Astronomers to Explore ‘Extreme Solar Systems’

As solar systems go, the one we live in is pretty boring. In the “Hitchhiker’s Guide” by the great Douglas Adams, our neighborhood was described as being “far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the galaxy.” (Our planet was deemed “mostly harmless.”)

But planets and stars can be found in some pretty remarkable configurations. And beginning this weekend, an international conference dedicated to “Extreme Solar Systems” will be held on Hawaii Island, with a complementary public talk scheduled for next Wednesday in Honolulu.

What constitutes an “extreme” solar system? One with two stars, perhaps?

“For those who are interested in science fiction, they might remember Luke Skywalker coming out of his den and walking toward the horizon and seeing two suns,” said Nader Haghighipour, a researcher at the University of Hawaii at Manoa Institute for Astronomy, on tonight’s Bytemarks Cafe. “Well, that was science fiction many years ago, but a small group of us have been promoting the idea that science fiction is not entirely fiction and that there’s actually science behind it.”

Haghighipour had been adamant for more than 20 years that “circumbinary” solar systems existed, but it wasn’t until observing instruments and scientific advances made it possible to find one. And the launch of the Kepler space observatory in 2009 was a major turning point. Kepler scientists started discovering new exoplanets right out of the gate, and to date the space telescope has helped find over 1,000 exoplanets in about 440 star systems (with another 3,100 candidates waiting to be confirmed).

Haghighipour was poring over the Kepler data as well.

“We saw something very interesting about one specific binary star system: we saw that when the two stars go around each other, the light of each one of them dims for a very short amount of time and a very short amount of intensity,” he recalled. “Being promoters of planets with more than one sun, that was the first thing that occurred to us, that it may be a planet that was blocking the light coming from each one of the stars.”

Still, astronomy is a field that demands lots of study and independent confirmation before declaring any discovery.

“Three years, four years of data coming from Kepler helped us to get that model more and more solid, and eventually we could make predictions of when would be the next time the planet will go around those stars,” Haghighipour said. “When we discovered that, that was the proof.”

The news made global headlines. Since then, he’s helped discover ten more planets that orbit two stars.

Haghighipour explained how a circumbinary system would look.

“In the context of our solar system, think of Mercury being another sun, and Jupiter and Earth going around both of them at the same time,” he said. “You wake up in the morning, you have two suns out there, you have two shadows when you walk, and just imagine one of the suns sets, the other stays up, or they both go down.”

Of course, to see a two-sun sunset, the solar system needs to have planets that can support life. And with so many exoplanets now catalogued by astronomers, it was inevitable that some would be found in the ‘Goldilocks Zone’ around their stars — an orbit not too cold and not too hot for life to exist.

“So far we have discovered ten of them, and we are going to announce two new ones next week,” Haghighipour teased. “And among these ten, three of them are right in the habitable zone: they’re large, they’re as big as Jupiter, so they themselves cannot be habitable, but similar to our Jupiter, they may have moons that are big enough to be habitable.”

The “Extreme Solar Systems” conference is only the third such international gathering, following meetings in Greece in 2007 and Wyoming in 2011. But the Hawaii meeting marks the 20th anniversary of the discovery of the first extra-solar planets. More than 300 “hardcore astronomers” will spend a week at the Waikoloa Marriott exploring hundreds of poster presentations, dozens of scientific sessions, and many talks.

Fortunately, Honolulu residents will also have a chance to soak up stories about unusual star systems. On Wednesday, Dec. 2, the UH Institute for Astronomy is hosting a “Frontiers of Astronomy” public talk at the UH Manoa Art Auditorium. Titled simply “Exoplanets,” the event will feature four planet hunters who are also presenting at the Big Island conference: Haghighipour, Andrew Howard, Paul Kalas from Berkeley and Josh Winn from MIT.

Each researcher represents a different area of solar system research, and each will give a 10 minute talk. Then the floor will be opened to audience questions. The event is free and open to the public and starts at 7:30 p.m.

For more information on the “Extreme Solar Systems” conference, visit the official website. For more information on the public talk on Wednesday, visit ifa.hawaii.edu. You can also follow @UHIfA on Twitter or connect with the institute on Facebook.

You can listen to our full interview with here:

Illustrations courtesy Ben Bromley/University of Utah and Mark Garlick via UH Institute for Astronomy.