Stars and Nebulae in the Southern Crown

Stars and Nebulae in the Southern Crown
From The European Southern Observatory
This color image of the R Coronae Australis region in the southern Milky Way was obtained with the Wide Field Imager at the 2.2-m MPG/ESO Telescope on La Silla (Chile). It is based on a series of CCD exposures through optical B-, V- and R-filters, here rendered as blue, green and red, respectively. The sky field shown measures approx. 33.7 arcmin x 31.9 arcmin (about the diameter of the full moon).  The R Coronae Australis complex of young stars and interstellar gas clouds is one of the nearest star-forming regions, at a distance of about 500 light-years from the Sun. It is seen in the southern constellation of that name (The "Southern Crown"). The field shown measures about 4.7 light-years x 4.7 light-years. It displays the central part of the complex, its brightest stars, and the nebulosity that they illuminate. The interstellar clouds that are associated with the complex are visible all across this field and also beyond its borders  due to the obscuring effect of the dust particles that "dim" the light of stars behind these clouds. This effect is particularly noticeable in the lower left corner where very few stars are seen.
R Coronae Australis, the bright star from which the entire complex is named, is located at the center of the field and illuminates the reddish nebula around it. The bright star in the lower part, illuminating a somewhat bluer nebula, is TY Coronae Australis. These two stars and several others in this field are T Tauri stars, a type that is quite common in star-forming regions. They are in the early stages of stellar evolution and display various observable characteristics of this phase, e.g. emission at visible and infrared wavelengths due to the accretion of matter left over from their formation, as well as X-ray emission.  The nebulosity seen in this picture is mostly due to reflection of the stellar light by small dust particles. The stars in the R Coronae Australis complex do not emit sufficient ultraviolet light to ionize a substantial fraction of the surrounding hydrogen, and thereby cause this gas to glow.
Based on press release with ESO PR Photo 25a/00
Catalog #:  Photo 25a/00
Target Name: Stars and Nebulae in the Southern Crown

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 Last modified on Sunday, December 17, 2000