Tagged: NASA Goddard Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 7:42 am on March 25, 2017 Permalink | Reply
    Tags: , , , NASA Goddard,   

    From Goddard: “OSIRIS-REx asteroid search tests instruments, science team” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    March 24, 2017
    Erin Morton
    morton@orex.lpl.arizona.edu
    University of Arizona, Tucson

    Nancy Neal Jones
    nancy.n.jones@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    The path of the Main Belt asteroid 12 Victoria, as imaged by NASA’s OSIRIS-REx spacecraft on Feb. 11, 2017, during the mission’s Earth-Trojan Asteroid Search. This animation is made of a series of five images taken by the spacecraft’s MapCam camera that were then cropped and centered on Victoria. The images were taken about 51 minutes apart and each was exposed for 10 seconds. Credits: NASA/Goddard/University of Arizona


    OSIRIS-REx spacecraft

    During an almost two-week search, NASA’s OSIRIS-REx mission team activated the spacecraft’s MapCam imager and scanned part of the surrounding space for elusive Earth-Trojan asteroids — objects that scientists believe may exist in one of the stable regions that co-orbits the sun with Earth. Although no Earth-Trojans were discovered, the spacecraft’s camera operated flawlessly and demonstrated that it could image objects two magnitudes dimmer than originally expected.

    The spacecraft, currently on its outbound journey to the asteroid Bennu, flew through the center of Earth’s fourth Lagrangian area — a stable region 60 degrees in front of Earth in its orbit where scientists believe asteroids may be trapped, such as asteroid 2010 TK7 discovered by NASA’s Wide-field Infrared Survey Explorer (WISE) satellite in 2010. Though no new asteroids were discovered in the region that was scanned, the spacecraft’s cameras MapCam and PolyCam successfully acquired and imaged Jupiter and several of its moons, as well as Main Belt asteroids.

    “The Earth-Trojan Asteroid Search was a significant success for the OSIRIS-REx mission,” said OSIRIS-REx Principal Investigator Dante Lauretta of the University of Arizona, Tucson. “In this first practical exercise of the mission’s science operations, the mission team learned so much about this spacecraft’s capabilities and flight operations that we are now ahead of the game for when we get to Bennu.”

    The Earth Trojan survey was designed primarily as an exercise for the mission team to rehearse the hazard search the spacecraft will perform as it approaches its target asteroid Bennu. This search will allow the mission team to avoid any natural satellites that may exist around the asteroid as the spacecraft prepares to collect a sample to return to Earth in 2023 for scientific study.

    The spacecraft’s MapCam imager, in particular, performed much better than expected during the exercise. Based on the camera’s design specifications, the team anticipated detecting four Main Belt asteroids. In practice, however, the camera was able to detect moving asteroids two magnitudes fainter than expected and imaged a total of 17 Main Belt asteroids. This indicates that the mission will be able to detect possible hazards around Bennu earlier and from a much greater distance that originally planned, further reducing mission risk.

    Scientists are still analyzing the implications of the search’s results for the potential population of Earth-Trojan asteroids and will publish conclusions after a thorough study of mission data.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s observation planning and processing. Lockheed Martin Space Systems in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the agency’s New Frontiers Program for its Science Mission Directorate in Washington.

    For more information on OSIRIS-REx, visit:

    http://www.nasa.gov/osirisrex and http://www.asteroidmission.org

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 9:24 am on March 20, 2017 Permalink | Reply
    Tags: , , , , Equinox, Lunar Eclipse, NASA Goddard, NASA Satellites Ready When Stars and Planets Align, Solar Eclipse, Solstice, , Transits   

    From Goddard: “NASA Satellites Ready When Stars and Planets Align” A NASA Tour de Force 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    March 17, 2017
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    No image caption. No image credit

    The movements of the stars and the planets have almost no impact on life on Earth, but a few times per year, the alignment of celestial bodies has a visible effect. One of these geometric events — the spring equinox — is just around the corner, and another major alignment — a total solar eclipse — will be visible across America on Aug. 21, with a fleet of NASA satellites viewing it from space and providing images of the event.

    To understand the basics of celestial alignments, here is information on equinoxes, solstices, full moons, eclipses and transits:

    Equinox

    Earth spins on a tilted axis. As our planet orbits around the sun, that tilt means that during half of the year, the Northern Hemisphere receives more daylight — its summertime — and during the other half of the year, the Southern Hemisphere does. Twice a year, Earth is in just the right place so that it’s lined up with respect to the sun, and both hemispheres of the planet receive the same amount of daylight. On these days, there are almost equal amounts of day and night, which is where the word equinox — meaning “equal night” in Latin — comes from. The equinox marks the onset of spring with a transition from shorter to longer days for half the planet, along with more direct sunlight as the sun rises higher above the horizon. In 2017, in the Northern Hemisphere, the spring equinox occurs on March 20. Six months later, fall begins with the autumnal equinox on Sept. 22.

    2
    During the equinoxes, both hemispheres receive equal amounts of daylight. Image not to scale. Credits: NASA’s Goddard Space Flight Center/Genna Duberstein

    Solstice

    As Earth continues along in its orbit after the equinox, it eventually reaches a point where its tilt is at the greatest angle to the plane of its orbit — and the point where one half of the planet is receiving the most daylight and the other the least. This point is the solstice — meaning “sun stands still” in Latin — and it occurs twice a year. These days are our longest and shortest days, and mark the change of seasons to summer and winter.

    3
    During the solstices, Earth reaches a point where its tilt is at the greatest angle to the plane of its orbit, causing one hemisphere to receive more daylight than the other. Image not to scale.
    Credits: NASA’s Goddard Space Flight Center/Genna Duberstein

    Full Moon and New Moon

    As Earth goes around the sun, the moon is also going around Earth. There is a point each month when the three bodies align with Earth between the sun and the moon. During this phase, viewers on Earth can see the full face of the moon reflecting light from the sun — a full moon. The time between full moons is about four weeks — 29.5 days to be exact. Halfway between full moons, the order of the three bodies reverses and the moon lies between the sun and Earth. During this time, we can’t see the moon reflecting the sun’s light, so it appears dark. This is the new moon.

    4
    When the moon’s orbit around Earth lines up on the same plane as Earth’s orbit around the sun, its shadow is cast across the planet. Image not to scale. Credits: NASA’s Goddard Space Flight Center/Genna Duberstein

    Lunar Eclipse

    Sometimes, during a full moon, Earth lines up perfectly between the moon and the sun, so its shadow is cast on the moon. From Earth’s viewpoint, we see a lunar eclipse. The plane of the moon’s orbit around Earth isn’t precisely aligned with the plane of the Earth’s orbit around the sun so on most months we don’t see an eclipse. The next lunar eclipse — which will be visible throughout much of Asia, Europe, Africa and Australia — will occur on Aug. 7.

    5
    When the moon falls completely in Earth’s shadow, a total lunar eclipse occurs. Only light travelling through Earth’s atmosphere, which is bent into the planet’s shadow, is reflected off
    the moon, giving it a reddish hue. Image not to scale. Credits: NASA’s Goddard Space Flight Center/Genna Duberstein

    Solar Eclipse

    A solar eclipse happens when the moon blocks our view of the sun. This can only happen at a new moon, when the moon’s orbit positions it between the sun and Earth — but this doesn’t happen every month. As mentioned above, the plane of the moon’s orbit around Earth isn’t precisely aligned with the plane of the Earth’s orbit around the sun so, from Earth’s view, on most months we see the moon passing above or below the sun. A solar eclipse happens only on those new moons where the alignment of all three bodies are in a perfectly straight line.

    When the moon blocks all of the sun’s light, a total eclipse occurs, but when the moon is farther away — making it appear smaller from our vantage point on Earth — it blocks most, but not all of the sun. This is called an annular eclipse, which leaves a ring of the sun’s light still visible from around the moon. This alignment usually occurs every year or two, but is only visible from a small area on Earth.

    On Aug. 21, a total solar eclipse will move across America. While lunar eclipses are visible from entire hemispheres of Earth, a total solar eclipse is visible only from a narrow band along Earth’s surface. Since this eclipse will take about an hour and a half to cross an entire continent, it is particularly important scientifically, as it allows observations from many places for an extended duration of time. NASA has funded 11 projects to take advantage of the 2017 eclipse and study its effects on Earth as well as study the sun’s atmosphere.

    6
    When the moon’s orbit around Earth lines up on the same plane as Earth’s orbit around the sun, its shadow is cast across the planet. Image not to scale. Credits: NASA’s Goddard Space Flight Center/Genna Duberstein

    Transits


    Planet transit. NASA/Ames

    An eclipse is really just a special kind of transit — which is when any celestial body passes in front of another. From Earth we are able to watch transits such as Mercury and Venus passing in front of the sun. But such transits also offer a way to spot new distant worlds. When a planet in another star system passes in front of its host star, it blocks some of the star’s light — making it appear slightly dimmer. By watching for changes in the amount of light over time, we can deduce the presence of a planet. This method has been used to discover thousands of planets, including the TRAPPIST-1 planets.

    7
    The seven planets that orbit the Trappist-1 star, in order of their distance from the star, compared to Earth’s solar system. https://www.thestar.com/news/world/2017/02/22/what-to-know-about-the-newly-discovered-trappist-1-solar-system.html

    8
    During a transit, a planet passes in between us and the star it orbits. This method is commonly used to find new exoplanets in our galaxy. Image not to scale.
    Credits: NASA’s Goddard Space Flight Center/Genna Duberstein

    For more information about how NASA looks at these events, visit:

    http://www.nasa.gov/sunearth

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 6:50 pm on March 7, 2017 Permalink | Reply
    Tags: , NASA Goddard, Oort cloud comet C/2014 Q2 also called Lovejoy   

    From Keck: “NASA Study Using Keck Telescope Hints at Possible Change in Water ‘Fingerprint’ of Comet” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    March 6, 2017.
    Contact:
    Elizabeth Zubritsky
    NASA Goddard Space Flight Center
    elizabeth.a.zubritsky@nasa.gov

    Rich Matsuda
    W. M. Keck Observatory
    (808) 881-3822
    communications@keck.hawaii.edu

    1
    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun. Credit: Courtesy of Damian Peach

    A trip past the sun may have selectively altered the production of one form of water in a comet – an effect not seen by astronomers before, a new NASA study suggests.

    Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.

    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.

    The team focused on Lovejoy’s water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the “D” in HDO. From these measurements, the researchers calculated the D-to-H ratio – a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system. Researchers also use the D-to-H value to try to understand how much of Earth’s water may have come from comets versus asteroids.

    The scientists compared their findings from the Keck observations with another team’s observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference: After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant. This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

    “The change we saw with this comet is surprising, and highlights the need for repeated measurements of D-to-H in comets at different positions in their orbits to understand all the implications,” said Lucas Paganini, a researcher with the Goddard Center for Astrobiology and lead author of the study, available online in the Astrophysical Journal Letters.

    Changes in the water production are expected as comets approach the sun, but previous understanding suggested that the release of these different forms of water normally rise or fall more-or-less together, maintaining a consistent D-to-H value. The new findings suggest this may not be the case.

    “If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth’s water compared to asteroids,” Paganini said, “especially, if these are based on a single measurement of the D-to-H value in cometary water.”

    The production of HDO in comets has historically been difficult to measure, because HDO is a much less abundant form of water. Lovejoy, for example, released on the order of 1,500 times more H2O than HDO. Lovejoy’s brightness made it possible to measure HDO when the comet passed near Earth, and the improved detectors that are being installed in some ground-based telescopes will permit similar measurements in fainter comets in the future.

    The apparent change in Lovejoy’s D-to-H may be caused by the higher levels of energetic processes – such as radiation near the sun – that might have altered the characteristics of water in surface layers of the comet. In this case, a different D-to-H value might indicate that the comet has “aged” into a different stage of its lifecycle. Alternatively, prior results might have ignored possible chemical alteration occurring in the comet’s tenuous atmosphere.

    “Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun,” said Michael Mumma, director of the Goddard Center for Astrobiology and a co-author of the study. “The infrared technique provides a snapshot of the comet’s output by measuring the production of H2O and HDO simultaneously. This is especially important because it eliminates many sources of systematic uncertainty.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

     
  • richardmitnick 9:45 am on March 1, 2017 Permalink | Reply
    Tags: , Basic, NASA Goddard, NASA Study Hints at Possible Change in Water ‘Fingerprint’ of Comet   

    From Goddard: “NASA Study Hints at Possible Change in Water ‘Fingerprint’ of Comet” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Feb. 28, 2017
    Elizabeth Zubritsky
    elizabeth.a.zubritsky@nasa.gov
    NASA’s Goddard Space Flight Center in Greenbelt, Md.

    A trip past the sun may have selectively altered the production of one form of water in a comet – an effect not seen by astronomers before, a new NASA study suggests.

    Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.

    1
    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.
    Credits: Courtesy of Damian Peach

    The team focused on Lovejoy’s water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the “D” in HDO. From these measurements, the researchers calculated the D-to-H ratio – a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system. Researchers also use the D-to-H value to try to understand how much of Earth’s water may have come from comets versus asteroids.

    The scientists compared their findings from the Keck observations with another team’s observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference: After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant. This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

    “The change we saw with this comet is surprising, and highlights the need for repeated measurements of D-to-H in comets at different positions in their orbits to understand all the implications,” said Lucas Paganini, a researcher with the Goddard Center for Astrobiology and lead author of the study, available online in the Astrophysical Journal Letters.

    Changes in the water production are expected as comets approach the sun, but previous understanding suggested that the release of these different forms of water normally rise or fall more-or-less together, maintaining a consistent D-to-H value. The new findings suggest this may not be the case.

    “If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth’s water compared to asteroids,” Paganini said, “especially, if these are based on a single measurement of the D-to-H value in cometary water.”

    The production of HDO in comets has historically been difficult to measure, because HDO is a much less abundant form of water. Lovejoy, for example, released on the order of 1,500 times more H2O than HDO. Lovejoy’s brightness made it possible to measure HDO when the comet passed near Earth, and the improved detectors that are being installed in some ground-based telescopes will permit similar measurements in fainter comets in the future.

    The apparent change in Lovejoy’s D-to-H may be caused by the higher levels of energetic processes – such as radiation near the sun – that might have altered the characteristics of water in surface layers of the comet. In this case, a different D-to-H value might indicate that the comet has “aged” into a different stage of its lifecycle. Alternatively, prior results might have ignored possible chemical alteration occurring in the comet’s tenuous atmosphere.

    “Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun,” said Michael Mumma, director of the Goddard Center for Astrobiology and a co-author of the study. “The infrared technique provides a snapshot of the comet’s output by measuring the production of H2O and HDO simultaneously. This is especially important because it eliminates many sources of systematic uncertainty.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 4:16 pm on February 28, 2017 Permalink | Reply
    Tags: GOES-16 SUVI instrument, NASA Goddard, , NOAA’s GOES-16 satellite,   

    From NOAA and Goddard: “First Solar Images from NOAA’s GOES-16 Satellite” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    1

    NOAA

    Feb. 27, 2017

    Michelle Smith
    National Oceanic and Atmospheric Administration, Silver Spring, Md.
    michelle.smith@nasa.gov

    Rob Gutro
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    Robert.j.gutro@nasa.gov

    The first images from the Solar Ultraviolet Imager or SUVI instrument aboard NOAA’s GOES-16 satellite have been successful, capturing a large coronal hole on Jan. 29, 2017.

    NOAA GOES-16
    NOAA GOES-16

    The sun’s 11-year activity cycle is currently approaching solar minimum, and during this time powerful solar flares become scarce and coronal holes become the primary space weather phenomena – this one in particular initiated aurora throughout the polar regions. Coronal holes are areas where the sun’s corona appears darker because the plasma has high-speed streams open to interplanetary space, resulting in a cooler and lower-density area as compared to its surroundings.


    Access mp4 video here .
    This animation from January 29, 2017, shows a large coronal hole in the sun’s southern hemisphere from the Solar Ultraviolet Imager (SUVI) on board NOAA’s new GOES-16 satellite. SUVI observations of solar flares and solar eruptions will provide an early warning of possible impacts to Earth’s space environment and enable better forecasting of potentially disruptive events on the ground. This animation captures the sun in the 304 Å wavelength, which observes plasma in the sun’s atmosphere up to a temperature of about 50,000 degrees. When combined with the five other wavelengths from SUVI, observations such as these give solar physicists and space weather forecasters a complete picture of the conditions on the sun that drive space weather. Credits: NOAA/NASA

    SUVI is a telescope that monitors the sun in the extreme ultraviolet wavelength range. SUVI will capture full-disk solar images around-the-clock and will be able to see more of the environment around the sun than earlier NOAA geostationary satellites.

    The sun’s upper atmosphere, or solar corona, consists of extremely hot plasma, an ionized gas. This plasma interacts with the sun’s powerful magnetic field, generating bright loops of material that can be heated to millions of degrees. Outside hot coronal loops, there are cool, dark regions called filaments, which can erupt and become a key source of space weather when the sun is active. Other dark regions are called coronal holes, which occur where the sun’s magnetic field allows plasma to stream away from the sun at high speed. The effects linked to coronal holes are generally milder than those of coronal mass ejections, but when the outflow of solar particles is intense – can pose risks to satellites in Earth orbit.

    The solar corona is so hot that it is best observed with X-ray and extreme-ultraviolet (EUV) cameras. Various elements emit light at specific EUV and X-ray wavelengths depending on their temperature, so by observing in several different wavelengths, a picture of the complete temperature structure of the corona can be made. The GOES-16 SUVI observes the sun in six EUV channels.

    Data from SUVI will provide an estimation of coronal plasma temperatures and emission measurements which are important to space weather forecasting. SUVI is essential to understanding active areas on the sun, solar flares and eruptions that may lead to coronal mass ejections which may impact Earth. Depending on the magnitude of a particular eruption, a geomagnetic storm can result that is powerful enough to disturb Earth’s magnetic field. Such an event may impact power grids by tripping circuit breakers, disrupt communication and satellite data collection by causing short-wave radio interference and damage orbiting satellites and their electronics. SUVI will allow the NOAA Space Weather Prediction Center to provide early space weather warnings to electric power companies, telecommunication providers and satellite operators.

    3
    These images of the sun were captured at the same time on January 29, 2017 by the six channels on the SUVI instrument on board GOES-16 and show a large coronal hole in the sun’s southern hemisphere. Each channel observes the sun at a different wavelength, allowing scientists to detect a wide range of solar phenomena important for space weather forecasting.
    Credits: NOAA

    SUVI replaces the GOES Solar X-ray Imager (SXI) instrument in previous GOES satellites and represents a change in both spectral coverage and spatial resolution over SXI.

    NASA successfully launched GOES-R at 6:42 p.m. EST on Nov. 19, 2016, from Cape Canaveral Air Force Station in Florida and it was renamed GOES-16 when it achieved orbit. GOES-16 is now observing the planet from an equatorial view approximately 22,300 miles above the surface of Earth.

    NOAA’s satellites are the backbone of its life-saving weather forecasts. GOES-16 will build upon and extend the more than 40-year legacy of satellite observations from NOAA that the American public has come to rely upon.

    For more information about GOES-16, visit: http://www.goes-r.gov/ or http://www.nasa.gov/goes

    To learn more about the GOES-16 SUVI instrument, visit:

    http://www.goes-r.gov/spacesegment/suvi.html

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 3:05 pm on February 24, 2017 Permalink | Reply
    Tags: GRIPS - Gamma-Ray Imager/Polarimeter for Solar flares, NASA Goddard, NASA-Funded Balloon Recovered a Year After Flight Over Antarctica, Spiraling polar vortex, University of California Berkeley’s Space Science Laboratory   

    From Goddard: “NASA-Funded Balloon Recovered a Year After Flight Over Antarctica” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Feb. 23, 2017
    Lina Tran
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    For 12 days in January 2016, a football-field-sized balloon with a telescope hanging beneath it floated 24 miles above the Antarctic continent, riding the spiraling polar vortex. On Jan. 31, 2016, scientists sent the pre-planned command to cut the balloon – and the telescope parachuted to the ground in the Queen Maud region of Antarctica.

    The telescope sat on the ice for an entire year.


    Access mp4 video here .
    Watch the video to see the launch, flight and recovery of the NASA-funded GRIPS balloon. In January 2016, scientists launched GRIPS from Antarctica – and they recovered the payload from the ice one year later. GRIPS is a helium balloon-borne telescope designed to study high-energy particles generated by solar flares. Credits: NASA Goddard/UC-Berkeley/Hazel Bain/Joy Ng, producer

    The scientists did quickly recover the data vaults from the NASA-funded mission, called GRIPS, which is short for Gamma-Ray Imager/Polarimeter for Solar flares. But due to incoming winter weather – summer runs October through February in Antarctica – they had to leave the remaining instruments on the ice and schedule a recovery effort for the following year. Finally, in January 2017, it was warm and safe enough to recover the instruments.

    This process of drop and later recovery is common for such balloon missions and the telescope appears to be in good shape.

    1
    2
    3
    4
    5
    6
    7
    NASA Goddard Space Flight Center GRIPS Eyes the Sun During Antarctic Summer
    8
    NASA Goddard Space Flight Center GRIPS Launch

    “Despite sitting on the ice for a year, no snow had made it into the electronics,” said Hazel Bain, a University of California, Berkeley solar physicist on the GRIPS team. “The cryostat instrument, which houses the GRIPS detectors, seemed in great condition, and we’re hoping to use some of the instruments again.” Berkeley physics graduate student Nicole Duncan and Bain led the recovery effort.

    GRIPS is a helium balloon-borne telescope designed to study high-energy particles generated by solar flares and help scientists better understand what causes these giant eruptions on the sun, which can send energy toward our planet and shape the very nature of near-Earth space. The telescope studies these particles with three times more detail than current state-of-the-art space instruments. Each kind of solar radiation conveys unique information about the physics underlying flares. GRIPS specifically observes hard X-ray and gamma-ray emissions, which reveal the composition, abundance and dynamics of solar flare material.

    On Jan. 19, 2016, GRIPS began its flight near McMurdo Station, suspended under a giant balloon. During its flight, GRIPS observed 21 C-class, relatively low-level, solar flares. The scientists studied those observations throughout 2016, but had to wait a year to be reunited with the actual scientific instruments.

    The following Antarctic summer of January 2017, the scientists returned to Amundsen-Scott South Pole Station to recover the payload. Over the course of three one-day flights to the GRIPS landing site, about 500 miles away from the station, they successfully dug out and recovered GRIPS instruments and hardware.

    The instruments were flown back to the South Pole station, dried out and packed for shipping to McMurdo Station. The Ocean Giant, McMurdo Station’s annual resupply vessel, will return the instruments to the U.S., where they will eventually undergo testing and evaluation for potential future flights. GRIPS is a NASA-funded project largely designed, built and tested by the University of California, Berkeley’s Space Science Laboratory.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.
    NASA Goddard campus
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 10:45 am on February 20, 2017 Permalink | Reply
    Tags: , GISS global climate models over the years, NASA Goddard   

    From Goddard: “Forcings in GISS Climate Models” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    2016-02-05
    Dr. Makiko Sato
    Dr. Gavin Schmidt.

    We summarize here forcing datasets used in GISS global climate models over the years. Note that the forcings are estimates that may be revised as new information or better understandings of the source data become available. We archive both our current best estimates of the forcings, along with complete sets of forcings used in specific studies. All radiative forcings are with respect to a specified baseline (often conditions in 1850 or 1750).

    Forcings can be specified in a number of different ways. Traditionally, forcings have been categorised based on specific components in the radiative transfer calculation (concentrations of greenhouse gases, aerosols, surface albedo changes, solar irradiance, etc.). More recently, attribution of forcings have been made via specific emissions (which may have impacts on multiple atmospheric components) or by processes (such as deforestation) that impact multiple terms at once (e.g., Shindell et al., 2009).

    Additionally, the definition of how to specify a forcing can also vary. A good description of these definitions and their differences can be found in Hansen et al. (2005). Earlier studies tend to use either the instantaneous radiative imbalance at the tropopause (Fi), or very similarly, the radiative imbalance at the Top-of-the-Atmosphere (TOA) after stratospheric adjustments — the adjusted forcing (Fa). More recently, the concept of an ‘Effective Radiative Forcing’ (Fs) has become more prevalent, a definition which includes a number of rapid adjustments to the imbalance, not just the stratospheric temperatures. For some constituents, these differences are slight, but for some others (particularly aerosols) they can be significant.

    In order to compare radiative forcings, one also needs to adjust for the efficacy of the forcing relative to some standard, usually the response to increasing CO2. This is designed to adjust for particular geographical features in the forcing that might cause one forcing to trigger larger or smaller feedbacks than another. Applying the efficacies can then make the prediction of the impact of multiple forcings closely equal the net impact of all of them. This is denoted Fe in the Hansen description. Efficacies can depend on the specific context (i.e. they might be different for a very long term simulation, compared to a short term transient simulation) and don’t necessarily disappear by use of the different forcing definitions above.

    Quantifiying the actual forcing within a global climate model is quite complicated and can depend on the baseline climate state. This is therefore an additional source of uncertainty. Within a modern complex climate model, forcings other than solar are not imposed as energy flux perturbations. Rather, the flux perturbations are diagnosed after the specific physical change is made. Estimates of forcings for solar, volcanic and well-mixed GHGs derived from simpler models may be different from the effect in a GCM. Forcings from more heterogenous forcings (aerosols, ozone, land use, etc.) are most often diagnosed from the GCMs directly.
    Forcings in the CMIP5 Simulations

    1
    Fig. Instantaneous radiative forcing at the tropopause (W/m2) in the E2-R NINT ensemble. (a) Individual forcings and (b) Total forcing, along with the separate sums of natural (solar, volcanic and orbital) and anthropogenic forcings. (Updated: 3/12/2016)

    Calculations and descriptions of the forcings in the GISS CMIP5 simulations (1850-2012) can be found in Miller et al. (2014). Data for these figures are available here and here. (Note the iRF figure and values were corrected on 3/12/2016) to account for a missing forcing in the ‘all forcings’ case. Fig. 4 in Miller et al (2014) was also updated). Snapshots of the ERF (Fs) and adjusted forcings (Fa) from these simulations. Note that the forcings from 2000 (or 2005 in some cases) are extrapolations taken from the RCP scenarios, and the real world has diverged slightly from them.

    Further estimates of the responses, including temperatures and the ocean heat content changes, and efficacies are available in the supplementary material associated with Marvel et al. (2016).

    Forcings in Hansen et al. (2011)

    The following chart of forcings from 1880-2011 is taken from Hansen et al. (2011):

    4
    5

    Data is updated from the CMIP3 studies below (e.g., Hansen et al. 2007a, b) and extended to 2011 using assumptions outlined in the paper. The separate radiative forcing data (Fe) are available here (Net forcing). The figures are also available as PDFs here and here.

    Forcings in the CMIP3 simulations

    The following chart of forcings from 1750-2000 is taken from Hansen et al. (2005):

    6

    Figure is also available in PDF format. (Source: Figure 28 of Hansen et al. (2005). More details, including maps and timeseries of individual forcings are available on the Efficacy web pages.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard campus

    NASA/Goddard Campus

    NASA image

     
  • richardmitnick 6:20 pm on February 14, 2017 Permalink | Reply
    Tags: Downlink communications, Lasers Could Give Space Research its 'Broadband' Moment, NASA Goddard   

    From JPL-Caltech: “Lasers Could Give Space Research its ‘Broadband’ Moment” 

    NASA JPL Banner

    JPL-Caltech

    February 14, 2017
    Andrew Good
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-2433
    andrew.c.good@jpl.nasa.gov

    1
    Several upcoming NASA missions will use lasers to increase data transmission from space. Image Credit: NASA’s Goddard Space Flight Center/Amber Jacobson, producer

    Thought your Internet speeds were slow? Try being a space scientist for a day.

    The vast distances involved will throttle data rates to a trickle. You’re lucky if a spacecraft can send more than a few megabits per second (Mbps) — a pittance even by dial-up standards.

    But we might be on the cusp of a change. Just as going from dial-up to broadband revolutionized the Internet and made high-resolution photos and streaming video a given, NASA may be ready to undergo a similar “broadband” moment in coming years.

    The key to that data revolution will be lasers. For almost 60 years, the standard way to “talk” to spacecraft has been with radio waves, which are ideal for long distances. But optical communications, in which data is beamed over laser light, can increase that rate by as much as 10 to 100 times.

    High data rates will allow researchers to gather science faster, study sudden events like dust storms or spacecraft landings, and even send video from the surface of other planets. The pinpoint precision of laser communications is also well suited to the goals of NASA mission planners, who are looking to send spacecraft farther out into the solar system.

    “Laser technology is ideal for boosting downlink communications from deep space,” said Abi Biswas, the supervisor of the Optical Communications Systems group at NASA’s Jet Propulsion Laboratory, Pasadena, California. “It will eventually allow for applications like giving each astronaut his or her own video feed, or sending back higher-resolution, data-rich images faster.”

    ___________________________________________________________________

    NASA’s space lasers
    Past and future NASA projects involving laser communications:

    Name: Lunar Laser Communications Demonstration (LLCD)
    Led by: Goddard Space Flight Center
    Year: 2013
    Objective: Was NASA’s first system for two-way communication using a laser instead of radio waves. An error-free uplink data rate of 20 Mbps transmitted from a primary ground station in New Mexico to NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE), a spacecraft orbiting the moon. Demonstrated an error-free downlink rate of 622 Mbps — the equivalent of streaming 30 channels of HDTV from the moon.

    Name: Optical Payload for Lasercomm Science (OPALS)
    Led by: JPL
    Year: 2014
    Objective: Testing laser communications from the International Space Station. Beamed a video file every 3.5 seconds for a total of 148 seconds. With traditional downlink methods, sending the 175-megabit video just once would have taken 10 minutes.

    Name: Laser Communications Relay Demonstration (LCRD)
    Led by: Goddard Space Flight Center
    Year: 2019
    Objective: Will relay laser signals between telescopes at Table Mountain, California, and in Hawaii through a relay satellite in geostationary orbit during a two-year demonstration period. The system is designed to operate for up to five years to prove the everyday reliability of laser communications for future NASA missions.

    Name: Deep Space Optical Communications (DSOC)
    Led by JPL
    Year: 2023
    Objective: To test laser communications from deep space. An upcoming NASA Discovery mission called Psyche will fly to a metallic asteroid starting in 2023. Psyche is planned to host a laser device called DSOC, which would beam data down to a telescope at Palomar Mountain Observatory in California.
    ___________________________________________________________________

    Science at the speed of light

    Both radio and lasers travel at the speed of light, but lasers travel in a higher-frequency bandwidth. That allows them to carry more information than radio waves, which is crucial when you’re collecting massive amounts of data and have narrow windows of time to send it back to Earth.

    A good example is NASA’s Mars Reconnaissance Orbiter, which sends science data at a blazing maximum of 6 Mbps. Biswas estimated that if the orbiter used laser comms technology with a mass and power usage comparable to its current radio system, it could probably increase the maximum data rate to 250 Mbps.

    That might still sound stunningly slow to Internet users. But on Earth, data is sent over far shorter distances and through infrastructure that doesn’t exist yet in space, so it travels even faster.

    Increasing data rates would allow scientists to spend more of their time on analysis than on spacecraft operations.

    “It’s perfect when things are happening fast and you want a dense data set,” said Dave Pieri, a JPL research scientist and volcanologist. Pieri has led past research on how laser comms could be used to study volcanic eruptions and wildfires in near real-time. “If you have a volcano exploding in front of you, you want to assess its activity level and propensity to keep erupting. The sooner you get and process that data, the better.”

    That same technology could apply to erupting cryovolcanoes on icy moons around other planets. Pieri noted that compared to radio transmission of events like these, “laser comms would up the ante by an order of magnitude.”

    Clouding the future of lasers

    That’s not to say the technology is perfect for every scenario. Lasers are subject to more interference from clouds and other atmospheric conditions than radio waves; pointing and timing are also challenges.

    Lasers also require ground infrastructure that doesn’t yet exist. NASA’s Deep Space Network, a system of antenna arrays located across the globe, is based entirely on radio technology. Ground stations would have to be developed that could receive lasers in locations where skies are reliably clear.

    Radio technology won’t be going away. It works in rain or shine, and will continue to be effective for low-data uses like providing commands to spacecraft.

    Next steps

    Two upcoming NASA missions will help engineers understand the technical challenges involved in conducting laser communications in space. What they’ll learn will advance lasers toward becoming a common form of space communication in the future.

    The Laser Communications Relay Demonstration (LCRD), led by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is due to launch in 2019. LCRD will demonstrate the relay of data using laser and radio frequency technology. It will beam laser signals almost 25,000 miles (40,000 kilometers) from a ground station in California to a satellite in geostationary orbit, then relay that signal to another ground station. JPL is developing one of the ground stations at Table Mountain in southern California. Testing laser communications in geostationary orbit, as LCRD will do, has practical applications for data transfer on Earth.

    Deep Space Optical Communications (DSOC), led by JPL, is scheduled to launch in 2023 as part of an upcoming NASA Discovery mission. That mission, Psyche, will fly to a metallic asteroid, testing laser comms from a much greater distance than LCRD.

    The Psyche mission has been planned to carry the DSOC laser device onboard the spacecraft. Effectively, the DSOC mission will try to hit a bullseye using a deep space laser — and because of the planet’s rotation, it will hit a moving target, as well.

    http://go.nasa.gov/2gBzbyx

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

    Caltech Logo

    NASA image

     
  • richardmitnick 6:03 pm on February 14, 2017 Permalink | Reply
    Tags: , NASA Goddard, Quantum dot spectrometer   

    From Goddard: “NASA and MIT Collaborate to Develop Space-Based Quantum-Dot Spectrometer” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Feb. 14, 2017
    Lori Keesey
    lori.keesey@nasa.gov
    NASA’s Goddard Space Flight Center

    1
    Principal Investigator Mahmooda Sultana has teamed with the Massachusetts Institute of Technology to develop a quantum dot spectrometer for use in space. In this photo, she is characterizing the optical properties of the quantum dot pixels.
    Credits: NASA/W. Hrybyk

    A NASA technologist has teamed with the inventor of a new nanotechnology that could transform the way space scientists build spectrometers, the all-important device used by virtually all scientific disciplines to measure the properties of light emanating from astronomical objects, including Earth itself.

    Mahmooda Sultana, a research engineer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, now is collaborating with Moungi Bawendi, a chemistry professor at the Cambridge-based Massachusetts Institute of Technology, or MIT, to develop a prototype imaging spectrometer based on the emerging quantum-dot technology that Bawendi’s group pioneered.

    NASA’s Center Innovation Fund, which supports potentially trailblazing, high-risk technologies, is funding the effort.

    Introducing Quantum Dots

    2
    This illustration shows how a device prints the quantum dot filters that absorb different wavelengths of light depending on their size and composition. The emerging technology could give scientists a more flexible, cost-effective approach for developing spectrometers, a commonly used instrument. Credits: O’Reilly Science Art

    Quantum dots are a type of semiconductor nanocrystal discovered in the early 1980s. Invisible to the naked eye, the dots have proven in testing to absorb different wavelengths of light depending on their size, shape, and chemical composition. The technology is promising to applications that rely on the analysis of light, including smartphone cameras, medical devices, and environmental-testing equipment.

    “This is as novel as it gets,” Sultana said, referring to the technology that she believes could miniaturize and potentially revolutionize space-based spectrometers, particularly those used on uninhabited aerial vehicles and small satellites. “It really could simplify instrument integration.”

    Absorption spectrometers, as their name implies, measure the absorption of light as a function of frequency or wavelength due to its interaction with a sample, such as atmospheric gases.

    After passing through or interacting with the sample, the light reaches the spectrometer. Traditional spectrometers use gratings, prisms, or interference filters to split the light into its component wavelengths, which their detector pixels then detect to produce spectra. The more intense the absorption in the spectra, the greater the presence of a specific chemical.

    While space-based spectrometers are getting smaller due to miniaturization, they still are relatively large, Sultana said. “Higher-spectral resolution requires long optical paths for instruments that use gratings and prisms. This often results in large instruments. Whereas here, with quantum dots that act like filters that absorb different wavelengths depending on their size and shape, we can make an ultra-compact instrument. In other words, you could eliminate optical parts, like gratings, prisms, and interference filters.”

    Just as important, the technology allows the instrument developer to generate nearly an unlimited number of different dots. As their size decreases, the wavelength of the light that the quantum dots will absorb decreases. “This makes it possible to produce a continuously tunable, yet distinct, set of absorptive filters where each pixel is made of a quantum dot of a specific size, shape, or composition. We would have precise control over what each dot absorbs. We could literally customize the instrument to observe many different bands with high-spectral resolution.”

    Prototype Instrument Under Development

    With her NASA technology-development support, Sultana is working to develop, qualify through thermal vacuum and vibration tests, and demonstrate a 20-by-20 quantum-dot array sensitive to visible wavelengths needed to image the sun and the aurora. However, the technology easily can be expanded to cover a broader range of wavelengths, from ultraviolet to mid-infrared, which may find many potential space applications in Earth science, heliophysics, and planetary science, she said.

    Under the collaboration, Sultana is developing an instrument concept particularly for a CubeSat application and MIT doctoral student Jason Yoo is investigating techniques for synthesizing different precursor chemicals to create the dots and then printing them onto a suitable substrate. “Ultimately, we would want to print the dots directly onto the detector pixels,” she said.

    “This is a very innovative technology,” Sultana added, conceding that it is very early in its development. “But we’re trying to raise its technology-readiness level very quickly. Several space-science opportunities that could benefit are in the pipeline.”

    For more Goddard technology news, go to: http://gsfctechnology.gsfc.nasa.gov/newsletter/Current.pdf

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard campus
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 5:04 pm on February 8, 2017 Permalink | Reply
    Tags: Ion escape, NASA Goddard, Oxygen escape, , Proxima b is subjected to torrents of X-ray and extreme ultraviolet radiation from superflares occurring roughly every two hours., , Stellar eruptions such as flares and coronal mass ejections – collectively called space weather, We have pessimistic results for planets around young red dwarfs in this study   

    From Goddard: “NASA Finds Planets of Red Dwarf Stars May Face Oxygen Loss in Habitable Zones” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Feb. 8, 2017
    Lina Tran
    kathalina.k.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    3
    Credit: NASA

    The search for life beyond Earth starts in habitable zones, the regions around stars where conditions could potentially allow liquid water – which is essential for life as we know it – to pool on a planet’s surface. New NASA research suggests some of these zones might not actually be able to support life due to frequent stellar eruptions – which spew huge amounts of stellar material and radiation out into space – from young red dwarf stars.

    Now, an interdisciplinary team of NASA scientists wants to expand how habitable zones are defined, taking into account the impact of stellar activity, which can threaten an exoplanet’s atmosphere with oxygen loss. This research was published in The Astrophysical Journal Letters on Feb. 6, 2017.

    “If we want to find an exoplanet that can develop and sustain life, we must figure out which stars make the best parents,” said Vladimir Airapetian, lead author of the paper and a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We’re coming closer to understanding what kind of parent stars we need.”

    To determine a star’s habitable zone, scientists have traditionally considered how much heat and light the star emits. Stars more massive than our sun produce more heat and light, so the habitable zone must be farther out. Smaller, cooler stars yield close-in habitable zones.

    But along with heat and visible light, stars emit X-ray and ultraviolet radiation, and produce stellar eruptions such as flares and coronal mass ejections – collectively called space weather. One possible effect of this radiation is atmospheric erosion, in which high-energy particles drag atmospheric molecules – such as hydrogen and oxygen, the two ingredients for water – out into space. Airapetian and his team’s new model for habitable zones now takes this effect into account.


    In this artist’s concept, X-ray and extreme ultraviolet light from a young red dwarf star cause ions to escape from an exoplanet’s atmosphere. Scientists have developed a model that estimates the oxygen ion escape rate on planets around red dwarfs, which plays an important role in determining an exoplanet’s habitability.
    Credits: NASA Goddard/Conceptual Image Lab, Michael Lentz, animator/Genna Duberstein, producer

    The search for habitable planets often hones in on red dwarfs, as these are the coolest, smallest and most numerous stars in the universe – and therefore relatively amenable to small planet detection.

    “On the downside, red dwarfs are also prone to more frequent and powerful stellar eruptions than the sun,” said William Danchi, a Goddard astronomer and co-author of the paper. “To assess the habitability of planets around these stars, we need to understand how these various effects balance out.”

    Another important habitability factor is a star’s age, say the scientists, based on observations they’ve gathered from NASA’s Kepler mission. Every day, young stars produce superflares, powerful flares and eruptions at least 10 times more powerful than those observed on the sun. On their older, matured counterparts resembling our middle-aged sun today, such superflares are only observed once every 100 years.

    “When we look at young red dwarfs in our galaxy, we see they’re much less luminous than our sun today,” Airapetian said. “By the classical definition, the habitable zone around red dwarfs must be 10 to 20 times closer-in than Earth is to the sun. Now we know these red dwarf stars generate a lot of X-ray and extreme ultraviolet emissions at the habitable zones of exoplanets through frequent flares and stellar storms.”

    Superflares cause atmospheric erosion when high-energy X-ray and extreme ultraviolet emissions first break molecules into atoms and then ionize atmospheric gases. During ionization, radiation strikes the atoms and knocks off electrons. Electrons are much lighter than the newly formed ions, so they escape gravity’s pull far more readily and race out into space.

    Opposites attract, so as more and more negatively charged electrons are generated, they create a powerful charge separation that lures positively charged ions out of the atmosphere in a process called ion escape.

    “We know oxygen ion escape happens on Earth at a smaller scale since the sun exhibits only a fraction of the activity of younger stars,” said Alex Glocer, a Goddard astrophysicist and co-author of the paper. “To see how this effect scales when you get more high-energy input like you’d see from young stars, we developed a model.”

    The model estimates the oxygen escape on planets around red dwarfs, assuming they don’t compensate with volcanic activity or comet bombardment. Various earlier atmospheric erosion models indicated hydrogen is most vulnerable to ion escape. As the lightest element, hydrogen easily escapes into space, presumably leaving behind an atmosphere rich with heavier elements such as oxygen and nitrogen.

    But when the scientists accounted for superflares, their new model indicates the violent storms of young red dwarfs generate enough high-energy radiation to enable the escape of even oxygen and nitrogen – building blocks for life’s essential molecules.

    “The more X-ray and extreme ultraviolet energy there is, the more electrons are generated and the stronger the ion escape effect becomes,” Glocer said. “This effect is very sensitive to the amount of energy the star emits, which means it must play a strong role in determining what is and is not a habitable planet.”

    Considering oxygen escape alone, the model estimates a young red dwarf could render a close-in exoplanet uninhabitable within a few tens to a hundred million years. The loss of both atmospheric hydrogen and oxygen would reduce and eliminate the planet’s water supply before life would have a chance to develop.

    “The results of this work could have profound implications for the atmospheric chemistry of these worlds,” said Shawn Domagal-Goldman, a Goddard space scientist not involved with the study. “The team’s conclusions will impact our ongoing studies of missions that would search for signs of life in the chemical composition of those atmospheres.”

    Modeling the oxygen loss rate is the first step in the team’s efforts to expand the classical definition of habitability into what they call space weather-affected habitable zones. When exoplanets orbit a mature star with a mild space weather environment, the classical definition is sufficient. When the host star exhibits X-ray and extreme ultraviolet levels greater than seven to 10 times the average emissions from our sun, then the new definition applies. The team’s future work will include modeling nitrogen escape, which may be comparable to oxygen escape since nitrogen is just slightly lighter than oxygen.

    The new habitability model has implications for the recently discovered planet orbiting the red dwarf Proxima Centauri, our nearest stellar neighbor. Airapetian and his team applied their model to the roughly Earth-sized planet, dubbed Proxima b, which orbits Proxima Centauri 20 times closer than Earth is to the sun.

    Considering the host star’s age and the planet’s proximity to its host star, the scientists expect that Proxima b is subjected to torrents of X-ray and extreme ultraviolet radiation from superflares occurring roughly every two hours. They estimate oxygen would escape Proxima b’s atmosphere in 10 million years. Additionally, intense magnetic activity and stellar wind – the continuous flow of charged particles from a star – exacerbate already harsh space weather conditions. The scientists concluded that it’s quite unlikely Proxima b is habitable.

    “We have pessimistic results for planets around young red dwarfs in this study, but we also have a better understanding of which stars have good prospects for habitability,” Airapetian said. “As we learn more about what we need from a host star, it seems more and more that our sun is just one of those perfect parent stars, to have supported life on Earth.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard campus
    NASA/Goddard Campus
    NASA image

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: