page_title: Corona Australis
section_title: Deep sky objects
hierarchical_section_title: Corona Australis / Features / Deep sky objects
caption_attribution_description: English: Information from ESO: "This magnificent view of the region around the star R Coronae Australis was created from images taken with the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile. R Coronae Australis lies at the heart of a nearby star-forming region and is surrounded by a delicate bluish reflection nebula embedded in a huge dust cloud. The image reveals surprising new details in this dramatic area of sky. "The star R Coronae Australis lies in one of the nearest and most spectacular star-forming regions. This portrait was taken by the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The image is a combination of twelve separate pictures taken through red, green and blue filters. "This image shows a section of sky that spans roughly the width of the full Moon. This is equivalent to about four light-years at the distance of the nebula, which is located some 420 light-years away in the small constellation of Corona Australis (the Southern Crown). The complex is named after the star R Coronae Australis, which lies at the centre of the image. It is one of several stars in this region that belong to the class of very young stars that vary in brightness and are still surrounded by the clouds of gas and dust from which they formed. "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 colours 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 ionise a substantial fraction of the surrounding hydrogen. This means that the cloud does not glow with the characteristic red colour 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 colours and varied textures of the dust clouds make this image resemble an impressionist painting. A prominent dark lane crosses the image from the centre 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 centre of our own galaxy, the Milky Way."
context_page_description: Corona Australis is a constellation in the Southern Celestial Hemisphere. Its Latin name means "southern crown", and it is the southern counterpart of Corona Borealis, the northern crown. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. The Ancient Greeks saw Corona Australis as a wreath rather than a crown and associated it with Sagittarius or Centaurus. Other cultures have likened the pattern to a turtle, ostrich nest, a tent, or even a hut belonging to a rock hyrax.
  Although fainter than its northern counterpart, the oval- or horseshoe-shaped pattern of its brighter stars renders it distinctive. Alpha and Beta Coronae Australis are the two brightest stars with an apparent magnitude of around 4.1. Epsilon Coronae Australis is the brightest example of a W Ursae Majoris variable in the southern sky. Lying alongside the Milky Way, Corona Australis contains one of the closest star-forming regions to the Solar System—a dusty dark nebula known as the Corona Australis Molecular Cloud, lying about 430 light years away. Within it are stars at the earliest stages of their lifespan.
context_section_description: In the north of the constellation is the Corona Australis Molecular Cloud, a dark molecular cloud with many embedded reflection nebulae, including NGC 6729, NGC 6726–7, and IC 4812. A star-forming region of around 7000 M☉, it contains Herbig–Haro objects (protostars) and some very young stars. About 430 light years (130 parsecs) away, it is one of the closest star-forming regions to the Solar System. The related NGC 6726 and 6727, along with unrelated NGC 6729, were first recorded by Johann Friedrich Julius Schmidt in 1865. The Coronet cluster, about 554 light years (170 parsecs) away at the edge of the Gould Belt, is also used in studying star and protoplanetary disk formation.
  R Coronae Australis is an irregular variable star ranging from magnitudes 9.7 to 13.9. Blue-white, it is of spectral type B5IIIpe. A very young star, it is still accumulating interstellar material. It is obscured by, and illuminates, the surrounding nebula, NGC 6729, which brightens and darkens with it. The nebula is often compared to a comet for its appearance in a telescope, as its length is five times its width. S Coronae Australis is a G-class dwarf in the same field as R and is a T Tauri star. Nearby, another young variable star, TY Coronae Australis, illuminates another nebula: reflection nebula NGC 6726–7. TY Coronae Australis ranges irregularly between magnitudes 8.7 and 12.4, and the brightness of the nebula varies with it. Blue-white, it is of spectral type B8e. The largest young stars in the region, R, S, T, TY and VV Coronae Australis, are all ejecting jets of material which cause surrounding dust and gas to coalesce and form Herbig–Haro objects, many of which have been identified nearby. Lying adjacent to the nebulosity is the globular cluster known as NGC 6723, which is actually in the neighbouring constellation of Sagittarius and is much much further away.
  Near Epsilon and Gamma Coronae Australis is Bernes 157, a dark nebula and star forming region. It is a large nebula, 55 by 18 arcminutes, that possesses several stars around magnitude 13. These stars have been dimmed by up to 8 magnitudes by its dust clouds.
  IC 1297 is a planetary nebula of apparent magnitude 10.7, which appears as a green-hued roundish object in higher-powered amateur instruments. The nebula surrounds the variable star RU Coronae Australis, which has an average apparent magnitude of 12.9 and is a WC class Wolf–Rayet star. IC 1297 is small, at only 7 arcseconds in diameter; it has been described as "a square with rounded edges" in the eyepiece, elongated in the north-south direction. Descriptions of its color encompass blue, blue-tinged green, and green-tinged blue.
  Corona Australis' location near the Milky Way means that galaxies are uncommonly seen. NGC 6768 is a magnitude 11.2 object 35′ south of IC 1297. It is made up of two galaxies merging, one of which is an elongated elliptical galaxy of classification E4 and the other a lenticular galaxy of classification S0. IC 4808 is a galaxy of apparent magnitude 12.9 located on the border of Corona Australis with the neighbouring constellation of Telescopium and 3.9 degrees west-southwest of Beta Sagittarii. However, amateur telescopes will only show a suggestion of its spiral structure. It is 1.9 arcminutes by 0.8 arcminutes. The central area of the galaxy does appear brighter in an amateur instrument, which shows it to be tilted northeast-southwest.
  Southeast of Theta and southwest of Eta lies the open cluster ESO 281-SC24, which is composed of the yellow 9th magnitude star GSC 7914 178 1 and five 10th to 11th magnitude stars. Halfway between Theta Coronae Australis and Theta Scorpii is the dense globular cluster NGC 6541. Described as between magnitude 6.3 and magnitude 6.6, it is visible in binoculars and small telescopes. Around 22000 light years away, it is around 100 light years in diameter. It is estimated to be around 14 billion years old. NGC 6541 appears 13.1 arcminutes in diameter and is somewhat resolvable in large amateur instruments; a 12-inch telescope reveals approximately 100 stars but the core rem
caption: The R Coronae Australis region imaged with the Wide Field Imager at ESO's La Silla Observatory. According to ESO, "The light blue nebulosity seen in this picture is mostly due to the reflection of starlight off small dust particles." "A prominent dark lane crosses the image from the centre 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."
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