Young stellar object. (n.d.). In YourDictionary. Retrieved from https://www.yourdictionary.com/young-stellar-object
A protostar in which the dust and gas have collapsed into a sufficiently massive body for fusion to begin. The characteristic trait of young stellar objects is the presence of jet outflows—either of molecular gas or of radioactive emissions—that interact with the interstellar medium out of which the star has just been born.