I object to closing how to find the value of a? for "unclear what you are asking" because the question is obviously perfectly clear.
I think that definition creep is dangerous because once users see this behavior advocated, they'll start doing it themselves. To me an explicit close reason built into the SE interface should only be used for the purposes for which it is intended.
If the close reason you are thinking of isn't available, then maybe that's a suggestion that you should stop and think if the question really needs closing.
In this particular case I think there are already two SE tools available to address this question's lack of research, which does need some improvement.
Commenting: Advise and coach the OP why research is encouraged. In this case it's a new user's first question and SE allows new users to post without having to read "how to ask" so we coach and encourage them. In a relatively low question rate site like Space SE that usually works quite well.
Down voting: This is less desirable because most down voters don't revisit their down votes later to see if there is improvement. Nonetheless it is an option that is already available that doesn't require bending the rules.
Question: But doesn't voting to close as "unclear what you're asking" when the question is perfectly clear at least bend the rules by using a tool for which is clearly not intended? Isn't definition creep and user's getting the wrong idea that we can just use something something else problematic and counter to how SE works?