Greg Laughlin's systemic site, indispensable for those studying exoplanet detections, now offers a close look at Proxima Centauri, at 4.22 light years the closest known star to the Sun. Intriguing facts include these: While holding about 11 percent of the Sun's mass, Proxima has an average density several times that of lead (the Sun's average density is about 1.4 times that of water) Proxima's total luminosity is a thousand times less than the Sun's Because radiation alone cannot get Proxima's fusion energy from its interior to the surface, the star relies on convection -- the motion of stellar gases physically takes energy away from the core (by contrast, the Sun has a radiative core) All of which has powerful consequences, especially in terms of longevity -- Proxima Centauri will still be shining two trillion years from now. You'll want to read the entire post, which goes into the details of a paper Laughlin wrote (with Peter Bodenheimer and Fred Adams) that examines the fate of...

A fascinating post by Anthony Kendall cites the reasons why Terrestrial Planet Finder is such an important mission and goes on to call for NASA's being broken into separate entities, to make missions like this more likely to launch. From the Anthonares weblog: Gradually, constructing, launching, and operating missions in Earth orbits or in Lagrange points should be taken over by consortia similar to those that operate ground-based facilities today. As commercial satellite companies have demonstrated, they are more than capable of managing their own facilities. NASA's deep space expertise will necessitate the existence of an unmanned space probe agency for several decades at least, and perhaps indefinitely as we look to explore the stars. The TPF missions could be the first in step in this process. If the scientific community wants them badly enough, they have the lobbying ability (as demonstrated with Hubble and New Horizons) to get Congress to fund them. Since private consortia will...

The key lesson of exoplanetary science is surely humility. Over and over again, starting with the discovery of the first 'hot Jupiters,' we've been brought face to face with the fact that assumptions long enshrined in our thinking have to be reevaluated. Thus it's no surprise to learn of a new study identifying what appear to be enormous debris disks around two giant stars. In the past, stars of their size were considered unlikely candidates for planetary systems. The stars are R 66 and R 126, both located in the Large Magellanic Cloud; the former is 30 times more massive than our Sun, the latter 70 times. Both are thought to be descendants of the massive objects called type O stars, large enough that, if they were located in our own Solar System, they would swallow all the inner planets including Earth. Image: This illustration compares the size of a gargantuan star and its surrounding dusty disk (top) to that of our solar system. Monstrous disks like this one were discovered around...

Anyone involved in exoplanetary science shares a common dream: a view of a blue and green world returned from an advanced imaging system of the sort that may one day fly aboard Terrestrial Planet Finder or other missions. But as we wait for breakthroughs in space-based hardware, planetary detections keep occurring. And astronomer Greg Laughlin (University of California, Santa Cruz) has a thought on what we might find using today's technologies. Laughlin notes that that nine extrasolar planets are known to transit their parent stars (i.e., they pass in front of the star as seen from Earth). "It would be nice to find a transiting planet with a longer period," he adds. "Preferably, this would be a giant planet with towering thunderstorms and warm, drenching rains, and orbited by a habitable Earth-sized moon that we could detect with HST photometry." Nice indeed, for that moon would be our first candidate for a life-bearing world in the terrestrial mode, a real coup for transit studies....