Andromeda X

{{Short description|Galaxy in constellation Andromeda}}

{{distinguish|Chi Andromedae|10 Andromedae}}

{{Infobox Galaxy

| name = Andromeda X

| epoch = J2000

| type = dSph

| ra = {{RA|01|06|33.9}}

| dec = {{DEC|+44|48|16}}

| dist_ly =

| appmag_v = 16.1

| absmag_v = -8.1

| size_v = 7 arcmin

| constellation name = Andromeda

| notes = satellite galaxy of the Andromeda Galaxy

| names = And X, PGC 5056921

}}

Andromeda X (And 10) is a dwarf spheroidal galaxy about 2.9 million light-years away from the Sun in the constellation Andromeda.{{Cite web |title=Andromeda X |url=http://spider.seds.org/spider/LG/and10.html |access-date=2022-04-06 |website=spider.seds.org}} Discovered in 2005 by Zucker et al., And X is a satellite galaxy of the Andromeda Galaxy (M31). Aided by the application of stellar photometry to data from the Sloan Digital Sky Survey similar to the Andromeda IX discovery, the new finding indicates that this type of extremely faint satellite might be common in the Local Group, potentially providing further support for hierarchical cold dark matter models.{{Cite journal |last1=Zucker |first1=Daniel B. |last2=Kniazev |first2=Alexei Y. |last3=Martinez-Delgado |first3=David |last4=Bell |first4=Eric F. |last5=Rix |first5=Hans-Walter |last6=Grebel |first6=Eva K. |last7=Holtzman |first7=Jon A. |last8=Walterbos |first8=Rene A. M. |last9=Rockosi |first9=Constance M. |last10=York |first10=Donald G. |last11=Barentine |first11=J. C. |date=2006-01-26 |title=Andromeda X, A New Dwarf Spheroidal Satellite of M31: Photometry |journal=The Astrophysical Journal |volume=659 |pages=L21–L24 |language=en |doi=10.1086/516748|arxiv=astro-ph/0601599 |s2cid=1064929 }}