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Commentary On The Press Release “A Drastic Chemical Change Occurring In Birth Of Planetary System: Has The Solar System Also Experienced it?”

February 13, 2014 Leave a comment

An infrared image of the protostar L1527 taken by the Spitzer Space Telescope. Credit: J. Tobin/NASA/JPL-Caltech

An infrared image of the protostar L1527 taken by the Spitzer Space Telescope.
Credit: J. Tobin/NASA/JPL-Caltech

Stars are formed by the contraction of interstellar gas and dust. Around a protostar, gas and dust form a disk in which planets are eventually formed. Then, are the chemical compositions of the interstellar cloud and the disk identical? The new ALMA observations show that the answer is ‘no.’ This finding has a large impact on understandings of the formation process of planets and protoplanetary disks.

The international research team, led by Dr. Nami Sakai, an assistant professor at the Department of Physics, The University of Tokyo, observed a baby star L1527 in the constellation Taurus with ALMA. The team observed radio emission from cyclic-C3H2 [note 1] and sulfur monoxide (SO) molecules to analyze the motion and temperature of the gas around the baby star.

L1527 is a well-known protostar (baby star) and many astronomers have pointed telescopes at it. For example, NASA’s Spitzer Space Telescope took infrared images of the star. The stellar light escapes through a cavity excavated by a powerful bipolar gas flow from the star and illuminates the surrounding gas, which makes a butterfly-shaped nebula extending in the east-west direction (Figure 1). Past radio observations revealed that gas is circling around the star to form a disk and we see the disk edge-on.

Radio observations by ALMA have the advantage of being able to see the gas directly, which is invisible in infrared light. Various molecules in the gas emit characteristic radiation as radio waves under characteristic conditions (temperature, density, chemical compositions). Therefore astronomers can investigate the nature of the gas by observing various molecules.

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IBEX Research Shows Influence Of Galactic Magnetic Field Extends Well Beyond Our Solar System

February 13, 2014 Leave a comment

In a report published today, new research suggests the enigmatic “ribbon” of energetic particles discovered at the edge of our solar system by NASA’s Interstellar Boundary Explorer (IBEX) may be only a small sign of the vast influence of the galactic magnetic field.

IBEX researchers have sought answers about the ribbon since its discovery in 2009. Comprising primarily space physicists, the IBEX team realized that the galactic magnetic field wrapped around our heliosphere — the giant “bubble” that envelops and protects our solar system — appears to determine the orientation of the ribbon and the placement of energetic particles measured in it.

An unlikely teaming of IBEX researchers with ultra-high-energy cosmic ray physicists, however, has produced complementary insights that dovetail with IBEX’s studies to produce a more complete picture of the interactions at the solar system boundary and how they reach much farther out into the space between the stars.

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NASA Spacecraft Get A 360-Degree View Of Saturn’s Auroras

February 13, 2014 Leave a comment

Image credit: NASA/JPL-Caltech/University of Colorado/Central Arizona College and NASA/ESA/University of Leicester and NASA/JPL-Caltech/University of Arizona/Lancaster University

Image credit: NASA/JPL-Caltech/University of Colorado/Central Arizona College and NASA/ESA/University of Leicester and NASA/JPL-Caltech/University of Arizona/Lancaster University

NASA trained several pairs of eyes on Saturn as the planet put on a dancing light show at its poles. While NASA’s Hubble Space Telescope, orbiting around Earth, was able to observe the northern auroras in ultraviolet wavelengths, NASA’s Cassini spacecraft, orbiting around Saturn, got complementary close-up views in infrared, visible-light and ultraviolet wavelengths. Cassini could also see northern and southern parts of Saturn that don’t face Earth.

The result is a kind of step-by-step choreography detailing how the auroras move, showing the complexity of these auroras and how scientists can connect an outburst from the sun and its effect on the magnetic environment at Saturn. A new video showing aurora images from Hubble and Cassini is available here.

“Saturn’s auroras can be fickle — you may see fireworks, you may see nothing,” said Jonathan Nichols of the University of Leicester in England, who led the work on the Hubble images. “In 2013, we were treated to a veritable smorgasbord of dancing auroras, from steadily shining rings to super-fast bursts of light shooting across the pole.”

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How Stellar Death Can Lead To Twin Celestial Jets

February 13, 2014 Leave a comment

Credit: NASA/ESA & Valentin Bujarrabal

Credit: NASA/ESA & Valentin Bujarrabal

Astronomers know that while large stars can end their lives as violently cataclysmic supernovae, smaller stars end up as planetary nebulae – colourful, glowing clouds of dust and gas. In recent decades these nebulae, once thought to be mostly spherical, have been observed to often emit powerful, bipolar jets of gas and dust. But how do spherical stars evolve to produce highly aspherical planetary nebulae?

In a theoretical paper published this week in the Monthly Notices of the Royal Astronomical Society, a University of Rochester professor and his undergraduate student conclude that only “strongly interacting” binary stars – or a star and a massive planet – can feasibly give rise to these powerful jets.

When these smaller stars run out of hydrogen to burn they begin to expand and become Asymptotic Giant Branch (AGB) stars. This phase in a star’s life lasts at most 100,000 years. At some point some of these AGB stars, which represent the distended last spherical stage in the lives of low mass stars, become “pre-planetary” nebula, which are aspherical.

“What happens to change these spherical AGB stars into non-spherical nebulae, with two jets shooting out in opposite directions?” asks Eric Blackman, professor of physics and astronomy at Rochester. “We have been trying to come up with a better understanding of what happens at this stage.”

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Largest Solar System Moon Detailed In Geologic Map

February 13, 2014 Leave a comment

Image credit: USGS Astrogeology Science Center/Wheaton/NASA/JPL-Caltech

Image credit: USGS Astrogeology Science Center/Wheaton/NASA/JPL-Caltech

More than 400 years after its discovery by astronomer Galileo Galilei, the largest moon in the solar system – Jupiter’s moon Ganymede – has finally claimed a spot on the map.

More than 400 years after its discovery by astronomer Galileo Galilei, the largest moon in the solar system – Jupiter’s moon Ganymede – has finally claimed a spot on the map.

A group of scientists led by Geoffrey Collins of Wheaton College has produced the first global geologic map of Ganymede, Jupiter’s seventh moon. The map combines the best images obtained during flybys conducted by NASA’s Voyager 1 and 2 spacecraft (1979) and Galileo orbiter (1995 to 2003) and is now published by the U. S. Geological Survey as a global map. It technically illustrates the varied geologic character of Ganymede’s surface and is the first global, geologic map of this icy, outer-planet moon. The geologic map of Ganymede is available for download here.

“This map illustrates the incredible variety of geological features on Ganymede and helps to make order from the apparent chaos of its complex surface,” said Robert Pappalardo of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “This map is helping planetary scientists to decipher the evolution of this icy world and will aid in upcoming spacecraft observations.”

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Four New Galaxy Clusters Take Researchers Further Back In Time

February 13, 2014 Leave a comment

pia17934-640_smFour unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth.

An international team of astronomers, led by Imperial College London, used a new way of combining data from the two European Space Agency satellites, Planck and Herschel, to identify more distant galaxy clusters than has previously been possible. The researchers believe up to 2000 further clusters could be identified using this technique, helping to build a more detailed timeline of how clusters are formed.

Galaxy clusters are the most massive objects in the universe, containing hundreds to thousands of galaxies, bound together by gravity. While astronomers have identified many nearby clusters, they need to go further back in time to understand how these structures are formed. This means finding clusters at greater distances from the Earth.

The light from the most distant of the four new clusters identified by the team has taken over 10 billion years to reach us. This means the researchers are seeing what the cluster looked like when the universe was just three billion years old.

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