Red Rectangle Nebula

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**Red Rectangle Nebula**
Observation data (Epoch J2000)
Protoplanetary nebula	Lists of nebulae
PIA 04533
Right ascension	06^h 19^m 58.2160^s^[1]
Declination	-10° 38′ 14.691″^[1]
Distance	2.3 ± 0.3 kly (710 ± 100 pc)^[2]
Apparent magnitude (V)	9.02^[1]
Apparent dimensions (V)
Constellation	Monoceros
Physical characteristics
Radius
Absolute magnitude (V)
Notable features
Other designations	HD 44179,^[1] RAFGL 915^[1]

The Red Rectangle Nebula, so called because of its unique shape and color, is a protoplanetary nebula near 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.

1 Characteristics
2 See also
3 External links
4 Notes
5 References

[edit] Characteristics

Diffraction-limited speckle images of it in visible and near infrared light reveal a highly symmetric, compact bipolar nebula with × shaped spikes which imply toroidal dispersion of the circumstellar material. The central binary system is completely obscured, providing no direct light.(Men'shchikov et al. 2002)

Proto-Planetary Nebula

Exciting information was reported at the 203^rd Meeting of the American Astronomical Society in January 2004 by a team led by A. Witt of the University of Toledo, Ohio, who 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.

So why does it look like a big X? A likely explanation 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 fanciful constellation Monoceros, the Red Rectangle nebula should be transformed into a glorious 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.

Meteorologists produce weather forecasts by advanced calculations of temperatures, pressures, velocities and densities for the air masses in our atmosphere and, to some degree, theorists like Icke are doing exactly the same for objects in space. Whether modelling the weather in the Earth’s atmosphere or the processes in distant gaseous nebulae, scientists calculate the motion of the gas by using a complicated set of expressions known as hydrodynamic equations.

Most of the matter in the Universe is in the form of gas. The weather on Earth gives rise to spectacular patterns such as thunderclouds and tornadoes in the air masses here. Likewise, the ‘weather’ in gas clouds in space, like the Red Rectangle, can be fascinating.

Of the many different parameters in Vincent Icke’s calculations, only the density of the gas and the dust are observed in the nebula.