We report Warm Spitzer full-orbit phase observations of WASP-12b at 3.6 and 4.5 µm. This extremely inflated hot Jupiter is thought to be overflowing its Roche lobe, undergoing mass loss, accretion onto its host star, and has been claimed to have a C/O ratio in excess of unity. We are able to measure the transit depths, eclipse depths, thermal and ellipsoidal phase variations at both wavelengths. The large amplitude phase variations, combined with the planet's previously-measured day-side spectral energy distribution, is indicative of non-zero Bond albedo and very poor day-night heat redistribution. The transit depths in the mid-infrared -(R p /R * ) 2 = 0.0123(3) and 0.0111(3) at 3.6 and 4.5 µm, respectively-indicate that the atmospheric opacity is greater at 3.6 than at 4.5 µm, in disagreement with model predictions, irrespective of C/O ratio. The secondary eclipse depths are consistent with previous studies: F day /F * = 0.0038(4) and 0.0039(3) at 3.6 and 4.5 µm, respectively. We do not detect ellipsoidal variations at 3.6 µm, but our parameter uncertainties -estimated via prayer-bead Monte Carlo-keep this non-detection consistent with model predictions. At 4.5 µm, on the other hand, we detect ellipsoidal variations that are much stronger than predicted. If interpreted as a geometric effect due to the planet's elongated shape, these variations imply a 3:2 ratio for the planet's longest:shortest axes and a relatively bright day-night terminator. If we instead presume that the 4.5 µm ellipsoidal variations are due to uncorrected systematic noise and we fix the amplitude of the variations to zero, the best fit 4.5 µm transit depth becomes commensurate with the 3.6 µm depth, within the uncertainties. The relative transit depths are then consistent with a Solar composition and short scale height at the terminator. Assuming zero ellipsoidal variations also yields a much deeper 4.5 µm eclipse depth, consistent with a Solar composition and modest temperature inversion. We suggest future observations that could distinguish between these two scenarios. 11 We follow Agol et al. (2010), who compared many centroiding algorithms and found this one to be optimal. Using fluxweighted centroiding instead of PSF-fitting results in slightly worse χ 2 , commensurate correlated noise as measured using β (see first Section 4.1), and consistent astrophysical parameters.

Aims. Extra-solar planet search programs require high-precision velocity measurements. They need to determine how to differentiate between radial-velocity variations due to Doppler motion and the noise induced by stellar activity. Methods. We monitored the active K2V star HD 189 733 and its transiting planetary companion, which has a 2.2-day orbital period. We used the high-resolution spectograph SOPHIE mounted on the 1.93-m telescope at the Observatoire de Haute-Provence to obtain 55 spectra of HD 189 733 over nearly two months. We refined the HD 189 733b orbit parameters and placed limits on both the eccentricity and long-term velocity gradient. After subtracting the orbital motion of the planet, we compared the variability in spectroscopic activity indices with the evolution in the radial-velocity residuals and the shape of spectral lines.Results. The radial velocity, the spectral-line profile, and the activity indices measured in He i (5875.62 Å), Hα (6562.81 Å), and both of the Ca ii H&K lines (3968.47 Å and 3933.66 Å, respectively) exhibit a periodicity close to the stellar-rotation period and the correlations between them are consistent with a spotted stellar surface in rotation. We used these correlations to correct for the radialvelocity jitter due to stellar activity. This results in achieving high precision in measuring the orbital parameters, with a semi-amplitude K = 200.56 ± 0.88 m s −1 and a derived planet mass of M P = 1.13 ± 0.03 M Jup .

We used the Wide-field Infrared Camera on the Canada-France-Hawaii telescope to observe four transits of the super-Earth planet GJ 1214b in the near-infrared. For each transit we observed in two bands nearly-simultaneously by rapidly switching the WIRCam filter wheel back and forth for the duration of the observations. By combining all our J-band (∼1.25 µm) observations we find a transit depth, analogous to the planet-to-star radius ratio squared, in this band of (R P J /R * ) 2 =1.338±0.013% -a value consistent with the optical transit depth reported by Charbonneau and collaborators. However, our best-fit combined Ks-band (∼2.15 µm) transit depth is deeper: (R P Ks /R * ) 2 =1.438±0.019%. Formally our Ks-band transits are deeper than the J-band transits observed simultaneously by a factor of (R P Ks /R P J ) 2 =1.072±0.018 -a 4σ discrepancy. The most straightforward explanation for our deeper Ks-band transit depth is a spectral absorption feature from the limb of the atmosphere of the planet; for the spectral absorption feature to be this prominent the atmosphere of GJ 1214b must have a large scale height and a low mean molecular weight. That is, its atmosphere would have to be hydrogen/helium dominated and this planet would be better described as a mini-Neptune. However, recently published observations from 0.78 -1.0 µm, by Bean and collaborators, show a lack of spectral features and transit depths consistent with those obtained by Charbonneau and collaborators. The most likely atmospheric composition for GJ 1214b that arises from combining all these observations is less clear; if the atmosphere of GJ 1214b is hydrogen/helium dominated then it must have either a haze layer that is obscuring transit depth differences at shorter wavelengths, or significantly different spectral features than current models predict. Our observations disfavour a water-world composition, but such a composition will remain a possibility for GJ 1214b, until observations reconfirm our deeper Ks-band transit depth or detect features at other wavelengths.

We have obtained extensive photometric observations of the polluted white dwarf WD 1145+017 which has been reported to be transited by at least one, and perhaps several, large asteroids with dust emission. Observation sessions on 37 nights spanning 2015 November to 2016 January with small to modest size telescopes have detected 237 significant dips in flux. Periodograms reveal a significant periodicity of 4.5004 hours consistent with the dominant ("A") period detected with K2. The folded light curve shows an hour-long depression in flux with a mean depth of nearly 10%. This depression is, in turn, comprised of a series of shorter and sometimes deeper dips which would be unresolvable with K2. We also find numerous dips in flux at other orbital phases. Nearly all of the dips associated with this activity appear to drift systematically in phase with respect to the "A" period by about 2.5 minutes per day with a dispersion of ∼0.5 min/d, corresponding to a mean drift period of 4.4928 hours. We are able to track ∼15 discrete drifting features. The "B"-"F" periods found with K2 are not detected, but we would not necessarily have expected to see them. We explain the drifting motion as due to smaller fragmented bodies that break off from the asteroid and go into a slightly smaller orbit. In this interpretation, we can use the drift rate to determine the mass of the asteroid, which we find to be ≈ 10 23 grams, or about 1/10th the mass of Ceres.