After careful consideration and analysis, the Hubble Space Telescope Time
Allocation Committee has recommended using Hubble to search for an object the
Pluto-bound NASA New Horizons mission could visit after its flyby of Pluto in
July 2015.
This is an artist's rendering of the New Horizons
spacecraft encountering a Kuiper Belt object — a city-sized icy relic left over
from the birth of our solar system. The sun, more than 4.1 billion miles (6.7
billion kilometers) away, shines as a bright star embedded in the glow of the
zodiacal dust cloud. Jupiter and Neptune are visible as orange and blue "stars"
to the right of the sun.
Image Credit: JHUAPL/SwRI
The planned search will involve targeting a small area of sky in search of a
Kuiper Belt object (KBO) for the outbound spacecraft to visit. The Kuiper Belt
is a vast debris field of icy bodies left over from the solar system's formation
4.6 billion years ago. A KBO has never been seen up close because the belt is so
far from the sun, stretching out to a distance of 5 billion miles into a
never-before-visited frontier of the solar system.
"I am pleased that our science peer-review process arrived at a consensus as
to how to effectively use Hubble's unique capabilities to support the science
goals of the New Horizons mission," said Matt Mountain, director of the Space
Telescope Science Institute (STScI) in Baltimore, Maryland.
Fully carrying out the KBO search is contingent on the results from a pilot
observation using Hubble data.
The space telescope will scan an area of sky in the direction of the
constellation Sagittarius to try and identify any objects orbiting within the
Kuiper Belt. To discriminate between a foreground KBO and the clutter of
background stars in Sagittarius, the telescope will turn at the predicted rate
that KBOs are moving against the background stars. In the resulting images, the
stars will be streaked, but any KBOs should appear as pinpoint objects.
If the test observation identifies at least two KBOs of a specified
brightness it will demonstrate statistically that Hubble has a chance of finding
an appropriate KBO for New Horizons to visit. At that point, an additional
allotment of observing time will continue the search across a field of view
roughly the angular size of the full moon.
Astronomers around the world apply for observing time on the Hubble Space
Telescope. Competition for time on the telescope is extremely intense and the
requested observing time significantly exceeds the observing time available in a
given year. Proposals must address significant astronomical questions that can
only be addressed with Hubble's unique capabilities, and are beyond the
capabilities of ground-based telescopes. The proposals are peer reviewed
annually by an expert committee, which looks for the best possible science that
can be conducted by Hubble and recommends to the Space Telescope Science
Institute director a balanced program of small, medium, and large
investigations.
Though Hubble is powerful enough to see galaxies near the horizon of the
universe, finding a KBO is a challenging needle-in-haystack search. A typical
KBO along the New Horizons trajectory may be no larger than Manhattan Island and
as black as charcoal.
Even before the launch of New Horizons in 2006, Hubble has provided
consistent support for this edge-of-the-solar system mission. Hubble was used to
discover four small moons orbiting Pluto and its binary companion object Charon,
providing new targets to enhance the mission’s scientific return. And Hubble has
provided the most sensitive search yet for potentially hazardous dust rings
around the Pluto. Hubble also has made a detailed map of the dwarf planet's
surface, which astronomers are using to plan New Horizon's close-up
reconnaissance photos.
In addition to Pluto exploration, recent Hubble solar system observations
have discovered a new satellite around Neptune, probed the magnetospheres of the
gas-giant planets, found circumstantial evidence for oceans on Europa, and
uncovered several bizarre cases of asteroids disintegrating before our eyes.
Hubble has supported numerous NASA Mars missions by monitoring the Red Planet's
seasonal atmospheric changes. Hubble has made complementary observations in
support of the Dawn asteroid mission, and comet flybys. In July 1994, Hubble
documented the never-before-seen string of comet collisions with Jupiter that
resulted from the tidal breakup of comet Shoemaker-Levy 9.
"The planned search for a suitable target for New Horizons further
demonstrates how Hubble is effectively being used to support humankind's initial
reconnaissance of the solar system," said Mountain. "Likewise, it is also a
preview of how the powerful capabilities of the upcoming James Webb Space
Telescope will further bolster planetary science. We are excited by the
potential of both observatories for ongoing solar system exploration and
discovery."
For images and more information about Hubble, visit:
and
NASA
Guillermo Gonzalo Sánchez Achutegui
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