An artist’s impression of HD 189733b and its star (credit: ESA - C. Carreau)

‘Extra-solar’ planets are those outside our Solar System and more than 200 have been discovered orbiting stars close to our own Sun. The planet with water in its atmosphere is known as HD 189733b, and orbits a star in the constellation of Vulpecula the Fox, which is 64 light years from the Sun. HD 189733b is known as a “transiting planet” because it passes directly in front of its star, as viewed from the Earth.

The researchers, led by Dr Giovanna Tinetti of the European Space Agency and UCL’s Department of Physics & Astronomy, found that as HD 189733b passes in front of its ‘sun’, it absorbs starlight in a way that can only be explained by the presence of water vapour in its atmosphere. This is the first time that astronomers have been able to confirm that water is present on an extra-solar planet.

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Artist's impression of the planetary system around the red dwarf Gliese 581. Using the instrument HARPS on the ESO 3.6-m telescope, astronomers have uncovered 3 planets, all of relative low-mass: 5, 8 and 15 Earth masses. The five Earth-mass planet makes a full orbit around the star in 13 days, the other two in 5 and 84 days. (c) ESO

This exoplanet - as astronomers call planets around a star other than the Sun – is the smallest ever found up to now [1] and it completes a full orbit in 13 days. It is 14 times closer to its star than the Earth is from the Sun. However, given that its host star, the red dwarf Gliese 581 [2], is smaller and colder than the Sun – and thus less luminous – the planet nevertheless lies in the habitable zone, the region around a star where water could be liquid!

“We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid,” explains Stéphane Udry, from the Geneva Observatory (Switzerland) and lead-author of the paper reporting the result. “Moreover, its radius should be only 1.5 times the Earth’s radius, and models predict that the planet should be either rocky – like our Earth – or covered with oceans,” he adds.

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The health benefits of cutting down on dietary saturated fatty acids and including higher levels of unsaturated fatty acids are well documented. Nutritional research is focusing on the effects of incorporating these healthier fatty acids, such as conjugated linoleic acid (CLA), into animal and human diets. CLA is present in dairy products and meat from ruminants and in very low amounts in our bodies.

Cows grazing (courtesy of Teagasc)

Health benefits of conjugated linoleic acid (CLA)
Dr Helen Roche, a senior lecturer in molecular nutrition in Trinity College Dublin, has been studying CLA and its biological properties for several years. "CLA seems to protect cells programmed to become diabetic against development of diabetes and it also prevents disease processes that lead to atherosclerosis, chronic inflammation and colon cancer," says Dr Roche.

Classified as a nutraceutical or nutritional supplement, CLA is thought to change the balance between fat cells and muscle cells in the body and is currently on sale in health shops as a supplement to help people improve their body tone.

"The problem is that commercially available supplements contain two forms of the compound known as isomers," explains Dr Paul Evans, a researcher with the Centre for Synthesis and Chemical Biology (CSCB). "Isomers are molecules that have the same molecular formula but the atoms are arranged differently in space. In the case of CLA one isomer known as cis-9-trans-11 CLA has beneficial effects but the other form, trans-10-cis-12 CLA, can be detrimental and could induce a diabetic state."

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