Messier 39

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title: "Messier 39" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["open-clusters", "orion–cygnus-arm", "cygnus-(constellation)", "messier-objects", "ngc-objects", "astronomical-objects-discovered-in-1764"] description: "Open cluster in the constellation Cygnus" topic_path: "general/open-clusters" source: "https://en.wikipedia.org/wiki/Messier_39" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Open cluster in the constellation Cygnus ::

::data[format=table title="Infobox Cluster"]

Field	Value
name	Messier 39
image	[[File:M39-Star-Cluster.png
caption	Messier 39 contains bright, young B-type blue giant stars
epoch	J2000
constellation	Cygnus
ra
dec
dist_ly	311 pc
appmag_v	4.6
size_v	29′
mass_msol
age	278.6 Myr
names	M 39, NGC 7092, Cr 438
::

| name = Messier 39 | image= [[File:M39-Star-Cluster.png|300px]] | caption = Messier 39 contains bright, young B-type blue giant stars | epoch = J2000 | constellation = Cygnus | ra = | dec = | dist_ly = 311 pc | appmag_v = 4.6 | size_v = 29′ | mass_msol = | age= 278.6 Myr | notes = | names = M 39, NGC 7092, Cr 438

Messier 39 or M39, also known as NGC 7092, is an open cluster of stars in the constellation of Cygnus, sometimes referred to as the Pyramid Cluster. It is positioned two degrees south of the star Pi Cygni and around 9° east-northeast of Deneb. The cluster was discovered by Guillaume Le Gentil in 1749, then Charles Messier added it to his catalogue in 1764. When observed in a small telescope at low power the cluster shows around two dozen members but is best observed with binoculars. It has a total integrated magnitude (brightness) of 4.6 and spans an angular diameter of – about the size of the full Moon. It is centered about 311 pc away.

This cluster has an estimated mass of and a linear tidal radius of . Of the 15 brightest components, six form binary star systems; one more is suspected. HD 205117 is a probable eclipsing binary system with a period of 113.2 days that varies by 0.051 in visual magnitude. Both members seem to be subgiants. Within are at least five chemically peculiar stars and ten suspected short-period variable stars.

Map

::figure[src="https://upload.wikimedia.org/wikipedia/commons/9/98/M39map.png" caption="Map"] ::

References

References

1. "Messier 39".
2. "M 39".

::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. ::