View source for Astronomical object

{{Short description|Natural physical entity in space}}
{{About|naturally occurring objects|astronomical objects of the Solar System|List of Solar System objects|artificial objects|Satellite}}
{{Redirect2|Celestial object|Celestial body|the subtle body postulated in philosophy|Body of light|other uses|Celestial (disambiguation){{!}}Celestial}} 
{{Redirect2|Heavenly body|Heavenly bodies||Heavenly Body (disambiguation)|and|Heavenly Bodies (disambiguation)}}

{{Multiple image
|perrow=2/2/2/3/2/2/2/2
|total_width=325
|image1=243 ida.jpg{{!}}Asteroid Ida with its own moon
|link1=243 Ida
|image2=Mimas Cassini.jpg{{!}}Mimas, a natural satellite of Saturn
|link2=Mimas (moon)
|image3=Portrait of Jupiter from Cassini.jpg{{!}}Planet Jupiter, a gas giant
|link3=Jupiter
|image4=C2014 Q2.jpg
|link4=C/2014 Q2 (Lovejoy)
|image5=67P Churyumov-Gerasimenko - Rosetta (32755885495).png{{!}}Comet 67P/Churyumov–Gerasimenko
|link5=67P/Churyumov–Gerasimenko
|image6=Neptune Voyager2 color calibrated.png{{!}}Planet Neptune, an ice giant
|link6=Neptune
|image7=The_Sun_in_white_light.jpg{{!}}The Sun, a G-type star
|link7=Sun
|image8=Sirius A and B Hubble photo.editted.PNG{{!}}Star Sirius A with white dwarf companion Sirius B
|link8=Sirius#Visibility
|image9=Crab Nebula.jpg{{!}}The Crab Nebula, a supernova remnant
|link9=Crab Nebula
|image10=A_view_of_the_Milky_Way_supermassive_black_hole_Sagittarius_A*_in_polarised_light_(eso2406a).jpg{{!}}Sagittarius A*, a supermassive black hole
|link10=Sagittarius A*
|image11=Vela Pulsar jet.jpg{{!}}Vela pulsar, a rotating neutron star
|link11=Vela pulsar
|image12=A Swarm of Ancient Stars - GPN-2000-000930.jpg{{!}}Globular star cluster
|link12=Messier 80
|image13=Pleiades large.jpg{{!}}Pleiades, an open star cluster
|link13=Pleiades
|image14=Messier51 sRGB.jpg{{!}}The Whirlpool galaxy
|link14=Whirlpool galaxy
|image15=Heic1401a-Abell2744-20140107.jpg{{!}}Abel 2744, Galaxy cluster
|link15=Abell 2744
|image16=NASA-HS201427a-HubbleUltraDeepField2014-20140603.jpg{{!}}The Hubble Ultra-Deep Field 2014 image with an estimated 10,000 galaxies
|link16=Hubble Ultra-Deep Field
|image17=2MASS LSS chart-NEW Nasa.jpg{{!}}Map of galaxy superclusters and filaments
|footer=Selection of astronomical bodies and objects
|link17=Galaxy supercluster
}}

An '''astronomical object''', '''celestial object''', '''stellar object''' or '''heavenly body''' is a naturally occurring [[physical object|physical entity]], association, or structure that exists within the [[observable universe]].<ref>{{cite web |title=Naming Astronomical Objects |url=http://www.iau.org/public/naming/ |author=Task Group on Astronomical Designations from IAU Commission 5 |date=April 2008 |publisher=International Astronomical Union (IAU) |access-date=4 July 2010| archive-url= https://web.archive.org/web/20100802140541/http://www.iau.org/public/naming/#minorplanets| archive-date= 2 August 2010 | url-status= live}}</ref> In [[astronomy]], the terms ''object'' and ''body'' are often used interchangeably. However, an '''astronomical body''' or '''celestial body''' is a single, tightly bound, contiguous entity, while an astronomical or celestial ''object'' is a complex, less cohesively bound structure, which may consist of multiple bodies or even other objects with substructures.

Examples of astronomical objects include [[planetary system]]s, [[star cluster]]s, [[nebula]]e, and [[galaxy|galaxies]], while [[asteroid]]s, [[natural satellite|moons]], [[planet]]s, and [[star]]s are astronomical bodies. A [[comet]] may be identified as both a body and an object: It is a ''body'' when referring to the frozen [[Comet nucleus|nucleus]] of ice and dust, and an ''object'' when describing the entire comet with its diffuse [[Coma (cometary)|coma]] and [[Comet tail|tail]].

== History ==
{{Further|History of astronomy}}{{See also|Scientific Revolution|Copernican Revolution}}
Astronomical objects such as [[star]]s, [[planet]]s, [[nebula]]e, [[asteroid]]s and [[comet]]s have been observed for thousands of years, although early cultures thought of these bodies as [[deities]]. These early cultures found the movements of the bodies very important as they used these objects to help navigate over long distances, tell between the seasons, and to determine when to plant crops. During the [[Middle Ages]], cultures began to study the movements of these bodies more closely. Several astronomers of the Middle East began to make detailed descriptions of stars and nebulae, and would make more accurate calendars based on the movements of these stars and planets. In Europe, astronomers focused more on devices to help study the celestial objects and creating textbooks, guides, and [[universities]] to teach people more about astronomy.

During the [[Scientific Revolution]], in 1543, [[Nicolaus Copernicus|Nicolaus Copernicus's]] [[Heliocentrism|heliocentric model]] was published. This model described the [[Earth]], along with all of the other planets as being astronomical bodies which orbited the [[Sun]] located in the center of the [[Solar System]]. [[Johannes Kepler]] discovered [[Kepler's laws of planetary motion]], which are properties of the orbits that the astronomical bodies shared; this was used to improve the heliocentric model. In 1584, [[Giordano Bruno]] proposed that all distant stars are their own suns, being the first in centuries to suggest this idea. [[Galileo Galilei]] was one of the first astronomers to use telescopes to observe the sky, in 1610 he observed the four largest moons of [[Jupiter]], now named the [[Galilean moons]]. Galileo also made observations of the phases of [[Venus]], craters on the [[Moon]], and [[Sunspot|sunspots]] on the Sun. Astronomer [[Edmond Halley]] was able to successfully predict the return of [[Halley's Comet]], which now bears his name, in 1758. In 1781, [[Sir William Herschel]] discovered the new planet [[Uranus]], being the first discovered planet not visible by the naked eye. 

In the 19th and 20th centuries, new technologies and scientific innovations allowed scientists to greatly expand their understanding of astronomy and astronomical objects. Larger telescopes and observatories began to be built and scientists began to print images of the Moon and other celestial bodies on photographic plates. New [[wavelength]]s of light unseen by the human eye were discovered, and new telescopes were made that made it possible to see astronomical objects in other wavelengths of light. [[Joseph von Fraunhofer]] and [[Angelo Secchi]] pioneered the field of [[spectroscopy]], which allowed them to observe the composition of stars and nebulae, and many astronomers were able to determine the masses of binary stars based on their [[orbital elements]]. Computers began to be used to observe and study massive amounts of astronomical data on stars, and new technologies such as the [[Photoelectric effect|photoelectric]] [[photometer]] allowed astronomers to accurately measure the color and luminosity of stars, which allowed them to predict their temperature and mass. In 1913, the [[Hertzsprung–Russell diagram]] was developed by astronomers [[Ejnar Hertzsprung]] and [[Henry Norris Russell]] independently of each other, which plotted stars based on their luminosity and color and allowed astronomers to easily examine stars. It was found that stars commonly fell on a band of stars called the [[main-sequence]] stars on the diagram. A refined scheme for [[stellar classification]] was published in 1943 by [[William Wilson Morgan]] and [[Philip Childs Keenan]] based on the Hertzsprung–Russell diagram. Astronomers also began debating whether other galaxies existed beyond the [[Milky Way]], these debates ended when [[Edwin Hubble]] identified the [[Andromeda Galaxy|Andromeda nebula]] as a different galaxy, along with many others far from the Milky Way.

== Galaxy and larger ==
The [[universe]] can be viewed as having a hierarchical structure.<ref>{{cite book | first=Jayant V. | last=Narlikar | date=1996 | title=Elements of Cosmology | publisher=Universities Press | isbn=81-7371-043-0 | url=https://books.google.com/books?id=uZgbMUypq_oC&pg=PA4 }}</ref> At the largest scales, the fundamental component of assembly is the [[galaxy]]. Galaxies are organized into [[Galaxy groups and clusters|groups and clusters]], often within larger [[supercluster|superclusters]], that are strung along great [[galaxy filament|filaments]] between nearly empty [[Void (astronomy)|voids]], forming a web that spans the observable universe.<ref name=smolin1998>{{cite book | first=Lee | last=Smolin | date=1998 | page=[https://archive.org/details/lifecosmos00smol/page/n43 35] | title=The life of the cosmos | url=https://archive.org/details/lifecosmos00smol | url-access=limited | publisher=[[Oxford University Press US]] | isbn=0-19-512664-5 }}</ref>

Galaxies have a variety of [[Galaxy morphological classification|morphologies]], with [[irregular galaxy|irregular]], [[elliptical galaxy|elliptical]] and [[disc galaxy|disk-like]] shapes, depending on their formation and evolutionary histories, including [[interacting galaxy|interaction]] with other galaxies, which may lead to a [[galaxy merger|merger]].<ref>{{cite book |author1=Buta, Ronald James |author2=Corwin, Harold G. |author3=Odewahn, Stephen C. | page=301 | date=2007 | title=The de Vaucouleurs atlas of galaxies | publisher=[[Cambridge University Press]] | isbn=978-0-521-82048-6 }}</ref> Disc galaxies encompass [[lenticular galaxy|lenticular]] and [[spiral galaxy|spiral galaxies]] with features, such as [[Spiral galaxy#Spiral arms|spiral arms]] and a distinct [[Galactic halo|halo]]. At the core, most galaxies have a [[supermassive black hole]], which may result in an [[active galactic nucleus]]. Galaxies can also have satellites in the form of [[dwarf galaxy|dwarf galaxies]] and [[globular cluster]]s.<ref>{{Cite book |url=https://books.google.com/books?isbn=0521318874 |title=Astronomical Objects for Southern Telescopes |isbn=0521318874 |access-date=13 February 2017|last1=Hartung |first1=Ernst Johannes |date=1984-10-18 |publisher=CUP Archive }}</ref>

== Within a galaxy ==
The constituents of a galaxy are formed out of gaseous matter that assembles through gravitational self-attraction in a hierarchical manner. At this level, the resulting fundamental components are the stars, which are typically assembled in clusters from the various condensing nebulae.<ref>{{cite conference | last=Elmegreen | first=Bruce G. | title=The nature and nurture of star clusters | book-title=Star clusters: basic galactic building blocks throughout time and space, Proceedings of the International Astronomical Union, IAU Symposium | volume=266 | pages=3–13 |date=January 2010 | doi=10.1017/S1743921309990809 | bibcode=2010IAUS..266....3E |arxiv = 0910.4638 }}</ref> The great variety of stellar forms are determined almost entirely by the mass, composition and evolutionary state of these stars. Stars may be found in multi-star systems that orbit about each other in a hierarchical organization. A planetary system and various minor objects such as asteroids, comets and debris, can form in a hierarchical process of accretion from the [[protoplanetary disk]]s that surround newly formed stars.

The various distinctive types of stars are shown by the [[Hertzsprung–Russell diagram]] (H–R diagram)—a plot of absolute stellar luminosity versus surface temperature. Each star follows an [[evolutionary track]] across this diagram. If this track takes the star through a region containing an [[intrinsic variable]] type, then its physical properties can cause it to become a [[variable star]]. An example of this is the [[instability strip]], a region of the H-R diagram that includes [[Delta Scuti variable|Delta Scuti]], [[RR Lyrae variable|RR Lyrae]] and [[Cepheid variable]]s.<ref name=hansen_et_al2004>{{cite book
 | first=Carl J. | last=Hansen |author2=Kawaler, Steven D.|author3= Trimble, Virginia
 | page=[https://archive.org/details/springer_10.1007-978-1-4419-9110-2/page/n98 86] | title=Stellar interiors: physical principles, structure, and evolution
 | url=https://archive.org/details/springer_10.1007-978-1-4419-9110-2 | series=Astronomy and astrophysics library
 | edition=2nd | publisher=Springer | date=2004
 | isbn=0-387-20089-4 }}</ref> The evolving star may eject some portion of its atmosphere to form a nebula, either steadily to form a [[planetary nebula]] or in a [[supernova]] explosion that leaves a [[supernova remnant|remnant]]. Depending on the initial mass of the star and the presence or absence of a companion, a star may spend the last part of its life as a [[compact star|compact object]]; either a [[white dwarf]], [[neutron star]], or [[black hole]].

==Shape{{anchor|Shapes}}==
{{further|Spherical Earth#Cause}}
{{see also|Equatorial bulge|Hydrostatic equilibrium#Planetary geology}}

[[File:Eros, Vesta and Ceres size comparison.jpg|thumb|Composite image showing the round dwarf planet [[Ceres (dwarf planet)|Ceres]]; the slightly smaller, mostly round [[4 Vesta|Vesta]]; and the much smaller, much lumpier [[433 Eros|Eros]]]]

The [[IAU definition of planet|IAU definitions of planet]] and [[dwarf planet]] require that a Sun-orbiting astronomical body has undergone the rounding process to reach a roughly spherical shape, an achievement known as [[hydrostatic equilibrium]]. The same [[spheroidal]] shape can be seen on smaller rocky planets like [[Mars]] to [[gas giant]]s like [[Jupiter]].

Any natural Sun-orbiting body that has not reached hydrostatic equilibrium is classified by the IAU as a [[small Solar System body]] (SSSB). These come in many non-spherical shapes which are lumpy masses accreted haphazardly by in-falling dust and rock; not enough mass falls in to generate the heat needed to complete the rounding. Some SSSBs are just collections of relatively small rocks that are weakly held next to each other by gravity but are not actually fused into a single big [[bedrock]]. Some larger SSSBs are nearly round but have not reached hydrostatic equilibrium. The small Solar System body [[4 Vesta]] is large enough to have undergone at least partial planetary differentiation.

Stars like the Sun are also spheroidal due to gravity's effects on their [[plasma (physics)|plasma]], which is a free-flowing [[fluid]]. Ongoing [[stellar fusion]] is a much greater source of heat for stars compared to the initial heat released during their formation.

== Categories by location ==
{{See also|Lists of astronomical objects}}
{{See also|List of Solar System objects by size}}

The table below lists the general categories of bodies and objects by their location or structure.

{| class="wikitable" style="white-space: nowrap;"
|-
! rowspan=2 valign="middle"| Solar bodies
! colspan=3 | Extrasolar
! rowspan=2 valign="middle"| [[Observable universe]]
|-
! Simple bodies
! Compound objects
! Extended objects
|- valign="top"
|
<div style="background-color: #ccffcc; border-top: 1px solid #00CC00; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Solar System]]</div>
* [[Terrestrial planet]]
* [[Giant planet]]
** [[Gas giant]]
** [[Ice giant]]
* [[Heliosphere]]
* [[Oort cloud]]
** [[Hills Cloud]]
* [[Meteoroid]]
** [[Micrometeoroid]]
* [[Meteor]]
** [[Bolide]]
* [[Moons of the Solar System|Moons]]
** [[Moonlet]]s
** [[Subsatellite]]s {{small|(hypothet.)}}
* [[Minor planets]] {{small|(see below)}}
** [[Asteroid]]s
** [[Dwarf planet]]s
** [[Minor-planet moon|Moons]]
** [[Binary asteroid|Binaries]]
** [[Synestia]] {{small|(hypothet.)}}
* [[Planet]]s {{small|(see below)}}
** [[Ring system (astronomy)|Ring system]]
* [[Trans-Neptunian object]]s
* [[Small Solar System body]]
** [[Comet]]s
** [[Planetesimal]]
** [[Contact binary (small Solar System body)|Contact binary]]
* [[Sun]]

<div style="background-color: #ccffcc; border-top: 1px solid #00CC00; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Planets</div>
* [[Mercury (planet)|Mercury]]
* [[Venus]]
* [[Earth]] – [[Moon]]
* [[Mars]] – [[Moons of Mars|moons]]
* [[Jupiter]] – [[Moons of Jupiter|moons]]
* [[Saturn]] – [[Moons of Saturn|moons]]
* [[Uranus]] – [[Moons of Uranus|moons]]
* [[Neptune]] – [[Moons of Neptune|moons]]

<div style="background-color: #ccffcc; border-top: 1px solid #00CC00; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Dwarf planets</div>
* [[Pluto]] – [[Moons of Pluto|moons]]
* [[Eris (dwarf planet)|Eris]] – [[Dysnomia (moon)|Dysnomia]]
* [[Ceres (dwarf planet)|Ceres]]
* [[Makemake]] – [[S/2015 (136472) 1|moon]]
* [[Haumea]] – [[Moons of Haumea|moons]]
* [[Quaoar]] – [[Weywot (moon)|Weywot]]
* [[Orcus (dwarf planet)|Orcus]] – [[Vanth (moon)|Vanth]]
* [[Gonggong (dwarf planet)|Gonggong]] – [[Xiangliu (moon)|Xiangliu]]
* [[Sedna (dwarf planet)|Sedna]]
* [[List of possible dwarf planets|Others]]

<div style="background-color: #ccffcc; border-top: 1px solid #00CC00; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Minor planets</div>
* [[Vulcanoid]]s {{small|(hypothet.)}}
* [[ꞌAylóꞌchaxnim asteroid|ꞌAylóꞌchaxnims]]
* [[Atira asteroid|Atiras]]
* [[Near-Earth object]]s
** [[Potentially hazardous object|PHO]]
** [[Arjuna asteroid|Arjunas]]
** [[Aten asteroid|Atens]]
** [[Apollo asteroid|Apollos]]
** [[Amor asteroid|Amors]]
* [[Mars-crosser asteroid|Mars-crossers]]
* [[Asteroid belt]] {{small|([[Asteroid family|families]])}}
** [[Alinda family|Alindas]]
** [[Cybele asteroids|Cybeles]]
** [[Eos family|Eos]]
** [[Flora family|Floras]]
** [[Hilda asteroid|Hildas]]
** [[Hungaria family|Hungarias]]
** [[Hygiea family|Hygieas]]
** [[Koronis family|Koronis]]
** [[Maria family|Marias]]
** [[Nysa family|Nysas]]
** [[Pallas asteroid|Pallas]]
** [[Phocaea family|Phocaeas]]
** [[Themis family|Themis]]
** [[Vesta family|Vesta]]
* [[Trojan (astronomy)|Trojans]]
** [[Earth trojan|Earth]]
** [[Mars trojan|Mars]]
** [[Jupiter trojan|Jupiter]]
** [[Uranus trojan|Uranus]]
** [[Neptune trojan|Neptune]]
* [[Centaur (minor planet)|Centaurs]]
** [[Damocloid]]s
* [[Kuiper belt]] objects
** [[Classical Kuiper-belt object|Classical KBOs]]
** [[Resonant trans-Neptunian object|Resonant TNOs]]
*** [[Plutino]]s {{small|(2:3)}}
*** [[Twotino]]s {{small|(1:2)}}
* [[Scattered disc]] objects
** [[Detached object]]s
* [[Sednoid]]s

|
<div style="background-color: #FFCCCC; border-top: 1px solid #FF6666; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Exoplanet]]s</div>
* [[Chthonian planet|Chthonian]] {{small|(theoret.)}}
* [[Earth analog]]
* [[Eccentric Jupiter]]
* [[Exomoon]]
** [[Tidally detached exomoon]]
* [[Exocomet]]
* [[Hot Jupiter]]
* [[Hot Neptune]]
* [[Interstellar planet|Rogue planet]]
* [[Ocean planet|Ocean]] {{small|(theoret.)}}
* [[Pulsar planet]]
* [[Super-Earth]]
* [[Tidally locked|Tidally locked planet]]
** [[Eyeball planet]] {{small|(theoret.)}}
* [[Toroidal planet]] {{small|(theoret.)}}
* [[Trojan planet|Trojan]] {{small|(theoret.)}}
* [[Ultra-short period planet|USP]]

<div style="background-color: #FFD9B3; border-top: 1px solid #FF870F; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Brown dwarf]]s</div>
* Types
** [[Brown dwarf#Spectral class M|M]] {{·}} [[Brown dwarf#Spectral class L|L]] {{·}} [[Brown dwarf#Spectral class T|T]] {{·}} [[Brown dwarf#Spectral class Y|Y]]
* [[Sub-brown dwarf]]s

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Star]]s {{small|(see sections below)}}</div>
* [[Stellar classification]]
* [[Stellar population]] {{small|III, II, I}}
* [[Peculiar star]]
* [[Stellar evolution]]
* [[Variable star]]
* [[Compact star]]

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">By luminosity / [[Stellar evolution|evolution]]</div>
* [[Protostar]]
* [[Young stellar object]]
* [[Pre-main-sequence star|Pre-main-sequence]]
* [[Main sequence]]
* [[Subdwarf]]s
* [[Subgiant]]s
* [[Giant star|Giants]]
** [[Red giant|Red]] / [[Blue giant|Blue]]
* [[Bright giant]]s
* [[Supergiant]]s
** [[Red supergiant|Red]] / [[Blue supergiant|Blue]]
* [[Hypergiant]]s
* [[Ultra-cool dwarf]]
*[[Quasi-star]] {{Small|(hypothet.)}} 
* Compact stars {{small|(see below)}}

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Compact star]]s</div>
* [[Black hole]]
** [[Stellar black hole|Stellar]]
** [[Intermediate-mass black hole|Intermediate-mass]]
** [[Supermassive black hole|Supermassive]]
** [[Gamma ray burst|GRBs]]
** [[Binary black hole|BBHs]]
* [[Exotic star]] {{small|(hypothet.)}}
* [[Iron star]] {{small|(hypothet.)}}
* [[Neutron star]]
**[[Blitzar]] {{small|(hypothet.)}}
**[[Magnetar]]
** [[Pulsar]]
**[[Thorne–Żytkow object]] {{Small|(hypothet.)}}
* [[Planck star]] {{small|(hypothet.)}}
* [[Preon star]] {{small|(hypothet.)}}
* [[Quark star]] {{small|(hypothet.)}}
** [[Strange star]] {{small|(hypothet.)}}
* [[White dwarf]]
** [[Black dwarf]] {{small|(theoret.)}}

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">By [[peculiar star]]s</div>
* A-type
** [[Peculiar A-type star|Peculiar]] {{·}} [[Metallic A-type star|Metallic]]
* [[Barium star|Barium]]
* [[Blue straggler]]
* [[Carbon star|Carbon]]
* [[P Cygni star|P Cygni]]
* [[S-type star|S-type]]
* [[Shell star|Shell]]
* [[Wolf–Rayet star|Wolf–Rayet]]

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Variable star|Variables]] – [[Variable star#Extrinsic variable stars|Extrinsic]]</div>
* [[Rotating variable|Rotating]]
** [[Alpha2 Canum Venaticorum star|Alpha2 CVn]]
** [[Rotating ellipsoidal variable|Ellipsoidal]]
* [[Eclipsing binary|Eclipsing binaries]]
** [[Algol variable|Algol]]
** [[Beta Lyrae]]
** [[W Ursae Majoris]]

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Variable star|Variables]] – [[Variable star#Intrinsic variable stars|Intrinsic]]</div>
* [[Pulsating variable|Pulsating]]
** [[Cepheid variable|Cepheids]]
** [[W Virginis variable|W Virginis]]
** [[Delta Scuti variable|Delta Scuti]]
** [[RR Lyrae variable|RR Lyrae]]
** [[Mira variable|Mira]]
** [[Semiregular variable|Semiregular]]
** [[Irregular variable|Irregular]]
** [[Beta Cephei variable|Beta Cephei]]
** [[Alpha Cygni variable|Alpha Cygni]]
** [[RV Tauri variable|RV Tauri]]
* [[Eruptive variable]]s
** [[Flare star]]s
** [[T Tauri variable|T Tauri]]
** [[FU Orionis variable|FU Orionis]]
** [[R Coronae Borealis variable|RCr Borealis]]
** [[Luminous blue variable|Luminous blue]]
* [[Cataclysmic variable|Cataclysmic]]
** [[Symbiotic variable|Symbiotics]]
** [[Micronova]]
** [[Dwarf nova]]
** [[Nova]]
** [[Supernova]]
*** [[Supernova#Classification|Type:]] [[Type Ia supernova|Ia]] {{·}} [[Type Ib and Ic supernovae|Ib/c]] {{·}} [[Type II supernova|II]]
*** [[Hypernova]]
*** [[Gamma ray burst|GRBs]]
*** [[Failed supernova]]

<div style="background-color: #FFFF99; border-top: 1px solid #FFC966; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">By [[spectral type]]s</div>
* [[:Category:O-type stars|O]] {{small|(blue)}}
* [[:Category:B-type stars|B]] {{small|(blue-white)}}
* [[:Category:A-type stars|A]] {{small|(white)}}
* [[:Category:F-type stars|F]] {{small|(yellow-white)}}
* [[:Category:G-type stars|G]] {{small|(yellow)}}
* [[:Category:K-type stars|K]] {{small|(orange)}}
* [[:Category:M-type stars|M]] {{small|(red)}}

|
<div style="background-color: #D4E2FC; border-top: 1px solid #5F92F2; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Systems</div>
* [[Planetary system|Planetary]]
* [[Star system|Star]]
** [[Star|Stars in general]]
** [[Binary star|Binary]] {{small|(see below)}}
** [[Triple star system|Triples]]
** [[Star system#Higher multiplicities|Higher order]]

<div style="background-color: #D4E2FC; border-top: 1px solid #5F92F2; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Binary star]]s</div>
* By observation
** [[Optical binary|Optical]]
** [[Visual binary|Visual]]
** [[Astrometric binary|Astrometric]]
** [[Spectroscopic binary|Spectroscopic]]
** [[Eclipsing binary|Eclipsing]]
* Close binaries
** [[Detached binary|Detached]]
** [[Semidetached binary|Semidetached]]
** [[Contact binary|Contact]]
* [[X-ray binary|X-ray]]
** [[X-ray burster|Burster]]

<div style="background-color: #D4E2FC; border-top: 1px solid #5F92F2; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Stellar groupings</div>
* [[Star cluster]]
** [[Stellar association]]
** [[Open cluster|Open]]
** [[Globular cluster|Globular]]
** [[Hypercompact stellar system|Hypercompact]]
* [[Constellation]]
* [[Asterism (astronomy)|Asterism]]

<div style="background-color: #D4E2FC; border-top: 1px solid #5F92F2; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Galaxies</div>
* [[Galaxy|Galaxies in general]]
* [[Galaxy groups and clusters|Group and cluster]]
* [[Satellite galaxy]]
* [[Supercluster]]
* By component
** [[Galactic bulge|Bulge]]
** [[Spiral arm]]
** [[Thin disk]]
** [[Thick disk]]
** [[Galactic halo|Halo]]
** [[Galactic corona|Corona]]
** [[Tidal tail]]
** [[Stellar stream]]
* By [[Galaxy morphology|morphology]]
** [[Spiral galaxy|Spiral]]
** [[Barred spiral galaxy|Barred spiral]]
** [[Lenticular galaxy|Lenticular]]
** [[Elliptical galaxy|Elliptical]]
** [[Ring galaxy|Ring]]
** [[Irregular galaxy|Irregular]]
* By size
** [[Brightest cluster galaxy|Brightest cluster]]
** [[Giant elliptical galaxy|Giant elliptical]]
** [[Dwarf galaxy|Dwarf]]
* By type
** [[Protogalaxy]]
** [[Starburst galaxy|Starburst]]
** [[Dark galaxy (astronomy)|Dark]]
** [[Active galaxy|Active]]
*** [[Radio galaxy|Radio]]
*** [[Seyfert galaxy|Seyfert]]
*** [[Quasar]]
**** [[Microquasar]]
*** [[Blazar]]
**** [[OVV quasar|OVV]]
** [[Red nugget]]
** [[Void galaxy]]

|
<div style="background-color: #FFCCE6; border-top: 1px solid #FF339C; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">Discs and media</div>
* Interplanetary
** [[Interplanetary dust cloud|Dust cloud]]
** [[Interplanetary medium|Medium]]
** [[Interplanetary magnetic field|Magnetic field]]
* Stellar disc
** [[Accretion disc|Accretion]]
** [[Circumstellar disk|Circumstellar]]
*** [[Protoplanetary disk|Protoplanetary]]
*** [[Debris disk|Debris]]
* Interstellar
** [[Interstellar cloud|Cloud]]
** [[Interstellar medium|Medium]]
** [[Odd radio circle|ORCs]]
* Intergalactic
** [[Intergalactic dust|Dust]]
** [[Intergalactic medium|Medium]]
** [[Odd radio circle|ORCs]]
<div style="background-color: #FFCCE6; border-top: 1px solid #FF339C; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Nebula]]e</div>
* [[Emission nebula|Emission]]
** [[Planetary nebula|Planetary]]
** [[Supernova remnant]]
** [[Plerion]]
** [[H II region]]
* [[Reflection nebula|Reflection]]
* [[Dark nebula]]e
** [[Molecular cloud]]
** [[Bok globule]]
** [[Proplyd]]
* [[H I region]]
<div style="background-color: #FFCCE6; border-top: 1px solid #FF339C; font-size: bigger; padding-left: 15px; margin: 12px -5px -5px -5px;">[[Cosmology|Cosmic]] scale</div>
* [[Cosmic microwave background|CMB]]
* [[Cosmic string]] {{small|(hypothet.)}}
* [[Dark matter]]
** [[Massive compact halo object|MACHO]]
** [[Weakly interacting massive particles|WIMP]]
* [[Domain wall (string theory)|Domain wall]] {{small|(hypothet.)}}
* [[Cosmic dust|Dust]]
* [[Filament (cosmology)|Filament]]
* [[Large Quasar Group|LQG]]
* [[Void (astronomy)|Void]]
**[[Supervoid]]

|
{{multiple image
 |direction = vertical
 |align     = center
 |width     = 265
 |image1    = Observable_Universe_Logarithmic_Map_(vertical_layout_english_annotations)_for_wikipedia_635_x_2586.png
 |image2    = The Celestial Zoo infographic wikimedia.png
 |caption1  = Logarithmic representation of the observable<br />universe with the notable astronomical objects<br />known today. From down to up the celestial<br />bodies are arranged according to their proximity<br />to the Earth.
 |caption2  = Infographic listing 210 notable astronomical<br />objects marked on a central logarithmic map of<br />the observable universe. A small view and some<br />distinguishing features for each astronomical<br />object are included.
}}

|} <!-- end of table -->

== See also ==
{{Portal|Astronomy}}
* [[List of light sources]]
* [[List of Solar System objects]]
* [[List of Solar System objects by size]]
* [[Lists of astronomical objects]]
* [[Outer space]]

== References ==
{{reflist|30em}}

== External links ==
{{commons category|Astronomical objects}}
* {{webarchive |url=http://webarchive.loc.gov/all/20050613050209/http://skyandtelescope.com/observing/skychart/ |title= SkyChart, ''Sky & Telescope'' |date=2005-06-13}}
* [http://astroclub.tau.ac.il/skymaps/monthly/ Monthly skymaps for every location on Earth]. {{Webarchive|url=https://web.archive.org/web/20070913163917/http://astroclub.tau.ac.il/skymaps/monthly/ |date=2007-09-13 }}.
{{Portal bar|Astronomy|Stars|Spaceflight|Outer space|Solar System}}
{{Authority control}}

[[Category:Astronomical objects| ]]