Tag Archive for planetary

Study by Redfield, Johnson ’11 Published in Astrophysical Journal, New Scientist

Seth Redfield, associate professor of astronomy, and Marshall Johnson ’11 are the co-authors of an article titled “The Interstellar Medium in the Kepler Search Volume,” published in The Astrophysical Journal, Vol. 802, No. 2, July 2015. The article highlights ways scientists are studying the gas and dust in the galaxy near where the Kepler Space Telescope is discovering exoplanets.

“Stars, with planets, can interact with the gas surrounding them in interesting ways, like bubbles in a drink, where each of the bubbles is an individual star (perhaps with planets) and the drink is the ‘interstellar medium’, the gas in between the stars,” Redfield explained.

In addition, The New Scientist published an article on Aug. 6 titled, “Distant worlds could be sheltering in a bubble around their star,” which focuses on the authors’ Astrophysical Journal study. It reads:

Distant planets may be swaddled in a protective bubble of magnetism and charged particles, courtesy of their parent star. The first study to scrutinize these so-called astrospheres shows that some exoplanets are more well shielded than Earth, others not so lucky – and that their protection can be fickle.

Within our solar system, the sun’s wind of charged particles and radiation forms a bubble called the heliosphere, which repels cosmic rays that can affect Earth’s weather, eat away at the ozone layer and damage DNA. Likewise, astrospheres guard faraway worlds from the ravages of the cosmos, says Marshall C. Johnson, an astronomer at the University of Texas in Austin.

An astrosphere’s size is determined partly by the strength of the star’s winds, and partly by the surrounding interstellar medium of gas and dust. The star’s velocity through the galaxy also has an effect.

“It’s just like if you are driving and you stick your hand out the window. You will experience higher pressure on your hand when you are driving fast than when you are driving slowly,” Johnson says. “If there is a greater relative velocity between the star and the interstellar medium, there will be a greater pressure exerted on the astrosphere.”

Johnson is working on his PhD in astronomy at the University of Texas in Austin. Marshall and Redfield had gone together in 2010-11 to observe at the McDonald Observatory in west Texas, and this project grew out of this work.

Another co-author on the paper, Adam Jensen, was a postdoctoral researcher at Wesleyan between 2010-2013 and was funded by the National Science Foundation.

Bow Shock Study by Redfield, Cauley Published in Astrophysical Journal

Seth Redfield, associate professor of astronomy, and Wilson Cauley, postdoctoral researcher in astronomy, led the effort on a paper titled “Optical hydrogen absorption consistent with a thin bow shock leading the hot Jupiter HD 189733b” accepted for publication in The Astrophysical Journal.

Wilson Cauley, postdoctoral researcher in astronomy, created a animation that shows the transit of bow shock material as it crosses a stellar disk, and the absorption values the model predicts. Cauley's study demonstrates an exciting path forward in attempting to measure exoplanet magnetic fields. 

Wilson Cauley, postdoctoral researcher in astronomy, created a animation that shows the transit of bow shock material as it crosses a stellar disk, and the absorption values the model predicts. Cauley’s study demonstrates an exciting path forward in attempting to measure exoplanet magnetic fields.

Bow shocks are ubiquitous astrophysical phenomena resulting from the supersonic passage of an object through a gas. In this paper, the authors present a robust detection of a time-resolved pre-transit, as well as in-transit, absorption signature around the hot Jupiter exoplanet HD 189733b using high spectral resolution observations of several hydrogen lines.

Better knowledge of exoplanet magnetic field strengths is crucial to understanding the role these fields play in planetary evolution and the potential development of life on planets in the habitable zone.

Cauley’s research is funded at Wesleyan through the National Science Foundation to study the extended atmospheres of exoplanets. For more information and to view a animation that summarizes the paper’s results, visit Cauley’s website.

In addition, Redfield and Cauley will present results from an observation made at the largest telescopes in the world, the Keck Telescope in Hawaii, during the International Astronomical Union General Assembly in August.

 

Graduate Student Factor Studies Planet Formation Around a Young Star

Sam Factor, a graduate student in astronomy, at the Submillimeter Array, located on Mauna Kea in Hawai'i in March 2015.

Sam Factor, a graduate student in astronomy, at the Submillimeter Array, located on Mauna Kea in Hawai’i in March 2015.

#THISISWHY
In this News @ Wesleyan story, we speak with Sam Factor ’14, a graduate student in astronomy.

Q: Sam, congratulations on completing your master’s thesis in astronomy! We understand you took your first astronomy class in the fall of your senior year at Wesleyan. What was your undergraduate major and how did your late-developing interest in astronomy come about?

A: Thank you very much! As an undergrad, I majored in physics and computer science. During the fall of my senior year I took Introductory Astronomy (ASTR 155). I signed up for the course mainly because I wanted an interesting and relatively easy course to fill out my schedule. I had been interested in astronomy since I was very young, but had never taken a formal class. I absolutely loved the class and decided to apply to the BA/MA program.

Q: How and when did you decide to stay on at Wesleyan to pursue a master’s degree in astronomy?

A: I actually decided to apply to the BA/MA program only a few weeks before the application was due!

Seager Delivers Sturm Memorial Lecture

On April 29, Sara Seager, Class of 1941 Professor of Planetary Science and Physics at the Massachusetts Institute of Technology, spoke on “The Search for Earth 2.0″ at the annual Sturm Memorial Lecture. (Photos by Dat Vu ’15)

Seager is a pioneer in the field of exoplanets, specifically in characterizing the atmospheres and searching for life on those distant worlds. Her talk addressed the age-old question: "Are we alone?"

Seager is a pioneer in the field of exoplanets, specifically in characterizing the atmospheres and searching for life on those distant worlds. Her talk addressed the age-old question: “Are we alone?”

Astronomy Department Awarded Grants for Research

Seth Redfield, astronomy professor of astronomy, campus director of the NASA CT Space Grant Consortium, reports that several students and faculty have recently been awarded grants for their research in astronomy.  Photo c/o Redfield

Seth Redfield, assistant professor of astronomy, campus director of the NASA CT Space Grant Consortium, reports that several students and faculty have recently been awarded grants for their research in astronomy. (Photo c/o Redfield)

Several Wesleyan students and faculty were recently awarded grants for research by NASA’s Connecticut Space Grant Program. Seth Redfield, associate professor of astronomy and campus director of NASA’s CT Space Grant Consortium, was excited about the number of winners.

“I was thrilled to see how successful Wesleyan was this year in getting grants through NASA’s CT Space Grant program,” wrote Redfield. “It demonstrates the diversity and quality of work we do that is aligned with NASA’s mission.”

“The grants this year support undergraduate, graduate, and faculty research, as well as special events organized by faculty at Wesleyan to promote exposure and career development in STEM fields,” explained Redfield.

Students, Faculty, Alumni Attend Planetary Science Conference in Texas

Students, faculty and alumni involved in planetary science attended the 46th Lunar and Planetary Science Conference March 16-20 in Houston, Texas.

Jim Greenwood, assistant professor earth and environmental sciences, gave a talk titled “urCl-KREEP? Cl-rich glasses in KREEP basalts 15382 and 15386 and their implications for lunar geochemistry.” Martha Gilmore, chair and professor of earth and environmental sciences and the George I. Seney Professor of Geology, met with the Venus Exploration Analysis Group as a member of its Executive Committee.

Jack Singer ’15 and Lisa Korn MA ’15 presented posters.

Several Wesleyan alumni also made presentations at the conference including James Dottin ’13 (E&ES), now a PhD student at the University of Maryland; Tanya Harrison MA ’08 (E&ES), now a PhD student at the University of Western Ontario; Ann Ollila MA ’08 (E&ES), now at Chevron; Nina Lanza MA ’06 (E&ES), now a scientist at Los Alamos National Lab; Bob Nelson MA ’69 (astronomy), senior scientist at Planetary Science Institute; Ian Garrick-Bethell ’02 (physics), assistant professor at the University of California – Santa Cruz.

Jack Singer ’15 presented a poster titled "High fluorine and chlorine in a chromite-hosted melt inclusion from Apollo 12 olivine basalt 12035.” He was supported by NASA Connecticut Space Grant and is the McKenna Scholar in E&ES. Jim Greenwood is his advisor.

Jack Singer ’15 presented a poster titled “High fluorine and chlorine in a chromite-hosted melt inclusion from Apollo 12 olivine basalt 12035.” He was supported by NASA Connecticut Space Grant and is the McKenna Scholar in E&ES. Singer’s advisor is Jim Greenwood, assistant professor earth and environmental sciences.

Lisa Korn, MA ’15 presented a poster titled "Possible Carbonate Minerals within an Unnamed Gulled Crater in Eridania Basin, Mars.”  She was supported by NASA Connecticut Space Grant and the E&ES Foye Fund. Scott Murchie, the Principal Investigator of the instrument whose data she uses (the CRISM spectrometer in orbit at Mars) showed her work to NASA as an example of the important new discoveries being made with the instrument. Korn's advisor is Marty Gilmore, chair and professor of earth and environmental sciences and the George I. Seney Professor of Geology.

Lisa Korn MA ’15 presented a poster titled “Possible Carbonate Minerals within an Unnamed Gullied Crater in Eridania Basin, Mars.” She was supported by NASA Connecticut Space Grant and the E&ES Foye Fund. Scott Murchie, the Principal Investigator of the instrument whose data she uses (the CRISM spectrometer in orbit at Mars) showed her work to NASA as an example of the important new discoveries being made with the instrument. Korn’s advisor is Martha Gilmore, chair and professor of earth and environmental sciences and the George I. Seney Professor of Geology.

E&ES major  James Dottin ’13 met Marty Gilmore at the conference.

E&ES major James Dottin ’13 met Martha Gilmore at the conference.

Astronomy Department Hosts Public Stargazing, Space Discovery Presentations

The Van Vleck Observatory on Foss Hill.

The Van Vleck Observatory on Foss Hill.

Beginning Feb. 4, Wesleyan’s Van Vleck Observatory will open to the public every Wednesday night, rain or shine, for presentations by faculty and students on the latest space-related discoveries, as well as a chance for everyone to view the sky through a telescope, weather permitting.

The program will start at 8 p.m. on Wednesdays. Presentations are intended to be accessible to visitors of all ages, although aimed primarily at high school level and above.

Paper by Gilmore, Harner MA ’13 Says Mars May Host Hydrous Carbonate Minerals

Martha Gilmore, the George I. Seney Professor of Geology, and her former graduate student Patrick Harner MA ’13 are the co-authors of a paper titled “Visible–near infrared spectra of hydrous carbonates, with implications for the detection of carbonates in hyperspectral data of Mars,” published in Icarus, Vol. 250, pages 204-214, April 2015.

The paper suggests that hydrous carbonate minerals might be relevant on Mars.

“We bought and made these unusual minerals in my lab and then took spectra of them to simulate what Mars orbiters might see. Carbonate minerals form in water on Earth (e.g., limestones), and are predicted for Mars, but to date are uncommon on Mars,” Gilmore explained. “We suggest this may be because Mars may host hydrous carbonates which look very different than the anhydrous carbonates everyone is looking for in the data.”

Gilmore also is chair and professor of earth and environmental sciences.

NASA Supports Greenwood’s Extraterrestrial Materials Research

James “Jim” Greenwood

Jim Greenwood

Jim Greenwood, assistant professor of earth and environmental sciences, was awarded a Faculty Seed Research Grant from the Connecticut Space Grant Consortium, supported by NASA. The honor comes with a $6,000 award.

Greenwood will use the grant to support his research on “D/H of ‘Dry’ Extraterrestrial Materials.”

Understanding the distribution, delivery, and processing of volatiles in the solar system is of fundamental interest to planetary science. Volatiles influence a number of important properties of planetary bodies, such as the cooling, differentiation, volcanism, tectonism, climate, hydrosphere/atmospheres and especially habitability.

Greenwood will use the award to develop a new state-of-the-art inlet system for the measurement of hydrogen and water and their hydrogen isotope composition in nominally anhydrous extraterrestrial materials. This inlet system will work in conjunction with the Wesleyan Hydrogen Isotope Mass Spectrometer, a Thermo Delta Advantage isotope ratio mass spectrometer installed in August 2014.

With the new system in place by the end of the project period, Greenwood and fellow researchers will be in position to measure hydrogen and water in two Apollo mare basalt rock samples.

“This will increase sensitivity for water by 250x our current measurement,” Greenwood said. “The added capability will allow us to make new and exciting measurements of volatiles in important planetary materials, such as these lunar rock samples.”

Read past News @ Wesleyan stories on Greenwood here.

Scholarship Helps Lieman-Sifry ’15 Study Gas Planet Formation

Jesse Lieman-Sifry '15 visited the Sub Millimeter Array in Hawaii this summer to help observe, learn about how radio astronomy data is collected, and see the array of antennas up close. Lieman-Sifry recently received a $5,000 Undergraduate Directed Campus Scholarship from the Connecticut Space Grant Consortium to support his ongoing research on gas planet formation.

Jesse Lieman-Sifry ’15 visited the Sub Millimeter Array in Hawaii this summer to help observe, learn about how radio astronomy data is collected, and see the array of antennas up close. Lieman-Sifry recently received a $5,000 Undergraduate Directed Campus Scholarship from the Connecticut Space Grant Consortium to support his ongoing research on gas planet formation.

 #THISISWHY

For the past year and a half, Jesse Lieman-Sifry ’15, an astronomy and physics double major, has focused his undergraduate research on understanding the formation of gas planets. This month, Lieman-Sifry received a $5,000 Undergraduate Directed Campus Scholarship from the Connecticut Space Grant Consortium, funded by NASA. The award will be applied to his financial aid package and support his ongoing research in the Astronomy Department.

Jesse Lieman-Sifry uses data to model the dust and gas on a specific star system called 49 Ceti.

Jesse Lieman-Sifry uses data to model the dust and gas on a specific star system called 49 Ceti. 49 Ceti is visible to the naked eye.

Planets form in disks of gas and dust left over from the formation of a star. For gas planets, such as Jupiter, Saturn, Uranus and Neptune, a massive rocky core must solidify before accumulation of gas can begin.

“In the 10 million years we assume it takes this rocky core to form, most of the gas has been blown away by the energy from the hot central star. This would suggest that it is very hard to form gas planets, as the timeline for these processes don’t line up,” Lieman-Sifry explained. “Something about this picture isn’t quite right though, as the planet-hunting Kepler mission has revealed that gas planets are actually very common around other stars in the Milky Way.”

Lieman-Sifry is working with high-resolution data collected by the Atacama Large Millimeter Array (ALMA) in Chile. The data, provided from radio interferometers, 

Hughes Finds Magnetic Fields in Stardust; Study Published in Nature

Assistant professor of Astronomy Meredith Hughes and eight colleagues have found evidence of magnetic fields in stardust – an indication that magnetic fields are important in the process of planetary system formation, according to a new paper in the journal Nature.

The discovery is another step in work by Hughes and other astronomers to understand how celestial bodies are formed. It is known that magnetic fields in the “accretion disks” of stars play a dominant role in the star formation process.

Meredith Hughes

Meredith Hughes

Using data from an observatory near Bishop, Calf., Hughes and her colleagues were able to spot signs of magnetic fields in the dust of the disk of a star about 300 light years away. While magnetic fields have been detected in regions that represent the very earliest stages of star formation (the so-called Class 0 and Class I stages), this is the first time they have been seen around a star with an older age closer to when we believe planetary systems form.

“This is an important result,” Hughes said. “It’s the first time that we’ve seen magnetic fields this late in the process of star and planet formation. And like any good scientific result, when you find something new it opens up whole new sets of questions we can ask.”

In fact, Hughes said the astronomers did not expect the results they got. “I honestly didn’t think it was going to work – we had been trying so long with Class II sources and hadn’t found anything,” she said. “But I thought, we might as well try this last source that is just a little younger than most Class II sources. You want to try everything you can – but it was really a surprise when it worked.”

The paper, “Spatially resolved magnetic field structure in the disk of a T Tauri star,” was published Oct. 22. Nature is the world’s most highly-cited interdisciplinary science publication. The 145-year-old journal is published weekly.

Solar Storms a Wake-Up Call, Redfield Says

solar_storm_2012 (3)

This NASA image shows a solar storm in early 2012.

A July NASA report that a huge solar storm narrowly missed Earth in 2012 – avoiding catastrophic damage to energy, transportation and communications systems – has caused a media stir and some worry among Earthlings.

What’s more, other recent reports say that Earth is overdue for a devastating storm of the kind known as a “Carrington event” after an 1859 storm that disrupted telegraph signals and caused other damage in a still-nascent industrial world. Named for 19th-century English astronomer Richard Carrington, it was the largest of its kind on record. A similar event now, in a world dependent on digital communications and electrical energy, would cause widespread, long-lasting power outages and disrupt transportation and communications planet-wide. Eric Mack, a science blogger for Forbes, referred facetiously to a reversion to “Amish-style” civilization.

Seth Redfield, assistant professor of astronomy, says the recent near-miss isn’t a cause for worldwide freakout, but should be a wake-up call; while a catastrophic solar storm may be several generations away, “it’s going to happen,” and scientists should be working on ways to better predict the event.

“I think it’s really important for us to understand what’s going on and have some good perspective on that because if we don’t prepare for it, we’re going to suffer the consequences,” he said. “We don’t need a Manhattan-style project and (to) devote 10 percent of our GDP to this one. But we do need to pay attention.”