NASA‘s Kepler mission and UF astronomer find two new planets orbiting double suns

Published on UF News, January 11th 2012.

Using data from NASA’s Kepler mission, a team that includes a University of Florida astronomer has discovered two new planets orbiting double star systems, something that had never been seen until last September.

The newly confirmed planets, called Kepler-34b and Kepler-35b, will be announced in Wednesday’s online edition of the journal Nature, said Eric B. Ford, UF associate professor of astronomy. William F. Welsh, associate professor at San Diego State University, is the lead author on the paper.

An artist's rendition of the Kepler-35 planetary system, in which a Saturn-size planet orbits a pair of stars.
Image credit: Lynette Cook / extrasolar.spaceart.org

Kepler-34b and Kepler-35b both orbit a “binary star.” They are actually a pair of gravitationally bound stars that orbit each other. While the existence of such bodies, called “circumbinary planets,” had long been predicted, they remained just a theory until the team discovered Kepler-16b in September 2011. They dubbed Kepler-16b “Tatooine” because of its resemblance to the two-sun world depicted in the “Star Wars” film series.

“We have long believed these kinds of planets to be possible, but they have been very difficult to detect for various technical reasons,” Ford said. “With the discoveries of Kepler-16b, 34b and 35b, the Kepler mission has shown that the galaxy abounds with millions of planets orbiting two stars.”

The planets were discovered by measuring the star light decrease as the planets pass in front of, or transit, either of the two stars. Kepler also measures the star light decrease when one of the stars passes in front of the other. The mutual gravitational tugs of the stars and planets cause the times of the transits to deviate from a regular schedule, allowing astronomers to confirm the planet and measure its mass.

Both planets are low-density gas giants, comparable in size to Jupiter, but much less massive. Compared to Jupiter, Kepler-34 is about 24 percent smaller in size, but has 78 percent less mass. It can complete a full orbit in 288 terrestrial days. Kepler-35 is about 26 percent smaller, has 88 percent less mass, and completes its orbit around the stars much faster – just 131 days.

The astronomers believe the planets are made primarily of hydrogen and too hot to sustain life.

“Circumbinary planets can have much more complex climates, since the distance between the planet and each star change significantly during each orbital period, the length of an alien planet’s year,” Ford said. “For Kepler-35b, the amount of incoming star light changes by over 50 percent within a single Earth year. For Kepler-34b, each Earth-year brings ‘summers’ with 2.3 times as much star light as winters. Over the course of a year, the change in the amount of sunlight heating the Earth varies by only 6 percent.”

NASA’s Kepler mission, which began in March 2009, uses a 1-meter space telescope trained on one small portion of the Milky Way for several years. Astronomers analyze data from the telescope for periodic dimming that indicates a planet crossing in front of its host star. The mission’s goal is to find the frequency of Earth-size planets in the habitable zone of their host stars – where a planet might have liquid water on its surface.

Most Sun-like stars in the galaxy are not alone, like the Earth’s sun, but have a “dance partner,” forming a binary system or binary star. Kepler has already identified about 2,165 eclipsing binaries, of the more than 160,000 stars being observed.

NASA originally planned to stop receiving data from the Kepler spacecraft in November 2012.

“Astronomers are practically begging NASA to extend the Kepler mission until 2016, so it can characterize the masses and orbits of Earth-size planets in the habitable zone. Kepler is revolutionizing so many fields, not just planetary science,” Ford said. “It would be a shame not to maximize the scientific return of this great observatory. Hopefully common sense will prevail and the mission will continue.”

The public can contribute to searching for planets using real Kepler data by visiting planethunters.org, which works with the latest versión of Internet Explorer, Chrome and Firefox. For additional information, downloadable slides, and full resolution versions of artwork after the embargo lifts, please see http://sdsu.edu/kepler. For more information about the Kepler mission, visit: http://www.nasa.gov/kepler.

Follow this link to see the original UF press release.

Graduate Students: Dan Li

“Six years ago, I wouldn’t have thought I was going to become an astronomer, but sometimes things change.” That’s what Dan Li says.

Dan Li is from China. He graduated from Tsinghua University in 2003 with a major on precision instrumentation. After spending three years at the Academy of Science and National Astronomical Observatories of China, working on astronomical infrared instrumentation, he developed a taste for astronomy and its tools.

“I found that astronomical telescopes are probably the best thing that combines mechanics and optics. I loved both, so I decided to pursue a career in Astronomy in order to keep improving my instrument-building skills.” Dan recalls.

But according to Dan, Chinese astronomy is more focused into theoretical research. “If you want to do cutting edge observational work, there are more opportunities in the U.S. to access the high end facilities around the world.” he explains.

For this reason, Dan applied to several U.S. schools and got accepted in many of them. He was seduced by UF Astronomy Department’s instrumentation program and now he is on his fifth year here.

Talking to him, it seems like he is happy with his choice “I think this is a very good department. It has they right size and people are very friendly, so you know every student and every professor. It also has a very strong background in instrumentation building and that allows students to use a lot of facilities around the world.” he says “Also, Gainesville has a very good climate and a clean environment. It is not a big city, not too noisy and a very interesting spot. In Florida you can visit many nice places both in the Gulf and in the Atlantic. I have two main hobbies, travelling and railroads. Here I can enjoy both.”

Dan Li works on his thesis under the advice of Professor Charlie Telesco. He studies protoplanetary discs (discs of dust floating around young stars) around certain type of stars called “Herbig Ae/Be” stars. On this kind of star, the disc is very suitable for mid infra-red observation, allowing scientists to learn more about the planet formation processes that happen on them. Prof. Telesco is the lead investigator of some of the most important mid IR instruments around the world, and that gives Dan access to that instrumentation. “This is a very interesting topic, as exoplanetary systems are very popular in nowadays astronomy.” Dan says.

Dan also works on the commissioning of CanariCam, a high tech, heat sensitive camera, built by Prof. Telesco. This is instrument was created to work on the world’s greatest optical telescope, the Gran Telescopio Canarias (GTC), located in La Palma, Spain. This instrument will allow peering through obscuring interstellar dust with unprecedented accuracy.

Due to his work Dan was invited to attend to the GTC meeting just held in the island of La Palma. “It was very interesting for me, as my work is tightly related to the GTC and CanariCam. Many instrumentation groups gave talks about their plans for this very special telescope. There are a lot of great ideas and projects going on. From the information I got and from my own personal opinion, I think that the GTC will do very well soon.”

Dan Li is currently focused on getting his PhD degree, which will happen in one or two years. Eventually, he wishes to become a professor and do research. In the long term he would like to do something for his home country, China, and contribute to reduce the gap between Chinese and Western astronomy.

“Being an astronomer is not a job one does just for survival. I love the starry nights and the feeling you get when you are up in the mountain, under the shining stars and the Milky Way. Then I realize that I really enjoy my job and this is something that not everyone can have in their lives.”

Graduate Students: Jesus Martinez

Jesus Martinez says his life is marked by places where he has lived. “When you are a child you want to be part of a place. Have some stability.” he says.

After he was born, his family lived in Madrid for five years, then Germany for three years and after those, four years in Mexico. Then he went to Seville for College, expending his last year in Germany, and now he is 26 and is in Gainesville for his PhD.

The reason, at least in the early years, was his father. He is a physicist, so his life and his family’s, was conditioned by the requirements of an early scientific career. “My father was anomalous in the scientific world, because I was born when he was only 20 years old, so I had to follow him: first his doctorate in Madrid and then several post-doctoral contracts.” Jesus explains.

With this background, is natural that young Jesus didn’t want to be a scientist. But, when he was seventeen and had to decide what to study in College, he chose physics. “I realized that I really liked it. I guess I knew what it was and had lived with it all my life to have it very clear. Also, as an adult, I started to value the great experience that has been to grow up in different cultures.” he admits.

His main motivation was, and still is, to understand how the universe works. “To answer the great questions: where does the universe come from and how does it work. On graduate school I decided to focus on the biggest scale of all that, which is astrophysics or cosmology.”

Jesus’ PhD is funded by a grant that UF gives each year to a Spanish student, as part of its participation on the Gran Telescopio Canarias telescope, the world largest optical telescope, built in the Canary Islands (Spain).

He had another offers in Germany but he decided to come here for many reasons. First he had more freedom to choose for his research. “Here is like having a menu to choose from. In Spain and in Europe, grants are subject to a specific project, so you cannot choose. I also wanted to go to a new place.” Jesus says. “A thing I do really like here is that everybody encourages you to go on with your research. People are very supportive.”

This year, Jesus has published his first paper, based on data from the GTC. “My advisor, Rafael Guzman, and I sent a proposal and it got accepted. Then I had to analyse all the data and we had very good results. This was a very long process, especially until it got published.”

Jesus feels that the moment when he was told his paper was accepted for being published was the best of his recently started scientific career: “The reason to be of a scientist is to publish papers. You can do a lot of work, but if nothing gets published, is like you haven’t done anything. It doesn’t count. One doesn’t get to publish very often, so it’s always great news.”

Jesus says he's happy to be an UF astronomy graduate student. “There are many good astronomy departments in the US. Here we are among the top ones and we have access to the GTC. I am one of the fortunate ones that have had access to the data and could use them for my thesis. This is something that in another institution I probably couldn’t have done.” As a final conclusion, he says “If you like science and know what to expect from a scientific career, go for it.”

The Observatory

This fine video has been created by Peter Nguyen, a physics and astronomy undergraduate in his final semester.

He enjoys photography and is currently enroled in the graduate observational techniques course taught by Dr. Telesco, which provides him with plenty of time out at the Department’s Rosemary Hill Observatory (RHO).

It was there that he shot “The Observatory” over the past month. “A lot of sleepless and sometimes chilly nights went into making this. And as you can see from the clouds, not much useful observing!” Peter says. Early in the video, Nguyen captures a lightning storm in the distance, which luckily stayed far enough away from RHO to do some observing this night.

Peter also had some help the last few nights. Stefan O’Dougherty, who graduated from UF Astronomy in May, visited to help, and contributed the motion shots using his telescope mount. The last time these two students paired up, a NASA Astronomy Picture of theDay was the result. Whatever happens with this video, Peter is still happy, “I shoot these for fun … I’m glad RHO has such dark skies, relatively. And I’m quite pleased with how beautifully all the time-lapes came together!”

Michael Mumma's lecture available on Youtube

Last Thursday, at Starry Night, we had the opportunity to attend to a lecture by Dr. Michael Mumma titled “The search for life in Mars”. If you missed it, it's available in UF astronomy department’s account in Youtube.

Michael J. Mumma was educated at Franklin and Marshall College (A.B. 1963, Physics), and the University of Pittsburgh (Ph. D. 1970, Physics) and joined NASA’s Goddard Space Flight Center thereafter.

He is founding Director of the Goddard Center for Astrobiology and Senior Scientist in the Solar System Exploration Division.

He thrice received the NASA's rarely given Medal for Exceptional Scientific Achievement; the fist time was in 1988 for originating and developing a concept for detecting cometary parent volatiles by solar infrared fluorescence, with it achieving the first detection of water vapor in comets. He also led the team that discovered the saturated hydrocarbons methane and ethane in comets, being awarded for the second time in 1997 for that work. In 2009 he was awarded for the first definite detection of methane on Mars with the John C. Lindsay Memorial Prize, Goddard’s highest recognition for scientific achievement, and also the NASA’s Medal for the third time.

He is an elected Fellow of the American Physical Society and of the Washington Academy of Sciences. In 1999, the International Astronomical Union named Asteroid 8340 "Michael J. Mumma" in his honor.  He received the Alumni Citation for Distinguished Career Achievement from Franklin & Marshall College, one of only four Alumni so honored in 2008.

During the lecture at Starry Night
“FLMNH photo by Kristen Grace.”