Browsing by Subject "hot jupiter"
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Item A Misaligned Prograde Orbit For Kepler-13 Ab Via Doppler Tomography(2014-07) Johnson, Marshall C.; Cochran, William D.; Albrecht, Simon; Dodson-Robinson, Sarah E.; Winn, Joshua N.; Gullikson, Kevin; Johnson, Marshall C.; Cochran, William D.Transiting planets around rapidly rotating stars are not amenable to precise radial velocity observations, such as are used for planet candidate validation, as they have wide, rotationally broadened stellar lines. Such planets can, however, be observed using Doppler tomography, wherein stellar absorption line profile distortions during transit are spectroscopically resolved. This allows the validation of transiting planet candidates and the measurement of the stellar spin-planetary orbit (mis) alignment, which is an important statistical probe of planetary migration processes. We present Doppler tomographic observations that provide direct confirmation of the hot Jupiter Kepler-13 Ab and also show that the planet has a prograde, misaligned orbit with lambda = 58 degrees.6 +/- 2 degrees.0. Our measured value of the spin-orbit misalignment is in significant disagreement with the value of lambda = 23 degrees +/- 4 degrees previously measured by Barnes et al. (2011) from the gravity-darkened Kepler light curve. We also place an upper limit of 0.75 M-circle dot (95% confidence) on the mass of Kepler-13 C, the spectroscopic companion to Kepler-13 B, which is the proper-motion companion of the planet host star Kepler-13 A.Item A Spitzer Infrared Spectrograph Study Of Debris Disks Around Planet-Host Stars(2011-01) Dodson-Robinson, Sarah E.; Beichman, C. A.; Carpenter, John M.; Bryden, Geoffrey; Dodson-Robinson, Sarah E.Since giant planets scatter planetesimals within a few tidal radii of their orbits, the locations of existing planetesimal belts indicate regions where giant planet formation failed in bygone protostellar disks. Infrared observations of circumstellar dust produced by colliding planetesimals are therefore powerful probes of the formation histories of known planets. Here we present new Spitzer infrared spectrograph (IRS) spectrophotometry of 111 solar-type stars, including 105 planet hosts. Our observations reveal 11 debris disks, including two previously undetected debris disks orbiting HD 108874 and HD 130322. Combining the 32 mu m spectrophotometry with previously published MIPS photometry, we find that the majority of debris disks around solar-type stars have temperatures in the range 60 less than or similar to T-dust less than or similar to 100 K. Assuming a dust temperature T-dust = 70 K, which is representative of the nine debris disks detected by both IRS and MIPS, debris rings surrounding Sun-like stars orbit between 15 and 240 AU depending on the mean particle size. Our observations imply that the planets detected by radial-velocity searches formed within 240 AU of their parent stars. If any of the debris disks studied here have mostly large, blackbody emitting grains, their companion giant planets must have formed in a narrow region between the ice line and 15 AU.