Abstract
We derive the junction conditions for a general spherically symmetric radiating star with an electromagnetic field across a comoving surface. The interior consists of a charged composite field containing barotropic matter, a null dust and a null string fluid. The exterior atmosphere is described by the generalised Vaidya spacetime. We generate the boundary condition at the stellar surface showing that the pressure is determined by the interior heat flux, anisotropy, null density, charge distribution and the exterior null string density. A new physical feature that arises in our analysis is that the surface pressure depends on the internal charge distribution for generalised Vaidya spacetimes. It is only in the special case of charged Vaidya spacetimes that the matching interior charge distribution is equal to the exterior charge at the surface as measured by an external observer. Previous treatments, for neutral matter and charged matter, arise as special cases in our treatment of composite matter.
Highlights
The matching of general hypersurfaces was considered by Mars and Senovilla [29] and Fayos et al [30] in general relativity
We have modeled a radiating star with general spherical symmetry containing a composite matter distribution in the presence of an electromagnetic field across a comoving surface
To cater for various physical scenarios we have taken the stellar interior to contain a combination of a barotropic fluid, null dust and a null string fluid in the presence of an electromagnetic field
Summary
The matching of general hypersurfaces was considered by Mars and Senovilla [29] and Fayos et al [30] in general relativity. The matching of a composite matter distribution (a combination of a barotropic fluid, null dust and a null string) to the generalised Vaidya atmosphere was considered by Maharaj and Brassel [40]. We find that the interior general matter distribution, including the electromagnetic field, matches to an external generalised stellar atmosphere, i.e. the generalised Vaidya metric. This means that we can match a radiating stellar interior with a barotropic fluid, null dust, null string and an electric field, to an external stellar atmosphere described by the generalised Vaidya spacetime This feature should be incorporated in astrophysical models of radiating stars for a complete description of gravitating effects. M +, see the treatments of Santos [35], Herrera and Santos [45], Israel [49], O’Brien and Synge [50] and Lichnerowicz [51]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
