SETI public: Fw: Hawaiian Telescope Team Makes Debut Discovery

Date: Tue Jul 01 2003 - 17:06:59 PDT

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    ----- Original Message -----
    From: NASA Jet Propulsion Laboratory
    Sent: Tuesday, July 01, 2003 6:39 PM
    Subject: Hawaiian Telescope Team Makes Debut Discovery

    Jane Platt (818) 354-0880
    Jet Propulsion Laboratory, Pasadena, Calif.

    Donald Savage (202) 358-1727
    Headquarters, Washington. D.C.

    Laura Kraft (808) 885-7887
    W.M. Keck Observatory, Kamuela, Hawaii July 1, 2003

    News Release: 2003-093

    Hawaiian Telescope Team Makes Debut Discovery

    Astronomers have observed a young star ringed by a swirling disc that
    may spin off planets, marking the first published science observation
    using two linked 10-meter (33-
    foot) telescopes in Hawaii.

    The linked telescopes at the W.M. Keck Observatory on Mauna Kea, known
    as the Keck Interferometer, comprise the world's largest optical
    telescope system. The observation was made of DG Tau, a young star
    that has not yet begun to burn hydrogen in its core. Such stars are
    called T-Tauri objects. Observations of DG Tau were made on October
    23, 2002, and February 13, 2003, and the findings will appear in an
    upcoming issue of the Astrophysical Journal Letters.

    "We're trying to measure the size of the hot material in the dust disc
    around DG Tau, where planets may form," said Dr. Rachel Akeson, leader
    of the study team and an astronomer at the Michelson Science Center at
    the California Institute of Technology in Pasadena. "Studies like this
    teach us more about how stars form, either alone or in pairs, and how
    planets eventually form in discs around stars."

    The Keck Interferometer observations revealed a gap of nearly 29
    million kilometers (18 million miles) between DG Tau and its orbiting
    dust disc. Akeson notes that of the extra-solar planets -- planets
    orbiting other stars -- discovered so far, roughly one in four lies
    within 16 million kilometers (10 million miles) of the parent star.
    Since planets are believed to form within a dust disc, either DG Tau's
    disc has a larger-than-usual gap, or the close-in planets form farther
    from the star and migrate inward.

    Since 1995, astronomers have detected more than 100 extra-solar
    planets, many considered too large and close to their hot, parent
    stars to sustain life. By measuring the amount of dust around other
    stars, where planets may form, the Keck Interferometer will pave the
    way for NASA's Terrestrial Planet Finder mission. Terrestrial Planet
    Finder will look for smaller, Earth-like planets that may harbor life.
    The Keck Interferometer and Terrestrial Planet Finder are part of
    NASA's Origins Program, which seeks to answer the questions: Where did
    we come from? Are we alone?

    "T-Tauri objects had been observed with other instruments, but only
    the brightest ones were detectable until now," Akeson said. "With the
    larger telescopes and greater
    sensitivity of the Keck Interferometer, we can look at fainter T-Tauri
    objects, like this one."

    The Keck Interferometer gathers light waves with two telescopes and
    then combines the waves so they interact, or "interfere" with each
    other. It's like throwing a rock into a lake and watching the ripples,
    or waves, and then throwing in a second rock. The second set of waves
    either bumps against the first set and changes its pattern, or both
    sets join together to form larger, more powerful waves. With
    interferometry, the idea is to combine light waves from multiple
    telescopes to simulate a much larger, more powerful telescope.

    In its ability to resolve fine details, the Keck Interferometer is
    equivalent to an 85-meter (279-foot) telescope. "The system transports
    the light gathered by the two telescopes to an optical laboratory
    located in the central building," said Dr. Mark Colavita of NASA's Jet
    Propulsion Laboratory, Pasadena, interferometer system architect and
    lead author of the paper. "In the lab, a beam combiner and infrared
    camera combine and process the collected light to make the science

    To make these measurements, the interferometer's optical system
    adjusts the light paths to a fraction of a wavelength of light, and
    adaptive optics on the telescopes remove the
    distortion caused by Earth's atmosphere.

    "This research represents the first scientific application of an
    interferometer with telescopes that use adaptive optics," said Dr.
    Peter Wizinowich, interferometer team lead for the W.M. Keck
    Observatory and co-author of the paper.

    The development of the Keck Interferometer is managed by JPL for
    NASA's Office of Space Science, Washington. JPL is a division of the
    California Institute of Technology in
    Pasadena. The W.M. Keck Observatory is funded by Caltech, the
    University of California and NASA, and is managed by the California
    Association for Research in Astronomy, Kamuela, Hawaii.

    Additional information and images are available on the Internet at and .


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