Blue straggler production in globular clusters     

Melvyn B. Davies  Giampaolo Piotto  Francesca De Angeli 《Monthly notices of the Royal Astronomical Society》2004,349(1):129-134

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Compact Groups of Galaxies: Evolution of the Stellar Population     

I. García De La Rosa  R. Coziol  R.R. De Carvalho  S. Zepf 《Astrophysics and Space Science》2001,276(2-4):717-723

We present a study focusing on the nature of compact groups (CGs) through the study of their elliptical (E) galaxies. Parameters describing the internal dynamics and the stellar populations of the galaxies are compared with their counterparts in other environments. Our sample has24 bright E galaxies located in the core of Hickson CGs and 11 bright ‘bona fide’ Es, located in the field or very loose groups. Their spectra were obtained with the 2.1 m Telescope at KPNO and have a 4.1 Å resolution over the wavelength range 3500–7000 Å. We have found that, from the dynamical point of view, E galaxies in CGs are essentially similar to those in dense clusters. Moreover, the stellar populations of Es in CGs seem to be older and less metal rich than those in the field, behaviour which has also been observed by Rose et al. (1994).  相似文献   

On the applicability of Goldberg and Unno's method to the determination of microturbulent velocities in an atmosphere with convection     

C. De Jager  L. Neven 《Solar physics》1972,22(1):49-52

The method of Goldberg and Unno for the determination of microturbulent velocities in a stellar atmosphere is only applicable if there are no macroturbulent or convective motions.If such motions occur, as in the solar photosphere, the derived results are false and may lead to misinterpretations such as an increase of the microturbulent velocity with depth or anisotropic microturbulence.  相似文献   

On the evolutionary time scale of the accreting component in massive close binaries     

C. Doom  J. P. De Grève 《Astrophysics and Space Science》1981,80(2):369-395

The remaining core hydrogen burning lifetime after mass exchange is computed for the mass gaining component in massive close binary systems. Results are obtained for various modes of mass accretion, for a wide range of initial masses and mass ratios, and for different values of mass loss from the system. The effect of mass loss by stellar wind is included. By use of general properties of massive close binary evolution, the position in time of four events is determined: the end of core hydrogen burning of the primary and the secondary, and the occurrence of the supernova of the primary and the secondary. It is found that the two supernova event occur rather close in time, compared to the Main Sequence time scales of the components.This research is supported by the National Foundation of Collective Fundamental Research of Belgium (FKFO) under No. 2.9009.79.  相似文献   

Statistics of apparent distances between QSO's and bright galaxies     

R. Kippenhahn  H. L. De Vries 《Astrophysics and Space Science》1974,26(1):131-135

Two experiments with points randomly distributed over the sky were carried out in order to check the significance of the apparent associations between bright galaxies and quasistellar objects found by Burbidgeet al. (1971). The experiments confirm the statistical relevance of these associations.  相似文献   

Solar radio spectra between 160 and 320 MHz     

T. De Groot 《Solar physics》1970,14(1):176-189

Dynamic spectra of incremental solar radio emission reveal that (mostly faint) pulsating and morphologically similar structures, including patterns of bright spots, dominate between ca. 250 and 320 MHz. As individual bursts these bright spots are similar to Type I bursts but they appear in an entirely different environment. This kind of activity is indicative of Type IV emission and seems to favour the generation of Type III bursts. Often its boundary with storm activity at the lower side of the band is rather sharp.  相似文献   

Note on solar hard X-ray bursts     

C. De Jager 《Solar physics》1967,2(3):347-350

Observationally solar X bursts fall into three different categories : soft X bursts (E < 10 keV), deka-keV bursts (10–150 keV), and very hard X bursts or deci-MeV bursts (200–1000 keV). The first kind is quasi-thermal, the last kind is non-thermal. The real existence of the third kind of burst looks probable but has not yet been proved by direct observations. The difference between deci-MeV and deka-keV bursts may mainly be a matter of geometry of the emitting plasma.  相似文献   

Source functions in the cores of infrared Fraunhofer lines     

C. De Jager  L. Neven 《Solar physics》1968,3(1):159-163

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Editorial     

C. De Jager  Z. vestka 《Solar physics》1968,3(1):3

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Relief and Gravity Anomalies Over a Convecting Mantle     

Jean-Claude De Bremaecker 《Geophysical Journal International》1976,45(2):349-356

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