ESO Releases New Images Of R Coronae Australis

June 30, 2010




The intense radiation given off by these hot young stars interacts with the gas surrounding them and is either reflected or re-emitted at a different wavelength. These complex processes, determined by the physics of the interstellar medium and the properties of the stars, are responsible for the magnificent colors of nebulae. The light blue nebulosity seen in this picture is mostly due to the reflection of starlight off small dust particles. The young stars in the R Coronae Australis complex are similar in mass to the Sun and do not emit enough ultraviolet light to ionize a substantial fraction of the surrounding hydrogen. This means that the cloud does not glow with the characteristic red color seen in many star-forming regions.

The huge dust cloud in which the reflection nebula is embedded is here shown in impressively fine detail. The subtle colors and varied textures of the dust clouds make this image resemble an impressionist painting. A prominent dark lane crosses the image from the center to the bottom left. Here the visible light emitted by the stars that are forming inside the cloud is completely absorbed by the dust. These objects could only be detected by observing at longer wavelengths, by using a camera that can detect infrared radiation.

R Coronae Australis itself is not visible to the unaided eye, but the tiny, tiara-shaped constellation in which it lies is easily spotted from dark sites due to its proximity on the sky to the larger constellation of Sagittarius and the rich star clouds towards the center of our own galaxy, the Milky Way.

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Image 2: This spectacular wide field image shows the area around the star R Coronae Australis. A huge dust cloud, about eight light-years across, dominates the center of the image. The bluish reflection nebula close to R Coronae Australis is right of center and the globular cluster NGC 6723 lies to the upper-right of the nebula. Corona Australis is a tiny tiara-shaped constellation, located next to the larger constellation of Sagittarius, in the direction of the center of the Milky Way. In spite of its faintness, this southern winter constellation can be easily spotted from dark sites because of its characteristic shape and position in the sky. Credit: Loke Kun Tan (StarryScapes.com)

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ESO Releases New Images Of R Coronae Australis

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