Você está se referindo ao TNG " Half a Life ".
""Half a Life" is the 96th episode of the science fiction television series Star Trek: The Next Generation and the 22nd episode of the fourth season.
Lwaxana Troi falls in love with Timicin, a scientist who is participating in an experiment to test his theories of stellar ignition. Timicin hopes to use the technique to save his world's dying star, but the experiment fails. Although Lwaxana encourages Timicin to continue his research, the scientist reveals that he can't. It's time for him to go home for "Resolution"- a ritual suicide invoked at the age of sixty to save children from the burden of a parent's aging."