Try to make sense of what you see below.
What's it called?
The answer to this puzzle is:
What?! Stiv, did you just mash the keyboard?!
Nope, allow me to explain... First, the significance of the five images:
1. The position on a clock of 55 minutes past the hour.
2. If you rotate the number '69' by a quarter turn it resembles the astrological symbol for CANCER (♋︎).
3. This is a picture of an Emergency Room, or ER. Because it is crossed out in the image, we need to remove the string 'ER' from 'CANCER' to produce CANC.
4. The outline of the US state of Rhode Island, abbreviated to RI.
5. A picture of Leonhard Euler, whose eponymous number is the mathematical constant 'e'.
Put these all together and you have 55 + CANC(-er) + RI + e, or 55 Cancri e.
But what does this even mean?! Well, this is actually:
the name of an exoplanet (hence the title's use of X-O-P as a hint). In fact, it is a very significant one, as when it was first identified in August 2004 it was the very first 'super-Earth' (i.e. a planet larger than our own, found in another solar system) discovered around a 'main sequence' star.
Whether or not the name is 'pretty cool' (or something Elon Musk might call his next child) is for you to decide!