Signatures of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>−</mml:mo> </mml:msup> </mml:math> condensation on neutron star structure and <mml:math xmlns:mml="http://www.w3.org/1998/M

Antikaon ( K − ) condensation within neutron star matter (NS) depends on the antikaon-nucleon interaction potential ( U K ). Its onset softens the equation of state (EOS), and the resulting changes in stellar structure may serve as indicators of the phase transition from nucleonic matter to K − condensed matter. We investigate the impact of K − condensation on NS properties using Bayesian inference with two RMF parameter sets: the stiff DD2 and the softer FSU EOS. Multimessenger observations from NICER and LIGO/Virgo constrain U K = − 104 . 72 − 12.48 + 13.82 MeV (DD2) and U K = − 66 . 46 − 3.42 + 2.47 MeV (FSU) respectively. Deeper K − potentials trigger condensation at a lower density, softening the EOS and lowering the corresponding maximum masses. While slopes of mass-radius and tidal deformability curves overlap between nucleonic and exotic EOSs, their curvature and f − mode oscillation properties (frequency and damping time) reveal features attributable to EOS softening. However, distinguishing the specific exotic degrees of freedom responsible for the softening remains an open challenge.