MOCCA-SURVEY Database -- I. Tidal disruption events of white dwarfs in globular clusters and young massive clusters

We exploit more than 1000 star cluster Monte Carlo models from the MOCCA-SURVEY Database I, to infer the local rate density of white dwarf (WD) tidal disruption events (TDEs) in globular clusters (GCs) and young massive clusters (YMCs). We suggest that the WD TDE rate for GCs and YMCs in the local universe is $\sim 90$-$500~{\rm yr}^{-1}~{\rm Gpc}^{-3}$, with 90 % of WD TDEs occurring in GCs. The total WD TDE rate density is $\sim 9$-$50$ times larger than estimated before. Our results show that thermonuclear explosions induced by WD TDEs can be observed at a rate of $\sim 100$-$550~{\rm yr}^{-1}$ by the next generation optical surveys, such as the Legacy Survey of Space & Time by the Vera C. Rubin Observatory. We also find that massive WDs are preferentially disrupted due to mass segregation, and that 20 % of exploding WDs have $\gtrsim 1.0 M_\odot$ despite of the small population of such WDs.