Strange-quark-matter Stars


Book Description

We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 13 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to consist of individual hadrons. We conclude that it is implausible that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, is a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation if strange matter is stable at an energy density exceeding about 5.4 times that of nuclear matter. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 34 refs., 10 figs., 1 tab.




Properties of Strange-matter Stars


Book Description

This paper deals with an investigation of the properties of hypothetical strange-matter stars, which are composed of u, d, s quark matter whose energy per baryon number lies below the one of 56Fe (Witten's strange matter hypothesis). Observable quantities which allow to distinguish such objects from their ''conventional'' counterparts, neutron stars and white dwarfs, are pointed out.




Strange-matter Stars


Book Description

This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts--neutron stars and white dwarfs--their properties are determined by two (rather than one) parameters, the central star density and the density at the base of the nuclear crust. This leads to stellar strange-matter configurations whose properties are much more complex than those of the conventional sequence. As an example, two generically different categories of stable strange dwarfs are found, which could be the observed white dwarfs. Furthermore the authors find very-low-mass strange stellar objects, with masses as small as those of Jupiter or even lighter planets. Such objects, if abundant enough, should be seen by the presently performed gravitational microlensing searches.




Compact Stars


Book Description

A whole decades research collated, organised and synthesised into one single book! Following a 60-page review of the seminal treatises of Misner, Thorne, Wheeler and Weinberg on general relativity, Glendenning goes on to explore the internal structure of compact stars, white dwarfs, neutron stars, hybrids, strange quark stars, both the counterparts of neutron stars as well as of dwarfs. This is a self-contained treatment and will be of interest to graduate students in physics and astrophysics as well as others entering the field.




Strange Stars, Strange Dwarfs, and Planetary-like Strange-matter Objects


Book Description

This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts--neutron stars and white dwarfs--their properties are determined by two (rather than one) parameters, the central star density and the density at the base of the nuclear crust. This leads to stellar strange-matter configurations whose properties are much more complex than those of the conventional sequence. As an example, two generically different categories of stable strange dwarfs are found, which could be the observed white dwarfs. Furthermore the authors find very-low-mass strange stellar objects, with masses as small as those of Jupiter or even lighter planets. Such objects, if abundant enough, should be seen by the presently performed gravitational microlensing searches.




Neutron Stars 1


Book Description

The book gives an extended review of theoretical and observational aspects of neutron star physics. With masses comparable to that of the Sun and radii of about ten kilometres, neutron stars are the densest stars in the Universe. This book describes all layers of neutron stars, from the surface to the core, with the emphasis on their structure and equation of state. Theories of dense matter are reviewed, and used to construct neutron star models. Hypothetical strange quark stars and possible exotic phases in neutron star cores are also discussed. Also covered are the effects of strong magnetic fields in neutron star envelopes.




Strange Matters:


Book Description

Scientists studying the universe find strange things in two placesâ€"out in space and in their heads. This is the story of how the most imaginative physicists of our time perceive strange features of the universe in advance of the actual discoveries. It is almost a given that physics and cosmology present us with some of the grandest mysteries of all. What weightier questions to ponder than, "How does the universe work?" or "What is the universe made of?" There are any number of bizarre phenomena that could provide clues or even answers to these queries. The strangeness ranges from unusual forms of matter and realms of existence to wild ideas about how time and space are related to one another. Many of these proposals may well turn out to be wrong. But how many will be proven to be right? This book speaks for the scientific theorists who are bold enough to imagine and predict the impossible. New ideas are percolating in their heads every day. One physicist may dream of subatomic particles that could resolve a variety of cosmological conundrums while another may study the likes of "funny energy," which may explain how rapidly the universe is expanding. This is the stuff of Strange Matters. In broad terms, this book is about a variety of discoveries that theorists of the past imagined before the observers and experimenters actually saw them. Moreover, it is about the things that today’s are now imaginingâ€"but haven't yet been discovered or confirmed by the observers. Strange Matters artfully mixes the present with the past and future, reporting from the frontiers of research where history is in the process of being made. Each chapter examines a different step along the twisted path we've walked to gain our rudimentary understanding of the universe, incorporating historical examples of successful "prediscoveries" with current stories that relate brand new ideas. We come to see the universe not only in terms of what has already been discovered, but also in terms of what has yet to be observed. Strange Matters is a guide to the discoveries of the twenty-first century, a series of visions dreamt by the most imaginative scientists of our time merged with the achievements of the pastâ€"to point the way towards even greater accomplishments of the future.







Compact Stars


Book Description

White dwarfs, neutron stars, and (solar mass) black holes are the collapsed cores of stars which, near the ends of their luminous lives, have shed most of their mass in supernova explosions or other, less spectacular, instabilities. Here gravity crushes matter to realms that lie far beyond present empirical knowledge. This book explores the diverse forms that such compact stars can possibly take, as constrained by the laws of nature: the general principles of relativity and quantum mechanics, the properties of nuclear matter deduced from nuclei, and the asymptotic freedom of quarks at high density. The book is self contained. It reviews general relativity, essential aspects of nuclear and particle physics, and general features of white dwarfs, neutron stars and black holes; it includes background on such matters as stellar formation and evolution, the discovery of pulsars and associated phenomena, and the strange-matter hypothesis. The book develops a theory for the constitution of neutron stars and the more exotic Hyperon Stars, Hybrid Stars (containing a quark matter core surrounded by an intricate lattice of quark and hadronic matter) and Strange Stars and Dwarfs (composed of the three light quark flavors sheathed in a solid skin of heavy ions). This second edition has been revised throughout to clarify discussions and bring data up to date; it includes new figures, several new sections, and new chapters on Bose condensates in neutron stars and on phase transitions.




Fast Pulsars, Compact Stars, and the Strange Matter Hypothesis


Book Description

Part one of this paper deals with the recent finding of the possible existence of a mixed phase of baryon matter and quark matter inside neutron stars. In part two we review the theoretically determined minimum rotational periods of neutron stars, which serve to distinguish between pulsars that can be understood as rotating neutron stars and those that can not. Likely candidates for the latter are hypothetical strange stars. Their mass-radius relationship is discussed in the last part. It is pointed out that strange stars with a nuclear crust can give rise to the observed phenomena of pulsar glitches, thus passing the only astrophysical test of the strange-matter hypothesis existing to date.