8. A line $l$ is drawn through the right focus of the hyperbola $x^{2}-\frac{y^{2}}{2}=1$ intersecting the hyperbola at points $A$ and $B$. If a real number $\lambda$ makes $|A B|=\lambda$ such that there are exactly 3 such lines $l$, then $\lambda=$ $\qquad$.
By the symmetry of the hyperbola, when $|A B|=\lambda$ of the line $l$ is exactly 3, $\lambda=\max \left\{2 a, \frac{2 b^{2}}{a}\right\}$ $=\max \{2,4\}=4$, where $\frac{2 b^{2}}{a}$ is the length of the latus rectum of the hyperbola.