Is a rock that usually stays in space, quite different to a meteor or shooting star.
To dream of it might suggest that some part of you is suspended and unable to act. But your associations with would need to explored as this is unusual to find in dreams. So see Acting on your dream.
Useful Questions and Hints:
What is happening to the asteroid in your dream? See Processing Dreams to clarify this.
Do you feel threatened by the asteroid? If so see Facing Fear.
Is it something uplifting?
Try using Talking As.