Transcript Are there Planets outside the Solar System

Are there Planets outside the
Solar System ?
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First answer :
1992
Discovery of the first Extra-Solar
Planet around the pulsar
PSR1257+12 (Wolszczan &Frail)
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Are there Planets moving around other
Sun-like stars ?
The EXO Planet: 51 Peg b
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Mass: M sin i = 0.468
m_Jup
semi-major axis: a =
0.052 AU
period: p = 4.23 days
eccentricity: e = 0
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a of Mercury: 0.387 AU
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Discovered by:
Michel Mayor
Didier Queloz
Status of Observations
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292 Extra-solar planetary systems
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337 Planets near other solar-type stars
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33 Mulitple planetary systems
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43 Planets in binaries
Multi-planetary systems
Binaries
 Single Star and Single Planetary Systems
Interesting Questions
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How frequent are other planetary systems ?
Are they like our Solar System
(no.
of planets, masses, radii, albedos, orbital paramenters , …. )
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What type of environments do they have?
(atmospheres, magnetosphere, rings, … )
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How do they form and evolve ?
How do these features depend on the type of the
central star (mass, chemical composition, age, binarity, … ) ?
55 Cancri
5 Planeten bei 55 Cnc:
55Cnc d -- the only
known Jupiter-like
planet in Jupiterdistance
Binary: a_binary= 1000 AU
Extra-solare Planeten
ca.
130 Planeten entdeckt
massereich
enge
(~Mjup)
Umlaufbahnen
Radialgeschwindigkeits-
messungen
Mass distribution
Facts about Extra-Solar
Planetary Systems:
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Only 28% of the detected planets have
masses < 1 Jupitermass
About 33% of the planets are closer to the
host-star than Mercury to the Sun
Nearly 60% have eccentricities > 0.2
And even 40% have eccentricities > 0.3
Distribution of the detected Extra-Solar Planets
Mercury Earth Mars
Venus
Jupiter
Target Stars for
Darwin/TPF
315
stars
M
10 pc
K
G
Lifetime
A F
Temperature
Sources of uncertainty in parameter fits:
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the unknown value of the orbital line-of-sight inclination i allows us to
determine from radial velocities measurements only the lower limit of planetary
masses;
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the relative inclination ir between planetary orbital planes is usually unknown.
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In most of the mulitple-planet systems, the strong dynamical interactions
between planets makes planetary orbital parameters found – using standard
two-body keplerian fits – unreliable (cf. Eric Bois)
All these leave us a substantial available parameter space to be
explored in order to exclude the initial conditions which lead to
dynamically unstable configurations
Major catastrophe in less than 100000 years
SEMI-MAJOR AXIS
8.00
4.00
0.00
0
20000
40000
TIME (yr)
60000
(S. Ferraz-Mello,
Numerical Methods
Chaos Indicators:
(FLI)
Long-term numerical
integration:
C. Froeschle, R.Gonczi, E. Lega
(1996)
Stability-Criterion:
Fast Lyapunov Indicator
MEGNO
RLI
Helicity Angle
LCE
No close encounters within
the Hill‘ sphere
(i)Escape time
(ii) Study of the eccentricity:
maximum eccentricity
Multi-planetary systems
Binaries
 Single Star and Single Planetary Systems
OGLE 06-109L
Planet b: (0.71 +/-0.08 MJ)
a=2.3 +/-0.2 AU
e= ?
P = 1825 (+/- 365) d
Planet c: (0.27 +/- 0.03 MJ)
a = 4.6 (+/-0.5) AU
e = 0.11
i = 59 deg
P = 5100 (+/-730) d
www.univie.ac.at/adg/exostab/
ExoStab
appropriate for single-star single-planet system
- Stability of an additional planet
- Stability of the habitable zone (HZ)
- Stability of an additional planet with repect to the HZ
Stability of an additional planet
known parameters of system:
mass of star [M_sun]: 0.5
mass of giant planet [M_jup]: 0.21
semi-major axis of giant planet [AU]: 4.6
eccentricity of giant planet: 0.11
+/- error of eccentricity: 0.05
newly discovered planet:
Probable range of semi-major axis for the new planet:
semi-major axis of planet [AU]: 2.3
+/- error of semi-major axis: 0.2
Results of the
Exocatalogue
(Sandor et al., 2007)
The EXOCATALOGUE:
http://www.univie.ac.at/adg/
Details:
Sándor, Zs., Süli, A., Érdi, B., Pilat-Lohinger, E. and
Dvorak, R.: "A Stability Catalogue of the Habitable zones
in Extrasolar Planetary Systems", Monthly Notices of the
Royal Astronomical Society (MNRAS), 2006
Habitable Zone
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Zone around a star where liquid water can exist on
the surface of a terrestial-like planet
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This zone depends on:
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the spectraltype , the mass , the age, …. of the star
the orbit of the planet
the mass, the composition, the atmosphere , ……of the
planet
the parameters of other planets in this system (mass, orbit,
…)
Size of the habitable zone of a
planetary system
based on
the
definition
given by
Kasting et
al.
(1993).
Types of Habitable Zones:
(1) Hot-Jupiter type
(2) Solar system type
(3)+(4) giant planet type: habitable moon
or trojan planet
Stability maps
Inner region
(Solar system type)
Outer region
(Hot-Jupiter-type)
Computations
distance star-planet: 1 AU
variation of
- a_tp:[0.1,0.9] [1.1,4] AU
- e_gp: 0 – 0.5
- M_gp: 0 and 180 deg
- M_tp: [0, 315] deg
Dynamical model:
restricted 3 body problem
Methods:
(i) Chaos Indicator:
- FLI (Fast Lyapunov)
- RLI (Relative Lyapunov)
(ii) Long-term computations
- e-max
ANIMATION
How to use the catalogue
HD114729: m_p=0.82 [Mjup]
(0.93 [Msun])
a_p= 2.08 AU
e_p=0.31
m=0.001
HZ: 0.7 – 1.3 AU
m = 0.005
HD10697:
(1.15 Msun)
m_p= 6.12 [Mjup]
a_p = 2.13 AU
e_p = 0.11
HZ: 0.85 – 1.65 AU