The exoplanet hunt has entered a significant new phase, one focused on transiting planets and the useful things we can learn about their physical properties and atmospheres through such events. Driven by CoRoT and Kepler, we’re now in position to use those transits to spot smaller worlds than ever, down to terrestrial size, and naturally the focus is on Earth analogs located in the habitable zones of their stars.
So think of it this way: We’ve gone from a broad-brush approach based largely on radial velocity methods to a more selective hunt, one that will take us to the realm of planets that can have liquid water on their surfaces and aren’t so different from our own. Not that the continuing work on characterizing planetary systems is of any less importance, but we’ve found plenty of gas giants, and now we’re trying to learn something about how common these smaller worlds may be.
Putting an exclamation point on this focus is a conference called Pathways Towards Habitable Planets, to be held in Barcelona from the 14th to the 18th of this month. The European Blue Dots Team (BDT) is an initiative made up of researchers who focus on finding habitable worlds, with international assistance. The purpose of its Barcelona conclave is to bring together space agencies from around the world to discuss how to learn more about planets of the kind Kepler and CoRoT may find.
A glance through the program shows how wide-ranging this discussion is likely to be. Some examples: Differing cultural views on the ‘are we alone’ question (Jean Schneider, CNRS-Paris Observatory). Tidal constraints on habitability (that one, as you might expect from discussions here) is from Rory Barnes (University of Arizona). A coronagraph concept for direct imaging and spectroscopy of exoplanetary systems (John Trauger, JPL). And an old Centauri Dreams friend: David Kipping (University College, London) discussing habitable exomoons.
Image: One way to study habitable exoplanets is through a space telescope coupled with a starshade concept like New Worlds Observer. This is a simulated image of the inner solar system taken at 10 parsecs with a 4-meter telescope. The Earth is clearly visible as a pale, blue dot. Venus is harder to make out due to the zodiacal light. The inclination of this image is 60 degrees. Credit: Phil Oakley.
The proceedings are to be published in the spring, but we should have copies of some of these papers for review in the near future. It’s good to see that Webster Cash (University of Colorado, Boulder) will be presenting the latest on his New Worlds Observer, a space-based starshade design that would be able to perform spectroscopy on exoplanetary light to look for biological markers. Long championed here, this powerful concept has had its ups and downs re funding but clearly remains viable.