A non-main-sequence secondary in SY Cancri     

Robert Connon Smith  Otto Mehes  Dave Vande Putte  Nigel A. Hawkins 《Monthly notices of the Royal Astronomical Society》2005,360(1):364-374

Simultaneous spectroscopic and photometric observations of the Z Cam type dwarf nova SY Cancri were used to obtain absolute flux calibrations. A comparison of the photometric calibration with a wide-slit spectrophotometric calibration showed that either method is equally satisfactory. A radial velocity study of the secondary star, made using the far-red Na  i doublet, yielded a semi-amplitude of   K ₂= 127 ± 23 km s⁻¹  . Taking the published value of  86 ± 9 km s⁻¹  for K ₁ gives a mass ratio of   q = M ₂/ M ₁= 0.68 ± 0.14  ; this is very different from the value of  1.13 ± 0.35  quoted in the literature. Using the new lower mass ratio, and constraining the mass of the white dwarf to be within reasonable limits, then leads to a mass for the secondary star that is substantially less than would be expected for its orbital period if it satisfied a main-sequence mass–radius relationship. We find a spectral type of M0 that is consistent with that expected for a main-sequence star of the low mass we have found. However, in order to fill its Roche lobe, the secondary must be significantly larger than a main-sequence star of that mass and spectral type. The secondary is definitely not a normal main-sequence star.  相似文献   

Physical properties of rocks. Fundamentals and principles of petrophysics: by J.H. Schön. (Handbook of Geophysical Exploration, Seismic Exploration, Klaus Helbig and Sven Treitel (Editors), Volume 18). Pergamon Press, London, 1996. Hardcover, xvi + 583 pp., Dfl. 267.-, ISBN 0 08 04 10081     

António Correia 《Journal of Applied Geophysics》1997,36(4):221-222

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The Richfield LL3 chondrite     

Alan E. RUBIN  Paul BENOIT  Blaine REED  Otto EUGSTER  Ernst POLNAU 《Meteoritics & planetary science》1996,31(6):925-927

Abstract— Richfield is a moderately shocked (shock stage S4) LL3.7 genomict breccia find consisting mainly of light-colored recrystallized clasts and dark clasts exhibiting significant silicate darkening; a few impact-melt-rock clasts and LL5 chondrite clasts also occur. The cosmic-ray exposure age of 14.5 Ma is indistinguishable from the main exposure peak for LL chondrites (15 Ma). Although the exposure ages indicate little He loss, the gas-retention ages indicate high gas losses that must have occurred prior to or during ejection from the LL parent body.  相似文献   

On the Use of Random Material in Dam Cores: Case of the Manso Dam,Brazil     

Ferreira  Breno S.  Almeida  Marcio S. S.  Lopes  Francisco R.  Reis Cavalcanti  Maria do Carmo  Pires Filho  Celso José 《Geotechnical and Geological Engineering》2022,40(4):1973-1987

Geotechnical and Geological Engineering - The Manso Dam, in the Brazilian State of Mato Grosso, intended for flood control and electricity generation, was built by a state-owned energy company in...  相似文献   

Stratigraphie und Bau von Neu-Caledonien     

Otto Wilckens 《International Journal of Earth Sciences》1925,16(2):128-142

Ohne Zusammenfassung  相似文献   

Long term evolution and chaotic diffusion of the insolation quantities of Mars   总被引：1，自引：0，他引：1  

J. Laskar  A.C.M. Correia  M. Gastineau  B. Levrard 《Icarus》2004,170(2):343-364

As the obliquity of Mars is strongly chaotic, it is not possible to give a solution for its evolution over more than a few million years. Using the most recent data for the rotational state of Mars, and a new numerical integration of the Solar System, we provide here a precise solution for the evolution of Mars' spin over 10 to 20 Myr. Over 250 Myr, we present a statistical study of its possible evolution, when considering the uncertainties in the present rotational state. Over much longer time span, reaching 5 Gyr, chaotic diffusion prevails, and we have performed an extensive statistical analysis of the orbital and rotational evolution of Mars, relying on Laskar's secular solution of the Solar System, based on more than 600 orbital and 200,000 obliquity solutions over 5 Gyr. The density functions of the eccentricity and obliquity are specified with simple analytical formulas. We found an averaged eccentricity of Mars over 5 Gyr of 0.0690 with standard deviation 0.0299, while the averaged value of the obliquity is 37.62° with a standard deviation of 13.82°, and a maximal value of 82.035°. We find that the probability for Mars' obliquity to have reached more than 60° in the past 1 Gyr is 63.0%, and 89.3% in 3 Gyr. Over 4 Gyr, the position of Mars' axis is given by a uniform distribution on a spherical cap limited by the obliquity 58.62°, with the addition of a random noise allowing a slow diffusion beyond this limit. We can also define a standard model of Mars' insolation parameters over 4 Gyr with the most probable values 0.068 for the eccentricity and 41.80° for the obliquity.  相似文献   

Die regionale Geologie im Hochschulunterricht     

Otto Wilckens 《International Journal of Earth Sciences》1913,4(3):207-209

Ohne Zusammenfassung  相似文献   

400 Jahre Mathematik und Astronomie an der Universität Würzburg: Alma Julia Herbipolensis 1582–1982     

Otto Volk 《Celestial Mechanics and Dynamical Astronomy》1982,28(1-2):243-250

Ohne Zusammenfassung

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400 years mathematics and astronomy at the Wurzburg University: Alma Julia herbipolensis 1582–1982

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s. O. Volk, Mathematik, Astronomie und Physik in der Vergangenheit der Universität Würzburg, Festschrift 1982.

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Paper presented at the 1981 Oberwolfach Conference on Mathematical Methods in Celestial Mechanics.  相似文献   

A hydrodynamic pulsation model under subharmonic resonance     

Toshiki Aikawa  Otto Bruegman 《Astrophysics and Space Science》1987,137(1):115-127

We found a hydrodynamic pulsation model of yellow supergiants under subharmonic resonance. It is confirmed that the feature of pulsation by the resonance is long-lived in the model by performing the hydrodynamical simulation for a long time.  相似文献   

Einiges zur Geometrie der Lagekugelbesetzung     

Otto Mellis 《Mineralogy and Petrology》1954,4(1-4):138-144

Ohne ZusammenfassungMit 3 Textabbildungen.  相似文献