I, for one, wouldn't want to be around to witness what happens when the Earth is faced with an ever expanding Sun that has exhausted its hydrogen fuel. Conventional wisdom has it that the planet will likely be engulfed by what will then become a red giant. Certainly Mercury and Venus will, and the Earth's orbit is close enough that it may meet the same fate. But it's intriguing to learn that other outcomes are possible. Thus news out of Iowa State that the planet known as V 391 Pegasi b has evidently survived just such an encounter with its own star. Larger than Jupiter, the distant world in the constellation Pegasus was once situated at roughly the same distance from its parent that the Earth is from the Sun. That distance has changed over time as the star lost its outer regions in the helium flash, the onset of helium fusion that is produced as hydrogen is exhausted and contraction heats the stellar core. Image: An artist's conception of V 391 Pegasi b as it survives the red giant...

Figuring out planetary habitable zones gets a little less theoretical when we start talking about known systems. And when that system is Gliese 581, the interest level rises considerably. After the initial announcements of a possibly habitable planet around that star, Gliese 581c was later analyzed (in a paper by Werner von Bloh and team) as being too close to its star for liquid water to exist. But another planet, the more distant GL 581d, seemed to hold distinct promise of being in the habitable zone. Now a new paper tackles the question with intriguing results. Petr Chylek and Mario Pérez (Los Alamos National Laboratory) find some reason to think that both inner planets in this system may, under special but feasible conditions, have become suitable for life. The thinking here depends upon analyzing planetary environments as they evolve, with reference to our own Solar System in terms of that evolution. Start with this: Early on, Venus, Earth and Mars lost their original,...

We've found our share of unusual planets in the short time since actual observations could be made. A decade ago, it would have been hard to come up with anything more unexpected that a 'hot Jupiter,' orbiting so close to its parent star that its orbital period is measured in scant days. Add in 'super Earths' around dim red dwarfs and pulsar planets (actually the first type of exoplanets to be discovered) like those around the pulsar PSR 1257+12, and you have a bestiary of odd objects in the making. And now an outburst of gamma and X rays from the direction of the galactic center, one first detected with the Swift satellite's Burst Alert Telescope, gives promise of yet another kind of object. Pulsing in X rays 182.07 times per second, the source is clearly a 'millisecond' pulsar, a neutron star spinning at fantastic rates. Precise studies of the X-ray timing data have revealed the existence of a low-mass companion with a minimum mass of seven Jupiters, but there is wide play in that...

It's long been my belief that getting more private money into space research is essential, given the uncertainties of government funding and the need to inject outside ideas and enthusiasm into the game. We're already seeing what will, I think, become explosive growth in commercial rocket ventures aimed at finding cheaper and better ways to reach low-Earth orbit. On the interstellar front, the Tau Zero Foundation is being built to parlay philanthropic donations into a solid base for funding cutting edge research into advanced propulsion technologies. The hunt for exoplanets also partakes of this largesse, as witness a $600,000 gift from the Gloria and Kenneth Levy Foundation that will fund a new spectrometer designed for the Automated Planet Finder being built at Lick Observatory. The instrument will check twenty-five stars every night, studying 2000 stars within 50 light years over the next decade. Doppler shifts in the wavelengths of starlight provide the telltale signs of an...

The Rossiter-McLaughlin effect is an evolving tool for exoplanet research, one that has already begun to pay off. We recently looked at a paper studying whether this quirk of radial velocity methods could help in the detection of a terrestrial-class planet. The effect causes a distortion in radial velocity data during a planetary transit, one that seems to indicate a change in the velocity of the star under study. But in reality there is no change -- what observers see is the effect of the transiting planet on the starlight, as shown in the diagram below. It turns out the effect might be useful in finding planets larger than two Earth radii, but perhaps less so with smaller worlds. However, new work by a Japanese/American team using the Subaru Telescope points to a different observational capability. Observing the extrasolar system TrES-1, the team has been able to measure the angle between the parent star's spin axis and the planet's orbital axis, only the third time such an...