Alpha Centauri ‘should have an Earth-like planet’

Tomas Martin @ 11-03-2008

An artist’s impression of an earth-like planet around Alpha CentauriAlpha Centauri is the closest star system to our own but with a bonus: there are three stars rather than one. It’s also one of the best chances we know in the local area to have a planet similar to Earth capable of developing life like ours.

If any planet were to harbour earth-like life in the three-star system, it would likely be around Alpha Centauri A, which is most similar to the sun. However astronomer Javier Guedes and his coauthors believe that Alpha Centauri B is likely to have terrestrial planets in its habitable region. Based on computer simulations of planet formation, Guedes and his team found that no matter what starting conditions, a terrestrial planet always formed around the star. By studying the ‘wobbles’ the planet causes on its parent star, the team reckon they could find any potential planets within a few years.

[story via Daily Galaxy, image via Solstation]


Detecting vegetation, analyzing atmospheres on extrasolar planets

Edward Willett @ 05-12-2007

sodiumlinesWe know there are lots of planets orbiting other stars: we’ve found more than 250 of them already, and we’re getting better at finding them all the time. But the big question is, do any of the obviously plentiful extrasolar planets in the galaxy support life?

So far, we can’t tell: but we’re getting closer to being able to. Dr. Luc Arnold of the CNRS Observatoire de Haute-Provence in France thinks we might be able to tell if an extrasolar planet supports vegetation via a spectral analysis of the light reflected off it, because vegetation absorbs a lot of light around a specific wavelength for use in photosynthesis (on Earth, that’s red light, so this phenomenon is called the Vegetation Red Edge).

We don’t have any Earth or space-based telescopes that are able to carry out spectral analysis fine-grained enough to do this, yet, and even ESA’s Darwin and NASA’s Terrestrial Planet Finder, launching within the next decade or so, won’t be able to–but the next generation of planet-finding spacecraft after that probably will be.

One thing we have managed to do, though, is analyze the atmosphere of an extrasolar planet: a "hot Jupiter" orbiting a star in the constellation Vulpecula. By measuring which wavelengths of light from the planet’s star are absorbed by its atmosphere every time it swings between the star and Earth, University of Texas at Austin astronomer Seth Redfield determined the planet’s atmosphere contains sodium. (Via Universe Today and Universe Today.)

Again, we’re a long way from using the same technique to look for oxygen–a strong indicator of Life As We Know It–in Earth-sized planets’ atmospheres. But it’s likely just a matter of time. (Illustration: S. Redfield/T. Jones/McDonald Observatory.)

#

A Personal Note: I apologize for a lack of posts from me over the past little while. As Paul mentioned in his last Friday Free Fiction post, I’m currently in rehearsal for a professional production of Beauty and the Beast, and it’s taking up most of my time. I hope to still manage an occasional post, though, until the show ends December 30, and resume regular posting in the new year.

[tags]astronomy, extrasolar planets, extraterrestrial life[/tags]