R Aquarii and its peculiar nebula
AAO image reference AAT 87.    « Previous || Next »

R Aquarii and its peculiar nebula. R_aquarii.jpg
Top left is NE. Image width is about 5 arc min
Image and text © 1993-2010, Australian Astronomical Observatory, photograph by David Malin.


The star at the centre of this unique nebula has been known to be variable since 1810. It has a period of a little over a year, but the brightness shifts are erratic, ranging from the threshold of naked eye visibility to about 200 times fainter. At the centre of the nebula is a symbiotic star, an interacting pair consisting of a red giant and white dwarf. The dwarf draws in material from the giant, occasionally ejecting the surplus as the strange loops seen in the colour picture. The white dwarf itself is invisible and the light from the red dwarf is truly red, perhaps because the whole system is embedded in very dusty nebula which absorbs what blue light there is. R Aquarii is about 700 light years away. Its J2000 position is RA: 23h 43min 49.5sec DEC: -15 17' 04".

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Updated by David Malin, 2010, August 1