A Guaranteed Time Programme with the Herschel
This page provides information for the community of the Guaranteed Time Key Programme (GT KP)
with the Herschel Space Observatory titled"Water
and Related Chemistry in the Solar System", also known as
The Herschel Space Observatory, a cornerstone mission in the European Space
Agency (ESA) science programme, was succesfully launched on 14th
May 2009 and will be operated as an observatory facility.
is the only space
observatory to cover the spectral range from far-infrared to
submillimetre wavelengths (approximately the 55-672 μm range).
It carries a 3.5 m diameter telescope and three
instruments: two cameras/medium resolution spectrometers (the
Photodetector Array Camera and Spectrometer
(PACS), and the Spectral
and Photometric Imaging REceiver (SPIRE)) and a very high resolution
heterodyne spectrometer (the Heterodyne Instrument for the Far
HssOhas 293.7 hours allocate during three years of routine science
observations, and will observeMars, the four Giant
Planets (Jupiter, Saturn, Uranus, and Neptune), the Saturn's moons Titan and Enceladus, and five comets (four known ones and one target of opportunity comet).
HssO addressesthe broad topic of water, its isotopologues, and related chemistry in planetary and cometary
atmospheres in orderto study their formation and
Water is ubiquitous in the Solar System,
being present in gaseous form in all planetary and cometary atmospheres, as
ice on the surface and subsurface of Mars, comets, most planetary satellites
and distant bodies, and in the liquid phase on Earth. Water plays an
important or dominant role in the chemistry of planetary and cometary
atmospheres. Comets are sources of water for planets through episodic
collisions and continuous production of ice-dust grains. This proposal
addresses the broad topic of water and its isotopologues in planetary and
cometary atmospheres. The nature of cometary activity and the thermodynamics
of cometary comae will be investigated by studying water excitation in a
sample of comets. The D/H ratio, the key for constraining the origin and
evolution of Solar System species, will be measured for the first time in a
Jupiter-family comet. A comparison with existing and new measurements of D/H
in Oort-cloud comets will constrain the composition of pre-solar cometary
grains and possibly the dynamics of the protosolar nebula. New measurements
of D/H in Giant Planets, similarly constraining the composition of proto-planetary
ices, will be obtained. The D/H and other isotopic ratios, diagnostic of
Mars' atmosphere evolution, will be accurately measured in H2O and CO.
The role of water vapor in Mars' atmospheric chemistry will be studied by
monitoring vertical profiles of H2O and HDO and by
searching for several other species. A detailed study
of the source of water in the upper atmosphere of the Giant Planets and
Titan will be performed. By monitoring the water abundance, vertical profile,
and input fluxes in the various objects, and when possible with the help of
mapping observations, we will discriminate between the possible sources of
water in the outer planets (interplanetary dust particles, cometary impacts,
and local sources). In addition to these inter-connected objectives,
serendipitous searches will enhance our knowledge of the composition of
planetary and cometary atmospheres.
Water (and related chemistry)
is present in the Solar System. Some spectacular examples are below:
In this High Resolution Stereo Camera (HRSC) 3D perspective view of
the Mawrth Vallis area on Mars (shades of grey),
OMEGA (Observatoire pour la Mineralogie l Eau les Glaces et l Activite) onboard Mars Express has mapped the water-rich minerals (blue). Credits:
Plumes of icy material extend above
the southern polar region of Saturn's moon Enceladus as imaged by the
Cassini spacecraft in February 2005.
The monochrome view is presented along with a colour-coded version on
the right. The latter reveals a fainter and much more extended plume
This clear-filter image was taken with the
Cassini spacecraft narrow-angle camera at a distance of approximately
321 000 kilometres from Enceladus. The image scale is approximately 1.8
kilometres per pixel. Credits: NASA/JPL/Space Science Institute.
The three small areas of water ice
on the surface of Tempel 1 appear in this image, taken by an instrument
aboard NASA’s Deep Impact spacecraft. Photo credit: NASA.
The presence of water vapour in the atmosphere of Titan is revealed by infrared emission at wavelengths of 39.37 and 43.89 microns. The European Space Agency's Infrared Space Observatory (ISO) observed Titan with its Short Wavelength Spectrometer during several hours of observations in December 1997, when Titan was at its farthest from Saturn.
Credits:Spectra: ESA/ISO/SWS and Coustenis/Salama et al. Photo:NASA / JPL
The "tiger stripes" on the Southpole
of Enceladus are the sources of ice particles and water vapor. Credits:
ASA / JPL / Space Science Institute
NASA's Cassini orbiter captured this view of Titan's Ontario Lacus from about 680 miles
(1,100 kilometers) away in December 2007.
A bright shoreline surrounds the hydrocarbon lake.
This makes Titan the only body in our solar system beyond Earth known
to have liquid on its surface.
Credits: NASA/JPL/University of Arizona.