I mean this makes as much sense as demanding a formula that determines the difference between a mountain and a hill. And it is just as arbitrary so you haven't gained anything.
Well said.
"Tortoise" dealt with the general case thusly:
"Pretending that one can quantize a continuum rarely generates good results around the arbitrary boundary."
That pretty much says it all for this issue. Whether it is trying to draw a line that delineates modern humans from their more ancient ancestors, or planetoids from planets, or hills from mountains, they all fall into the trap of quantitzing the continuum. The boundaries are always arbitrary, and will almost always create debates regarding objects that are arbitrarily close to each other but which lie on opposing sides of the boundary we have arbitrarily imposed on the continuum to quantify it.