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Re: ScienceDaily: New Rocky Planet Found In Constellation Leo

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  • mahtezcatpoc
    ... BLGD. Mark A. Holmes ... New Rocky Planet Found In Constellation Leo ScienceDaily (Apr. 9, 2008) — Spanish and UCL (University College London) scientists
    Message 1 of 2 , Apr 9, 2008
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      --- In thefixedstars@yahoogroups.com, mahtezcatpoc@... wrote:
      >
      > Mark Andrew Holmes (mahtezcatpoc@...) has sent you a link to the
      following page on ScienceDaily:
      >
      > New Rocky Planet Found In Constellation Leo
      > http://www.sciencedaily.com/releases/2008/04/080409113958.htm

      BLGD.

      Mark A. Holmes

      ...

      New Rocky Planet Found In Constellation Leo


      ScienceDaily (Apr. 9, 2008) — Spanish and UCL (University College
      London) scientists have discovered a possible terrestrial-type planet
      orbiting a star in the constellation of Leo. The new planet, which
      lies at a distance of 30 light years from the Earth, has a mass five
      times that of our planet but is the smallest found to date. One full
      day on the new planet would be equivalent to three weeks on Earth.


      The team of astronomers from the Spanish Research Council (CSIC)
      working with Dr Jean-Philippe Beaulieu, a visiting astrophysicist at
      UCL, made the discovery from model predictions of a new exoplanet
      (meaning planet outside our solar system) orbiting a star in the
      constellation of Leo. Simulations show that the exoplanet, dubbed GJ
      436c, orbits its host star (GJ 436) in only 5.2 Earth days, and is
      thought to complete a revolution in 4.2 Earth days, compared to the
      Earth's revolution of 24 hours and full orbit of 365 days. On Earth,
      a full day (sunset to sunset) coincides quite closely with the
      rotation period. On the new planet these two periods do not coincide,
      since the orbital translation period and the rotation period are very
      similar. For this reason, a full day on the new planet would take
      four planetary years, or roughly 22 Earth days.

      The study, published recently in Astrophysical Journal, predicted the
      presence of a small exoplanet perturbing an inner planet (already
      known), producing changes on its orbit. A re-analysis of archival
      radial velocities also permitted the identification of a signal that
      perfectly matches the simulations and corresponds to a planet in
      resonance with the inner one, meaning that for every two orbits of
      the known planet the new planet completes one.

      Ignasi Ribas, lead author of the study from CSIC, says: "After final
      confirmation, the new exoplanet will be the smallest found to date.
      It is the first one to be identified from the perturbations exerted
      on another planet of the system. Because of this, the study opens a
      new path that should lead to the discovery of even smaller planets in
      the near future, with the goal of eventually finding worlds more and
      more similar to the Earth."

      Dr Jean-Philippe Beaulieu, visiting astrophysicist at UCL Physics and
      Astronomy, says: "This is the fourth super-Earth planet discovered.
      This planet is the hot twin of the frozen super-Earth (OGLE-2005-BLG-
      390lb) we discovered by microlensing two years ago. Other previously
      discovered planets of this class are the two hot super-Earths Gl 581b
      and Gl 876d detected by their Doppler wobble."

      Dr Giovanna Tinetti, UCL Physics and Astronomy who recently
      calculated the putative properties of this planet,
      says: "Calculations indicate that the temperature of the planet could
      be within 400-700 Kelvin [127-427 Celsius], but it could locally be
      as low as 350 K [77 C] at the poles, depending on the type of
      atmosphere."

      Most of the 280 or so planets discovered to date are gas giants
      similar to Jupiter, although some with masses below 10 times that of
      the Earth have already been found. Planets with masses of between one
      and 10 times the Earth are often dubbed super-Earths. In this case,
      current models predict that the new planet is a rocky type and has a
      radius some 50 per cent larger than the Earth.

      Journal reference: `A 5 M super-Earth orbiting GJ 436? The power of
      near-grazing transits' is published the week of April 6 in
      Astrophysical Journal.
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