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Gliederung

Gliederung. Populäre Einführung I: Astrometrie Populäre Einführung II: Hipparcos und Gaia Wissenschaft aus Hipparcos-Daten I Wissenschaft aus Hipparcos-Daten II Hipparcos: Technik und Mission Astrometrische Grundlagen Hipparcos Datenreduktion Hauptinstrument

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Gliederung

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  1. Gliederung • Populäre Einführung I: Astrometrie • Populäre Einführung II: Hipparcos und Gaia • Wissenschaft aus Hipparcos-Daten I • Wissenschaft aus Hipparcos-Daten II • Hipparcos: Technik und Mission • Astrometrische Grundlagen • Hipparcos Datenreduktion Hauptinstrument • Hipparcos Datenreduktion Tycho • Gaia: Technik und Mission • Gaia Global Iterative Solution • Wissenschaft aus Gaia-Daten • Sternklassifikation mit Gaia • SIM und andere Missionen

  2. Gaia: Wissenschaft

  3. GAIA: spatial distributions, motions, physical properties 1 billion stars to V=20 Key objective: composition, formation and evolution of the Galaxy Plus: thousands of other objectives

  4. Which stars can be observed ? Limit for 10-percent parallax

  5. Ergebnisse der Gaia-Mission (Schätzungen): Stern-Entfernungen auf 10 %: 150 Millionen (HIP: 21000) 1 %: 20 Millionen (HIP: 100 ?) 0.1 %: 1 Million (HIP: keine) Veränderliche Sterne: 50 Millionen (HIP: 8000) Astrometr. Doppelsterne: 100 Millionen (HIP: 3000) davon mit Bahnen: 100 000 (HIP: 235) Direkte Sternmassen auf 1%: > 10 000 (bisher ein paar Dutzend ? ) Weiße Zwerge: 200 000 (bisher ein paar hundert?) Braune Zwerge: 50 000 (bisher ein paar Dutzend) Planetensysteme: 50 000 (bisher 120) Supernovae: 100 000 (bisher einige tausend) Kleinplaneten: 500 000 ? (bisher 65 000) Relativitätstheorie auf 0.5 10-6 (bisher 50 10-6, oder 10 10-6 ? ) Vollständige Sternzählungen, genaue Sternzählungen, überall.

  6. 4000 4000 2000 2000 Heliocentric y coordinate Heliocentric y coordinate 0 0 -2000 -2000 -4000 -4000 -4000 -2000 0 2000 4000 Heliocentric x coordinate (pcs) -4000 -2000 0 2000 4000 Heliocentric x coordinate (pcs) Simulation of the Galactic plane (50000 OB stars) Photometric distances Gaia distances (Drimmel, Smart & Lattanzi, 1997)

  7. Halo accretion (Harding image) Halo Accretion(simulation: P. Harding)

  8. Tidal Streams in the Galactic Halo(simulation of accretion of 100 satellite galaxies)  GAIA will identify details of phase-space substructure

  9. Nebenbemerkung: kinematische Strukturen lassen sich sogar ganz ohnekinematische Daten entdecken. Beispiel: Gezeitenschwänze von Palomar 5,nur aus Mehrfarbenphotometrie mit Sloan Digitized Sky Survey. Gaia ist also nichtauf die Sterne mitguten Parallaxenbeschränkt. Mehrfarbenphoto-metrie gibt‘s füralle 109 Sterne! Odenkirchen et al., in:

  10. Example performance distance precision to members of the Hyades cluster Ground Hipparcos GAIA

  11. Binary and Multiple Stars • Constraints on star formation theories • Orbits for > 100,000 resolved binaries (separation > 20 mas) • Masses to 1% for > 10,000 objects throughout HR diagram • Full range of separations and mass ratios • Interacting systems, brown dwarf and planetary companions Photocentric motions: ~108 binaries Photometry: >106 eclipsing binaries Radial velocities: >106 spectroscopic binaries

  12. Astrometric detection of extra-solar planets : Solar motion at 100 pc Planet B Star 10 mas = hairwidh at 1000 km !

  13. Extra-solar planets: detection domainsfor astrometryand for radialvelocity

  14. Expected Exo-Planet Astrometric Discoveries • Monitoring of hundreds of thousands of F-G-K stars to 200 pc for 1MJ planets and P < 10 years: • complete census of all stellar types (P = 2-9 years) • masses, rather than lower limits (m sin i) • Large-scale detection and physical characterisation: 20,000- 30,000 planets expected to 150-200 pc e.g. 47 UMa: astrometric displacement 360 as • orbits for many (5000) systems (~ 30% to 100 pc) • mass down to 10 MEarth to 10 pc

  15. I HD 209458 - ap = 0.045 UA 1.00 0.99 0.98 Charbonneau et al., 1999 -0.1 days 0.1 P t t Photometric detection of extra-solar planets : transits I  0 inclination Central Efficiency unaltered by distance !

  16. GAIA: Studies of the Solar System Deep and uniform detection of all moving objects: • complete to 20 mag (well, not really, due to scanning law) • discovery of ~105 - 106 new objects (65,000 presently known) • taxonomy and mineralogical composition versus heliocentric distance • diameters for ~1000 asteroids • masses for ~100 objects • orbits: 30 times better than present, even after 100 years • Trojan companions of Mars, Earth and Venus • Kuiper Belt objects: ~300 to 20 mag + binarity + Plutinos • Near-Earth Objects: • e.g. Amors, Apollos and Atens (442: 455: 75 known today) • ~1600 Earth-crossing asteroids > 1 km predicted (100 currently known) • GAIA detection: 260 - 590 m at 1 AU, depending on albedo

  17. General Relativity/Metric • From positional displacements: •  to 510-7(cf. 10 -5presently)  scalar-tensor theories • effect of Sun: 4 mas at 90o; Jovian limb: 17 mas; Earth: ~40 as • From perihelion precession of minor planets: •  to 310-4 - 310-5 (10-100 better than lunar laser ranging) • Solar J2 to 10-7 - 10-8 (cf. lunar libration and planetary motion) • From white dwarf cooling curves: • dG/dT to 10-12 - 10-13 per year (cf. PSR 1913+16 and solar structure) • Gravitational wave energy: 10-12 < f < 10-9 Hz • Microlensing: photometric (~1000) and astrometric (few) events • Cosmological shear and rotation (cf. VLBI)

  18. Nebenbemerkung: Die Robertson-Parameter Sie modifizieren die Metrik um einen kugelymmetrischen Körper gegenüber der Allgemeinen Relativitätstheorie (ART): ART besagt: Brans-Dicke (eine alternative Gravitationstheorie) besagt: wobei w ein freier Parameter der Theorie ist Die klassischen Tests der ART: light bending ~(g+1)/2, radar delay ~(g+1)/2, geodetic precession of orbitinggyros ~(2g+1)/3, perihelion precession of planets ~(2-b+2g)/3. -> Gaia kann g und b bestimmen.

  19. Light Bending by Solar System Bodies

  20. Defining sources (212) Candidate sources (294) Other sources (102) ICRF: Source distribution

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