Author: T. L. Cline
Publisher:
ISBN:
Category : Gamma ray astronomy
Languages : en
Pages : 20

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Book Description

Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1990

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Book Description

Author: U.S. National Aeronautics and Space Administration
Publisher:
ISBN:
Category :
Languages : en
Pages : 648

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Book Description

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 32

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Book Description

Author: United States. Superintendent of Documents
Publisher:
ISBN:
Category : United States
Languages : en
Pages : 1284

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Book Description

Author: United States. Superintendent of Documents
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1284

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Book Description

Author: F. Matteucci
Publisher: Springer Science & Business Media
ISBN: 9780792366799
Category : Medical
Languages : en
Pages : 644

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Book Description
This review of the most up-to-date observational and theoretical information concerning the chemical evolution of the Milky Way compares the abundances derived from field stars and clusters, giving information on the abundances and dynamics of gas.

Author: Roland Diehl
Publisher: Springer Science & Business Media
ISBN: 3642126979
Category : Science
Languages : en
Pages : 577

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Book Description
This book introduces the reader to the field of nuclear astrophysics, i.e. the acquisition and reading of measurements on unstable isotopes in different parts of the universe. The authors explain the role of radioactivities in astrophysics, discuss specific sources of cosmic isotopes and in which special regions they can be observed. More specifically, the authors address stars of different types, stellar explosions which terminate stellar evolutions, and other explosions triggered by mass transfers and instabilities in binary stars. They also address nuclear reactions and transport processes in interstellar space, in the contexts of cosmic rays and of chemical evolution. A special chapter is dedicated to the solar system which even provides material samples. The book also contains a description of key tools which astrophysicists employ in those particular studies and a glossary of key terms in astronomy with radioactivities.

Author: Willem Wamsteker
Publisher: Springer Science & Business Media
ISBN: 9780792325277
Category : Science
Languages : en
Pages : 794

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Book Description
ROSAT Observations G. HASINGER Max-Planck-Institut flir extraterrestrische Physik, D-85740 Garching, Germany Abstract. This review describes the most recent advances in the study of the extragalactic soft X-ray background and what we can learn about its constituents. The deepest pointed observations with the ROSAT PSPC are discussed. The logN-logS relation is presented, which reaches to the faintest X-ray fluxes and to the highest AGN surface densities ever achieved. The N(>S) relation shows a 2 density in excess of 400 deg- at the faintest fluxes and a flattening below the Einstein Deep Survey limit. About 60% of the extragalactic background has been resolved in the deepest field. Detailed source spectra and first optical and radio identifications will be discussed. The results are put into perspective of the higher energy X -ray background. Key words: X-rays, background radiations, active galactic nuclei. 1. Introduction The extragalactic X-ray background (XRB), discovered about 30 years ago, has been studied extensively with many X-ray experiments, in particular with the satel lites HEAO I and II (see ego Boldt 1987) and with ROSAT (e. g. Hasinger et aI. , 1993). Figure 1 shows a compilation of some of the most recent spectral measure ments for the X-ray background. Over the energy range from 3 to about 100 keY its spectrum can be well approximated by an optically thin thermal bremsstrahlung model with kT ~ 40 keY, while at lower X-ray energies a steepening into a new component has been observed observed (e. g.

Author: Justin Filiberto
Publisher: Elsevier
ISBN: 012804201X
Category : Science
Languages : en
Pages : 427

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Book Description
Volatiles in the Martian Crust is a vital reference for future missions - including ESA's EXO Mars and NASA's Mars2020 rover - looking for evidence of life on Mars and the potential for habitability and human exploration of the Martian crust. Mars science is a rapidly evolving topic with new data returned from the planet on a daily basis. The book presents chapters written by well-established experts who currently focus on the topic, providing the reader with a fresh, up-to-date and accurate view. Organized into two main sections, the first half of the book focuses on the Martian meteorites and specific volatile elements. The second half of the book explores processes and locations on the crust, including what we have learned about volatile mobility in the Martian crust. Coverage includes data from orbiter and in situ rovers and landers, geochemical and geophysical modeling, and combined data from the SNC meteorites. - Presents information about the nature, relationship, and reactivity of chemical elements and compounds on Mars - Explores the potential habitability of Mars - Provides a comprehensive view of volatiles in the Martian crust from studies of actual samples as well as from the variety of landed missions, including the MER and Curiosity rovers - Delivers a vital reference for ongoing and future missions to Mars while synthesizing large data sets and research on volatiles in the Martian atmosphere - Concludes with an informative summary chapter that looks to future Mars missions and what might be learned