Young stars in the Galactic Centre: a potential intermediate-mass star origin     

L. M. Dray  A. R. King  M. B. Davies 《Monthly notices of the Royal Astronomical Society》2006,372(1):31-44

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Aligning spinning black holes and accretion discs     

A. R. King  S. H. Lubow  G. I. Ogilvie  J. E. Pringle 《Monthly notices of the Royal Astronomical Society》2005,363(1):49-56

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The population of black widow pulsars     

A. R. King  M. E. Beer  D. J. Rolfe  K. Schenker  J. M. Skipp 《Monthly notices of the Royal Astronomical Society》2005,358(4):1501-1504

We consider the population of black widow pulsars (BWPs). The large majority of these are members of globular clusters. For minimum companion masses  ≲0.1 M_⊙  , adiabatic evolution and consequent mass loss under gravitational radiation appear to provide a coherent explanation of all observable properties. We suggest that the group of BWPs with minimum companion masses  ≳0.1 M_⊙  are systems relaxing to equilibrium after a relatively recent capture event. We point out that all binary millisecond pulsars (MSPs) with orbital periods   P ≲ 10  h are BWPs (our line of sight allows us to see the eclipses in 10 out of 16 cases). This implies that recycled MSPs emit either in a wide fan beam or a pencil beam close to the spin plane. Simple evolutionary ideas favour a fan beam.  相似文献   

Type Ia supernovae and remnant neutron stars     

A. R. King  J. E. Pringle  D. T. Wickramasinghe 《Monthly notices of the Royal Astronomical Society》2001,320(3):L45-L48

On the basis of the current observational evidence, we put forward the case that the merger of two CO white dwarfs produces both a Type Ia supernova explosion and a stellar remnant, the latter in the form of a magnetar. The estimated occurrence rates raise the possibility that many, if not most, Type Ia supernovae might result from white dwarf mergers.  相似文献   

The short-period supersoft source in M31     

A. R. King  J. P. Osborne  K. Schenker 《Monthly notices of the Royal Astronomical Society》2002,329(2):L43-L46

We show that the recently discovered short period supersoft source in M31 is probably a progenitor of a magnetic cataclysmic variable (CV). The white dwarf spins asynchronously because of the current high accretion rate. However its fieldstrength is typical of an AM Herculis system, which is what it will ultimately become. We discuss the relevance of this system to CV evolution, and its relation to some particular CVs with special characteristics.  相似文献   

The ultraviolet line spectrum of the soft X-ray transient XTE J1118+480: a CNO-processed core exposed     

C. A. Haswell  R. I. Hynes  A. R. King  K. Schenker 《Monthly notices of the Royal Astronomical Society》2002,332(4):928-932

We compare ultraviolet (UV) spectra of the recent soft X-ray transients XTE J1118+480 and XTE J1859+226. The emission line strengths in XTE J1118+480 strongly suggest that the accreting material has been CNO processed. We show that this system must have come into contact with a secondary star of about 1.5 M_⊙, and an orbital period ∼15 h, very close to the bifurcation value at which the nuclear and angular momentum loss time-scales are similar. Subsequent evolution to the current period of 4.1 h was driven by angular momentum loss. In passing through a period of 7.75 h the secondary star would have shown essentially normal surface abundances. XTE J1118+480 could thus represent a slightly later evolutionary stage of A0620-00. We briefly discuss the broad Ly α absorption wings in XTE J1118+480.  相似文献   

Amplification of primordial magnetic fields by anisotropic gravitational collapse     

Emma J. King  Peter Coles 《Monthly notices of the Royal Astronomical Society》2006,365(4):1288-1294

If a magnetic field is frozen into a plasma that undergoes spherical compression, then the magnetic field B varies with the plasma density ρ according to   B ∝ρ^2/3  . In the gravitational collapse of cosmological density perturbations, however, quasi-spherical evolution is very unlikely. In anisotropic collapses the magnetic field can be a much steeper function of gas density than in the isotropic case. We investigate the distribution of amplifications in realistic gravitational collapses from Gaussian initial fluctuations using the Zel'dovich approximation. Representing our results using a relation of the form   B ∝ρ^α  , we show that the median value of α can be much larger than the value  α= 2/3  resulting from spherical collapse, even if there is no initial correlation between magnetic field and principal collapse directions. These analytic arguments go some way towards understanding the results of numerical simulations.  相似文献   

Minerals explained 40: The spinels     

R.J. King 《Geology Today》2004,20(5):194-200

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Contrast in life histories of exploited fishes and ecosystem structures in coastal waters off west Canada and east Korea     

Gordon A. McFarlane  Chang Ik Zhang  Jacquelynne R. King  Suam Kim  Richard J. Beamish  Jae Ho Oh 《Ocean Science Journal》2009,44(1):43-60

By reviewing the history of fishery exploitation in the coastal waters of west Canada and east Korea, related with contrasting life history strategies of the dominant species, the fishery management challenges that each country would face in the upcoming decades were outlined. In the ecosystem of the Canadian western coastal waters, the dominant oceanographic feature is the coastal upwelling domain off the west coast of Vancouver Island, the northernmost extent of the California Current System in the eastern North Pacific. In the marine ecosystem of the eastern coasts of Korea (the Japan/East Sea), a major oceanographic feature is the Tsushima Warm Current, a branch of the Kuroshio Current in the western North Pacific. Fishes in the Canadian ecosystem are dominated by demersal, long-lived species such as flatfish, rockfish, sablefish, and halibut. During summer, migratory pelagic species such as Pacific hake, Pacific salmon, and recently Pacific sardine, move into this area to feed. In the late 1970s, Canada declared jurisdiction for 200 miles from their coastline, and major fisheries species in Canadian waters have been managed with a quota system. The overall fishing intensity off the west coast of Vancouver Island has been relatively moderate compared to Korean waters. Fishes in the ecosystem of the eastern Korean waters are dominated by short-lived pelagic and demersal fish. Historically, Korea has shared marine resources in this area with neighbouring countries, but stock assessments and quotas have only recently (since the late-1990s) been implemented for some major species. In the Korean ecosystem, fisheries can be described as intensive, and many stocks have been rated as overfished. The two ecosystems responded differently to climate impacts such as regime shifts under different exploitation histories. In the future, both countries will face the challenge of global warming and subsequent impacts on ecosystems, necessitating developing adaptive fisheries management plans. The challenges will be contrasting for the two countries: Canada will need to conserve fish populations, while Korea will need to focus on rebuilding depleted fish populations.  相似文献   

Minerals explained 42     

R.J. King 《Geology Today》2005,21(4):153-157

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