Red Rectangle nebula
Encyclopedia
The Red Rectangle Nebula, so called because of its red color and unique rectangular shape, is a protoplanetary nebula
in the Monoceros constellation. Also known as HD 44179, the nebula was discovered in 1973 during a rocket flight associated with the AFCRL Infrared Sky Survey called Hi Star. The binary system
at the center of the nebula was first discovered by Robert Grant Aitken
in 1915.
with X-shaped spikes which imply toroidal dispersion of the circumstellar material. The central binary system is completely obscured, providing no direct light.
On the 203rd Meeting of the American Astronomical Society
in January 2004, information was reported by a team led by A. Witt of the University of Toledo, Ohio
, that his team had discovered the spectral signatures of the polycyclic aromatic hydrocarbons anthracene
and pyrene
in the ultraviolet light emitted by the nebula - potentially vital organic molecules for the formation of life. Until recently, it was thought that the ultraviolet light would quickly destroy these hydrocarbons; the fact that the hydrocarbons still exist today has been explained by recently discovered molecular forces.
A likely explanation for its symmetry is that the central star - actually a close pair of stars - is surrounded by a thick dust torus
which pinches the otherwise spherical outflow into tip-touching cone shapes. Because we view the torus edge-on, the boundary edges of the cone shapes seem to form an X. The distinct rungs suggest the outflow occurs in fits and starts. About 2,300 light-years away toward the constellation Monoceros, the Red Rectangle Nebula should be transformed into a planetary nebula as its cool central star becomes a hot white dwarf over the next few thousand years.
The Hubble Space Telescope
has revealed a wealth of new features in the Red Rectangle that cannot be seen by ground-based telescopes looking through Earth
's turbulent atmosphere
. The origins of many of the features in this dying star
still remain hidden or even outright mysterious. Some are well explained by theorists like the Dutch scientist Vincent Icke from Leiden University
in the Netherlands
.
In 1981 Vincent Icke and collaborators showed that a spherical gas ejection from a dying star
hitting a dust torus would give rise to shocks
that can produce cone-like outflows similar to the two cones seen in this nebula.
Of the many different parameters in Vincent Icke’s calculations, only the density of the gas and the dust are observed in the nebula.
Protoplanetary nebula
A protoplanetary nebula or preplanetary nebula is an astronomical object which is at the short-lived episode during a star's rapid stellar evolution between the late asymptotic giant branch phase and the subsequent planetary nebula phase. A PPN emits strongly in infrared radiation, and is a...
in the Monoceros constellation. Also known as HD 44179, the nebula was discovered in 1973 during a rocket flight associated with the AFCRL Infrared Sky Survey called Hi Star. The binary system
Binary system (astronomy)
A binary system is an astronomical term referring to two objects in space which are so close that their gravitational interaction causes them to orbit about a common center of mass. Some definitions A binary system is an astronomical term referring to two objects in space (usually stars, but also...
at the center of the nebula was first discovered by Robert Grant Aitken
Robert Grant Aitken
Robert Grant Aitken was an American astronomer.He worked at Lick Observatory in California. He systematically studied double stars, measuring their positions and calculating their orbits around one another...
in 1915.
Characteristics
Diffraction-limited speckle images of it in visible and near infrared light reveal a highly symmetric, compact bipolar nebulaBipolar nebula
A bipolar nebula is a distinctive nebular formation characterized by an axially symmetric bi-lobed appearance.Many, but not all, planetary nebulae exhibit an observed bipolar structure...
with X-shaped spikes which imply toroidal dispersion of the circumstellar material. The central binary system is completely obscured, providing no direct light.
On the 203rd Meeting of the American Astronomical Society
American Astronomical Society
The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...
in January 2004, information was reported by a team led by A. Witt of the University of Toledo, Ohio
University of Toledo
The University of Toledo is a public university in Toledo, Ohio, United States. The Carnegie Foundation classified the university as "Doctoral/Research Extensive."-National recognition:...
, that his team had discovered the spectral signatures of the polycyclic aromatic hydrocarbons anthracene
Anthracene
Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three fused benzene rings. It is a component of coal-tar. Anthracene is used in the production of the red dye alizarin and other dyes...
and pyrene
Pyrene
Pyrene is a polycyclic aromatic hydrocarbon consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is . This colourless solid is the smallest peri-fused PAH...
in the ultraviolet light emitted by the nebula - potentially vital organic molecules for the formation of life. Until recently, it was thought that the ultraviolet light would quickly destroy these hydrocarbons; the fact that the hydrocarbons still exist today has been explained by recently discovered molecular forces.
A likely explanation for its symmetry is that the central star - actually a close pair of stars - is surrounded by a thick dust torus
Torus
In geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...
which pinches the otherwise spherical outflow into tip-touching cone shapes. Because we view the torus edge-on, the boundary edges of the cone shapes seem to form an X. The distinct rungs suggest the outflow occurs in fits and starts. About 2,300 light-years away toward the constellation Monoceros, the Red Rectangle Nebula should be transformed into a planetary nebula as its cool central star becomes a hot white dwarf over the next few thousand years.
The Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
has revealed a wealth of new features in the Red Rectangle that cannot be seen by ground-based telescopes looking through Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's turbulent atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
. The origins of many of the features in this dying star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
still remain hidden or even outright mysterious. Some are well explained by theorists like the Dutch scientist Vincent Icke from Leiden University
Leiden University
Leiden University , located in the city of Leiden, is the oldest university in the Netherlands. The university was founded in 1575 by William, Prince of Orange, leader of the Dutch Revolt in the Eighty Years' War. The royal Dutch House of Orange-Nassau and Leiden University still have a close...
in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
.
Asymptotic Giant Branch
The asymptotic giant branch is the region of the Hertzsprung-Russell diagram populated by evolving low to medium-mass stars. This is a period of stellar evolution undertaken by all low to intermediate mass stars late in their lives....
hitting a dust torus would give rise to shocks
Bow shock
A bow shock is the area between a magnetosphere and an ambient medium. For stars, this is typically the boundary between their stellar wind and the interstellar medium....
that can produce cone-like outflows similar to the two cones seen in this nebula.
Of the many different parameters in Vincent Icke’s calculations, only the density of the gas and the dust are observed in the nebula.
See also
- Red Square NebulaRed Square NebulaThe Red Square Nebula is a celestial object located in the area of the sky occupied by star MWC 922 in the constellation Serpens. The first images of this bipolar nebula, taken using the Mt. Palomar Hale telescope in California, were released in April 2007...
- Aromatic hydrocarbons, (AH)
- Polycyclic aromatic hydrocarbonPolycyclic aromatic hydrocarbonPolycyclic aromatic hydrocarbons , also known as poly-aromatic hydrocarbons or polynuclear aromatic hydrocarbons, are potent atmospheric pollutants that consist of fused aromatic rings and do not contain heteroatoms or carry substituents. Naphthalene is the simplest example of a PAH...
, (PAH) - NebulaNebulaA nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
External links
- The remarkable Red Rectangle: A Stairway to Heaven?
- Dying Star Sculpts Rungs of Gas and Dust
- Charged polycyclic aromatic hydrocarbon clusters and the galactic red emission, 2007.
- Astronomy Picture of the DayAstronomy Picture of the DayAstronomy Picture of the Day is a website provided by NASA and Michigan Technological University . According to the website, "Each day a different image or photograph of our universe is featured, along with a brief explanation written by a professional astronomer."The photograph is not necessarily...
- The Red Rectangle Nebula from Hubble (14 June 2010) - The Red Rectangle