Messier 47

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title: "Messier 47" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["open-clusters", "puppis", "messier-objects", "ngc-objects", "orion–cygnus-arm", "astronomical-objects-discovered-in-1654"] description: "Open cluster in the constellation Puppis" topic_path: "general/open-clusters" source: "https://en.wikipedia.org/wiki/Messier_47" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Open cluster in the constellation Puppis ::

::data[format=table title="Infobox open cluster"]

Field	Value
name	Messier 47
image	Noao-m47.jpg
caption	Open cluster Messier 47 in Puppis
credit	NOIRLab / NSF / AURA
epoch	J2000.0
ra
dec
dist_ly	498 pc
appmag_v	4.4
size_v	30
mass_msol	453
radius_ly	10.61 pc
age	78 million years
names	NGC 2422, NGC 2478, Cr 152
::

| name = Messier 47 | image = Noao-m47.jpg | caption = Open cluster Messier 47 in Puppis | credit= NOIRLab / NSF / AURA | epoch = J2000.0 | ra = | dec = | dist_ly = 498 pc | dist_pc = | appmag_v = 4.4 | size_v = 30 | mass_kg = | mass_msol = 453 | radius_ly = 10.61 pc | v_hb = | age = 78 million years | notes = | names = NGC 2422, NGC 2478, Cr 152 Messier 47 (M47 or NGC 2422), also known as NGC 2478 is an open cluster in the mildly southern constellation of Puppis. It was discovered by Giovanni Batista Hodierna before 1654 and in his then keynote work re-discovered by Charles Messier on 1771. It was also independently discovered by Caroline Herschel.

There is no cluster in the position indicated by Messier, which he expressed in terms of its right ascension and declination with respect to the star 2 Puppis. However, if the signs (+ and −) he wrote are swapped, the position matches. Until this equivalency was found, M47 was considered a lost Messier Object. This identification as the same thing (ad idem) only came in 1959 with a realization by Canadian astronomer T. F. Morris.

M47 is centered about 1,600 light-years away and is about 78 million years old. The member stars have been measured down to about red dwarfs at apparent magnitude 19. There are around 500 members, the brightest being HD 60855, a magnitude 5.7 Be star. The cluster is dominated by hot class B main sequence and giant stars, but a noticeable colour contrast comes from its brightest red giants.

It about a degree from Messier 46, which is much older and much further away.

Gallery

Eso1441a.jpg|Image of star cluster Messier 47 taken using the Wide Field Imager camera, installed on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile.

References and footnotes

| last = Houston | first = Walter Scott | author-link=Walter Scott Houston | title = Deep-Sky Wonders | publisher = Sky Publishing Corporation | year = 2005 | isbn = 978-1-931559-23-2

References

1. Stoyan, Ronald. (2008). "Atlas of the Messier Objects: Highlights of the Deep Sky". Cambridge University Press.
2. "NGC/IC Project Restoration Efforts".
3. (2003). "Luminosity and Mass Function of the Galactic open cluster NGC 2422". Astronomy & Astrophysics.
4. (17 December 2014). "The hot blue stars of messier 47". [[ScienceDaily]].

::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. ::