Abschätzung für unser Sonnensystem

Transcription

1 Transit Surveys

2 Abschätzung für unser Sonnensystem Planet Umlaufzeit Transitdauer ΔF Wahrscheinlichkeit [Jahr] [Stunde] [%] [%] Merkur Erde Jupiter Neptun Exoplanet ~1 ~10 => Beobachtung vieler Sterne über einen längeren Zeitraum

3 This is where we have to be clever : N * : Detection probabilities To detect 1 transit N T we need to multiply the total number of detected stars in a target field, N stars, by: Things we can do nothing about : P g : Fraction of systems seen edge-on f: Fraction of stars with giant planets Something that just needs patience : P cov : N T = N stars P g f P cov N * coverage of a planet s orbit by observations Number of useful stars in the field-of-view with sufficient S/N depends on: instrument, observing conditions, photometry, field binary stars N * = N dwarf N S/N selection,

4 What Telescope to pick? FoV (the bigger the better) Magnitude range (go for the brightest?) Number of Stars (the more the merrier) Other factors: CCD high QE low noise Stable over long timescales Readout time Alignement working

5 Crouzet et al.

6 Kriterien zur Feldauswahl Wie kann man die Anzahl entdeckter Transitkandidaten maximieren? Beobachtungszeit (Feld möglichst lange sichtbar) Messgenauigkeit (Geringe Luftmasse) Anzahl der Sterne (Möglichst viele Sterne) Folie 6

7 Folie 7 Seminarvortrag > Thomas Fruth >

8 Folie 8 Seminarvortrag > Thomas Fruth >

9 Folie 9 Seminarvortrag > Thomas Fruth >

10 Folie 10 Seminarvortrag > Thomas Fruth >

11 Feldauswahl quantitativ Folie 11

12 Folie 12 Seminarvortrag > Thomas Fruth >

13 The first planetary transits the search for transits of known extrasolar planets discovered by radial velocity the first transit observed the photometric search for transiting extrasolar planets the first planet detected by the method of transits arbonneau et al ApJ, 529, L45 But planet was known before from radial velocity survey Udalski et al AcA, 52, 115 confirmed by RV by Konacki et al Nature, 421, L508

14 STARE (STellar Astrophysikcs & Research on Exoplanets) HD209458b: Umlaufzeit = 3.52 Tage Radius = 1.3 Jupiterradien Masse = 0.63 M Jupiter Dichte = kg/m 3 (Charbonneau et al., 2000; Brown and Charbonneau 2000) STARE: Aperture Telescope FOV CCD Scale Filter Location 10 cm Schmidt Cassegrain 6 x 6 degree 2034x2034 pixel 10 arcsec/pixel Johnson R Bolder since 2001 Tenerife

15 OGLE Chile 1.3m telescope 8 detectors (2kx4k) 35x35 arcminutes 0.26"/pixel 8 Planets detected MV: Depth: 0.5% - 2.2% Periods: days

16 TrES TrES: Trans-atlantic Exoplanet Survey (STARE is a member of the network) Three 10cm telescopes located at Lowell Observtory, Mount Palomar and the Canary Islands 5 Planets detected MV: Depth: 1% - 3% Periods: days TrES-1b Alonso et al. 2004

17 XO Haleakala on Maui, Hawaii. twin 200mm Canon EF200 lenses at f/1.8. Apogee Ap8p CCD detectors (1024x1024) 24µm pixels. 7.2 square degrees 25.4"/pixel 5 Planets detected MV: Depth: 0.5% - 1.7% Periods: days

18 FLWO Arizona & Mauna Kea Six lenses (Takahashi) Apogee E10 detectors (2kx2k) 1.3x1.3 degrees per CCD 4.6"/pixel HATNet South: 2x4 lenses Since 2009 Australia / Chile 33 Planets detected MV: Depth: 0.43% % Periods: days HATNet

19 La Palma & South Africa 2x 8 lenses (Canon 200mm f/1.8) e2v detectors (2kx2k) 7.8x7.8 degrees per CCD 13.7"/pixel 67 Planets detected MV: Depth: 0.6% - 2.4% Periods: days SuperWASP

20 CoRoT Space 27cm mirror system 4 detectors (2kx2k) 2.7x3.0 degrees 21 Planets detected MV: Depth: 0.04% - 2.6% Periods: days

21 MEarth Arizona 8 40cm telescopes Apogee U42 detectors (2kx2k) 25x25 arcminutes 0.76"/pixel 1 Planets detected GJ1214b (2009) MV: 14.7 Depth: 1.6% Periods: 1.58 days

22 Kepler Space 1m mirror 42 detectors (2kx1k) 115 square degrees 13.7"/pixel 36 Planets detected (25+2+9) MV: Depth: 0.02% - 1.6% Periods: days

23 Qatar New Mexico Four 400mm Canon f/2.8 One 200mm Canon f/2.0 FLI detectors (4kx4k) 5.2x5.2 degrees per CCD 4.6"/pixel 2 Planets detected MV: Depth: 2% - 3.7% Periods: days

24 Kepler & Qatar MEarth CoRoT XO, HATNet & SuperWASP TrES HD80606 OGLE STARE 185 transiting planets known, 695 planets in total

25 Transitsuche mit BEST II -- Feld 19 Thomas Fruth

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27 BEST2 F19_ Transittiefe 4,7% Transitdauer 4,5h Periode 4,887d Einzelne Nächte Folie 27

28 Transitkandidaten in F19 Folie 28

29 F20 Folie 29

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31 ASTEP cm Newton telescope 2kx2k Andor CCD 1 square degree

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35 Concordia [France Italia] S E 3233 m Concordia 1

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60 Transits from ground and space (examples) HD209458b (V: 7.65 mag) 10cm aperture telescope from ground Hubble Space Telescope Charbonneau et al detected by rv HD precision: 6x10-5 Brown et al CoRoT-2b (V: mag) 27cm aperture telescope in space 20cm aperture telescope at OHP detection Rauer et al archive Alonso et al. 2009

61 Detection range of transit surveys GJ1214b GJ436b Groundbased surveys Kepler 19b CoRoT 7b Kepler 11 b-g Kepler 9d Kepler 10b Kepler 4b Space surveys

62 Transiting planets: HAT:red, WASP: turquoise, CoRoT: green, Kepler: yellow