Extrasolar planets by dSJb4Al3

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									            Extrasolar planets




Emre Işık (MPS, Lindau)
S3 lecture
Origin of solar systems
14 February 2006
                      Outline
• Planet detection methods
   – Methodology
   – Some recent results
• Statistical properties of exoplanets
• Future prospects
Struve, O. 1952 Obs., 870, 199
         Detection techniques I
         Precise stellar radial
         velocities
                        to observer
N. Strobel
Detection techniques II
Transit photometry




Df / f = (Rp / R)2

pa = (PorbR) / Dt
  Detection techniques II
  Transit photometry
             Planets around binary stars


                                                         Advantages
                                                         • Easy (if automated!), small
                                                         telescopes with good sites/detectors
                                                         • Possibility to detect low-mass
                                                         planets, especially from space
Reflection effect
                                                         (Kepler mission, 2008)
                                                         Disadvantages
                                                         • Transit probability low;
                                                         simultaneous observations of many
                                                         stars
                                                         • Confusion with starspots, multiple
                                                         stars
                                           Deeg (1998)
   HST light curve of HD 209458 b




Brown et al. (2001)
                      • Stellar radius and limb-darkening profile
                      • Planet's mass and radius
                      • No rings around the planet
                      • No moons with M > 3 ME (repeated obs.)
Detection techniques III
    Microlensing
 Detection techniques III
Microlensing events
OGLE 2003-BLG-235/MOA 2003-BLG-53




                           Discovered planet:
                           1.5 MJ @ 3 AU

                   Bond et al. 2004, Astroph. J. Letters , 606 , L155
                     Detection techniques III
                     Microlensing events
 Discovery of a Cool Planet of 5.5 Earth Masses. OGLE-2005-BLG-390




                                                Discovered planet:
                                                5.5 ME @ 2.6 AU




Beaulieu et al., 2006, Nature, 439, 437
             Detection techniques IV
                   Astrometry




“Celestial” motion of the Sun due mainly to Jupiter &
     Saturn, as seen from 33 light years away…
Astrometry

A Jupiter analog orbiting 5 AU from a solar-type star produces an
astrometric amplitude of 0.5 milliarcsec (mas).

A star with planet close to (about 1 arcmin) to a star without planet is needed.

Direct, short CCD exposure at Palomar 5m and Keck telescopes may yield 0.1 mas.

Palomar test-bed interferometer yields 60-70 μas, VLTI should allow 20 μas.

Space missions may do better as interference from terrestrial atmosphere is eliminated.

As of 1998, no object has been found.

Technique is in its infancy. Big telescope resources are needed.
Detection techniques V
 Direct imaging !
        Detection techniques V
           Direct imaging !




Visible light             Infrared light
                Detection techniques V
                  Direct imaging !

• Name: 2M1207 b
• Msini: 5 ± 1 MJ
• Radius:1.5 RJ
• Temperature1240 ± 60 K
• Semi-major axis:
  (projected dist.) ~ 55 AU
• Orbital period: > 2450 yr
• Mass (star/M_sun): 0.025
                              NACO/VLT image, Chauvin et al. 2005
    Substellar companion to GQ Lupi

• IR image (NACO/VLT)
  GQ Lupi (A) orbited by
  a planet (b) at a distance
  of ~20xJupiter-Sun.
• GQ Lupi: 400 ly, 0.7 M
• Mass: 1-42 MJ
        Detection techniques VI
[reflection/absorption] spectroscopy
        Detection techniques VI
[reflection/absorption] spectroscopy
        Detection techniques VI
[reflection/absorption] spectroscopy
Caution: “planet occurrence” is biased by RV sensitivity!
Properties of the
detected planets




Lineweaver & Grether 2003
Properties of the
detected planets




Lineweaver & Grether 2003
Extrapolations




Lineweaver & Grether 2003
Lineweaver & Grether 2003
                     Evolutionary models




                                                               Fig.: Collier Cameron (2002)

• Different assumptions on the inhibition of cooling by irradiation from the parent star,
and the planet's internal structure (Burrows et al. [2000], Bodenheimer et al. [2001]
and Guillot and Showman [2002])
The future:
  Future of future:
     2015 - 2025




              O3
        CO2

								
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