Nebulae

NGC6726 and HH 100 in Corona Australis

The Corona Australis Molecular Complex

The small Southern constellation of Corona Australis (the Southern Crown) hosts an impressive display of dust clouds and reflection nebulae centered around the star R Coronae Australis. This area is known as the Corona Australis Molecular Complex and at a distance of 430 light years it is one of the closest star-forming regions to us.

The image here frames the most colourful part of the complex, dominated by two large blue reflection nebulae. The brightest of the two is NGC6726-7 in the upper half of the field, which is illuminated by two separate young blue stars HD176386 and TY CrA. In the lower half reflection nebula IC4812 is lit by a brilliant close pair of stars; HD176269 and HD176270.

To the lower left of NGC6726-7 lies the most intricate and colourful part of the complex, surrounding R Corona Australis itself. Here several bright arcs, loops and intriguing structures can be seen. These are shaped by violent outbursts from young protostars still embedded in the nebula. Also visible are many small bright red Herbig-Haro objects; the result of plasma jets ejected from young protostars which collide with the surrounding gas and dust and cause the glowing emission.

The condensation of dark molecular clouds around R Coronae Australis makes the star heavily obscured from our view. The star itself is a very young B5 type, still migrating towards the main sequence on the H-R diagram. It is some 2 to 10 times heavier than our Sun and about 40 times more luminous. In the lower right of the image a few distant galaxies appear, heavily reddened by the obscuring dust.

Image details:
Date: 10^th 22^nd July and 10^th 12^th 17^th August 2015
Exposure: LRGB: 660:105:100:95 mins, total 16 hours @ -30C
Telescope: Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand

CoronaLRGB16Hours3326x2504