New Extrasolar Planet Photos to Shake Up Astronomy

Exoplanet Sara (8:36 AM): Yes. First there's a huge dust ring around the star, that is made from colliding rocky bodies.
The planet has stirred up the dust ring, and shaped it in a way that only a planet could. Second, the planet itself seems to have a big "envelope" -- the study's authors think it might be a ring system, but we can't be sure.
Fomalhaut's dust ring is breathtaking, by the way -- you should post an image of it.

Dave on Earth (8:37 AM): You bet :)
Was about to ask you this yesterday before we disconnected: How would you say these two papers will impact the search for -- and understanding of -- exoplanets?

Exoplanet Sara (8:40 AM): Wow -- that's a great question.
There are many different ways to look for exoplanets. Two of my favorite sayings: "All roads lead to a terrestrial planet finder telescope" and "A terrestrial planet finder telescope was not built in a day!"
The discoveries are the first "direct images" of planets that everyone will agree are planets. We want to find terrestrial planets like Earth and Venus with the same technique in the future.
Because the direct imaging of Earths is a long way off, we're banking on other techniques for now.
People aren't going to drop what they are doing and go for the new technique...
It's as if you are building your own new house. Someone else completes an architectural wonder, and you can't catch up to that -- but you keep on building your house knowing it will also result in something fantastic.

Dave on Earth (8:44 AM): What kinds of exoplanet-hunting techniques are we talking about here?

Exoplanet Sara (8:47 AM): To see an Earth is not so hard, the problem is the hugely bright star next to it.
It's like looking for a firefly six feet from a searchlight, and both are 2,600 miles away, or from New York to Los Angeles!

Dave on Earth (8:48 AM): That's a pretty striking analogy...

Exoplanet Sara (8:48 AM): A much easier way to find Earths: Wait for exoplanets to block a tiny bit of the star's light. That's what we call the "transit technique".

Dave on Earth (8:52 AM): Thanks.
So there's direct imaging, the transit technique and I've also heard of gravitational ways (where you see how a planet tugs on its star).
And recently I've heard of some new methods -- a "comb" of sorts.

Exoplanet Sara (8:54 AM): Yes. What's really happening is that the planet and star are both orbiting each other -- we call it the "common center of mass."
But because the star is so big, it moves only a tiny bit, almost like a seesaw: The lighter person moves a lot when the big person only moves a little.
That's how most exoplanets have been found.
Maybe we should say "All techniques lead to Earths".
We can only find Earths with the "wobble" technique if we can precisely measure a star's wobble from a planet's motion. The comb is just a new way to make a better measurement.

Dave on Earth (8:55 AM): Seems straightforward enough.
Now you mentioned working on Kepler -- what's the gist of that telescope?

Exoplanet Sara (8:59 AM): Kepler uses the transit technique and speaking of which, I'm on my way to the Kepler team meeting shortly!
Kepler will watch 100,000 stars at once, for up to four years -- it's doing that to look for a teensy drop in brightness that repeats once each year, caused by an Earth-like planet going in front of a star like the sun.

Dave on Earth (9:00 AM): So we really are looking for Earth-like planets -- down to the same year :)
My last two questions:
1) What's your favorite exoplanet?
2) Why do we study exoplanets if humanity isn't likely to ever reach any?

Exoplanet Sara (9:01 AM): 1) My favorite planet is yet to be discovered -- it's the Earth twin out there waiting to be found.

Exoplanet Sara (9:03 AM): 2) We all want to know where we came from. The search for Earths is part of the story of the origins of humanity.
How were stars and planets formed? How did the ingredients for life to arise? And we want to know are other Earths are out there, and do they have signs of life?

Dave on Earth (9:05 AM): I know I said two questions, but I need to ask this:
How much longer do you guess it will be until we find your favorite planet?

Exoplanet Sara (9:06 AM): Discovery Space readers should come to the New York City to the ninth-annual Isaac Asimov Memorial Panel Debate at the Rose Planetarium.
It's Tuesday March 10, 2009 in the evening. It's tentatively titled: "The New Solar System"
Weill likely be debating, among other things, Pluto's planet status and how the new exoplanets challenge our definition of the word planet.

Dave on Earth (9:06 AM): I'll definitely be there, and hopefully some readers will show up, too.

Exoplanet Sara (9:06 AM): As for that last question: We'll find a planet like Earth in my lifetime.
But I expect to live a very long time!
Seriously though, if we are generous with what we call an Earth, we're literally expecting to find a potentially habitable planet any day (a big Earth transiting a very small star).

Dave on Earth (9:07 AM): Thanks again for doing this -- twice!

Exoplanet Sara (9:08 AM): You're very welcome. Talk to you next time!

Article posted November 13, 2008.

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