Eww! That's a Dirty Star: Let's Go There!

"Dirty Stars Make Great Hosts for New Worlds"
Space.com (October 7, 2009)

"Dirty stars — those rich in heavier elements — make the best hosts of planetary systems, new research suggests.

" 'When you observe stars, the ones with more heavy elements have more planets,' said Mordecai-Mark Mac Low, Curator of Astrophysics at the American Museum of Natural History and co-author of the study detailing the research in the journal Astrophysical Journal Letters.

"Some stars observed in our galaxy appear to be lonely gas furnaces, radiating their heat out into the surrounding cold emptiness of space, while others shine their light on a skirt of orbiting planets.

"Whether a star has planets or not often depends on its composition: Observations of distant solar systems show that exoplanets, or planets that orbit stars other than the sun, are much more abundant around stars that have a greater abundance of elements heavier than helium, including iron and oxygen. These elements are building blocks for rocks and ice.

" 'In other words, what's in the disk reflects what's in the star. This is a common sense result,' Mac Low said...."

This isn't exactly a new idea - that stars with more elements other than hydrogen and helium in them are more likely to have planets - but this article tells about some new research that backs up the 'common sense' conclusion.

Although I'd be glad to hear that astronomers have found a new world orbiting another star, it would be at least as exciting to learn that they've found an old one - say about 4,000,000,000 or 5,000,000,000 years old, with a surface temperature between the freezing and boiling point of water, that's a little blue and a little red (and the ratios change regularly), and an atmosphere with oxygen in it.

A radio message saying, in English, "ten percent discount for Earthlings" would be great - and a little disturbing. But just finding a damp planet with oxygen in the atmosphere would be a huge event.

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Related posts, at

• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"