Stellar Evolution

1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild
Keyword(s):  
Solar System ◽  
Stellar Evolution ◽  
Space Craft ◽  
New Techniques ◽  
Substantial Body ◽  
Individual Stars ◽  
The Past ◽  
Evolution Of Galaxies ◽  
History Of ◽  
Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

scholarly journals A Brief History of the Study of Nearby Young Moving Groups and Their Members

2015 ◽  
Vol 10 (S314) ◽  
pp. 16-20
Author(s):  
Joel H. Kastner
Keyword(s):  
Stellar Evolution ◽  
Main Sequence ◽  
Protoplanetary Disks ◽  
Individual Stars ◽  
The Past ◽  
History Of ◽  
Moving Groups

AbstractBeginning with the enigmatic (and now emblematic) TW Hya, the scutiny of individual stars and star-disk systems has both motivated and benefitted from the identification of nearby young moving groups (NYMGs). I briefly outline the emergence of this relatively new subfield of astronomy over the past two decades, and offer a few examples illustrating how the study of NYMGs and their members enables unique investigations of pre-main sequence stellar evolution, evolved protoplanetary disks, and young exoplanets.

scholarly journals The Evolution of Mathematics in Ancient China: From the newly discovered 數 Shu and 算數書 Suan Shu Shu Bamboo Texts to the Nine Chapters on the Art of Mathematics

2020 ◽  
Vol 19 (37) ◽  
pp. 25-78
Author(s):  
Joseph W. Dauben
Keyword(s):  
History Of Mathematics ◽  
Plenary Lecture ◽  
Ancient China ◽  
New Techniques ◽  
Tsinghua University ◽  
Warring States ◽  
The Past ◽  
Peking University ◽  
History Of ◽  
Mathematical Texts

The history of ancient Chinese mathematics and its applications has been greatly stimulated in the past few decades by remarkable archaeological discoveries of texts from the pre-Qin and later periods that make it possible to study in detail mathematical material from the time at which it was written. By examining the recent Warring States, Qin and Han bamboo mathematical texts currently being conserved and studied at Tsinghua University and Peking University in Beijing, the Yuelu Academy in Changsha, and the Hubei Museum in Wuhan, it is possible to shed new light on the history of early mathematical thought and its applications in ancient China. Also discussed here are developments of new techniques and justifications given for the problems that were a significant part of the growing mathematical corpus, and which eventually culminated in the comprehensive Nine Chapters on the Art of Mathematics. What follows is a revised text of an invited plenary lecture given during the 10th National Seminar on the History of Mathematics at UNICAMP in Campinas, SP, Brazil, on March 27, 2013.

scholarly journals Hydrogen molecular ions and the violent birth of the Solar System

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180403 ◽  
Author(s):  
Cecilia Ceccarelli ◽  
Cecile Favre ◽  
Ana López-Sepulcre ◽  
Francesco Fontani
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Past History ◽  
Classical Problem ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Molecular Ions ◽  
Observational Constraints ◽  
The Past ◽  
History Of

Many pieces of evidence indicate that the Solar System youth was marked by violent processes: among others, high fluxes of energetic particles (greater than or equal to 10 MeV) are unambiguously recorded in meteoritic material, where an overabundance of the short-lived 10 Be products is measured. Several hypotheses have been proposed to explain from where these energetic particles originate, but there is no consensus yet, mostly because of the scarcity of complementary observational constraints. In general, the reconstruction of the past history of the Solar System is best obtained by simultaneously considering what we know of it and of similar systems nowadays in formation. However, when it comes to studying the presence of energetic particles in young forming stars, we encounter the classical problem of the impossibility of directly detecting them toward the emitting source (analogously to what happens to galactic cosmic rays). Yet, exploiting the fact that energetic particles, such as cosmic rays, create H 3 + and that an enhanced abundance of H 3 + causes dramatic changes on the overall gas chemical composition, we can indirectly estimate the flux of energetic particles. This contribution provides an overview of the search for solar-like protostars permeated by energetic particles and the discovery of a protocluster, OMC-2 FIR4, where the phenomenon is presently occurring. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

scholarly journals Diogenes of Oenoanda on Cyrenaic Hedonism

2002 ◽  
Vol 48 ◽  
pp. 159-174
Author(s):  
David Sedley
Keyword(s):  
Roman Empire ◽  
Good Reason ◽  
Second Century ◽  
Ancient World ◽  
Substantial Body ◽  
The Past ◽  
History Of ◽  
Exciting Time

One of the reasons why the past three decades have been an exciting time for historians of Epicureanism has been the revival of work on the Herculaneum papyri – very much a team effort. But another equally good reason has been provided by a remarkable solo act, Martin Ferguson Smith's pioneering work on the second-century AD Epicurean inscription of Diogenes of Oenoanda – the largest of all Greek inscriptions to survive from the ancient world, a key text in the history of Epicurean philosophy, and an extraordinary snapshot of the (literally) monumental scale on which philosophical evangelism could be practised in the Roman empire.Smith has, almost single-handed, discovered and edited well over 100 new fragments of the inscription. This enabled him in 1993 to publish his comprehensive edition of the augmented inscription. But that was not the end of his labours. Returning to the site of Oenoanda, he has unearthed a substantial body of new ‘new fragments’, and has hopes of uncovering more in future seasons. A recent batch was published in a 1998 article. In this paper I want to consider just one of them, New Fragment 128, which fills a hole in the existing fr. 33 of Smith's edition. Thanks to this discovery, Smith has been able to supply the line-ends of the missing col. IV, and likewise to join the previously lost line-beginnings of col. V to the already surviving line-ends of that column. In addition, he has been able to make very convincing improvements to his previous readings of column III.

scholarly journals 15. Physical Study of Comets, Minor Planets and Meteorites

1979 ◽  
Vol 17 (1) ◽  
pp. 73-102
Author(s):  
N.B. Richter
Keyword(s):  
Solar System ◽  
Considerable Increase ◽  
Solar Nebula ◽  
Past History ◽  
Minor Planets ◽  
The Past ◽  
Physical Study ◽  
History Of

Comets, minor planets and meteorites provide us with valuable information about the past history of the solar system. They belong to the most primitive samples of the primordial solar nebula. Over the past years, we can record a considerable increase of interest in these bodies.

The record of solar and galactic radiations in the ancient lunar regolith and their implications for the early history of the Sun and Moon

1977 ◽  
Vol 285 (1327) ◽  
pp. 587-592 ◽  
Keyword(s):  
Solar Wind ◽  
Solar Flare ◽  
Solar Flares ◽  
Lunar Regolith ◽  
Galactic Cosmic Rays ◽  
Flare Activity ◽  
New Techniques ◽  
The Past ◽  
History Of ◽  
Individual Grains

A variety of techniques are available for studying past variations of solar wind, solar flares, galactic cosmic rays, and micrometeorites. Lumar rock results which average over the recent past ( ~ 10 Ma) indicate no major changes in any of these components. At longer times, recent data suggest secular changes in the 15N/14N ratio in the solar wind, possibly due to enhanced solar flare activity. With the deployment of new techniques, it now appears possible to measure solar wind, solar flare, and micrometeorite records in individual grains removed from different layers of lunar cores. Such grains have been exposed for brief intervals of time (103-104 a) for times extending at least 109 a in the past. Lunar and meteoritic breccias are promising candidates for extending the record back still further, perhaps close to the beginning of the solar system.

International Diffusion of Agrarian Technology

1974 ◽  
Vol 34 (1) ◽  
pp. 51-73 ◽  
Author(s):  
Robert Evenson
Keyword(s):  
Agricultural Change ◽  
New Techniques ◽  
International Diffusion ◽  
Central Focus ◽  
The Past ◽  
History Of ◽  
Development Agencies

Improved techniques of production have been an important part of the history of agricultural change in all modern economies. The search for policies to bring about the rapid introduction of improved techniques of production in traditional or less developed agricultural sectors has been a central focus of development agencies for the past two decades. It has proven to be a very difficult task, however, to develop policies which actually achieve the transfer of new techniques. The record of success in development efforts towards this end in agriculture has been, on the whole, rather poor.

scholarly journals Something to Sing About: A Preliminary List of Canadian Staged Dramatic Music Since 1867

2008 ◽  
Vol 28 (1) ◽  
pp. 14-77 ◽  
Author(s):  
Mary I. Ingraham
Keyword(s):  
Historical Documents ◽  
Systematic Research ◽  
Cultural Activity ◽  
Political Values ◽  
Substantial Body ◽  
Cultural Artifact ◽  
The Past ◽  
History Of ◽  
Dramatic Music

Abstract The primary aim of this article is to introduce and present a preliminary list of Canadian staged dramatic music composed between 1867 and 2007 as a contribution to a previously under-cultivated field of Canadian cultural activity and research. More than simply an exercise in establishing a repertoire, this article approaches these works as important historical documents that articulate contemporaneous cultural, social, and political values over the past 140 years. Through a discussion of issues raised in determining genre and musical citizenship, the scope, nature, and history of these works lays a foundation for systematic research into this most important Canadian cultural artifact. To facilitate access to what is a substantial body of information, this preliminary list is offered in three formats: 1) alphabetically by composer’s surname; 2) alphabetically by the title of the work; and 3) chronologically by date of completion of the work. Compositions are identified across all formats by a Preliminary Ingraham Number (PIN) comprised of the composer’s surname and the date of completion of the work.

scholarly journals Constraining the Evolutionary History of the Moon and the Inner Solar System: A Case for New Returned Lunar Samples

2019 ◽  
Vol 215 (8) ◽  
Author(s):  
Romain Tartèse ◽  
Mahesh Anand ◽  
Jérôme Gattacceca ◽  
Katherine H. Joy ◽  
James I. Mortimer ◽  
...  
Keyword(s):  
Solar System ◽  
Large Scale ◽  
Lunar Regolith ◽  
The Moon ◽  
Planetary Body ◽  
The Past ◽  
Lunar Samples ◽  
History Of ◽  
Magma Oceans ◽  
Robotic Missions

AbstractThe Moon is the only planetary body other than the Earth for which samples have been collected in situ by humans and robotic missions and returned to Earth. Scientific investigations of the first lunar samples returned by the Apollo 11 astronauts 50 years ago transformed the way we think most planetary bodies form and evolve. Identification of anorthositic clasts in Apollo 11 samples led to the formulation of the magma ocean concept, and by extension the idea that the Moon experienced large-scale melting and differentiation. This concept of magma oceans would soon be applied to other terrestrial planets and large asteroidal bodies. Dating of basaltic fragments returned from the Moon also showed that a relatively small planetary body could sustain volcanic activity for more than a billion years after its formation. Finally, studies of the lunar regolith showed that in addition to containing a treasure trove of the Moon’s history, it also provided us with a rich archive of the past 4.5 billion years of evolution of the inner Solar System. Further investigations of samples returned from the Moon over the past five decades led to many additional discoveries, but also raised new and fundamental questions that are difficult to address with currently available samples, such as those related to the age of the Moon, duration of lunar volcanism, the lunar paleomagnetic field and its intensity, and the record on the Moon of the bombardment history during the first billion years of evolution of the Solar System. In this contribution, we review the information we currently have on some of the key science questions related to the Moon and discuss how future sample-return missions could help address important knowledge gaps.

Cosmic Archaeology

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
Interstellar Space ◽  
Human Society ◽  
The Past ◽  
History Of ◽  
Habitable Planet

This chapter discusses the process of how the solar system had to take form from the near nothingness of interstellar space. Scientists pondering the history of the solar system are much like archaeologists sifting through the sands of Egypt. They bring different methods and tools to the job, but both strive to glean as much as possible from precious relics from the past, and combine this with information deduced from the current surroundings. Deciphering the history of the solar system is archaeology on a grand scale. For human society to arise, species needed to evolve from those that went before. Prior to this, life had to appear on a suitably habitable planet orbiting a long-lived star.

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