Tag Archive for planetary

Study by Redfield, Wyman MA ’11 Published in Astrophysical Journal, Forbes

Seth Redfield

Seth Redfield

Seth Redfield, assistant professor of astronomy, and Katy Wyman MA ’11, recently co-authored a paper that will appear in the Aug. 10 Astrophysical Journal, detailing several hundred spectral line measurements out to bright stars within 326 light years of our sun. Wyman is now employed at the Harvard-Smithsonian Center for Astrophysics.

The study also appeared in the July 28 edition of Forbes in an article titled “Looking In The Sun’s Rear-View Mirror: A New Map Of The Local Interstellar Medium.”

The first comprehensive map of the local interstellar medium — the gas drifting between the nearest stars — “will not only help theorists better understand the dynamics of our tiny swath of the galaxy, but represents the first crucial step in paving the way for interstellar travel,” the article reports.

Redfield, Wyman and their colleagues made their primary observations through the Hubble Space Telescope, the McDonald Observatory in Texas and the Australian Astronomical Observatory in New South Wales. Redfield says the plan is to publish a revised morphological model in the next six months.

Read the Forbes article online here.

Gomes ’06 Published in June Geology Journal

Maya Gomes '06 working on her research.

Maya Gomes ’06 working on her research.”

Maya Gomes ’06 and her co-author Matthew Hurtgen published their paper, “Sulfur isotope systematics in a permanently euxinic, low-sulfate lake: Evaluating the importance of the reservoir effect in modern and ancient oceans,” in the June issue of the journal, Geology. In the paper, the authors present data that shows how geologists can use sulfur isotope compositions of marine sediments to discover variations in oceanic sulfate levels through Earth history.

Gomes explained that the paper is very important to researchers who study the climate of the past because “marine sulfate levels play a role in regulating oxygen and carbon dioxide levels in the ocean-atmosphere system, which has implications for habitability and climate.”

Maya Gomes

Maya Gomes

“I fell in love with geology and research when I was an earth and environmental science major at Wes,” she said.

Gomes wants to share her work with the Wesleyan community because she hopes that it will show that the strong foundation she received in science while attending Wesleyan University has allowed her to “pursue high quality research as a PhD student.

“My thesis adviser at Wesleyan was [Associate Professor of Earth and Environmental Sciences] Marty Gilmore,” Gomes notes. “She served as an excellent mentor to me while at Wes and beyond.  However, I was also advised by and heavily influenced by many other members of the department, including Professors Johan Varekamp, Jim Greenwood, and Suzanne O’Connell.”

The paper is online here.

Hughes Studies Formation, Evolution of Planetary Systems

Meredith Hughes, assistant professor of astronomy, works with students on a small radio telescope, located on the roof of the Van Vleck Observatory.

Meredith Hughes, assistant professor of astronomy, works with students on a small radio telescope, located on the roof of the Van Vleck Observatory.

(Contributed by Jim Smith)

Meredith Hughes was one of those kids drawn to science and nature. But growing up in small-town Rhode Island, she didn’t know any scientists.

“The people I knew who liked science were teachers and doctors,” recalled Hughes, a new assistant professor of astronomy at Wesleyan this year. “So I figured that’s probably what I’d be.”

Then, during her junior year of high school, a patient of her mother, a women’s health nurse practitioner, recommended a program for budding scientists called The Summer Science Program (SSP). Hughes applied, and became one of 25 students from around the world to spend the summer under the pristine skies of Ojai, California. “We spent the summer determining the orbit of 4 Vesta, the second largest object in the Asteroid Belt,” she said. “It was my first exposure to professional scientists and real research, and by the time the summer was over I had begun to think that maybe a career in science wasn’t such a crazy idea.”

Little more than a year later, she was enrolled at Yale. Despite the inroads into astrophysics she had made at SSP, she embraced the philosophy of a liberal arts education and spent her freshman year avoiding astronomy and instead exploring fields as diverse as cognitive science and music theory. During the summer  she had an opportunity to stay in New Haven and do astronomical research with Professor Meg Urry, director of the Yale Center for Astronomy and Astrophysics. Hughes found it exhilarating to apply the physics she had learned in the classroom to investigating the properties of the supermassive black holes at the centers of distant galaxies.

“After that summer, I was hooked,” she said. She went on to complete A.M.  and Ph.D. degrees in astronomy at Harvard in 2007 and 2010, earning the department’s Fireman Fellowship for an outstanding Ph.D. thesis in the field of experimental astrophysics.

After Harvard, she accepted a postdoctoral fellowship with the Miller Institute at the University of California-Berkeley. Former Miller Fellows have included Nobel laureates and Fields medalists, but Hughes says she was most excited to follow in the footsteps of former Miller Fellow Carl Sagan. “His career was exemplary in combining a deep understanding of research with an incredible gift at communicating his knowledge and passion to non-scientists, which is a combination I strive to emulate,” Hughes said. She was at Berkeley when she learned about the opening at Wesleyan that offered what she said was “exactly the balance of teaching and research I was looking for.”

New Radio Telescope to Benefit Astronomy Research

A new telescope at Van Vleck Observatory saw its first light on May 1. The ribbon-cutting ceremony was attended by staff and students of the Astronomy Department and the Science Machine Shop.

Astronomy students and faculty celebrated the completion of a new small radio telescope (SRT) on May 1 during a ribbon-cutting ceremony. This is Wesleyan’s first radio telescope, joining three optical telescopes housed at the Van Vleck Observatory on Foss Hill.

Radio telescopes are highly complementary to optical telescopes. Able to see through cloud cover, they are not limited by weather. Also, in a "radio sky," the remnants of exploding stars and distant supermassive black holes shine brightly.

Radio telescopes are highly complementary to optical telescopes. Able to see through cloud cover, they are not limited by weather. Also, in a “radio sky,” the remnants of exploding stars and distant supermassive black holes shine brightly.

Going forward it will allow Wesleyan students to detect more remote radio sources, map galactic rotation and conduct other kinds of astronomical research. It will be an essential tool in the university’s astronomy courses.

This fall, the SRT will allow Wesleyan students and faculty to detect remote radio sources, map galactic rotation and conduct other kinds of astronomical research. It will be an essential tool in the university’s astronomy courses.

Astronomy students and faculty celebrated the new small radio telescope (SRT) on May 1 during a ribbon-cutting ceremony. The SRT has a motorized arm that can position the dish to face any part of the sky. Quasars, pulsars, and the afterglow of the Big Bang have all been discoveries of radio astronomy.

The SRT has a motorized arm that can position the dish to face any part of the sky. Quasars, pulsars, and the afterglow of the Big Bang have all been discoveries of radio astronomy.

Students enrolled in Assistant Professor Meredith Hughes' Radio Astronomy Class created the functional radio telescope in one semester. They followed design specifications for a small radio telescope developed by Alan Rogers at MIT’s Haystack Observatory.

Students enrolled in Assistant Professor Meredith Hughes’ Radio Astronomy Class created the functional radio telescope in one semester. They followed design specifications for a small radio telescope developed by Alan Rogers at MIT’s Haystack Observatory. Wesleyan is the first university to assemble a SRT from upgraded system plans published by Haystack.

Meredith Hughes, assistant professor of astronomy, divided her class into three teams, each of which was responsible for a different part of the telescope. Each team would work separately, acquiring and assembling the components for its part of the telescope.

Hughes, pictured directing the satellite through a computer, divided her class into three teams. Each team was responsible for acquiring and assembling the components for different sections of the telescope.

Of the 10 astronomers who have received Nobel prizes in astronomy, six used radio telescopes in their research.

Of the 10 astronomers who have received Nobel prizes in astronomy, six used radio telescopes in their research.

Classmates, with the help of Astronomy Department faculty, used the new device to detect the sun.

Classmates, with the help of Astronomy Department faculty, used the new device to detect the sun during a “First Light” celebration.

Redfield Invited Speaker at Extrasolar Planets Conference in Germany

Seth Redfield

Seth Redfield, assistant professor of astronomy, spoke on “Properties of the Interstellar Medium Surrounding the Sun and Nearby Stars” during a conference held March 11-15 in the Physikzentrum in Bad Honnef, Germany.

The conference, which was 527th in a series, was sponsored by the Wilhelm und Else Heraeus Stiftung, a German foundation that supports scientific research and education. The topic of the conference was “Plasma and Radiation Environment in Astrospheres and Implications for the Habitability of Extrasolar Planets.”

Summer McNair Scholars Study Water on Mars, Toxins, Black Political Activists

McNair scholar Lavontria Aaron '14 studied "Mars Brine Mineralogy" this summer. Her research was sponsored by the Ronald E. McNair Post Baccalaureate Achievement Program.

McNair scholar Lavontria Aaron ’14 studied “Mars Brine Mineralogy” this summer. Her research was sponsored by the Ronald E. McNair Post Baccalaureate Achievement Program.

By looking at high-resolution images captured by the Mars Reconnaissance Orbiter, scientists are able to see gullies, which are argued to be geologically recent. Because they are most likely formed by water, it is believed that they can answer the question of whether or not there is still “active” water on Mars.

As a summer Wesleyan McNair scholar, astronomy major Lavontria Aaron ’14 used a hyperspectral instrument to determine if the gullies contained minerals (salts) which would be left behind by water brines.

“By examining the spectrum of the brines, we’ll be able to learn more about Mars’ history and possibly man’s future in pursuit of exploring the red planet,” says Aaron, who worked on the project with her faculty advisor Marty Gilmore, chair and associate professor of earth and environmental sciences.

Aaron and her 13 McNair peers are supported by the Ronald E. McNair Post Baccalaureate Achievement Program, which serves students in their second, third, and fourth college semesters. It provides career-oriented activities,

“Evaporating” Planet May Hold Clues to Gas Giants, Other Exoplanets

Seth Redfield, assistant professor of astronomy and Adam Jensen, visiting assistant professor of astronomy, documented an exoplanet that is slowly evaporating “hot hydrogen.”

In a nearby solar system, a planet the size of Jupiter orbiting a star similar to our own sun is doing something that has astrophysicists very intrigued: It’s dissolving–albeit very, very slowly.

The findings are detailed in a study by primary investigators Adam Jensen, visiting assistant professor of astronomy, and Seth Redfield, assistant professor of astronomy. They made the majority of their observations using the 9.2 meter telescope at The University of Texas’s McDonald Observatory. The paper, “A Detection of Ha In An Exoplanetary Exosphere,” will appear in the June 1 issue of The Astrophysical Journal.

Jensen and Redfield studied the planet, HD 189733b which is about the size of Jupiter, orbiting a star 63 light years from Earth.

The planet in question, a gas giant similar in size to Jupiter called HD 189733b, orbits a class K star, which is about 63 light years from Earth–a virtual next-door neighbor in astronomical terms.

What Jensen and Redfield observed was HD 189733b discharging significant amount of atomic hydrogen into space.

“This type of evaporation of atomic hydrogen, or what is called ‘hot hydrogen,’ is something that has never been observed before,” says Redfield. “When we first saw the evidence we thought, ‘Wow, can that be right?’ But more careful analysis and cross-checks confirmed it. At that point we got really excited because we knew we’d found an important phenomenon.”

The orbital path of HD 189733b is 12 times closer to its star (HD 189733) than Mercury is to our own sun (a class G star, and 32 times closer than the Earth is to the sun. While somewhat smaller than the sun, the star HD 189733 is more volatile–often discharging massive solar flares hundreds of miles into space–and dangerously close to HD 189733b.

The astronomers’ observations indicate an interaction between the stellar activity and the planet’s atmosphere. This can have implications for understanding other planetary systems, especially those which may have potentially habitable planets.

That is not the case with HD 189733b, a gas giant orbiting very close to a somewhat volatile star. But is it that very degree of proximity that is causing the planet to slowly evaporate?

“This mass loss is almost certainly due to the proximity of the planet HD 189733b relative to its central star, HD 189733, along with the star’s radiation,” says Jensen. “This isn’t to imply it’s not going to last much longer. It is a very slow evaporation, and ultimately the planet will lose only 1 percent of its mass. Still, that is significant.”

What Jensen, Redfield and other observers contributing to the paper saw to indicate this was a significant spike in spectrographic readings suggesting the planet was shedding significant amounts of hydrogen. They were also able to detect it using visible light–another first. Past detections of hydrogen dissipation, which have been rare, used ultraviolet light.

“We’ve only been able to observe exoplanets for about 20 years, and we’ve detected atmospheres in just a few dozen of those, so this is an exciting finding,” Redfield says. “We’re hoping to do more observations of this planet and others that are similar in their composition and positioning to their stars. This will help us determine how rare of a phenomenon this is.”

The astronomers hope to do further studies at the McDonald Observatory, and perhaps try to book time on the Hubble Telescope, which would afford them the clearest view of HD 189733b.

The astronomers were supported in this study by a grant from the National Science Foundation.

Malamut’s Astronomy Research has been Out of this World

Craig Malamut ’12

In the summer of 2010 Craig Malamut traveled to the Easter Islands to study and photograph a rare solar eclipse. Soon after his eclipse observations were completed, NASA used one of his photographs in their official materials on the event. He also spent a week collaborating with astronomers from the University of Chile in Santiago to study Pluto’s atmosphere as it obscured the light from a faint star. This year, Malamut has coauthored two papers for astronomical journals and is analyzing data from the Hubble Space Telescope on gas and dust clouds lying near the sun and other nearby stars.

It’s the kind two-year research run that many scientists would be proud and excited to have accomplished. But Craig Malamut is not a paid researcher or a member of any faculty. He’s a college student who is still working through his senior year at Wesleyan.

Malamut, an astronomy major, has been working at an advanced level for someone who has yet to earn a bachelor’s degree. While the experience has been intense, he hasn’t been intimidated by the complexity of the work or felt limited by his undergraduate standing. “I’ve felt very prepared for this level of research from the courses, discussions, and advising I received from the astronomy department,” he says. “Professors Herbst, Moran, Redfield, and Kilgard do a great job getting their students involved early in astronomy research, whether at Wesleyan or abroad.”

He also took part in the Keck Northeast Astronomy Consortium Research Experience for Undergraduates (KNAC REU) Williams College. Several members of astronomy faculty also recommended him for the Keck-sponsored program in the Easter Islands.

NASA Funds Greenwood’s Lunar Rock Study

Jim Greenwood

James Greenwood, research associate professor of earth and environmental sciences, received a grant worth $494,517 from NASA. The grant will support his research titled “Water in Lunar Rocks: Petrologic and Isotopic Analyses of Phosphate Minerals in Apollo’s Samples” through June 30, 2014.

Greenwood Mentioned on BBC News Regarding Water in Lunar Rocks

James Greenwood, visiting assistant professor of earth and environmental sciences, was mentioned in a June 14 BBC News science article on “Much More Water Found in Lunar Rocks.”

Greenwood and Professor Lawrence Taylor from the University of Tennessee in Knoxville, have come up with evidence on the origins of lunar water: comets. According to the article, they believe there were a lot of comets flying around at the time of the Moon’s formation, “hitting the little, nascent, early Moon some 4.5 billion years ago.”

Greenwood Finds Water in Moon Rocks

Jim Greenwood, research assistant professor of earth and environmental sciences, holds a slide with a moon rock sample that contains water. The water was found in the mineral apatite, which he and his team were able to identify in the sample. (Photo by Olivia Bartlett Drake)
Jim Greenwood, research assistant professor of earth and environmental sciences, holds a slide with a moon rock sample that contains water. The water was found in the mineral apatite, which he and his team were able to identify in the sample. (Photo by Olivia Bartlett Drake)

Soon after the Apollo spaceflights to the moon, experts examined the rocks brought back by the astronauts and declared with certainty that the moon was a dry, waterless place.

Forty years later, James Greenwood begs to differ. Not only does he have proof, his findings strongly suggest that some of the lunar water he found is not indigenous to the moon or earth but appears to have originated from somewhere else in space.

Greenwood, research associate professor, visiting assistant professor, Earth and Environmental Sciences, pioneered a new method of analyzing the rocks using a combination of light, electron and ion-beam microscopes. He and his international team of planetary geologists and geochemists, announced their findings at the 41st Annual Lunar and Planetary Science Conference in Houston, Texas, in March.

It was a discovery almost didn’t happen, however. In fact, the only reason Greenwood found proof of water on the moon was because he was looking at a rock from Mars.

“I was in a lab at Hokkaido University in Sapporo, Japan, using an ion microscope to measure water in Martian meteorites,” Greenwood, who is a planetary geochemist, says. “We had pioneered this new technique to use two-dimensional ion imaging and were looking at this mineral in the meteorites called ‘apatite,’ which is a common phosphate mineral and holds water. Our analyses had been very good, probably better than ever before. So I thought, ‘What if we used this technique on moon rocks?’”

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Greenwood thought of moon rocks because a 2008 study from Brown University had found possible evidence of water in volcanic moon rocks. However, the study had been problematic and its results disputed. Still, Greenwood was intrigued that the possibility of water in the lunar rock samples had not been thoroughly vetted.

“The rocks were all declared devoid of water when they were first analyzed 40 years ago,” he said. “But I thought our new technique held some promise.”

Greenwood’s technique and the advanced instruments he gained access to, made it possible for him and the other scientists on his team to analyze the sample’s chemical composition over areas as small as 5 x 5 microns.

“In the past, they had actually ground up the analyzed samples. This created conditions that put the chemical analysis out of context,” he says. “Our method let us look at the samples as they are, in situ.”

The hardest part was getting permission to examine a sample. Less than 900 rocks were brought back from all the Apollo missions combined. Access is strictly limited.

It took several months, but Greenwood was able to get a few samples to analyze. The first were from the lunar highlands, which he thought might hold promise. But no water-holding apatite was found. Then he gained access to a sliver of rock brought back from the southwestern edge of the Mare Tranquillitatis – the “Sea of Tranquility” – where Apollo 11 had set down in 1969.

“So there we were in the lab at about 3 a.m. and the first sample we looked at, boom, there it was. Water. At first we couldn’t believe it. But we double-checked and we were just blown away. It was clearly there.”

The apatite, which is the same mineral that teeth are made of, was rife with water molecules. However, as Greenwood and his colleagues continued to analyze the samples they found that the water contained in the rocks was not from the earth or the moon.

“It was consistent in the water that comes from comets,” Greenwood says.

How could he tell? Water molecules found on earth – and those indigenous to the moon, since it was once part of the earth – contain a specific ratio of hydrogen to deuterium, which scientists use as a standard. The water Greenwood has found in some of the lunar samples has nearly twice the deuterium.

“The only things that falls into this range with any consistency are comets,” Greenwood says.

He adds that comets have long been known to hold frozen water and that perhaps as much as 10% of the earth’s water had come from comets, as well.

Microscopic water in minerals inside moon rocks is a tremendous find, but in a practical sense it does not open the door to, say, astronauts extracting this water to use on a lunar base or colony. Greenwood says that process would be too expensive and energy-exclusive with current methods. However, his discovery does open up another possibility.

“The level of water we found in the samples are consistent with the amount of water one would find from the mantle in the earth,” he says. “So there may be a reservoir of water within the mantle of the moon. Somewhat like groundwater here on earth.”

How far within the mantle, how deep below the surface is another challenge for another completely different type of study.

But Greenwood and his team have confirmed what many people have wondered for centuries, perhaps millennia. There is water on the moon.