Transiting Extrasolar Planets discovered by the

XO ProjectMuseum and Planetarium Museum and Planetarium

BriefingBriefingPeter R. McCulloughPeter R. McCullough

May 1, 2008May 1, 2008

Copyright Notice

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XO data distilledThe special star’s …

• Position (RA, DEC)

• Time

• Depth

• Width

• Period

Approximately 10 bytes of information!

XO data rateEach clear night, XO gathers…

• as much data as HST• 1 billion pixels• 1000 images• 100 epochs of 10000 stars suitable for transit detection

XO observes each target for months.

XO data rateEach clear night, XO gathers…

•1 billion pixels• 2 Gbytes• the equivalent of 1,000,000 printed ASCII pages

After operating for 4 years, XO has accumulated the equivalent of a forest of 4000 stacks of paper like the one under Bill Gates.

If printed, XO data would cost, at $0.01/page, $10,000 per night.

“ “Traditional” RV surveysTraditional” RV surveys Marcy et al (HD 209458)Marcy et al (HD 209458) Hot-Neptunes (GJ436)Hot-Neptunes (GJ436)

Photometric surveys:Photometric surveys: HAT: HAT: 2.5 bright (V=8-12)2.5 bright (V=8-12) XO: XO: 3 bright (V=10-11)3 bright (V=10-11) TrES: TrES: 2.5 bright (V=11.4, V=11.8) 2.5 bright (V=11.4, V=11.8) WASP:WASP: 2 bright (V=11.8, V=12.0)2 bright (V=11.8, V=12.0) OGLE: OGLE: 5 faint (V ~15) (10b, 56b, 111b, 5 faint (V ~15) (10b, 56b, 111b,

113b, 132b)113b, 132b) Others Others 2 faint (Lupus, SWEEPS)2 faint (Lupus, SWEEPS) OthersOthers (in process)(in process)

Metalicity-filtered RV surveysMetalicity-filtered RV surveys N2K (HD 149026, V=8)N2K (HD 149026, V=8) OHP (HD 189733, V=8)OHP (HD 189733, V=8)

Summary of Transiting Extrasolar Planets

1 year ago, May 2007: N = 17

“ “Traditional” RV surveysTraditional” RV surveys Marcy et al (HD 209458)Marcy et al (HD 209458) Hot-Neptunes (GJ436)Hot-Neptunes (GJ436) TransitSearch.org (HD 17156)TransitSearch.org (HD 17156)

Photometric surveys:Photometric surveys: HAT: HAT: 7 bright (V=8-12)7 bright (V=8-12) XO: XO: 3 bright (V=10-12), (more, May 20)3 bright (V=10-12), (more, May 20) TrES: TrES: 4 bright (V=11-12) 4 bright (V=11-12) WASP:WASP: 5[+10] bright (V<13)5[+10] bright (V<13) OGLE: OGLE: 7 faint (V ~15)7 faint (V ~15) Corot:Corot: 2 faint (V=12.6, V=13.6)2 faint (V=12.6, V=13.6) Others: Others: 3 very faint (Lupus, SWEEPS)3 very faint (Lupus, SWEEPS) Others Others (in process)(in process)

Metalicity-filtered RV surveysMetalicity-filtered RV surveys N2K (HD 149026, V=8)N2K (HD 149026, V=8) OHP (HD 189733, V=8)OHP (HD 189733, V=8)

Summary of Transiting Extrasolar Planets

May 1, 2008: N=46

Absorption Spectra of Planetary AtmosphereAbsorption Spectra of Planetary Atmosphere Precise photometry and timing of transitsPrecise photometry and timing of transits

Oblateness (rotation rate) of planetOblateness (rotation rate) of planet Rings, Satellites of planetRings, Satellites of planet Perturbations from TP: Perturbations from TP: TOA) ~ many secondsTOA) ~ many seconds Limb darkening and star spotsLimb darkening and star spots

Secondary EclipseSecondary Eclipse Temperature, Temperature, f/f ~ ( Tf/f ~ ( Tpp/T/Tss ) ( R ) ( Rpp/R/Rss ) )22 ~ 0.4% in IR ~ 0.4% in IR Map of IR brightness of planet’s “surface”Map of IR brightness of planet’s “surface” Eccentricity better than RV methodEccentricity better than RV method Albedo, Albedo, f/f ~ 0.02% x optical albedof/f ~ 0.02% x optical albedo

Key: Key: donedone and feasible but not demonstrated yet and feasible but not demonstrated yet

XO targets Bright Stars that allow …

Extrasolar Visions Inc.

Haleakala’s typical weather

XO Cameras and Robotic mount

Unique aspects: 1) Two cameras (pilot & copilot)2) 0.4-0.7 micron bandpass3) Powered drift scanning (like SDSS)

XO-N telescope parade:

XO Extended Team

Paul HowellPaul Howell Franco MalliaFranco Mallia Gianluca MasiGianluca Masi Tonny VanmunsterTonny Vanmunster

RBBG

XO

TVCF PH

MFEG

Ron BissingerRon Bissinger Mike FleenorMike Fleenor Cindy FooteCindy Foote Enrique GarciaEnrique Garcia Bruce GaryBruce Gary

FMGM

XO’s Extended Team: E.T. = Advanced Amateur AstronomersE.T. = Advanced Amateur Astronomers

(Olympic athletes are amateurs too…)(Olympic athletes are amateurs too…) Global longitude coverageGlobal longitude coverage More and Better photometry (next slide)More and Better photometry (next slide) ““A spectrum saved is a spectrum earned.”A spectrum saved is a spectrum earned.”

LocationLocation 16h +28deg16h +28deg Corona BorealisCorona Borealis

StarStar V = 11.2 magV = 11.2 mag Sp. Type = G1 VSp. Type = G1 V D = 200 pcD = 200 pc

PlanetPlanet Period = 3.94 daysPeriod = 3.94 days Mass = 0.9 M_JupiterMass = 0.9 M_Jupiter Radius = 1.3 R_JupiterRadius = 1.3 R_Jupiter

Additional planets in system? Not yet…Additional planets in system? Not yet…

XO Planet 1 a.k.a. XO-1b

AAS Abstract (May 2007)Title: XO-2b: A Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary Authors: Burke, Christopher J. (STScI), McCullough, P. R. (STScI), Valenti, Jeff A.

(STScI), Summers, F. J. (STScI), Stys, J. E. (STScI), Johns-Krull, C. M (Rice Univ.), Janes, K. A. (Boston Univ.), Heasley, J. N. (Univ. Hawaii), Bissinger, R. (Racoon Run Obs.), Fleenor, M. (Volunteer Obs.), Foote, C. N. (Vermillion Cliffs Obs.), Garcia-Melendo, E. (Duran Obs.), Gary, Bruce L. (Hereford AZ Obs.), Howell, P. J. (Boston Univ.), Mallia, F. (Campo Catino Obs.), Masi, G. (Bellatrix Obs.), Vanmunster, T. (CBA Obs.)

Abstract: XO-2b, the second transiting extrasolar planet from the XO Project (McCullough et al. 2005), is approximately Jupiter-size and 0.6 Jupiter-mass with an orbital period of 2.6 days. The stellar host, XO-2, is a V=11, early K dwarf which is metal rich, [Fe/H]=+0.44. XO-2 has a high proper motion and has a common proper motion stellar companion. The two stars are nearly identical twins, with very similar spectra and apparent magnitudes. The global network of amateur and professional astronomers organized by the XO project confirmed the XO-2b transit light curve two days after being notified that it was a high-priority candidate, and radial velocities confirmed its planetary mass eight days after that.

AAS Abstract (May 2007)Title: The Unusual Transiting Extra-Solar Planet Orbiting XO-3

Christopher M. Johns-Krull1, P. M. McCullough2, C. J. Burke2, J. A. Valenti2, K. A. Janes3, J. N. Heasley4, R. Bissinger5, M. Fleenor6, C. N. Foote7, E. Garcia-Melendo8, B. L. Gary9, P. J. Howell3, F. Mallia10, G. Masi11, L. A. Prato12, T. Vanmunster13 1Rice Univ., 2STScI, 3Boston Univ., 4Univ. Hawaii, 5Racoon Run Obs., 6Volunteer Obs., 7Vermillion Cliffs Obs., 8Duran Obs., 9Hereford AZ Obs., 10Campo Catino Obs., 11Bellatrix Obs., 12Lowell Obs., 13CBA Obs..

Abstract: We report the discovery of a massive planet (≈12 MJUP) in an eccentric orbit (e ≈ 0.2) around the F6 star XO-3. This planet transits the 10th magnitude star every 3.19 days. This system is unusual for a number of reasons. XO-3b is one of the most massive planets discovered around any star for which the orbital period is less than 10 days. The mass is near the deuterium burning limit of 13 MJUP which is a proposed boundary between planets and brown dwarfs. Burrows et al. (2001) propose that formation in a disk or formation in the interstellar medium in a manner similar to stars is a more logical way to differentiate planets and brown dwarfs. Our current observations are not adequate to address this distinction. XO-3b is also unusual in that its eccentricity is large given its relatively short orbital period. Finally, the star XO-3 is somewhat metal poor, with [Fe/H] ≈ -0.25. We will present our observations leading to this discovery and discuss the implications of this system for models of planet formation.

Transiting hot Jupiters

Planet-sized brown-dwarf edge

M dwarfs

Fred

eric

Pon

t 200

5

Radius versus Mass --- expanded scales

Rare here

XO Constellation, Phase 1 = 3 units

Operational 2003-2007Haleakala

Operational 2008-Haleakala

+

1 unit ($50k) = 2 lenses, 2 CCDs, 1 mount, 3 computers

XO Extended Team

RBBG

XO

TVCF PH

MFEG FM

GM

Further Reading

Websites:Websites: XO Project: http://www-int.stsci.edu/~pmcc/xo/XO Project: http://www-int.stsci.edu/~pmcc/xo/ Pont’s site: http://www.inscience.ch/transits/Pont’s site: http://www.inscience.ch/transits/ Exoplanet Encyclopedia: http://exoplanet.eu/Exoplanet Encyclopedia: http://exoplanet.eu/

XO PublicationsXO Publications XO-3 arXiv:0712.4283 XO-3 arXiv:0712.4283 XO-2 arXiv:0705.0003 XO-2 arXiv:0705.0003 XO-1 arXiv:astro-ph/0605414 XO-1 arXiv:astro-ph/0605414 Search Technique: Search Technique:

arXiv:astro-ph/0505560 arXiv:astro-ph/0505560 arXiv:astro-ph/0703331 arXiv:astro-ph/0703331

Articles about XO:Articles about XO: Sky & Telescope Sep 2006 issueSky & Telescope Sep 2006 issue (Knutson popular article on E.T.)(Knutson popular article on E.T.)