- ID:
- ivo://CDS.VizieR/J/ApJ/788/92
- Title:
- The hot Jupiter Kepler-13Ab planet's occultation
- Short Name:
- J/ApJ/788/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period planets orbiting a hot A-type star, making it one of the hottest planets currently known. The availability of Kepler data allows us to measure the planet's occultation (secondary eclipse) and phase curve in the optical, which we combine with occultations observed by warm Spitzer at 4.5 {mu}m and 3.6 {mu}m and a ground-based occultation observation in the K_s_ band (2.1 {mu}m). We derive a day-side hemisphere temperature of 2750+/-160 K as the effective temperature of a black body showing the same occultation depths. Comparing the occultation depths with one-dimensional planetary atmosphere models suggests the presence of an atmospheric temperature inversion. Our analysis shows evidence for a relatively high geometric albedo, A_g_=0.33_-0.06_^+0.04^. While measured with a simplistic method, a high A_g_ is supported also by the fact that the one-dimensional atmosphere models underestimate the occultation depth in the optical. We use stellar spectra to determine the dilution, in the four wide bands where occultation was measured, due to the visual stellar binary companion 1.15"+/-0.05" away. The revised stellar parameters measured using these spectra are combined with other measurements, leading to revised planetary mass and radius estimates of M_p_=4.94-8.09 M_J_ and R_p_=1.406+/-0.038 R_J_. Finally, we measure a Kepler midoccultation time that is 34.0+/-6.9 s earlier than expected based on the midtransit time and the delay due to light-travel time and discuss possible scenarios.
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- ID:
- ivo://CDS.VizieR/J/A+A/544/A9
- Title:
- The International Deep Planet Survey. I.
- Short Name:
- J/A+A/544/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Breakthrough direct detections of planetary companions orbiting A-type stars confirm the existence of massive planets at relatively large separations, but dedicated surveys are required to estimate the frequency of similar planetary systems. To measure the first estimation of the giant exoplanetary systems frequency at large orbital separation around A-stars, we have conducted a deep-imaging survey of young (8-400Myr), nearby (19-84pc) A- and F-stars to search for substellar companions in the ~10-300AU range. The sample of 42 stars combines all A-stars observed in previous AO planet search surveys reported in the literature with new AO observations from VLT/NaCo and Gemini/NIRI. It represents an initial subset of the International Deep Planet Survey (IDPS) sample of stars covering M- to B-stars. The data were obtained with diffraction-limited observations in H- and Ks-band combined with angular differential imaging to suppress the speckle noise of the central stars, resulting in typical 5-sigma detection limits in magnitude difference of 12mag at 1", 14mag at 2" and 16mag at 5" which is sufficient to detect massive planets. A detailed statistical analysis of the survey results is performed using Monte Carlo simulations. Considering the planet detections, we estimate the fraction of A-stars having at least one massive planet (3-14M_Jup_) in the range 5-320AU to be inside 5.9-18.8% at 68% confidence, assuming a flat distribution for the mass of the planets. By comparison, the brown dwarf (15-75M_Jup_) frequency for the sample is 2.0-8.9% at 68% confidence in the range 5-320AU. Assuming power law distributions for the mass and semimajor axis of the planet population, the AO data are consistent with a declining number of massive planets with increasing orbital radius which is distinct from the rising slope inferred from radial velocity (RV) surveys around evolved A-stars and suggests that the peak of the massive planet population around A-stars may occur at separations between the ranges probed by existing RV and AO observations. Finally, we report the discovery of three new close M-star companions to HIP 104365 and HIP 42334.
- ID:
- ivo://CDS.VizieR/J/AJ/154/49
- Title:
- Transiting Exoplanet Monitoring Project. II. HAT-P-33
- Short Name:
- J/AJ/154/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 10 R-band photometric observations of eight different transits of the hot Jupiter HAT-P-33b, which has been targeted by our Transiting Exoplanet Monitoring Project. The data were obtained by two telescopes at the Xinglong Station of National Astronomical Observatories of China (NAOC) from 2013 December through 2016 January, and exhibit photometric scatter of 1.6-3.0mmag. After jointly analyzing the previously published photometric data, radial-velocity (RV) measurements, and our new light curves, we revisit the system parameters and orbital ephemeris for the HAT-P-33b system. Our results are consistent with the published values except for the planet to star radius ratio (R_P_/R_*_), the ingress/egress duration ({tau}) and the total duration (T_14_), which together indicate a slightly shallower and shorter transit shape. Our results are based on more complete light curves, whereas the previously published work had only one complete transit light curve. No significant anomalies in Transit Timing Variations (TTVs) are found, and we place upper mass limits on potential perturbers, largely supplanting the loose constraints provided by the extant RV data. The TTV limits are stronger near mean-motion resonances, especially for the low-order commensurabilities. We can exclude the existence of a perturber with mass larger than 0.6, 0.3, 0.5, 0.5, and 0.3M_{Earth}_ near the 1:3, 1:2, 2:3, 3:2, and 2:1 resonances, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/809/77
- Title:
- Transiting Exoplanet Survey Satellite (TESS)
- Short Name:
- J/ApJ/809/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) is a NASA-sponsored Explorer mission that will perform a wide-field survey for planets that transit bright host stars. Here, we predict the properties of the transiting planets that TESS will detect along with the EB stars that produce false-positive photometric signals. The predictions are based on Monte Carlo simulations of the nearby population of stars, occurrence rates of planets derived from Kepler, and models for the photometric performance and sky coverage of the TESS cameras. We expect that TESS will find approximately 1700 transiting planets from 2x10^5^ pre-selected target stars. This includes 556 planets smaller than twice the size of Earth, of which 419 are hosted by M dwarf stars and 137 are hosted by FGK dwarfs. Approximately 130 of the R<2R_{Earth}_ planets will have host stars brighter than Ks=9. Approximately 48 of the planets with R<2R_{Earth}_ lie within or near the habitable zone (0.2<S/S_{Earth}_<2); between 2 and 7 such planets have host stars brighter than Ks=9. We also expect approximately 1100 detections of planets with radii 2-4R_{Earth}_, and 67 planets larger than 4R_{Earth}_. Additional planets larger than 2R_{Earth}_ can be detected around stars that are not among the pre-selected target stars, because TESS will also deliver full-frame images at a 30-minute cadence. The planet detections are accompanied by over 1000 astrophysical false positives. We discuss how TESS data and ground-based observations can be used to distinguish the false positives from genuine planets. We also discuss the prospects for follow-up observations to measure the masses and atmospheres of the TESS planets.
- ID:
- ivo://CDS.VizieR/J/AJ/153/191
- Title:
- Transiting planet GJ 1132
- Short Name:
- J/AJ/153/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detecting the atmospheres of low-mass, low-temperature exoplanets is a high-priority goal on the path to ultimately detecting biosignatures in the atmospheres of habitable exoplanets. High-precision HST observations of several super-Earths with equilibrium temperatures below 1000K have to date all resulted in featureless transmission spectra, which have been suggested to be due to high-altitude clouds. We report the detection of an atmospheric feature in the atmosphere of a 1.6M_{Earth}_ exoplanet, GJ 1132 b, with an equilibrium temperature of ~600K and orbiting a nearby M dwarf. We present observations of nine transits of the planet obtained simultaneously in the griz and JHK passbands. We find an average radius of 1.43+/-0.16R_{Earth}_ for the planet, averaged over all the passbands, and a radius of 0.255+/-0.023R_{sun}_ for the star, both of which are significantly greater than previously found. The planet radius can be decomposed into a "surface radius" at ~1.375R_{Earth}_ overlaid by atmospheric features that increase the observed radius in the z and K bands. The z-band radius is 4{sigma} higher than the continuum, suggesting a strong detection of an atmosphere. We deploy a suite of tests to verify the reliability of the transmission spectrum, which are greatly helped by the existence of repeat observations. The large z-band transit depth indicates strong opacity from H_2_O and/or CH_4_ or a hitherto-unconsidered opacity. A surface radius of 1.375+/-0.16R_{Earth}_ allows for a wide range of interior compositions ranging from a nearly Earth-like rocky interior, with ~70% silicate and ~30% Fe, to a substantially H_2_O-rich water world.
- ID:
- ivo://CDS.VizieR/J/AJ/143/95
- Title:
- Transit light curves of HAT-P-12
- Short Name:
- J/AJ/143/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric data of the transiting planet HAT-P-12b observed in 2011. Our three transit curves are modeled using the JKTEBOP code and adopting the quadratic limb-darkening law. Including our measurements, 18 transit times spanning about 4.2yr were used to determine the improved ephemeris with a transit epoch of 2454187.85560+/-0.00011BJD and an orbital period of 3.21305961+/-0.00000035days. The physical properties of the star-planet system are computed using empirical calibrations from eclipsing binary stars and stellar evolutionary models, combined with both our transit parameters and previously known spectroscopic results. We found that the absolute dimensions of the host star are M_A_=0.73+/-0.02M{sun}, R_A_=0.70+/-0.01R_{sun}_, log g_A_=4.61+/-0.02, p_A_=2.10+/-0.09{rho}{sun}, and L_A_=0.21+/-0.01L_{sun}_. The planetary companion has M_b_=0.21+/-0.01M_{Jup}_, R_b_=0.94+/-0.01R_{Jup}_, log g_b_=2.77+/-0.02, {rho}_b_=0.24+/-0.01{rho}_{Jup}_, and T_eq_=960+/-14K. Our results agree well with standard models of irradiated gas giants with a core mass of 11.3M_{earth}_.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A46
- Title:
- Transit observations of GJ1214b
- Short Name:
- J/A+A/538/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- GJ1214b, the 6.55 Earth-mass transiting planet recently discovered by the MEarth team, has a mean density of 35% of that of the Earth. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. In the case of a hydrogen-rich atmosphere, molecular absorption and scattering processes may result in detectable radius variations as a function of wavelength. The aim of this paper is to measure these variations. We have obtained observations of the transit of GJ1214b in the r- and I-band with the Isaac Newton Telescope (INT), in the g-, r-, i- and z-bands with the 2.2m MPI/ESO telescope, in the Ks-band with the Nordic Optical Telescope (NOT), and in the Kc-band with the William Herschel Telescope (WHT). By comparing the transit depth between the the different bands, which is a measure for the planet-to-star size ratio, the atmosphere is investigated. We do not detect clearly significant variations in the planet-to-star size ratio as function of wavelength. Although the ratio at the shortest measured wavelength, in g-band, is 2sigma larger than in the other bands. The uncertainties in the Ks and Kc bands are large, due to systematic features in the light curves. The tentative increase in the planet-to-star size ratio at the shortest wavelength could be a sign of an increase in the effective planet-size due to Rayleigh scattering, which would require GJ1214b to have a hydrogen-rich atmosphere. If true, then the atmosphere has to have both clouds, to suppress planet-size variations at red optical wavelengths, as well as a sub-solar metallicity, to suppress strong molecular features in the near- and mid-infrared However, star spots, which are known to be present on the hoststar's surface, can (partly) cancel out the expected variations in planet-to-star size ratio, because the lower surface temperature of the spots causes the effective size of the star to vary with wavelength. A hypothetical spot-fraction of 10%, corresponding to an average stellar dimming of 5% in the i-band, would be able to raise the near- and mid-infrared points sufficiently with respect to the optical measurements to be inconsistent with a water-dominated atmosphere. Modulation of the spot fraction due to the stellar rotation would in such case cause the observed flux variations of GJ1214.
- ID:
- ivo://CDS.VizieR/J/A+A/533/A114
- Title:
- Transit of super-Earth 55 Cnc e
- Short Name:
- J/A+A/533/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the detection of a transit of the super-Earth 55 Cnc e with warm Spitzer in IRAC's 4.5um band.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A30
- Title:
- Transits of HAT-P-16 and WASP-21
- Short Name:
- J/A+A/557/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first photometric follow-up of the transiting planet HAT-P-16 b, and new photometric observations of WASP-21 b, obtained simultaneously with two medium-class telescopes located in different countries, using the telescope defocussing technique. We modeled these and other published data in order to estimate the physical parameters of the two planetary systems.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A26
- Title:
- TrES-3b UBVIz' light curves
- Short Name:
- J/A+A/608/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Transit events of extrasolar planets offer the opportunity to study the composition of their atmospheres. Previous work on transmission spectroscopy of the close-in gas giant TrES-3 b revealed an increase in absorption towards blue wavelengths of very large amplitude in terms of atmospheric pressure scale heights, too large to be explained by Rayleigh- scattering in the planetary atmosphere. We present a follow-up study of the optical transmission spectrum of the hot Jupiter TrES-3 b to investigate the strong increase in opacity towards short wavelengths found by a previous study. Furthermore, we aim to estimate the effect of stellar spots on the transmission spectrum. This work uses previously published long slit spectroscopy transit data of the Gran Telescopio Canarias (GTC) and published broad band observations as well as new observations in different bands from the near-UV to the near-IR, for a homogeneous transit light curve analysis. Additionally, a long-term photometric monitoring of the TrES-3 host star was performed. Our newly analysed GTC spectroscopic transit observations show a slope of much lower amplitude than previous studies. We conclude from our results the previously reported increasing signal towards short wavelengths is not intrinsic to the TrES-3 system. Furthermore, the broad band spectrum favours a flat spectrum. Long-term photometric monitoring rules out a significant modification of the transmission spectrum by unocculted star spots.