The asteroid 2063 Bacchus because IIRC Bacchus (Dionysus)'s tales have some themes of gender non-conformity. But in a more serious tone, the Hellenistic mythologies used to have some gender non-binary figures such as the statues of Aphroditus, but the Latin-speaking Italian Romans generally took gender roles very seriously even before Christianisation, so you'll probably have to find some non-Latin astronomical object.
As the planets were named after Roman deities created specifically to shoehorn celestial objects into binary gender roles, I don’t think the Roman pantheon would be a good model for non-binary identities.
And then they had to go a step further reduce gender roles into being represented by just those two gods. It’s like we’re going backwards.
Alpha Centauri maybe?
Thought to be a single star by the Greeks, but are a collection of many different stars in reality.