Planetary Nebula M2-9 / Butterfly Nebula

Planetary Nebula M2-9 / Butterfly Nebula

Planetary Nebula M2-9

M2-9 (also known as Wings of a Butterfly Nebula or just Butterfly Nebula, and Twin Jet Nebula) is a planetary nebula (PN). This bipolar nebula takes the peculiar form of twin lobes of material that emanate from a central star. Astronomers have dubbed this object as the Twin Jet Nebula because of the polar jets believed to cause the shape of the lobes. Its form also resembles the wings of a butterfly, for which it is sometimes referred as the Wings of a Butterfly Nebula. The outer shell is estimated to be about 1,200 (Schwarz et al. 1997) years old.

Observation data
(Epoch J2000)
Right ascension 17h 05m 37.952s[1]
Declination -10° 08′ 34.58″[1]
Distance 2,100 ly (650 pc)[2]
Apparent magnitude (V) 14.7[1]
Apparent dimensions (V) 115″[2] × 18″
Constellation Ophiuchus
Physical characteristics
Radius 0.7 ly (0.2 pc)[2][a]
Absolute magnitude (V) 5.6[b]
Notable features Bipolar outflow, Bipolar nebula
Other designations Twin Jet Nebula,[1]
Butterfly Nebula,[1]
Wings of a Butterfly[3]

M2-9 was discovered by Rudolph Minkowski in 1947. The M in M2-9 does not stand for Messier object. The nebula was imaged by the Hubble Space Telescope in the 1990s.

The Wings of a Butterfly Nebula is about 2,100 light-years away from Earth in the direction of the constellation Ophiuchus.

It represents the spectacular "last gasp"[citation needed] of a binary star system at the nebula's center. One component of this 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. Early in its life the main component of the system was believed to be a sun-like star.

This central star is one of a very closely orbiting pair - the smaller star may even have been engulfed by the other's expanding stellar atmosphere. The resulting interaction has created the stunning planetary nebula.

The nebula has inflated dramatically[4] 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.

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. Such a disk can successfully account for the jet-exhaust-like appearance of M2-9.

See also

* Bipolar nebula

* Bipolar outflow

* Planetary nebula

* Protoplanetary nebula

* Mz 3


1. ^ Radius = distance × sin(angular size / 2) = 2.1 kly * sin(115″ / 2) = 0.6 ly
2. ^ 14.7 apparent magnitude - 5 * (log10(650 pc distance) - 1) = 5.6 absolute magnitude

1. ^ a b c d e (SIMBAD 2006)
2. ^ a b c (Schwarz et al. 1997)
3. ^ (APoD 2005)
4. ^ (APoD 2007)


* APoD (June 12, 2005), Astronomy Picture of the Day, NASA and Michigan Technological University (MTU), <>

* APoD (June 18, 2007), Astronomy Picture of the Day, NASA and Michigan Technological University (MTU), <>

* Hora, Joseph L. & William B. Latter (1994), "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", Astrophysical Journal, Part 1 (ISSN 0004-637X) 437 (1): 281-295, <>

* Livio, Mario & Noam Soker (2001), "The "Twin Jet" Planetary Nebula M2-9", The Astrophysical Journal 552 (2): 685-691, <>

* Savage, Don (December 17, 1997), "Hubble Witnesses the Final Blaze of Glory of Sun-Like Stars", Space Telescope Science Institute, <>

* Schwarz, H. E.; C. Aspin & R. L. M. Corradi et al. (1997), "M 2-9: moving dust in a fast bipolar outflow", Astronomy and Astrophysics 319: 267-273, <>

* SIMBAD (December 22, 2006), Results for PN M 2-9, SIMBAD, Centre de Données Astronomiques de Strasbourg, <>


* NASA APoD 1997-12-23 & APoD 1999-03-21 & APoD 2004-02-01 & APoD 2005-06-12 & APoD 2007-06-18 M2-9: Wings of a Butterfly Nebula

Retrieved from ""
All text is available under the terms of the GNU Free Documentation License