est nécessaire. On Montre que ces deux régions sont tré différentes pour les stations situées près de l'équateur. Etant donné que la base de la couche F2 s'abaisse pendant la période de croissance du cycle solaire, tandis que la hauteur de la concentraion éléctronique du maximmum augmente, on en conclu que l'épaisseur est soumis à des variations en relation étroite avec l'activité solaire.

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Über eine besondere Art von erdmagnetischen Bay-Störungen     

Otto Meyer 《Ocean Dynamics》1951,4(1-2):61-65

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Die Fortschritte in der Erforschung des Meeresbodens durch die schwedische “Albatroß”-Expedition 1947–1948     

Otto Pratje 《Ocean Dynamics》1949,2(4):154-156

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Zwei erdmagnetische Großstörungen     

Otto Meyer 《Ocean Dynamics》1949,2(1-3):100-101

Summary The registrations of two extremely large geomagnetic storms are published, the ionospheric currents being south of Wingst Observatory (53°45 N. lat.).  相似文献   

In memoriam     

H. C. Freiesleben  Arnold Schumacher  Otto Steppes 《Ocean Dynamics》1948,1(1):41-44

Ohne Zusammenfassung  相似文献   

Zur Stratigraphie von Patagonien     

Otto Wilckens 《International Journal of Earth Sciences》1924,15(4):315-317

Ohne Zusammenfassung  相似文献   

Bücher- und Zeitschriftenschau     

H. Stremme  Otto Wilckens  C. Gagel  Steinmann  H. -Ed. Eckstein 《International Journal of Earth Sciences》1921,12(1-2):91-97

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Die Probleme einer Falte     

Otto Jaekel 《International Journal of Earth Sciences》1920,10(4-8):97-111

Ohne Zusammenfassung  相似文献