Tag Archive for Redfield

Observational Cosmologist Delivers Sturm Lecture

On April 3, Daniel Eisenstein, a observational cosmologist and a professor at Harvard University, spoke on "Mapping the Universe with the Sloan Digital Sky Survey" during the annual Sturm Memorial Lecture. In memory of Kenneth E. Sturm from the Class of 1940, this annual event is open the entire Wesleyan community and features a presentation from an astronomer that is outstanding in his/her field and is able to communicate the excitement of science to a lay audience.

On April 3, Daniel Eisenstein, a observational cosmologist and a professor at Harvard University, spoke on “Mapping the Universe with the Sloan Digital Sky Survey” during the annual Sturm Memorial Lecture. In memory of Kenneth E. Sturm from the Class of 1940, this annual event is open the entire Wesleyan community and features a presentation from an astronomer that is outstanding in his/her field and is able to communicate the excitement of science to a lay audience.

Research by Redfield, Zachary ’17 Using Hubble, Voyager Probes Widely Reported

Astronomy student Julia Zachary '17 presented research at a press conference at the American Astronomical Society's 229th annual meeting on Jan. 6. (Photo by © CorporateEventImages/Todd Buchanan 2017)

Astronomy student Julia Zachary ’17 presented research at a press conference at the American Astronomical Society’s 229th annual meeting on Jan. 6. (Photo by © CorporateEventImages/Todd Buchanan)

Wesleyan Associate Professor of Astronomy Seth Redfield and astronomy student Julia Zachary ’17 recently reported at the 229th meeting of the American Astronomical Society on their research using data from the Hubble Space Telescope combined with two Voyager spacecraft probes, both very long-lived and successful NASA missions. The findings were shared in dozens of news outlets from the U.S. to India to Afghanistan.

According to Nature.com, “The work is a rare marriage of two of the most famous space missions — and an unprecedented glimpse at the realm between the stars.”

“If the Voyager spacecraft and the Google Street View car are going around your neighborhood taking pictures on the street, then Hubble is providing the overview, the road map for the Voyagers on their trip through interstellar space,” Zachary said at a press conference held Jan. 6.

Astronomers have used instruments such as Hubble to obtain indirect measurements of the material in interstellar space. But the Voyager probes are giving them a direct taste of this mysterious environment, sending back data on the electron density of their surroundings. “As an astronomer, I’m not used to having measurements from the place I’m observing,” Redfield said.

SpaceDaily.com reports: “A preliminary analysis of the Hubble observations reveals a rich, complex interstellar ecology, containing multiple clouds of hydrogen laced with other elements. Hubble data, combined with the Voyagers, have also provided new insights into how our sun travels through interstellar space.”

“This is a great opportunity to compare data from in situ measurements of the space environment by the Voyager spacecraft and telescopic measurements by Hubble,” said study leader Seth Redfield of Wesleyan University in Middletown, Connecticut.

“The Voyagers are sampling tiny regions as they plow through space at roughly 38,000 miles per hour. But we have no idea if these small areas are typical or rare. The Hubble observations give us a broader view because the telescope is looking along a longer and wider path. So Hubble gives context to what each Voyager is passing through.”

Read more at Astronomy.comThe Indian ExpressEarthSky.org and International Business Times. See photos of Zachary at the press conference on the American Astronomical Society’s website. A press release can be found on HubbleSite.

Redfield also is associate professor of integrative sciences.

Four Students Awarded NASA Connecticut Space Grants

Grant recipient Rami Hamati '19, left, at a workshop sponsored last summer by the CT Space Grant on helicopters and other small aircraft.

Grant recipient Rami Hamati ’19, left, is pictured at a workshop sponsored last summer by the Connecticut Space Grant on helicopters and other small aircraft.

Four Wesleyan undergraduate students have received grants from NASA’s Connecticut Space Grant Consortium.

Astronomy major Hannah Fritze ’18 was awarded $5,000 for an Undergraduate Research Fellowship Grant titled, “Searching for Intermediate Mass Black Holes in Ultraluminous X-ray Binaries.” This grant will support her research this coming semester on black holes with Roy Kilgard, support astronomer and research associate professor of astronomy.

Avi Stein ’17, who is majoring in astronomy, was awarded $1,000 for a Student Travel Grant. He will be presenting his research on Venus—conducted with Martha Gilmore, the George I. Seney Professor of Geology, professor of earth and environmental sciences—at the 48th Lunar and Planetary Science Conference (LPSC) in March.

Rami Hamati ’19 and David Machado ’18 each received a $5,000 undergraduate scholarship. According to Seth Redfield, associate professor of astronomy, associate professor of integrative sciences, these scholarships are awarded to students who show promise as a major in a STEM field related to NASA’s mission.

Read about past recipients of Connecticut Space Grants here and here.

Redfield Speaks to Wesleyan Staff about Discovering Exoplanets

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On Oct. 31, Seth Redfield, associate professor of astronomy, spoke on “Blue Skies on Distant Worlds” during a special luncheon for staff in Daniel Family Commons. Redfield, whose research interests focus on exoplanets and their atmospheres, explained how astronomers can detect and measure planets outside of our solar system. In the same way Earth orbits around the sun, an exoplanet will circle around a star. For some planetary systems, from Earth, astronomers can view the the exoplanet passing directly in front of its host star once per orbit.

Van Vleck Observatory Celebrates Centennial with Exhibition, Event Series

Wesleyan’s iconic observatory dome was built to house the Van Vleck Refractor, used in research until the early 1990s. Photo by John Van Vlack.

Wesleyan’s iconic observatory dome was built to house the Van Vleck Refractor, used in research until the early 1990s. (Photo by John Van Vlack)

The building was named for Professor John Monroe Van Vleck, who taught mathematics and astronomy at Wesleyan from 1853 until his death in 1912.

The building was named for Professor John Monroe Van Vleck, who taught mathematics and astronomy at Wesleyan from 1853 until his death in 1912.

Wesleyan’s Van Vleck Observatory is celebrating its centennial this spring, with a series of events and an exhibition beginning in early May.

On May 6, the observatory’s library will reopen to the public with an exhibition on the history of astronomy at Van Vleck. Developed by a team of faculty, students, and staff, the exhibition will use the observatory’s extensive collection of scientific instruments, teaching materials, photographs, drawings, and correspondence to illustrate both the changes in astronomical research and teaching over the past century, and the observatory’s consistent mission of conducting instruction and research under the same roof. The exhibition will incorporate the history of science into Van Vleck’s existing public outreach programs through period lectures, demonstrations of historic artifacts, and gallery talks.

“The Millionaire” Mechanical Calculator. Useful for determining distances to stars, this late 19th-century calculator had high precision (eight significant figures) and is still in perfect working order. (Photo by John Van Vlack)

“The Millionaire” Mechanical Calculator. Useful for determining distances to stars, this late 19th century calculator had high precision (eight significant figures) and is still in perfect working order. (Photo by John Van Vlack)

The exhibition was spearheaded by Roy Kilgard, support astronomer and research associate professor of astronomy, Seth Redfield, associate professor of astronomy, associate professor of integrative sciences, Amrys Williams, visiting assistant professor of history, and Paul Erickson, associate professor of history, associate professor of environmental studies, associate professor of science in society.

More events are planned in the run-up to the exhibition opening. On May 1, the Wesleyan Orchestra will hold a concert featuring astronomically themed music, including John Cage’s Atlas Eclipticalis, which was composed using star charts from the Van Vleck Observatory library. On May 3, Special Collections & Archives will host an exhibition, “A Stellar Education: Astronomy at Wesleyan, 1831-1916.” Located on the first floor of Olin Library, the exhibition documents the study of astronomy at Wesleyan from the university’s opening through the construction of the Van Vleck Observatory. On May 4, the History Department is hosting David DeVorkin, senior curator at the National Air and Space Museum, who will give a talk situating Van Vleck in the history of American observatories.

Faculty, Students Win Research Support from NASA’s CT Space Grant Consortium

The Van Vleck Observatory on Foss Hill.

The Van Vleck Observatory on Foss Hill.

Two faculty members and three students have been awarded grants in the latest call for proposals from NASA’s Connecticut Space Grant Consortium.

Jim Greenwood, assistant professor of earth and environmental sciences, and Bill Herbst, the John Monroe Van Vleck Professor of Astronomy, professor of integrative sciences, were awarded $8,000 for a Faculty Collaboration Grant titled “Chondrule Formation Experiments.” This is to run high-temperature experiments on material that makes up meteorites in order to test a hypothesis that they put forward in a recent paper in Icarus this year.

Seth Redfield, associate professor of astronomy, associate professor of integrative sciences, was awarded $1,500 for a STEM Education Programming Grant

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.

 

7 Faculty Promoted, Awarded Tenure

In its most recent meeting, the Board of Trustees promoted seven faculty members.

The BOT conferred tenure on Lauren Caldwell, associate professor of classical studies; Stephen Collins, associate professor of film studies; Paul Erickson, associate professor of history; Matthew Garrett, associate professor of English; Brian Northrop, associate professor of chemistry; Julia Randall, associate professor of art; and Seth Redfield, associate professor of astronomy.

The promotions are effective July 1, 2015.

Brief descriptions of their areas of research and teaching appear below.

Lauren Caldwell
Caldwell’s research focuses on Roman social history, Roman law, and Greco-Roman medicine. Her recent book, Roman Girlhood and the Fashioning of Femininity (Cambridge University Press, 2014) investigates the social pressures

Redfield Speaks about Magnetic Polarity Flipping on WNPR

Seth Redfield

Seth Redfield

Seth Redfield, assistant professor of astronomy, spoke with Patrick Skahill and WNPR News on Nov. 15 about the sun flipping its magnetic polarity, which only happens every 11 years. While the change in polarity is not fully understood by scientists, the event is exciting “because this is kind of a probe into the internal workings of the sun, which is actually really hard for us to get a handle on,” according to Redfield.

This solar cycle, Cycle 24, has not been disruptive to satellites or the electric grid, which can react negatively to solar radiation. The sun’s northern hemisphere flipped earlier this summer and the southern hemisphere is poised to flip very soon.

Read the article online here.

NASA’s Astronomy Picture of the Day Features Redfield’s Interstellar Medium

"The Local Fluff" by Seth Redfield, assistant professor of astronomy.

“The Local Fluff” by Seth Redfield, assistant professor of astronomy.

On Sept. 24, NASA’s Astronomy Picture of the Day featured a figure that Assistant Professor of Astronomy Seth Redfield generated as part of his research on the interstellar medium, the gas and dust surrounding the Sun and other nearby stars. Each day, NASA features a different image or photograph of the universe, along with a brief explanation written by a professional astronomer.

The explanation of the figure states: “The stars are not alone. In the disk of our Milky Way Galaxy about 10 percent of visible matter is in the form of gas, called the interstellar medium (ISM). The ISM is not uniform, and shows patchiness even near our Sun. It can be quite difficult to detect the local ISM because it is so tenuous and emits so little light. This mostly hydrogen gas, however, absorbs some very specific colors that can be detected in the light of the nearest stars.

A working map of the local ISM within 20 light-years, based on ongoing observations and recent particle detections from the Earth-orbiting Interstellar Boundary Explorer satellite (IBEX), is shown above. These observations indicate that our Sun is moving through a Local Interstellar Cloud as this cloud flows outwards from the Scorpius-Centaurus Association star forming region.

Our Sun may exit the Local Cloud, also called the Local Fluff, during the next 10,000 years. Much remains unknown about the local ISM, including details of its distribution, its origin, and how it affects the Sun and the Earth. Unexpectedly, recent IBEX spacecraft measurements indicate that the direction from which neutral interstellar particles flow through our Solar System is changing.”