The Spitzer Space Telescope has peered into the Orion nebula with striking results: nearly 2300 planet-forming disks in the overall Orion cloud complex, a star-forming region some 1450 light years from Earth. This is where infrared truly shines, for such disks are too small to be seen with visible-light telescopes. But Spitzer is made to order for picking up the infrared signature of warm dust, giving us an unprecedented look at solar system formation in the aggregate. The image below gives a glimpse, but be sure to click to enlarge the photograph for a bit more detail. Thomas Megeath (University of Toledo, OH) likens the research to a census of potential solar systems, saying "...we want to know how many are born in the cities, how many in small towns, and how many out in the countryside." Megeath and colleagues discovered that 60 percent of the disk-bearing stars in the Orion cloud complex are found in clusters of hundreds of stars, while 15 percent exist in much smaller groupings,...

Centauri A and B continue to stand out as likely venues for terrestrial planets. What a change since the days when it was thought orbits in binary systems like this one would be completely unstable. Today we believe that both the major Centauri stars could support small, rocky worlds within about 4 AU, and that such planets are as likely, if not more so, to form there as around our own Sun. The latter insight emerges directly from the work of Elisa Quintana and Jack Lissauer. Add to that two other factors: At UC-Santa Cruz, Greg Laughlin and Jeremy Wertheimer have shown that Proxima Centauri could perturb the debris disk surrounding the Centauri stars enough to deliver volatiles to inner worlds there. Laughlin has been arguing the Centauri case for some time now, discussing not just the Proxima factor but pointing as well to the metallicity of Alpha Centauri, which is high enough to provide the kind of materials needed to form planets analogous to Earth. Keen on detecting such a...

Gravitational microlensing is a fascinating way to find exoplanets, provided you're not worried about nearby targets. For the best way to do microlensing of this sort is to work with a crowded starfield, which means looking toward galactic center, where stars are numerous and distant enough that their lensing events can be studied. You're hoping to find a star that passes in front of another as seen from Earth, in which case the gravity of the foreground star sets up the gravitational lensing effects that magnify the light of the background star. Thus OGLE-2003-BLG-235L, which displayed a planetary companion that was discovered in 2003 using ground-based observations. The oddity here is that while the planet produced an additional brightening of the background star, thus confirming its existence, astronomers weren't sure about the identity of the star it circled. It has taken two years and new observations by the Hubble Space Telescope to pin down OGLE-2003-BLG-235L -- the foreground...

We know all too little about planetary-mass objects -- planemos, as Centauri Dreams is learning to call them -- that are not associated with a star. But we've learned a bit more with the discovery of an unusual binary system. Discovered in optical imagery taken by the European Southern Observatory's 3.5 meter instrument in La Silla (Chile), Oph162225-240515 (Oph1622 for short) is a 14-Jupiter mass planemo apparently orbited by a companion of about half that mass. "This is a truly remarkable pair of twins - each weighing some hundred times less than our sun," says Ray Jayawardhana, an associate professor of astronomy and astrophysics at the University of Toronto. "Their mere existence is a surprise, and their origin and fate a bit of a mystery." Following up the find with optical spectra and infrared work, Jayawardhana and ESO's Valentin Ivanov established that both members of the pair are at the same distance from the Sun and far too cool to be stars. They're also young, perhaps a...