DDO 169

{{Infobox Galaxy

| name = DDO 169

| image = File:UGC 8331 color cutout hst 10905 18 acs wfc f814w f606w sci.jpg

| caption = DDO 169

| epoch = J2000

| constellation name = Canes Venatici

| ra = {{RA|13|15|30.31}}

| dec = {{DEC|+47|29|56.2}}

| z = +260 km/s

| dist_ly = 6.03 / 8.23 Mpc{{cite web|url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=UGC+8331&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| title =NED results for UGC 8331| publisher=NED via University of California| access-date=2009-03-08}}{{cite web|url=http://aas.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aas/pdf/1998/13/ds7328.pdf |title=Distances to five resolved galaxies in the Canes Venatici cloud |author1=I.D. Karachentsev |author2=I.O. Drovdozsky |date=July 1998 |publisher=Astronomy and Astrophysics Supplement Series |access-date=2009-03-08 }}{{dead link|date=December 2016 |bot=InternetArchiveBot |fix-attempted=yes }}
(19.7 / 26.8 million ly)

| type = IAm

| appmag_v = 14.61

| size_v = 2.7′ × 0.9'

| notes =

| names = UGC 8331, PGC 46127

}}

DDO 169 (also known as UGC 8331) is an irregular galaxy located in the constellation Canes Venatici. It is a member of the M51 Group of galaxies and measures approximately 5 × 1.5 kiloparsecs (16,000 × 5,000 lightyears). The galaxy's large-scale structure is very unorganized and it has two clusters of stars in its outer portions in addition to the cluster in the center.{{cite journal|arxiv=0901.4222| title=The rotation curves shapes of late-type dwarf galaxies|author1=R.A. Swaters |author2=R. Sancisi |author3=T.S. van Albada |author4=J.M. van der Hulst | date=2009-01-27| journal=Astronomy and Astrophysics|doi = 10.1051/0004-6361:200810516 |bibcode = 2009A&A...493..871S| volume=493| issue=3| pages=871–892| s2cid=14143255}} These clusters make it practically impossible to determine the galaxy's rotation curve and contributes to a large variation in distance figures that are derived with different methods. The exact distance to the galaxy is not known, although a 1998 paper estimated the distance as 8.23 megaparsecs.

References