scholarly journals Massive close binaries and evolutionary synthesis of young starbursts

1999 ◽  
Vol 193 ◽  
pp. 596-597
Author(s):  
Dany Dionne
Keyword(s):  
Magellanic Clouds ◽  
Evolutionary Synthesis ◽  
Close Binaries

With an evolutionary synthesis code, I follow the evolution of a starburst composed of massive close binaries (MCBs) and of single stars at various metallicities. Evolutionary tracks for MCBs have been developed in collaboration with D. Vanbeveren and C. de Loore. The models reproduce the observed WR/O ratio in the Magellanic Clouds.

The Formation of Carbon Stars in the Magellanic Clouds from Mass Transfer in Close Binaries

1999 ◽  
Vol 190 ◽  
pp. 381-382 ◽  
Author(s):  
Ju. Frantsman
Keyword(s):  
Mass Transfer ◽  
Binary Systems ◽  
Magellanic Clouds ◽  
Simulation Technique ◽  
Stage I ◽  
Close Binaries ◽  
Agb Stars ◽  
Carbon Stars ◽  
Population Simulation ◽  
Age Determinations

The presence of the carbon stars in the MC with luminosities higher or lower than predicted for thermally-pulsing (TP) AGB stars, can be explained by processes that happen during the early AGB (E–AGB) stage. I examine this assumption by means of a population simulation technique. I find that there must be TP–AGB C and S stars in the MC that formed as a result of mass transfer in binary systems. Their presence may influence the age determinations of MC clusters.

scholarly journals Seeing Double in the Local Group: Extragalactic Binaries

2005 ◽  
Vol 13 ◽  
pp. 446-446
Author(s):  
Edward F. Guinan
Keyword(s):  
Binary Systems ◽  
Local Group ◽  
Magellanic Clouds ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Major Advance ◽  
Future Expectations ◽  
High Quantum ◽  
Orbital Periods

Photographic surveys of the Magellanic Clouds and the M31 carried decades ago discovered ~200 close binaries. In most cases the photographic light curves are good enough only to identify the stars as close (mostly eclipsing) binaries and to estimate orbital periods and binary type. Except for a few cases, little useful information may be obtained from these stars except to be reassured that eclipsing binary (EB) systems are present in other galaxies. However a major advance occurred with the advent of high quantum efficient CCDs. Because of this an explosion in the number of known extragalactic binaries occurred during the 1990s as offshoots of photometric microlensing surveys such as EROS, MACHO, and OGLE. Now over 10 000 extragalactic EBs have been identified. Also, photometric surveys of M31 and M33 (e.g. DIRECT) are discovering many more 19-20th mag eclipsing/close binaries. Over the next decade it is expected that ~1 million new binary systems will be identified in these galaxies. In this overview I will discuss recent advances and future expectations in the studies of extragalactic binaries

scholarly journals Massive Close Binaries in the Magellanic Clouds

1992 ◽  
Vol 151 ◽  
pp. 497-499
Author(s):  
Virpi S. Niemela ◽  
Lilia P. Bassino
Keyword(s):  
Binary Systems ◽  
Magellanic Clouds ◽  
Close Binaries ◽  
Eclipsing Binary

We present spectroscopic orbits for 4 eclipsing binary systems in the Magellanic Clouds. The minimum masses that we find for the binary components in the LMC are: 34 + 17 M⊙ for HV 2241 and 26 + 15 M⊙ for HV 2543, and for the ones in the SMC: 21 + 25 M⊙ for AzV 73 and 17 + 19 M⊙ for HV 1620.

Novae in the Magellanic Clouds

1979 ◽  
Vol 46 ◽  
pp. 96-101
Author(s):  
J.A. Graham
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
University Of Michigan ◽  
The Past ◽  
Spectroscopic Information ◽  
Objective Prism ◽  
The University ◽  
Small Cloud ◽  
Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).

Revising Plants, man and life: Edgar Anderson reshapes a classic book

2003 ◽  
Vol 30 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Kim Kleinman
Keyword(s):  
Twentieth Century ◽  
Evolutionary Theory ◽  
Evolutionary Synthesis ◽  
Ernst Mayr ◽  
Active Participant ◽  
Evolutionary Mechanism ◽  
Popular Work ◽  
Scientific Attention ◽  
Key Events ◽  
Jesup Lectures

On at least four occasions, Edgar Anderson (1897–1969) began revising his book Plants, man and life (1952). Given both its place in Anderson's career and his place in the development of evolutionary theory in the mid-twentieth century, the emendations are noteworthy. Though a popular work, Plants, man and life served as the distillation of Anderson's ideas on hybridization as an evolutionary mechanism, the need for more scientific attention on domesticated and semi-domesticated plants, and the opportunities such plants provided for the study of evolution. Anderson was an active participant in several key events in what historians have come to call the Evolutionary Synthesis. For example, he and Ernst Mayr shared the 1941 Jesup Lectures on “Systematics and the origin of species”. Anderson's proposed revisions to his book reflect both an attempt to soften certain acerbic comments as well as an attempt to recast the book as a whole.

Introduction: Challenging the Modern Synthesis

2017 ◽  
Author(s):  
Denis M. Walsh ◽  
Philippe Huneman
Keyword(s):  
20Th Century ◽  
Cell Biology ◽  
Population Change ◽  
Modern Synthesis ◽  
Evolutionary Synthesis ◽  
Comparative Biology ◽  
Darwinian Theory ◽  
Modern Evolutionary Synthesis

The modern evolutionary synthesis arose out of the conjunction of the Mendelian theory of inheritance and the neo-Darwinian theory of population change early in the 20th century.1 In the nearly 100 years since its inception, the modern evolutionary synthesis has grown to encompass practically all fields of comparative biology—ecology, ethology, paleontology, systematics, cell biology, physiology, genetics, development. Theodosius Dobzhansky’s dictum—“nothing in biology makes sense except in the light of evolution” (...

Toward a Nonidealist Evolutionary Synthesis

2017 ◽  
Author(s):  
Stuart A. Newman
Keyword(s):  
Evolutionary Theory ◽  
Raw Material ◽  
Evolutionary Synthesis ◽  
Living Systems ◽  
Evolution Of Development ◽  
Search Process ◽  
Physical Processes ◽  
Explanatory Framework ◽  
Material Systems ◽  
Modern Physics

The received model of evolution sees all inherited features resulting from deterministic networks of interacting genes, implying that living systems are reducible to information in genetic programs. The model requires these programs and their associated phenotypes to have evolved by an isotropic search process occurring in gradual steps with no preferred morphological outcomes. The alternative is to recognize that clusters and aggregates of cells, the raw material of evolution, constitute middle-scale material systems. This implies the necessity of bringing the modern physics of mesoscale matter into the explanatory framework for the evolution of development. The relevant, often nonlinear, physical processes were mobilized at the inception of the phyla when their signature morphological outcomes first appeared and remain as efficient causes, albeit transformed, in present-day embryos. This physicogenetic perspective reengages with concepts of saltation, orthogenesis, and environment-induced plasticity long excluded from evolutionary theory.

Why Would We Call for a New Evolutionary Synthesis?

2017 ◽  
Author(s):  
Philippe Huneman
Keyword(s):  
Genotypic Variation ◽  
Modern Synthesis ◽  
Evolutionary Synthesis ◽  
Alternative Scheme ◽  
Random Nature

Considering challenges to the modern synthesis (MS), this chapter reconstructs an explanatory scheme proper to the MS. It contrasts it with the explanatory scheme proper to some alternatives to the MS. It considers which empirical facts should compel us to adopt the alternative scheme, or stand with the MS, or consider a weakly attenuated form of its explanatory scheme. Hence the last section focuses on the form of variation: Given that many findings are accumulating concerning the not purely random nature of variation, it asks which specific patterns of variation would be likely to support an alternative explanatory scheme. It argues that neither biased variation nor random genotypic variation is likely to vindicate a specific explanatory scheme.

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