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KEPLER'S TREASURE CHEST OF ECLIPSING BINARY STARS

KEPLER'S TREASURE CHEST OF ECLIPSING BINARY STARS

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KEPLER’S TREASURE CHESTOF ECLIPSING BINARY STARSSteven Bloemen – University of LeuvenESAC, 29 October 2012


3 main fields of study using Kepler data:Planets Asteroseismology Eclipsing binary starsOctober 2012:2321 (published) planet candidates77 confirmed planets


Kepler eclipsing binaries¨ Most precise photometric datasets ever(400-900nm)¨ Survey type mission: 150 000 targets¨ Eclipsing binaries (>2500), triples, …¨ Hundreds ofpulsators inbinaries¨ A few circumbinaryplanetsKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler EBs1273 (58%) detached EBs152 (7%) semi-detached EBsCatalogues:Prsa et al. 2011, Slawson et al. 2011,Kirk et al. 2012 (in prep)http://keplerEBs.villanova.eduKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler EBs1273 (58%) detached EBs152 (7%) semi-detached EBs469 (22%) overcontact EBsCatalogues:Prsa et al. 2011, Slawson et al. 2011,Kirk et al. 2012 (in prep)http://keplerEBs.villanova.eduKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler EBs1273 (58%) detached EBs152 (7%) semi-detached EBs469 (22%) overcontact EBs139 (6%) ellipsoidal144 (7%) uncertainCatalogues:Prsa et al. 2011, Slawson et al. 2011,Kirk et al. 2012 (in prep)http://keplerEBs.villanova.eduKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Heartbeat starsUnusual brightenings in eccentric binariesTidally induced pulsations


‘Heartbeat stars’KOI-54Nearly face-on binary, e=0.83, P=41.8dT 1 =8500K, T 2 =8800KThe Astrophysical Journal Supplement Series, 197:4(14pp),2011NovemberWelsh et al. 2011, ApJSSWelsh et al.Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


thorough asteroseismic analysis of δ Scuti stars is rarely achieved due to the large number of oscillatorymodes present in most of these objects. Although, with the continuation of work in this field, it isexpected that an increasing number of these intriguing objects will be solved in the foreseeable future.‘Heartbeat stars’1.4 Tidal InteractionsIn a binary system, if the components are in relatively close proximity to one another, the gravitationalKOI-54Nearly face-on binary, e=0.83, P=41.8dT 1 =8500K, T 2 =8800KWelsh et al. 2011, ApJSSforces between the two components can provoke tidal interactions; analogous to the lunar tides generatedon the Earth. Moreover, if the binary is eccentric as seen in Fig. 3, the tides generated become misalignedwith respect to their instantaneous equipotential shapes (Hut, 1980). This generates torque betweenthe two components which causes an exchange of angular momentum between the orbital and stellarrotations, and further causes the system’s energy to dissipate.Kepler’s Figuretreasure 3: An chest image of of EBs an– eccentric Steven Bloemen binary– orbit. ESAC– Due 29 October the eccentricity 2012 of the orbit, distance between thetwo stars, denoted by the radius vector, varies with time. Consequently, the gravitational forces acting on the


The Astrophysical Journal Supplement Series, 197:4(14pp),2011NovemberWelsh et al.‘Heartbeat stars’KOI-54Welsh et al. 2011, ApJSSFigure 4. Light curves showing individual brightening events with the observations plotted as red dots, the ELCsinus model fit in black, and the residuals (offset by+0.998 and scaled by a factor of five) in green. The lower right-hand panel shows the model only.Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012(A color version of this figure is available in the online journal.)


‘Heartbeat stars’KOI-54The Astrophysical Journal Supplement Series, 197:4(14pp),2011NovemberWelsh et al. 2011, ApJSSWelsh et al.1.0041.003e = 0.1, 0.3, 0.5, 0.6, 0.7, 0.81.0021.0011.0001.0141.0121.0101.0081.0061.0041.0021.000e = 0.80, 0.82, 0.84, 0.86, 0.880.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10orbital phaseFigure 6. Illustrative ELC model light curves showing the effect of eccentricity on the amplitude of the brightening at periastron. Eccentricity increases from thelower curve to the upper curve. The strong sensitivity of the brightening to eccentricity allows the eccentricity to be determined independently of the radial velocities.The lower panel shows a tighter range of eccentricities, and by inspection, one can see that a brightening amplitude of 0.7% requires an eccentricity near 0.84 for thisi = 5 ◦ example.(A color version of this figure is available in the online journal.)Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


The Astrophysical Journal Supplement Series, 197:4(14pp),2011NovemberTable 3Thirty Largest KOI-54 PulsationsID Frequency Frequency Amplitude f/f orbit Nearest(day −1 ) (µHz) (µmag) HarmonicF1 2.1529 24.917 297.7 90.00 90F2 2.1768 25.195 229.4 91.00 91F3 1.0525 12.182 97.2 44.00 44F4 0.9568 11.074 82.9 40.00 40F5 0.5363 6.207 82.9 22.42 ···F6 1.6405 18.988 49.3 68.58 ···F7 1.7222 19.933 30.2 72.00 72F8 1.5087 (Smeyers et 17.462 al. 1998, Willems 17.3 & Aerts 63.07 2002, 63F9 1.3773 Aerts 15.941& Harmanec 15.9 2004) 57.58 ···F10 0.6697 7.751 14.6 28.00 28F11 1.2678 14.673 13.6 53.00 53F12 1.1241 13.011 13.4 46.99 47F13 0.9329 10.798 12.5 39.00 39F14 1.4349 16.608 11.6 59.99 60F15 0.8851 10.244 11.5 37.00 37F16 Are 1.6983 both stars 19.656 pulsating? 11.4If not, 71.00 why not? 71F17 0.6183 7.156 11.1 25.85 ···…F18 1.8178 21.039 9.8 75.99 76F19 0.8574 9.924 9.3 35.84 ···F20 0.6458 7.475 9.1 27.00 27F21 1.0284 11.903 8.4 42.99 43F22 1.0765 12.460 8.3 45.01 45F23 1.5092 17.467 8.1 63.09 63F24 0.8610 9.965 6.9 35.99 36F25 1.4452 16.726 6.8 60.42 ···F26 1.2439 14.397 6.4 52.00 52F27 1.0078 11.664 6.3 42.13 ···F28 0.7894 9.137 5.9 33.00 33F29 0.6937 8.028 5.8 29.00 29F30 1.1483 13.290 5.7 48.00 48Only fourth system with tidally excited oscillationsOrbital freq. must be close to eigenfrequency of starWhy are 90 th and 91 st harmonics strongest modes?Why are adjacent harmonics not present at all?dependence of the amplitude of the brightenineccentricity as illustrated in Figure 6.Inthissetclosely matched to KOI-54, the only parametethe eccentricity. In particular, the lower panelcan estimate the eccentricity to ∼1% just fromif all other parameters were known. The stroneccentricity is simply a consequence of the brdue to tidal forces and irradiation that scale asof the stars cubed and squared, respectively, anof the stars at periastron is linear in the eccentrare assuming simple tidal distortion aligned aloing the center of masses; in the general asymtidal force is much more sensitive to the sepaF ∝ r −7 —see Hut 1981 for a discussion.)In addition to the eccentricity, the Kepler phoable to constrain the orbital inclination, even tno eclipses and no double-humped ellipsoidapresent. But in fact the ellipsoidal variations asuch a highly eccentric orbit the humps have spulsations in KOI-54Tidally inducedusual photometric quadrature phases, 0.25 and 0of periastron (defined here as phase 1.0), andmerged. The two humps are not equal in heigorbital inclination is not exactly zero and the orbnot aligned along our line of sight (the argumentnot ±90 ◦ ); thus the two phases of maximum vidistortion are not symmetric about periastron.inclination and argument of periastron determinof the irradiated hemispheres of the stars to oand this creates a small asymmetry and shiftthe brightening. For the geometry of KOI-54inclination, the more the peak would shift tophases, and the narrower the peak the more asymbecome (brighter post-peak than pre-peak). Su


B. radial Howell veorbitA 94035, (Fig-USA, susan.e.thompson@nasa.gov, 2 Bay Area5 , M. Still 6 , J. L. Christiansen 7 , and J. Rowe 8.gov, 3 SETI/NASA‘HeartbeatAmes, fergal.mullally@nasa.gov,stars’nasa.gov, systems,6 Bay Area Environmental Research Institute,hristiansen@nasa.gov,detection8 SETI/NASA Ames, jason-cillations.the phystemsanduence tbeat Stars: the A Class of Tidally Excited Eccentric BinariesThompson inary fits1 , T. Barclay 2 , F. Mullally 3 , M. Everett 4 , S. B. Howell 5 , M. Still 6 , J. L. Christiansen 7 , and J. Rowe 8he I Institute/NASA proper- Ames M/S 244-30, Moffett Field, CA 94035, USA, susan.e.thompson@nasa.gov, 2 Bay Areaonmental Research Institute, thomas.barclay@nasa.gov, 3 SETI/NASA Thompson Ames, fergal.mullally@nasa.gov,et al., 2012O, everett@noao.edu, 5 NASA Ames, steve.b.howell@nasa.gov, 6 Bay Area Environmental Research Institute,n.still@nasa.gov,7 SETI/NASA Ames, jessie.l.christiansen@nasa.gov,8 SETI/NASA Ames, jason-@gmail.comtroduction: We have Figure discovered 1. Example a class light of ecicbinary systems undergoing dynamic tidal dis-curves.ns and tidally induced pulsations in the KeplerEach has a uniquely shaped light curve that iscterized by periodic brightening or variability atscales of 4-20 days which is frequently accompabyshorter period oscillations (Figure 1). We canin the dominant features of the entire class withing tidal forces that occur in close, eccentric bisystems.In this case the large variety of lightshapes Kepler’s arises from treasure viewing chest of systems EBs – Steven at different Bloemen – ESAC– 29 October 2012s. A hypothesis that is confirmed with radial ve-


(were Kp stands for the Kepler band pass magnitude). The Kepler band pass, which is essentially awhite light broadband filter, includes the the g-r-i-z filter sequence consistent with the Sloan DigitalSky Survey.‘Heartbeat stars’KIC 4544587KIC 4544587 is in the constellation Lyra at a distance of approximately 1.7 kpc; otheridentifiers for this object can be found in Table 1. The primary component is an early A star that iswithin the δ Scuti instability strip and the secondary component is an early G star, which is likely to bea solar type oscillator, although no solar-like oscillations have been identified in our data. It is also likelythat the primary component is a metallic-lined, Am star, presuming that through tidal interactions theequatorial rotation rate is v equ < 120 km s −1 ,whichisslowenoughfordiffusion to occur (Abt, 2009).K. Hambleton 2011, MSc. ThesisP = 2.2di = 88dege = 0.28Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Figure 7: The total observed Kepler, shortcadencelightcurvefromQuarter3.2.


of binary systems, they are dependent on orbital phase (Moreno et al., 2011). This suggests that if theorbital frequency, or integer multiple of the orbital frequency, is close enough to a natural mode of abinary star, and the gravitational interaction between the binary components is strong enough; it is‘Heartbeat stars’possible for resonant modes to be excited.During periastron passage the components of KIC 4544587, according to the models generated, haveasurface-to-surfaceseparationof5R ⊙ (∼8R ⊙ from centre-to-centre). Furthermore, the eccentricity ofthe system is e =0.28375± 0.000005 (where the value is taken from the Quarter 3.2 model and the erroris the formal error). The combination of these two aspects of KIC 4544587, alongside the δ Scuti natureKIC 4544587K. Hambleton 2011, MSc. Thesisof the primary component, make KIC 4544587 a good candidate for tidal resonance.Figure 22: AcomparisonbetweentheQuarter3.2 data with all the frequencies removed (red), and with all thefrequencies except the orbital harmonics removed (green). The residual features in the green light curve appearto be pulsations, suggesting that the harmonic frequencies are indeed intrinsic to KIC 4544587, and not generatedKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Tidally induced pulsations in triple systemPair of red dwarfs with P orb =0.9d in 45-day orbit around a red giantREPORt:d-pd.oo-de-ye-ehKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Derekas et al. 2011


is expressedJulian date.-upsoftwoima and twoa of the 45.5-The dashedes mark thethe secondthe0.9-dayVariability during secondary eclipses (when dwarfs are eclipsed by giant),at the orbital period of the dwarfsectively. Thes in (A) coretelescopend of eachTidally induced pulsations in triple systemKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Derekas et al. 2011


Close binary starsDoppler beaming, ellipsoidal, reflectionLight travel time effects (eclipses, pulsations)


KPD 1946+4340¨ sdB+WD binary, P orb = 0.4 d, eclipsing¨ Q1 short cadence Kepler data [KIC 7975824]:58s sampling, 33d time spanKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


KPD1946+4340: WD+sdBEclipses + reflectionKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Bloemen et al. 2011


KPD1946+4340: WD+sdBEclipses + reflection + ellipsoidalKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Bloemen et al. 2011


KPD1946+4340: WD+sdBEclipses + reflection + ellipsoidal + lensingKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Bloemen et al. 2011


KPD1946+4340: WD+sdBEclipses + reflection + ellipsoidal + lensing + beamingKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Bloemen et al. 2011


Doppler beaming¨servations of the beaming binary c KPD 1946+4340 54).etnedwas(1)pesedTEin-0K,2.¨velocity tometrically of the primarydetermined of KOI-74 radial is yet to velocity. be confirmed itational lenspectroscopically.ForForradialKPDvelocities1946+4340,thatradialarevelocitiesmuch smallerarethanaroundthetheavailable which allows the first spectroscopic check of a photometricallydetermined radial velocity. λ is related to the emittedappear smaspeed of light, the observed flux Ffication e eForfluxradialF 0,λvelocitiesasthat are much smaller than the that is visibspeed of light, the observed ( flux F is related to the emitted the lensingFlux flux increase/decrease F 0,F λ = F 0,λ 1 −due B v )rto , velocity of stars in orbit part of (2) the⇣F = F 0, 1 v ⌘in compactrwith ⇣ B the beaming , factor B =5+dlnF(2)cλ /dlnλ (Loeb Gould (199 &F& GillilandExpected⇥ = F 0,⇥Gaudi 1 2003). B v ⌘rThe , beaming factor thus depends on (2) the spectrumin beaming Kepler of thecLCs factor star and B =5+dlnF the wavelength /d ln ⇥ of(Loeb the observations. & crolensing For ewith B the[LOEB Gaudi & GAUDI 2003). 2003; The beaming ZUCKER ET factor AL. 2007: thus ‘beaming dependsbinaries’]on the spectrumof the star and the wavelength of the observations. For lensing e eplanetary swith B the broadband beaming factor Kepler B photometry, =5+dlnF ⇥ we /duse ln ⇤ a(Loeb photon&weightedGaudi 2003). bandpass-integrated The beaming factor beaming thus factor depends on the spectrum[VANKERKWIJK ET AL. 2010]the broadband Kepler photometry, we use a photon weighted sequence stbandpass-integrated of the star∫ andbeaming the wavelength factor of the observations. For planet, whiKeplerthe broadbandbandpass R 〈B〉 = Kepler ɛλ λF λ Bdλ∫photon photometry,weighted factorwe usefrom a photonatmosphereweightedmodeltherefore (3) ea⇥F Bd⇥(dependsbandpass-integrated ɛλ λF⌅B⇧ =on assumedbeamingmetallicity λ dλ factoretc.!):(3) dwarf. In thR ⇥F d⇥two componin ⇥⇥ which ⇤F ⇥ Bd⇤ ɛ λ is the response function of the Kepler bandpass.⌅B⇧ reduced depin which = RisWithout the response =1.30taking function ±reddening0.03 of the Kepler into bandpass. account, the(3)⇥⇥ ⇤F ⇥ d⇤ beaming itational lenWithout factortaking is found reddening to be into 〈B〉 account, =1.247 ± the0.008. beaming The uncertainty(components: factor is found aberration to ⌅B⇧ +2, photon =1.247 arrival ± 0.008. rate The +1, Doppler uncertainty shift -1.7) equivalent tin whichis⇥ ⇥ estimated is the response from the function uncertainties of the Kepler on Tbandpass.efflogradius. g. This Theis estimated We from the uncertainties on T e and log g. Thistime, determined the effect the beaming of reddening factorwas fromaccounted a series offor fully byour changingthe spectral LTEresponse models (Heber accordingly et al. 2000, instead see of alsolight cumetal time, the line-blanketed e ect of reddening was accounted for by chang-reddening¨ Detected in long cadence Kepler light curve of KOI 74¨Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Table 2. Properties of KPD 1946+4340. The orbital period andthe effective temperature of the sdB were derived from spectroscopy.The other parameters are obtained by modelling theKepler light curve. The uncertainties on these values are determinedby MCMC analysis, using the prior constraint that thewhite dwarf mass-radius relation has to match the Eggleton relationto within 5% RMS.MCMC results for KPD1946Primary (sdB)sdB parameters Photometry SpectroscopyK 1 (km/s) 168 ± 4 164.0 ± 1.9log(g) 5.452 ± 0.006 5.43 ± 0.04v sin(i) (km/s) 26.6 ± 0.8Secondary (WD)P orb (d) 0.40375026(16)q 1.27 ± 0.06i (deg) 87.14 ± 0.15R (R ⊙ ) 0.212 ± 0.006 0.0137 ± 0.0004M (M ⊙ ) 0.47 ± 0.03 0.59 ± 0.02T eff (K) 34,500 ± 400 15,900 ± 300Table 3. Correlation coefficients of the different parameters thatwere varied in the MCMC simulations, after applying the Eggletonmass-radius relation constraint.26.0 ± 1.0R 2 i T(assuming corotation) 1 T 2 q(Geier et al. 2010)R 1 0.95 -0.95 0.02 0.02 -0.95R 2 -0.98 0.07 0.02 -0.99Kepler’s treasure chest of EBs – i Steven Bloemen – ESAC– -0.06 29 October -0.0220120.96T 1 0.44 -0.09the relative veinto a single spethe S/N is quifor the combinbined flux-calibselect regions dunresolved lineThe finaltwo separate gin order to derity and He/Hmetals, while tof metals basesdB stars by Btel et al. (2010we derive log glog(He/H) = −position, we finand log(He/H)agreement withlog(He/H) = −et al. (2003) andetermined bymodel grids.The fit demetal solution(Fig. 6), altho


BEAMING + ELLIPSOIDAL + REFLECTIONFaigler & Mazeh 2011


Application of B*** to KOI-13−50Relative Flux [pp500−100–20–−1500 0.2 0.4 0.6 0.8 1Phase150100100Relative Flux [ppm]500−50−100Relative Flux [ppm]500−50BER−1500 0.2 0.4 0.6 0.8 1Phase−1000 0.2 0.4 0.6 0.8 1Phasee Flux [ppm]10050Kepler’s treasure chest of EBs – Steven Bloemen using the – ESAC– fitted coefficients. 29 October Bottom: 2012 we show the sinusoidal signals, in dashed line0Figs. from Shporer et al. 2011, results identical to Mazeh et al. 2011BFig. 4.— Top: phase folded light curve, using the ephemeris derived here. The grayKepler Long Cadence data and the black circles are the binned light curve (errorRsmaller than the markers). The solid line represents the sinusoidal modulation conof the three effects plotted using the amplitudes found here (B=Beaming, E=El


Application of B*** to find binaries300Seven new binaries discovered −0.5 in the Kepler light curves through−1−1−1the BEER method confirmed by radial-velocity observationsΔF/F−24 x 10−4 K10848064120.510−3−40 0.2 0.4 0.6 0.8 1Phase−2−3S. −2.5Faigler and T. Mazeh0 0.2 0.4 0.6 0.8 1PhaseSchool of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences,ΔF/F1.5 x 10−3 K0725476010.50−0.5−1−1.5−2Tel Aviv University, Tel Aviv 69978, Israel 1andS. N. Quinn and D. W. LathamHarvard-Smithsonian Center for Astrophysics,60 Garden St., Cambridge, MA 02138−2.50 0.2 0.4 0.6 0.8 1PhaseandL. Tal-OrKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012ΔF/FΔF/F1.5−1.51.50.50−0.5−1−1.5−22 x 10−4 K080162222 x 10−3 K052637491−2.50 0.2 0.4 0.6 0.8 1Phase1.50.52 x 10−3 K063701961ΔF/FΔF/F321−24 x 10−4 K09512641−40 0.2 0.4 0.6 0.8 1Phase0−1−2−32 x 10−3 K04577324−40 0.2 0.4 0.6 0.8 1PhaseFaigler et al. 2011F0


Table 5.Derived photometric RV period and semi-amplitude together with RVApplication of B*** to find observations period and semi-amplitude for each of the seven binariesSeven new binaries discovered in the Kepler light curves throughthe BEER method confirmed by radial-velocity observationsPhotometry results:Table 5.Derived photometric RV period and semi-amplitude together with RVobservations period and semi-amplitude S. Faigler and forT. each Mazeh of the seven binariesSchool of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences,Photometry results:K10848064 K08016222 K09512641 K07254760 K05263749 K04577324 K06370196Tel Aviv University, Tel Aviv 69978, IsraelandPeriod [days] 3.493.49318 ± 0.01 5.605.60864 ± 0.02 4.654.64588 ± 0.02 2.662.65642 ± 0.01 3.733.72665 ± 0.01 2.33 2.328663 ± 0.01 4.234.23371± 0.01α beam 0.944 ±0.00099 ± 0.025 1.012 ±0.00017 ± 0.023 0.912 ±0.00044 ± 0.036 0.921 ±0.00068 ± 0.024 0.921 ±0.00019 ± 0.022 0.887 ±0.000070 ± 0.025 0.936 ±0.00067 ± 0.030S. N. Quinn and D. W. LathamK beam [km s −1 ] 9.37 ± 0.34 7.19 ± 0.22 15.21 ± 0.72 28.97 ± 0.89 29.14 ± 0.81 36.86 ± 1.10 30.61 ± 1.12RV results:K10848064 K08016222 K09512641 K07254760 K05263749 K04577324 K06370196Period [days] 3.49 ± 0.01 5.60 ± 0.02 4.65 ± 0.02 2.66 ± 0.01 3.73 ± 0.01 2.33 ± 0.01 4.23 ± 0.01α beam 0.944 ± 0.025 1.012 ± 0.023 0.912 ± 0.036 0.921 ± 0.024 0.921 ± 0.022 0.887 ± 0.025 0.936 ± 0.030K beam [km s −1 ] 9.37 ± 0.34 7.19 ± 0.22 15.21 ± 0.72 28.97 ± 0.89 29.14 ± 0.81 36.86 ± 1.10 30.61 ± 1.12RV results:N obs 11 8 12 8 9 8 8K RV [km s −1 ] 9.107 9.495 15.519 29.024 31.428 35.316 40.223Harvard-Smithsonian Center for Astrophysics,60 Garden St., Cambridge, MA 02138Can reveal hundreds/thousands of short periodandbinaries!Minimum N obssecondary 76 ± 115 90± 68 147± 10 12 222 ± 158 279 ± 199 253 ± 178 376 ± 258mass [M Jup ]±0.073 ±0.018 ±0.023 ±0.061 ±0.040 ±0.043 ±0.131L. Tal-OrKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Faigler et al. 2011Period [days] 3.49318 5.60864 4.64588 2.65642 3.72665 2.328663 4.23371±0.00099 ±0.00017 ±0.00044 ±0.00068 ±0.00019 ±0.000070 ±0.00067


Prospect: Photometric Rossiter-McL.The Astrophysical Journal, 745:55(5pp),2012January20The Astrophysical Journal, 745:55(5pp),2012January20Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012Groot 2011


Mass ratio of KOI-74Main sequence A-star + white dwarf in 5d orbitKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Mass ratio of KOI-74Main sequence A-star + white dwarf in 5d orbitVan Kerkwijk et al. 2010:¨ from period, spectral type (à M 1 ),beaming amplitude (à K 1 ): q=0.11¨ from ellipsoidal modulation: q=0.07A-star is fast rotator (v sin(i)=150 km/s)Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Mass ratio of KOI-74White dwarf’s RV amplitude from Rømer delay(predicted by Kaplan 2010)Bloemen, Marsh, Degroote et al., submittedΔt = (K 2 -K 1 ) P/(π c)Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


u One of the 16 known pulsating sdB stars in Kepler fieldu Analysed Q6 – Q10 data + spectroscopyu Found it to be an sdB+WD binaryu Detected and measured the orbit in 3 independent waysu Spectroscopyu Doppler beamingu …Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


e 0.2 µHz. These are certainly measurable with our 460-day datalitudeofobservedthespectrumpeaksams,and the latter obtainedinorbit, vationwhich set withtimings relatesfrequencyto the toresolutioncenter-of-mass the radial-velocityof 0.025µHz.frame amplitude ofIf thetheorbitsystem, K that canis known,equivalentbe, and we adopt one canto the fromsimplycommon spectroscopycorrectapproach or thefor theseofeffectsconversion Doppler-beamingby convertingof observation curve asall observationtimingsor the strongestof blethe 4 have peaksnotintotimingsthe barycentricto the center-of-massframe of the solarframesystem.e time leads toof the system, equivalentIf to the the orbit common is not known, approach one of can conversion use the pulsations of observation as clocksfactor D (seethe shortest exs14%.∆t R = a sdB sin i= K P orb√1 − e2 , timingsderive to the the c(3)ableeffective4 haveexpoenotto barycentric light-travel c 2πframe time that of the corresponds solar system. to the radius of thefactorobservedD (seeams,orbit,Ifwhichthe orbitrelatesis nottoknown,the radial-velocityone can useamplitudethe pulsationsK thatascanclocksberequencieseffectiveand theexpoeobservedlatterare where we introduce the Rømer delay, ∆tobtainedto derive thefromlight-travelspectroscopytimeorthatthecorrespondsDoppler-beaming R , to represent the lighttraveltime.to the radiuscurveofastheorsectionthe strongestof theams,orbit, which relates to the radial-velocity amplitude K that can bere. Theretimeand theleadsis clearlatterto Forobtained from spectroscopy the Doppler-beaming curve asthe theshorteststrongestexis14%.∆t R = a circularsdB sin i orbit,= K Pthe orb√light-travel delay as a function of thethese beatings subdwarf’s position in its orbit 1 − can e2 , written as(3)ransformreof thec c 2πtime leads tothe shortest exissection14%. of the travel time. P orb∆t R = a sdB sin i (= K P orb√ )rotation of thefrequencies are where we introduce the 2πT Rømer 1 − delay, e2 , ∆t R , to represent the light-(3)delay (t) = ∆t c R cos c 2π(t − T orb ) , (4)frequencies. There is clearare where Forwe a circular introduce orbit, the the Rømer light-travel delay, ∆t delay R , toas represent a function theof lighttravelthe, thesesectionbeatingsof thewhere subdwarf’s Ttime. orb isposition the timeinatits which orbitthe cansubdwarf be written is as closest to the Sunransform. There isofclearthe in its orbit, corresponding to the orbital phase listed in Table 2.sation For a circular orbit, the light-travel delay as a function of the, theserotation frequennationfrequen-(t − T orb ) , (4)( )beatingsof thesubdwarf’sWe did notpositiondetectin 2π anyitssecondorbitcanorbethird-harmonicT delay (t) = ∆t R coswritten aspeaks, neitherfor the orbit norP for the pulsations. Hence, for sinusoidalransform of the= f ( orb 3 − f 2 − f 1)rotation of the signals the Kepler light curve of KIC 11558725 can be approximatedwhere T delay (t) by T orbe 4, we find 132π= ∆t is R thecostime (t − T orb ) , (4)f =0 within thePat which the subdwarf is closest to the Sunorbuencies¨ are inbinationsExpected in its orbit, signal: corresponding to the orbital phase listed in Table 2.lsation frequennationfrequenisan where WeT did orb is not the detect ( time any at which second- ) the or subdwarf third-harmonic is closestpeaks, to thenei-ther in itsfor orbit, thecorresponding orbit nor for the to the pulsations. orbital phase Hence, listed forinsinusoidalTable 2.Sunlsation=forfthe3 −listfrequennationf 2 −of∆I(t)2πf 1= Asignalse Wethe B sin (t − TdidKeplernot detectlightanycurve orb )IP orb secondofKICor third-harmonic11558725 can bepeaks,approximatedneitherfor4, wefrequenfind13efby∑the orbit nor for the pulsations. Hence, for sinusoidal==0ourfwithinobserved3 − f 2 −the + Af i,puls sin ( 2πF i,puls (t − T i,puls + T delay (t)) ) , (5)1quenciesm offset which signals the Kepler light curve of KIC 11558725 can be approximatedbye 4, we findare inbinationsill 13δenough suchf =0 withinisthean( )6cies forlookstheKepler’s arelistlikeinbinationsis an where all individual ( orbof∆I(t)2πwhere thefrequencies by= Afirst treasure I chest of B sinterm describes (t − TEBs – PSteven Bloemen orb ) the orbital beaming effect, and– ESAC– 29 October 2012∑ pulsations )ket theourfrequencyobserved ∆I(t)2π(are affected by the same)orbitallight-travel delay T delay (t). Here, the phase of the individual pul-Rømer delay in pulsation signals¨ ‘Rømer delay’ (light travel time) due to size of the orbit¨ Time delay in light of sdB as a function of timeAssuming circular orbitT orb = sdB closest to the Sunß Beamingß Pulsations with Rømer delay


Signature of time delay in FTcModel amplitude706050403020100706050403020100Model with 25s delayPlain model3072.5 3073.0 3073.5 3074.0 3074.5 3075.0 3075.5 3076.0Frequency [µHz]Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Correct times to barycentre of binaryaAmplitude [ppm]706050403020100706050403020100ObservedCorrected3072.5 3073.0 3073.5 3074.0 3074.5 3075.0 3075.5 3076.0Frequency [µHz]Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Amplitude of modes for different orbit sizesb706050Amplitude [ppm]403020f=3073.5f=3060.010f=3075.0f=3102.3f=3103.9020 10 0 10 20 30 40 50 60Rømer delay [s]Optimal value: Rømer delay of 26.4 ± 0.7s à K= 57.3 ± 1.5 km/s(compare to spectroscopy: K 1 = 58.1 ± 1.7 km/s)Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


of theof thequen-quen-2 − f 1nd 13in there inisanlist ofervedhichsuchs likeies byuencyh ranationsn ourcomwesttions,Thesend wes andperiodic signals was σ=1900ppm .0.2 µHz. These are certainly measurable withThe ( standard deviation ) in the Fourier amplitude spectrum set with frequency resolution of 0.025µHz. If t2πJ. H. Telting et al.: KIC 11558725: a 10-day beaming sdBV+WD binaryTFittingdelay (t) = ∆t R cosof the original(t −dataTpulsationsorb )amounts,to σ FT =4.2 ppm, and we(4)adopt one can simply correct for these effects by conP orbwith Rømer delayThe4σ FT standard=17 ppmdeviationas the thresholdof the dataofaftersignificanceremoval ofofallthesignificantpeaks inK=58vationkmtimingss −1 , evento theforcenter-of-massg-modes givesframefrequencof tperiodicthe Fouriersignalsamplitudewas σ=1900ppmspectrum..0.2alentµHz.to theThesecommonare certainlyapproachmeasurableof conversionwithoWe note that the observed amplitudes in Table 4 have not ings to the barycentric frame of the solar systewhere T orb is the time The at standard whichdeviation the subdwarf in the Fourier is closest amplitude to thespectrumSun set with frequency resolution of 0.025µHz. If thofbeenthecorrectedoriginal datafor theamountsKeplertodecontaminationσfactor D (see If the orbit is not known, one can use the puin its orbit, corresponding to the orbital phase FT =4.2 ppm, and we adopt one can simply correct for these effects by conlisted in Table 2.4σabove), nor for the amplitude smearing due to the effective exposureto derive the light-travel time that corresponds tFT =17 ppm as the threshold of significance of the peaks in vation timings to the center-of-mass frame of thWe did not the detect Fouriertime any ofamplitude second- 58.8 seconds.spectrum. or third-harmonic Both effects causepeaks, the observed neitherfor the orbit We nornote to beamplitudesalent orbit, towhich the common relates to approach the radial-velocity of conversion ampli offor thatsmallerthe the pulsations. observedthan the intrinsicamplitudesamplitudes,Hence, for in Tableandsinusoidal 4 havethe latternot ings obtained to thefrom barycentric spectroscopy frame or of the Doppler-be solar systemNLLS signals thefit Kepler to beenaffects mostly the shortest periods (p-modes). For the strongestpulsation, light 70 correctedcurve with fora period ofthe KICKeplerof11558725 decontamination3641.1 s,modes,thecan exposure befactorapproximatedby a decrease of the amplitude of 4.3%, while for the shortest ex-timewith D (seeleads tofree If the amplitudes,∆t R =frequencies, phases, and Rømer delaya orbit is notsdB sin i= K known,P orb√one can use the puabove), nor for the amplitude smearing due to the effective exposurtractedtime period of 58.8 of 197.9 seconds. s the Both amplitude effects decrease cause the is observed 14%. am-orbit, whichcrelates tocthe 2πradial-velocity amplitto derive the light-travel time 1 that − e2 corresponds , toplitudes to be smaller than the intrinsic amplitudes, and the latter obtained from spectroscopy or the Doppler-beaaffectsTomostlyillustratethetheshortestfactperiodsthat all(p-modes).pulsationalForfrequenciesthe strongestare where we introduce the Rømer delay, ∆t R , to rpulsation,present ( throughoutwith a period ) theofKepler3641.1run,s, theweexposureshow a sectiontime leadsof thetotravel time.∆I(t) aFourierdecrease 2π transformof the amplitudein a dynamicof 4.3%,formwhilein Figurefor the4. Thereshortestis clearextractedP period of 197.9 s the amplitude decrease is 14%. subdwarf’s position in its orbit can be written∆t R = For a sdB sin ia circular = orbit, K P orb√the light-travel 1 − e2 , delay a= A B sinbeating(t among − T orb the)stronger frequencies; in fact, these beatingsc c 2πIorb∑showToupillustrate+ A i,puls sin ( as resolvedthefrequenciesfact that allinpulsationalthe Fourier2πF i,puls (t − T i,puls + T delay (t)) ) frequenciestransform ofarethewhere we introduce ( the Rømer delay, ) ∆t R , to representfull Keplerthroughoutdata set,theandKeplermay berun,attributedwe showto thearotation of thesubdwarf (Sect. 7)., section (5) of the travelTtime. 2πdelay (t) = ∆t R cos (t − T orb ) ,Fourier transform in a dynamic form in Figure 4. There is clearPiFor a circular orbit, orb the light-travel delay asbeating among the stronger frequencies; in fact, these beatings subdwarf’s position in its orbit can be written ashow 4.1. up Combination as resolved frequencies in the Fourier transform of the where T orb is the time at which the subdwarf is( )the firstfull term Kepler describes data set, and themay orbital be attributed beaming to the effect, rotation and of the in its orbit, corresponding 2π to the orbital phaseWe do not find evidence for harmonics of the pulsation frequencies.delay Weà whereRømer all individualsubdwarfpulsations(Sect. 7).Tdo, however, of arefind 26.5 affectedevidenceby± forthecombination 1.5s same orbital delay We (t) = did∆t not R cos detect any (t −second- T orb ) or , third-harfrequen-T delay When (t). computing Here, the thephase residual ofrequency the individual δ f = f 3P orbther for the orbit nor for the pulsations. Henlight-travel delaycies. pulsations,T i,puls , is 4.1. for expressed all Combination combinations the frequencies oftime 168 frequencies domain rather in Table than 4, we as find an 13− f 2 − f 1 signals the Kepler light curve of KIC 1155872where T orb is the time at which the subdwarf ismated byangle. Note thatcombinations the above sum that are of consistent sine curves withisa equivalent residual à Kδ f =0 1 to =57.5 within the thein its±orbit,3.2correspondingkm/sto the orbital phase lWe do not find evidence for harmonics of the pulsation frequencies.errors of the frequencies. Thirty-five different frequencies are involvedWe did not detect any second- or third-harmmodel that we fit as We partdo, in theseofhowever, the13prewhitening find evidencecombinations.procedure for combination described frequencies.When computing the residual frequency δ f = f 3 − f 2 − f 1in Sect. 4, with the addition of a phase (compare One of thedelay that introduces to combinations spectroscopy: is an ther for the orbitjust K 1 = 58.1( nor for the pulsations.± 1.7 km/s)) Hencorbital alias discussed in Sect. 5.1. See Table 6 for the list of signals ∆I(t) the Kepler light 2π curve of KIC 11558725for all combinations of 168 frequencies in Table 4, we find 13 = A B sin (t − T orb )one extra parameter, frequency i.e. combinations. the amplitude ∆t R of the light-travel delay.errorsmated I by P orbcombinations that are consistent with a residual δ f =0 within the∑Toofinvestigatethe frequencies.the significanceThirty-fiveofdifferentthis, wefrequenciestake our observedare involved+ A i,puls sin ( 2πF i,puls (t − T i,puls + Tfrequencies and perturb each of them by a random offset whichiWe apply the isabove in thesebig enough formula 13 combinations.to upset (5) real tocombinations, derive One a of third the combinationsbutindependentis an( )orbital alias discussed in Sect. 5.1. See Tablesmall6 forenoughthe listsuchof∆I(t)2πKepler’s measurement treasure of chest that the the of radial-velocity EBs distribution – Steven of Bloemen these amplitude randomised – ESAC– of the frequencies 29 subdwarf October looks in 2012frequency combinations.like= A B sin (t − T orb )where I the first term P orb describes the orbital beKIC 11558725. that For Toof this investigatethe observed purpose, thedistribution.significance we included Weof this,perturb the weabove takethe frequenciesour phase observedby ∑where+all individual A i,puls sin pulsations ( 2πF i,puls (t are − Taffected i,puls + Tbyd


Eclipse timing variations(non-eclipsing) third bodies detected in timingvariations of eclipses[Ford et al. 2012, Steffen et al. 2012]


A few examples…Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


A few examples…Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


A few examples…Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


A few examples…Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Transiting circumbinary planets


Kepler-16Doyle et al. 2011Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler-16Doyle et al. 2011Planet mass: 0.33M J (~Saturn)Planet radius: 0.75R JPlanet period: 229-dKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler-34Welsh et al. 2012Planet mass: 0.22 M JPlanet radius: 0.76 R JPlanet period: 288 dStellar masses: 1.04 and 1.02 M sunBinary orbital period: 28 dKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler-35Welsh et al. 2012Planet mass: 0.127 M JPlanet radius: 0.73 R JPlanet period: 131 dStellar masses: 0.89 and 0.81 M sunBinary orbital period: 21 dKepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Illustration Kepler 34/35 press release© Lynette R. Cook – http://extrasolar.spaceart.org


Seasons on a CPB (Kepler-34 & 35)Kepler’s treasure chest of EBs – Steven Bloemen – ESAC– 29 October 2012


Kepler-47: multiplanet circumbinary2 planets orbiting a binaryKepler-47c in the habitablezone, but not rockyDownloaded from ww. Planetary transit time anddurationvariations.(Left)erved minus expected times of transit computed fromrephemerisareshownversustime(an“O-C” curve).ngles show the measured deviations, and the filledare the predictions from the photometric-dynamicalFour transits of the inner planet occurred in data gapsons of corrupted data. (Top right) TheO-Cvaluesofer planet are shown as a function of the binary phase,its theatprimary same Kepler’s eclipse binary occurs treasure phase. at phase chest 0.0 of EBs and – the Steven Bloemen – ESAC– 29 October 2012ary eclipse is at phase 0.487. Two cycles have beenfor clarity. The solid curve is the predicted deviationAll circumbinary planets found so farare Saturn size or smaller!

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