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  • richardmitnick 8:48 pm on August 5, 2021 Permalink | Reply
    Tags: "Unparalleled bounty of oscillating red giant stars detected", Asteroseismology, , , , , , , University of Hawaiʻi-Manoa Institute for Astronomy (IfA)(US)   

    From University of Hawai’i-Manoa (US) : “Unparalleled bounty of oscillating red giant stars detected” 

    From University of Hawai’i-Manoa (US)

    August 4, 2021

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    Illustration of red giant stars near and far sweeping across the sky. Credit: Chris Smith (KBRwyle) NASA’s Goddard Space Flight Center (US).

    An unprecedented collection of pulsating giant red stars has been identified by astronomers at the University of Hawaiʻi-Manoa Institute for Astronomy (IfA)(US). Using observations from NASA’s Transiting Exoplanet Survey Satellite (TESS), the researchers detected the stars, whose rhythms arise from internal sound waves and provide the opening chords of a symphonic exploration of our galactic neighborhood.
    ______________________________________________________________________________________________________________
    National Aeronautics Space Agency (US)/Massachusetts Institute of Technology (US) TESS

    NASA/MIT Tess in the building.

    National Aeronautics Space Agency (US)/Massachusetts Institute of Technology(US) TESS – Transiting Exoplanet Survey Satellite replaced the Kepler Space Telescope in search for exoplanets. TESS is a NASA Astrophysics Explorer mission led and operated by Massachusetts Institute of Technology (US), and managed by NASA’s Goddard Space Flight Center (US).

    Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Center for Astrophysics – Harvard and Smithsonian; MIT Lincoln Laboratory; and the NASA Space Telescope Science Institute (US) in Baltimore.


    ______________________________________________________________________________________________________________

    Since its launch in 2018, TESS has primarily hunted for exoplanets–worlds beyond our solar system. But its sensitive measurements of changing stellar brightness make the telescope ideal for observing stellar oscillations or material within the internal structure of stars. It’s an area of research called asteroseismology.

    “Our initial result, using only a month of stellar measurements from TESS’s first two years, shows that we can determine the masses and sizes of these oscillating giants with high precision that will only improve as TESS goes on,” said Marc Hon, a NASA Hubble Fellow at IfA. “What’s really unparalleled is that TESS’s broad coverage allows us to make these measurements uniformly across almost the entire sky.”

    This large bounty of oscillating red giants will be used for unprecedented detailed studies using the ground-based telescopes on Maunakea.

    “We have already started follow-up observations of some of the most intriguing oddballs we have uncovered in our large TESS dataset, which will tell us more about their origin,” said Hon. “We have just scratched the surface of the treasure trove of data enabled by TESS.”

    Hon presented the research on Wednesday during the TESS Science Conference, an event held virtually, August 2–6 and supported by the Massachusetts Institute of Technology (US) in Cambridge, where scientists discuss the latest results of the mission. He is the lead author of the study that is accepted for publication in The Astrophysical Journal, with co-authors including fellow IfA colleagues Jamie Tayar and Daniel Huber.

    Widening opportunities

    3
    TESS has identified more than 158,000 pulsating red giants over nearly the entire sky. Credit: NASA’s Goddard Space Flight Center/Chris Smith (KBRwyle).

    Oscillations in the Sun were first observed in the 1960s. But solar-like oscillations in thousands of stars weren’t detected until the French-led Convection, Rotation and Planetary Transits space telescope, which operated from 2006 to 2013. NASA’s Kepler and K2 missions, which surveyed from 2009 to 2018, found tens of thousands of oscillating giants. TESS is expanding access to these oscillations through its observations in space.

    NASA Kepler Space Telescope (US).

    “With a sample this large, giants that might occur only one percent of the time become pretty numerous,” said Tayar, a Hubble Postdoctoral Fellow at IfA. “Now we can start thinking about finding even rarer stars.”

    TESS monitors large swaths of the sky for about a month at a time using its four cameras, covering about 75% of the sky during its two-year primary mission. Each camera captures a full image 24-by-24 degrees (48 times the size of the Moon in our sky) across, every 30 minutes. Since late summer 2020, the cameras have been collecting these images at an even faster rate.

    The images are used to generate light curves—graphs of changing brightness—for nearly 24 million stars, each spanning 27 days, the length of time TESS stares at one patch of the sky. To sift through this immense accumulation of measurements, Hon and his colleagues taught a computer how to recognize pulsating giants. The team used machine learning, a form of artificial intelligence that trains computers to make decisions based on general patterns without explicitly programming them.

    To train the system, the team used Kepler light curves for more than 150,000 stars, of which about 20,000 were oscillating red giants. When the neural network finished processing all of the TESS data, it had identified 158,505 pulsating giants.

    The team determined colors and distances for each giant using data from the European Space Agency’s Gaia mission, and plotted the masses of these stars across the sky. A fundamental prediction in galactic astronomy is that younger, higher-mass stars should lie closer to the plane of the galaxy, marked by the high density of stars that create the glow of the Milky Way in the night sky.

    “Our map demonstrates for the first time that this is indeed the case across nearly the whole sky,” said Huber. “With the help of Gaia, TESS has now given us tickets to a red giant concert in the sky.”

    European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) GAIA satellite

    This research is an example of UH Mānoa’s goal of Excellence in Research: Advancing the Research and Creative Work Enterprise, one of four goals identified in the 2015–25 Strategic Plan, updated in December 2020.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    System Overview

    The University of Hawai‘i (US) includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

    The University of Hawaiʻi system, formally the University of Hawaiʻi (US) is a public college and university system that confers associate, bachelor’s, master’s, and doctoral degrees through three university campuses, seven community college campuses, an employment training center, three university centers, four education centers and various other research facilities distributed across six islands throughout the state of Hawaii in the United States. All schools of the University of Hawaiʻi system are accredited by the Western Association of Schools and Colleges. The U.H. system’s main administrative offices are located on the property of the University of Hawaiʻi at Mānoa in Honolulu CDP.

    The University of Hawaiʻi-Mānoa (US) is the flagship institution of the University of Hawaiʻi (US) system. It was founded as a land-grant college under the terms of the Morrill Acts of 1862 and 1890. Programs include Hawaiian/Pacific Studies, Astronomy, East Asian Languages and Literature, Asian Studies, Comparative Philosophy, Marine Science, Second Language Studies, along with Botany, Engineering, Ethnomusicology, Geophysics, Law, Business, Linguistics, Mathematics, and Medicine. The second-largest institution is the University of Hawaiʻi at Hilo on the “Big Island” of Hawaiʻi, with over 3,000 students. The University of Hawaiʻi-West Oʻahu in Kapolei primarily serves students who reside in Honolulu’s western and central suburban communities. The University of Hawaiʻi Community College system comprises four community colleges island campuses on O’ahu and one each on Maui, Kauaʻi, and Hawaiʻi. The schools were created to improve accessibility of courses to more Hawaiʻi residents and provide an affordable means of easing the transition from secondary school/high school to college for many students. University of Hawaiʻi education centers are located in more remote areas of the State and its several islands, supporting rural communities via distance education.

    Research facilities

    Center for Philippine Studies
    Cancer Research Center of Hawaiʻi
    East-West Center
    Haleakalā Observatory
    Hawaiʻi Natural Energy Institute
    Institute for Astronomy
    Institute of Geophysics and Planetology
    Institute of Marine Biology
    Lyon Arboretum
    Mauna Kea Observatory
    W. M. Keck Observatory
    Waikīkī Aquarium

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth.

    The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the island of Hawai’i feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

     
  • richardmitnick 10:55 am on May 29, 2021 Permalink | Reply
    Tags: "Alien stars found in our Milky Way", Archeoastronomy, Asteroseismology, , , , , , , , ,   

    From University of Birmingham (UK) via EarthSky : “Alien stars found in our Milky Way” 

    From University of Birmingham (UK)

    via

    1

    EarthSky

    May 25, 2021
    Theresa Wiegert

    1
    Infrared image of stars at the center of our Milky Way galaxy, via the Spitzer Space Telescope.

    Observing in infrared makes it possible to peer behind the gas clouds that otherwise cover the central region of the galaxy. There are around 10 million stars within just 3.3 light-years of the galactic center. These are dominated by red giants, the same kind of old stars found to be from another galaxy in this study. Image via National Aeronautics Space Agency (US)/ JPL-Caltech (US)/ S. Stolovy (NASA Spitzer Science Center (US)/California Institute of Technology (US)).

    Astronomers used a new technique – asteroseismology combined with spectroscopy – to pinpoint the ages of a sample of around 100 old red giant stars in the Milky Way.

    They were able to reach a much higher accuracy of the stars’ ages, they said in a statement on May 17, 2021. And they also found that a number of those red giant stars did not originate in the Milky Way! They are instead alien stars, which came here from another galaxy. Their original home in space was Gaia Enceladus (also known as the Gaia Sausage), a dwarf galaxy that collided and merged with our Milky way galaxy about 10 billion years ago.

    3
    Artist’s concept of the stars from dwarf galaxy Gaia Enceladus, which merged with the Milky Way some 10 billion years ago. The Milky Way is in the center of the illustration, shown from above, and the Gaia Enceladus stars – debris of the dwarf galaxy – are represented by little arrows – vectors – that show their position and the direction in which they move. The data are from a computer simulation. Image via European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU).

    2
    This Hubble Space Telescope (HST) image of a dense swarm of stars shows the central region of the globular cluster NGC 2808 and its 3 generations of stars. NASA, European Space Agency, A. Sarajedini (University of Florida (US)) and G. Piotto (University of Padua [Università degli Studi di Padova] (IT))

    This new research was published on May 17, 2021, in the peer-reviewed journal Nature Astronomy.

    What do alien stars tell us?

    So the idea here is that the Milky Way galaxy had already started forming many of its stars before a dwarf galaxy came by and merged with our galaxy, bringing its own stars with it. This event took place around 8-11 billion years ago. In contrast, the age of the Milky Way is about 13.6 billion years, give or take a few.

    This merger, then, happened early in our galaxy’s history.

    The dwarf galaxy – or the remnants of it – go today under the name Gaia Enceladus or the Gaia Sausage [above], because of the highly elongated shape it forms – like a sausage – as seen from data from the Gaia mission.

    In Greek mythology, Enceladus was the offspring of the goddess Gaia. It is also, incidentally, the name for one of Saturn’s moons.

    In this new research, the astronomers were able to identify stars that are remnants of the merger. These stars provide a way of looking back to the distant past, when the merger took place. Josefina Montalbán at the University of Birmingham is the lead author on the paper. She said:

    “The chemical composition, location and motion of the stars we can observe today in the Milky Way contain precious information about their origin. As we increase our knowledge of how and when these stars were formed, we can start to better understand how the merger of Gaia-Enceladus with the Milky Way affected the evolution of our galaxy.”

    How did astronomers find the stars?

    These astronomers had targeted a sample of 100 old stars observed with the Kepler mission.

    These are red giant stars, at the end of their lives.

    The team used data from three Milky Way research instruments to measure the stars’ ages, all with the task of mapping and analyzing Milky Way stars. One instrument was Kepler, as mentioned previously. The other two were the Gaia satellite and APOGEE.

    With data from these instruments, the astronomers used the technique of asteroseismology that studies how stars oscillate. That is, the technique measures regular variations within the star. Asteroseismology is similar to helioseismology, the study of oscillations in the sun. Learning how a star oscillates lets astronomers gain info about a star’s size and internal structure, which, in turn, will let them estimate the star’s age.

    Team member Mathieu Vrard at Ohio State University’s (US) Department of Astronomy, said:

    “[It] allows us to get very precise ages for the stars, which are important in determining the chronology of when events happened in the early Milky Way.”

    In addition, the astronomers also used spectroscopy – the study of the stellar spectrum – to learn the chemical composition of the stars. This also helps with age determination, and in combination, the methods let the astronomers determine the ages to an unprecedented precision.

    The astronomers noticed that a number of them were of the same age, and that this age was a bit younger than most of the stars that we know started their lives in the Milky Way.

    Team member Andrea Miglio at the University of Bologna [Alma mater studiorum – Università di Bologna](IT) added:

    “We have shown the huge potential of asteroseismology in combination with spectroscopy to deliver precise, accurate relative ages for individual, very old, stars. Taken together, these measurements contribute to sharpen our view on the early years of our galaxy and promise a bright future for [Milky Way] archeoastronomy.”

    Now the researchers want to apply their approach to larger samples of stars to get a better view of the Milky Way’s formation history and evolution.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    University of Birmingham (UK) has been challenging and developing great minds for more than a century. Characterised by a tradition of innovation, research at the University has broken new ground, pushed forward the boundaries of knowledge and made an impact on people’s lives. We continue this tradition today and have ambitions for a future that will embed our work and recognition of the Birmingham name on the international stage.

    The University of Birmingham is a public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen’s College, Birmingham (founded in 1825 as the Birmingham School of Medicine and Surgery), and Mason Science College (established in 1875 by Sir Josiah Mason), making it the first English civic or ‘red brick’ university to receive its own royal charter. It is a founding member of both the Russell Group (UK) of British research universities and the international network of research universities, Universitas 21.

    The student population includes 23,155 undergraduate and 12,605 postgraduate students, which is the 7th largest in the UK (out of 169). The annual income of the institution for 2019–20 was £737.3 million of which £140.4 million was from research grants and contracts, with an expenditure of £667.4 million.

    The university is home to the Barber Institute of Fine Arts, housing works by Van Gogh, Picasso and Monet; the Shakespeare Institute; the Cadbury Research Library, home to the Mingana Collection of Middle Eastern manuscripts; the Lapworth Museum of Geology; and the 100-metre Joseph Chamberlain Memorial Clock Tower, which is a prominent landmark visible from many parts of the city. Academics and alumni of the university include former British Prime Ministers Neville Chamberlain and Stanley Baldwin, the British composer Sir Edward Elgar and eleven Nobel laureates.

    Scientific discoveries and inventions

    The university has been involved in many scientific breakthroughs and inventions. From 1925 until 1948, Sir Norman Haworth was Professor and Director of the Department of Chemistry. He was appointed Dean of the Faculty of Science and acted as Vice-Principal from 1947 until 1948. His research focused predominantly on carbohydrate chemistry in which he confirmed a number of structures of optically active sugars. By 1928, he had deduced and confirmed the structures of maltose, cellobiose, lactose, gentiobiose, melibiose, gentianose, raffinose, as well as the glucoside ring tautomeric structure of aldose sugars. His research helped to define the basic features of the starch, cellulose, glycogen, inulin and xylan molecules. He also contributed towards solving the problems with bacterial polysaccharides. He was a recipient of the Nobel Prize in Chemistry in 1937.

    The cavity magnetron was developed in the Department of Physics by Sir John Randall, Harry Boot and James Sayers. This was vital to the Allied victory in World War II. In 1940, the Frisch–Peierls memorandum, a document which demonstrated that the atomic bomb was more than simply theoretically possible, was written in the Physics Department by Sir Rudolf Peierls and Otto Frisch. The university also hosted early work on gaseous diffusion in the Chemistry department when it was located in the Hills building.

    Physicist Sir Mark Oliphant made a proposal for the construction of a proton-synchrotron in 1943, however he made no assertion that the machine would work. In 1945, phase stability was discovered; consequently, the proposal was revived, and construction of a machine that could surpass proton energies of 1 GeV began at the university. However, because of lack of funds, the machine did not start until 1953. The DOE’s Brookhaven National Laboratory (US) managed to beat them; they started their Cosmotron in 1952, and had it entirely working in 1953, before the University of Birmingham.

    In 1947, Sir Peter Medawar was appointed Mason Professor of Zoology at the university. His work involved investigating the phenomenon of tolerance and transplantation immunity. He collaborated with Rupert E. Billingham and they did research on problems of pigmentation and skin grafting in cattle. They used skin grafting to differentiate between monozygotic and dizygotic twins in cattle. Taking the earlier research of R. D. Owen into consideration, they concluded that actively acquired tolerance of homografts could be artificially reproduced. For this research, Medawar was elected a Fellow of the Royal Society. He left Birmingham in 1951 and joined the faculty at University College London (UK), where he continued his research on transplantation immunity. He was a recipient of the Nobel Prize in Physiology or Medicine in 1960.

     
  • richardmitnick 9:39 pm on May 13, 2021 Permalink | Reply
    Tags: "Mixing Massive Stars", Asteroseismology, , , , , , ,   

    From University of California-Santa Barbara (US) : “Mixing Massive Stars” 

    UC Santa Barbara Name bloc

    From University of California-Santa Barbara (US)

    May 13, 2021
    Harrison Tasoff
    (805) 893-7220
    harrisontasoff@ucsb.edu

    1
    A simulation of a 3-solar-mass star shows the central, convective core and the waves it generates in the rest of the star’s interior. Photo Credit: Philipp Edelmann.

    Astronomers commonly refer to massive stars as the chemical factories of the Universe. They generally end their lives in spectacular supernovae, events that forge many of the elements on the periodic table. How elemental nuclei mix within these enormous stars has a major impact on our understanding of their evolution prior to their explosion. It also represents the largest uncertainty for scientists studying their structure and evolution.

    A team of astronomers led by May Gade Pedersen, a postdoctoral scholar at UC Santa Barbara’s Kavli Institute for Theoretical Physics, have now measured the internal mixing within an ensemble of these stars using observations of waves from their deep interiors. While scientists have used this technique before, this paper marks the first time this has been accomplished for such a large group of stars at once. The results, published in Nature Astronomy, show that the internal mixing is very diverse, with no clear dependence on a star’s mass or age.

    Stars spend the majority of their lives fusing hydrogen into helium deep in their cores. However, the fusion in particularly massive stars is so concentrated at the center that it leads to a turbulent convective core similar to a pot of boiling water. Convection, along with other processes like rotation, effectively removes helium ash from the core and replaces it with hydrogen from the envelope. This enables the stars to live much longer than otherwise predicted.

    Astronomers believe this mixing arises from various physical phenomena, like internal rotation and internal seismic waves in the plasma excited by the convecting core. However, the theory has remained largely unconstrained by observations as it occurs so deep within the star. That said, there is an indirect method of peering into stars: asteroseismology, the study and interpretation of stellar oscillations. The technique has parallels to how seismologists use earthquakes to probe the interior of the Earth.

    “The study of stellar oscillations challenges our understanding of stellar structure and evolution,” Pedersen said. “They allow us to directly probe the stellar interiors and make comparisons to the predictions from our stellar models.”

    Pedersen and her collaborators from Katholieke Universiteit Leuven [Katholieke Universiteit te Leuven] (BE), the Hasselt University [Universiteit Hasselt] (BE), and the The University of Newcastle (AU) have been able to derive the internal mixing for an ensemble of such stars using asteroseismology. This is the first time such a feat has been achieved, and was possible thanks only to a new sample of 26 slowly pulsating B-type stars with identified stellar oscillations from NASA’s Kepler mission.

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    Mixing transports fused material away and replaces it with more hydrogen fuel from the star’s outer layers.
    Credit: MAY GADE PEDERSEN.

    Slowly pulsating B-type stars are between three and eight times more massive than the Sun. They expand and contract on time scales of the order of 12 hours to 5 days, and can change in brightness by up to 5%. Their oscillation modes are particularly sensitive to the conditions near the core, Pedersen explained.

    “The internal mixing inside stars has now been measured observationally and turns out to be diverse in our sample, with some stars having almost no mixing while others reveal levels a million times higher,” Pedersen said. The diversity turns out to be unrelated to the mass or age of the star. Rather, it’s primarily influenced by the internal rotation, though that is not the only factor at play.

    “These asteroseismic results finally allow astronomers to improve the theory of internal mixing of massive stars, which has so far remained uncalibrated by observations coming straight from their deep interiors,” she added.

    The precision at which astronomers can measure stellar oscillations depends directly on how long a star is observed. Increasing the time from one night to one year results in a thousand-fold increase in the measured precision of oscillation frequencies.

    “May and her collaborators have really shown the value of asteroseismic observations as probes of the deep interiors of stars in a new and profound way,” said KITP Director Lars Bildsten, the Gluck Professor of Theoretical Physics. “I am excited to see what she finds next.”

    The best data currently available for this comes from the Kepler space mission, which observed the same patch of the sky for four continuous years. The slowly pulsating B-type stars were the highest mass pulsating stars that the telescope observed. While most of these are slightly too small to go supernova, they do share the same internal structure as the more massive stellar chemical factories. Pedersen hopes insights gleaned from studying the B type stars will shed light on the inner workings of their higher mass, O type counterparts.

    She plans to use data from NASA’s Transiting Exoplanet Survey Satellite (TESS) to study groups of oscillating high-mass stars in OB associations.

    National Aeronautics Space Agency (US)/Massachusetts Institute of Technology (US) TESS

    Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Center for Astrophysics – Harvard and Smithsonian; MIT Lincoln Laboratory; and the NASA Space Telescope Science Institute (US) in Baltimore.

    These groups comprise 10 to more than 100 massive stars between 3 and 120 solar masses. Stars in OB associations are born from the same molecular cloud and share similar ages, she explained. The large sample of stars, and constraint from their common ages, provides exciting new opportunities to study the internal mixing properties of high-mass stars.

    In addition to unveiling the processes hidden within stellar interiors, research on stellar oscillations can also provide information on other properties of the stars.

    “The stellar oscillations not only allow us to study the internal mixing and rotation of the stars, but also determine other stellar properties such as mass and age,” Pedersen explained. “While these are both two of the most fundamental stellar parameters, they are also some of the most difficult to measure.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    UC Santa Barbara Seal

    The University of California-Santa Barbara (US) is a public land-grant research university in Santa Barbara, California, and one of the ten campuses of the University of California(US) system. Tracing its roots back to 1891 as an independent teachers’ college, UCSB joined the University of California system in 1944, and is the third-oldest undergraduate campus in the system.

    The university is a comprehensive doctoral university and is organized into five colleges and schools offering 87 undergraduate degrees and 55 graduate degrees. It is classified among “R1: Doctoral Universities – Very high research activity”. According to the National Science Foundation(US), UC Santa Barbara spent $235 million on research and development in fiscal year 2018, ranking it 100th in the nation. In his 2001 book The Public Ivies: America’s Flagship Public Universities, author Howard Greene labeled UCSB a “Public Ivy”.

    UC Santa Barbara is a research university with 10 national research centers, including the Kavli Institute for Theoretical Physics (US) and the Center for Control, Dynamical-Systems and Computation. Current UCSB faculty includes six Nobel Prize laureates; one Fields Medalist; 39 members of the National Academy of Sciences; 27 members of the National Academy of Engineering; and 34 members of the American Academy of Arts and Sciences. UCSB was the No. 3 host on the ARPANET and was elected to the Association of American Universities in 1995. The faculty also includes two Academy and Emmy Award winners and recipients of a Millennium Technology Prize; an IEEE Medal of Honor; a National Medal of Technology and Innovation; and a Breakthrough Prize in Fundamental Physics.

    The UC Santa Barbara Gauchos compete in the Big West Conference of the NCAA Division I. The Gauchos have won NCAA national championships in men’s soccer and men’s water polo.

    History

    UCSB traces its origins back to the Anna Blake School, which was founded in 1891, and offered training in home economics and industrial arts. The Anna Blake School was taken over by the state in 1909 and became the Santa Barbara State Normal School which then became the Santa Barbara State College in 1921.

    In 1944, intense lobbying by an interest group in the City of Santa Barbara led by Thomas Storke and Pearl Chase persuaded the State Legislature, Gov. Earl Warren, and the Regents of the University of California to move the State College over to the more research-oriented University of California system. The State College system sued to stop the takeover but the governor did not support the suit. A state constitutional amendment was passed in 1946 to stop subsequent conversions of State Colleges to University of California campuses.

    From 1944 to 1958, the school was known as Santa Barbara College of the University of California, before taking on its current name. When the vacated Marine Corps training station in Goleta was purchased for the rapidly growing college Santa Barbara City College moved into the vacated State College buildings.

    Originally the regents envisioned a small several thousand–student liberal arts college a so-called “Williams College (US) of the West”, at Santa Barbara. Chronologically, UCSB is the third general-education campus of the University of California, after UC Berkeley (US) and UCLA (US) (the only other state campus to have been acquired by the UC system). The original campus the regents acquired in Santa Barbara was located on only 100 acres (40 ha) of largely unusable land on a seaside mesa. The availability of a 400-acre (160 ha) portion of the land used as Marine Corps Air Station Santa Barbara until 1946 on another seaside mesa in Goleta, which the regents could acquire for free from the federal government, led to that site becoming the Santa Barbara campus in 1949.

    Originally only 3000–3500 students were anticipated but the post-WWII baby boom led to the designation of general campus in 1958 along with a name change from “Santa Barbara College” to “University of California, Santa Barbara,” and the discontinuation of the industrial arts program for which the state college was famous. A chancellor- Samuel B. Gould- was appointed in 1959.

    In 1959 UCSB professor Douwe Stuurman hosted the English writer Aldous Huxley as the university’s first visiting professor. Huxley delivered a lectures series called The Human Situation.

    In the late ’60s and early ’70s UCSB became nationally known as a hotbed of anti–Vietnam War activity. A bombing at the school’s faculty club in 1969 killed the caretaker Dover Sharp. In the spring of 1970 multiple occasions of arson occurred including a burning of the Bank of America branch building in the student community of Isla Vista during which time one male student Kevin Moran was shot and killed by police. UCSB’s anti-Vietnam activity impelled then-Gov. Ronald Reagan to impose a curfew and order the National Guard to enforce it. Armed guardsmen were a common sight on campus and in Isla Vista during this time.

    In 1995 UCSB was elected to the Association of American Universities– an organization of leading research universities with a membership consisting of 59 universities in the United States (both public and private) and two universities in Canada.

    On May 23, 2014 a killing spree occurred in Isla Vista, California, a community in close proximity to the campus. All six people killed during the rampage were students at UCSB. The murderer was a former Santa Barbara City College student who lived in Isla Vista.

    Research activity

    According to the National Science Foundation (US), UC Santa Barbara spent $236.5 million on research and development in fiscal 2013, ranking it 87th in the nation.

    From 2005 to 2009 UCSB was ranked fourth in terms of relative citation impact in the U.S. (behind Massachusetts Institute of Technology (US), California Institute of Technology(US), and Princeton University (US)) according to Thomson Reuters.

    UCSB hosts 12 National Research Centers, including the Kavli Institute for Theoretical Physics, the National Center for Ecological Analysis and Synthesis, the Southern California Earthquake Center, the UCSB Center for Spatial Studies, an affiliate of the National Center for Geographic Information and Analysis, and the California Nanosystems Institute. Eight of these centers are supported by the National Science Foundation. UCSB is also home to Microsoft Station Q, a research group working on topological quantum computing where American mathematician and Fields Medalist Michael Freedman is the director.

    Research impact rankings

    The Times Higher Education World University Rankings ranked UCSB 48th worldwide for 2016–17, while the Academic Ranking of World Universities (ARWU) in 2016 ranked UCSB 42nd in the world; 28th in the nation; and in 2015 tied for 17th worldwide in engineering.

    In the United States National Research Council rankings of graduate programs, 10 UCSB departments were ranked in the top ten in the country: Materials; Chemical Engineering; Computer Science; Electrical and Computer Engineering; Mechanical Engineering; Physics; Marine Science Institute; Geography; History; and Theater and Dance. Among U.S. university Materials Science and Engineering programs, UCSB was ranked first in each measure of a study by the National Research Council of the NAS.

    The Centre for Science and Technologies Studies at

     
  • richardmitnick 7:32 pm on April 22, 2021 Permalink | Reply
    Tags: "Spinning stars speedier than expected", Asteroseismology, , , , , ,   

    From University of Birmingham (UK) via COSMOS (AU)</a: "Spinning stars speedier than expected" 

    From University of Birmingham (UK)

    via

    Cosmos Magazine bloc

    COSMOS (AU)

    23 April 2021
    Lauren Fuge

    1
    The study of vibrations within stars (called asteroseismology) can be used to measure properties such as a star’s rotation, mass and age. Credit: Mark Garlick / University of Birmingham.

    Asteroseismologists confirm older stars rotate faster than previously thought.

    From planets to galaxies, asteroids to black holes, everything in the universe moves and spins, largely thanks to the good old conservation of angular momentum.

    Stars are born spinning too, but as they age, they begin to slow down. Astronomers theorise that this is due to a process called “magnetic braking”, where solar winds are caught by the star’s magnetic field and rob it of angular momentum.

    Now, a new study led by the UK’s University of Birmingham shows that old stars aren’t slowing down as quickly as the magnetic braking theory predicts.

    This confirms previous observations made back in 2016, which studied the spinning of stars by tracking the movement of dark spots across their surface. But this new paper – published in Nature Astronomy – uses a different method called asteroseismology.

    Seismology may be a more familiar field: it’s the study of seismic waves (vibrations) through the Earth’s crust, used to predict and understand earthquakes. Asteroseismology uses a similar principle to study the sound waves that move through the internal structure of stars.

    These waves cause oscillations of certain frequencies, which are visible on the surface of the star as vibrations. As the stars spin, the frequencies change slightly – imagine listening to the sirens of two ambulances change as they drive around a roundabout.

    By observing how the surface vibrations vary over time, the research team could calculate the star’s rate of rotation – as well as other properties like its mass and age.

    “Although we’ve suspected for some time that older stars rotate faster than magnetic braking theories predict, these new asteroseismic data are the most convincing yet to demonstrate that this ‘weakened magnetic braking’ is actually the case,” says lead author Oliver Hall from the University of Birmingham.

    “Models based on young stars suggest that the change in a star’s spin is consistent throughout their lifetime, which is different to what we see in these new data.”

    The team is now working on understanding how a star’s magnetic field interacts with its rotation, which may be key to solving this inconsistency.

    This kind of research could also help astronomers understand how our Sun will evolve over the next few billion years.

    “This work helps place in perspective whether or not we can expect reduced solar activity and harmful space weather in the future,” concludes co-author Guy Davies, also from the University of Birmingham.

    See the full article here .

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    U Birmingham (UK) has been challenging and developing great minds for more than a century. Characterised by a tradition of innovation, research at the University has broken new ground, pushed forward the boundaries of knowledge and made an impact on people’s lives. We continue this tradition today and have ambitions for a future that will embed our work and recognition of the Birmingham name on the international stage.

     
  • richardmitnick 1:27 pm on January 25, 2021 Permalink | Reply
    Tags: "Starquake Observations Near Their Teenage Years", , Asteroseismologists study stellar oscillations in the form of tiny waves that ripple within a star and across its surface., Asteroseismology, Kepler allowed us to study long timeframes. We could not do that by any other means., ,   

    From “Physics”: “Starquake Observations Near Their Teenage Years” 

    About Physics

    From “Physics”

    January 21, 2021
    Katherine Wright

    1
    Researchers can use waves traveling through a star to understand the properties of the star’s interior. Credit: Gabriel Perez Diaz/Instituto de Astrofisica de Canarias (ES).

    An observational target for more than a century, researchers have only very recently spotted “starquakes”—periodic fluctuations in brightness that can reveal secrets about a star’s interior.

    Conny Aerts knew she was playing the long game when, in the 1990s, she started her career in asteroseismology—a field that aims to understand the internal structure of stars through variations in their luminosity. At the time, the phenomenon was mainly explorable theoretically, but that changed dramatically in 2009 when NASA’s Kepler mission launched.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018.

    Designed to find exoplanets, the spacecraft could also collect the stellar brightness data that Aerts, who works at KU Leuven in Belgium, and others had long sought to study. In a paper published today in Reviews of Modern Physics, Aerts outlines the major achievements of the field’s first decade as an observational science and the hopes for its future.

    Asteroseismologists study stellar oscillations in the form of tiny waves that ripple within a star and across its surface. These wave phenomena—or “good vibrations” as Beach-Boy-fan Aerts calls them—have a variety of sources including the boiling of a star’s outer gas layers and the gravitational tugging of nearby planets or stars. The oscillations usually go by the term “starquakes” because of their resemblance to seismic waves that reverberate across the Earth. It is this resemblance that gave Aerts and others the hope that they could use starquakes to understand the swirling plasma inside stars—just as seismiologists use earthquakes to probe our planet’s rocky interior. But until Kepler’s arrival in 2009, asteroseismologists’ plans were foiled either by Earth’s atmosphere or by short mission durations.

    The waves from a starquake cause the stellar surface to swell and contract, causing its light output to increase or decrease by a tiny amount. Astronomers on Earth are forced to look for those changes through an atmosphere that also fluctuates in its opacity. Those atmospheric fluctuations are thousands of times bigger than the one-part-in-a-million brightness changes caused by starquakes, making starquakes extremely hard to observe using ground-based telescopes. The Kepler telescope—which breached the atmosphere—changed that. “All of a sudden we had new eyes,” Aerts says. “We could see what was happening.”

    During its four-year mission, Kepler tracked the brightness changes of over 200,000 stars. Those observations allowed researchers to unravel starquake behaviors with different periods, from the roughly minute-spaced rhythms of Sun-like stars to the day-long cycles of heavier stars. Hundreds of quakes may be rippling through a star at any one time, which, along with other factors, can mean the overall beating pattern of a large star can take years to repeat, Aerts says. “Kepler allowed us to study long timeframes. We could not do that by any other means.”

    The data have thrown up surprises, the main one being that the theories of stellar rotation did not match observations. The general picture was that as a star ages, the outer layers of its gas expand and the inner layers contract, causing the core to rotate faster. The data confirmed this trend—finding faster core rotation in older stars compared to younger ones, but the measured spin-up was 10 to 100 times slower than theories predicted. This mismatch had implications for models of how chemical species mix inside a star and for expectations of a star’s lifetime. “We hadn’t anticipated that our theory could be so wrong,” Aerts says. “For me, finding that problem was the biggest achievement of the field in the last ten years.”

    The reasons behind the mismatch have yet to be fully understood, but Aerts and others hope that some of the missing pieces will be filled in by other missions, such as NASA’s TESS, which is currently orbiting Earth, and the European Space Agency’s PLATO, which is expected to launch at the end of 2026.

    NASA/MIT Tess in the building.


    NASA/MIT TESS replaced Kepler in search for exoplanets.

    ESA PLATO spacecraft depiction

    Unlike TESS and Kepler, PLATO is specifically designed to collect starquake data and—for at least two years—will capture the brightness data every 32 seconds (as compared to 30 minutes for Kepler) for tens of thousands of stars, allowing researchers to study quakes in a wider mass range of stars. “Our field has a very bright future,” Aerts says. Saskia Hekker, an astrophysicist at the University of Heidelberg and the Heidelberg Institute for Theoretical Studies, both in Germany, agrees. Even without future data, she notes that researchers have barely scratched the surface on the asteroseismology information contained in the Kepler and TESS data. “There is still so much to be learned,” she says.

    See the full article here .

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    Stem Education Coalition

    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments (physics@aps.org).

     
  • richardmitnick 12:00 pm on June 14, 2020 Permalink | Reply
    Tags: "Las Cumbres Observatory Robotic Telescopes Provide Vital Data for Recent Astronomical Discoveries", Asteroseismology, , , , , Las Cumbres Observatory Global Telescope Network   

    From Las Cumbres Observatory Global Telescope Network: “Las Cumbres Observatory Robotic Telescopes Provide Vital Data for Recent Astronomical Discoveries” 

    LCOGT bloc

    From Las Cumbres Observatory Global Telescope Network

    1
    LCO 2m and 1m telescope enclosures at Siding Spring Observatory in Australia.

    While many telescopes around the world have been closed during the COVID-19 pandemic, Las Cumbres Observatory has continued to operate their global network of robotic telescopes where it is safe and allowed to do so. Traditional telescopes can be dangerous for humans during a pandemic because they rely on astronomers to travel to the facility and on teams of human operators and engineers working together in sometimes close quarters. In contrast, robotic facilities operate with no human intervention, except astronomers submitting new observations over the internet, and occasional software and hardware maintenance.

    “Las Cumbres Observatory is fortunate to be able to continue to provide rich data to scientists around the world during these challenging times,” said Lisa Storrie-Lombardi, the President and Observatory Director. LCO observations are featured in several recent discoveries.

    A study led by Tim Bedding of the University of Sydney, using data from NASA’s Transiting Exoplanet Survey Satellite (TESS) in conjunction with LCO, was published on May 14 in Nature.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The study showed that certain types of stars slightly more massive than the Sun, known as delta Scuti stars, pulsate with previously unknown frequencies. This solves a longstanding mystery, and will allow scientists to learn about their interiors by studying their pulsations through asteroseismology, analogous to how seismologists can learn about the Earth’s interior from studying Earthquakes. While NASA’s TESS satellite is sensitive to small stellar pulsations, it can’t split the star’s like up into a spectrum (a rainbow), which can provide complementary information. That was the job of LCO’s robotic NRES spectrographs.

    2
    Artist’s impression of a Delta Scuti pulsating star, courtesy NASA Goddard Space Flight Center. The stars rotate so rapidly that they are slightly flattened.

    On May 26, the University of Hawai’i announced that the Asteroid Terrestrial-Impact Last Alert System (ATLAS) had discovered an unusual comet.

    ATLAS telescope, First Asteroid Terrestrial-impact Last Alert system (ATLAS) fully operational 8/15/15 Haleakala , Hawaii, USA, Altitude 4,205 m (13,796 ft)

    Recent data have shown that the Jupiter Trojan object 2019 LD2 is in fact a comet with an unusual orbit. The ATLAS discovery was confirmed with follow-up observations by the LCO network. The object was reclassified from an asteroid to a comet by the Minor Planet Center, as its orbit is unstable compared to Jupiter Trojans and it has a distinctive tail. Observations of this rare comet are continuing.

    3
    (Left) ATLAS image of P/2019 LD2 (indicated by two red lines) is almost lost in the field of stars, courtesy University of Hawai’i.

    A study led by Monash University in Australia has observed, for the first time, the full process of an accreting neutron star reaching an x-ray outburst. While the process was previously thought to take place over 3 or 4 days, the new study revealed activity over 12 days. LCO provided rapid ground-based observations, while telescopes in space, like NASA’s Swift satellite, and the NICER instrument on the International Space Station provided ultraviolet and X-ray data that cannot be taken from Earth.

    NASA Neil Gehrels Swift Observatory

    NASA/NICER on the ISS

    4
    An accreting pulsar, courtesy NASA/JPL-Caltech.

    See the full article here.

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    Please help promote STEM in your local schools.

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    LCOGT Las Cumbres Observatory Global Telescope Network

    Las Cumbres Observatory Global Telescope Network is an integrated set of robotic telescopes, distributed around the world. The network currently includes two 2-meter telescopes, sited in Hawaii and eastern Australia, nine 1-meter telescopes, sited in Chile, South Africa, eastern Australia, and Texas, and three 0.4-meter telescopes, sited in Chile and the Canary Islands.

    LCOGT map

     
  • richardmitnick 1:59 pm on May 21, 2020 Permalink | Reply
    Tags: "New gravitational-wave model can bring neutron stars into even sharper focus", Asteroseismology, , , ,   

    From University of Birmingham UK via phys.org: “New gravitational-wave model can bring neutron stars into even sharper focus” 

    From University of Birmingham UK

    via


    phys.org

    May 21, 2020

    1
    The results from a numerical relativity simulation of two merging neutron stars similar to GW170817. Credit: University of Birmingham

    Gravitational-wave researchers at the University of Birmingham have developed a new model that promises to yield fresh insights into the structure and composition of neutron stars.

    The model shows that vibrations, or oscillations, inside the stars can be directly measured from the gravitational-wave signal alone. This is because neutron stars will become deformed under the influence of tidal forces, causing them to oscillate at characteristic frequencies, and these encode unique information about the star in the gravitational-wave signal.

    This makes asteroseismology—the study of stellar oscillations—with gravitational waves from colliding neutron stars a promising new tool to probe the elusive nature of extremely dense nuclear matter.

    Neutron stars are the ultradense remnants of collapsed massive stars. They have been observed in the thousands in the electromagnetic spectrum and yet little is known about their nature. Unique information can be gleaned through measuring the gravitational waves emitted when two neutron stars meet and form a binary system. First predicted by Albert Einstein, these ripples in spacetime were first detected by the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO) in 2015.

    By utilising the gravitational wave signal to measure the oscillations of the neutron stars, researchers will be able to discover new insights into the interior of these stars. The study is published in Nature Communications.

    Dr. Geraint Pratten, of the University of Birmingham’s Gravitational Wave Institute, is lead author of the study. He explained: “As the two stars spiral around each other, their shapes become distorted by the gravitational force exerted by their companion. This becomes more and more pronounced and leaves a unique imprint in the gravitational wave signal.

    “The tidal forces acting on the neutron stars excite oscillations inside the star giving us insight into their internal structure. By measuring these oscillations from the gravitational-wave signal, we can extract information about the fundamental nature and composition of these mysterious objects that would otherwise be inaccessible.”

    The model developed by the team enables the frequency of these oscillations to be determined directly from gravitational-wave measurements for the first time. The researchers used their model on the first observed gravitational-wave signal from a binary neutron star merger—GW170817.

    Co-lead author, Dr. Patricia Schmidt, added: “Almost three years after the first gravitational-waves from a binary neutron star were observed, we are still finding new ways to extract more information about them from the signals. The more information we can gather by developing ever more sophisticated theoretical models, the closer we will get to revealing the true nature of neutron stars.”

    Next generation gravitational wave observatories planned for the 2030s, will be capable of detecting far more binary neutron stars and observing them in much greater detail than is currently possible. The model produced by the Birmingham team will make a significant contribution to this science.

    “The information from this initial event was limited as there was quite a lot of background noise that made the signal difficult to isolate,” says Dr. Pratten. “With more sophisticated instruments we can measure the frequencies of these oscillations much more precisely and this should start to yield some really interesting insights.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Birmingham has been challenging and developing great minds for more than a century. Characterised by a tradition of innovation, research at the University has broken new ground, pushed forward the boundaries of knowledge and made an impact on people’s lives. We continue this tradition today and have ambitions for a future that will embed our work and recognition of the Birmingham name on the international stage.

     
  • richardmitnick 4:35 pm on January 13, 2020 Permalink | Reply
    Tags: "The Interiors of Stars", Asteroseismology, , , , , , , Improving our understanding of the interiors of intermediate mass stars.   

    From Harvard-Smithsonian Center for Astrophysics: “The Interiors of Stars” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    January 10, 2020

    1
    An illustration of vibration modes in the Sun. Astronomers have used the TESS mission to study for the first time stellar oscillations in intermeidate mass stars.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    Kosovichev et al., Structure and Rotation of the Solar Interior: Initial Results from the MDI Medium-L Program [Springer]

    _________________________________________________________

    The interiors of stars are largely mysterious regions because they are so difficult to observe. Our lack of understanding about the physical processes there, like rotation and the mixing of hot gas, introduces considerable ambuguity about how stars shine and how they evolve. Stellar oscillations, detected through brightness fluctuations, offer one way to probe these subsurface regions. In the Sun, these vibrations are due to pressure waves generated by turbulence in its outer layers (the layers dominated by convective gas motions). Helioseismology is the name given to the study of these oscillations in the Sun, and asteroseismology is the term used for the same study in other stars.

    Astronomers have long detected strong brightness variations in other stars, for example the class of Cepheid variable stars used to calibrate the cosmic distance scale, but the small, solar-like oscillations driven by convection near the star’s surface are much harder to see. Over the past few decades, space telescopes have successfully applied astroseismology to solar-type stars spanning many stages of stellar life. CfA astronomer Dave Latham was a member of a large team of astronomers who used the new TESS (Transiting Exoplanet Survey Satellite) datasets to study the interiors of the class of intermediate mass stars known as δ Sct and γ Dor stars. These stars are more massive than the Sun but not large enough to burn through their hydrogen fuel very rapidly and die as supernovae. Pulsations generally arise principally from one of two processes, those dominated by pressure (where the gas pressure restores perturbations) or by gravity (where buoyancy does). In these intermediate-mass stars both of these processes can be important, with pulsations having typical periods of roughly about six hours. The complexity of the combined processes, among other things, results in these intermediate-mass stars coming in a veritable zoo of variability types, and this variety offers astronomers more ways to test models of stellar interiors.

    The astronomers analyzed TESS data on 117 of these stars using observations taken every two minutes; accurate distances to the stars (and hence accurate luminosities) were obtained from Gaia satellite measurements.

    ESA/GAIA satellite

    The team was able for the first time to fully test and successfully refine models of pulsation for these stars. They found, for example, that gas mixing in the outer envelope plays an important role. They also spotted many higher-frequency pulsators, thereby identifying promising targets for future studies. Not least, they showed that the TESS mission has enormous potential not just for studying exoplanets, but also for improving our understanding the interiors of intermediate mass stars.

    Science paper:
    The First View of δ Scuti and γ Doradus Stars with the TESS Mission,
    MNRAS

    See the full article here .


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    Please help promote STEM in your local schools.

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 2:39 pm on December 6, 2019 Permalink | Reply
    Tags: "New clues to the Milky Way’s age", , Asteroseismology, , , , ,   

    From COSMOS Magazine: “New clues to the Milky Way’s age” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    06 December 2019

    Star-quake vibrations suggest ‘thick disc’ is 10 billion years old.

    1
    Infrared cameras reveal the stars of the crowded galactic centre region of the Milky Way.
    Credit: NASA

    2
    Credit: NASA/JPL Caltech/R.Hurt/SSC

    The Milky Way’s “thick disc” is about 10 billion years old, according to an international team of scientists.

    They used data from NASA’s now-defunct Kepler space telescope to study star-quake vibrations – and appear to have cleared up a long-standing mystery.

    “Earlier data about the age distribution of stars in the disc didn’t agree with the models constructed to describe it, but no one knew where the error lay – in the data or the models,” says Sanjib Sharma from Australia’s ARC Centre of Excellence for All Sky Astrophysics in Three Dimensions (ASTRO-3D).

    “Now we’re pretty sure we’ve found it.”

    Sharma is lead author of a paper published in the Monthly Notices of the Royal Astronomical Society. He worked with 37 other researchers from Australia, the US, Germany, Austria, Italy, Denmark, Slovenia and Sweden.

    The Milky Way – like many spiral galaxies – consists of two disc-like structures.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt. The bar is visible in this image

    The thick disc contains only about 20% of the galaxy’s stars and, based on its vertical puffiness and composition, is thought to be the older.

    To find out just how much older, Sharma and colleagues used asteroseismology – a way of identifying the internal structures of stars by measuring their oscillations from star quakes.

    “The frequencies produced tell us things about the stars’ internal properties, including their age,” says ASTRO-3D’s Dennis Stello. “It’s a bit like identifying a violin as a Stradivarius by listening to the sound it makes.”

    The researchers don’t “hear” the sound generated by star-quakes. Instead, they look for how the internal movement is reflected in changes to brightness.

    “Stars are just spherical instruments full of gas,” says Sharma, “but their vibrations are tiny, so we have to look very carefully.

    “The exquisite brightness measurements made by Kepler were ideal for that. The telescope was so sensitive it would have been able to detect the dimming of a car headlight as a flea walked across it.”

    The data delivered by the telescope during the four years after it launched in 2009 presented a problem. It suggested there were more younger stars in the thick disc than models predicted.

    The question confronting astronomers was stark: were the models wrong, or was the data incomplete?

    In 2013, however, Kepler broke down, and NASA reprogrammed it to continue working on a reduced capacity – a period that became known as the K2 mission. The project involved observing many different parts of the sky for 80 days at a time.

    This allowed for a fresh spectroscopic analysis. This revealed that the chemical composition incorporated in the existing models for stars in the thick disc was wrong, which affected the prediction of their ages.

    Taking this into account, the researchers found that the observed asteroseismic data now fell into “excellent agreement” with model predictions.

    See the full article here .


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  • richardmitnick 4:44 pm on April 1, 2019 Permalink | Reply
    Tags: Asteroseismology, , , , , , , The planet TOI 197.01 (TOI is short for “TESS Object of Interest”)   

    From Iowa State University: “Data flows from NASA’s TESS Mission, leads to discovery of Saturn-sized planet” 

    From Iowa State University

    Mar 27, 2019

    Steve Kawaler
    Physics and Astronomy
    515-294-9728
    sdk@iastate.edu

    Mike Krapfl
    News Service
    515-294-4917
    mkrapfl@iastate.edu

    1
    A “hot Saturn” passes in front of its host star in this illustration. Astronomers who study stars used “starquakes” to characterize the star, which provided critical information about the planet. See a video illustration of the planet orbiting the star. llustration by Gabriel Perez Diaz, Instituto de Astrofísica de Canarias.

    Astronomers who study stars are providing a valuable assist to the planet-hunting astronomers pursuing the primary objective of NASA’s new TESS Mission.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    In fact, asteroseismologists – stellar astronomers who study seismic waves (or “starquakes”) in stars that appear as changes in brightness – often provide critical information for finding the properties of newly discovered planets.

    This teamwork enabled the discovery and characterization of the first planet identified by TESS for which the oscillations of its host star can be measured.

    The planet – TOI 197.01 (TOI is short for “TESS Object of Interest”) – is described as a “hot Saturn” in a recently accepted scientific paper [The Astronomical Journal by an international team of 141 astronomers. Daniel Huber, an assistant astronomer at the University of Hawaii at Manoa’s Institute for Astronomy, is the lead author of the paper. Steve Kawaler, a professor of physics and astronomy; and Miles Lucas, an undergraduate student, are co-authors from Iowa State University.]. That’s because the planet is about the same size as Saturn and is also very close to its star, completing an orbit in just 14 days, and therefore very hot.

    “This is the first bucketful of water from the firehose of data we’re getting from TESS,” Kawaler said.

    TESS – the Transiting Exoplanet Survey Satellite, led by astrophysicists from the Massachusetts Institute of Technology – launched from Florida’s Cape Canaveral Air Force Station on April 18, 2018. The spacecraft’s primary mission is to find exoplanets, planets beyond our solar system. The spacecraft’s four cameras are taking nearly month-long looks at 26 vertical strips of the sky – first over the southern hemisphere and then over the northern. After two years, TESS will have scanned 85 percent of the sky.

    Astronomers (and their computers) sort through the images, looking for transits, the tiny dips in a star’s light caused by an orbiting planet passing in front of it.

    Planet transit. NASA/Ames

    NASA’s Kepler Mission – a predecessor to TESS – looked for planets in the same way, but scanned a narrow slice of the Milky Way galaxy and focused on distant stars.

    TESS is targeting bright, nearby stars, allowing astronomers to follow up on its discoveries using other space and ground observations to further study and characterize stars and planets. In another paper recently published online by The Astrophysical Journal Supplement Series, astronomers from the TESS Asteroseismic Science Consortium (TASC) identified a target list of sun-like oscillating stars (many that are similar to our future sun) to be studied using TESS data – a list featuring 25,000 stars.

    Kawaler – who witnessed the launch of Kepler in 2009, and was in Florida for the launch of TESS (but a last-minute delay meant he had to miss liftoff to return to Ames to teach) – is on the seven-member TASC Board. The group is led by Jørgen Christensen-Dalsgaard of Aarhus University in Denmark.

    TASC astronomers use asteroseismic modeling to determine a host star’s radius, mass and age. That data can be combined with other observations and measurements to determine the properties of orbiting planets.

    In the case of host star TOI-197, the asteroseismolgists used its oscillations to determine it’s about 5 billion years old and is a little heavier and larger than the sun. They also determined that planet TOI-197.01 is a gas planet with a radius about nine times the Earth’s, making it roughly the size of Saturn. It’s also 1/13th the density of Earth and about 60 times the mass of Earth.

    Those findings say a lot about the TESS work ahead: “TOI-197 provides a first glimpse at the strong potential of TESS to characterize exoplanets using asteroseismology,” the astronomers wrote in their paper.

    Kawaler is expecting that the flood of data coming from TESS will also contain some scientific surprises.

    “The thing that’s exciting is that TESS is the only game in town for a while and the data are so good that we’re planning to try to do science we hadn’t thought about,” Kawaler said. “Maybe we can also look at the very faint stars – the white dwarfs – that are my first love and represent the future of our sun and solar system.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Iowa State University is a public, land-grant university, where students get a great academic start in learning communities and stay active in 800-plus student organizations, undergrad research, internships and study abroad. They learn from world-class scholars who are tackling some of the world’s biggest challenges — feeding the hungry, finding alternative fuels and advancing manufacturing.

    Iowa Agricultural College and Model Farm (now Iowa State University) was officially established on March 22, 1858, by the legislature of the State of Iowa. Story County was selected as a site on June 21, 1859, and the original farm of 648 acres was purchased for a cost of $5,379. The Farm House, the first building on the Iowa State campus, was completed in 1861, and in 1862, the Iowa legislature voted to accept the provision of the Morrill Act, which was awarded to the agricultural college in 1864.

    Iowa State University Knapp-Wilson Farm House. Photo between 1911-1926

    Iowa Agricultural College (Iowa State College of Agricultural and Mechanic Arts as of 1898), as a land grant institution, focused on the ideals that higher education should be accessible to all and that the university should teach liberal and practical subjects. These ideals are integral to the land-grant university.

    The first official class entered at Ames in 1869, and the first class (24 men and 2 women) graduated in 1872. Iowa State was and is a leader in agriculture, engineering, extension, home economics, and created the nation’s first state veterinary medicine school in 1879.

    In 1959, the college was officially renamed Iowa State University of Science and Technology. The focus on technology has led directly to many research patents and inventions including the first binary computer (the ABC), Maytag blue cheese, the round hay baler, and many more.

    Beginning with a small number of students and Old Main, Iowa State University now has approximately 27,000 students and over 100 buildings with world class programs in agriculture, technology, science, and art.

    Iowa State University is a very special place, full of history. But what truly makes it unique is a rare combination of campus beauty, the opportunity to be a part of the land-grant experiment, and to create a progressive and inventive spirit that we call the Cyclone experience. Appreciate what we have here, for it is indeed, one of a kind.

     
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