Fornax Dwarf: Difference between revisions

Revision as of 13:43, 12 October 2006

Latest revision as of 08:36, 18 June 2025

(105 intermediate revisions by 74 users not shown)

Line 1:

{{Short description|Dwarf galaxy in the constellation Fornax}}

{{Infobox Galaxy |

| image = ''No image.''

| nameimage = ''Fornax Dwarf''dwarf galaxy.jpg

| typeimage_size = dE2260px

| caption = The Fornax dwarf galaxy

| epoch = J2000.0

| name = ''Fornax Dwarf Spheroidal''

| ra = 2^h 39.9^m

| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]

| dec = −34° 32′

| type = dE0<ref name="ned">{{cite web

| dist_ly = [[1 E22 m|500,000]] [[light year|ly]]

| title=NASA/IPAC Extragalactic Database

| appmag_v = +9.3

| work=Results for Fornax Dwarf Spheroidal

| size_v = 17.0 &times; 12.6 [[Minute of arc|arcmins]]

| url=http://nedwww.ipac.caltech.edu/

| radius_ly = Unknown

| access-date=2006-11-29 }}</ref>

| absmag_v = &minus;13.5

| ra = {{RA|02|39|59.3}}<ref name="ned" />

| dec = {{DEC|-34|26|57}}<ref name="ned" />

| dist_ly = [[1 E21 m|466 ± 10]] [[light-year|kly]] (143 ± 3 [[parsec|kpc]])<ref name=Oakes>{{cite journal|doi=10.3847/1538-4357/ac5b07|title=Distances to Local Group Galaxies via Population II, Stellar Distance Indicators. II. The Fornax Dwarf Spheroidal |year=2022 |last1=Oakes |first1=Elias K. |last2=Hoyt |first2=Taylor J. |last3=Freedman |first3=Wendy L. |last4=Madore |first4=Barry F. |last5=Tran |first5=Quang H. |last6=Cerny |first6=William |last7=Beaton |first7=Rachael L. |last8=Seibert |first8=Mark |journal=The Astrophysical Journal |volume=929 |issue=2 |page=116 |arxiv=2204.09699 |bibcode=2022ApJ...929..116O |s2cid=248260222 |doi-access=free }}</ref>

| z = 53 ± 9 km/[[second|s]]<ref name="ned" />

| appmag_v = +9.3<ref name="ned" />

| size_v = 17.0{{prime}} × 12.6{{prime}}<ref name="ned" />

| constellation name = [[Fornax]]

| notes = has 6 globular clusters''

| names = E356-G04, PCGFornax 10093dSph,<ref A0237name="simbad">{{cite }}simbad

| title=NAME Fornax Dwarf Spheroidal

| access-date=2006-11-29}}</ref> Fornax Dwarf Elliptical,<ref name="simbad" /> Fornax Dwarf Galaxy,<ref name="simbad" /> Fornax dE,<ref name="simbad" /> [[Principal Galaxies Catalogue|PGC]] 10074 / 10093,<ref name="ned" /> ESO 356-4

|size=2.85 [[parsec|kpc]] / 9295 [[light year|ly]]<ref name="ned"/>}}

The '''Fornax Dwarf Spheroidal''' (formerly known as the '''Fornax System''') is a elliptical [[dwarf elliptical galaxy]] in the [[constellation]] [[Fornax]] that was discovered in 1938 by [[Harlow Shapley]]. He discovered it while he was in [[South Africa]] on photographic plates taken by athe 24 &nbsp;inch [[reflecting(61&nbsp;cm) telescope]]Bruce refractor at [[Boyden Observatory]], shortly after he discovered the [[Sculptor Dwarf Galaxy]].<ref>{{cite galaxyjournal | author = Shapley H | date = 1938 | title = Two Stellar Systems of a New Kind | journal = Nature | volume = 142 | issue = 3598| pages = 715–6 | bibcode = 1938Natur.142..715S | doi=10.1038/142715b0| s2cid = 4071472 }}</ref>

The [[galaxy]] is a satellite of the [[Milky Way]] and contains six [[globular clusterscluster]]s, an unusually high number for its size;<ref name=Pace/> the largest, [[NGC 1049]], was discovered before the galaxy itself. The galaxy is also receding from the [[Milky Way]] at 53 &nbsp;km/s. It mostly contains [[population II]] stars, but also has populations of young and intermediate age.<ref name=Oakes/>

===ExternalGlobular links=clusters==

Using the [[Hubble Space Telescope]], scientists derived a [[color-magnitude diagram]] for [[Fornax 4|Fornax&nbsp;4]], a globular cluster within this galaxy. Unlike the [[globular cluster]]s Fornax 1, 2, 3, and 5, which have [[horizontal branch]]es across a wide range of colors and include [[RR Lyrae variable]]s, Fornax 4 is found to have only red in its horizontal branch. Fornax 4 is also ~3 Gyr younger than the other globular clusters. The color-magnitude diagram of Fornax 4 has a strong similarity to "young" galactic globular [[Ruprecht 106]].<ref>{{cite journal |author=Buonanno, R. |display-authors=etal |title=HST photometry of the fornax dSph galaxy: cluster 4 and its field |journal=The Astronomical Journal |volume=118 |issue=4 |pages=1671–1683 |arxiv=astro-ph/9907073 |date=1 October 1999 |url=http://iopscience.iop.org/1538-3881/118/4/1671/fulltext/ |bibcode = 1999astro.ph..7073B |doi=10.1086/301034|s2cid=117753848 }}</ref>

*[http://www.astro.uu.se/~ns/fornax.html Fornax dSph]

*[http://www.seds.org/~spider/spider/LG/for_dw.html Fornax Dwarf]

It has been debated for some time whether the globular cluster Fornax 6 is a true member of the Fornax Dwarf, or merely a chance alignment of stars and/or galaxies.<ref name=Pace/> A 2021 study found it to be a true cluster and a member, but it is notably more [[metallicity|metal-rich]] and therefore likely younger than the other clusters. It is estimated to be about 2 billion years old.<ref name=Pace/>

{{Milky Way Footer}}

<gallery>

[[Category:Milky Way Subgroup]]

Heic1425a.tif|[[Hubble Space Telescope]] image of four of the globular clusters in Fornax Dwarf

[[Category:Dwarf galaxies]]

</gallery>

[[Category:Fornax constellation]]

It is not known why spheroidals allow the formation of globular clusters like Fornax 4 and [[Terzan 7]] (of [[Sagittarius Dwarf Elliptical Galaxy|Sagittarius dwarf]]) long after globular clusters ceased to form in the main body of the Galactic halo. Another possibility is that "young" globular clusters of the outer halo like Ruprecht 106 were originally formed in now defunct dwarf spheroidals.<ref name="Bergh2000">{{Cite journal

[[de:Fornax-Zwerggalaxie]]

| last1 = van den Bergh

[[sk:Trpaslíčia galaxia Pec]]

| first1 = Sidney

| author-link1 = Sidney van den Bergh

| title = Updated Information on the Local Group

| date = April 2000

| journal = The Publications of the Astronomical Society of the Pacific

| volume = 112

| issue = 770

| bibcode = 2000PASP..112..529V

| pages = 529–536

| doi = 10.1086/316548

|arxiv = astro-ph/0001040 | s2cid = 1805423

}}</ref>

==References==

{{reflist|refs =

<ref name=Pace>{{cite journal|doi=10.3847/1538-4357/ac2cd2|title=Spectroscopic Confirmation of the Sixth Globular Cluster in the Fornax Dwarf Spheroidal Galaxy|year=2021|last1=Pace|first1=Andrew B.|last2=Walker|first2=Matthew G.|last3=Koposov|first3=Sergey E.|last4=Caldwell|first4=Nelson|last5=Mateo|first5=Mario|last6=Olszewski|first6=Edward W.|last7=Bailey Iii|first7=John I.|last8=Wang|first8=Mei-Yu|journal=The Astrophysical Journal|volume=923|issue=1|page=77|arxiv=2105.00064|bibcode=2021ApJ...923...77P|s2cid=233481757 |doi-access=free }}</ref>

{{galaxy-stub}}

}}

==External links==

*{{commonscat-inline}}

*[http://www.astro.uu.se/~ns/fornax.html Fornax dSph] {{Webarchive|url=https://web.archive.org/web/20120829050712/http://www.astro.uu.se/~ns/fornax.html |date=2012-08-29 }}

*[https://web.archive.org/web/20070102142256/http://www.seds.org/~spider/spider/LG/for_dw.html Fornax Dwarf]

*{{WikiSky|name=The Fornax Dwarf}}

{{Milky Way Footer}}

{{Fornax}}

{{Sky|02|39|59.3|-|34|26|57|460000}}

{{DEFAULTSORT:Fornax Dwarf}}

[[Category:Dwarf galaxies]]

[[Category:Dwarf elliptical galaxies]]

[[Category:Local Group]]

[[Category:Milky Way Subgroup]]

[[Category:Fornax constellation]]

[[Category:Principal Galaxies Catalogue objects|10074]]

[[Category:Astronomical objects discovered in 1938|?]]