![]() This image was taken at the suggestion of Don Goldman. A large dithering was used in order to try to grab as much detail as possible of the “ladder-like” features. Halpha images did not add any valuable information, just like the Luminance images. The Red rectangle nebula (IRAS 06176-1036, binary system designated HD 44179) is a protoplanetary nebula in the constellation of Monoceros, the unicorn. Several trials about the right exposure time ended up in taking 200 second RGB images. The capture of this object was not a straight forward process. The image below shows the explanation of the unusual “rectangular looking” features of this nebula. This produces the effect of “ladder rungs” that, being circles seen edge on, creates the illusion of seeing a straight “rung”. In the proposed shaping process, one among several processes through which a companion can shape the circumbinary gas, the companion accretes mass from the slow wind blown by the evolved mass losing star. The flow of mass is not constant and happens in irregular periods of about a few hundred years. The bright biconical structure of the Red Rectangle nebula can be understood to be composed of a multiple double-ring system. The mechanism for this formation involves the creation of a torus (doughnut-shaped) of gas around the star, that is seen edge on as well as a pair of “wine glass-shaped” cups, along which matter is flowing from the parent star. Actually, being this the precursor stage for a planetary nebula, it is called a “proto-planetary” nebula. This star will end up the same way, but meanwhile, the combined effect of expanding its shells and the presence of the companion star, is forming this weird structure. The Red Rectangle: molecular emission (contours, observations performed by our astronomers) and optical image (obtained by the HST, courtesy of NASA). This is a stage, that the solitary stars undergo by slowly producing a planetary nebula. ![]() The binary star system conforming HD 44179 involves a Sun-like star that is running out of its primary fuel and expanding its outer shells enough for the second star (orbiting the primary one every 319 days) to start to gravitationally pull some of its mass. Initially, when this nebula was discovered in 1973, its structure was much of a mystery. ![]() At least another such nebula is known, the Red Square Nebula, around the star MWC 922, in the constellation Serpens. The Red Rectangle Nebula is a very peculiar (but not unique) structure around a binary system catalogued as HD 44179 in the constellation Monoceros. Synthetic scattered light intensity maps were generated in order to compare them with images of the Red Rectangle proto-planetary nebula (PPN), which contains the binary system HD 44179. The nebula is shown here in great detail as recently reprocessed image from Hubble Space Telescope. In the visual band of spectrum CW Leo is a tiny star of 19th. The Red Rectangle nebula lies about 2,300 light years away towards the constellation of the Unicorn ( Monoceros ). From our observations and preliminary modeling of the data, we confirm the previously known properties of the disk and obtain a first description of the structure, dynamics, and physical conditions of the outflow.Click on the image for a full resolution version Two objects which might be interesting for CCD observers are CW Leo and the Red Rectangle. Together with an equatorial disk in rotation, we find a low-velocity outflow that more or less occupies the region situated between the disk and the optical X-shaped nebula. It consists of the equatorial rotating disk plus a spectacular axisymmetric nebula seen in the visible, surrounding a double stellar system (Menshchikov et al. Results: These observations provide an unprecedented description of the complex structure of this source. Methods: We obtained high-quality ALMA observations of 12CO and 13CO J = 3-2 and 12CO J = 6-5 line emission in the Red Rectangle, the only post-AGB/protoplanetary object for which a disk in rotation has been mapped. So far, both disks and outflows have not been observed simultaneously. Aims: We aim to study equatorial disks in rotation and axial outflows in post-AGB objects so as to disclose the formation and shaping mechanisms in planetary nebulae.
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