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...

A new sky survey may reveal further evidence of massive 'super Jupiters' orbiting distant stars. The National Science Foundation's Very Large Array (VLA) is being used to conduct the survey at 74 MHz, a frequency far lower than those used for conventional radio astronomy. Normally, Earth's ionosphere makes low-frequency radio imaging difficult, but the survey has employed a set of techniques that promise to reveal new categories of deep-sky objects. "We expect to find very distant radio galaxies -- galaxies spewing jets of material at nearly light speed and powered by supermassive black holes," said Joseph Lazio of the Naval Research Laboratory in Washington, DC. "By determining just how distant these radio galaxies are, we will learn how early the black holes formed in the history of the Universe," he added. As for those 'super Jupiters,' they may show up through bursts of radio emission at the frequencies this survey is studying. Other possible catches include previously...

If planets form the way we used to think -- in a relatively smooth condensation out of material surrounding young stars -- then the dust discs from which they form should gradually fade from view. Planetary formation, in other words, should scour a solar system, leaving it relatively free of dust; other than their planets, older stars would show little signs of the material from which their systems were made. But NASA's Spitzer Space Telescope, working in the infrared, is telling a different tale. Studying the dusty discs around 266 nearby stars -- all similar in size but varying in age -- George Rieke of the University of Arizona, Tucson and colleagues have found 71 discs, presumably containing planets. And there goes the old theory, because within the first two hundred million years of a star's life, there is no necessary correlation between the density of the disc and the star's age. Image: The graph above shows the Spitzer findings. Along the vertical axis is the brightness (or...

Planetary systems dominated by huge 'hot Jupiters' -- the kind of systems we've found so far -- are unlikely to contain Earth-like worlds. Massive gas giants close to their star would probably disrupt stable planetary orbits further out, in the habitable zone. But systems with large planets in the 5 AU range, where our Solar System's Jupiter resides, may well have small, rocky inner worlds. And Greg Laughlin, an assistant professor of astronomy and astrophysics at UC Santa Cruz, thinks we'll soon be discovering plenty of systems like these. Laughlin is interested in what he calls 'metallicity,' which he believes is the determining factor in whether or not a system will have gas giants. In fact, the vast majority of planets detected around other stars, at least so far, have circled stars that are metal-rich. The planetary cores have accreted from hydrogen and helium, to be sure, but also from heavier elements that allow the cores to form fairly quickly, within a period of a few...

Is Proxima Centauri really the closest star? Possibly not, a fact that was driven home just last year with the discovery of the red dwarf SO25300.5+165258 (a catchier name would have helped). At 7.8 light years, this tiny neighbor is the third closest to the Sun, but M-class stars are cool and dim, making them hard to detect. Even harder to find are the cool, failed stars known as brown dwarfs. A new NASA mission called the Wide-field Infrared Survey Explorer will scan the sky in infrared looking for such objects, its detectors half a million times more sensitive than previous survey missions. "Approximately two-thirds of nearby stars are too cool to be detected with visible light," said Principal Investigator Dr. Edward Wright of the University of California, Los Angeles, who proposed the new mission to NASA. "The Wide-field Infrared Survey Explorer will see most of them." Another bonus: WISE should be able to spot planet-formation in the making by depicting the dust discs around...