Enceladus
Sara Faggy
Cédric Humbert
Catherina Jansen
Silvia Moriano
Pachigar Saumeel
What is Enceladus?
Athena and Enceladus.
Musée du Louvre, Paris, France
What is Enceladus?
The Astrophysical
Aspects
When did we first encounter Enceladus?
Cassini Mission
Cassini Mission
Astrophysical characteristics
Dimension: 252.1 ± 0.1 km =(0.0395 Earths)
Mass: (1.080 22 ± 0.001 01) × 1020 kg =(1.8×10-5 Earths)
Mean Density: 1.609 6 ± 0.002 4 g/cm3
Equatorial surface gravity: 0.111 m/s^2 (0.011 3 g)
Escape velocity: 0.239 km/s (860.4 km/h)
Rotation period: Synchronous
Axil tilt: Zero
Apparent Magnitude: 11.7
Surface temperature (mean) : 75K
Orbital parmeters
Major Axis
238 020 Km
Orbilat period
32 h 53 min 07s
Inclination (to Saturn's equator) 0,02°
Eccentricity
0,0045
The Biological
Aspects
Production of organic compounds by
interstellar cloud
CO
CO2
NH3
CH2OH
H2O
CH4
C2 and N2
and others organic compounds
Production of organic compounds by
interstellar cloud
Cosmic radiations (UV, gamma rays...))
CO
CO2
NH3
CH2OH
H2O
CH4
Production of organic compounds by
interstellar cloud
Cyanic acid
Formaldehyde
Alanine
Acetonitrile
Acetaldehyde
Ethylamine
Formamide
And other organic compounds.....
Enceladus
Meteorits and comets as carriers
Enceladus
Cosmic radiations
Degration/other chemical reactions
enanthioselective photolysis occurs during the voyage
Degradation / other chemical reactions/ enanthioselective photolysis/ and protection
Production of L-amino acids, D-sugars, nucleobase like compounds
and other precursors of biomolecules
L-amino acid (left) and D-amino acid (right)
Purine like compounds
Impact with the satelite and delivery of survival organic compounds on the crust
Production of organic compounds by volcanism
Production of organic compounds by
volcanism
Volcanism
Heating of sea salts
Production of HCL and
mineral ions
Catalysis of of follow reaction
+
Pyrrole
Formaldehyde
Dipyrrin redox active
metal ion chelator
Production of organic compounds by hydrothermal vents
Production of mineral ions
Production of simple molecules like CO2/H2/NO2....,
which form organic compounds
During the
freezing of water, solutes are excluded
and chemical reactions occur between the
solutes and produce some organic compounds
Production of biomolecules by clays
Adsorption of organic compound
by montmorillonite
Structure of montmorillonite
Production of organic compounds by
interstellar cloud
Montmorillonite are able to capture, retain, and protect
minerals due to their charged structure.
charged compounds and
This capacity of adsorption is due to a high cationic interchange capacity and an high area
of adsorption. These specificities of montmorillonite permit it to concentrate
biomolecules.
Montmorillonite presents an enantioselective uptake/protection of compounds, for
example montmorillonite retain preferencially L form of amino acids
This phenomenon permits some reactions such as the phosphorylation of AMP, amino
acids polymerisation of active nucleotides in RNA less than 50 mers (with a preferencial
bond formation between 2'-5' or 3'-5' positions) or formation of polypeptidic chain
sometimes by recruiting some mineral ions for catalysis.The mechanism for this is
temperature, pressure, and pH dependant.
Enceladus has the adequate conditions to permit such reactions.
What are Extremophiles?
‘Organisms that thrive in extreme
environments; if in more than one
extreme then called polyextremophiles’
Rothschild and Mancinelli
What are Extremes?
‘Everything in Moderation’
Aristotle
Group
Physical
Geochemical
Biological
Example
Temperature , Radiation or
Pressure
Desiccation, Salinity, pH
Nutritional extremes, Extremes
of population density.
Extremophiles in the case of Enceladus
Surface
Geothermal
Vents
Reservoir
and Core
• CH4, C02, N2 and H2O
atmosphere
• Temperature Avg. 75K
• Trace surface pressure
• Exposure to UV Rays
• Temperature Avg. 180K
• CH4, C02, N2, H2O, C3H8, C2H6
and C2H4
• Temperature Avg. 273K at water
reservoir
• Temperature Avg. In Core 1000K
Extremophiles in the case of Enceladus
Surface
- Minimal Atmosphere
-Very low Temperatures
-Dessication
- No oxygen
Geysers
-Varying temperature
- Pressure
- pH (Not confirmed)
Water Reservoir
- Has ideal conditions for life
Ecosystems on Enceladus
 We can describe two possible ecosystems that may exist on Enceladus.
Methanogen-based community
Sulfur reducing-based community
Primary producers are methanogens
that consume H2.
Primary producers are sulfurreducing
bacteria.
Ecosystems within a tidally heated
liquid water reservoir on Enceladus.
4H2 + CO2 → CH4 + 2H2O
4H2: from disotiation of H2O by
radioactive decay.
SO42-: reaction o oxidants with FeS2.
4H2+ H+ + SO42- → H2S+ 2H2O+ 2OH-
Ecosystems on Enceladus
 We can describe two possible ecosystems that may exist on Enceladus.
Methanogen-based community
Primary producers are methanogens
that consume H2.
Ecosystems within a tidally heated
liquid water reservoir on Enceladus.
Ice cover
Ocean
Biology: H2+CO2→CH4+H2O
H2
4H2 + CO2 → CH4 + 2H2O
Rock
CH4
CH4+H2O → H2+CO2
Ecosystems on Enceladus
 We can describe two possible ecosystems that may exist on Enceladus.
Methanogen-based community
Sulfur reducing-based community
Primary producers are methanogens
that consume H2.
Primary producers are sulfurreducing
bacteria.
Ecosystems within a tidally heated
liquid water reservoir on Enceladus.
4H2 + CO2 → CH4 + 2H2O
4H2: from dissotiation of H2O by
radioactive decay.
SO42-: reaction o oxidants with FeS2.
4H2+ H+ + SO42- → H2S+ 2H2O+ 2OH-
Origin of life on Enceladus
 Speculations about life on Enceladus are necessarily based on our
understanding of life on Earth.
Defining the growth requirements for life
- Liquid water
Enceladus has
- Energy source
all of these
- Carbon
- Other elements such as N, P, S.
Origin of life on Enceladus
Three main categories origin of life on Earth
Panspermia
Extraterrestial origin of life
Organic origin of life
Chemosynthetic origin of life
Terrestial origin of life
Origin of life on Enceladus
Panspermia
- Extraterrestrial origin of life.
-Enceladus would share the same origin and, therefore, the same biochemistry as
life on earth.
Organic origin of life
- Applied to Enceladus: the organic soup model might involve the formation of
Enceladus from organic-rich ices similar to cometary materials.
Chemosynthetic origin of life
- In this scenario, life begins at the interface where chemically rich fluids
heated by tidal dissipation emerge from below the sea floor.
The Technological
Aspects
Cassini Instruments:
-Cassini Plasma Spectometer (CAPS)
-Cosmic Dust Analyser (CDA)
-Composit Infrared Spectrometer (CIRS)
-Ion and Neutral Mass Spectrometer
(INMS)
-Imaging Science Subsystem (ISS)
-Dual techinque Magnetometer (MAG)
-Magnetospheric Imaging Instrument
(MIMI)
-Cassini Radar (RADAR)
-Radio and Plasma Wave Spectometer
(RPWS)
-Radio Science Subsystem (RSS)
-Ultraviolet Imaging Spectrograph (UVIS)
-Visible and Infrared Mapping
Spectometer (VIMS)
Ultra Violet Imaging Spectrograph
Ion and Neutral Mass Spectrometer
Visible and Infrared Mapping Spectrometer
Composite Infrared Spectrometer
Imaging Science Subsystem
The Future
Our Proposal
Enceladus at prensent is not completely understood, though the little data
collected from Cassini-Huygens shows promise for life.
Not being the current focus of the european and american space agencies, due
to commitments with studying Mars.
If a mission to enceladus ever arises we propose that the following are tested:
Test Water Reservoir
Check Plumes
-Bacterial By Products
-ATP
-Simple Sugars
Check for Sulphur
Thank you for your attention
References
Parkinson, C.D., Liang, M.C., Hartman, H., Hansen, C.J., Tinetti, G., Meadows, V.
Kirschvink, J.L. , Yung, Y.L. 2007. Enceladus: Cassini observations and implications for
the search for life. Astronomy&Astrophysics , 463: 353-357.
Porco, C. 2009. L’inquieto mondo di Encelado. Le scienze, 487: 42-51.
Postberg , F.,. Kempf , S., Schmidt, J., Brilliantov, J., Beinsen A. Abel , B., Buck, U.,
Srama, R. 2009. Sodium salts in E-ring ice grains from an ocean below the surface of
Enceladus. Nature, 459: 1098-1101.
Spencer, J.R., Pearl, J.C., Segura, M., Flasar, F.M., Mamoutkine, A., Romani, P., Buratti,
B.J., Hendrix, A.R., Spilker, L.J., Lopes, R.M.C. 2006. Cassini Encounters Eceladus:
Backgraund and the Discovery of south polar hot spot. Science, 311: 1401-1405.