Wednesday, April 4, 2012

The Landscape in the Sky (WW106)


This Monday past marks the first interview of Parshati Patel, as she becomes the fourth member of the WW crew to try her hand at interviewing! She certainly couldn't have picked a better subject then Dr. Travis Barman (pictured above) of the Lowell Observatory and the results speak for themselves. If you haven't had the chance to listen, drop by the WW page and pick up a copy of the interview!

The solar system has, for a long time, been our own backyard to astronomers - out beyond our home but not as exotic or enticing as that which lies beyond. But, exo-planets are an interesting cutting-edge convergence of Planetary Science and mainstream Astronomy each of which counts this field as their own. It's a productive rivalry with "Planetary Science" missions like Kepler, a space mission currently conducting a planetary census, coordinating with "Astrophysics" telescopes on the ground to confirm discoveries of new worlds. The statistical results then get put into models, such as those of the Nice group, that help to tell us why our own solar system looks the way it does today. By understanding the initial conditions required to make our solar system "work" and how ours differs from others, we can get a handle on the process more generally.

It's a fascinating study and the explosion in planets over the last decade is nothing less than breath-taking. The expansion in techniques is no less so. While it may be awhile before we get to see them up close and know them the way we do our own solar system, Dr. Barman's direct images of exoplanets far from their parent stars brings to mind what Uranus and Neptune might have looked like a century ago. Who knows what the future in this fast-breaking field will bring? I hope you enjoy the episode, and, as always, my introduction is underneath the cut.





More varied than any landscape was the landscape in the sky, with islands of gold and silver, peninsulas of apricot and rose against a background of many shades of turquoise and azure. You’re listening to Western Worlds!

Hello and welcome back for another conversation here on Western Worlds, an AFM*Original show heard right here on Astronomy.fm. My name is Dr. John and I’m coming to you this week as every week from the Centre for Planetary Science and Exploration at Western University just 10.4 light years from Epsilon Eridani B in London, Ontario, Canada.

Tonight’s quote is attributed to Cecil Beaton and evokes the metaphor of stars as isolated islands in a vast sea of space. Emphasizing that image is our musical selection “Sea of Stars” by Oceans Apart. Around many of those stars in that vast and infinite ocean, we now know, are the shoals that are planets.  The very first was found in 1992 and there are now orders of magnitude more planets known outside of our solar system than inside of it. In the last twenty years our understanding of solar systems in a general sense has increased in leaps and bounds and so have our techniques to search for these places. Fascinatingly, each technique is sensitive to a particular kind of world.

We have learned that some of these planets are dangerous reefs, tortured gas giants that have ventured too close to their parent star. We call these planets “hot jupiters” and while they may not offer shelter to future travellers, even at a distance we can begin to probe their atmospheres. We find these places through a technique known as Radial Velocity – we actually look for the wobble in the parent star caused by the titanic struggle between these objects.

Other planets are located in so-called goldilocks zones, close enough for warmth but not so close that they are burnt by their solar campfire. These places are the best hope of finding life outside of our Earth, especially if the bodies are “Super-Earth” sized or smaller. These more distant and often smaller bodies are best detected using the transit method where we observe the light coming from a star and look for the dimming that occurs when a planet passes in front of the solar disk.

But still other planets inhabit calmer waters, far from their parent stars. In some cases these bodies can even be imaged directly, much as planets in our own solar system are. That kind of photography is the business of tonight’s guest, Travis Barman, an astronomer at the Lowell Observatory in Arizona who makes a living through the precise science of images, much as Sir Beaton did. Our own Parshati Patel sat down with Dr. Barman recently to discuss his work to find and understand these extra solar planets.

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