Messier 46

---

title: "Messier 46" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["open-clusters", "orion–cygnus-arm", "puppis", "messier-objects", "ngc-objects", "astronomical-objects-discovered-in-1771", "discoveries-by-charles-messier"] description: "Open cluster in the constellation Puppis" topic_path: "general/open-clusters" source: "https://en.wikipedia.org/wiki/Messier_46" 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 46
image	[[File:M46-star-cluster.png
caption	Open cluster Messier 46 and the planetary nebula NGC 2438
epoch	J2000.0
constellation	Puppis
ra
dec
dist_ly	1510 +/-
appmag_v	6.0
mass_msol
size_v
radius_ly
age	251.2 Myr
notes	contains superimposed
planetary nebula NGC 2438
names	M46, NGC 2437, Cr 159, C 0739-147, OCl 601.0
::

| name = Messier 46 | image = [[File:M46-star-cluster.png|300px]] | caption = Open cluster Messier 46 and the planetary nebula NGC 2438 | epoch = J2000.0 | constellation = Puppis | ra = | dec = | dist_ly = 1510 +/- | appmag_v = 6.0 | mass_msol = | size_v = | radius_ly = | age = 251.2 Myr | notes = contains superimposed planetary nebula NGC 2438 | names = M46, NGC 2437, Cr 159, C 0739-147, OCl 601.0

Messier 46 or M46, also known as NGC 2437, is an open cluster of stars in the slightly southern constellation of Puppis. It was discovered by Charles Messier in 1771. Dreyer described it as "very bright, very rich, very large." It is about 5,000 light-years away. There are an estimated 500 stars in the cluster with a combined mass of , and it is thought to be a mid-range estimate of 251.2 million years old.

The cluster has a very broadest (tidal) radius of 11.6 ± and core radius of 2.6 ±. It has a greater spatial extent in infrared than in visible light, suggesting it is undergoing some mass segregation with the fainter (redder) stars migrating to a coma (tail) region. The fainter stars that extend out to the south and west may form a tidal tail due to a past interaction.

The planetary nebula NGC 2438 appears to lie within the cluster near its northern edge (the faint almost rainbow array of colored smudge at the top-center of the image), but it is most likely unrelated since it does not share the cluster's radial velocity.{{cite journal | last1=Majaess | first1=D. J. | last2=Turner | first2=D. | last3=Lane | first3=D. | date=2007 | title=In Search of Possible Associations between Planetary Nebulae and Open Clusters | journal=Publications of the Astronomical Society of the Pacific | volume=119 | issue=862 | pages=1349 | arxiv=0710.2900 | bibcode=2007PASP..119.1349M | doi=10.1086/524414 | s2cid=18640979 }} | last1=Kiss | first1=L. L. | display-authors=4 | last2=Szabó | first2=Gy. M. | last3=Balog | first3=Z. | last4=Parker | first4=Q. A. | last5=Frew | first5=D. J. | title=AAOmega radial velocities rule out current membership of the planetary nebula NGC 2438 in the open cluster M46 | journal=Monthly Notices of the Royal Astronomical Society | volume=391 | issue=1 | pages=399–404 | date=2008 | arxiv=0809.0327 | bibcode= 2008MNRAS.391..399K | doi= 10.1111/j.1365-2966.2008.13899.x | doi-access=free | s2cid=15207860 }} This makes for superimposed objects of interest, another instance perhaps being NGC 2818. |author=Mermilliod, J.-C. |display-authors=4 |author2=Clariá, J. J. |author3=Andersen, J. |author4=Piatti, A. E. |author5=Mayor, M. |date=2001 |title=Red giants in open clusters. IX. NGC 2324, 2818, 3960 and 6259 |journal=Astronomy & Astrophysics |volume=375 |pages=30–39 |bibcode=2001A&A...375...30M |doi=10.1051/0004-6361:20010845 |citeseerx=10.1.1.30.7545 |s2cid=122773065 On the other hand, the illuminating star of the bipolar Calabash Nebula shares the radial velocity and proper motion of Messier 46, and is at the same distance, so is a bona fide member of the open cluster. |author=Vickers S.B. |author2=Frew D.J. |author3=Parker Q.A. |author4=Bojicic I.S. |date=2015 |title=New light on Galactic post-asymptotic giant branch stars – I. First distance catalogue |journal=Monthly Notices of the Royal Astronomical Society |volume=447 |issue=2 |pages=1673 |arxiv=1403.7230 |bibcode=2015MNRAS.447.1673V |doi=10.1093/mnras/stu2383 |doi-access=free }}

M46 is located close by to another open cluster, Messier 47.{{cite news | url=https://www.sciencedaily.com/releases/2014/12/141217074325.htm | title=The hot blue stars of messier 47 | date=17 December 2014 | publisher=ScienceDaily

References

| title=The Open Cluster NGC 2437 (Messier 46) | last1=Davidge | first1=T. J. | journal=Publications of the Astronomical Society of the Pacific | volume=125 | issue=924 | pages=115–125 | date=February 2013 | doi=10.1086/669823 | arxiv=1301.6806 | bibcode=2013PASP..125..115D | s2cid=118656815 }}

| last1=Wu | first1 =Zhen-Yu | last2=Zhou | first2 =Xu | last3=Ma | first3 =Jun | last4=Du | first4 =Cui-Hua | title=The orbits of open clusters in the Galaxy | journal=Monthly Notices of the Royal Astronomical Society | volume=399 | issue=4 | pages=2146–2164 | date=November 2009 | arxiv=0909.3737 | bibcode=2009MNRAS.399.2146W | doi=10.1111/j.1365-2966.2009.15416.x | doi-access=free | s2cid=6066790 | postscript=. }}

| title=Towards absolute scales for the radii and masses of open clusters | last1=Piskunov | first1=A. E. | last2=Schilbach | first2=E. | last3=Kharchenko | first3=N. V. | last4=Röser | first4=S. | last5=Scholz | first5=R. -D. | display-authors=1 | journal=Astronomy and Astrophysics | postscript=. | volume=468 | issue=1 | pages=151–161 | date=June 2007 | doi=10.1051/0004-6361:20077073 | bibcode=2007A&A...468..151P | arxiv=astro-ph/0702517 | s2cid=14769639 }}

References

1. (November 2023). "Messier 46".
2. "M 46".

::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. ::