Astrophysics developments

Shock-compression science, which has developed and matured since its inception in 1955. has never before been documented in book form. Over this period, shock-compression research has provided numerous major contributions to scientific and industrial technology. As a result, our knowledge of geophysics, planetary physics, and astrophysics has substantially improved, and shock processes have become standard industrial methods in materials synthesis and processing. Characterizations of shock-compressed matter have been broadened and enriched with involvements of the fields of physics, electrical engineering, solid mechanics, metallurgy, geophysics, and materials science... 

The second phase, beginning at the end of the nineteenth century, was linked to the development of astrophysics and astrophotography this phase was, however, marked by a decrease in scientific interest in planetary research. 

In which development phase of the universe could there have been the greatest chance of panspermia processes taking place A research group from the Potsdam Institute for Climate Research has tried to provide answers to this difficult question on the basis of research results from astronomy and astrophysics. Using mathematical models, they concluded that the maximum number of habitable planets in our galaxy must have been present at the time when our solar system and the young Earth were evolving (von Bloh et al., 2003). 

Massive stars play an important role in numerous astrophysical contexts that range from the understanding of starburst environments to the chemical evolution in the early Universe. It is therefore crucial that their evolution be fully and consistently understood. A variety of observations of hot stars reveal discrepancies with the standard evolutionary models (see [1] for review) He and N excesses have been observed in O and B main sequence stars and large depletions of B accompanied by N enhancements are seen in B stars and A-F supergiants [2,3,4,5], All of these suggest the presence of excess-mixing, and have led to the development of a new generation of evolutionary models which incorporate rotation (full reviews in [1], [6], [7]). 

How will we identify the extra astrophysics required to reconcile the properties of CDM dark haloes with those of luminous galaxies We can start by developing knowledge of the evolutionary history of at least one place in at least one galaxy. We would be unlucky if that place were far from the norm alternatively, any theory that predicts such a history to be very unusual might be suspect -the galaxian Copernican principle. Kinematics and current spatial location are of course critical parameters, so that traditional stellar populations analyses are... 

This type of 3He refrigerator was developed for astrophysical measurements in the far infrared on board of stratospheric balloons, rockets [23] and aeroplanes and also for ground-based telescopes [24],... 

LTE line-blanketed models and spectrum synthesis programs for stars hotter than reff = 5500 K are under continuing development by R. L. Kurucz at the Smithsonian Astrophysical Observatory, Cambridge, Mass., and available from their author in CD-Rom or on his website http //kurucz.harvard.edu/. 

In this textbook many exciting topics in astrophysics and cosmology are covered, from abundance measurements in astronomical sources, to light element production by cosmic rays and the effects of galactic processes on the evolution of the elements. Simple derivations for key results are provided, together with problems and helpful solution hints, enabling the student to develop an understanding of results from numerical models and real observations. 

Lithium is an element of interest in astrophysics, owing to the marked variations in Li abundance and isotopic composition of materials emanating from different sources in the cosmos. The development of the terrestrial or Solar system Li isotopic compositions, which, to the limit of our current rmderstanding, are quite different from values predicted for nucleosynthetic or interstellar Li, remains a puzzle for active astronomical research. 

The heart of the polarization-modulated nephelometer is a photoelastic modulator, developed by Kemp (1969) and by Jasperson and Schnatterly (1969). The latter used their instrument for ellipsometry of light reflected by solid surfaces (the application described here could be considered as ellipsometry of scattered light). Kemp first used the modulation technique in laboratory studies but soon found a fertile field of application in astrophysics the modulator, coupled with a telescope, allowed circular polarization from astronomical objects to be detected at much lower levels than previously possible. 

He made major contributions to electrochemistry, thermodynamics, and photochemistry. Nernsfs early studies in electrochemistry were inspired by Arrhenius dissociation theory which first recognized the importance of ions in solution His heat theorem, known as the Third Law of Thermodynamics, was developed in 1906. In 1918 his studies of photochemistry led him to his atom chain reaction theory. In laoer years, he occupied himself with astrophysical theories, a field in w hich the heat theorem had important applications. 

For many reasons atomic spectroscopy continues to be one of the most rapidly developing branches of physics. This is primarily due to the creation of very stable and monochromatic lasers, allowing one to selectively excite various atomic states, to create very highly excited (Rydberg) atoms, and due to the occurrence of new possibilities, given by non-atmospheric astrophysics, which allow one to register the electromagnetic radiation... 

Utilization of data obtained from various plasma sources (e.g. beam-foil, tokamak and laser-produced plasma [287]) enabled the identification with high accuracy of the lines of highly ionized atoms in solar spectra. A special commision No 14 on Atomic and Molecular Data of the International Astronomical Union coordinates the activity on systematization of spectroscopic data, informs the astrophysics community on new developments and provides assessments and recommendations. It also provides reports which highlight these new developments and list all important recent literature references on atomic spectra and wavelength standards, energy level analyses, line classifications, compilations of laboratory data, databases and bibliographies. 

The interpretation of the intensities of lines observed in astrophysical sources requires a wide variety of reliable atomic and, to a lesser extent, molecular data [1]. Also, the steady development of high temperature plasmas, in relation to the fusion programmes ongoing in several countries, has given rise to a considerable interest in the spectroscopy ofheavy and/or highly ionised atoms [2], The spectacular advance of some experimental techniques has not diminished the need for reliable theoretical data. In the production of spectroscopic quantities such as oscillator strengths to fulfill the present demands of both the astrophysics and plasma physics communities, several authors [3-5] have emphasised the need for both experimentalists and theoreticians to self-assess the data they supply. 

Element abundance data were useful not only in astrophysics and cosmology but also in the attempts to understand the structure of the atomic nucleus. [74] As mentioned, this line of reasoning was adopted by Harkins as early as 1917, of course based on a highly inadequate picture of the nucleus. It was only after 1932, with the discovery of the neutron as a nuclear component, that it was realized that not only is the atomic mass number related to isotopic abundance, but so are the proton and neutron numbers individually. Cosmochemical data played an important part in the development of the shell model, first proposed by Walter Elsasser and Kurt Guggenheimer in 1933-34 but only turned into a precise quantitative theory in the late 1940s. [75] Guggenheimer, a physical chemist, used isotopic abundance data as evidence of closed nuclear shells with nucleon numbers 50 and 82. 

Henrietta Swan Leavitt, http //hoa.aavso.org/posterswan.htm (This web page is part of Hands-On Astrophysics, an AAVSO educational project developed with funds from the National Science Foundation. AAVSO is an acronym for American Association of Variable Star Observers.)... 

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