Can someone help me come up with a celestial body?

[Maximum7]

I decided that I’m going to have my scientist study an astrological body BUT it’s something that we haven’t identified in the real world. I’m no good at physics so I don’t know what kind of new astrological body I can make up. Does anybody have ideas for a fictional celestial body? Like something in the class of a quasar or a pulsar or a black hole

[tkulogo]

I'm not sure what you mean by "astrological" body, but if, by that, you mean "celestial" body, there's a number of theorized but never found objects. https://en.wikipedia.org/wiki/Hypothetical_star is a good list of hypothetical stars. The quasi-star is a personal favorite of mine. That's just stars, but smaller objects or also an option. I like grandmoons (https://en.wikipedia.org/wiki/Subsatellite), because they most likely exist but haven't been discovered.