Red Rectangle Nebula

Protoplanetary nebula


caption =
name = Red Rectangle Nebula
epoch = J2000
ra = RA|06|19|58.2160Harv|SIMBAD|2007]
dec = DEC|-10|38|14.691
dist_ly = 2.3 ± 0.3 kly (710 ± 100 pc)Harv|Men'shchikov|Schertl|Tuthill|Weigelt|2002]
appmag_v = 9.02
size_v =
constellation = Monoceros
radius_ly =
absmag_v =
notes =
names = HD 44179,
RAFGL 915

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.

Characteristics

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

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. 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 [http://space.com/scienceastronomy/070406_red_rectangle.html molecular forces] .

So why does it look like an 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 modeling 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, although in astrophysics magnetic fields are also significant, so the math used is magnetohydrodynamics.

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. In Astronomy, the shape of an object's clouds is referred to as its morphology.

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 Nebula
* Aromatic hydrocarbons, (AH)
* Polycyclic aromatic hydrocarbon, (PAH)
* Nebula

External links

* [http://www.esa.int/esaCP/SEMHBNGHZTD_FeatureWeek_0.html The remarkable Red Rectangle: A Stairway to Heaven?]
* [http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/11/ Dying Star Sculpts Rungs of Gas and Dust]
* [http://spacescience.arc.nasa.gov/redglow/ Charged polycyclic aromatic hydrocarbon clusters and the galactic red emission] , 2007.

Notes

References

* Harvard reference
Surname1 = Cohen
Given1 = M.
Surname2 = Anderson
Given2 = C. M.
Surname3 = Cowley
Given3 = A.
Surname4 = Coyne
Given4 = G. V.
Surname5 = Fawley
Given5 = W.
Surname6 = Gull
Given6 = T. R.
Surname7 = Harlan
Given7 = E. A.
Surname8 = Herbig
Given8 = G. H.
Surname9 = Holden
Given9 = F.
Surname10 = Hudson
Given10 = H. S.
Surname11 = Jakoubek
Given11 = R. O.
Surname12 = Johnson
Given12 = H. M.
Surname13 = Merrill
Given13 = K. M.
Surname14 = Schiffer
Given14 = F. H.
Surname15 = Soifer
Given15 = B. T.
Surname16 = Zuckerman
Given16 = B.
Title = The peculiar object HD 44179 'The red rectangle'
Journal = Astrophysical Journal
Year = 1975
Date = February 15 1975
Volume = 196
Issue = 1
Pages = 179-189
URL = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975ApJ...196..179C
* Harvard reference
Surname1 = American Astronomical Society
Title = Meeting program contents (Retrieved January 2, 2006)
Year = 2004
URL = http://www.aas.org/meetings/aas203/
* Harvard reference
Surname1 = Battersby
Given1 = Stephen
Title = Space molecules point to organic origins (Retrieved January 2, 2006)
Journal = New Scientist
Year = 2004
URL = http://www.newscientist.com/news/news.jsp?id=ns99994552
* Harvard reference
Surname1 = SIMBAD
Title = Results for Red Rectangle
Authorlink = SIMBAD
Journal =
Year = 2007
Date = January 7 2007
Publisher = SIMBAD, Centre de Données Astronomiques de Strasbourg
URL = http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=Red+Rectangle
* Harvard reference
Surname1 = Men'shchikov
Given1 = A. B.
Surname2 = Schertl
Given2 = D.
Surname3 = Tuthill
Given3 = P. G.
Surname4 = Weigelt
Given4 = G.
Surname5 = Yungelson
Given5 = L. R.
Title = Properties of the close binary and circumbinary torus of the Red Rectangle
Journal = Astronomy and Astrophysics
Year = 2002
Volume = 393
Pages = 867-885
URL = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002A%26A...393..867M