The atmospheres of ultra-hot Jupiters are commonly considered to be at thermochemical equilibrium. We aim to provide disequilibrium chemistry maps for a global understanding of the chemistry in HAT-P-7b's atmosphere and assess the importance of disequilibrium chemistry on UHJs.
We apply a hierarchical modelling approach utilising 97 1D atmospheric profiles from 3D GCM of HAT-P-7b. For each 1D profile, we evaluate our kinetic cloud formation model consistently with the local gas-phase composition in chemical equilibrium. We then evaluate quenching results from a zeroth-order approximation in comparison to a kinetic gas-phase approach.
We find that the zeroth-order approach of estimating quenching points agrees well with the full gas-kinetic modeling results. Chemical disequilibrium has the greatest effect on the nightside and morning abundance of species such as H, H$_2$O, CH$_4$, CO$_2$, HCN, and all C$_n$H$_m$ molecules; heavier C$_n$H$_m$ molecules are more affected by disequilibrium processes. CO abundance, however, is affected only marginally. While dayside abundances also notably change, those around the evening terminator of HAT-P-7b are the least affected by disequilibrium processes. The latter finding may partially explain the consistency of observed transmission spectra of UHJs with atmospheres in thermochemical equilibrium. Photochemistry only negligibly affects molecular abundances and quenching levels.
In general, the quenching points of HAT-P-7b's atmosphere are at much lower pressures in comparison to the cooler hot-jupiters. We propose several avenues to look for the effect of disequilibrium processes on UHJs that are, in general, based on abundance and opacity measurements at different local times. It remains a challenge to completely disentangle this from the chemical effects of clouds and that of a primordial non-solar abundance.
We report the discovery of four transiting hot Jupiters from the HATSouth survey: HATS-39b, HATS-40b, HATS41b and HATS-42b. These discoveries add to the growing number of transiting planets orbiting moderately bright (12.5 < V < 13.7) F dwarf stars on short (2-5 day) periods. The planets have similar radii, ranging from 1.33(+0.29/-0.20) R_J for HATS-41b to 1.58(+0.16/-0.12) R_J for HATS-40b. Their masses and bulk densities, however, span more than an order of magnitude. HATS-39b has a mass of 0.63 +/- 0.13 M_J, and an inflated radius of 1.57 +/- 0.12 R_J, making it a good target for future tr…
We report six new inflated hot Jupiters (HATS-25b through HATS-30b) discovered using the HATSouth global network of automated telescopes. The planets orbit stars with $V$ magnitudes in the range $\sim 12-14$ and have masses in the largely populated $0.5M_J-0.7M_J$ region of parameter space but span a wide variety of radii, from $1.17R_J$ to $1.75 R_J$. HATS-25b, HATS-28b, HATS-29b and HATS-30b are typical inflated hot Jupiters ($R_p = 1.17-1.26R_J$) orbiting G-type stars in short period ($P=3.2-4.6$ days) orbits. However, HATS-26b ($R_p = 1.75R_J$, $P = 3.3024$ days) and HATS-27b ($R_p=1.50R_J…
We report the discovery of five new transiting hot Jupiter planets discovered by the HATSouth survey: HATS-31b through HATS-35b. These planets orbit moderately bright stars with V magnitudes within the range 11.9-14.4mag while the planets span a range of masses 0.88-1.22MJ, and have somewhat inflated radii between 1.23-1.64RJ.These planets can be classified as typical hot Jupiters, with HATS-31b and HATS-35b being moderately inflated gas giant planets with radii of $1.64 \pm 0.22$ RJ and 1.464+0.069-0.044RJ, respectively, that can be used to constrain inflation mechanisms. All five systems pre…
We report the discovery by the HATSouth project of 5 new transiting hot Jupiters (HATS-54b through HATS-58Ab). HATS-54b, HATS-55b and HATS-58Ab are prototypical short period ($P = 2.5-4.2$ days, $R_p\sim1.1-1.2$ $R_J$) hot-Jupiters that span effective temperatures from 1350 K to 1750 K, putting them in the proposed region of maximum radius inflation efficiency. The HATS-58 system is composed of two stars, HATS-58A and HATS-58B, which are detected thanks to Gaia DR2 data and which we account for in the joint modelling of the available data --- with this, we are led to conclude that the hot jupi…
We report the discovery of HATS-13b and HATS-14b, two hot-Jupiter transiting planets discovered by the HATSouth survey. The host stars are quite similar to each other (HATS-13: V = 13.9 mag, M* = 0.96 Msun, R* = 0.89 Rsun, Teff = 5500 K, [Fe/H] = 0.05; HATS-14: V = 13.8 mag, M* = 0.97 Msun, R* = 0.93 Rsun, Teff = 5350 K, [Fe/H] = 0.33) and both the planets orbit around them with a period of roughly 3 days and a separation of roughly 0.04 au. However, even though they are irradiated in a similar way, the physical characteristics of the two planets are very different. HATS-13b, with a mass of Mp…
We have measured the alignment between the orbit of HATS-3b (a recently discovered, slightly inflated Hot Jupiter) and the spin-axis of its host star. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The sky-projected spin-orbit angle of $λ= 3\pm25^{\circ}$ was determined from spectroscopic measurements of Rossiter-McLaughlin effect. This is the first exoplanet discovered through the HATSouth transit survey to have its spin-orbit angle measured. Our results indicate that the orbi…
Most hot Jupiter exoplanets do not have a nearby planetary companion in their planetary system. One remarkable exception is the system of WASP-47 with an inner and outer nearby companion to a hot Jupiter, providing detailed constrains on its formation history. In this work, we follow-up on a tentative photometric signal of a transiting inner companion to the hot Jupiter HATS-50b. If confirmed, it would be the third case of a hot Jupiter with an inner companion. 63 hours of new ground-based photometry were employed to rule out this signal to about 96% confidence. The injection of artificial tra…
We report the discovery of four close-in transiting exoplanets, HATS-50 through HATS-53, discovered using the HATSouth three-continent network of homogeneous and automated telescopes. These new exoplanets belong to the class of hot Jupiters and orbit G-type dwarf stars, with brightness in the range V=12.5-14.0 mag. While HATS-53 has many physical characteristics similar to the Sun, the other three stars appear to be metal rich, larger and more massive. Three of the new exoplanets, namely HATS-50, HATS-51 and HATS-53, have low density and similar orbital period. Instead, HATS-52 is more dense a…
We present the most complete emission spectrum for inflated hot Jupiter HAT-P-41b combining new HST WFC/G141 spectrum from the Hubble Panchromatic Comparative Exoplanet Treasury (PanCET) program with archival Spitzer eclipse observations. We found a near blackbody-like emission spectrum which is best fitted with an isothermal temperature-pressure (TP) profile that agrees well with the dayside heat redistribution scenario assuming zero Bond albedo. The non-inverted TP profile is consistent with the non-detection of NUV/optical absorbers in the transit spectra. We do not find any evidence for si…
We report the discovery of a new transiting extrasolar planet, HAT-P-55b. The planet orbits a V = 13.207 +/- 0.039 sun-like star with a mass of 1.013 +/- 0.037 solar masses, a radius of 1.011 +/- 0.036 solar radii and a metallicity of -0.03 +/- 0.08. The planet itself is a typical hot Jupiter with a period of 3.5852467 +/- 0.0000064 days, a mass of 0.582 +/- 0.056 Jupiter masses and a radius of 1.182 +/- 0.055 Jupiter radii. This discovery adds to the increasing sample of transiting planets with measured bulk densities, which is needed to put constraints on models of planetary structure and fo…
We report the results of new transit observations for the three hot Jupiter-like planets HATP-36b, HATP-56b and WASP-52b respectively. Transit timing variations (TTVs) are presented for these systems based on observations that span the period 2016 - 2020. The data were collected with the 0.6 m telescope at Adiyaman University (ADYU60, Turkey) and the 1.0 m telescope at TÜBİTAK National Observatory (TUG, Turkey). Global fits were performed to the combined light curves for each system along with the corresponding radial velocity (RV) data taken from the literature. The extracted parameters (for …
We report the discovery of three new transiting extrasolar planets orbiting moderately bright (V=11.1 to 12.4) F stars. The planets have periods of P = 2.6940 d to 4.4572 d, masses of 0.60 M_J to 0.80 M_J, and radii of 1.57 R_J to 1.73 R_J. They orbit stars with masses between 1.40 M_sun and 1.51 M_sun. The three planets are members of an emerging population of highly inflated Jupiters with 0.4 M_J < M < 1.5 M_J and R > 1.5 R_J.
In this paper we report spectroscopy of the transiting hot Jupiter HAT-P-1b. The HAT-P-1b is a giant ($R = 1.2 RJ$), low-mean density transiting extrasolar planet in a visual binary system, composed of two sun-like stars. The host star HAT-P-1b known as ADS 16402 B is a G0V C dwarf (V = 9.87). We revealed optical emission of $C_{2}$, $CN$ and $CH$ radicals in the spectrum of the hot Jupiter HAT-P-1b. We discovered radial pulsation of the hot Jupiter HAT-P-1b with a period of about 1900 sec.
We report the first discovery of a multi-planetary system by the HATSouth network, HATS-59b,c, a planetary system with an inner transiting hot Jupiter and an outer cold massive giant planet, which was detected via radial velocity. The inner transiting planet, HATS-59b, is on an eccentric orbit with $e = 0.129\pm0.049$, orbiting a $V=13.951\pm0.030$ mag solar-like star ($M_* = 1.038\pm0.039 M_{\odot}$, and $R_* = 1.036\pm0.067 R_{\odot}$) with a period of $5.416077\pm0.000017$ days. The outer companion, HATS-59c is on a circular orbit with $ m \sin i = 12.8\pm1.1 M_\mathrm{J}$, and a period of …
We report a spin-orbit misalignment for the hot-Jupiter HATS-14b, measuring a projected orbital obliquity of |lambda|= 76 -5/+4 deg. HATS-14b orbits a high metallicity, 5400 K G dwarf in a relatively short period orbit of 2.8 days. This obliquity was measured via the Rossiter-McLaughlin effect, obtained with observations from Keck-HIRES. The velocities were extracted using a novel technique, optimised for low signal-to-noise spectra, achieving a high precision of 4 m/s point-to-point scatter. However, we caution that our uncertainties may be underestimated. Due to the low rotational velocity o…
We present Warm Spitzer/IRAC secondary eclipse time series photometry of three short-period transiting exoplanets, HAT-P-3b, HAT-P-4b and HAT-P-12b, in both the available 3.6 and 4.5 micron bands. HAT-P-3b and HAT-P-4b are Jupiter-mass, objects orbiting an early K and an early G dwarf stars, respectively. For HAT-P-3b we find eclipse depths of 0.112%+0.015%-0.030% (3.6 micron) and 0.094%+0.016%-0.009% (4.5 micron). The HAT-P-4b values are 0.142%+0.014%-0.016% (3.6 micron) and 0.122%+0.012%-0.014% (4.5micron). The two planets' photometry is consistent with inefficient heat redistribution from t…
We present the discovery of two transiting exoplanets. HAT-P-28b orbits a V=13.03 G3 dwarf star with a period P = 3.2572 d and has a mass of 0.63 +- 0.04 MJ and a radius of 1.21 + 0.11 -0.08 RJ yielding a mean density of 0.44 +- 0.09 g cm-3. HAT-P-29b orbits a V=11.90 F8 dwarf star with a period P = 5.7232 d and has a mass of 0.78 +0.08 -0.04 MJ and a radius of 1.11 +0.14 -0.08 RJ yielding a mean density of 0.71 +- 0.18 g cm-3. We discuss the properties of these planets in the context of other known transiting planets.
The transit timing variation (TTV) and transmission spectroscopy analyses of the planet HAT-P-37b, which is a hot Jupiter orbiting an G-type star, were performed. Nine new transit light curves are obtained and analysed together with 21 published light curves from the literature. The updated physical parameters of HAT-P-37b are presented. The TTV analyses show a possibility that the system has an additional planet which induced the TTVs amplitude signal of 1.74 $\pm$ 0.17 minutes. If the body is located near the 1:2 mean motion resonance orbit, the sinusoidal TTV signal could be caused by the g…
We report the discovery of two transiting extrasolar planets from the HATSouth survey. HATS-11, a V=14.1 G0-star shows a periodic 12.9 mmag dip in its light curve every 3.6192 days and a radial velocity variation consistent with a Keplerian orbit. HATS-11 has a mass of 1.000 $\pm$ 0.060 M$_{\odot}$, a radius of 1.444 $\pm$ 0.057 M$_{\odot}$ and an effective temperature of 6060 $\pm$ 150 K, while its companion is a 0.85 $\pm$ 0.12 M$_J$, 1.510 $\pm$ 0.078 R$_J$ planet in a circular orbit. HATS-12 shows a periodic 5.1 mmag flux decrease every 3.1428 days and Keplerian RV variations around a V=12…
We present a new optical transmission spectrum of the hot Jupiter HAT-P-1b based on two transits observed with the Double Spectrograph (DBSP) on the Palomar 200-inch (P200) telescope. The DBSP transmission spectrum, covering a wavelength range from 3250 to 10007 Å, is consistent with that observed with the Hubble Space Telescope (HST), but the former has a finer spectral resolution. The DBSP spectrum alone reveals the presence of a pressure broadened line wing for Na, the line cores for both Na and K, and tentative evidence for H$_2$O. We obtain consistent results from the spectral retrieval a…
Hot Jupiters, with atmospheric temperatures T ~ 1000 K, have residual thermal ionization levels sufficient for the interaction of the ions with the planetary magnetic field to result in a sizable magnetic drag on the (neutral) atmospheric winds. We evaluate the magnitude of magnetic drag in a representative three-dimensional atmospheric model of the hot Jupiter HD 209458b and find that it is a plausible mechanism to limit wind speeds in this class of atmospheres. Magnetic drag has a strong geometrical dependence, both meridionally and from the day to the night side (in the upper atmosphere), w…
Wide field surveys for transiting planets are well suited to searching diverse stellar populations, enabling a better understanding of the link between the properties of planets and their parent stars. We report the discovery of HAT-P-69b (TOI 625.01) and HAT-P-70b (TOI 624.01), two new hot Jupiters around A stars from the HATNet survey which have also been observed by the Transiting Exoplanet Survey Satellite (TESS). HAT-P-69b has a mass of 3.58 +0.58/-0.58 MJup and a radius of 1.676 +0.051/-0.033 RJup, residing in a prograde 4.79-day orbit. HAT-P-70b has a radius of 1.87 +0.15/-0.10 RJup and…
Hot Jupiters have proven themselves to be a rich class of exoplanets which test our theories of planetary evolution and atmospheric dynamics under extreme conditions. Here, we present three-dimensional magnetohydrodynamic simulations and analytic results which demonstrate that a dynamo can be maintained in the thin, stably-stratified atmosphere of a hot Jupiter, independent of the presumed deep-seated dynamo. This dynamo is maintained by conductivity variations arising from strong asymmetric heating from the planets' host star. The presence of a dynamo significantly increases the surface magne…
For solar-system objects, ultraviolet spectroscopy has been critical in identifying sources for stratospheric heating and measuring the abundances of a variety of hydrocarbon and sulfur-bearing species, produced via photochemical mechanisms, as well as oxygen and ozone. To date, less than 20 exoplanets have been probed in this critical wavelength range (0.2-0.4 um). Here we use data from Hubble's newly implemented WFC3 UVIS G280 grism to probe the atmosphere of the hot Jupiter HAT-P-41b in the ultraviolet through optical in combination with observations at infrared wavelengths. We analyze and …
We report the discovery of HAT-P-56b by the HATNet survey, an inflated hot Jupiter transiting a bright F type star in Field 0 of NASA's K2 mission. We combine ground-based discovery and follow-up light curves with high precision photometry from K2, as well as ground-based radial velocities from TRES on the FLWO 1.5m telescope to determine the physical properties of this system. HAT-P-56b has a mass of $2.18 M_J$, radius of $1.47 R_J$, and transits its host star on a near-grazing orbit with a period of 2.7908 d. The radius of HAT-P-56b is among the largest known for a planet with $M_p > 2 M_J$.…
We report the discovery of HAT-P-54b, a planet transiting a late K dwarf star in field 0 of the NASA K2 mission. We combine ground-based photometric light curves with radial velocity measurements to determine the physical parameters of the system. HAT-P-54b has a mass of 0.760 $\pm$ 0.032 $M_J$, a radius of 0.944 $\pm$ 0.028 $R_J$, and an orbital period of 3.7998 d. The star has V = 13.505 $\pm$ 0.060, a mass of 0.645 $\pm$ 0.020 $M_{\odot}$, a radius of 0.617 $\pm$ 0.013 $R_{\odot}$, an effective temperature of Teff = 4390 $\pm$ 50K, and a subsolar metallicity of [Fe/H] = -0.127 $\pm$ 0.080. …
We report secondary eclipse photometry of two hot Jupiters, WASP-48b and HAT-P-23b, at 3.6 and 4.5 um taken with the InfraRed Array Camera aboard the Spitzer Space Telescope during the warm Spitzer mission and in the H and Ks bands with the Wide Field IR Camera at the Palomar 200-inch Hale Telescope. WASP-48b and HAT-P-23b are Jupiter-mass and twice Jupiter-mass objects orbiting an old, slightly evolved F star and an early G dwarf star, respectively. In the H, Ks, 3.6 um, and 4.5 um bands, respectively, we measure secondary eclipse depths of 0.047% +/- 0.016%, 0.109% +/- 0.027%, 0.176% +/- 0.0…
We report secondary eclipse photometry of the hot Jupiter HAT-P-32Ab, taken with Hale/WIRC in H and Ks bands and with Spitzer/IRAC at 3.6 and 4.5 micron. We carried out adaptive optics imaging of the planet host star HAT-P-32A and its companion HAT-P-32B in the near-IR and the visible. We clearly resolve the two stars from each other and find a separation of 2.923" +/- 0. 004" and a position angle 110.64 deg +/- 0.12 deg. We measure the flux ratios of the binary in g' r' i' z' and H & Ks bands, and determine Teff = 3565 +/- 82 K for the companion star, corresponding to an M1.5 dwarf. We use PH…
We report the discovery by the HATSouth survey of HATS-3b, a transiting extrasolar planet orbiting a V=12.4 F-dwarf star. HATS-3b has a period of P = 3.5479d, mass of Mp = 1.07MJ, and radius of Rp = 1.38RJ. Given the radius of the planet, the brightness of the host star, and the stellar rotational velocity (vsini = 9.0km/s), this system will make an interesting target for future observations to measure the Rossiter-McLaughlin effect and determine its spin-orbit alignment. We detail the low/medium-resolution reconnaissance spectroscopy that we are now using to deal with large numbers of transit…
HAT-P-13b is a Jupiter-mass transiting exoplanet that has settled onto a stable, short-period, and mildly eccentric orbit as a consequence of the action of tidal dissipation and perturbations from a second, highly eccentric, outer companion. Due to the special orbital configuration of the HAT-P-13 system, the magnitude of HAT-P-13b's eccentricity ($e_b$) is in part dictated by its Love number ($k_{2_b}$), which is in turn a proxy for the degree of central mass concentration in its interior. Thus, the measurement of $e_b$ constrains $k_{2_b}$ and allows us to place otherwise elusive constraints…
We report the discovery and characterization of four transiting exoplanets by the HATNet survey. The planet HAT-P-50b has a mass of 1.35 M_J and a radius of 1.29 R_J, and orbits a bright (V = 11.8 mag) M = 1.27 M_sun, R = 1.70 R_sun star every P = 3.1220 days. The planet HAT-P-51b has a mass of 0.31 M_J and a radius of 1.29 R_J, and orbits a V = 13.4 mag, M = 0.98 M_sun, R = 1.04 R_sun star with a period of P = 4.2180 days. The planet HAT-P-52b has a mass of 0.82 M_J and a radius of 1.01 R_J, and orbits a V = 14.1 mag, M = 0.89 M_sun, R = 0.89 R_sun star with a period of P = 2.7536 days. The p…
We report the discovery by the HATSouth survey of HATS-4b, an extrasolar planet transiting a V=13.46 mag G star. HATS-4b has a period of P = 2.5167 d, mass of Mp = 1.32 Mj, radius of Rp = 1.02 Rj and density of rho_p = 1.55 +- 0.16 g/cm^3 ~ 1.24 rhoj. The host star has a mass of 1.00 Msun, a radius of 0.92 Rsun and a very high metallicity [Fe/H]= 0.43 +- 0.08. HATS-4b is among the densest known planets with masses between 1-2 Mj and is thus likely to have a significant content of heavy elements of the order of 75 Mearth. In this paper we present the data reduction, radial velocity measurement …
We present a new ground-based visible transmission spectrum of the high-gravity, hot Jupiter HAT-P-23b, obtained as part of the ACCESS project. We derive the spectrum from five transits observed between 2016 and 2018, with combined wavelength coverage between 5200 Å - 9269 Å in 200 Å bins, and with a median precision of 247 ppm per bin. HAT-P-23b's relatively high surface gravity (g ~ 30 m/s^2), combined with updated stellar and planetary parameters from Gaia DR2, gives a 5-scale-height signal of 384 ppm for a hydrogen-dominated atmosphere. Bayesian models favor a clear atmosphere for the plan…
Global Circulation Models (GCMs) of atmospheric flows are now routinely used to interpret observational data on Hot Jupiters. Localized "equatorial $β$-plane" simulations by Fromang et al. (2016) have revealed that a barotropic (horizontal shear) instability of the equatorial jet appears at horizontal resolutions beyond those typically achieved in global models; this instability could limit wind speeds and lead to increased atmospheric variability. To address this possibility, we adapt the computationally efficient, pseudo-spectral PlaSim GCM, originally designed for Earth studies, to model Ho…
The hot-Jupiter HAT-P-2b has become a prime target for Spitzer Space Telescope observations aimed at understanding the atmospheric response of exoplanets on highly eccentric orbits. Here we present a suite of three-dimensional atmospheric circulation models for HAT-P-2b that investigate the effects of assumed atmospheric composition and rotation rate on global scale winds and thermal patterns. We compare and contrast atmospheric models for HAT-P-2b, which assume one and five times solar metallicity, both with and without TiO/VO as atmospheric constituents. Additionally we compare models that a…
We report the discovery of HAT-P-31b, a transiting exoplanet orbiting the V=11.660 dwarf star GSC 2099-00908. HAT-P-31b is the first HAT planet discovered without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the HATNet project. The 2.17 Mj, 1.1Rj planet has a period P = 5.0054 days and maintains an unusually high eccentricity of e = 0.2450+/-0.0045, determined through Keck, FIES and Subaru high precision radial velocities. Detailed modeling of the radial velocities indicates an additional quadratic residual trend in the data detected to very high confi…
Hot Jupiters are the most studied and easily detectable exoplanets for transit observations.However, the correlation between the atmospheric flow and the emission spectra of such planets is still not understood. Due to huge day-night temperature contrast in hot Jupiter, the thermal redistribution through atmospheric circulation has a significant impact on the vertical temperature-pressure structure and on the emission spectra. In the present work, we aim to study the variation of the temperature-pressure profiles and the emission spectra of such planets due to different amounts of atmospheric …
We present a new optical transmission spectrum of the hot Jupiter HAT-P-32Ab acquired with the Carnegie Observatories Spectrograph and Multiobject Imaging Camera (COSMIC) on the Palomar 200 inch Hale Telescope (P200). The P200/COSMIC transmission spectrum, covering a wavelength range of 3990--9390 Å, is composed of 25 spectrophotometric bins with widths ranging from 200 to 400 Åand consistent with previous transit measurements obtained in the common wavelength range. We derive a combined optical transmission spectrum based on measurements from five independent instruments, which, along with th…
Secondary eclipse observations of several of the hottest hot Jupiters show featureless, blackbody-like spectra or molecular emission features, which are consistent with thermal inversions being present in those atmospheres. Theory predicts a transition between warmer atmospheres with thermal inversions and cooler atmospheres without inversions, but the exact transition point is unknown. In order to further investigate this issue, we observed two secondary eclipses of the hot Jupiter HAT-P-7b with the Hubble Space Telescope (HST) WFC3 instrument and combined these data with previous Spitzer and…
We present a consistent optimal estimation retrieval analysis of ten hot Jupiter exoplanets, each with transmission spectral data spanning the visible to near-infrared wavelength range. Using the NEMESIS radiative transfer and retrieval tool, we calculate a range of possible atmospheric states for WASP-6b, WASP-12b, WASP-17b, WASP-19b, WASP-31b, WASP-39b, HD 189733b, HD 209458b, HAT-P-1b and HAT-P-12b. We find that the spectra of all ten planets are consistent with the presence of some atmospheric aerosol; WASP-6b, WASP-12b, WASP-17b, WASP-19b, HD 189733b and HAT-P-12b are all fit best by Rayl…
We report the discovery of four transiting extrasolar planets (HAT-P-34b - HAT-P-37b) with masses ranging from 1.05 to 3.33 MJ and periods from 1.33 to 5.45 days. These planets orbit relatively bright F and G dwarf stars (from V = 10.16 to V = 13.2). Of particular interest is HAT-P-34b which is moderately massive (3.33 MJ), has a high eccentricity of e = 0.441 +/- 0.032 at P = 5.4526540+/-0.000016 d period, and shows hints of an outer component. The other three planets have properties that are typical of hot Jupiters.
First identified from the HATNet wide-field photometric survey, these candidate transiting planets were then followed-up with a variety of photometric observations. Determining the planetary nature of the objects and characterizing the parameters of the systems were mainly done with the SOPHIE spectrograph at the 1.93m telescope at OHP and the TRES spectrograph at the 1.5m telescope at FLWO. HAT-P-42b and HAT-P-43b are typical hot Jupiters on circular orbits around early-G/late-F main sequence host stars, with periods of 4.641876\pm0.000032 and 3.332688\pm0.000016 days, masses of 0.975\pm0.126…
Time-series spectrophotometric studies of exoplanets during transit using ground-based facilities are a promising approach to characterize their atmospheric compositions. We aim to investigate the transit spectrum of the hot Jupiter HAT-P-1b. We compare our results to those obtained at similar wavelengths by previous space-based observations. We observed two transits of HAT-P-1b with the Gemini Multi-Object Spectrograph (GMOS) instrument on the Gemini North telescope using two instrument modes covering the 320 - 800 nm and 520 - 950 nm wavelength ranges. We used time-series spectrophotometry t…
Because of their activity, late-type stars are known to host powerful flares producing intense high-energy radiation on short time-scales that may significantly affect the atmosphere of nearby planets. We employ a one-dimensional aeronomic model to study the reaction of the upper atmosphere of the hot Jupiter HD 209458b to the additional high-energy irradiation caused by a stellar flare. Atmospheric absorption of the additional energy produced during a flare leads to local atmospheric heating, accompanied by the formation of two propagating shock waves. We present estimates of the additional a…
We report the discovery by the HATNet survey of three new transiting extrasolar planets orbiting moderately bright (V=13.2, 12.8 and 11.9) stars. The planets have orbital periods of 4.3012, 3.1290, and 4.4631 days, masses of 0.39, 0.89, and 0.49 Mjup, and radii of 1.28, 1.43, and 1.28 Rjup. The stellar hosts have masses of 0.94, 1.26, and 1.28 Msun. Each system shows significant systematic variations in its residual radial velocities indicating the possible presence of additional components. Based on its Bayesian evidence, the preferred model for HAT-P-44 consists of two planets, including the…
Hot Jupiter atmospheres exhibit fast, weakly-ionized winds. The interaction of these winds with the planetary magnetic field generates drag on the winds and leads to ohmic dissipation of the induced electric currents. We study the magnitude of ohmic dissipation in representative, three-dimensional atmospheric circulation models of the hot Jupiter HD 209458b. We find that ohmic dissipation can reach or exceed 1% of the stellar insolation power in the deepest atmospheric layers, in models with and without dragged winds. Such power, dissipated in the deep atmosphere, appears sufficient to slow do…
High resolution spectroscopy has opened the way for new, detailed study of exoplanet atmospheres. There is evidence that this technique can be sensitive to the complex, three-dimensional (3D) atmospheric structure of these planets. In this work, we perform cross correlation analysis on high resolution (R~100,000) CRIRES/VLT emission spectra of the Hot Jupiter HD 209458b. We generate template emission spectra from a 3D atmospheric circulation model of the planet, accounting for temperature structure and atmospheric motions---winds and planetary rotation---missed by spectra calculated from one-d…
The study of exoplanet atmospheres showed large diversity compared to the planets in our solar system. Especially Jupiter type exoplanets orbiting their host star in close orbits, the so-called hot and ultra-hot Jupiters, have been studied in detail due to their enhanced atmospheric signature. Due to their tidally locked status, the temperature difference between the day- and nightside triggers atmospheric winds which can lead to various fingerprints in the observations. Spatially resolved absorption lines during transit such as sodium (Na) could be a good tracer for such winds. Different work…
Observations of 43 complete transits of the hot Jupiter exoplanet HAT-P-32b using the MicroObservatory 0.15-m robotic telescope network covering a period of 7 years are presented. Compared with the most recent ephemeris for the system, the precision of the mid-transit times yielded a root-mean-square value from the predicted model of 3.0 min. The estimated system parameters based on EXOFAST modelling are broadly consistent with those of the default parameter values listed in the NASA Exoplanet Archive. An updated orbital period of 2.15000815 +/- 0.00000013 d and ephemeris of 2458881.71392 +/- …
Atmospheric mass-loss from Hot-jupiters can be large due to the close proximity of these planets to their host star and the strong radiation the planetary atmosphere receives. On Earth, a major contribution to the acceleration of atmospheric ions comes from the vertical separation of ions and electrons, and the generation of the ambipolar electric field. This process, known as the "polar wind", is responsible for the transport of ionospheric constituents to the Earth's magnetosphere, where they are well observed. The polar wind can also be enhanced by a relatively small fraction of super-therm…
We report the discovery by the ground-based HATNet survey of the transiting exoplanet HAT-P-68b, which has a mass of 0.724 $\pm$ 0.043 $M_{Jup}$, and radius of 1.072 $\pm$ 0.012 $R_{Jup}$. The planet is in a circular P = 2.2984-day orbit around a moderately bright V = 13.937 $\pm$ 0.030 magnitude K dwarf star of mass 0.673 $+$ 0.020 $-$0.014 $M_{\odot}$, and radius 0.6726 $\pm$ 0.0069 $R_{\odot}$. The planetary nature of this system is confirmed through follow-up transit photometry obtained with the FLWO~1.2m telescope, high-precision RVs measured using Keck-I/HIRES, FLWO~1.5m/TRES, and OHP~1.…
We report the discovery of HAT-P-24b, a transiting extrasolar planet orbiting the moderately bright V=11.818 F8 dwarf star GSC 0774-01441, with a period P = 3.3552464 +/- 0.0000071 d, transit epoch Tc = 2455216.97669 +/- 0.00024 (BJD_UTC), and transit duration 3.653 +/- 0.025 hours. The host star has a mass of 1.191 +/- 0.042 Msun, radius of 1.317 +/- 0.068 Rsun, effective temperature 6373 +/- 80 K, and a low metallicity of [Fe/H] = -0.16 +/- 0.08. The planetary companion has a mass of 0.681 +/- 0.031 MJ, and radius of 1.243 +/- 0.072 RJ yielding a mean density of 0.439 +/- 0.069 g cm-3 . By r…
We report the discovery of three new hot Jupiters with the Next Generation Transit Survey (NGTS) as well as updated parameters for HATS-54b, which was independently discovered by NGTS. NGTS-23b, NGTS-24b and NGTS-25b have orbital periods of 4.076, 3.468, and 2.823 days and orbit G-, F- and K-type stars, respectively. NGTS-24 and HATS-54 appear close to transitioning off the main-sequence (if they are not already doing so), and therefore are interesting targets given the observed lack of Hot Jupiters around sub-giant stars. By considering the host star luminosities and the planets' small orbita…
