Tidal Disruption of Blanets by Supermassive Black Holes: From Test Particles to Planetary-Mass Bodies in Kerr Spacetime

Blanets are planetary-mass bodies (20 -- 3000,) that may orbit supermassive black holes (SMBHs) in the circumnuclear disks of active galactic nuclei (AGN). We examine tidal disruption events produced by blanet--SMBH encounters, from the test-particle limit to massive planetary bodies in Kerr spacetime. Using the geodesic deviation equation and the Kerr tidal tensor, we derive disruption criteria, tidal radii, and Hills masses for planetary-mass objects, and show that blanet TDEs can remain observable for SMBHs up to about10 10,, well above the stellar Hills mass of about10 8,. The fallback rate retains the usual t-5/3 form, but the peak timescales are shorter -- from hours to months -- with lower peak accretion rates and multi-wavelength signatures that differ from those of stellar TDEs. We also examine orbital stability, including Keplerian precession, Lense--Thirring nodal precession, migration in the circumnuclear disk, and the Kozai--Lidov resonance, and identify the region where blanets can survive before disruption. We derive relativistic corrections to the tidal radius, spin-dependent disruption thresholds, and the effect of Kerr spin on the disruption geometry. We also discuss gravitational-wave emission from blanet debris EMRIs and the prospects for LISA detection, which may help in interpreting unusual TDE-like transients in AGN environments.