View source for M2-9

{{Short description|Planetary nebula}}
{{Other uses of|Butterfly Nebula|Butterfly Nebula (disambiguation)}}

{{ Planetary nebula
| image = [[File:The Twin Jet Nebula.jpg|300px]]
| caption = M2-9 as taken by the [[Hubble Space Telescope]]
| name = Minkowski 2-9 (M2-9)
| type = Planetary 
| epoch = [[J2000]]
| ra = {{RA|17|05|37.952}}<ref name="simbad">{{Harv|SIMBAD|2006}}</ref>
| dec = {{DEC|-10|08|34.58}}<ref name="simbad" />
| dist_ly = 2,100 [[light year|ly]] (650 [[parsec|pc]])<ref name = "Schwarz">{{Harv|Schwarz|Aspin|Corradi|Reipurth|1997}}</ref>
| appmag_v = 14.7<ref name="simbad"/>
| size_v = 115{{pprime}}<ref name="Schwarz"/> × 18{{pprime}}{{Citation needed|date=February 2007}}
| constellation = [[Ophiuchus]]
| radius_ly = 0.7 ly (0.2 pc)<ref name="Schwarz"/><ref group="n">Radius = distance × sin(angular size / 2) = 2.1 kly * sin(115{{pprime}} / 2) = 0.6 ly</ref>
| notes = [[Bipolar outflow]], [[Bipolar nebula]]
| names = Twin Jet Nebula,<ref name="simbad"/><br>
Butterfly Nebula,<ref name="simbad"/><br>
PNG 010.8+18.0<br/>
PK 010+18.2
}}

'''Minkowski 2-9''', abbreviated '''M2-9''' (also known as '''Minkowski's Butterfly''', '''Twin Jet Nebula''', the '''Wings of a Butterfly Nebula''', or just '''Butterfly Nebula''') is a [[planetary nebula]] that was discovered by [[Rudolph Minkowski]] in 1947.  It is located about 2,100 [[light-years]] away from Earth in the direction of the constellation [[Ophiuchus]].  This [[bipolar nebula]] takes the peculiar form of twin [[wikt:lobe|lobes]] of material that emanate from a [[white dwarf|central star]].  [[Astronomer]]s have dubbed this object as the ''Twin Jet Nebula'' because of the [[astrophysical jet|jets]] believed to cause the shape of the lobes. Its form also resembles the wings of a [[butterfly]].  The nebula was imaged by the [[Hubble Space Telescope]] in the 1990s.

The primary component of the central binary is the hot core of a star that reached the end of its main-sequence life cycle, ejected most of its outer layers and became a [[red giant]], and is now contracting into a [[white dwarf]].  It is believed to have been a sun-like star early in its life.  The second, smaller star of the binary orbits very closely and may even have been engulfed by the other's expanding stellar atmosphere with the resulting interaction creating the nebula. Astronomers theorize that the gravity of one star pulls some of the gas from the surface of the other and flings it into a thin, dense disk extending into space.<ref>{{cite journal|last1=Lykou|first1=F.|display-authors=4|last2=Chesneau|first2=O.|last3=Zijlstra|first3=A. A.|last4=Castro-Carrizo|first4=A.|last5=Lagadec|first5=E.|last6=Balick|first6=B.|last7=Smith|first7=N.|date=3 Feb 2011|title=A disc inside the bipolar planetary nebula M2-9|url=http://www.aanda.org/articles/aa/abs/2011/03/aa13845-09/aa13845-09.html|journal=Astronomy & Astrophysics|publisher=EDP Sciences|volume=527|issue=A105|pages=A105 |doi=10.1051/0004-6361/200913845|accessdate=10 February 2014|arxiv = 1011.5671 |bibcode = 2011A&A...527A.105L |s2cid=36920104 }}</ref> As the central binary orbits with a period of about 86 to 120 years, the wind emitting from the binary changes direction with it.<ref>{{cite journal|doi=10.1093/pasj/psac020|title=The symbiotic and bipolar nebula M 2-9: Morphological variability of the collimated ionized wind arising from the core |year=2022 |last1=de la Fuente |first1=Eduardo |last2=Trinidad |first2=Miguel A. |last3=Tafoya |first3=Daniel |last4=Toledano-Juárez |first4=Ivan |last5=García-Flores |first5=Samuel |journal=Publications of the Astronomical Society of Japan |volume=74 |issue=3 |pages=594–601 |bibcode=2022PASJ...74..594D|arxiv=2203.00881}}</ref>

The nebula has inflated dramatically<ref name="APoD2007">{{Harv|Nemiroff|Bonnell|2007}}</ref> due to a fast [[stellar wind]], blowing out into the surrounding disk and inflating the large, wispy [[hourglass-shaped]] wings perpendicular to the disk. These wings produce the butterfly appearance when seen in projection.  The outer shell is estimated to be about 1,200 years old {{Harv|Schwarz|Aspin|Corradi|Reipurth|1997}}.
[[File:2003 BUTTERFLY NEBULA SWIRL.ogg|thumb|left|3D simulated flyaround]][[File:NEB SWIRL.ogv|thumb|left|Another 3D simulated flyaround]]
{{clear}}
<!-- Deleted image removed: [[Image:M2-9motivo corradi.gif|thumb|300px|An animated gif of the precessing jet in M2-9 [http://antwrp.gsfc.nasa.gov/apod/ap070618.html]]] -->

== Notes ==
{{Reflist|group="n"}}

== References ==
{{Reflist}}
{{refbegin}}
* {{Cite APOD
 | title = M2-9: Wings of a Butterfly Nebula
 | date = June 12, 2005
 | access-date = }}
* {{Cite APOD
 | title = Monitoring M2-9
 | date = June 18, 2007
 | access-date = }}
* {{Citation
 | last1 = Hora | first1 = Joseph L. | last2 = Latter | first2 = William B.
 | title = The near-infrared structure and spectra of the bipolar nebulae M2-9 and AFGL 2688: The role of ultraviolet pumping and shocks in molecular hydrogen excitation
 | journal = The Astrophysical Journal
 | date = 1994 | volume = 437 | issue = 1 | pages = 281–295
 | doi=10.1086/174995 | bibcode=1994ApJ...437..281H
|arxiv = astro-ph/9408011 | s2cid = 119525312 }}
* {{Citation
 | last1 = Livio | first1 = Mario | last2 = Soker | first2 = Noam
 | title = The "Twin Jet" Planetary Nebula M2-9
 | journal = The Astrophysical Journal
 | date = 2001 | volume = 552 | issue = 2 | pages = 685–691
 | authorlink = Mario Livio
 | url = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001ApJ...552..685L
 | arxiv = astro-ph/0010241 |bibcode = 2001ApJ...552..685L |doi = 10.1086/320567 | s2cid = 16212439 }}
* {{Citation
 | last = Savage | first = Don
 | title = Hubble Witnesses the Final Blaze of Glory of Sun-Like Stars
 | journal = Space Telescope Science Institute
 | date = December 17, 1997
 | url = http://hubblesite.org/newscenter/newsdesk/archive/releases/1997/38/text/
}}
* {{Citation
 | last1 = Schwarz | first1 = H. E. | last2 = Aspin | first2 = C.
 | last3 = Corradi | first3 = R. L. M. | last4 = Reipurth | first4 = B.
 | title = M 2-9: moving dust in a fast bipolar outflow
 | journal = Astronomy and Astrophysics
 | date = 1997 | volume = 319 | pages = 267–273
 | url = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997A%26A...319..267S
|bibcode = 1997A&A...319..267S }}
* {{Citation
 | last = SIMBAD
 | title = Results for PN M 2-9
 | authorlink = SIMBAD
 | date = December 22, 2006
 | publisher = SIMBAD, Centre de Données Astronomiques de Strasbourg
 | url = http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=PN+M2-9
}}
{{refend}}

{{Commons category inline|bullet=none|M2-9}}
{{sky|17|05|37.95|-|10|08|34.58|2100}}

[[Category:Planetary nebulae]]
[[Category:Ophiuchus]]
[[Category:Articles containing video clips]]