Stellam

Stellam is a fictional term used in speculative cosmology and science fiction to denote a class of circumstellar structures surrounding young stars. In common renderings, a stellam is a luminous, magnetically sculpted shell or torus composed of gas and dust that forms during or shortly after the protostellar phase. The structure typically spans tens to a few hundred astronomical units and can persist for millions of years within the narrative universe.

Observationally, stellams are described as emitting strongly in the infrared, with spectral features from silicates and carbon-based compounds, and showing polarization patterns consistent with ordered magnetic fields. In-universe formation scenarios include remnants of protoplanetary disks shaped by anisotropic winds, magnetically confined stellar outflows, or late-stage mass ejections from rapidly rotating protostars. The diversity of models reflects the fictional nature of the concept, with authors using stellams to explore disk evolution, planet formation, and star–disk interactions.

The term was introduced in the Starline Encyclopedia and has since appeared in multiple science fiction settings, sometimes with differing parameters or histories, but generally as a diagnostic feature indicating a complex circumstellar environment. In technical guides within those universes, stellams serve as a convenient shorthand for discussing grain growth, radiative transfer in dusty shells, and the potential habitability implications for orbiting bodies.

See also: circumstellar disk, protoplanetary disk, planetary nebula, magnetohydrodynamics.