I determined a parameter for an experiment – shall I ask for authorship?

Whether or not you should be an author on the paper is not about whether you did something, but whether you contributed intellectually. For example, a lab technician who washed the petri dishes and while everyone was working on the experiment in the background turned the dial of the radio to the station that everyone wanted to listened to (i.e., determined one parameter that was crucial to the experiment), did contribute to the experiment. But it was not an intellectual contribution, and so authorship is probably not warranted.

Without more details in your question, it is hard to tell whether you should or should not be an author on the paper. But, this is worth a conversation with your adviser. It's likely going to be a slightly awkward conversation, but it is one in which you can talk about the norms in your field, what qualifies as an "intellectual contribution" and why or why not everyone on the paper should or should not be an author.