The Becklin–Neugebauer Object (BN) is an object visible only in the

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from aroun ...

in the Orion molecular cloud 1 (OMC1). It was discovered in 1967 by Eric Becklin and Gerry Neugebauer during their

near-infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

survey of the

Orion Nebula The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the Orion (constellation), constellation of Orion. It is one of the brightest nebulae and is visible to t ...

. A faint glow around the center-most stars can be observed in the visible light spectrum, especially with the aid of a telescope. The BN Object is thought to be an intermediate-mass

protostar A protostar is a very young star that is still gathering mass from its parent molecular cloud. The protostellar phase is the earliest one in the process of stellar evolution. For a low-mass star (i.e. that of the Sun or lower), it lasts about ...

. It was the first star detected using infrared methods and is deeply embedded within the Orion star-forming

nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ 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 regio ...

, where it is invisible at optical wavelengths because the light is completely scattered or absorbed due to the high density of dusty material. Near-infrared

polarized light Polarization ( also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of t ...

observations showed that the star BN is still surrounded by a

circumstellar disk A circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the re ...

Past ejection of BN

BN moves towards the northwest with respect to other stars in the Kleinmann-Low nebula. A

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

of between 21 and 27 km/s in the northwest region and a redshift of about 11 km/s with respect to the OMC1 was measured for this star. BN is therefore considered a runaway star. It was proposed that Theta1Ori C ejected BN about 4000 years ago, but it is more likely that BN and two other runaway stars, called Source I (Src I) and Source n (Src n), were ejected from a position about 500 years ago. Source I and Source n both move in opposite directions, away from BN. With more recent

VLA VLA or vla may refer to: Organizations * Vermont Library Association, professional organization for librarians from Vermont * Veterinary Laboratories Agency, a UK government agency for researching animal and public health * Victoria Legal Aid, a ...

proper motion measurements it was realised that at least six compact sources recede from a common point: BN, source I, Orion MR (formerly source n), X, IRc23 and Zapata 11. Almost all these sources were ejected about 500 years ago. The ejection of BN and source I was proposed to have occurred in the year 1475±6 (about 550 years ago). IRc23 was ejected only 300 years ago. At the time of the ejection four or more protostars dynamically interacted with each other, leading to the ejection of the stars in different directions. In the classical three-body scenario, the dynamical interaction either formed a compact binary or the

merger Mergers and acquisitions (M&A) are business transactions in which the ownership of companies, other business organizations, or their operating units are transferred to or consolidated with another company or business organization. As an aspect ...

of two stars. The large number of ejected stars suggest a more complex interaction, such as the interaction of a tight binary with a compact

star cluster Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clus ...

. This dynamical interaction released a large amount of energy, causing an infrared-only flare on the scale of a

nova A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...

or supernova with an energy of about 10⁴⁸ erg. Alternatively the explosion was not a multi-system interaction but a supernova.

Explosion remnant

The remnant of the explosion is called Kleinmann-Low nebula. Multi-wavelength observations and

carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

(CO) observations with

ALMA Alma or ALMA may refer to: Arts and entertainment * ''Alma'' (film), a 2009 Spanish short animated film * ''Alma'' (Oswald de Andrade novel), 1922 * ''Alma'' (Le Clézio novel), 2017 * ''Alma'' (play), a 1996 drama by Joshua Sobol about Alma ...

reveal the mostly spherical remnant of an explosion at the intersection point of the BN object and Source I. The ALMA observations revealed hundreds of CO streamers moving with up to 100 km/s. Some of these CO streamers nearly reach the shocked gas and dust observed in

molecular hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, ...

and

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

e II E, or e, is the fifth letter and the second vowel letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''e'' (pronounced ); plura ...

Becklin's star

Becklin's star (IRC -10093) is located at 5h 35.3m / -5° 23', very near the Becklin-Neugebauer object.''Sky Catalogue 2000.0, Volume 2: Double Stars, Variable Stars and Nonstellar Objects - Glossary of Selected Astronomical Names'', page xlv

Gallery

File:Becklin-Neugebauer object JHK.jpg, The BN object (bright star in the center) in near-infrared with ESO HAWKI. File:ESO-M42-Phot-03a-01.jpg, Near-infrared view of the central region of the

. In the center is the Trapezium cluster and the red region above contains the BN object. File:ALMA views a stellar explosion in Orion.jpg, Complete view of the ALMA, Gemini and VLT image showing the explosion remnant. The stars in the lower-left are the Trapezium cluster. File:Orion Bullets with GeMS.jpg, Part of the explosion (fingers) in the northern/northwestern part with Gemini. Iron is blue and molecular hydrogen is orange in this image. File:Jwst nircam Kleinmann-Low East.png, Part of the explosion in the eastern part with JWST NIRCam. All filters used mapped molecular hydrogen.

References

Becklin-Neugebauer object (Encyclopædia Britannica)
* * * * {{DEFAULTSORT:Becklin-Neugebauer Object Orion (constellation) Orion molecular cloud complex Star formation Protostars Orionis, V2254