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SUMMARY:Dynamical Gravastars - Stephen Adler\, Princeton\, Institute for A
 dvanced Study
DTSTART:20240419T120000Z
DTEND:20240419T130000Z
UID:TALK213661@talks.cam.ac.uk
CONTACT:Xi Tong
DESCRIPTION:I give new results for  ``gravastars''\, which are horizonless
  compact objects that closely mimic mathematical black holes in their exte
 rior geometry\,  but for which $g_{00}$ is always positive.  In my initial
  formulation\, they result from  solving the  Tolman-Oppenheimer-Volkoff  
 (TOV) equations for relativistic stellar structure\, which require continu
 ous pressure\, but with an interior density jump from a normal matter equa
 tion of state\, to an equation of state where pressure plus density  appro
 ximately sum to zero.  We present  Mathematica notebooks solving the TOV e
 quations\, in which the structure of the gravastar is entirely governed by
  the Einstein-Hilbert gravitational action (with zero cosmological constan
 t) together with  the matter equation of state\, with  radii where structu
 ral changes occur  emerging from the dynamics\, rather than being specifie
 d in advance as in the original Mazur-Mottola gravastars. \n\nMy more rece
 nt work with a student shows  that the interesting ``simulated horizon'' s
 tructure of dynamical gravastars is a property solely of the exterior TOV 
 equations for relativistic matter with appropriate small radius boundary c
 onditions\, and will be present for a large class of interior equations of
  state.   The exterior TOV equations can be rewritten in rescaling-invaria
 nt form\, leading to a two dimensional autonomous system of differential e
 quations which are now being studied numerically and analytically \, and f
 or which hopefully some rigorous results can be proved.
LOCATION:Potter room/Zoom: https://cam-ac-uk.zoom.us/j/85670039340?pwd=MmR
 xMDdYMGY5b0IzSm9QRUJmWFNVUT09
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