As of August 2019 , among the more than 4000 confirmed exoplanets , only one has been detected in a globular cluster ( GC ) M4 .
The scarce of exoplanet detections motivates us to employ direct N -body simulations to investigate the dynamical stability of planets in young massive clusters ( YMCs ) , which are potentially the progenitors of GCs .
In an N = 128 { k } cluster of virial radius 1.7 pc ( comparable to Westerlund-1 ) , our simulations show that most wide-orbit planets ( a \geq 20 au ) will be ejected within a timescale of 10 Myr .
Interestingly , more than 70 \% of planets with a < 5 au survive in the 100 Myr simulations .
Ignoring planet-planet scattering and tidal damping , the survivability at t Myr as a function of initial semi-major axis a _ { 0 } in au in such a YMC can be described as f _ { surv } ( a _ { 0 } ,t ) = -0.33 \log _ { 10 } ( a _ { 0 } ) \left ( 1 - e ^ { -0.0482 t } \right ) +1 .
Upon ejection , about 28.8 \% of free-floating planets ( FFPs ) have sufficient speeds to escape from the host cluster at a crossing timescale .
The other FFPs will remain bound to the cluster potential , but the subsequent dynamical evolution of the stellar system can result in the delayed ejection of FFPs from the host cluster .
Although a full investigation of planet population in GCs requires extending the simulations to multi-Gyr , our results suggest that wide-orbit planets and free-floating planets are unlikely to be found in GCs .