Messier 43
Template:Short description Template:Infobox nebula
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,<ref name=Adam2018/> then catalogued by Charles Messier in 1769.Template:Efn 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.<ref name=Diaz2011/> It is part of the much larger Orion molecular cloud complex.
The main ionizing star in this nebula is HD 37061 (variable star designation NU OriTemplate:Efn), the focus of the H II region, Template:Convert away.Template:Efn This is a triple star system with the brighter component being a single-lined spectroscopic binary. The main component is a blue-white hued B-type main-sequence star with a stellar classification of B0.5V or B1V. It has Template:Val times the mass of the Sun (Template:Solar mass) and Template:Val times the Sun's radius (Template:Solar radius). It is radiating over 26,000 times the Sun's luminosity (Template:Lo) from its photosphere at an effective temperature of 31,000 K. It is spinning rapidly with a projected rotational velocity of around 200 km/s.<ref name=Diaz2011/>
The H II region is a roundish volume of ionized hydrogen. It has a diameter of about Template:Val, at its distance meaning it measures Template:Convert. The net (meaning omitting the star) hydrogen alpha luminosity of this region is Template:Val; equivalent to Template:Val. 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.
GalleryEdit
- Messier 43 HST.jpg
Infrared view of (part of) De Mairan's Nebula (M43)