Download The Search for Reflected Light

What do we know about
the exo-planets?
&
How to detect direct signals
from exo-planets?
Florian Rodler
22 May 2017
what do we know from the exo-planets?
Introduction
(1) 201 confirmed planetary candidates + 14 confirmed planets
found around solar-like stars and pulsars
(in 175 planetary systems)
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22 May 2017
what do we know from the exo-planets?
Introduction
(1) 201 confirmed planetary candidates + 14 confirmed planets
found around solar-like stars and pulsars
(in 175 planetary systems)
-
RV: only minimum mass:
MPlanet_min = MPlanet sini
-
microlensing: estimation
of planetary mass
-
transit + RV: i ≈ 90°.
Exact mass determination
possible: MPlanet_min = MPlanet .
→ companion a brown
dwarf (M>13 Mjup) ?
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22 May 2017
what do we know from the exo-planets?
Introduction
(1) 201 confirmed planetary candidates + 14 confirmed planets
found around solar-like stars and pulsars
(in 175 planetary systems)
exact determination
of mass needed!!!
-
transit + RV: i ≈ 90°.
Exact mass determination
possible: MPlanet_min = MPlanet .
- astrometry (→ future)
- transit + RV
- direct imaging
- reflected light (+RV)
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22 May 2017
what do we know from the exo-planets?
Introduction
(2) Some do we know about these planets?
- Planetary masses (mostly Mplanet_min): 6 MEarth – 13 MJupiter
(most planets > 0.5 MJupiter)
- very close to host star: 0.03 – 60 AU
(most planets < 0.1 AU: hot Jupiters)
Hot Jupiter
Mercury
0.5 AU
22 May 2017
what do we know from the exo-planets?
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Introduction
(2) Some parameters of the planets found:
- Planetary masses (mostly Mplanet_min): 6 MEarth – 13 MJupiter
(most planets > 0.5 MJupiter)
- very close to host star (0.03 – 6 AU)
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22 May 2017
what do we know from the exo-planets?
Introduction
(2) Some do we know about those planets?
- Planetary masses (mostly Mplanet_min): 6 MEarth – 13 MJupiter
(most planets > 0.5 MJupiter)
- very close to host star: 0.03 – 60 AU
(most planets < 0.1 AU: hot Jupiters)
- planets are heated up: radii are large (transits!)
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22 May 2017
what do we know from the exo-planets?
Introduction
(2) Some do we know about those planets?
- Planetary masses (mostly Mplanet_min): 6 MEarth – 13 MJupiter
(most planets > 0.5 MJupiter)
- very close to host star: 0.03 – 60 AU
(most planets < 0.1 AU: hot Jupiters)
- planets are heated up: radii are large (transits!)
- planetary atmospheres (transits, direct imaging, reflected light)
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22 May 2017
what do we know from the exo-planets?
Introduction
(2) Some do we know about those planets?
- Planetary masses (mostly Mplanet_min): 6 MEarth – 13 MJupiter
(most planets > 0.5 MJupiter)
- very close to host star: 0.03 – 60 AU
(most planets < 0.1 AU: hot Jupiters)
- planets are heated up: radii are large (transits!)
- planetary atmospheres (transits, direct imaging, reflected light)
"Direct methods"
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22 May 2017
what do we know from the exo-planets?
"Direct methods“
... detecting a direct
signal from the planet
(a) transits
(b) direct imaging
(c) reflected light
(d) other stuff ...
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22 May 2017
what do we know from the exo-planets?
Transits
Atmosphere of the planet around HD 209458 (Charbonneau … 2001)
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22 May 2017
what do we know from the exo-planets?
Transits
TrES-1: thermal signature
of atmosphere found
(Charbonneau ... 2005)
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22 May 2017
what do we know from the exo-planets?
Direct imaging
Planet 2M1207 (Chauvin ... 2005)
Star-planet flux ratio decreased
- for young objects (self-lum.)
- in the NIR
Close-in planets can hardly be
imaged (< 0.1“)!
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22 May 2017
what do we know from the exo-planets?
Planet 2M1207 (Chauvin ... 2005)
Flux
Direct imaging
Star-planet flux ratio decreased
- for young objects (self-lum.)
- in the NIR
wavelength (micron)
Flux
Close-in planets can hardly be
imaged (< 0.1“)!
wavelength (micron)
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Burrows ... 2003)
22 May 2017
what do we know from the exo-planets?
Reflected Light :: Motivation
Jupiter – Sun flux ratio in the
visual : 1/250 000 000 (seen from outer
space)
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22 May 2017
what do we know from the exo-planets?
Reflected Light :: Motivation
Jupiter – Sun flux ratio in the
visual : 1/250 000 000 (seen from outer
space)
hot Jupiters
Hot Jupiters are 100x closer: 0.05 AU
E
J
→ planet-star flux ratio ≈ 1/25 000 for
a Jupiter sized planet!?
0.05
0.5
5 [AU]
log distance from host star
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22 May 2017
what do we know from the exo-planets?
Reflected light
High resolution, high S/N spectroscopy
of star + planet in the visual!
→ approx. 2300 stellar absorption lines +
→ these lines reflected by the planet, BUT
- Doppler shifted due to orbital motion
- faint (a few times 1/10000 )
→ looking for the same pattern in the spectra:
each stellar spectral line has its reflected
counterpart ...
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22 May 2017
what do we know from the exo-planets?
schematics ...
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22 May 2017
what do we know from the exo-planets?
Reflected light
Requirements
Hot Jupiter Mercury
• bright host stars (spectroscopy!)
• hot Jupiters (periods of 3-5 days)
• and lots of data (S/N)!
0.5 AU
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22 May 2017
what do we know from the exo-planets?
Reflected light
What will we learn ...
... once we detect reflected light?
• orbital inclination (+RV)
→ exact planetary mass
• information about planetary
atmosphere → input for theory!
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22 May 2017
what do we know from the exo-planets?
Reflected light
Find planetary signature:
chi2 minimisation
→ calculate fits for
K and contrast
→ best fit for planet
→ significance of
detection: MC
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22 May 2017
what do we know from the exo-planets?
Conclusions on direct methods
(a)transits
 atmospheres (VIS, IR), young and old
 radii
 moons!?
 i ≈ 90°
(b) direct imaging
 atmospheres (IR), young objects only
 not close to star
(c) reflected light
 atmospheres (VIS), old objects only
 very close to star
 bright objects
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22 May 2017
what do we know from the exo-planets?
some stuff about Florian Rodler ...
Studies at Vienna observatory (1997 - ???), Austria
PhD student at MPIA, supervised by Martin Kürster
Topics of interest:
beer & dancing
atmospheres of exo planets, direct detections
pulsating stars
observing
Hobbies:
hiking
travelling
painting
biking tours
...
22 May 2017
what do we know from the exo-planets?