A new project called PlanetQuest will soon offer a way to get involved personally with the hunt for extrasolar planets. The idea is to use the power of distributed computing, as the hugely influential SETI@home project has already done, letting people run data analysis software as a screensaver that operates whenever their computer is idle. PlanetQuest will be designed to hunt for planets by studying high-density star regions looking for occlusions -- in other words, for evidence that an extrasolar planet has moved between us and its star. Laurance Doyle, an astrophysicist at the SETI Institute, notes that while occlusions may be rare (after all, the stellar system must be lined up with ours so that planetary orbits cross our line of vision), the hunt will also yield dividends in terms of our knowledge of variable stars, as well as broader issues like stellar stability and evolution. But even as we accumulate new data, we still have the problem of managing what we have. Consider the...

Terrestrial Planet Finder will one day help us detect Earth-like worlds around other stars, no matter which technologies are deployed (Centauri Dreams remains an advocate of Webster Cash's New Worlds Imager). But once we start finding such worlds, what sort of data signatures should we look for to help us identify habitable surface environments? That question has been addressed in a new way by Penn State Erie assistant professor of physics and astronomy Darren M. Williams. Working with the University of Hawaii's Eric Gaidos, Williams outlined a theory that planets with abundant water should show strong scattering of starlight from ocean surfaces and discussed ways of examining such data. From a summary of the presentation: "Here we simulate the specular reflection of starlight off the surface of Earth-like planets to calculate visible light curves for different viewing geometries, obliquities, and land-sea fractions. The amplitude and polarization of the reflected signal is found to...

An extrasolar planet the size of Neptune is news, and when that planet is in an orbit roughly analagous to Neptune's in our own solar system, researchers take special note. After all, almost all the planets we've discovered around other stars are huge gas giants orbiting extremely close to their parent stars. And this extrasolar planet is more anomalous still. It was back in May that a team from the University of Rochester led by Drs. Dan Watson and William Forrest, using NASA's Spitzer Space Telescope, discovered a gap in the dust around the star CoKu Tau 4, one of five young stars they surveyed in the constellation Taurus. The central part of the dust disk around the star was missing, a 'hole' that can only be explained by the presence of a planet, and a young one, at that. In fact, this planet is assumed to be between 100,000 to half a million years old, a toddler by any astronomer's definition. CoKu Tau 4 is itself about one million years old; by contrast, Earth is approximately...

An interesting article in the 30 October New Scientist discusses a new theory on how the solar system began. A team from the Arizona State University led by astronomer Jeff Hester argued last May in Science that isotopic evidence and accumulated astronomical observations argue for a violent, energetic region near high-mass stars as the birthplace of our system. Image: The Eagle Nebula, as photographed by the Hubble Space Telescope. This famous photo, often known as "The Pillars of Creation," shows giant nebular clouds being evaporated by the ferocious energy of massive stars, exposing emerging solar systems, much like our own. Credit: NASA/HST/Jeff Hester and Paul Scowen Forming near a massive, unstable star would have had interesting implications for the appearance of habitable planets. From an ASU press release: The process leaves a Sun-like star and its surrounding disk sitting in the interior of a low density cavity with a massive star close at hand. Massive stars die young,...

Astronomers from Japan's Ibaraki University, the Japan Aerospace Exploration Agency, the University of Tokyo, and the National Astronomical Observatory of Japan have analyzed the dust disk surrounding the star Beta Pictoris, with intriguing results. Using an instrument called the Cooled Mid-Infrared Camera and Spectrometer (COMICS) and the Subaru telescope, the team found that ring-like distributions of planetesimals (something like the asteroid belt in our own Solar System) occur at three locations, measured as 6, 16 and 30 AU from the star. An unseen planet some 12 AU from the star may be what is keeping these belts intact. The disk around Beta Pictoris, a young star whose disk is more or less edge-on to our solar system, has been studied for some twenty years. Working in the infrared, Yoshiko K. Okamoto of Ibaraki University in Japan and his colleagues have provided new details of its structure. Image: Depiction of a possible planet (upper left) flanked by bands of dust within the...