NGC 2204
Open cluster in the constellation Canis Major
title: "NGC 2204" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["canis-major", "open-clusters", "ngc-objects", "discoveries-by-william-herschel"] description: "Open cluster in the constellation Canis Major" topic_path: "general/canis-major" source: "https://en.wikipedia.org/wiki/NGC_2204" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Open cluster in the constellation Canis Major ::
::data[format=table title="Infobox open cluster"]
| Field | Value |
|---|---|
| name | NGC 2204 |
| image | NGC 2204 DSS.jpg |
| caption | NGC 2204, Digitized Sky Survey |
| constellation | Canis Major |
| epoch | J2000.0 |
| ra | |
| dec | |
| dist_ly | 4.1 ± |
| appmag_v | 8.6 |
| size_v | |
| radius_ly | 16.25ly |
| age | |
| names | Collinder 88, Melotte 44 |
| :: |
| name = NGC 2204 | image = NGC 2204 DSS.jpg | caption = NGC 2204, Digitized Sky Survey | constellation = Canis Major | epoch = J2000.0 | ra = | dec = | dist_ly = 4.1 ± | dist_pc = | appmag_v = 8.6 | size_v = | mass_msol = | radius_ly = 16.25ly | age = | notes = | names = Collinder 88, Melotte 44
NGC 2204 is an open cluster of stars in the Canis Major constellation. It was discovered by the German-English astronomer William Herschel on 6 February 1785. The cluster has an integrated visual magnitude of 8.6 and spans a diameter of . Resolving the individual member stars is a challenge with a 10 to 12-inch amateur telescope. It is located at a distance of approximately 13,400 light years from the Sun. The cluster shows a mean radial velocity of relative to the Sun, and is orbiting the inner galactic disk region about 1 kpc below the galactic plane.
This is a rich but diffuse cluster with a Trumpler class of III 3m, spanning a physical diameter of about 17 pc. It is an older cluster with an estimated age of . The metallicity is correspondingly poor, showing an abundance of iron about 59% of that in the Sun. There is a prominent giant branch clump on the HR diagram. The cluster has a significant population of blue stragglers, an indicator of past stellar mergers. It has a pair of candidate chemically peculiar stars, and five variable stars have been discovered, including four eclipsing variables.
References
| title=NGC 2204 | access-date=2024-03-09 }}
| title=3D kinematics and age distribution of the open cluster population | display-authors=1 | last1=Tarricq | first1=Y. | last2=Soubiran | first2=C. | last3=Casamiquela | first3=L. | last4=Cantat-Gaudin | first4=T. | last5=Chemin | first5=L. | last6=Anders | first6=F. | last7=Antoja | first7=T. | last8=Romero-Gómez | first8=M. | last9=Figueras | first9=F. | last10=Jordi | first10=C. | last11=Bragaglia | first11=A. | last12=Balaguer-Núñez | first12=L. | last13=Carrera | first13=R. | last14=Castro-Ginard | first14=A. | last15=Moitinho | first15=A. | last16=Ramos | first16=P. | last17=Bossini | first17=D. | journal=Astronomy & Astrophysics | volume=647 | at=id. A19 | date=March 2021 | doi=10.1051/0004-6361/202039388 | arxiv=2012.04017 | bibcode=2021A&A...647A..19T }}
| title=A Chemical Abundance Study of Red Giants in Open Clusters NGC 2204 and NGC 2243 | display-authors=1 | last1=Jacobson | first1=Heather R. | last2=Friel | first2=Eileen D. | last3=Pilachowski | first3=Catherine A. | journal=The Astronomical Journal | volume=141 | issue=2 | id=58 | pages=16 | date=February 2011 | doi=10.1088/0004-6256/141/2/58 | bibcode=2011AJ....141...58J | s2cid=120444023 | doi-access=free }}
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| title=NGC 2204: an old open cluster in the halo | last=Hawarden | first=T. G. | journal=Monthly Notices of the Royal Astronomical Society | volume=174 | pages=225–239| date=January 1976 | doi=10.1093/mnras/174.1.225 | doi-access=free | bibcode=1976MNRAS.174..225H }}
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::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::