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  • richardmitnick 8:54 am on September 13, 2017 Permalink | Reply
    Tags: , , Binary star system AR Scorpii, , Notre Dame University   

    From Notre Dame: “A one-of-a-kind star found to change over decades” 

    Notre Dame bloc

    Notre Dame University

    September 12, 2017
    Jessica Sieff
    574-631-3933
    jsieff@nd.edu

    1
    AR Scorpii. No image credit

    Astronomers studying the unique binary star system AR Scorpii have discovered the brightness of the system has changed over the past decade. The new evidence lends support to an existing theory of how the unusual star emits energy. AR Scorpii consists of a rapidly spinning, magnetized white dwarf star that mysteriously interacts with its companion star. The system was recently found to more than double in brightness on timescales of minutes and hours, but research recently published in The Astrophysical Journal Letters found variability on a timescale of decades.

    Researchers at the University of Notre Dame analyzed data on the unique system from the Kepler Space Telescope’s K2 mission taken in 2014 before the star was known to be unusual.

    NASA/Kepler Telescope

    The data was then compared with archival sky survey images going back to 2004 to look for long-term changes in the light curve of AR Scorpii. The binary’s light curve is unique, in that it exhibits a spike in emission every two minutes as well as a major brightness variation over the approximately 3.5-hour orbital period of the two stars

    “One model of this system predicts long-term variations in the way the two stars interact. It was not known what the time scale of these changes might be — whether 20 to 200 years. By looking at the K2 and archival data, we were able to show that in addition to hourly changes in the system, there are variations occurring over decades,” said Peter Garnavich, professor and department chair of astrophysics and cosmology physics at Notre Dame.

    A white dwarf is a very dense remnant of a star like the sun. When a solar-like star runs out of energy, gravity compresses its core to about the size of the Earth but with a mass 300,000 times higher. A teaspoon-sized piece of a white dwarf would weigh about 15 tons. The compression of the star can also amplify its magnetic field strength and its spin rate.

    The unique system became famous in 2016 when researchers in England discovered that AR Scorpii, believed to be a mundane solitary star, was actually a rapidly varying binary. The system is remarkable as the white dwarf spins on its axis at an incredibly fast rate, causing flashes in luminosity every two minutes. The amplitude of the flashes varies over the 3.5-hour orbital period, something no other white dwarf binary system is known to do.

    “We found that back 12 years ago, AR Scorpii’s peak brightness came a bit later in its orbit than it does now,” said Colin Littlefield, research associate working with Garnavich. “This does not solve the mystery, but it is another piece to the puzzle that is AR Scorpii.”

    The team at Notre Dame has been observing the system with the Sarah L. Krizmanich Telescope at the University’s Jordan Hall of Science, and they plan to publish those results in an upcoming paper.

    Co-authors of the study include Notre Dame Naughton Fellow Mark Kennedy, Paul Callanan at University College Cork, Benjamin Shappee at Carnegie Observatories and Thomas Holoien at The Ohio State University.

    Research was funded in part by NASA.

    See the full article here .

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

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  • richardmitnick 7:36 pm on June 26, 2017 Permalink | Reply
    Tags: , Electromagnetic radiation [light], Hyperbolic metamaterials (HMMs), Molecular beam epitaxy, Nanoresonators, , Notre Dame University, , ,   

    From Notre Dame: “Notre Dame Researchers Open Path to New Generation of Optical Devices” 

    Notre Dame bloc

    Notre Dame University

    COLLEGE of ENGINEERING

    OFFICE of the PROVOST
    College of Engineering

    June 22, 2017
    Nina Welding

    1
    Sub-diffraction Confinement in All-semiconductor Hyperbolic Metamaterial Resonators was co-authored by graduate students Kaijun Feng and Galen Harden and Deborah L. Sivco, engineer-in-residence at MIRTHE+ Photonics Sensing Center, Princeton Univ.

    Cameras, telescopes and microscopes are everyday examples of optical devices that measure and manipulate electromagnetic radiation [light]. Being able to control the light in such devices provides the user with more information through a much better “picture” of what is occurring through the lens. The more information one can glean, the better the next generation of devices can become. Similarly, controlling light on small scales could lead to improved optical sources for applications that span health, homeland security and industry. This is what a team of researchers, led by Anthony Hoffman, assistant professor of electrical engineering and researcher in the University’s Center for Nano Science and Technology (NDnano), has been pursuing. Their findings were recently published in the June 19 issue of ACS Photonics.

    In fact, the team has fabricated and characterized sub-diffraction mid-infrared resonators using all-semiconductor hyperbolic metamaterials (HMMs) that confine light to extremely small volumes — thousands of times smaller than common materials.

    2
    The scanning electron microscope image here shows an array of 0.47 μm wide resonators with a 2.5 μm pitch. No image credit.

    HMMs combine the properties of metals, which are excellent conductors, and dielectrics, which are insulators, to realize artificial optical materials with properties that are very difficult, even impossible, to find naturally. These unusual properties may elucidate the quantum mechanical interactions between light and matter at the nanoscale while giving researchers a powerful tool to control and engineer these light-matter interactions for new optical devices and materials.

    Hoffman’s team engineered these desired properties in the HMMs by growing them via molecular beam epitaxy using III-V semiconductor materials routinely used for high-performance optoelectronic devices, such as lasers and detectors. Layers of Si-doped InGaAs and intrinsic AlInAs were placed on top of one another, with a single layer being 50 nm thick. The total thickness of the HMM was 1μm, about 100 times smaller than the width of a human hair.

    The nanoresonators were produced by Kaijun Feng, graduate student in the Department of Electrical Engineering, using state-of-the-art fabrication equipment in Notre Dame’s Nanofabrication Facility. The devices were then characterized in Hoffman’s laboratory using a variety of spectroscopic techniques.

    “What is particularly exciting about this work,” says Hoffman, “is that we have found a way to squeeze light into small volumes using a mature semiconductor technology. In addition to being able to employ these nanoresonators to generate mid-infrared light, we believe that these new sources could have significant application in the mid-infrared portion of the spectrum, which is used for optical sensing across areas such as medicine, environmental monitoring, industrial process control and defense. We are also excited about the possibility of utilizing these nanoresonators to study interactions between light and matter that previously have not been possible.”

    See the full article here .

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 1:56 pm on January 16, 2017 Permalink | Reply
    Tags: , , FO Aquarii, Notre Dame University, Sarah L. Krizmanich Telescope   

    From Notre Dame: “Notre Dame astrophysicists discover dimming of binary star’ 

    Notre Dame bloc

    Notre Dame University

    January 16, 2017
    Brian Wallheimer

    A team of University of Notre Dame astrophysicists led by Peter Garnavich, professor of physics, has observed the unexplained fading of an interacting binary star, one of the first discoveries using the University’s Sarah L. Krizmanich Telescope.

    Notre Dame Rooftop Sarah L Krizmanich  Telescope
    Notre Dame Rooftop Sarah L Krizmanich  Telescope Interior
    Notre Dame Rooftop Sarah L Krizmanich Telescope

    The binary star, FO Aquarii, located in the Milky Way galaxy and Aquarius constellation about 500 light-years from Earth, consists of a white dwarf and a companion star donating gas to the compact dwarf, a type of binary system known as an intermediate polar. The system is bright enough to be observed with small telescopes. Garnavich and his team started studying FO Aquarii, known as “king of the intermediate polars,” a few years ago when NASA’s Kepler Telescope was pointed toward it for three months. The star rotates every 20 minutes, and Garnavich wanted to investigate whether the period was changing.

    “I asked Erin Aadland, an REU student, to precisely measure the spin rate of a white dwarf. Does it speed up or slow down?” he said. “We can do that by looking at the interval between flashes from the star just like we use the ticks in a clock to tell time. The star turned out to have other plans for the summer.”

    Intermediate polars are interesting binary systems because the low-density star drops gas toward the compact dwarf, which catches the matter using its strong magnetic field and funnels it to the surface, a process called accretion. The gas emits X-rays and optical light as it falls, and we see regular light variations as the stars orbit and spin. Graduate student Mark Kennedy studied the light variations in detail during the three months the Kepler Space Telescope was pointing at FO Aquarii in 2014. Kennedy is a Naughton Fellow from University College, Cork, in Ireland who spent a year and a half working at Notre Dame on interacting binary stars. “Kepler observed FO Aquarii every minute for three months, and Mark’s analysis of the data made us think we knew all we could know about this star,” Garnavich said.

    Once Kepler was pointed in a new direction, Garnavich and his group used the Krizmanich Telescope to continue the study.

    “Just after the star came around the sun last year, we started looking at it through the Krizmanich Telescope, and we were shocked to see it was seven times fainter than it had ever been before,” said Colin Littlefield, a member of the Garnavich lab. “The dimming is a sign that the donating star stopped sending matter to the compact dwarf, and it’s unclear why. Although the star is becoming brighter again, the recovery to normal brightness has been slow, taking over six months to get back to where it was when Kepler observed.”

    “Normally, the light that we’d see would come from the accretion energy, and it got a lot weaker when the gas flow stopped. We are now following the recovery over months,” Garnavich said.

    One theory is that a star spot, a cool region on the companion, rotated into just the right position to disrupt the flow of hydrogen from the donating star. But that doesn’t explain why the star hasn’t then recovered as quickly as it dimmed.

    Garnavich and his team also found that the light variations of FO Aquarii became very complex during its low state. The low gas transfer rate had meant the dominant, 20-minute signal had faded and allowed other periods to show up. Instead of a steady 20 minutes between flashes, sometimes there was an 11-minute signal and at other times a 21-minute pulse.

    “We had never seen anything like this before,” Garnavich said. “For two hours, it would flash quickly and then the next two hours it would pulse more slowly.”

    The Sarah L. Krizmanich Telescope, installed on the roof of the Jordan Hall of Science in 2013, features a 0.8-meter (32-inch diameter) mirror. It provides undergraduate and graduate students cutting-edge technology for research and is used to test new instrumentation developed in the Department of Physics at Notre Dame.

    The Notre Dame team that studied FO Aquarii included Littlefield, Aadland and Kennedy. The team’s findings have been published in the Astrophysical Journal. Institutions that contributed to the work include The Ohio State University, University Cote d’Azur (France), University de Liege (Belgium) and the American Association of Variable Star Observers (AAVSO)

    See the full article here .

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 12:08 pm on January 5, 2017 Permalink | Reply
    Tags: , , , , , Notre Dame University, Super-massive black hole, Vinicius Placco   

    From Notre Dame: “Notre Dame astrophysicist confirms source of galaxy collision” 

    Notre Dame bloc

    Notre Dame University

    January 05, 2017
    Brian Wallheimer

    1
    Vinicius Placco. No image credit

    Vinicius Placco, a research assistant professor of astrophysics at Notre Dame, collaborated with colleagues at the Harvard-Smithsonian Center for Astrophysics [CfA] to confirm that a massive amount of energy seen 2 billion light years from Earth stems from the collision of two galaxy clusters at the site of a giant black hole.

    Placco’s work is published today in the inaugural edition of Nature Astronomy. The paper’s findings detail matter ejected by a black hole being swept into the merger of two galaxy clusters.

    The black hole in one galaxy cluster shoots away much of the gas flowing toward it. The fast-moving particles receive a boost of energy from the galaxy cluster collision, creating shock waves.

    Placco was able to measure the spectrum of light coming from the galaxy harboring the super-massive black hole, to prove that it belongs to the galaxy cluster pair Abell 3411-12. That was used with other data collected from NASA’s Chandra X-Ray Observatory, the Giant Metrewave Radio Telescope [GMRT] in India, and the Keck Observatory and Japan’s Subaru telescope, both on Mauna Kea, Hawaii.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    GMRT Radio Telescope, located near Pune, India
    GMRT Radio Telescope, located near Pune, India

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory, Mauna Kea, Hawaii, USA

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA
    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    Placco and Rafael Santucci, a graduate student at Universidade de São Paulo, Brazil, were awarded time on the Southern Astrophysical Research (SOAR) Telescope in Chile and were making remote observations from South Bend and São Paulo. A friend from his undergraduate years at Universidade de São Paulo, Felipe Andrade-Santos, who now is a post-doctoral research fellow at Harvard, asked Placco if he would use some of his time on the telescope to observe a galaxy in the direction of the Abell 3411 and Abell 3412 galaxy clusters.

    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón - IV Región - Chile, at 2,700 meters (8,775 feet)
    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón – IV Región – Chile, at 2,700 meters

    “It can take six months to a year to get time on the telescope, and this would delay the research considerably. Since we were at the telescope, we could help the Harvard team confirm what they were expecting to see,” Placco said. “We were in the right place at the right time with the right expertise.”

    Placco said it is satisfying to know that he was able to help as part of one piece of a puzzle that connected researchers on several continents and countries.

    “This is what makes science interesting and appealing,” Placco said. “All of these collaborators, even though they are not in the same place all the time, they know they can count on each other and work together.”

    See the full article here .

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 11:13 am on December 8, 2016 Permalink | Reply
    Tags: , , Notre Dame University, Second-generation stars identified giving clues about their predecessors   

    From Notre Dame: “Second-generation stars identified, giving clues about their predecessors” 

    Notre Dame bloc

    Notre Dame University

    December 06, 2016
    Brian Wallheimer

    1
    The figure shows a sub-population of ancient stars, called carbon-enhanced metal-poor stars. The unusual chemical compositions of these stars provides clues to their birth environments. A( C) is the absolute amount of carbon, while the horizontal axis represents the ratio of iron, relative to hydrogen, compared with the same ratio in the Sun.

    University of Notre Dame astronomers have identified what they believe to be the second generation of stars, shedding light on the nature of the universe’s first stars.

    A subclass of carbon-enhanced metal-poor (CEMP) stars, the so-called CEMP-no stars, are ancient stars that have large amounts of carbon but little of the heavy metals (such as iron) common to later-generation stars. Massive first-generation stars made up of pure hydrogen and helium produced and ejected heavier elements by stellar winds during their lifetimes or when they exploded as supernovae. Those metals — anything heavier than helium, in astronomical parlance — polluted the nearby gas clouds from which new stars formed.

    Jinmi Yoon, a postdoctoral research associate in the Department of Physics; Timothy Beers, the Notre Dame Chair in Astrophysics; and Vinicius Placco, a research professor at Notre Dame, along with their collaborators, show in findings published in the Astrophysical Journal this week that the lowest metallicity stars, the most chemically primitive, include large fractions of CEMP stars. The CEMP-no stars, which are also rich in nitrogen and oxygen, are likely the stars born out of hydrogen and helium gas clouds that were polluted by the elements produced by the universe’s first stars.

    “The CEMP-no stars we see today, at least many of them, were born shortly after the Big Bang, 13.5 billion years ago, out of almost completely unpolluted material,” Yoon says. “These stars, located in the halo system of our galaxy, are true second-generation stars — born out of the nucleosynthesis products of the very first stars.”

    Beers says it’s unlikely that any of the universe’s first stars still exist, but much can be learned about them from detailed studies of the next generation of stars.

    “We’re analyzing the chemical products of the very first stars by looking at what was locked up by the second-generation stars,” Beers says. “We can use this information to tell the story of how the first elements were formed, and determine the distribution of the masses of those first stars. If we know how their masses were distributed, we can model the process of how the first stars formed and evolved from the very beginning.”

    The authors used high-resolution spectroscopic data gathered by many astronomers to measure the chemical compositions of about 300 stars in the halo of the Milky Way. More and heavier elements form as later generations of stars continue to contribute additional metals, they say. As new generations of stars are born, they incorporate the metals produced by prior generations. Hence, the more heavy metals a star contains, the more recently it was born. Our sun, for example, is relatively young, with an age of only 4.5 billion years.

    A companion paper, titled “Observational constraints on first-star nucleosynthesis. II. Spectroscopy of an ultra metal-poor CEMP-no star,” of which Placco was the lead author, was also published in the same issue of the journal this week. The paper compares theoretical predictions for the chemical composition of zero-metallicity supernova models with a newly discovered CEMP-no star in the Milky Way galaxy.

    Contact: Timothy Beers, 574-631-4088, tbeers@nd.edu

    See the full article here .

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 5:45 pm on June 20, 2016 Permalink | Reply
    Tags: , Astrophysicists release new study of one of the first stars, , Notre Dame University   

    From Astronomy: “Astrophysicists release new study of one of the first stars” 

    Astronomy magazine

    Astronomy.com

    Notre Dame bloc

    June 20, 2016
    Marissa Gebhard, University of Notre Dame, Indiana

    1
    Artist’s impression of the first stars, 400 million years after the Big Bang. NASA/WMAP Science Team

    No one has yet observed the first stars that formed in the Milky Way. In all likelihood, they will never be directly observed, because the first stars are massive, ending their lives only a few millions years after their birth.

    But, astronomers can study those oldest stars by examining the elements these stars produced through nuclear fusion and the supernova explosions that mark the spectacular ends of their short lives.

    3
    Timothy Beers. No image credit

    Timothy Beers, the Notre Dame Chair in Astrophysics at the University of Notre Dame, is part of a team that has used the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope to study key regions of the ultraviolet (UV) spectrum of a star thought to have been enriched by elements from one of the first generation of stars. This star, named BD+44 493, is the brightest known second-generation star in the sky. While examining its UV spectrum, Beers and his team detected several elements that had never been seen before in such a star. Their findings were published Monday (June 20) in the Astrophysical Journal Letters.

    Beers and his team detected phosphorus and sulphur, which had never been seen previously, and zinc, which had only been seen in one such second-generation star. They compared the amounts of each element to model predictions to learn about the nature of one of the first stars.

    Their work is the first to use COS on the Hubble Space Telescope to study the elements in ancient stars. These never-before-seen products of one of the first stars reveal that the particular star that introduced these atoms into space was likely massive, probably more than 20 times more massive than our own Sun, and exploded as a relatively faint supernova.

    At present, only the Hubble Space Telescope can collect the UV spectra needed to study these elements in ancient stars. These results foreshadow the exciting possibility of studying dozens or even hundreds of these ancient stars with the next generation of UV spectrographs on space telescopes, like the High Definition Space Telescope now under consideration by NASA.

    Authors of the study are Ian U. Roederer at the University of Michigan, and Beers and Vinicius M. Placco at the University of Notre Dame. The paper is available online here: http://iopscience.iop.org/article/10.3847/2041-8205/824/2/L19.

    Contact: Timothy Beers, 574-631-4088, tbeers@nd.edu

    Originally published by Marissa Gebhard at news.nd.edu on June 20, 2016.

    See the full article here .

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  • richardmitnick 3:35 pm on June 8, 2016 Permalink | Reply
    Tags: , , Nicole L. Achee, Notre Dame University,   

    From Notre Dame: Women in Science “Entomologist Nicole L. Achee helps write gene drives report” 

    Notre Dame bloc

    Notre Dame University

    June 08, 2016
    William G. Gilroy

    1
    Nicole Achee

    University of Notre Dame medical entomologist Nicole L. Achee is a member of a committee convened to summarize the scientific discoveries related to gene drives and considerations for their responsible use. The National Institutes of Health (NIH) and the Foundation for the National Institutes of Health asked the National Academies of Sciences, Engineering and Medicine to convene the committee. The committee report, titled “Gene Drives on the Horizon: Advancing Science, Navigating Uncertainty and Aligning Research with Public Values,” was released Wednesday (June 8).

    Gene drives are systems (either existing in nature or human-made) that transfer genetic material from a parent organism to its offspring through sexual reproduction. The result of a gene drive is the preferential increase of a specific trait from one generation to the next, which therefore can spread throughout the population.

    “For example, a gene drive system could change the ability of a female mosquito to ‘smell’ a human and therefore succeed in ‘finding’ a person to bite,” Achee said. “Inheritance of this trait could potentially cause a reduction in that mosquito’s population over time because blood is needed by the females to develop eggs.”

    The report is intended to be used as a tool by the general public and professionals alike who are either interested in gene drives or directly involved with their evaluation, development and use. It is based on six core themes: values, science, phased testing, risk assessment, public engagement and governance of gene drives.

    Gene drive systems are being proposed to solve a number of problems. These include challenges in public health, agriculture and conservation.

    “Most research on gene drive systems to date has been focused on generating a basic understanding of their function and mechanisms for controlling or altering organisms that transmit infectious diseases to humans, such as mosquitoes that carry parasites causing malaria,” Achee said. “Other applications of gene drive systems range from the control of weeds that compete with cash crops to management of invasive species that threaten biodiversity of ecosystems.”

    Achee’s research focuses on preventing and controlling human diseases caused by arthropods, such as mosquitoes. She is research associate professor in Notre Dame’s Department of Biological Sciences and a faculty member of the University’s Eck Institute for Global Health. The National Academies of Science invited her to participate in the study based on her expertise in mosquito ecology, international field-based research and global health.

    See the full article here .

    Please help promote STEM in your local schools.

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 7:40 am on May 17, 2016 Permalink | Reply
    Tags: , , , Notre Dame University, Pontifical Catholic University of Chile (PUC)   

    From Notre Dame: “Notre Dame chemistry and biochemistry hosts faculty from Pontifical Catholic University of Chile” 

    Notre Dame bloc

    Notre Dame University

    May 16, 2016
    Brian Wallheimer

    1
    No image caption. No image credit.
    _________________________________________________________

    Seven members of the Pontifical Catholic University of Chile (PUC) visited Notre Dame last week to strengthen developing research partnerships and plan upcoming workshops in biochemistry and chemistry, the latest in a partnership between the universities started in 2013.

    Notre Dame and PUC signed a memorandum of understanding in 2013 that formalized research partnerships, as well as faculty and student exchange programs. Much of the work and collaborations have been possible through the Luksic Grants Program through Notre Dame International.

    “The department has fully embraced the opportunity to work with PUC Chile,” says Ken Henderson, chair of the Department of Chemistry and Biochemistry at Notre Dame. “The latest visit by PUC Chile faculty to Notre Dame demonstrates the enthusiasm for building this relationship.”

    Since the universities formally partnered, they have held joint graduate summer schools in Santiago, Chile, along with the University of Heidelberg, which Notre Dame entered into a similar agreement with in 2014. Last year, the three schools organized the Santander International Summer School on molecular catalysts in Chile, focused on fundamentals and developments in molecular catalysts. Students from Germany, France, Chile, Brazil, Spain, Switzerland and the United States attended.

    Notre Dame has hosted PUC graduate student research visits, and nine Notre Dame faculty have visited Chile over the past two years.

    The universities are working to develop a dual doctoral program over the next few months, and there will be a graduate workshop on X-ray crystallography and a joint symposium on drug discovery in Chile in the next academic year.

    See the full article here .

    Please help promote STEM in your local schools.

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 11:31 am on April 21, 2016 Permalink | Reply
    Tags: , , Notre Dame University   

    From Notre Dame: “Wind energy and plasma research” 

    Notre Dame bloc

    Notre Dame University

    April 19, 2016
    Brandi Klingerman

    As the world looks for new ways to diversify its energy supply and find renewable resources to power the earth’s growing energy consumption needs, new research from the University of Notre Dame has identified a potential way to make an existing renewable resource – wind energy – more efficient in power production.

    1
    Notre Dame White Field

    Thomas Corke, the Clark Chair Professor in Aerospace and Mechanical Engineering and founding director of the Notre Dame Institute for Flow Physics and Control (FlowPAC), along with a team of collaborative researchers, developed a new plasma actuator that can be used to make a more capable design for wind turbine airflow and control than previous systems. When applied to wind turbines, this actuator could increase the amount of energy that can be produced by up to 10 percent and significantly reduce the wind loads on the rotor blades, improving their longevity.

    The University of Notre Dame has recently licensed the plasma actuators, along with a set of improvements in flow control, as part of a patent portfolio. The portfolio includes active devices that reduce turbulent air and improve a turbine’s ability to capture energy from wind.

    The active devices utilize the actuator to affect wind as it moves over a wind turbine’s blade, thus modifying airflow to obtain flow improvement. The effect is a “virtual shaping” of the rotor blade. The advancement is cost-effective, as Aquanis, LLC – the company who has acquired the patent – predicts that the technology can be easily incorporated in new blade design and potentially adapted to existing turbines and that use of the device can pay for itself in less than two years.

    University of Notre Dame faculty who contributed to the development of these licensed technologies include Eric Jumper, professor of aerospace and mechanical engineering as well as the director of the Aero-Optics group; Robert Nelson, professor of aerospace and mechanical engineering; and Flint Thomas, professor of aerospace and mechanical engineering. Other contributing researchers include Carl Enloe and Thomas McLaughlin from the United States Air Force, as well as Alan Cain and Mehul Patel with the Innovative Technologies Applications Company.

    When speaking about his team’s work, Corke said, “I, along with an impressive group of Notre Dame engineers and other researchers, conducted research analyzing wind turbines and how deficiencies – in terms of potential generated power – could be resolved,” said Corke, “The patent portfolio is a package of inventions that were developed to overcome these shortcomings in several ways and improve our ability to harness wind energy.”

    “At FlowPAC, we try to enhance and develop the performance of various technologies,” said Corke. “So whether we are working with an aircraft in relation to drag, jet engines in relation to stall, or wind turbines in relation to energy extraction, we work together to identify the limitations and how we can improve them through flow control.”

    The flow control patent portfolio that was licensed by Tech Transfer at the University of Notre Dame was ceremonially signed over to Aquanis, LLC on April 12, 2016. Neal Fine, the Chief Executive Officer of Aquanis, joined Corke at the signing. To learn more about the flow control research conducted at Notre Dame, click here.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 11:05 am on April 7, 2016 Permalink | Reply
    Tags: , , , Notre Dame University   

    From ND: “Notre Dame physicists discover rare brown dwarf, essential for testing theoretical models” 

    Notre Dame bloc

    Notre Dame University

    April 06, 2016
    Gene Stowe

    1
    A team led by Justin Crepp has discovered HD 4747 B, a rare brown dwarf. As a new mass, age and metallicity benchmark, HD 4747 B will serve as a laboratory for precision astrophysics to test theoretical models.

    A team led by Justin Crepp, the Frank M. Freimann Assistant Professor of Physics at the University of Notre Dame, has discovered a rare brown dwarf, a faint object with properties in between that of a star and planet.

    Artist's concept of a Brown dwarf [not quite a] star. NASA/JPL-Caltech
    Artist’s concept of a Brown dwarf [not quite a] star. NASA/JPL-Caltech

    In addition to taking its picture for the first time, Crepp’s team also determined the brown dwarf’s mass, age and composition — essential information that can be used to “benchmark” the study of these elusive objects.

    Brown dwarfs are objects thought to have initially begun the process of forming a star but were somehow interrupted before they accumulated sufficient mass and core pressure to ignite nuclear fusion — the process by which the Sun ultimately releases energy in the form of light. An important developmental bridge between bona fide stars and exoplanets, brown dwarfs are very difficult to study because their faint glow fades with time due to a lack of sustained nuclear reactions. The discovery of the object, which goes by the name HD 4747 B, was facilitated by 18 years of precise spectral measurements of the star that indicated it hosts an orbiting companion.

    “We suspect that these companions form at the same time and from the same material,” Crepp said. “As such, you can infer physical properties of the brown dwarf from its parent star, like age and composition. There are no other objects for which we know the mass, age and the metallicity simultaneously and also independent of the light that the companion gives off. We can therefore use HD 4747 B as a test-bed to study brown dwarfs, enabling precision astrophysics studies for a directly imaged substellar object.”

    In the past, brown dwarf masses have been estimated using theoretical evolutionary models. Crepp’s team instead calculated the mass of HD 4747 B directly using observations of its orbit in an attempt to help refine brown dwarf models. It is expected that this work will in turn help to inform models for extrasolar planets. Based on a three-dimensional orbit analysis, HD 4747 B has a mass of about 60 Jupiters (a mass of 80 Jupiters is required to ignite nuclear fusion), well below the theoretical estimate of 72 Jupiters, although still within uncertainties. Forthcoming measurements acquired by Crepp’s team will provide yet more stringent tests of the models used by astronomers for brown dwarfs.

    “This field is transitioning from ‘Hey, I found something neat’ to ‘Hey, I know the mass to within a few percent.’ Now, we can test theoretical models,” Crepp said.

    The team detected the object using the Keck telescopes in Hawaii, and published their results in a paper describing the discovery.

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory Interior
    Keck Observatory, Mauna Kea, Hawaii, USA

    The study has been submitted to the Astrophysical Journal. Co-authors of the study include Erica Gonzales and Eric Bechter, both in the Department of Physics at the University of Notre Dame; Benjamin Montet at the Harvard-Smithsonian Center for Astrophysics and the California Institute of Technology; John Asher Johnson at the Harvard-Smithsonian Center for Astrophysics; Danielle Piskorz at the Division of Geological and Planetary Sciences at the California Institute of Technology; Andrew Howard at the Institute for Astronomy at the University of Hawaii; and Howard Isaacson at the University of California Berkeley.

    Science paper:
    The TRENDS High-Contrast Imaging Survey. VI. Discovery of a Mass, Age, and Metallicity Benchmark Brown Dwarf

    Science team:
    Justin R. Crepp 1, Erica J. Gonzales 1, Eric B. Bechter 1, Benjamin T. Montet 2,3, John Asher
    Johnson 2, Danielle Piskorz 3, Andrew W. Howard 4, Howard Isaacson 5

    Affiliations:
    1 Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN, 46556, USA
    2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
    3 Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125
    4 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822
    5 Department of Astronomy, University of California, Berkeley, CA 94720

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
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