substellar
Not quite stellar
Substellar describes celestial objects too small to sustain hydrogen fusion—the process that powers true stars.
Brown dwarfs are the most common substellar objects, sometimes called "failed stars" because they lack sufficient mass to ignite: The telescope detected a substellar companion orbiting the nearby red dwarf.
The term also applies to giant planets and other bodies below the stellar mass threshold.
Substellar object, no fusion
- deuteriumHydrogen isotope with neutron
- methaneSimplest alkane fuel
- infraredHeat-bearing electromagnetic waves
- hydrogen fusionAtoms merging, releasing energy
gas giant · companion · binary · luminosity · protostar · accretion · opacity · convective
Not fixed to anything
- rogue planetUnbound interstellar planet
- orbitalRevolving around another
- detectionAct of finding something
- transitMovement between places
formation · disk · protoplanetary · coronagraph · spectroscopy · atmosphere
After twelve, before fourteen
- seventy-fiveNumber after seventy-four
- classificationSystematic grouping by traits
- intermediateBetween two levels
- borderlineEdge of acceptability
definition · ignition · core temperature · fragmentation · nomenclature
brown dwarf
Substellar object, no fusion
- deuteriumHydrogen isotope with neutron
- methaneSimplest alkane fuel
- infraredHeat-bearing electromagnetic waves
hydrogen fusion · gas giant · companion · binary · luminosity · protostar · accretion · opacity · convective · degenerate
free-floating
Not fixed to anything
- rogue planetUnbound interstellar planet
- orbitalRevolving around another
- detectionAct of finding something
transit · formation · disk · protoplanetary · coronagraph · spectroscopy · atmosphere
thirteen
After twelve, before fourteen
- seventy-fiveNumber after seventy-four
- classificationSystematic grouping by traits
- intermediateBetween two levels
borderline · definition · ignition · core temperature · fragmentation · nomenclature
substellarstellar
Of or like celestial bodies
star · supermassive · massive star · supergiant · blue giant
substellarluminous
Emitting or reflecting light
self-luminous · radiant · blazing · incandescent · brilliant