scholarly journals Phase curve and variability analysis of WASP-12b using TESS photometry

2021 ◽  
Author(s):  
Niall Owens ◽  
E J W de Mooij ◽  
C A Watson ◽  
M J Hooton
Keyword(s):  
Brightness Temperature ◽  
Phase Curve ◽  
Variability Analysis ◽  
Significant Variability ◽  
Orbital Decay ◽  
Night Side ◽  
Period Model ◽  
Constant Period ◽  
Hot Jupiter

Abstract We analyse Sector 20 TESS photometry of the ultra-hot Jupiter WASP-12b, and extract its phase curve to study the planet’s atmospheric properties. We successfully recover the phase curve with an amplitude of 549 ± 62 ppm, and a secondary eclipse depth of 609$^{+74}_{-73}$ ppm. The peak of the phase curve is shifted by 0.049 ± 0.015 in phase, implying that the brightest spot in the atmosphere is shifted from the substellar point towards the planet’s evening terminator. Assuming zero albedo, the eclipse depth infers a day-side brightness temperature of 3128$^{+64}_{-68}$ K. No significant detection of flux from the night-side is found at 60 ± 97 ppm, implying a night-side brightness temperature of <2529 K (1-σ). We do not detect any significant variability in the light from the planet over the ∼27 days of the TESS observations. Finally, we note that an ephemeris model taking orbital decay into account provides a significantly better fit than a constant-period model.

scholarly journals The ultra-hot-Jupiter KELT-16 b: Dynamical Evolution and Atmospheric Properties

2021 ◽  
Author(s):  
L Mancini ◽  
J Southworth ◽  
L Naponiello ◽  
Ö Baştürk ◽  
D Barbato ◽  
...  
Keyword(s):  
Lower Limit ◽  
Broad Band ◽  
Flux Ratio ◽  
Dynamical Evolution ◽  
Emission Spectra ◽  
Temperature Inversion ◽  
Period Change ◽  
Phase Curve ◽  
Night Side ◽  
Hot Jupiter

Abstract We present broad-band photometry of 30 planetary transits of the ultra-hot Jupiter KELT-16 b, using five medium-class telescopes. The transits were monitored through standard B, V, R, I filters and four were simultaneously observed from different places, for a total of 36 new light curves. We used these new photometric data and those from the TESS space telescope to review the main physical properties of the KELT-16 planetary system. Our results agree with previous measurements but are more precise. We estimated the mid-transit times for each of these transits and combined them with others from the literature to obtain 69 epochs, with a time baseline extending over more than four years, and searched for transit time variations. We found no evidence for a period change, suggesting a lower limit for orbital decay at 8 Myr, with a lower limit on the reduced tidal quality factor of $Q^{\prime }_{\star }>(1.9 \pm 0.8) \times 10^5$ with $95\%$ confidence. We built up an observational, low-resolution transmission spectrum of the planet, finding evidence of the presence of optical absorbers, although with a low significance. Using TESS data, we reconstructed the phase curve finding that KELT-16 b has a phase offset of 25.25 ± 14.03 ○E, a day- and night-side brightness temperature of 3190 ± 61 K and 2668 ± 56 K, respectively. Finally, we compared the flux ratio of the planet over its star at the TESS and Spitzer wavelengths with theoretical emission spectra, finding evidence of a temperature inversion in the planet’s atmosphere, the chemical composition of which is preferably oxygen-rich rather than carbon-rich.

scholarly journals Characterizing the Atmospheres of Hot Jupiters: From Spectra to Multi-Color Maps

2008 ◽  
Vol 4 (S253) ◽  
pp. 255-261
Author(s):  
Heather A. Knutson
Keyword(s):  
Emission Spectrum ◽  
Inversion Layer ◽  
Emission Spectra ◽  
Phase Curve ◽  
Hot Jupiters ◽  
Thermal Phase ◽  
Additional Support ◽  
Temperature Inversions ◽  
The Relationship ◽  
Hot Jupiter

AbstractWe present new observations of the emission spectrum of the hot Jupiter TrES-4 designed to test the theory that the presence of temperature inversions in the atmospheres of these planets are correlated with the amount of radiation received by the planet. Our observations reveal that TrES-4 has an emission spectrum similar to that of HD 209458b, which requires the presence of an inversion layer high in the atmosphere and water emission bands in order to explain the observed features, providing additional support for that theory. We also present new observations of the thermal phase curve of HD 189733b at 24 μm, which we combine with our previous observations at 8 μm to examine how circulation in this planet's atmosphere varies as a function of depth. We discuss the relationship between the strength of the day-night circulation on both planets and their other observable properties, in particular their emission spectra.

scholarly journals The influence of eclipses in the stellar radio emission

2016 ◽  
Vol 12 (S328) ◽  
pp. 305-307
Author(s):  
Caius Lucius Selhorst ◽  
Adriana Valio
Keyword(s):  
Active Region ◽  
Radio Emission ◽  
Light Curve ◽  
Brightness Temperature ◽  
Quadratic Function ◽  
Stellar Radius ◽  
Optical Light Curve ◽  
Hot Jupiter

AbstractHere we simulate the shape of a planetary transit observed at radio wavelengths. The simulations use a light curve of the K4 star HAT-P-11 and its hot Jupiter companion as proxy. From the HAT-P-11 optical light curve, a prominent spot was identified (1.10 RP and 0.6 IC). On the radio regime, the limb brighting of 30% was simulated by a quadratic function, and the active region was assumed to have the same size of the optical spot. Considering that the planet size is 6.35% of the the stellar radius, for the quiet star regions the transit depth is smaller than 0.5%, however, this value can increase to ~2% when covering an active region with 5.0 times the quiet star brightness temperature.

scholarly journals Thermal Phase Curves of XO-3b: An Eccentric Hot Jupiter at the Deuterium Burning Limit

2021 ◽  
Vol 163 (1) ◽  
pp. 32
Author(s):  
Lisa Dang ◽  
Taylor J. Bell ◽  
Nicolas B. Cowan ◽  
Daniel Thorngren ◽  
Tiffany Kataria ◽  
...  
Keyword(s):  
Energy Balance ◽  
Wind Speed ◽  
Mixed Layer ◽  
Energy Balance Model ◽  
Phase Curve ◽  
Balance Model ◽  
Model Predictions ◽  
M Phase ◽  
Averaged Model ◽  
Hot Jupiter

Abstract We report Spitzer full-orbit phase observations of the eccentric hot Jupiter XO-3b at 3.6 and 4.5 μm. Our new eclipse depth measurements of 1770 ± 180 ppm at 3.6 μm and 1610 ± 70 ppm at 4.5 μm show no evidence of the previously reported dayside temperature inversion. We also empirically derive the mass and radius of XO-3b and its host star using Gaia DR3's parallax measurement and find a planetary mass M p = 11.79 ± 0.98 M Jup and radius R p = 1.295 ± 0.066 R Jup. We compare our Spitzer observations with multiple atmospheric models to constrain the radiative and advective properties of XO-3b. While the decorrelated 4.5 μm observations are pristine, the 3.6 μm phase curve remains polluted with detector systematics due to larger amplitude intrapixel sensitivity variations in this channel. We focus our analysis on the more reliable 4.5 μm phase curve and fit an energy balance model with solid body rotation to estimate the zonal wind speed and the pressure of the bottom of the mixed layer. Our energy balance model fit suggests an eastward equatorial wind speed of 3.13 − 0.83 + 0.26 km s−1, an atmospheric mixed layer down to 2.40 − 0.16 + 0.92 bars, and a Bond albedo of 0.106 − 0.106 + 0.008 . We assume that the wind speed and mixed layer depth are constant throughout the orbit. We compare our observations with 1D planet-averaged model predictions at apoapse and periapse and 3D general circulation model predictions for XO-3b. We also investigate the inflated radius of XO-3b and find that it would require an unusually large amount of internal heating to explain the observed planetary radius.

scholarly journals THE 4.5 μm FULL-ORBIT PHASE CURVE OF THE HOT JUPITER HD 209458b

2014 ◽  
Vol 790 (1) ◽  
pp. 53 ◽  
Author(s):  
Robert T. Zellem ◽  
Nikole K. Lewis ◽  
Heather A. Knutson ◽  
Caitlin A. Griffith ◽  
Adam P. Showman ◽  
...  
Keyword(s):  
Phase Curve ◽  
Hot Jupiter

scholarly journals TESS Phase Curve of the Hot Jupiter WASP-19b

2020 ◽  
Vol 159 (3) ◽  
pp. 104 ◽  
Author(s):  
Ian Wong ◽  
Björn Benneke ◽  
Avi Shporer ◽  
Tara Fetherolf ◽  
Stephen R. Kane ◽  
...  
Keyword(s):  
Phase Curve ◽  
Hot Jupiter

scholarly journals Spitzer secondary eclipses of Qatar-1b

2018 ◽  
Vol 610 ◽  
pp. A55 ◽  
Author(s):  
Emily Garhart ◽  
Drake Deming ◽  
Avi Mandell ◽  
Heather Knutson ◽  
Jonathan J. Fortney
Keyword(s):  
Brightness Temperature ◽  
Circular Orbit ◽  
Model Atmosphere ◽  
Orbital Eccentricity ◽  
Eclipse Observations ◽  
Hot Jupiter

Aims. Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks band suggest that it may have an unusually high day side temperature, indicative of minimal heat redistribution. There have also been indications that the orbit may be slightly eccentric, possibly forced by another planet in the system. We investigate the day side temperature and orbital eccentricity using secondary eclipse observations with Spitzer. Methods. We observed the secondary eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 μm wavelengths. We used pixel-level decorrelation to correct for Spitzer’s intra-pixel sensitivity variations and thereby obtain accurate eclipse depths and central phases. Results. Our 3.6 μm eclipse depth is 0.149 ± 0.051% and the 4.5 μm depth is 0.273 ± 0.049%. Fitting a blackbody planet to our data and two recent Ks band eclipse depths indicates a brightness temperature of 1506 ± 71 K. Comparison to model atmospheres for the planet indicates that its degree of longitudinal heat redistribution is intermediate between fully uniform and day-side only. The day side temperature of the planet is unlikely to be as high (1885 K) as indicated by the ground-based eclipses in the Ks band, unless the planet’s emergent spectrum deviates strongly from model atmosphere predictions. The average central phase for our Spitzer eclipses is 0.4984 ± 0.0017, yielding e cos ω = −0.0028 ± 0.0027. Our results are consistent with a circular orbit, and we constrain e cos ω much more strongly than has been possible with previous observations.

scholarly journals Formation of hot Jupiters through secular chaos and dynamical tides

2019 ◽  
Vol 486 (2) ◽  
pp. 2265-2280 ◽  
Author(s):  
Jean Teyssandier ◽  
Dong Lai ◽  
Michelle Vick
Keyword(s):  
Semimajor Axis ◽  
Giant Planet ◽  
Giant Planets ◽  
Orbital Energy ◽  
High Eccentricity ◽  
Hot Jupiters ◽  
Orbital Decay ◽  
Short Period ◽  
Orbital Periods ◽  
Hot Jupiter

Abstract The population of giant planets on short-period orbits can potentially be explained by some flavours of high-eccentricity migration. In this paper, we investigate one such mechanism involving ‘secular chaos’, in which secular interactions between at least three giant planets push the inner planet to a highly eccentric orbit, followed by tidal circularization and orbital decay. In addition to the equilibrium tidal friction, we incorporate dissipation due to dynamical tides that are excited inside the giant planet. Using the method of Gaussian rings to account for planet–planet interactions, we explore the conditions for extreme eccentricity excitation via secular chaos and the properties of hot Jupiters formed in this migration channel. Our calculations show that once the inner planet reaches a sufficiently large eccentricity, dynamical tides quickly dissipate the orbital energy, producing an eccentric warm Jupiter, which then decays in semimajor axis through equilibrium tides to become a hot Jupiter. Dynamical tides help the planet avoid tidal disruption, increasing the chance of forming a hot Jupiter, although not all planets survive the process. We find that the final orbital periods generally lie in the range of 2–3 d, somewhat shorter than those of the observed hot Jupiter population. We couple the planet migration to the stellar spin evolution to predict the final spin-orbit misalignments. The distribution of the misalignment angles we obtain shows a lack of retrograde orbits compared to observations. Our results suggest that high-eccentricity migration via secular chaos can only account for a fraction of the observed hot Jupiter population.

scholarly journals Understanding the atmospheric properties and chemical composition of the ultra-hot Jupiter HAT-P-7b

2019 ◽  
Vol 631 ◽  
pp. A79 ◽  
Author(s):  
Ch. Helling ◽  
N. Iro ◽  
L. Corrales ◽  
D. Samra ◽  
K. Ohno ◽  
...  
Keyword(s):  
Gas Phase ◽  
Local Equilibrium ◽  
Theoretical Models ◽  
Cloud Formation ◽  
Phase Curve ◽  
Large Temperature ◽  
Global Changes ◽  
Hot Jupiters ◽  
Dependent Observations ◽  
Hot Jupiter

Context. Of the presently known ≈3900 exoplanets, sparse spectral observations are available for ≈100. Ultra-hot Jupiters have recently attracted interest from observers and theoreticians alike, as they provide observationally accessible test cases. Confronting detailed theoretical models with observations is of preeminent importance in preparation for upcoming space-based telescopes. Aims. We aim to study cloud formation on the ultra-hot Jupiter HAT-P-7b, the resulting composition of the local gas phase, and how their global changes affect wavelength-dependent observations utilised to derive fundamental properties of the planet. Methods. We apply a hierarchical modelling approach as a virtual laboratory to study cloud formation and gas-phase chemistry. We utilise 97 vertical 1D profiles of a 3D GCM for HAT-P-7b to evaluate our kinetic cloud formation model consistently with the local equilibrium gas-phase composition. We use maps and slice views to provide a global understanding of the cloud and gas chemistry. Results. The day/night temperature difference on HAT-P-7b (ΔT ≈ 2500 K) causes clouds to form on the nightside (dominated by H2/He) while the dayside (dominated by H/He) retains cloud-free equatorial regions. The cloud particles vary in composition and size throughout the vertical extension of the cloud, but also globally. TiO2[s]/Al2O3[s]/CaTiO3[s]-particles of cm-sized radii occur in the higher dayside-latitudes, resulting in a dayside dominated by gas-phase opacity. The opacity on the nightside, however, is dominated by 0.01…0.1μm particles made of a material mix dominated by silicates. The gas pressure at which the atmosphere becomes optically thick is ~10−4 bar in cloudy regions, and ~0.1 bar in cloud-free regions. Conclusions. HAT-P-7b features strong morning/evening terminator asymmetries, providing an example of patchy clouds and azimuthally-inhomogeneous chemistry. Variable terminator properties may be accessible by ingress/egress transmission photometry (e.g., CHEOPS and PLATO) or spectroscopy. The large temperature differences of ≈2500 K result in an increasing geometrical extension from the night- to the dayside. The H2O abundance at the terminator changes by <1 dex with altitude and ≲0.3 dex (a factor of 2) across the terminator for a given pressure, indicating that H2O abundances derived from transmission spectra can be representative of the well-mixed metallicity at P ≳ 10 bar. We suggest the atmospheric C/O as an important tool to trace the presence and location of clouds in exoplanet atmospheres. The atmospheric C/O can be sub- and supersolar due to cloud formation. Phase curve variability of HAT-P-7b is unlikely to be caused by dayside clouds.

scholarly journals Transit timing variations in the WASP-4 planetary system

2019 ◽  
Vol 490 (3) ◽  
pp. 4230-4236 ◽  
Author(s):  
John Southworth ◽  
M Dominik ◽  
U G Jørgensen ◽  
M I Andersen ◽  
V Bozza ◽  
...  
Keyword(s):  
Planetary System ◽  
Planetary Systems ◽  
Time Effect ◽  
High Confidence ◽  
Stellar Activity ◽  
The Third ◽  
Orbital Decay ◽  
Systemic Velocity ◽  
Rule Out ◽  
Hot Jupiter

ABSTRACT Transits in the planetary system WASP-4 were recently found to occur 80 s earlier than expected in observations from the TESS satellite. We present 22 new times of mid-transit that confirm the existence of transit timing variations, and are well fitted by a quadratic ephemeris with period decay dP/dt = −9.2 ± 1.1 ms yr−1. We rule out instrumental issues, stellar activity, and the Applegate mechanism as possible causes. The light-time effect is also not favoured due to the non-detection of changes in the systemic velocity. Orbital decay and apsidal precession are plausible but unproven. WASP-4 b is only the third hot Jupiter known to show transit timing variations to high confidence. We discuss a variety of observations of this and other planetary systems that would be useful in improving our understanding of WASP-4 in particular and orbital decay in general.

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