Photometry and Spectroscopy of Exoplanetary Atmospheres

Joseph HarringtonUniversity of Central Florida

Credit: N

ASA

/ JPL-C

altech / R. H

urt (SSC-C

altech)

Happy Birthdays, Sara (7/20) and Jay (7/19, age 6)!

UCF Planetary Sciences University of Central Florida – ORLANDO! 6th-largest US undergraduate univ., 50,100, growing PhD in Physics, Planetary Sciences Track Planetary Sciences Professors: (Search soon!)

Humberto Campins (comets)Daniel Britt (surfaces)Yanga Fernandez (comets)Joseph Harrington (exoplanets & atmospheres)Joshua Colwell (rings, ice, dust)Robert Peale (high-T molecular spectroscopy)Eduardo Martin (brown dwarfs & exoplanets)

Self-funded, soft-money: (Interested? Talk to jh!)Csaba Palotai (atmospheres)

Every planet is different – unlike stars! Big compositional differences, no dominant process Chaos reigns in orbits, meteorology, geophysics There will never be an H-R diagram for planets! In new situations, “good” models often fail

Assumptions no longer holdE.g., Over half the weather models can't do Venus's 4-day winds

Lessons of Planetary Science

Models vastly underconstrained All measured exoplanets far outside SS phase space

Exoplanetary Science

Explore exotic conditions for first timePulsar planetsRadical forcing (Hot Jupiters and Neptunes)Fe, enstatite clouds and rainTriaxial atmospheric geometryAtmospheric chemical latent heat cyclesDiamond/ocean planets, interior cooling problemsOrbital dynamics, habitability, formation...

Eliminate large areas of modeling phase space

Modelers permitted (funded) to:

Secondary Eclipses

Secondary Eclipses

First Direct Detection IDeming, Seager, Richardson, Harrington (2005, Nature)

HD 209458 b, Spitzer MIPS, 24 µm

1.5 h pre-eclipse, 3 h eclipse, 1.5 h post-eclipse

F24 m

= 55 10 Jy (10-26 W/m2/Hz)

FP/F

*= 0.0026 ± 0.00046

TB,24 m

= 1130 150 K

tSE

= t=0 + P/2 7 min

Significant orbital eccentricity very unlikely Inflated radius not likely due to tidal heating

Data

Deming et al. (2005b)

First Direct Detection II!Charbonneau et al. (2005, ApJ) submitted TrES-1 the same day!

Spitzer IRAC, 4.5 and 8 µm simultaneously

FP/F

*: 4.5 µm: 0.00066 ± 0.00013, 8 µm: 0.00225 ± 0.00036

Tb = 1060 ± 50 K

A = 0.31 ± 0.14

e = 0

Credit: N

ASA

/ JPL-C

altech / R. H

urt (SSC-C

altech)

S/N Champ: HD 189733 bK1-K2 star (small, cool), close (19.3 pc), V = 7.67

Rp = 1.26 R

Jup (bigish for a hot Jupiter)

Many times higher S/N than HD 209458 b

Dem

ing et al. (2006, ApJ 644, 560)

Measuring AtmospheresA planet's spectrum tells its story. Take Mars:

Broadband PhotometryKnutson et al. (2008, ApJ)

HD 209458b

Spitzer 3.6, 4.5, 5.7, 8

In eclipse

Day-side emission

Inversion

H2O evidence

Broadband PhotometryHD 189733b (Charbonneau et al.), no inversion

XO-1b (Machalek et al.)

A few planets are nice, but...

... we need enough to do statistics

This means looking at lower S/N

Spitzer ToO ProgramCollaborate with all willing discovery teams

Observe all planets w/ good Spitzer S/N

60 hr/year Cycles 3-5, 200 hr Warm Spitzer Cycle 6

Fill in plot of Tb vs.

T

eq

WASP 1,2,3,8,12,...; HAT 1,2,7; GJ 436b; CoRot 2, others

Legacy: Lightcurves derived from optimal pipeline

8-m Eclipses

GJ 436b

GJ 436b

Pixel-Phase Effect

Direct Measurementsafter H

arrington et al. (2007)

Phase Curvesafter H

arrington et al. (2006, Science)

Ups And b w/ Spitzer MIPS

Non-transiting planet

5 epochs around orbit

Big variation!

Radiation beats advection

Phase Curves

Knutson et al. (2007, Nature)

HD 189733b

IRAC 8-μm

Small variation

Temperature more homogenized

24-μm MIPS

Also GJ 436b, HD 149026b

Phase Curves

Laughlin et al. (2009, Nature)

HD 80606b

IRAC 8-μm

High e!

828 F* vari

Pseudosynch. rotation

Secondary!

4+-hr rad. time constant

Spectroscopy: Thermal +?Spitzer IRS, eclipse

HD 209458b: Richardson et al. (2007, Nature)

Continuum seen

Intriguing peaks

HD 189733b: Grillmair et al. (2007, ApJ)

Continuum seen

No peaks

Blame the Dark StuffSome planets have an absorbing material (TiO/VO)?

Absorbs ~all incoming light

Makes inversion/stratosphere

Emits strongly in near-mid IR, forms photosphere

rad

<< advect

: Instantaneous reradiation

Implies a colder back side – strong dynamical forcing

Other planets have more uniform T

T isn't the only factor in forming absorber

Variability on HD 149026b? Mira-like process for forming/destroying TiO? What energy input varies?

Combined-Light MissionEPOXI, SOFIA, warm Spitzer, CoRoT, Kepler, JWST, MOST, ground-based,: none optimized for exoplanet characterization

Room for a dedicated probe-scale mission

1-2 m, closed-cycle cooling, hides behind solar panel

Near-mid-IR point-source spectrophotometer

Good on-board calibration sources, 100-day stability

Much better/more appropriate measurements possible

UCF Winter School 2010!Exoplanets for Planetary Scientists

6-8 January 2010 (Wed – Fri)

UCF Campus, Orlando, Florida, USAhttp://planets.ucf.edu/winterschool2010

Advanced-grad-level “school” talks

Apply planetary theory to exoplanet cases

Nuts-and-bolts exoplanet observing

Oral and poster sessions with latest exoplanet results

Showcase results to planetary science community

Great place to pick up planetary collaborators!

Jupiter Impact Last Night Impact discovered 2009-07-19 before 13:30 UTC Discovered by amateur Anthony Wesley, Australia No impact 8 hours earlier Morphology very like SL9 http://jupiter.samba.org/ jupiter-impact.html 15-year anniversary of SL9

Jupiter Impact Last Night Glenn Orton (JPL) was observing Jupiter at IRTF Confirms high-altitude material in methane images

Jupiter Impact Last Night Weak methane-band image (889 nm) from Portugal Confirms high-altitude material