NGC 2346

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title: "NGC 2346" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["planetary-nebulae", "spectroscopic-binaries", "monoceros", "ngc-objects"] description: "Planetary nebula in the constellation Monoceros" topic_path: "general/planetary-nebulae" source: "https://en.wikipedia.org/wiki/NGC_2346" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Planetary nebula in the constellation Monoceros ::

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

Field	Value
image	[[Image:NGC2346.jpg
caption	NGC 2346 imaged by the Hubble Space Telescope
name	NGC 2346
epoch	J2000.0
constellation	Monoceros
ra
dec
dist_ly	1458 pc
type	Planetary
appmag_v	9.6
size_v
radius_ly	2
names	Butterfly Nebula, Bug Nebula
::

| image = [[Image:NGC2346.jpg|300px]] | caption = NGC 2346 imaged by the Hubble Space Telescope | name = NGC 2346 | epoch = J2000.0 | constellation = Monoceros | ra = | dec = | dist_ly = 1458 pc | type = Planetary | appmag_v = 9.6 | size_v = | radius_ly = 2 | absmag_v = | notes = | names = Butterfly Nebula, Bug Nebula

NGC 2346 is a planetary nebula near the celestial equator in the constellation of Monoceros, less than a degree to the ESE of Delta Monocerotis. It is informally known as the Butterfly Nebula. The nebula is bright and conspicuous with a visual magnitude of 9.6, and has been extensively studied. Among its most remarkable characteristics is its unusually cool central star, which is a spectroscopic binary, and its unusual shape.

The nebular is bipolar in form, with modest outflow velocities in the range of 8–11 km/s, while the center is girded by an expanding belt of molecular gas. The electron density of the nebula is on the order of 400 per cubic centimeter. The ionization of the nebula is the result of ultraviolet emission from the binary companion. The stronger infrared emission from molecular emission is coming from the belt, which is expanding at the rate of . The mass of the molecular gas in the nebula is estimated to be in the range of 0.34–, and is much greater than the mass of the ionized gas.

The central star is a binary star consisting of an A-type subgiant and a subdwarf O star. The system, which has an orbital period of days, is also variable, probably due to dust in orbit around it. The dust itself is heated by the central star and so NGC 2346 is unusually bright in the infrared part of the spectrum. When one of the two stars evolved into a red giant, it engulfed its companion, which stripped away a ring of material from the larger star's atmosphere. When the red giant's core was exposed, a fast stellar wind inflated two ‘bubbles’ from either side of the ring.

Gallery

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c8/N2346.jpg" caption="NGC 2346 imaged with a 32-inch telescope"] ::

References

| display-authors=1 | last1=Stanghellini | first1=Letizia | last2=Shaw | first2=Richard A. | last3=Villaver | first3=Eva | title=The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale | journal=The Astrophysical Journal | date=December 10, 2008 | volume=689 | issue=1 | pages=194–202 | doi=10.1086/592395 | arxiv=0807.1129 | bibcode=2008ApJ...689..194S | s2cid=119257242 }}

| title=General catalogue of variable stars | last1=Samus' | first1=N. N | last2=Kazarovets | first2=E. V | last3=Durlevich | first3=O. V | last4=Kireeva | first4=N. N | last5=Pastukhova | first5=E. N | journal=Astronomy Reports | volume=61 | issue=1 | pages=80 | year=2017 | version=5.1 | doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=255195566 }}

| title=On the post-common-envelope central star of the planetary nebula NGC 2346 | last1=Brown | first1=Alex J. | last2=Jones | first2=David | last3=Boffin | first3=Henri M. J. | last4=Van Winckel | first4=Hans | journal=Monthly Notices of the Royal Astronomical Society | volume=482 | issue=4 | pages=4951–4955 | date=February 2019 | doi=10.1093/mnras/sty2986 | doi-access=free | arxiv=1810.09764 | bibcode=2019MNRAS.482.4951B }}

| title=Kinematics of the Molecular Hydrogen from the Planetary Nebula NGC 2346 | last1=Arias | first1=L. | last2=Rosado | first2=M. | last3=Salas | first3=L. | last4=Cruz-González | first4=I. | display-authors=1 | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3293–3304 | date=December 2001 | doi=10.1086/324446 | bibcode=2001AJ....122.3293A | doi-access=free }}

| title=Extinction Mapping of the Bipolar Outflow NGC 2346 | last1=Phillips | first1=J. P. | last2=Cuesta | first2=L. | journal=The Astronomical Journal | volume=119 | issue=1 | pages=335–341 | date=January 2000 | doi=10.1086/301170 | bibcode=2000AJ....119..335P | doi-access=free }}

| first1=Roger W. | last1=Sinnott | first2=Michael A. C. | last2=Perryman | title=Millennium Star Atlas | page=249 | volume=1 | year=1997 | isbn=0-933346-84-0 | publisher=Sky Publishing Corporation and the European Space Agency }}

| title=First Light and Beyond: Making a Success of Astronomical Observing | first=D. A. | last=Jenkins | date=July 28, 2015 | page=216 | isbn=9783319188515 | publisher=Springer International Publishing | url=https://books.google.com/books?id=d9dECgAAQBAJ&pg=PA216 }}

| website=Astronomy Picture of the Day | date=October 28, 2001 | url=https://apod.nasa.gov/apod/ap011028.html | title=NGC 2346: A Butterfly-Shaped Planetary Nebula | access-date=2020-08-28 }}

References

1. (2021). "Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity". Astronomy & Astrophysics.
2. {{Cite Gaia DR2. 3109444657456300288

::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. ::