Super planetary nebula
DR EMILY BALDWIN
Posted: August 14, 2009
A team of astronomers from Australia and the United States have discovered a new class of object which they have nicknamed 'Super Planetary Nebula'.
Planetary nebula are created from the shells of gas and dust thrown off by a dying star in the last stages of its life. They are commonly seen around stars that are up to the same size as our own Sun.An optical image from the 0.6-m University of Michigan/CTIO Curtis Schmidt telescope of the brightest radio planetary nebula in the Small Magellanic Cloud, JD 04. The inset box shows a portion of this image overlaid with radio contours from the Australia Telescope Compact Array. Optical images courtesy of the Magellanic Cloud Emission Line Survey (MCELS) team.
In a new survey, led by Miroslav Filipovic from the University of Western Sydney, a team of astronomers studied the Magellanic Clouds, two neighbouring galaxies of the Milky Way. Using the radio telescopes of the Australian Telescope National Facility, they discovered that 15 strong radio sources married up with well known planetary nebula identified in optical telescopes.
The unusually strong radio signal suggests that this new population may be the long predicted class of nebula expected around stars between one and eight times the mass of our Sun. Until now, the majority of known planetary nebula have masses of just 0.3 times the mass of the Sun, surrounding stars no more massive then 0.6 Suns. The new so-called Super Planetary Nebula have expelled material equivalent to 2.6 solar masses.Planetary nebula, the shells of gas and dust thrown off in the final death throes of a star, come in all shapes and sizes. From left to right: the Cat's Eye Nebula (X-ray: NASA/UIUC/Y.Chu et al; Optical: NASA/HST); the Eskimo Nebula (NASA, ESA, Andrew Fruchter (STScI), and the ERO team (STScI + ST-ECF)) and the Ring Nebula (NASA and The Hubble Heritage Team (STScI/AURA)).
"This came as a shock to us as no one expected to detect these objects at radio wavelengths and with the present generation of radio telescopes," says Filipovic. "We have been holding up our findings for some three years until we were 100 percent sure that they are indeed planetary nebulae".
A handful of the new super planetary nebulae are also three times brighter than those found elsewhere in the Milky Way. Follow up observations are expected from the forthcoming giant radio telescope array planned for the deserts of Western Australia – the Square Kilometre Array.
The Universe under one roof. European AstroFest returns to London on February 7 & 8, 2014. The UK's favourite astronomy conference and exhibition. Visit the official website site for more details.
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