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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:1
UID:UW-Physics-Event-6605
DTSTART:20211116T200000Z
DTEND:20211116T210000Z
DTSTAMP:20260414T193122Z
LAST-MODIFIED:20211111T185906Z
LOCATION:https://berkeley.zoom.us/j/99464252867 Meeting ID: 994 6425 2
 867
SUMMARY:The fate of twin stars on the unstable branch\, Network in Neu
 trinos\, Nuclear Astrophysics\, and Symmetries (N3AS) Seminar\, Pedro 
 Espino\, University of California\, Berkeley and Pennsylvania State Un
 iversity
DESCRIPTION:Hybrid hadron-quark equations of state that give rise to a
  third family of stable compact stars have been shown to be compatible
  with the LIGO-Virgo event GW170817. Stable configurations in the thir
 d family are called hybrid hadron-quark stars. The equilibrium stable 
 hybrid hadron-quark star branch is separated by the stable neutron sta
 r branch with a branch of unstable hybrid hadron-quark stars. The end-
 state of these unstable configurations has not been studied\, yet\, an
 d it could have implications for the formation and existence of twin s
 tars — hybrid stars with the same mass as neutron stars but differen
 t radii. We modify existing hybrid hadron-quark equations of state wit
 h a first-order phase transition in order to guarantee a well-posed in
 itial value problem of the equations of general relativistic hydrodyna
 mics\, and study the dynamics of non-rotating or rotating unstable twi
 n stars via 3-dimensional simulations in full general relativity. We f
 ind that unstable twin stars naturally migrate toward the hadronic bra
 nch. Before settling into the hadronic regime\, these stars undergo (q
 uasi)radial oscillations on a dynamical timescale while the core bounc
 es between the two phases. Our study suggests that it may be difficult
  to form stable twin stars if the phase transition is sustained over a
  large jump in energy density\, and hence it may be more likely that a
 strophysical hybrid hadron-quark stars have masses above the twin star
  regime. We also study the minimum-mass instability for hybrid stars\,
  and find that these configurations do not explode\, unlike the minimu
 m-mass instability for neutron stars. Additionally\, our results sugge
 st that oscillations between the hadronic and quark phases could provi
 de gravitational wave signals associated with such phase transitions i
 n core-collapse supernovae and white dwarf-neutron star mergers.
\n 
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 nhttps://berkeley.zoom.us/j/99464252867
\n 
\nMeeting ID: 994 6425 286
 7
URL:https://www.physics.wisc.edu/events/?id=6605
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