ImprovingImproving TransitTransit PredictionsPredictions ofof KnownKnown ExoplanetsExoplanets withwith TERMSTERMS Stephen R. KaneStephen R. Kane11, David Ciardi, David Ciardi11, Diana Dragomir, Diana Dragomir11, Debra Fischer, Debra Fischer22, Greg Henry, Greg Henry33, Andrew Howard, Andrew Howard44, Eric Jensen, Eric Jensen55, , Greg LaughlinGreg Laughlin66, Suvrath Mahadevan, Suvrath Mahadevan77, Genady Pilyavsky, Genady Pilyavsky77, Kaspar von Braun, Kaspar von Braun11, Xuesong Wang, Xuesong Wang77, Jason Wright, Jason Wright77 1 NASA Exoplanet Science Institute, Caltech, MS 10022, 770 South Wilson Avenue, Pasadena, CA, 91125, USA 2 Department of Astronomy, Yale University, New Haven, CT, 06520, USA 3 Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd, Nashville, TN, 37209, USA 4 Department of Astronomy, University of California, Berkeley, CA, 94720, USA 5 Department of Physics & Astronomy, 500 College Ave, Swarthmore College, Swarthmore, PA, 19081, USA 6 UCO/Lick Observatory, University of California, Santa Cruz, CA, 95064, USA 7 Department of Astronomy & Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA, 16802, USA
MonitoringMonitoring known known radial radial velocity velocity planets planets at at TERMS Telescopes predictedpredicted transit transit times, times, particularly particularly those those TERMS Telescopes planetsplanets in in relatively relatively eccentric eccentric orbits, orbits, DueDue to to the the wide wide range range of of stars stars monitored, monitored, presentspresents an an avenue avenue through through which which to to bothboth in in sky sky location location and and brightness, brightness, TERMS TERMS exploreexplore the the mass-radius mass-radius relationship relationship of of collaboratescollaborates withwith aa varietyvariety ofof existingexisting groupsgroups exoplanetsexoplanets around around bright bright host host stars. stars. Here Here toto take take advantage advantage of of transit transit window window wewe describe describe techniques techniques for for refining refining opportunities.opportunities. TelescopesTelescopes usedused include:include: ephemeridesephemerides and and performing performing follow-up follow-up observations.observations. These These methods methods are are used used by by ➢ CTIOCTIO 0.9m0.9m thethe Transit Transit Ephemeris Ephemeris Refinement Refinement and and ➢ CTIOCTIO 1.0m1.0m (pictured(pictured -- top)top) MonitoringMonitoring SurveySurvey (TERMS).(TERMS). ➢ LCOLCO 1.0m1.0m ➢ Keck/HIRESKeck/HIRES (pictured(pictured -- bottom)bottom) ➢ APTAPT 0.8m0.8m (Fairborn(Fairborn Observatory)Observatory) ➢ UCO/LickUCO/Lick 3.0m3.0m ➢ Hobby-EberlyHobby-Eberly TelescopeTelescope TransitTransit ProbabilitiesProbabilities ➢ PeterPeter vanvan dede KampKamp ObservatoryObservatory 0.6m0.6m HereHere wewe brieflybriefly showshow thethe combinedcombined effecteffect ofof thethe eccentricityeccentricity andand thethe argumentargument ofof periastronperiastron onon thethe primaryprimary transittransit probability.probability. ThisThis isis describeddescribed inin detaildetail byby KaneKane && vonvon BraunBraun (2008)(2008) andand KaneKane && vonvon BraunBraun (2009).(2009). MonitoringMonitoring ofof HDHD 156846b156846b
Transit Window
AnAn exampleexample TERMSTERMS targettarget isis thethe hosthost starstar HDHD 156846156846 (Kane(Kane etet al.al. 2011)2011) whosewhose TheThe above-leftabove-left figurefigure showsshows thethe effecteffect uponupon thethe primaryprimary transittransit probabilityprobability asas planetplanet isis inin aa 359359 dayday period,period, highlyhighly eccentriceccentric orbitorbit (shown(shown above).above). NewNew KeckKeck wewe rotaterotate thethe semi-majorsemi-major axisaxis aroundaround thethe starstar forfor eccentricitieseccentricities ofof 0.0,0.0, 0.3,0.3, datadata combinedcombined withwith thethe CORALIECORALIE discoverydiscovery datadata (Tamuz(Tamuz etet al.al. 2008)2008) producedproduced andand 0.6.0.6. TheThe angle angle θθ inin thethe above-rightabove-right figurefigure correspondscorresponds toto thethe rangerange ofof ωω anan uncertaintyuncertainty inin thethe transittransit mid-pointmid-point ofof onlyonly 2020 minutes!minutes! forfor whichwhich thethe ellipticalelliptical probabilityprobability isis lessless thanthan forfor aa circularcircular orbitorbit ((θθ == 105105°° inin NextNext predictedpredicted transittransit mid-point:mid-point: thisthis case). case). The The eccentricity eccentricity of of long-period long-period planets planets can can raise raise their their likelihood likelihood of of transitingtransiting toto aa statisticallystatistically viableviable numbernumber forfor detection.detection. JDJD 2455797.592455797.59 2011/08/242011/08/24 02:1202:12 UTUT
NoNo TransitTransit forfor HDHD 114762b114762b RefiningRefining thethe EphemeridesEphemerides TheThe planetplanet HDHD 114762b114762b waswas TheThe transittransit ephemerisephemeris forfor aa particularparticular planetplanet cancan oftenoften bebe significantlysignificantly improvedimproved recentlyrecently analysed analysed using using withwith the the addition addition of of a a handful handful of of high-precision high-precision radial radial velocity velocity data. data. For For TERMSTERMS datadata whichwhich createscreates aa example,example, the the planet planet orbiting orbiting the the star star HD HD 231701, 231701, discovered discovered by by Fischer Fischer et et al al RVRV baseline baseline of of 19 19 years years (2007),(2007), hashas aa currentcurrent transittransit windowwindow ofof ~82~82 daysdays basedbased uponupon thethe discoverydiscovery data.data. (Lick)(Lick) and and a a photometric photometric TheThe addition addition of of four four baselinebaseline of of 23 23 years years (APT). (APT). subsequentsubsequent measurements measurements TheThe revised revised data data and and (as(as shown shown in in this this figure) figure) KeplerianKeplerian orbitalorbital solutionsolution areare wouldwould improve improve both both the the shownshown inin thisthis figure.figure. TheThe RVRV precisionprecision of of the the period period and and andand photometric photometric data data rule rule timetime ofof periastronperiastron passage,passage, outout additional additional companions companions in in resultingresulting in in a a reduction reduction of of thethe systemsystem andand alsoalso rulerule outout thethe transit transit window window to to 3.7 3.7 transitstransits >> 11 millimag.millimag. daysdays - - a a factor factor of of almost almost 25!25! Through Through selective selective observationsobservations at at optimal optimal times,times, we we produce produce viable viable ReferencesReferences targetstargets for for photometric photometric ➢ Fischer, D.A., et al., 2007, ApJ, 669, 1336 ➢ Kane, S.R., et al., 2009, PASP, 121, 1386 follow-up.follow-up. ➢ Kane, S.R., von Braun, K., 2008, ApJ, 689, 492 ➢ Kane, S.R., et al., 2011, ApJ, in press ➢ Kane, S.R., von Braun, K., 2009, PASP, 121, 1096 ➢ Tamuz et al., et al., 2008, A&A, 480, L33