What is "astynous"

Astynous or Astynoos is a name that may refer to one of the following characters in Greek mythology:

• Astynous, son of Phaethon (son of Eos).
• Astynous, a defender of Troy killed by Diomedes.
• Astynous (son of Protiaon), another defender of Troy, to whom Polydamas entrusted his horses before going into the battle; he was killed by Neoptolemus.