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The Stars That Shouldn’t Exist

first_imgTheories in astronomy are fun to model on paper with equations, but once in awhile they need to stand up to observations.  Phil Berardelli wrote for Science Now:It seems as though every time astronomers point their telescopes at the night sky, some weird new finding forces them to revamp their theories.  And so it is with nine newly discovered white dwarfs.  The stars defy their expected chemical makeup and by rights shouldn’t even exist.  An explanation could open up a new branch of astronomy.The stars may be violating human rights but apparently abide by stellar rights.  One astronomer concluded, “It tells us that nature has found a way that we didn’t know to make white dwarf stars without the usual hydrogen or helium surface layers.”    According to stellar evolution theory, white dwarfs should be enveloped with hydrogen and helium, not carbon.  Astronomers could find no trace of hydrogen or helium in the spectra from these oddball stars.  “Astronomers don’t have a clue why,” the article continued.  Another astronomer commented, “There is currently no explanation how such stars can be formed.  It’s a real challenge to stellar-evolution theory.”  The stars were identified in the Sloan Digital Sky Survey.  See also EurekAlert.  The original paper was published in Nature.1  “Our analysis shows that the atmospheric parameters found for these stars do not fit satisfactorily in any of the currently known theories of post-asymptotic giant branch evolution,” the abstract states.1.  P. Dufour, J. Liebert, G. Fontaine and N. Behara, “White dwarf stars with carbon atmospheres,” Nature 450, 522-524 (22 November 2007) | doi:10.1038/nature06318.This portion of the news is brought to you by the makers of Humble Pie, reminding you that moderation in science is a good thing.    “Twinkle twinkle little star, I don’t wonder what you are; for by spectroscopic ken, I know that you are hydrogen.”  So astronomers used to say.  Always be wary when a scientist says, “I know.”  What rhymes with carbon?    If they had only found seven of these unexpected stars, we could have spun some fairy tales about Snow White Theories and the Seven Dwarfs getting lost in the Data Mine.  We’ll show moderation, though, and not discuss which astronomers were sleepy, dopey or grumpy.(Visited 25 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more

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Irish firm starts SA wind, solar build

first_img13 November 2012 Ireland’s Mainstream Renewable Power announced this week that it was starting construction on solar and wind power projects in South Africa, in a €500-million (about R5.5-billion) investment under a government programme that has ushered in the country’s first large-scale renewable energy projects. The Dublin-based company is one of 28 independent power producers that signed contracts with the South African government last week, in the first round of a programme that will see an initial 1 400 megawatts of renewable energy being added to South Africa’s energy mix, while bringing an estimated R47-billion in new investment into the country. Mainstream Renewable Power and its partners will build a 138 MW wind farm in Jeffreys Bay in the Eastern Cape, and two 50 MW solar photovoltaic (PV) parks in the Northern Cape – one near De Aar and one at Droogfontein near Kimberley. All three projects are scheduled to be fully operational by mid-2014. “The South African government has shown tremendous vision and foresight in creating this new and sustainable industry for South Africa, firmly placing it on the world map for renewable energy generation,” Mainstream CEO Eddie O’Connor said in a statement on Monday. “Mainstream is fully committed to playing a leading role in the delivery of this vision, to bringing significant socio-economic benefits to the areas in which we’re building the projects, as well as clean, free-fuel energy to South Africa.” According to Mainstream, the projects are expected to generate hundreds of jobs during construction and, once operational, the project revenues are expected to benefit local communities through socio-economic and enterprise development. “The projects are expected to produce 635 GWh of electricity, enough to supply up to 48 000 households and displace approximately 628 000 tons of carbon emissions per year,” the company said. Mainstream won the contract for the three projects as the lead partner in a consortium including US power company Globeleq as the strategic equity partner, Thebe Investment Corporation, local engineering firms Enzani Technologies and Usizo Engineering, as well as local community trusts. The projects are being co-developed with Mainstream’s South African partner, renewable energy developer Genesis Eco-Energy. Old Mutual’s IDEAS Managed Fund is an additional consortium member of the Jeffreys Bay Wind Farm. SAinfo reporterlast_img read more