\frac{R}{\lambda_P}\right)^2 M^2,$$ where in the second equation we neglected numerical constants of order 1, and took into account that typically $\omega R \simeq 10^{-1}$ or smaller. Taking then $\cE \simeq M \simeq N m$, $N$ of the order of the number of particles in an object of the size of the sun and density of liquid water, i.e., roughly $10^{56}$, $m \simeq 1 \,GeV$, the rotation period $T = 10^{-2} \,s$ and $R = 10^3\, km$ (comparable to the GW150914 parameters), and recalling that the Planck time $\tau_P \simeq 10^{-44}s$, we get that the fraction of energy radiated by the body per unit time is $$\frac{1}{\cE}\frac{d\cE}{dt} \simeq 10^{-89} s^{-1},$$ and it is therefore negligible.

To make this sizable $T$ ought rather to be of Planckian order, which would probably mean that our object collapsed into a black hole and no radiation is visible, and anyway the above Minkowskian picture does not apply.

This computation is certainly too primitive, but it suggests that the fraction of the total mass emitted as em radiation can be expected to be negligible; by far nothing comparable with the fraction of a few percents emitted as GW in the BBH collapse GW150914.

But could a 