NGC 2506
Open cluster in the constellation Monoceros
title: "NGC 2506" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["open-clusters", "monoceros", "ngc-objects", "caldwell-objects", "astronomical-objects-discovered-in-1791"] description: "Open cluster in the constellation Monoceros" topic_path: "general/open-clusters" source: "https://en.wikipedia.org/wiki/NGC_2506" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Open cluster in the constellation Monoceros ::
::data[format=table title="Infobox open cluster"]
| Field | Value |
|---|---|
| name | NGC 2506 |
| image | File:NGC 2506 composite.png |
| caption | A composite image of NGC 2506 from multiple astronomical surveys |
| epoch | J2000 |
| ra | |
| dec | |
| dist_ly | 3.88 ± |
| appmag_v | 7.6 |
| size_v | |
| radius_ly | |
| age | Gyr |
| constellation | Monoceros |
| names | Caldwell 54, Cr 170, Mel 80 |
| :: |
| name = NGC 2506 | image = File:NGC 2506 composite.png | caption = A composite image of NGC 2506 from multiple astronomical surveys | credit = | epoch = J2000 | ra = | dec = | dist_ly = 3.88 ± | appmag_v = 7.6 | size_v = | radius_ly = | absmag_v = | mass_msol = | age = Gyr | constellation = Monoceros | notes = | names = Caldwell 54, Cr 170, Mel 80 ::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/2e/NGC_2506_map.png" caption="Map showing the location of NGC 2506"] ::
NGC 2506 (also known as Caldwell 54) is a mildly-elongated open cluster of stars in the equatorial constellation of Monoceros, located at a distance of 3.88 kpc from the Sun near the Galactic anti-center. It was discovered by William Herschel in 1791. The cluster lies around from the Galactic Center and about above the Galactic plane. It is of intermediate age, estimated at around two billion years. The cluster has an angular radius of and a core radius of .
At least 94 probable members have been identified within the field of NGC 2506 based upon their radial velocities. Compared to the Sun, the cluster is moderately metal-poor with an iron abundance of [Fe/H] = –0.3 dex. It shows indications of mass segregation, with the lower mass members being more likely to be in the outer parts of the cluster. This is the result of exchange of kinetic energy during encounters between the members. Twelve blue straggler stars have been located in the cluster, with three of them showing short-period oscillation. Fourteen Gamma Doradus variables have been found, as well as two detached eclipsing binaries, and three Delta Scuti stars.
References
| title= NGC 2506 | access-date=2010-11-28 }}
| title=Deep-Sky Companions: The Caldwell Objects | first=Stephen James | last=O'Meara | edition=2nd | publisher=Cambridge University Press | year=2016 | isbn=9781316033531 | page=251 | url=https://books.google.com/books?id=evkODQAAQBAJ&pg=PA251 }}
| title=Search for Variable Stars in Two Old Open Clusters: NGC2506 and NGC2420 | last1=Kim | first1=S. -L. | last2=Chun | first2=M. -Y. | last3=Park | first3=B. -G. | last4=Kim | first4=S. C. | last5=Lee | first5=S. H. | last6=Lee | first6=M. G. | last7=Ann | first7=H. B. | last8=Sung | first8=H. | last9=Jeon | first9=Y. -B. | last10=Yuk | first10=I. -S. | display-authors=1 | journal=Acta Astronomica | volume=51 | pages=49–63 | date=March 2001 | bibcode=2001AcA....51...49K }}
| title=Oscillating blue stragglers, γ Doradus stars and eclipsing binaries in the open cluster NGC 2506 | last1=Arentoft | first1=T. | last2=De Ridder | first2=J. | last3=Grundahl | first3=F. | last4=Glowienka | first4=L. | last5=Waelkens | first5=C. | last6=Dupret | first6=M. -A. | last7=Grigahcène | first7=A. | last8=Lefever | first8=K. | last9=Jensen | first9=H. R. | last10=Reyniers | first10=M. | last11=Frandsen | first11=S. | last12=Kjeldsen | first12=H. | display-authors=1 | journal=Astronomy and Astrophysics | volume=465 | issue=3 | pages=965–979 | date=April 2007 | doi=10.1051/0004-6361:20066931 | arxiv=astro-ph/0703111 | bibcode=2007A&A...465..965A | s2cid=119364668 }}
| title=Deep and wide photometry of two open clusters NGC 1245 and NGC 2506: dynamical evolution and halo | display-authors=1 | last1=Lee | first1=S. H. | last2=Kang | first2=Y. -W. | last3=Ann | first3=H. B. | journal=Monthly Notices of the Royal Astronomical Society | volume=432 | issue=2 | pages=1672–1679 | date=June 2013 | doi=10.1093/mnras/stt588 | doi-access=free | arxiv=1304.1967 | bibcode=2013MNRAS.432.1672L }}
| title=WIYN Open Cluster Study. LXXVI. Li Evolution Among Stars of Low/Intermediate Mass: The Metal-deficient Open Cluster NGC 2506 | last1=Anthony-Twarog | first1=Barbara J. | last2=Lee-Brown | first2=Donald B. | last3=Deliyannis | first3=Constantine P. | last4=Twarog | first4=Bruce A. | display-authors=1 | journal=The Astronomical Journal | volume=155 | issue=3 | id=138 | pages=21 | date=March 2018 | doi=10.3847/1538-3881/aaad66 | arxiv=1802.03447 | bibcode=2018AJ....155..138A | s2cid=118974536 | doi-access=free }}
| last1=Xin | first1=Y. | last2=Deng | first2=L. | title=Blue Stragglers in Galactic Open Clusters and Integrated Spectral Energy Distributions | journal=The Astrophysical Journal | volume=619| issue=2 | pages=824–838 | date=February 2005 | doi=10.1086/426681 | arxiv=astro-ph/0410325 | bibcode=2005ApJ...619..824X | s2cid=2087723 }}
| last1=Kharchenko | first1=N. V. | last2=Piskunov | first2=A. E. | last3=Röser | first3=S. | last4=Schilbach | first4=E. | last5=Scholz | first5=R.-D. | display-authors=1 | title=Astrophysical parameters of Galactic open clusters | journal=Astronomy and Astrophysics | volume=438 | issue=3 | pages=1163–1173 | year=2005 | bibcode=2005A&A...438.1163K | arxiv=astro-ph/0501674 | doi=10.1051/0004-6361:20042523 | s2cid=9079873 }}
| title=Astrometric and photometric study of NGC 6067, NGC 2506, and IC 4651 open clusters based on wide-field ground and Gaia DR2 data | display-authors=1 | last1=Rangwal | first1=Geeta | last2=Yadav | first2=R. K. S. | last3=Durgapal | first3=Alok | last4=Bisht | first4=D. | last5=Nardiello | first5=D. | journal=Monthly Notices of the Royal Astronomical Society | volume=490 | issue=1 | pages=1383–1396 | date=November 2019 | doi=10.1093/mnras/stz2642 | doi-access=free | arxiv=1909.08810 | bibcode=2019MNRAS.490.1383R }}
| first=Robert E. | last=Erdmann | title=NGC Discoverers | work=The NGC/IC Project | url=http://www.ngcicproject.org/erdmann/NGC_Discoverers_01.txt | access-date=2010-11-28 | url-status=dead | archive-url=https://web.archive.org/web/20110228034511/http://www.ngcicproject.org/erdmann/NGC_Discoverers_01.txt | archive-date=2011-02-28 }}
| title=SEDS NGC Catalog Online | work=Results for NGC 2506 | url=http://spider.seds.org/ngc/ngc.cgi?2506 | access-date=2010-11-28 }}
::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. ::