Even real stars wear bling

Using the Anglo-Australian Telescope in northwest NSW, astronomers have found a star glittering with zirconium, the material used to make diamond look-alikes.

They calculate the star contains four billion tonnes of zirconium, or 4,000 times the world's annual production.

The astronomers, from Armagh Observatory in Northern Ireland, are publishing their results in the journal Monthly Notices of the Royal Astronomical Society.

The star in question is LS IV-14 116, 2,000 light years from the Sun in the direction of the border between the constellations of Capricorn and Aquarius.

The research team, led by graduate student Naslim Neelanamkodan and her supervisor, Dr Simon Jeffrey, were studying this and other stars known as helium-rich hot subdwarfs.

"These stars are all freaks," said Dr Simon O?Toole of the Australian Astronomical Observatory in Sydney, an expert on hot subdwarfs.

The zirconium would be concentrated in the outer layers of the star, he said.

"In these hot subdwarfs the metals actually float to the surface of the star, pushed out by radiation pressure," Dr O?Toole explained.

"You can get nickel-crusted stars, lead-crusted stars, tin-crusted stars."

But LS IV-14 116 was the first one he?d heard of with an outer layer of zirconium, he said.

Most stars like the Sun have about ten zirconium atoms for every million silicon atoms. LS IV-14 116 has two million zirconium atoms for every one million silicon atoms.

The Australian Astronomical Observatory, Australia?s national optical observatory, operates the Anglo-Australian Telescope and the UK Schmidt Telescope at Siding Spring Observatory in New South Wales, Australia. It is part of the Commonwealth Department of Innovation, Industry, Science and Research.

More information

Media assistance: Helen Sim 
T: +61 2 9372 4251
M: +61 419 635 905

Dr Simon O'Toole, Australian Astronomical Observatory (Sydney, Australia)
Tel: 02 9372 4856
Mob: 043 491 6378

Dr Simon Jeffery, Armagh Observatory (Northern Ireland)
Tel: +44 (0)28 3751 2958
Mob: +44 (0)78 4515 1764

Ms Naslim Neelanamkodan, Armagh Observatory (Northern Ireland)
Tel: +44 (0)28 3751 2965
Mob: +44 (0)78 9570 6450


An extremely peculiar hot subdwarf with a ten-thousand fold excess of zirconium, yttrium and strontium', Naslim N. et al, Monthly Notices of the Royal Astronomical Society, in press. A preprint of the paper can be seen at http://arxiv.org/abs/1010.5146 .


Artist?s impressions of LS IV -14 116 can be downloaded from http://star.arm.ac.uk/press/2010/Zirconium.html

1. An artist's impression of LS IV-14 116. The white clouds are rich in zirconium and lie above the blue surface of the star. Image: Natalie Behara

2. An artist's impression of part of LS IV-14 116. The white clouds are rich in zirconium and lie above the blue surface of the star. Image: Natalie Behara