Ge/Ay133 What (exo)-planetary science can be done with transits and microlensing?

A Jupiter transit across the Sun is ~1%: Curvature?

Limb Darkening and Transit Profiles: Probes composition of atmosphere at day-night terminator Can search for clouds, hazes, condensates HST STIS transits of HD b from nm (Knutson et al. 2007a) Atmosphere Star Planet

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/

Transits and the Rossiter-McLaughlin effect (1924): Winn, J.N. et al. 2005, ApJ, 631, 1215

Photometry can be straightforward: Amateur observations of HD 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 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, Mpixel camera, 115 deg 2 FOV, 4’’ pixels

But ground-based work is making strides! HD HST At this level of performance (0.47 milli-mag) the transits of hot Neptunes are detectable & transit timing can put stringent limits on perturbing planets into the Earth mass range. Brown, T.M. et al. 2001, ApJ, 552, 699

Secondary eclipses can also put limits on the visible albedo. The MOST satellite finds A(HD209458b)<0.25 (1  ) (Jupiter=0.5, nm). Why so dark? Rowe, J.F.. et al. 2006, ApJ, 646, 1241

Transit photometry from space: Kepler

A comparison of transiting planet systems: As we’ll see, size is not a strong function of mass, so very accurate measurements are needed!

T = 1060 ± 50 K A = 0.31 ± 0.14 Secondary ecplises in the IR with Spitzer, see photons from the hot Jupiters! Charbonneau, D. et al. 2005, ApJ, 626, 523

T = 1060 ± 50 K A = 0.31 ± 0.14 Charbonneau, D. et al. 2005, ApJ, 626, 523 Rapid Pace of Spitzer Transit Results: HD b Mapping the temperature variation of a hot Jupiter… T(max)~1200 K, T(min)~970 K Hot spot ~30 ± 10° from the sub- stellar point Bond albedo~0.30 Must be reasonably efficient circulation from day to night side.

Other routes to Earth-like planets?

Microlensing example:

Are there Earth-like planets beyond the snow-line?

Rapid Progress: Transiting Planets, 1 May 2007

One year later (2008): 43 Systems And Counting Ice/Rock Planets

HD

Other Correlations: Why would the mass/gravity of a close-in planet be tied to the period? May be some tie to the mass of the star… B. Hansen & T. Barman 2007, ApJ, 671, 61

Other Correlations II: For a given T eq (not strictly distance since the spectral type varies…), two classes of planets versus Safronov number? B. Hansen & T. Barman 2007, ApJ, 671, 61

Seems also to be tied to the mass of the planets: Selection bias or poor stellar radii? X Redistribution of energy? More next time… Evaporation? X (if “hot start”) Tidal heating? Planetesimals & migration (tie to Safronov #)? Need composition(s)! B. Hansen & T. Barman 2007, ApJ, 671, 61