Neutrino cloud
A neutrino cloud was an astronomical object composed of neutrinos that generated an electromagnetic field. They normally went undetected by 2370s Federation sensors.

The harmonic resonance of the neutrino clouds around Rosseau V occasionally became synchronous, causing sounds similar to music. ()

In 2376, Harry Kim gave a neutrino cloud as a possible cause for a graviton ellipse's changes in course. ()

Celestial objects