Gravitational waves

2021 ◽  
pp. 65-92
Author(s):  
Andrew M. Steane
Keyword(s):  
Gravitational Waves ◽  
Binary Stars ◽  
Wave Amplitude ◽  
Binary Star ◽  
Gravitational Wave Detector ◽  
Compact Source ◽  
Wave Solutions ◽  
Physical Insight ◽  
The Impact ◽  
Laser Interferometric

The theory of weak gravitational waves is discussed at length. The transverse traceless gauge is described, and the behaviour of plane wave solutions obtained. The impact of a wave on physical objects, and hence methods for their detection, are calculated. The laser interferometric gravitational wave detector is described. Sources such as binary stars are considered. The compact source approximation is employed, and the quadrupole formula relating the wave amplitude to the quadrupole of the source is obtained. Energy flux in gravitational waves is calculated by two methods, one more general, the other giving further physical insight. The total emitted power is obtained. These are lengthy calculations but they are presented in full. Finally they are applied in detail to a binary star with elliptical orbtis (the Hulse Taylor binary) and to a black hole merger detected by the LIGO interferometers.

scholarly journals Dawes Review 6: The Impact of Companions on Stellar Evolution

2017 ◽  
Vol 34 ◽  
Author(s):  
Orsola De Marco ◽  
Robert G. Izzard
Keyword(s):  
Stellar Evolution ◽  
Binary Stars ◽  
Binary Star ◽  
Luminous Blue Variables ◽  
James Webb Space Telescope ◽  
Type Ia ◽  
Ia Supernovae ◽  
New Phenomena ◽  
The Impact

AbstractAstrophysicists are increasingly taking into account the effects of orbiting companions on stellar evolution. New discoveries have underlined the role of binary star interactions in a range of astrophysical events, including some that were previously interpreted as being due uniquely to single stellar evolution. We review classical binary phenomena, such as type Ia supernovae, and discuss new phenomena, such as intermediate luminosity transients, gravitational wave-producing double black holes, and the interaction between stars and their planets. Finally, we reassess well-known phenomena, such as luminous blue variables, in light of interpretations that include both single and binary stars. At the same time we contextualise the new discoveries within the framework of binary stellar evolution. The last decade has seen a revival in stellar astrophysics as the complexity of stellar observations is increasingly interpreted with an interplay of single and binary scenarios. The next decade, with the advent of massive projects such as the Square Kilometre Array, the James Webb Space Telescope, and increasingly sophisticated computational methods, will see the birth of an expanded framework of stellar evolution that will have repercussions in many other areas of astrophysics such as galactic evolution and nucleosynthesis.

scholarly journals Gravitational waves observation: brief comments

2016 ◽  
Vol 38 (4) ◽  
Author(s):  
Mauro Cattani ◽  
José Maria Filardo Bassalo
Keyword(s):  
Black Holes ◽  
Gravitational Waves ◽  
United States Of America ◽  
Laser Interferometer ◽  
Binary Star ◽  
The United States ◽  
Basic Principles ◽  
Interferometric Technique ◽  
Relativistic Approach ◽  
Laser Interferometric

In preceding papers we have shown the fundamental aspects of the General Relativity (GR), of the emission and detection of gravitational waves (GW). With the same objective we analyze the two recent observations of the GW done by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States of America. These GW observations known as the GW150914 and GW151226 events are emitted by binary-star systems of black-holes (BBH). We present the basic principles of the laser interferometric technique that today is considered as the only one able to detect with certainty the GW. Using a simple relativistic approach we explain approximately the observed GW in the spiral stage.

scholarly journals The symbiotics as binary stars

1982 ◽  
Vol 70 ◽  
pp. 231-251
Author(s):  
Mirek J. Plavec
Keyword(s):  
Mass Transfer ◽  
Binary Stars ◽  
Binary Star ◽  
Evolutionary Stage ◽  
Cool Component ◽  
Second Stage ◽  
Star Evolution ◽  
Red Giant ◽  
Helium Star ◽  
Central Stars

AbstractSymbiotic stars have become an important testing ground of various theories of binary star evolution. Several physically different models can explain them, but in each case certain fairly restrictive conditions must be met, so if we manage to identify a definite object with a model, it will tell us a lot about the structure and evolutionary stage of the stars involved. I envisage at least three models that can give us a symbiotic object: I have called them, respectively, the PN symbiotic, the Algol symbiotic, and the novalike symbiotic. Their properties are briefly discussed. The most promising model is one of a binary system in the second stage of mass transfer, actually at the beginning of it: The cool component is a red giant ascending the asymptotic branch, expanding but not yet filling its critical lobe. The hot star is a subdwarf located in the same region of the Hertzsprung-Russell diagram as the central stars of planetary nebulae. It may be closely related to them, or it may be a helium star, actually a remnant of an Algol primary which underwent the first stage of mass transfer. In these cases, accretion on this star may not play a significant role (PN symbiotic).

scholarly journals A binary star formation mechanism through the fragmentation of prolate dense cores rotating end over end

1991 ◽  
Vol 147 ◽  
pp. 526-528
Author(s):  
Hans Zinnecker
Keyword(s):  
Star Formation ◽  
Formation Mechanism ◽  
Binary Stars ◽  
Binary Star ◽  
Initial Structure ◽  
Eccentric Orbit ◽  
Dense Cores ◽  
Molecular Core ◽  
Low Mass

I propose and briefly elaborate on a major new mechanism for the formation of wide, low-mass binary stars: the fragmentation of a collapsing, initially elongated dense molecular core rotating end over end. This initial structure will develop into two independent gravitationally bound stellar condensations orbiting each other in a rather eccentric orbit.

scholarly journals A binary star formation mechanism through the fragmentation of prolate dense cores rotating end over end

1991 ◽  
Vol 147 ◽  
pp. 526-528
Author(s):  
Hans Zinnecker
Keyword(s):  
Star Formation ◽  
Formation Mechanism ◽  
Binary Stars ◽  
Binary Star ◽  
Initial Structure ◽  
Eccentric Orbit ◽  
Dense Cores ◽  
Molecular Core ◽  
Low Mass

I propose and briefly elaborate on a major new mechanism for the formation of wide, low-mass binary stars: the fragmentation of a collapsing, initially elongated dense molecular core rotating end over end. This initial structure will develop into two independent gravitationally bound stellar condensations orbiting each other in a rather eccentric orbit.

scholarly journals The Calibration of Interferometrically Determined Properties of Binary Stars

1985 ◽  
Vol 111 ◽  
pp. 97-119
Author(s):  
Harold A. McAlister
Keyword(s):  
Binary Stars ◽  
Angular Resolution ◽  
Binary Star ◽  
Angular Separation ◽  
Speckle Interferometry ◽  
Close Binaries ◽  
High Angular Resolution ◽  
Fundamental Field ◽  
Enhanced Resolution ◽  
Stellar Masses

With the advent of speckle interferometry, high angular resolution has begun to play a routine role in the study of binary stars. Speckle and other interferometric techniques not only bring enhanced resolution to this classic and fundamental field but provide an equally important gain in observational accuracy. These methods also offer the potential for performing accurate differential photometry for binary stars of very small angular separation. This paper reviews the achievements of modern interferometric techniques in measuring stellar masses and luminosities and discusses the special calibration problems encountered in binary star interferometry. The future possibilities for very high angular resolution studies of close binaries are also described.

scholarly journals Binary Star Research: Where We Are Now and Future Prospects

1992 ◽  
Vol 151 ◽  
pp. 245-252
Author(s):  
E. F. Guinan
Keyword(s):  
Binary Stars ◽  
Binary Star ◽  
Close Binary ◽  
Future Prospects ◽  
Close Binary Stars

A review of IAU Symposium 151 on Interacting Binary Stars is given along with discussions of the present and future prospects of research in close binary stars.

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