Andromeda XIX

{{Short description|Satellite galaxy of the Andromeda galaxy}}

{{for|the star|19 Andromedae}}

{{Infobox galaxy

| name = Andromeda XIX

| image =

| epoch = J2000

| ra = {{RA|00|19|32.10}}{{cite web|work=NASA/IPAC Extragalactic Database|title=Results for ANDROMEDA XIX|url=http://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=Andromeda+XIX&extend=no&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES

| access-date=January 15, 2017}}

| dec = {{DEC|+35|02|37.1}}

| constellation name = Andromeda

| z = 0.003903

| half_light_radius_pc = 1700 pc

| dist_ly = {{cvt|812.8|kpc|kly|lk=on|order=flip}}

| h_radial_v=

| type = dG

| appmag_v = −10.1

| absmag_v = 14.5

| size_v =

| notes = Satellite of Andromeda Galaxy, extremely diffuse

| names = And XIX, LEDA 5056919

}}

Andromeda XIX is a satellite galaxy of the Andromeda Galaxy (M31), a member of the Local Group, like the Milky Way Galaxy.{{cite web|title=Chart (Local Galaxies)|url=http://www.uni.edu/morgans/astro/course/Notes/section3/localgroup.html|publisher=University of Northern Iowa|access-date=18 April 2012}} Andromeda XIX is considered "the most extended dwarf galaxy known in the Local Group",{{cite journal

|last=McConnachie|first=Alan W.

|author2=Huxor, Avon

|author3=Martin, Nicolas F.

|author4=Irwin, Mike J.

|author5=Chapman, Scott C.

|author6=Fahlman, Gregory

|author7=Ferguson, Annette M. N.

|author8=Ibata, Rodrigo A.

|author9=Lewis, Geraint F.

|author10=Richer, Harvey

|author11=Tanvir, Nial R.

|display-authors=8

|title=A Trio of New Local Group Galaxies with Extreme Properties|journal=The Astrophysical Journal|date=1 December 2008|volume=688|issue=2|pages=1009–1020|doi=10.1086/591313|access-date=18 April 2012|arxiv = 0806.3988 |bibcode = 2008ApJ...688.1009M |s2cid=16950090

| url=http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008ApJ...688.1009M&link_type=ARTICLE&db_key=AST&high= }} and has been shown to have a half-light radius of 1.7 kiloparsec (kpc). It was discovered by the Canada–France–Hawaii Telescope, and is thought to be a dwarf galaxy.

As with other dwarf galaxies, Andromeda XIX is not producing new stars: 90% of its star formation occurred over 9 billion years ago. However, compared to dwarf galaxies of similar mass Andromeda XIX is extremely diffuse, like Antlia II.{{cite journal | arxiv=2209.12912 | bibcode=2022MNRAS.517.4382C | doi=10.1093/mnras/stac2794 | title=A detailed star formation history for the extremely diffuse Andromeda XIX dwarf galaxy | year=2022 | last1=Collins | first1=Michelle L M. | last2=Williams | first2=Benjamin F. | last3=Tollerud | first3=Erik J. | last4=Balbinot | first4=Eduardo | last5=Gilbert | first5=Karoline M. | last6=Dolphin | first6=Andrew | journal=Monthly Notices of the Royal Astronomical Society | volume=517 | issue=3 | pages=4382–4388 | doi-access=free }}