Messier 43 or M43, also known as De Mairan's Nebula and NGC 1982, is a star-forming

nebula A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...

with a prominent

H II region An H II region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light year ...

in the equatorial

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Orion Orion may refer to: Common meanings * Orion (constellation), named after the mythical hunter * Orion (mythology), a hunter in Greek mythology Arts and media Fictional entities Characters and species * Orion (character), a DC Comics c ...

. It was discovered by the French scientist

Jean-Jacques d'Ortous de Mairan Jean-Jacques d'Ortous de Mairan (26 November 1678 – 20 February 1771) was a French natural philosopher (physicist), born in the town of Béziers on 26 November 1678. De Mairan lost his father, François d'Ortous, at age four and his mother tw ...

some time before 1731, then catalogued by

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects'', referred to with th ...

in 1769. It is physically part of the

Orion Nebula The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula in the Milky Way situated south of Orion's Belt in the Orion (constellation), constellation of Orion, and is known as the middle "star" in the "sword" of Orion. It ...

(Messier 42), separate from that main nebula by a dense lane of

dust Dust is made of particle size, fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian processes, aeolian process), Types of volcan ...

known as the northeast dark lane. It is part of the much larger

Orion molecular cloud complex The Orion molecular cloud complex (or, simply, the Orion complex) is a star-forming region with stellar ages ranging up to 12 Myr. Two Molecular cloud#Giant molecular clouds, giant molecular clouds are a part of it, Orion A and Orion B. The stars ...

. The main

ionizing Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule i ...

star in this nebula is HD 37061 (

variable star designation In astronomy, a variable-star designation is a unique identifier given to variable stars. It extends the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constellation in whic ...

NU Ori), the focus of the H II region, away. This is a triple star system with the brighter component being a single-lined

spectroscopic binary A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

. The main component is a blue-white hued

B-type main-sequence star A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars ...

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

of B0.5V or B1V. It has times the

mass of the Sun The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...

() and times the

Sun's radius Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\ti ...

(). It is radiating over 26,000 times the

Sun's luminosity The solar luminosity () is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal s ...

() from its

photosphere The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...

at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 31,000 K. It is spinning rapidly with a

projected rotational velocity Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bu ...

of around 200 km/s. The H II region is a roundish volume of ionized hydrogen. It has a diameter of about , at its distance meaning it measures . The net (meaning omitting the star)

hydrogen alpha Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emit ...

luminosity of this region is ; equivalent to . 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.

Gallery

File:Messier 43 HST.jpg, Infrared view of (part of) De Mairan's Nebula (M43) File:Proplyd 332-1605 JWST.jpg, A

proplyd A proplyd, syllabic abbreviation, short for ionized protoplanetary disk, is an externally illuminated Photoevaporation, photoevaporating protoplanetary disk around a Young stellar object, young star. Nearly 180 proplyds have been discovered in the ...

being ionized by HD 37061 (image with

JWST The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, di ...

References and footnotes

External links

* * * {{Ngc20 Messier 043 Messier 043 Orion–Cygnus Arm Messier 043 043 Messier 043

Gallery

See also

References and footnotes

External links