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  • richardmitnick 1:51 pm on July 18, 2018 Permalink | Reply
    Tags: , , , , Debra Fischer, EXPRES spectrograph on the Discovery Channel Telescope at Lowell Observatory Flagstaff AZ USA,   

    From Many Worlds: Women in STEM “A New Frontier for Exoplanet Hunting” Debra Fischer Quite a Story 

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    From Many Worlds

    Marc Kaufman

    The spectrum from the newly-assembled EXtreme PREcision Spectrometer (EXPRES) shines on Yale astronomy professor Debra Fischer, who is principal investigator of the project. The stated goal of EXPRES is to find many Earth-size planets via the radial velocity method — something that has never been done. (Ryan Blackman/Yale)

    Radial Velocity Method-Las Cumbres Observatory

    Radial velocity Image via SuperWasp http:// http://www.superwasp.org/exoplanets.htm

    Yale EXtreme PREcision Spectrometer (EXPRES)

    Yale-designed instrument known as EXPRES, which is being installed on the Discovery Channel Telescope in Arizona

    Discovery Channel Telescope at Lowell Observatory, Happy Jack AZ, USA, Altitude 2,360 m (7,740 ft)

    The first exoplanets were all found using the radial velocity method of measuring the “wobble” of a star — movement caused by the gravitational pull of an orbiting planet.

    Radial velocity has been great for detecting large exoplanets relatively close to our solar system, for assessing their mass and for finding out how long it takes for the planet to orbit its host star.

    But so far the technique has not been able to identify and confirm many Earth-sized planets, a primary goal of much planet hunting. The wobble caused by the presence of a planet that size has been too faint to be detected by current radial velocity instruments and techniques.

    However, a new generation of instruments is coming on line with the goal of bringing the radial velocity technique into the small planet search. To do that, the new instruments, together with their telescopes. must be able to detect a sun wobble of 10 to 20 centimeters per second. That’s quite an improvement on the current detection limit of about one meter per second.

    At least three of these ultra high precision spectrographs (or sometimes called spectrometers) are now being developed or deployed. The European Southern Observatory’s ESPRESSO instrument has begun work in Chile; Pennsylvania State University’s NEID spectrograph (with NASA funding) is in development for installation at the Kitt Peak National Observatory in Arizona; and the just-deployed EXPRES spectrograph put together by a team led by Yale University astronomers (with National Science Foundation funding) is in place on the Discovery Channel Telescope at the Lowell Observatory outside of Flagstaff, Arizona.

    Espresso Layout



    Penn State NEID spectrographic instrument schematic for the WIYN telescope at Kitt Peak, AZ, USA Altitude 2,096 m 6,877 ft

    NOAO WIYN 3.5 meter telescope at Kitt Peak, AZ, USA, Altitude 2,096 m (6,877 ft)

    The principal investigator of EXPRES, Debra Fischer, attended the recent University of Cambridge Exoplanets2 conference with some of her team, and there I had the opportunity to talk with them. We discussed the decade-long history of the instrument, how and why Fischer thinks it can break that 1-meter-per-second barrier, and what it took to get it into attached and working.

    This animation shows how astronomers use very precise spectrographs to find exoplanets. As the planet orbits its gravitational pull causes the parent star to move back and forth. This tiny radial motion shifts the observed spectrum of the star by a correspondingly small amount because of the Doppler shift. With super-sensitive spectrographs the shifts can be measured and used to infer details of a planet’s mass and orbit. ESO/L. Calçada)

    One of the earliest and most difficult obstacles to the development of EXPRES, Fischer told me, was that many in the astronomy community did not believe it could work.

    Their view is that precision below that one meter per second of host star movement cannot be measured accurately. Stars have flares, sunspots and a generally constant churning, and many argue that the turbulent nature of stars creates too much “noise” for a precise measurement below that one-meter-per-second level.

    Yet European scientists were moving ahead with their ESPRESSO ultra high precision instrument aiming for that 10-centimeter-per-second mark, and they had a proven record of accomplishing what they set out to do with spectrographs.

    In addition to the definite competiti0n going on, Fisher also felt that radial velocity astronomers needed to make that leap to measuring small planets “to stay in the game” over the long haul.

    She arrived at Yale in 2009 and led an effort to build a spectrograph so stable and precise that it could find an Earth-like planet. To make clear that goal, the instrument is at the center of a project called “100 Earths.”

    Building on experience gained from developing two earlier spectrographs, Fischer and colleagues began the difficult and complicated process of getting backers for EXPRES, of finding a telescope observatory that would house it (The Discovery Channel Telescope at Lowell) and in the end adapting the instrument to the telescope.

    And now comes the actual hard part: finding those Earth-like planets.

    As Fischer described it: “We know from {the Kepler Telescope mission} that most stars have small rocky planets orbiting them. But Kepler looked at stars very far away, and we’ll be looking at stars much, much closer to us.”

    Nonetheless, those small planets will still be extremely difficult to detect due to all that activity on the host suns.

    The 4.3 meter Discovery Channel Telescope in the Lowell Observatory in Arizona. The photons collected by the telescope are delivered via optical fiber to the EXPRES instrument. (Boston University)

    Spectrographs such as EXPRES are instruments astronomers use to study light emitted by planets, stars, and galaxies.

    They are connected to either a ground-based or orbital telescope and they stretch out or split a beam of light into a spectrum of frequencies. That spectrum is then analyzed to determine an object’s speed, direction, chemical composition, or mass. With planets, the work involves determining (via the Doppler shift seen in the spectrum) whether and how much a sun is moving to and away from Earth due to the pull of a planet.

    As Fisher and EXPRES postdoctoral fellow John Brewer explained it, the signal (noise) coming from the turbulence of the star is detectably different from the signal made by the wobble of a star due to the presence of an orbiting planet.

    While these differences — imprinted in the spectrum captured by the spectrograph — have been known for some time, current spectrographs haven’t had sufficient resolving power to actually detect the difference.

    If all works as planned for the EXPRES, Espresso and NEID spectrographs, they will have that necessary resolving power and so can, in effect, filter out the noise from the sun and identify what can only come from a planet-caused wobble. If they succeed, they provide a major new pathway to for astronomers to search for Earth-sized worlds.

    “This is my dream machine, the one I always wanted to build,” Fischer said. “I had a belief that if we went to higher resolution, we could disentangle (the stellar noise from the planet-caused wobble.)

    “I could still be wrong, but I definitely think that trying was the right choice to make.”

    This image shows spectral data from the first light last December of the ESPRESSO instrument on ESO’s Very Large Telescope in Chile. The light from a star has been dispersed into its component colors. This view has been colorised to indicate how the wavelengths change across the image, but these are not exactly the colors that would be seen visually. (ESO/ESPRESSO)

    While Fischer and others have very high hopes for EXPRES, it is not the sort of big ticket project that is common in astronomy. Instead, it was developed and built primarily with a $6 million grant from National Science Foundation.

    It was completed on schedule by the Yale team, though the actual delivering of EXPRES to Arizona and connecting it to the telescope turned out to be a combination of hair-raising and edifying.

    Twice, she said, she drove from New Haven to Flagstaff with parts of the instrument; each trip in a Penske rental truck and with her son Ben helping out.

    And then when the instrumentation was in process late last year, Fischer and her team learned that funds for the scientists and engineers working on that process had come to an end.

    She was desperate, and sent a long-shot email to Francesco Pepe of University of Geneva, the lead scientist and wizard builder of several European spectrographs, including ESPRESSO. In theory, he and his instrument — which went into operation late last year at the ESO Very Large Telescope in Chile — will be competing with EXPRES for discoveries and acknowledgement.

    Nonetheless, Pepe heard Fischer out and understood the predicament she was in. ESPRESSO had been installed and so he was able to contact an associate who freed up two instrumentation specialists who flew to Flagstaff to finish the work. It was, Fischer said, an act of collegial generosity and scientific largesse that she will never forget.

    Fischer is at the Lowell observatory now, using the Arizona monsoon as a time to clean up many details before the team returns to full-time observing. She write about her days in an EXPRES blog. Earlier, in March after the instrumentation had been completed and observing had commenced, she wrote this:

    “Years of work went into EXPRES and as I look at this instrument, I am surprised that I ever had the audacity to start this project. The moment of truth starts now. It will take us a few more months of collecting and analyzing data to know if we made the right design decisions and I feel both humbled and hopeful. I’m proud of the fact that our design decisions were driven by evidence gleaned from many years of experience. But did I forget anything?”

    See the full article here .


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    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

  • richardmitnick 2:34 pm on January 30, 2017 Permalink | Reply
    Tags: Debra Fischer, , SCIENCE LINE, ,   

    From Yale via Science Line: Women in STEM: “Breaking limits in science and life” Debra Fischer 

    Yale University bloc

    Yale University



    January 18, 2017
    Cici Zhang

    Debra Fischer, a Yale astronomer, hopes to find Earth-like planets outside our solar system, especially those close enough to reach by unmanned spacecraft. [Image Credit: Flickr user NASA | CC BY-NC-ND 2.0]

    A planet, Debra Fischer likes to tell her Yale students, “is a billion times fainter than the star.” Speaking from experience, she’s been searching for distant planets in the vastness of space for almost two decades and has been finding them with impressive regularity.

    Listening to Fischer lecturing undergraduates in an amphitheater classroom, you immediately recognize her as an engaging explainer and committed teacher. But she’s much more: a female pioneer in a testosterone-infused field, a social activist in science, and a cutting-edge researcher finishing a new machine that may soon rock the field of planet-hunting.

    Back in her sunlit office in a converted 19th-century mansion on Yale’s Science Hill, Fischer explains that downstairs, her graduate students are building the most precise spectrometer ever used in exoplanet research.

    Spectrometers are crucial tools for planet hunters like Fischer, who use them to measure the wavelengths of light from distant stars. Periodic changes in starlight wavelengths suggest an orbiting planet is tugging the star — bluer as the star moves towards us, redder away.

    In August, this technique helped astronomers find an Earth-like planet orbiting our nearest star neighbor, the red dwarf star Proxima Centauri. Fischer is sure that many more discoveries will be made soon with the help of more powerful tools like the ultrasensitive $5 million spectrometer she’s building, known as EXPRES, for EXtreme PREcision Spectrometer.

    “I’ve spent twenty years trying to get to this point,” Fischer says. “Now I can take everything that I’ve learned, thought about, worked on and struggled with, put them into this instrument which is going be better than anything that’s been built before.”

    With the help of better instruments like EXPRES, Fischer says, it may only be a matter of time until we find nearby exoplanets capable of harboring life. “We just need to figure out what we can do to push the limits [of our observational power],” she says.

    Represented here as an artist’s conception, the planet Proxima Centauri b excites a lot of people because it is just slightly larger than Earth and is only 4.2 light years away. [Image Credit: Flickr user European Southern Observatory | CC BY 2.0]

    A youthful-looking 63, Fischer is the mother of three grown children. She lives in New Haven, Connecticut with her husband Ed and two Australian shepherds, Radar and Rocket. For two decades, she’s been hunting exoplanets — and finding hundreds of them, including the first multi-planet system ever discovered.

    Fischer is now one of few prominent women astronomers in the United States, says Didier Queloz, a professor of astrophysics at the University of Cambridge and Geneva University. He believes Fischer’s success comes from her openness to new ideas. Fischer is well aware of “key technical developments to improve the stability and the precision of the machine she is building,” says Queloz.

    What makes the EXPRES spectrometer unique is its targeted precision. To find more planets like Earth, Fischer says, we need to be able to detect wobbles ten times subtler than we are currently capable of picking up with the spectrometer that found the planet Proxima Centauri b.

    “Earth only induces a velocity wiggle of 10-centimeter per second on the sun,” says Fischer. To detect a signal almost as weak as Earth’s, she aims to push the precision limit of EXPRES down to 20-centimeter per second from the current 100-centimeter per second.

    Next fall, Fischer will install EXPRES on the Discovery Channel Telescope in Arizona.

    Discovery Channel Telescope at Lowell Observatory, Happy Jack AZ, USA
    Discovery Channel Telescope at Lowell Observatory, Happy Jack AZ, USA

    “She is willing to try something new and risky and harder,” says Sara Seager, a professor of planetary science at MIT and a 2013 MacArthur Fellow. “That’s the only way to make progress.”

    Fischer is used to taking risks. When she studied for her master’s degree in physics at San Francisco State University in the early 1990s, there were never more than two women in any of her classes — often there were none at all.

    But later, as she pursued her doctorate at the University of California, Santa Cruz, there were two women on the astronomy faculty: Sandra Faber and Jean Brodie. “It was unheard of,” says Fischer. “You don’t say this out loud, but subconsciously it’s registering: yeah, this is a place where I could be.”

    Last summer, when Fischer organized a meeting about exoplanet instrumentation at Yale, she made a point of inviting women to chair sessions and give talks. But in the end, only 14 percent of attendees were women. “It was really disappointing,” Fischer says, especially when a male NASA project manager told her it’s because the field is technical and women don’t like instrumentation.

    MIT’s Seager has seen improvement over the years. More and more women are working as postdocs and junior faculty members in astronomy, she says, and a “relatively large number” — “large” is not yet the right word — have reached the highest level in academia, full professor, like herself and Fischer.

    With EXPRES, she hopes to find Earth-like exoplanets in nearby star systems as part of her 100 Earths Project. But there’s no guarantee the machine will meet those ambitious expectations. EXPRES, and Fischer, might fail — which is why many of her colleagues admire her so much.

    There was plenty of competitive machismo in exoplanet hunting, especially in the early 2000s when discoveries were coming fast and astronomers were jockeying for credit. “I hate to be gender biased on this, but it was hard for me. And I think for many people who are sensitive — they would not like that environment,” Fischer says.

    Fischer’s willingness to speak up also manifested itself in 2013, when she led a boycott of a NASA meeting — risking her future career and funding. After learning from Ji Wang, her then-postdoctoral fellow, that six Chinese researchers including Wang were banned from the meeting, Fischer went on Facebook and called out the space agency. It wasn’t fair to ban “people who are doing incredibly innovative work,” she explains.

    At the time, Wang says, some colleagues worried that Fischer’s outspokenness could imperil her research support, but Fischer says she had no regrets. Although the boycott “caused a big problem and a lot of people were unhappy with me,” she says, getting people to like her is not her priority. “The first thing for me is making the world a more just, more fair place.” In the end, the meeting organizer backed off, and Wang and the other Chinese researchers were allowed to attend.

    Wang is now a postdoctoral associate at the California Institute of Technology. When Fischer comes to California, he catches up with her and sometimes takes her out for dim sum.

    “Although one man or one woman cannot change the entire attitude of the government,” Wang says, individual actions matter. He says Fischer not only taught him how to be a successful scientist but also “how to be a decent human being.”

    Speaking of the future as a step-by-step process, Fischer quotes Isaac Newton: “‘If I see further than others it is because I stood on the shoulders of giants.’ We can see further than others now because of the work that the astronomers who came before us did.”

    Fischer thinks now is the time for her to be that “shoulder” for her students. “One thing I can do in my career is to figure out how to push the spectrometer’s precision to the limit” of 10-centimeters per second, says Fischer. “As my students are climbing up onto my shoulder, they will find 100 nearby stars that have Earth-like planets, and they will figure out if there is life out there.”

    “That’s not hundreds of years away. That’s the next generation.”

    See the full article here .

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    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

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