Unbarred spiral galaxy

An unbarred spiral galaxy^[1]^[2] is a type of spiral galaxy without a central bar, or one that is not a barred spiral galaxy. It is designated with an SA in the galaxy morphological classification scheme. A nearby example of an unbarred spiral is the Triangulum Galaxy.

Barless spiral galaxies are one of three general types of spiral galaxies under the de Vaucouleurs system classification system, the other two being intermediate spiral galaxy and barred spiral galaxy. Under the Hubble tuning fork, it is one of two general types of spiral galaxy, the other being barred spirals.

Grades

Example	Type	Information	Notes
	SA0-	SA0- is a type of lenticular galaxy
	SA0	SA0 is a type of lenticular galaxy
	SA0+	SA0+ is a type of lenticular galaxy
NGC 3593	SA0/a	SA0/a can also be considered a type of unbarred lenticular galaxy	NGC 3593 is an "SA(s)0/a"
NGC 3169	SAa		NGC 3169 is an "SA(s)a pec"
Messier 81	SAab		M81 is an "SA(s)ab"
Messier 88	SAb		M88 is an "SA(rs)b"
NGC 3949	SAbc		NGC 3949 is an "SA(s)bc"
NGC 4414	SAc		NGC 4414 is an "SA(rs)c"
Triangulum Galaxy	SAcd		Triangulum is an "SA(s)cd"
NGC 300	SAd		NGC 300 is an "SA(s)d"
NGC 45	SAdm	SAdm can also be considered a type of unbarred Magellanic spiral	NGC 45 is an "SA(s)dm"
NGC 4395	SAm	SAm is a type of Magellanic spiral (Sm)	NGC 4395 is an "SA(s)m"

Unbarred lenticular galaxy

An unbarred lenticular galaxy is a lenticular version of an unbarred spiral galaxy. They have the Hubble type of SA0.

An example of this is the galaxy AM 0644-741. For other examples, see Category:Unbarred lenticular galaxies.

References

^ Astronomical Journal, "Near-infrared surface photometry and morphology in virgo cluster spiral galaxy nuclear regions", Bernard J. Rauscher, April 1995, Bibcode:1995AJ....109.1608R, doi:10.1086/117389
^ Astronomy Pictures, "M99" (accessed 18 April 2010)

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[1] Astronomical Journal, "Near-infrared surface photometry and morphology in virgo cluster spiral galaxy nuclear regions", Bernard J. Rauscher, April 1995, Bibcode:1995AJ....109.1608R, doi:10.1086/117389

[2] Astronomy Pictures, "M99" (accessed 18 April 2010)

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Morphology	Disc Lenticular barred unbarred Spiral anemic barred flocculent grand design intermediate Magellanic unbarred Dwarf galaxy elliptical irregular spheroidal spiral Elliptical galaxy cD Irregular barred Peculiar Ring Polar
Structure	Active galactic nucleus Bar Bulge Central massive object Galactic Center Dark matter halo Disc Disc galaxy Halo corona Galactic plane Galactic ridge Interstellar medium Protogalaxy Galaxy filament Spiral arm Supermassive black hole Ultramassive
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