Topic: Tau Ceti too rocky for life?

[Nemesis]

Link to article

The star, Tau Ceti, lies just 12 light-years away and has been eyed as a possible oasis for life because of its similarity to the Sun and the inference of a surrounding debris disk that may harbour planets.

Imaging the disk has now identified the 10-billion-year-old Tau Ceti as the oldest of about a dozen stars with confirmed disks. Its span is similar to our Solar System's Kuiper Belt.

This shadowy belt consists of a ring of comets and asteroids reaching just past Pluto's orbit. But the amount of dust around Tau Ceti suggests it is circled by more than 10 times as many of the objects.

"It is likely that with so many large impacts life would not have the opportunity to evolve," says Greaves, whose team imaged Tau Ceti for the first time.

But other astronomers say the implications for life are not so clear. "You could argue the other way as well," says Glenn Schneider of the University of Arizona in Tucson, US. He says the key factor is whether the impacts would occur in the habitable zone - the region around the star where liquid water can exist.

Scott Kenyon, an astronomer at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, US, agrees. He says a giant planet could orbit the star, gravitationally deflecting comets and asteroids away from planets that may support life in the same way that Jupiter protects Earth.

But, says Kenyon, "it's a really exciting observation to see the dust around that old a star". Stars are born in a swirl of gas and dust, which in less than a million years is thought to coalesce into larger objects such as comets. These collide over time, producing more dust, but the star's radiation blows it away, eroding the disk.

For a star like Tau Ceti to have a dust disk at its advanced age, "you need to have something that keeps making and stirring the dust", Kenyon told New Scientist.

[J. Carney]

Sounds to me like they are starting to worry about the other houses in the neighborhood... about time.

I'm no expert, but if we have this feature in our system, and then Tau Ceti has it too, it is still an encouraging find dispite the fact that there are a lot more rocks.

[Age]

  What about Bernard Star or Epsilon Erdani?I kind a like those two I know they are in our stellar nieghbourhood.

[Stormbringer]

  What about Bernard Star or Epsilon Erdani?I kind a like those two I know they are in our stellar nieghbourhood.

Epsilon eridani is a good cadidate. Don't know about barnard's star but the centauri trinary star system has one star candiate as well. the other two alpha proxima and alpha centauri arenot good candidates.

[Stormbringer]

*THIS* is ceti alpha five! Ceti alpha six blew up weeks after we got here! ...Admiral Kirk never bothered to check up on us.