Ultra-cool dwarf
[1] This category of dwarf stars was introduced in 1997 by J. Davy Kirkpatrick, Todd J. Henry, and Michael J. Irwin.As the age of the universe is only 13.8 billion years, all ultra-cool dwarf stars are therefore in the early portions of their life-cycles.Models predict that at the ends of their lives the smallest of these stars will become blue dwarfs rather than expanding into red giants.These observation campaigns identified the noteworthy 2MASS J10475385+2124234, which has a temperature of 800-900 K making it the coolest known radio-emitting brown dwarf (as of 2012).[7] More recent observations found an even colder ultracool dwarf with radio emission, called WISEPA J062309.94-045624.6 (T8),[8] with a temperature of around 740 K.[9]
TRAPPIST-1stellarsub-stellareffective temperaturedwarf starsJ. Davy KirkpatrickMichael J. Irwincoldest knownbrown dwarfsproto-planetary disksterrestrial planetsMercurysuper-Earthshydrogen fusionlow-mass starsage of the universeblue dwarfsred giantsArecibo ObservatoryVery Large Array2MASS J10475385+2124234brown dwarfmagnetic fieldEarth's magnetic fieldWISEPA J062309.94-045624.6BibcodePlanetDefinitionPlanetary scienceExoplanetExoplanet orbital and physical parametersMethods of detecting exoplanetsPlanetary systemPlanet-hosting starsTerrestrialCarbon planetCoreless planetDesert planetDwarf planetHycean planetIce planetIron planetLava planetOcean worldMega-EarthSub-EarthSuper-EarthGaseousEccentric JupiterMini-NeptuneHelium planetHot JupiterHot NeptuneGas giantIce giantSuper-JupiterSuper-NeptuneSuper-puffUltra-hot JupiterUltra-hot NeptuneBlanetChthonian planetCircumbinary planetCircumtriple planetDisrupted planetDouble planetEcumenopolisEyeball planetGiant planetMesoplanetPlanemoPlanetesimalProtoplanetPulsar planetSub-brown dwarfSub-NeptuneToroidal planetUltra-short period planet (USP)Formation and evolutionAccretionAccretion diskAsteroid beltCircumplanetary diskCircumstellar discCircumstellar envelopeCosmic dustDebris diskDetached objectExozodiacal dustExtraterrestrial materialsExtraterrestrial sample curationGiant-impact hypothesisGravitational collapseHills cloudInternal structureInterplanetary dust cloudInterplanetary mediumInterplanetary spaceInterstellar cloudInterstellar dustInterstellar mediumKuiper beltList of interstellar and circumstellar moleculesMolecular cloudNebular hypothesisOort cloudOuter spacePlanetary migrationProtoplanetary diskRing systemRubble pileSample-return missionScattered discStar formationSystemsExocometInterstellarExomoonTidally detachedRogue planetPulsarDetectionAstrometryMicrolensingPolarimetryRadial velocity