Dec 10 2015
From The Space Library
Release M15-171 NASA Highlights Global Air Quality, Moon, El Nino at American Geophysical Union
NASA researchers will present new findings on a wide range of Earth and space science topics at the annual meeting of the American Geophysical Union Dec. 14-18 in San Francisco. NASA-related briefings will be carried live on the agency’s website.
Media registration is open for the event, which will be held at the Moscone Convention Center at 747 Howard St.
NASA briefing topics include: first Earth science results from the agency’s camera on the Deep Space Climate Observatory (DSCOVR) spacecraft; the latest discoveries made by the Mars Curiosity rover; impacts around the world from the current El Nino; and new results from NASA’s Lunar Atmosphere and Dust Environment Explorer mission.
NASA scientists, and their colleagues who use NASA research capabilities, also will present noteworthy findings during scientific sessions that are open to registered media.
What Spawned the Jellyfish Nebula?
The Jellyfish Nebula, also known by its official name IC 443, is the remnant of a supernova lying 5,000 light years from Earth. New Chandra observations show that the explosion that created the Jellyfish Nebula may have also formed a peculiar object located on the southern edge of the remnant, called CXOU J061705.3+222127, or J0617 for short. The object is likely a rapidly spinning neutron star, or pulsar.
When a massive star runs out of thermonuclear fuel, it implodes, forming a dense stellar core called a neutron star. The outer layers of the star collapse toward the neutron star then bounce outward in a supernova explosion. A spinning neutron star that produces a beam of radiation is called a pulsar. The radiation sweeps by like a beacon of light from a lighthouse and can be detected as pulses of radio waves and other types of radiation.
This new composite image includes a wide-field view from an astrophotographer that shows the spectacular filamentary structure of IC 443. Within the inset box, another optical image from the Digitized Sky Survey (red, green, orange, and cyan) has been combined with X-ray data from Chandra (blue). The inset shows a close-up view of the region around J0617.
The Chandra image reveals a small, circular structure (or ring) surrounding the pulsar and a jet-like feature pointing roughly in an up-down direction that passes through the pulsar. It is unclear if the long, pink wisp of optical emission is related to the pulsar, as similar wisps found in IC 443 are unrelated to X-ray features from the pulsar. The ring may show a region where a high speed wind of particles flowing away from the pulsar, is slowing down abruptly. Alternately, the ring may represent a shock wave, similar to a sonic boom, ahead of the pulsar wind. The jet could be particles that are being fired away from the pulsar in a narrow beam at high speed.
The X-ray brightness of J0617 and its X-ray spectrum, or the amount of X-rays at different wavelengths, are consistent with the profiles from known pulsars. The spectrum and shape of the diffuse, or spread out, X-ray emission surrounding J0617 and extending well beyond the ring also match with expectations for a wind flowing from a pulsar.
The comet-like shape of the diffuse X-ray emission suggests motion towards the lower right of the image. As pointed out in previous studies, this orientation is about 50 degrees away from the direction expected if the pulsar was moving away from the center of the supernova remnant in a straight line. This misalignment has cast some doubt on the association of the pulsar with the supernova remnant. However, this misalignment could also be explained by movement towards the left of material in the supernova remnant pushing J0617’s cometary tail aside.
This latest research points to an estimate for the age of the supernova remnant to be tens of thousands of years. This agrees with previous work that pegged IC 443’s age to be about 30,000 years. However, other scientists have inferred much younger ages of about 3,000 years for this supernova remnant, so its true age remains in question.
These findings are available in a paper published in The Astrophysical Journal and is available online. The authors are Douglas Swartz (Marshall Space Flight Center), George Pavlov (Penn State University), Tracy Clarke (Naval Research Laboratory), Gabriela Castelletti (IAEF, Argentina), Vyacheslav Zavlin (MSFC), Niccolo Bucciantini (INAF, Italy), Margarita Karovska (Smithsonian Astrophysical Observatory), Alexander van der Horst (George Washington University), Mihoko Yukita (Goddard Space Flight Center), and Martin Weisskopf (MSFC).
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
NASA Telescopes Detect Jupiter-Like Storm on Small Star
Astronomers have discovered what appears to be a tiny star with a giant, cloudy storm, using data from NASA's Spitzer and Kepler space telescopes. The dark storm is akin to Jupiter's Great Red Spot: a persistent, raging storm larger than Earth.
"The star is the size of Jupiter, and its storm is the size of Jupiter's Great Red Spot," said John Gizis of the University of Delaware, Newark. "We know this newfound storm has lasted at least two years, and probably longer." Gizis is the lead author of a new study appearing in The Astrophysical Journal.
While planets have been known to have cloudy storms, this is the best evidence yet for a star that has one. The star, referred to as W1906+40, belongs to a thermally cool class of objects called L-dwarfs. Some L-dwarfs are considered stars because they fuse atoms and generate light, as our sun does, while others, called brown dwarfs, are known as "failed stars" for their lack of atomic fusion.
The L-dwarf in the study, W1906+40, is thought to be a star based on estimates of its age (the older the L-dwarf, the more likely it is a star). Its temperature is about 3,500 degrees Fahrenheit (2,200 Kelvin). That may sound scorching hot, but as far as stars go, it is relatively cool. Cool enough, in fact, for clouds to form in its atmosphere.
"The L-dwarf's clouds are made of tiny minerals," said Gizis.
Spitzer has observed other cloudy brown dwarfs before, finding evidence for short-lived storms lasting hours and perhaps days.
In the new study, the astronomers were able to study changes in the atmosphere of W1906+40 for two years. The L-dwarf had initially been discovered by NASA's Wide-field Infrared Survey Explorer in 2011. Later, Gizis and his team realized that this object happened to be located in the same area of the sky where NASA's Kepler mission had been staring at stars for years to hunt for planets.
Kepler identifies planets by looking for dips in starlight as planets pass in front of their stars. In this case, astronomers knew observed dips in starlight weren't coming from planets, but they thought they might be looking at a star spot -- which, like our sun's "sunspots," are a result of concentrated magnetic fields. Star spots would also cause dips in starlight as they rotate around the star.
Follow-up observations with Spitzer, which detects infrared light, revealed that the dark patch was not a magnetic star spot but a colossal, cloudy storm with a diameter that could hold three Earths. The storm rotates around the star about every 9 hours. Spitzer's infrared measurements at two infrared wavelengths probed different layers of the atmosphere and, together with the Kepler visible-light data, helped reveal the presence of the storm.
While this storm looks different when viewed at various wavelengths, astronomers say that if we could somehow travel there in a starship, it would look like a dark mark near the polar top of the star.
The researchers plan to look for other stormy stars and brown dwarfs using Spitzer and Kepler in the future.
"We don't know if this kind of star storm is unique or common, and we don't why it persists for so long," said Gizis.
Other authors of the study are: Adam Burgasser--University of California, San Diego; Kelle Cruz, Sara Camnasio and Munazza Alam--Hunter College, New York City, New York; Stanimir Metchev--University of Western Ontario, Canada; Edo Berger and Peter Williams--Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts; Kyle Dettman--University of Delaware, Newark; and Joseph Filippazzo--College of Staten Island, New York.
NASA's Ames Research Center in Moffett Field, California, manages the Kepler and K2 missions for NASA’s Science Mission Directorate. JPL managed Kepler mission development. Ball Aerospace & Technologies Corp. operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.
JPL manages the Spitzer Space Telescope mission for NASA. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech.
