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  • richardmitnick 5:39 am on July 19, 2014 Permalink | Reply
    Tags: , , , CFH Telescope,   

    From CFH: “Fingerprinting the formation of giant planets” 

    CFHT icon
    Canada France Hawaii telescope

    July 17th 2014
    Media contact
    Dr. Daniel Devost
    Canada-France-Hawaii Telescope
    (808) 885-3163
    devost@cfht.hawaii.edu

    Science contacts
    Marcelo Tucci Maia
    Universidade do São Paulo
    marcelotuccimaia@usp.br

    Prof. Jorge Meléndez
    Universidade de São Paulo
    jorge.melendez@iag.usp.br

    Dr. Ivan Ramírez
    University of Texas
    ivan@astro.as.utexas.edu

    A team of Brazilian and American astronomers used CFHT observations of the system 16 Cygni to discover evidence of how giant planets like Jupiter form.

    Canada-France-Hawaii Telescope
    CFH

    16 cygni

    One of the main models to form giant planets is called “core accretion”. In this scenario, a rocky core forms first by aggregation of solid particles until it reaches a few Earth masses when it becomes massive enough to accrete a gaseous envelope. For the first time, astronomers have detected evidence of this rocky core, the first step in the formation of a giant planet like our own Jupiter.

    chart
    Difference in chemical composition between the stars 16 Cyg A and 16 Cyg B, versus the condensation temperature of the elements in the proto-planetary nebula. If the stars had identical chemical compositions then the difference (A-B) would be zero. The star 16 Cyg A is richer in all elements relative to star 16 Cyg B. In other words, star 16 Cyg B, the host star of a giant planet, is deficient in all chemical elements, especially in the refractory elements (those with high condensation temperatures and that form dust grains more easily), suggesting evidence of a rocky core in the giant planet 16 Cyg Bb. Credits: M. Tucci Maia, J. Meléndez, I. Ramírez.

    The astronomers used the Canada-France-Hawaii Telescope (CFHT) to analyze the starlight of the binary stars 16 Cygni A and 16 Cygni B. The system is a perfect laboratory to study the formation of giant planets because the stars were born together and are therefore very similar, and both resemble the Sun. However, observations during the last decades show that only one of the two stars, 16 Cygni B, hosts a giant planet which is about 2.4 times as massive as Jupiter. By decomposing the light from the two stars into their basic components and looking at the difference between the two stars, the astronomers were able to detect signatures left from the planet formation process on 16 Cygni B.

    The fingerprints detected by the astronomers are twofold. First, they found that the star 16 Cygni A is enhanced in all chemical elements relative to 16 Cygni B. This means that 16 Cygni B, the star that hosts a giant planet, is metal deficient. As both stars were born from the same natal cloud, they should have exactly the same chemical composition. However, planets and stars form at about the same time, hence the metals that are missing in 16 Cygni B (relative to 16 Cygni A) were probably removed from its protoplanetary disk to form its giant planet, so that the remaining material that was falling into 16 Cygni B in the final phases of its formation was deficient in those metals.

    The second fingerprint is that on top of an overall deficiency of all analyzed elements in 16 Cygni B, this star has a systematic deficiency in the refractory elements such as iron, aluminum, nickel, magnesium, scandium, and silicon. This is a remarkable discovery because the rocky core of a giant planet is expected to be rich in refractory elements. The formation of the rocky core seems to rob refractory material from the proto-planetary disk, so that the star 16 Cygni B ended up with a lower amount of refractories. This deficiency in the refractory elements can be explained by the formation of a rocky core with a mass of about 1.5 – 6 Earth masses, which is similar to the estimate of Jupiter’s core.

    “Our results show that the formation of giant planets, as well as terrestrial planets like our own Earth, leaves subtle signatures in stellar atmospheres”, says Marcelo Tucci Maia (Universidade de São Paulo), the lead author of the paper. “It is fascinating that our differential technique can measure these subtle differences in chemical abundances; we achieve a precision that was unthinkable until now”, adds team member Jorge Meléndez (Universidade de São Paulo). Ivan Ramírez (University of Texas) concludes: “16 Cyg is a remarkable system, but certainly not unique. It is special because it is nearby; however, there are many other binary stars with twin components on which this experiment could be performed. This could help us find planet-host stars in binaries in a much more straightforward manner compared to all other planet-finding techniques we have available today.”

    The team is composed of the PhD student Marcelo Tucci Maia, Prof. Dr. Jorge Meléndez (Universidade de São Paulo) and Dr. Iván Ramírez (University of Texas at Austin). This research will appear in the paper High precision abundances in the 16 Cyg binary system: a signature of the rocky core in the giant planet, by M. Tucci Maia, J. Meléndez and I. Ramírez, in the Astrophysical Journal Letters.

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.


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  • richardmitnick 5:09 am on March 30, 2014 Permalink | Reply
    Tags: , , , CFH Telescope, , ,   

    From NASA: “Stephan’s Quintet Plus One” A Real Beauty 

    NASA

    The first identified compact galaxy group, Stephan’s Quintet is featured in this remarkable image constructed with data drawn from Hubble Legacy Archive and the Subaru Telescope on the summit of Mauna Kea. The galaxies of the quintet are gathered near the center of the field, but really only four of the five are locked in a cosmic dance of repeated close encounters taking place some 300 million light-years away. The odd man out is easy to spot, though. The interacting galaxies, NGC 7319, 7318A and 7318B, and 7317 have a more dominant yellowish cast. They also tend to have distorted loops and tails, grown under the influence of disruptive gravitational [galactic] tides. The mostly bluish galaxy, NGC 7320, is in the foreground about 40 million light-years distant, and isn’t part of the interacting group. Still, captured in this field above and to the left of Stephan’s Quintet is another galaxy, NGC 7320C, that is also 300 million light-years distant. Of course, including it would bring the four interacting galaxies back up to quintet status. Stephan’s Quintet lies within the boundaries of the high flying constellation Pegasus. At the estimated distance of the quintet’s interacting galaxies, this field of view spans over 500,000 light-years.

    sq
    Image Credits Optical: Subaru October 26, 2011
    Image Credits: X-ray: NASA/CXC/CfA/E. O’Sullivan Optical: Canada-France-Hawaii-Telescope/Coelum
    15 February 2006

    From Spitzer
    sq2
    Date 2006-03-02
    Credit NASA/JPL-Caltech/Max-Planck Institute/P. Appleton (Spitzer Science Center/Caltech)
    Observers
    Spitzer data: P. Appleton (SSC/Caltech) K. Xu (SSC/Caltech) W. Reach (SSC/Caltech) M. Dopita (Australian National University) Y. Gao (Purple Mountain Observatory, China) N. Lu (SSC/Caltech) C. Popescu (Max Planck Institut fuer Kernphysik, Heidelberg, Germany) J. Sulentic (University of Alabama) R. Tuffs (Max Planck Institut fuer Kernphysik, Heidelberg, Germany) M. Yun (University of Massachusetts)

    region
    The galaxies in the vicinity of Stephan’s Quintet. The rectangle indicates the area covered by the 1998–99 Hubble Space Telescope image.

    NASA Spitzer Telescope
    NASA/Spitzer

    NAOJ Subaru Telescope
    NAOJ/Subaru

    NASA Chandra Telescope
    NASA/Chandra

    Canada-France-Hawaii Telescope
    Canada-France-Hawaii Telescope

    See the full article here.

    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

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

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

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


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