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