Approximate Closed-Form Formulas for the Zeros of the Bessel Polynomials

We find approximate expressions and for the real and imaginary parts of the th zero of the Bessel polynomial . To obtain these closed-form formulas we use the fact that the points of well-defined curves in the complex plane are limit points of the zeros of the normalized Bessel polynomials. Thus, these zeros are first computed numerically through an implementation of the electrostatic interpretation formulas and then, a fit to the real and imaginary parts as functions of , and is obtained. It is shown that the resulting complex number is -convergent to for fixed .