Below is a list of the largest known nebulae so far discovered, ordered by actual diameter. This list is prone to change because of inconsistencies between studies, the great distances of nebulae from our stellar neighborhood, and the constant refinement of technology and engineering.

Caveats Nebulae have no standardized boundaries, so the measurements are subject to revision. Furthermore, scientists are still defining the features and parameters of nebulae. Because of these rapid developments and adjustments, this list may be unreliable.

Lyman alpha nebulae around quasars can have sizes between 15 kpc and 460 kpc. Especially large Enormous Lyα nebula (ELAN) can have large sizes of ≳100 kpc. Farina et al. 2019 table 5 has an extensive compilation of Lyman alpha nebulae around quasars. For now this list contains only the largest ELANs, with sizes larger than 300 kpc.

List

+List of the largest nebulaeImage Nebula Maximum dimension(in light-years/parsecs) Type Notes Abell 3391/3395 ICM Intracluster medium (ICM) Continuous warm-hot emission filament between two galaxy clusters. Abell 1659S ICM Intracluster medium (ICM) One of the gas clumps of the Abell 1659 galaxy cluster. Abell 1659N ICM Intracluster medium (ICM) One of the gas clumps of the Abell 1659 galaxy cluster. Slug NebulaEnormous Lyα nebula (ELAN)Around the quasar UM287 at around z=2.3. Cosmic filament illuminated by the quasar.MAMMOTH-1Enormous Lyα nebula (ELAN)The nebula is associated with the galaxy overdensity BOSS1441, which is a protocluster at z=2.3. The nebula represents the circumgalactic medium. Its emission is powered by starburst and an obscured AGN. One of the most extended ELAN discovered as of 2019. NGC 262 Halo Cloud H I region Spiral nebula surrounding NGC 262, which is one of the largest known galaxies.Ivory NebulaEnormous Lyα nebula (ELAN)Also called MLAN1 at z=2.31. Another ELAN, called MLAN 10 is nearby.Q0042−2627 nebulaEnormous Lyα nebula (ELAN)Around the quasar LBQS 0042-2627, at z=3.280Jackpot NebulaEnormous Lyα nebula (ELAN)Four quasars embedded in the nebula. Likely progenitor of a massive galaxy cluster at z=2.05.Fabulous NebulaEnormous Lyα nebula (ELAN)Also called SDSS J1020+1040 nebula, after the central quasar (aka 4C 10.29), located at z=3.164. Inspiraling material. Will likely evolve into an elliptical galaxy. Leo Ring HVCA large ring of cold gas that formed from a collision of two galaxies. Magellanic Stream complex of HVCs Connects the Large and Small Magellanic clouds; extends across 180° of the sky.filament near TXS 0206-048[O II] nebulaLongest cool filament near a quasar as of 2022. Quasar is located at z=1.13. Filament is accreted into the galaxy and subsequently to the quasar.EELR of 3C 458emission line nebulaThe size is likely larger. The paper only describes the maximal distance to the nucleus and not the entire size.nebula around the Teacup galaxyionized nebulapart of the circumgalactic medium around the Teacup galaxy, illuminated by the AGNTON 618's lyman-alpha blob LαBSurrounds the quasar TON 618. Lyman-alpha blob 1 LαB Largest blob in the LAB Giant Concentration Himiko Gas Cloud Intergalactic cloud(possible LαB) One of the most massive lyman-alpha blobs known HVC 127-41-330 HVC Smith's Cloud HVC Extends about 20° of the sky Tarantula Nebula H II region Most active starburst region in the Local Group NGC 604 H II region Largest H II region located in the Triangulum Galaxy N44 Emission nebula Contains a 250 light year wide superbubble that was probably formed from stellar winds. N11H II region N11 is the second largest star formation region in the Large Magellanic Cloud galaxy.NGC 2404H II regionLargest H II region located in the spiral galaxy NGC 2403NGC 595H II region Contains massive stars that have strong stellar winds. Ring Nebula (NGC 6822)H II regionThe Ring Nebula is located in the lower right of the image Gum Nebula Emission nebula Extends about 36° of the sky Bubble Nebula (NGC 6822) H II region The Bubble Nebula is located in the upper left of the image NGC 6188 Emission nebulaNGC 592H II regionLocated in the Triangulum GalaxyCygnus X560 ly (170 pc)radio and infrared emission nebulaCygnus X is relative nearby, but hidden behind dark clouds, dimensions on the sky are 7° x 7° and distance is 1400 pc Sh2-310 H II region Nebula surrounding VY Canis Majoris, which is one of largest known stars. Carina Nebula H II region Nearest giant H II region to Earth Dragonfish Nebula Emission nebula N119430–570 ly (131–175 pc)H II regionPeculiar S-shape RCW 49 H II region Soul NebulaH II region Heart Nebula H II regionHas been named the “Heart nebula” because of its resemblance to a human heart. Henize 70 (N70 or DEM L301) H II region The N 70 Nebula, in the Large Magellanic Cloud has a shell structure and is really a bubble in space. It is a "Super Bubble". Barnard's Loop H II region Supernova over the last 4 million years probably carved cavities in gas clouds forming the semi circle shape of Barnard's loop. Sh2-54 H II region Prawn Nebula H II region Simeis 147 Supernova remnant NGC 7822 Emission nebula IC 2944 SEDS: IC 2944 Emission nebula Eagle Nebula H II region Part of another diffuse nebula IC 4703.Rosette NebulaH II regionOnly 36 stars were known to be in this nebula but the Chandra telescope increased the number of known stars to 160.Lagoon NebulaH II regionVeil NebulaSupernova remnantLocated in the Cygnus LoopNGC 3576Emission nebulaN41 Emission nebula The following well-known nebulae are listed for the purpose of comparison.Orion Nebula20 ly (6.132 pc)Diffuse NebulaThe closest major star formation region to Earth.Crab Nebula11 ly (3.4 pc)Supernova remnantThe remnant of a supernova that occurred in 1054 AD.Bubble Nebula6-10 ly (1.84-3.066 pc)Emission nebulaHelix Nebula5.74 ly (1.76 pc)Emission nebulaEightburst Nebula0.8 ly (0.2453 pc)Emission nebulaHomunculus Nebula0.58 ly (0.1778 pc) Emission nebulaSurrounds the star system Eta Carinae.Stingray Nebula0.16 ly (0.049 pc)Emission nebulaOne of the smallest nebulae.

See also List of largest cosmic structures List of largest known stars List of largest planets List of most massive stars List of most massive black holes List of largest galaxies

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References

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