Ge/Ay133
What can transit observations tell us about (exo)-planetary science?
Sometimes the absence of signal is interesting:
No transits in 47 Tuc, `expectation’=30-40 (34,000 stars)
Gilliland, R.L. et al. 2000, ApJ, 545, L47
Transits, approach #1:
Search for transits in systems known to have planets at the doppler crossings.
Sato, B. et al. 2005, ApJ, astro-ph/0507009
Photometry is fairly straightforward: Amateur observations of HD 209458 b
Bruce L. Gary, Santa Barbara, CA
Arto Oksanen
SBIG cameras, Meade telescopes, V filters
Transits, approach #2:
Search for transits in many stars using a suite of low cost robotic telescopes.
TrES-1
Alonso, R. et al. 2004, ApJ, 613, L153
Photometry from space can be extremely good:
HD 209458 - HST
The KEPLER mission is dedicated to photometry and can search for earth mass planets in the so- called habitable zone.
Brown, T.M. et al. 2001, ApJ, 552, 699
www.kepler.arc.nasa.gov
Transits and the Rossiter-McLaughlin effect (1924):
Winn, J.N. et al. 2005, ApJ, 631, 1215
A comparison of transiting planet systems:
Remember, size is not a strong function of mass, so very accurate measurements are needed!
HD 149026
T = 1060 ± 50 KA = 0.31 ± 0.14
Secondaryecplises in the IR with Spitzer, see photons from the hot Jupiters!
Charbonneau, D. et al. 2005, ApJ, 626, 523
Hot Jupiter atmospheres?
M L T
In the optical/near-IR, the spectra of M → T dwarfs (similar temp. as the hot Jupiters) show strong alkali metal lines:
First detection ofan extrasolar planetatmosphere:
Look for the transit depth in filters on and off the Na D-line with HST.
Charbonneau, D. et al. 2001, ApJ, 568, 377
Atmospheres Part II: Most atoms have their so called resonance lines in the UV. The H I depth is VERY large. EXOSPHERE?
Vidal-Madjar, A. et al. 2004, ApJ, 604, L69
Secondary eclipses canalso put limits on the visiblealbedo. The MOSTsatellite findsA(HD209458b)<0.25 (1) (Jupiter=0.5, 300-700 nm). Why so dark?
Rowe, J.F.. et al. 2006, ApJ, 646, 1241
What about chemistry? Need IR observations:
GL 229B (BD)
T dwarf IR opacities dominated by CH4, H2O.
Oppenheimer, B. et al. 1998, ApJ, 502, 932
Spitzer phtometry and IR atmospheric models:
Charbonneau, D. et al. 2005, ApJ, 626, 523
Ground? Challenge is the Earth’s atmosphere!
Limits only just beginning to reach sufficient sensitivity.
CO Search
Terrestrial CH4
Deming, D. et al. 2005, ApJ, 622, 1149
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