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Various information from different detection methods. André. Outline. Introduction Indirect detection techniques Radial Velocity Astrometry Transit Microlensing Direct detection techniques Reflected starlight Imaging. FLO. Introduction. so far 215 planets are detected (23.03.2007)
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Various information from different detection methods MPIA-Student-Workshop, Italy
André Outline • Introduction • Indirect detection techniques • Radial Velocity • Astrometry • Transit • Microlensing • Direct detection techniques • Reflected starlight • Imaging FLO MPIA-Student-Workshop, Italy
Introduction • so far 215 planets are detected (23.03.2007) • 21 multiple systems • first announcements: Peter van de Kamp (18.04.1963) • Astrometric study of Barnard‘s star from plates taken • with the 24-inch Sproul refractor(AJ, vol. 68, 515) • BUT: 1952 by Otto Struve: • Proposal for a project of high-precision stellar radial • velocity work (The Observatory, No. 870) • first detections: • 1995 by Mayor & Queloz: 0.5 MJupiter • P = 4.2 days around 51 Peg MPIA-Student-Workshop, Italy
Orbital parameters Period P Semi-mayor axis a Eccentricity e Inclination i Argument of perihelion ω Longitude of the acsending node Ω True anomaly T Time of periapsisτ MPIA-Student-Workshop, Italy
Indirect techniques - radial velocity measurements • 203 planets 175 Planetary systems, 20 systems with > 1 planet 94,4% • Doppler Wobble • Hot Jupiters mostly MPIA-Student-Workshop, Italy
RV time series of the young G0V star ιHor Kürster et al. 2000, A&A 353, L33 Requirements • High measurement precision ~ 1m - 20 cm/s • Stability over ~ 10 years • Derived orbital parameters • P, e, a, T, ω Msini MPIA-Student-Workshop, Italy
- Astrometry • So far 8 planets: • Gl 876: 2 planets • 55 Cnc: 4 planets • ε Eri • Wobble around center of mass due to planet • Law of the lever: Θs = mp/ms. ap/d • Limits: 1-2 mas (ground based) 0.1 mas (HST FGS) • need for interferometrie for high precision PRIMA • Constraints: nearby stars, not too close to the star • can derive inclination and mass of planetary companion MPIA-Student-Workshop, Italy
2008 2007 What do I observe? • I see the overlay of three different motions: • Proper motion MPIA-Student-Workshop, Italy
2008 2008 2007 What do I observe? • I see the overlay of three different motions: • Proper motion • Parallax MPIA-Student-Workshop, Italy
2008 2007 20 What do I observe? • I see the overlay of three different motions: • Proper motion • Parallax • Planetary signal • need to measure all 3 motions accuratly • Derived parameters: α, i, Ω, μ, π, T true mass of companion MPIA-Student-Workshop, Italy
Jupiter as an example For a star at 10 pc distance: MPIA-Student-Workshop, Italy
And what about AO effects? • maybe there remains a residual defocus or other distortions • one need a reference pattern of background-stars to determine the • platescale and changes due to instrumental effects MPIA-Student-Workshop, Italy
And what about AO effects? • maybe there remains a residual defocus or other distortions • one need a reference pattern of background-stars to determine the • platescale and changes due to instrumental effects • but the background-stars can have their own pm and parallax MPIA-Student-Workshop, Italy
Transits Venustransit June 2004 MPIA-Student-Workshop, Italy
Transits • Photometric detection • Depth of lightcurve yields planet-radius (~ 1% for Jupiter) Tres-1 HD209458 MPIA-Student-Workshop, Italy
Transit • Parameters derived: P, T0, i ~ 90°, Rp/RS • Together with the mass of the planet from RV measurements one can derive the density of the planet MPIA-Student-Workshop, Italy
Microlensing • Principle: MPIA-Student-Workshop, Italy
D. Bennett Microlensing • Principle: • Magnification due to Star and planet acting as lenses MPIA-Student-Workshop, Italy
Microlensing • Principle: • Magnification due to Star and planet acting as lenses • First planet: Bond et al. (04.2004) MPIA-Student-Workshop, Italy
BUT: • No way of confirmation • Single event • Short timescale: hours - days • Results: 4 detections as of today MPIA-Student-Workshop, Italy