Article · Wikipedia archive · Last revised Jun 25, 2026

Messier 43

Messier 43 or M43, also known as De Mairan's Nebula and NGC 1982, is a star-forming nebula with a prominent H II region in the equatorial constellation of Orion. It was discovered by the French scientist Jean-Jacques d'Ortous de Mairan some time before 1731, then catalogued by Charles Messier in 1769. It is physically part of the Orion Nebula, separate from that main nebula by a dense lane of dust known as the northeast dark lane. It is part of the much larger Orion molecular cloud complex.

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Jun 25, 2026
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Messier 43
Emission nebula
H II region
Hubble Space Telescope view of M43
Observation data: J2000 epoch
Right ascension05h 35m 31.8s1
Declination−05° 17′ 57″1
Distance1,300 ± 160 ly (400 ± 50 pc) ly
Apparent magnitude (V)9.02
Apparent dimensions (V)20′ × 15′3
ConstellationOrion
Notable featuresNU Orionis
DesignationsDe Mairan's Nebula, M43, NGC 19824

Messier 43 or M43, also known as De Mairan's Nebula and NGC 1982, is a star-forming nebula with a prominent H II region in the equatorial constellation of Orion. It was discovered by the French scientist Jean-Jacques d'Ortous de Mairan some time before 1731,3 then catalogued by Charles Messier in 1769.a It is physically part of the Orion Nebula (Messier 42), separate from that main nebula by a dense lane of dust known as the northeast dark lane.5 It is part of the much larger Orion molecular cloud complex.

The main ionizing star in this nebula is the quadruple star system NU Orionis (HD 37061), the focus of the H II region, 1,360 ± 30 ly (417.0 ± 9.2 pc) away.6 This star system is not hot enough to produce significant amounts of [O III] emission, unlike the Trapezium in the Orion Nebula.7

The H II region is a roundish volume of ionized hydrogen. It has a diameter of about 4.5′, at its distance meaning it measures 2.1 ly (0.65 pc). The net (meaning omitting the star) hydrogen alpha luminosity of this region is (3.0±1.1)×1035 erg s−1; equivalent to 78 L☉. There is a dark lane crossing the whole west-centre strip from north to south, known as the M43 dark lane, which forming a swirling belt extension to the south links to Orion's northeast dark lane. All of these resemble a mixture of smoke rising from a chimney and in watercolour broad and fine dark brushstrokes, at many wavelengths.

  • Emission nebula Messier 43 to the northeast of the well-known M42 Orion Nebula
    Emission nebula Messier 43 to the northeast of the well-known M42 Orion Nebula
  • Infrared view of (part of) De Mairan's Nebula (M43)
    Infrared view of (part of) De Mairan's Nebula (M43)
  • A proplyd being ionized by HD 37061 (image with JWST).
    A proplyd being ionized by HD 37061 (image with JWST).
  • In this false color image, M43 visibly lacks [O III] emission (blue) present throughout the rest of the Orion Nebula.
    In this false color image, M43 visibly lacks [O III] emission (blue) present throughout the rest of the Orion Nebula.
See also

See also

References and footnotes

  1. Sulentic, Jack W.; et al. (1973), The revised new catalogue of nonstellar astronomical objects, Tucson: University of Arizona Press, Bibcode:1973rncn.book.....S.
  2. "Messier 43". SEDS Messier Catalog. Retrieved 23 July 2024.
  3. Adam, Len (2018), Imaging the Messier Objects Remotely from Your Laptop, The Patrick Moore Practical Astronomy Series, Springer, p. 209, Bibcode:2018imor.book.....A, ISBN 978-3319653853.
  4. "M 43". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 25, 2018.
  5. Simón-Díaz, S.; et al. (June 2011), "A detailed study of the H ii region M 43 and its ionizing star", Astronomy & Astrophysics, 530: 13, arXiv:1103.3628, Bibcode:2011A&A...530A..57S, doi:10.1051/0004-6361/201116608, A57.
  6. Aschenbrenner, P.; Przybilla, N. (2024-11-01). "Quantitative spectroscopy of multiple OB stars - I. The quadruple system HD 37061 at the centre of Messier 43". Astronomy & Astrophysics. 691: A361. arXiv:2410.23229. doi:10.1051/0004-6361/202451878. ISSN 0004-6361.
  7. Odell, C. R.; Harris, Jessica (2010-09-08). "Spectrophotometry of the Huygens Region of the Orion Nebula, the Extended Orion Nebula, and M 43: Scattered Light Systematically Distorts Conditions Derived from Emission Lines" (PDF). The Astronomical Journal. 140 (4): 985–1006. doi:10.1088/0004-6256/140/4/985 – via Space Telescope Science Institute (STScI).
External links
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