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ASTROBIOLOGIAA vida no contexto
csmico
C. A. Wuensche
III Semana da Fsica - UFSCar07 de agosto de 2007
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Resumo
Introduo
Principais reas de discussoHabitabilidade planetria
ExoplanetasExtremfilos e origem da vida
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A Biophilic Universe
Martin Rees
Our Cosmic Habitat
A universe hospitable to life what we may call
a biophilic universe has to be very special in
many ways. The prerequisites for any life (long-lived stars, a periodic table of elements with
complex chemistry, and so on) are sensitive to
physical laws and could not have emerged from a
Big Bang with a recipe that was even slightly
different.
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A cosmological perspective tosearch of life in the Universe...
Spergel et al., WMAP series, 2006
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Other nonluminouscomponentsIntergalactic gas: 3.6%
Neutrinos: 0.1%Supermassive BHs: 0.04%
Luminous matterStars and luminous gas: 0.4%
Radiation: 0.005%
A cosmological perspective tosearch of life in the Universe...
Spergel et al., WMAP series, 2006
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Other nonluminouscomponentsIntergalactic gas: 3.6%
Neutrinos: 0.1%Supermassive BHs: 0.04%
Luminous matterStars and luminous gas: 0.4%
Radiation: 0.005%
A cosmological perspective tosearch of life in the Universe...
Life building blocks come
from these components...
Spergel et al., WMAP series, 2006
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Other nonluminouscomponentsIntergalactic gas: 3.6%
Neutrinos: 0.1%Supermassive BHs: 0.04%
Luminous matterStars and luminous gas: 0.4%
Radiation: 0.005%
A cosmological perspective tosearch of life in the Universe...
Life building blocks come
from these components...
b= 0.04 T
Spergel et al., WMAP series, 2006
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Other nonluminouscomponentsIntergalactic gas: 3.6%
Neutrinos: 0.1%Supermassive BHs: 0.04%
Luminous matterStars and luminous gas: 0.4%
Radiation: 0.005%
A cosmological perspective tosearch of life in the Universe...
Life building blocks come
from these components...
b= 0.04 T
Spergel et al., WMAP series, 2006
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Other nonluminouscomponentsIntergalactic gas: 3.6%
Neutrinos: 0.1%Supermassive BHs: 0.04%
Luminous matterStars and luminous gas: 0.4%
Radiation: 0.005%
A cosmological perspective tosearch of life in the Universe...
Life building blocks come
from these components...
b= 0.04 T
LETS GIVE IT UP!
Spergel et al., WMAP series, 2006
NOT!5
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Fundamental questions for
astrobiology How does life begin and evolve?
Does life exist elsewhere in the Universe?
What is the future of life on Earth and beyond?
From The Astrophysical Context of Life (http://www.nap.edu/catalog/
11316.html)
Astronomy provides the fundamental underpinnings for life: space
and time.
The Universe is filled with billions of galaxies, where there may
be possible sites for the origin and evolution of life.
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How can we define life?
Complex and diversified interactions with the environment
System out of thermodynamical equilibrium
Memory + reading/recovering mechanism
High information content and self-replication capability
Restrictive hipothesis... Complex systems? Liquid crystals, plasmas... Chemical system? C, Si?
Liquid millieu? Why H2O?
Existence of a solid/liquid interface?
J. Schneider, astro-ph/9604131, Szostak et al., Nature, 2001, Bains, Astrobiology 2005,
Lunine (2005)
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How can we define life?
Complex and diversified interactions with the environment
System out of thermodynamical equilibrium
Memory + reading/recovering mechanism
High information content and self-replication capability
Restrictive hipothesis...
Complex systems? Liquid crystals, plasmas... Chemical system? C, Si?
Liquid millieu? Why H2O?
Existence of a solid/liquid interface?
J. Schneider, astro-ph/9604131, Szostak et al., Nature, 2001, Bains, Astrobiology 2005,
Lunine (2005)
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How can we define life?
Complex and diversified interactions with the environment
System out of thermodynamical equilibrium
Memory + reading/recovering mechanism
High information content and self-replication capability
Restrictive hipothesis...
Complex systems? Liquid crystals, plasmas... Chemical system? C, Si?
Liquid millieu? Why H2O?
Existence of a solid/liquid interface?
J. Schneider, astro-ph/9604131, Szostak et al., Nature, 2001, Bains, Astrobiology 2005,
Lunine (2005)
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Galactic and Planetary
Habitability
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Cosmological and galactic issues
What sorts of environments are needed?
What is the adequate time span? Once formed,
planets evolve smoothly, but the same does nothold for our known life forms.
Initial Universe conditions, galactic and stellarevolution have spread out the building blocksfor life as we know it.
How biofriendly should a galaxy be, in order tofoster origin and evolution of life?
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Galaxy Formation Habitability
Galaxies are natural cells from which the Universe iscomposed.
Stars live in galaxies, and are responsible for the galacticchemical evolution.
Necessary levels of chemical abundances and radiation fieldsneeded for the rise of life
Early galactic evolution
starburstsdust and molecules complex chemistry.
CNO synthesized by stars in early galaxies allow for the
building blocks of organic chemistry to be present since theUniverse was ~ 200 million years.
Development of complexity life
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Lineweaver et al., Science, 303, 59 (2004)
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HABITABLE ZONE (68% e 95%)
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Probabilities for the GHZ
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b b l f h G
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Probability of star formation rate (SFR)
Typically 1 Solar Mass/year
Probabilities for the GHZ
13
P b bili i f h GHZ
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Probability of star formation rate (SFR)
Typically 1 Solar Mass/year
Probability of Forming Rock Planets (Pmetals)
Highly sensitive to the metallicity
Probability of destroying, producing and harboring Earths
Probabilities for the GHZ
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P b biliti f th GHZ
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Probability of star formation rate (SFR)
Typically 1 Solar Mass/year
Probability of Forming Rock Planets (Pmetals)
Highly sensitive to the metallicity
Probability of destroying, producing and harboring Earths
Probability of Evolution over Biological Timescales (Pevol)
Darwins theory requires long timescales
Pevoldepends on tevo (tevol = 4 Gyr for Earth)
tevol could be shorter than 4 Gyr?
Probabilities for the GHZ
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P b biliti f th GHZ
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Probability of star formation rate (SFR)
Typically 1 Solar Mass/year
Probability of Forming Rock Planets (Pmetals)
Highly sensitive to the metallicity
Probability of destroying, producing and harboring Earths
Probability of Evolution over Biological Timescales (Pevol)
Darwins theory requires long timescales
Pevoldepends on tevo (tevol = 4 Gyr for Earth)
tevol could be shorter than 4 Gyr?
Probability of Survival to Galactic Violent Events (PSN - Horvath e Galante,
Astrobiology 2006)
Pevoldepends on past events through tSN
For Earth, tSN = tevol = 4 Gyr (maybe shorter!)
Other killers: GRBs, GMClouds, AGNs
Probabilities for the GHZ
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Friaa et al., ApJ 2006 (submitted)
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R t d t ti f PANH i th IR
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H
C
N
Recent detection of a PANH in the IRHudgins et al. ApJ, 2005
Spitzer detected PANHs in various galaxies, besides our own. First direct evidence for the presence of a prebiotic interesting compound in
space. Presence of N is essential in biologically interesting compounds (chlorophyll). The presence of a planet is no longer necessary for the formation of a PANH.
Component of caffeine
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Stellar habitable zone
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Stellar habitable zone
R
Main assumptions: Surface H2O for ~ Gyear, geological activity, CO2-H2O-N2
atmosphere, B-field, climate stability, resistance to catastrophes for ~ Gyear
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Stellar habitable zone
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Stellar habitable zone
R
Main assumptions: Surface H2O for ~ Gyear, geological activity, CO2-H2O-N2
atmosphere, B-field, climate stability, resistance to catastrophes for ~ Gyear
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IRS-46 spectrumhttp://www.nasa.gov/lb/vision/universe/starsgalaxies/spitzer-20051220.html
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IRS-46 spectrumhttp://www.nasa.gov/lb/vision/universe/starsgalaxies/spitzer-20051220.html
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IRS-46 spectrumhttp://www.nasa.gov/lb/vision/universe/starsgalaxies/spitzer-20051220.html
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Formation and evolution of life
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~ 90% of all Earths biomass!
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Catling
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O i f E th h bit bilit
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Our recipe for Earth s habitability
1)Liquid water allowed microbes to originate and evolve
2)Plate tectonics replenished CO2
for life to persist
3)A magnetic field protected atmospheric gases fromescape (except H, He)
Microbes made O2, CH4 CH4 then O2 dominated
Ozone layer formed at ~ 2.3 Gy
Simple algae, fungi developed
More O2 and animals at 0.6 Gy Modern humans at 2 My
This seminar...
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Exoplanets
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203 planetas175 sist. planetrios
20 sistemas mltiplos
4 planetas
4 planetas
4 planetas
ltimo acesso: 27/07/2007
Fonte: http://www.obspm.fr/encycl/catalog.htmlCapacidade existenteProjetada (10 20 a)
Deteces primrias
Acompanhamentos
N-sistemas? - Incertezas
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All Catalogs (update : 27 July 2007)
http://www.obspm.fr/encycl/catalog.htmlhttp://www.obspm.fr/encycl/catalog.htmlhttp://exoplanet.eu/catalog-all.php8/2/2019 Talk Astrobiologia Ifusp2007
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All Candidates detected248 planets
Candidates detected by radial velocity 202 planetary systems
(update: 09/07/2007) 236 planets
25 multiple planet systems
Candidates detected by transit 23 planetary systems
(update: 09/07/2007) 23 planets
0 multiple planet systems
Candidates detected by microlensing 4 planets
update : 10/06/2006
Candidates detected by imaging 4 planets
update : 24 /07/2006
Candidates pulsar planets 2 planetary systems
update : 15/10/2006 4 planets1 multiple planet system
- Unconfirmed, controversial or retracted planets: 2
update : 06 July 2007
- Candidate "cluster" and "free-floating" planets: 3
update : 31 August 2006
http://exoplanet.eu/catalog.php
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Main techniques
http://exoplanet.eu/cat-freefl.htmlhttp://exoplanet.eu/catalog-pulsar.phphttp://exoplanet.eu/catalog-imaging.phphttp://exoplanet.eu/catalog-imaging.phphttp://exoplanet.eu/catalog-microlensing.phphttp://exoplanet.eu/catalog-microlensing.phphttp://exoplanet.eu/catalog-transit.phphttp://exoplanet.eu/cat-freefl.htmlhttp://exoplanet.eu/cat-freefl.htmlhttp://exoplanet.eu/catalog-contro.phphttp://exoplanet.eu/catalog-contro.phphttp://exoplanet.eu/catalog-pulsar.phphttp://exoplanet.eu/catalog-pulsar.phphttp://exoplanet.eu/catalog-imaging.phphttp://exoplanet.eu/catalog-imaging.phphttp://exoplanet.eu/catalog-microlensing.phphttp://exoplanet.eu/catalog-microlensing.phphttp://exoplanet.eu/catalog-transit.phphttp://exoplanet.eu/catalog-transit.phphttp://exoplanet.eu/catalog-RV.phphttp://exoplanet.eu/catalog-RV.phphttp://exoplanet.eu/catalog-all.phphttp://exoplanet.eu/catalog-all.php8/2/2019 Talk Astrobiologia Ifusp2007
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Main techniques
Radial velocity (187 planets) Both planets spin around the center of mass of the system.
The larger the planet mass or the smallest the distance between starand planet, the larger the star movement.
Transit (9 planets) Orbits practically perpendicular to the plane of the sky (i=90o). The planet mass is determined by radial velocity; the transit tells us
about the radius.
Telescopes on the ground are able to detect only large planets; for
Earth-like planets, satellite observations are required.
Microlensing (4 planets) Gravity due to an object between the source and us bends the ligth of
the source
Massive objects in the Galactic halo may act as gravitational lens.25
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Radial Velocity
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Gravitational
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Transit of extrasolar planets
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p
http://www.iac.es/galeria/hdeeg/OSNanimlastmont.gif
~0,02
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Kepler
http://www.iac.es/galeria/hdeeg/OSNanimlastmont.gifhttp://www.iac.es/galeria/hdeeg/OSNanimlastmont.gifhttp://www.iac.es/galeria/hdeeg/OSNanimlastmont.gif8/2/2019 Talk Astrobiologia Ifusp2007
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Darwin
TPF (Terrestrial Planet Finder)
COROTcom 30% de participao
brasileira (INPE tambm)!
30
Possibility of remote detection of lifeExplore the contrast star/planet in thermal IR (Des Marais et al 2002 Segura et al 2003)
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Explore the contrast star/planet in thermal IR(Des Marais et al. 2002, Segura et al. 2003)
> 106
Porto de Melo et al., Astrobiology, 2006
CO2
15 m
O3
9.6 m
CH4
7.7 m
H2O
6.3 m +
12 m band
Window at 8-12 m: Tsurface
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A. Chian presented a technique to detect exoplanets via radio emission.Coronal Mass Ejections (CME) from a stellar active region may cause
geomagnetic storms, which can be seen at large distances. Chian
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Extremophiles and the
origin of life
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Temperature limits for lifea
ry2001)
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The highest and lowest temperature for each major taxon is given. Archaea are in red, bacteria in blue,
algae in light green, fungi in brown, protozoa in yellow, plants in dark green and animals in purple.Lifeinextremeenvironme
nts,
LJRothschild&RLMancinelli,Nature409,
1092-
1101(22Februa
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Extremophiles who are they?
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t e op es w o a e t ey?
We have more microbe cell than us-cells in our body.
The first life form on Earth, and the only one for the
first 3 billion years, was a microbe.
Microbes can live in REALLY extreme conditions.
There is more life within the Earth (a few feet below)
than on the Earths surface.
Most probable candidates to an E.T. life form.
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Extremophiles who are they?
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p y
We have more microbe cell than us-cells in our body.
The first life form on Earth, and the only one for the
first 3 billion years, was a microbe. Microbes can live in REALLY extreme conditions.
There is more life within the Earth (a few feet below)
than on the Earths surface.
Most probable candidates to an E.T. life form.
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Extremophilessurvival chart
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Temperature: -15 C < T < 230 C 0.06 < pH < 12.8
0 < Pressure < 1200 atm
No mandatory oxygen-based metabolism
20-40 Myears of dormancy
2
years in space, at 20 K, with nonutrients, water and exposed to radiation
(Strep. Mitis)
survival chart
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http://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htmhttp://willmclaughlin.astrodigitals.com/Antarctica/Dry_360.htm8/2/2019 Talk Astrobiologia Ifusp2007
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Adapted from F. Souza-Barros, 2006
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Adapted from F. Souza-Barros, 2006
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What is being done in Brazil?
Astronomy
Biology
Chemistry
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Survival of aminoacids and nucleobases in ISM andIPM (Pilling et al., 2006)
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20 Amino acids
Glycine Alanine Valine
Leucine
Serin Glutamine
Lysine
Asparagine
Arginine
Glutamicacid
Asparticacid
Isoleucine
Threonine
IPM (Pilling et al., 2006)
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Our heroes
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20 Amino acids(cont)
CysteineMethionine
Proline
TryptophanePhenylalanine
Histidine
Tyrosine
Hidroxylamine
Detected precursor molecules!
Acetic acid
Formic acid
Methanolamine
NH2CH2
NH2CH
NH
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Our heroes
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5 Nucleobases
Adenine GuanineCytosine ThymineUracil
Pyrimidines Purines
PyrimidinePyridine
Detected precursor molecules!
Hydrogen
Cyanide
Acetylene Purine
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How they are born?
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X-ray
UV
UV
HCOOH
HCOOH
X-ray
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How they are found?
IR Telescopes ( b l l )
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Radiotelescopes (rotational lines)
IR-Telescopes (vibrational lines)
Itapetinga, SP
VLA
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How they are found?
IR Telescopes ( ib i l li )
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Radiotelescopes (rotational lines)
IR-Telescopes (vibrational lines)
Itapetinga, SP
VLA
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Gaseous Pillars Eagle Nebula Key hole Nebula
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Hale-Bopp MurchinsonTitan
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Photoionization using synchrotron light
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TGM e SGM bean line (VUV & soft X-ray)
12-22eV
C1s (290eV)
N1s (410eV)
O1s (540ev)
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The technique
i f li h S O S
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Time-of-Flight Mass Spectometry; TOF-MS
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Where arethe nucleobases?
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Where are the nucleobases?
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Why we don't observe them?
Main reasons for no detection. Life time to short to sustain the column density above
the detection limit. Low resistance to radiation field.
Low efficient pathway formation. Low density Large partition function. Many ro-vibrational lines with
low intensity.
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Where are the nucleobases?
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Why we don't observe them?
Main reasons for no detection. Life time to short to sustain the column density above
the detection limit. Low resistance to radiation field.
Low efficient pathway formation. Low density Large partition function. Many ro-vibrational lines with
low intensity.
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Where are the nucleobases?
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Why we don't observe them?
Main reasons for no detection. Life time to short to sustain the column density above
the detection limit. Low resistance to radiation field.
Low efficient pathway formation. Low density Large partition function. Many ro-vibrational lines with
low intensity.
If we'll go there, and look for them using amicroscope or other device?
48
Biomolecules results
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Amino acids
survival: ~ 1% (16 eV); 0% (> 20 eV )
main photoproducts (Fingertips): COOH, HCNH, ...
Nucleobases
survival: ~ 30% (16 eV); ~ 20% (20eV ); ~ 0.5% (> 100eV)
main photoproducts: HNCO, HCN, NCO, ...
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Biomolecules results
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Amino acids
survival: ~ 1% (16 eV); 0% (> 20 eV )
main photoproducts (Fingertips): COOH, HCNH, ...
Nucleobases
survival: ~ 30% (16 eV); ~ 20% (20eV ); ~ 0.5% (> 100eV)
main photoproducts: HNCO, HCN, NCO, ...
Lets try to look for these guys using their parts(pieces)?
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SEARCHING PERSPECTIVES
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Follow-up of growth & metabolism ofextremophiles under simulated planetary/satellite conditions
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Tit
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Lago de Hidrocarbonetos?
Rios de Metano?
Niemam et al. 2005, Nature, 438, 779.
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ASTROBIOLOGICALLY INTERESTINGSTARS NEAR THE SUN
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Porto de Mello et al., Astrobiology, 6, 308-331 (2006)
Goal: to establish state of the art criteria for selectingstars which might be hosts to remotely detectable
biospheres
Criteria: Liquid water, geologic activity, long term
climate stability
stellar mass, stellar chemical
composition, stellar age
Adequate Time Scales:
bioproductivity timescale, oxygenationtime scale, stellar age
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Continuously Habitable Zone and Timescales
The Habitable Zone ConceptANALYSIS
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Continuously Habitable Zone and Timescales
The Habitable Zone ConceptANALYSIS
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Upper mass limitM ~ 1.2 solar
masses
Lower mass limit
M ~ 0.7 solarmasses
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The Bioproductivity Issue
The Habitable Zone ConceptANALYSIS
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Age of highlydiversified
biosphere
is less than 20%
of total biospherelifetime
Too advancedan ageis a liability
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The 13 biostars within 33 light-years
HD Name mass age [Fe/H] orbit rank
NOT ONE OF THEM WITH PLANETS !RESULTS
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g [ ]
1581 Tuc ~ ~ ~ > 4628 < ? < ~
10476 107 Psc < ? < >
16160 < ? ~ >
32147 < ~ > >
100623 < > < >
102365 < > < >
109358 CVn > ~ < ~
115617 61 Vir ~ ~ ~ >
185144 Dra < > < >190248 Pav > ~ > ~
192310 < > ~ >
219134 < ? ~ >
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Present results
WE CAN quantitatively rank nearby stars as astrobiological
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q y y g
targets : completeness of available data is essential;
7% of neighborhood stars are interesting;
2% only if we take galactic orbits as relevant;1% only is actually similar to the Sun;
Observational and theoretical work should continue on:
Completeness of stellar database of nearby objects;Habitability ofmultiple stars;
Stabilityof biospheres againstgalactic catastrophes;
Habitability criteria for planets different from the Earth;
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Any alternatives at this point?
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Other liquids may define other biochemistries Ammonia (Jupiter satellites), methane/ethane
(Titan), nitrogen (silicon-oriented)
Light (mostly IR) on the surface of Titan may allow
photosynthesis-like processes, even at lowtemperatures.
Chemolitotrophy possibly available in any liquid
environment (Galilean satellites).
Maybe a new definition of Galactic and Stellar
Habitable Zones? (Wuensche, Lage, et al.,Astrobiology 2006, submitted)
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OUR SOLAR SYSTEMS
LIQUID POSSIBILITIES
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Water-based oceans
Other liquid possibilities
water/am
monia
(surf
acelake
s)
water/am
monia
(sub
surfac
e)
meth
ane/etha
ne
(surfacelakes
)
nitrog
en(su
rface)
nitrog
en(su
bsurfa
ce)
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Carbon based, DNA-like search, in planetary systems
Targeting small constituents of organic compounds Radio/IR/
X (Pilling et al., A&A 2005)
Targeting PANHs IR (Hodges et al., ApJ 2005)
Other alternatives (chemical/physical/meteorological)
Other liquids/fluids demand a different chemistry (not CHON
based) due to thermodynamical requirements (Bains,
Astrobiology 2005).
Self-sustained ability to disturb a local environment
(Atmosphere search for upcoming space missions).
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