Science and techno world topic: Space
A team of astronomers using NASA’s Hubble Space Telescope
is reporting the discovery of another moon orbiting the icy dwarf planet Pluto.
Photo: This image, taken
by NASA's Hubble Space Telescope, shows five moons orbiting the distant, icy
dwarf planet Pluto. The green circle marks the newly discovered moon,
designated P5, as photographed by Hubble's Wide Field Camera 3 on July 7. The
observations will help scientists in their planning for the July 2015 flyby of
Pluto by NASA's New Horizons spacecraft. P4 was uncovered in Hubble imagery in
2011. (Credit: NASA; ESA; M. Showalter, SETI Institute)
The moon is estimated to be irregular in shape and 6 to
15 miles across. It is in a 58,000-mile-diameter circular orbit around Pluto
that is assumed to be co-planar with the other satellites in the system.
“The moons form a series of neatly nested orbits, a bit
like Russian dolls,” said team lead Mark Showalter of the SETI Institute in
Mountain View, Calif.
The discovery increases the number of known moons
orbiting Pluto to five.
The Pluto team is intrigued that such a small planet can
have such a complex collection of satellites. The new discovery provides
additional clues for unraveling how the Pluto system formed and evolved. The
favored theory is that all the moons are relics of a collision between Pluto
and another large Kuiper belt object billions of years ago.
The new detection will help scientists navigate NASA’s
New Horizons spacecraft through the Pluto system in 2015, when it makes an
historic and long-awaited high-speed flyby of the distant world.
The team is using Hubble’s powerful vision to scour the
Pluto system to uncover potential hazards to the New Horizons spacecraft.
Moving past the dwarf planet at a speed of 30,000 miles per hour, New Horizons
could be destroyed in a collision with even a BB-shot-size piece of orbital
debris.
“The discovery of so many small moons indirectly tells us
that there must be lots of small particles lurking unseen in the Pluto system,”
said Harold Weaver of the Johns Hopkins University Applied Physics Laboratory
in Laurel, Md.
“The inventory of the Pluto system we're taking now with
Hubble will help the New Horizons team design a safer trajectory for the
spacecraft,” added Alan Stern of the Southwest Research Institute in Boulder,
Colo., the mission’s principal investigator.
Pluto’s largest moon, Charon, was discovered in 1978 in
observations made at the United States Naval Observatory in Washington, D.C.
Hubble observations in 2006 uncovered two additional small moons, Nix and
Hydra. In 2011 another moon, P4, was found in Hubble data.
Provisionally designated S/2012 (134340) 1, the latest
moon was detected in nine separate sets of images taken by Hubble’s Wide Field
Camera 3 on June 26, 27, 29, and July 7 and 9.
In the years following the New Horizons Pluto flyby,
astronomers plan to use the infrared vision of Hubble’s planned successor,
NASA’s James Webb Space Telescope, for follow-up observations. The Webb
telescope will be able to measure the surface chemistry of Pluto, its moons,
and many other bodies that lie in the distant Kuiper Belt along with Pluto.
The Pluto Team members are M. Showalter (SETI Institute),
H.A. Weaver (Applied Physics Laboratory, Johns Hopkins University), and S.A.
Stern, A.J. Steffl, and M.W. Buie (Southwest Research Institute).
The Hubble Space Telescope is a project of international
cooperation between NASA and the European Space Agency. NASA's Goddard Space
Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope
Science Institute (STScI) in Baltimore conducts Hubble science operations.
STScI is operated for NASA by the Association of Universities for Research in
Astronomy, Inc., in Washington, D.C.
Source: NASA
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