Longitudinally Resolved Phase-curve Retrievals of WASP-43b

2021 ◽  
Author(s):  
Patricio E. Cubillos ◽  
Dylan Keating ◽  
Nicolas Cowan ◽  
Johanna Vos ◽  
Ben Burningham ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Phase Curve ◽  
Night Temperature ◽  
Vertical Temperature ◽  
Linear Combinations ◽  
Phase Measurements ◽  
Thermal Phase ◽  
Longitudinal Variations ◽  
Phase Variations ◽  
The Impact

<p>Thermal phase variations of exoplanets are a patent testimony of their multidimensional nature: day-to-night temperature contrasts range from hundreds to thousands of degrees.  Nonetheless, the spectra of these planets have typically been fit using 1D retrieval codes that only account for vertical temperature gradients.  Recent multi-dimensional retrieval schemes are generally based on linear combinations of 1D models, which are more liable to degeneracies and more computationally demanding.  Here we present an alternative: phase-dependent spectral observations are inverted to produce longitudinally resolved spectra that can then be fitted using standard 1D spectral retrieval codes. We test this scheme on the phase-resolved spectra of WASP-43b and on simulated JWST observations using the open-source Pyrat Bay retrieval framework.  We show that 1D spectral retrievals on longitudinally resolved spectra are more accurate than applying 1D spectral retrieval codes to disk-integrated emission spectra, highlighting the impact of longitudinal variations in composition in addition to temperature.  In particular, we find that JWST phase measurements of WASP-43b should be treated with longitudinally resolved spectral retrieval.</p>

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 Linking the Climate and Thermal Phase Curve of 55 Cancri e

2017 ◽  
Vol 849 (2) ◽  
pp. 152 ◽  
Author(s):  
Mark Hammond ◽  
Raymond T. Pierrehumbert
Keyword(s):  
Phase Curve ◽  
Thermal Phase

scholarly journals DEUFRABASE: A Simple Tool for the Evaluation of the Noise Impact of Pavements in Typical Road Geometries

Environments ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Michel Bérengier ◽  
Judicaël Picaut ◽  
Bettina Pahl ◽  
Denis Duhamel ◽  
Benoit Gauvreau ◽  
...  
Keyword(s):  
Traffic Noise ◽  
Emission Spectra ◽  
Low Noise ◽  
Noise Emission ◽  
Simple Method ◽  
Acceptable Error ◽  
The Road ◽  
Noise Impact ◽  
On The Road ◽  
The Impact

Traffic noise is considered by people as one of the most important sources of environmental discomfort. A way to limit the traffic noise is to reduce the noise emission, for example, by using specific low noise pavements, particularly in suburban areas. However, in real situations, it can be difficult to evaluate the impact of a given pavement, because it depends, for example, on the road geometry, the meteorological conditions, or the distance of the receiver position. Finally it can be difficult to select the most appropriate pavement for a given noise reduction objective. In this paper, a simple method is proposed to evaluate the noise impact of a pavement, in typical road geometries and environmental conditions. The proposed approach uses two databases, the first one based on measurements of emission spectra of road vehicles on several typical pavements, the second one made of pre-calculations of noise propagation for typical road configurations. Finally, the method is implemented in an interactive web tool, called DEUFRABASE, which allows one to obtain a fast estimation of the L Aeq (1 h or 24 h) and L den noise levels for various pavements and road configurations, as functions of the traffic flow and composition. By comparing the method with measurements, it is showed that the tool, although based on a restricted number of pavements and on several simplifications, can predict the noise impact of typical road configurations, with an acceptable error, most often less than 2 dB.

The impact of time-dependent stellar activity on the atmospheric chemistry and observability of exoplanets

2021 ◽  
Author(s):  
Amy Louca ◽  
Yamila Miguel ◽  
Shang-Min Tsai
Keyword(s):  
Atmospheric Chemistry ◽  
Emission Spectra ◽  
Time Dependent ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Stellar Spectrum ◽  
Stellar Spectra ◽  
Chemical Tracers ◽  
Atmospheric Escape ◽  
The Impact

<p class="p1">Observations of exoplanets used to characterize the chemistry and dynamics of atmospheres have developed considerably throughout the years. Nonetheless, it remains a difficult task to give a full and detailed description using solely observations. With future space missions such as JWST and ARIEL, both expected to be launched within this decade, it becomes even more crucial to be able to fully explain and predict the underlying chemistry and physics involved. In this research, we focus on modeling star-planet interactions by using synthetic flare spectra to predict chemical tracers for future missions. We make use of a chemical kinetics code that includes synthetic time-dependent stellar spectra and thermal atmospheric escape to simulate the atmospheres of known exoplanets. Using a radiative transfer model we then retrieve emission spectra. This ongoing study is focused on various known planetary systems of which the stellar spectrum has been obtained by the (mega-)MUSCLES collaboration. Preliminary results on these systems show that stellar flares and thermal escape can have a significant effect on the chemistry in atmospheres. </p>

Exploring the convection in super-Earths: Comparing LHS 3844b with 55 Cnc e

2021 ◽  
Author(s):  
Tobias G. Meier ◽  
Dan J. Bower ◽  
Tim Lichtenberg ◽  
Paul J. Tackley ◽  
Brice-Olivier Demory
Keyword(s):  
Surface Temperature ◽  
Mantle Convection ◽  
The Other ◽  
Phase Curve ◽  
Mantle Flow ◽  
Perovskite Layer ◽  
Tectonic Regime ◽  
Thermal Phase ◽  
Temperature Contrast ◽  
Heating Mode

<p>The vigour and style of mantle convection in tidally-locked super-Earths may be substantially different from Earth's regime where the surface temperature is spatially uniform and sufficiently cold to drive downwellings into the mantle. The thermal phase curve for super-Earth LHS 3844b suggests a solid surface and lack of a substantial atmosphere. The dayside temperature is around 1040 K and the nightside temperature is around 0 K, which is unlike any temperature contrast observed at present day for planets in the Solar System. On the other hand, the thermal phase curve of super-Earth 55 Cnc e suggests much hotter temperatures with a nightside temperature around 1380 K and a substellar point temperature around 2700 K. Both super-Earths have therefore temperature contrasts between the day- and nightside of more than 1000 K and we infer that this may also lead to a dichotomy of the interior mantle flow. <br>We run geodynamic simulations of the interior mantle flow using the mantle convection code StagYY. The models are fully compressible with an Arrhenius-type viscosity law where the mantle is modelled with an upper mantle, a perovskite-layer and a post-perovskite layer. The lithospheric strength is modelled through a plastic yielding criteria and the heating mode is either basal heating only or mixed heating (basal and internal heating). For LHS 3844b we find that the surface temperature dichotomy can lead to a hemispheric tectonic regime depending on the strength of the lithosphere and the heating mode in the mantle. In a hemispheric tectonic regime, downwellings occur preferentially on one side and upwellings rise on the other side. We compare these results to the case of 55 Cnc e, where large parts of the surface could be molten. At first order we expect that a magma ocean could homogenise the temperatures on the planet's surface and therefore reduce the likelihood of hemispheric tectonics operating on 55 Cnc e.<br>For LHS 3844b, the contribution of the interior flux to the thermal phase curve is on the order of 15-30 K, and therefore below the detecting capabilities of current and near-future observations. However, for hemispheric tectonics, upwellings might lead to preferential melt generation and outgassing on one hemisphere that could manifest as a secondary signal in phase curve observations. Such signals could also be produced on hotter planets such as 55 Cnc e where parts of the surface are hot enough to melt.</p>

Synthesis and luminescent properties of La1−xNdxP5O14 nanocrystals

2014 ◽  
Vol 16 (33) ◽  
pp. 18004-18009 ◽  
Author(s):  
L. Marciniak ◽  
W. Strek ◽  
Y. Guyot ◽  
D. Hreniak
Keyword(s):  
Dopant Concentration ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Spectroscopic Properties ◽  
Branching Ratios ◽  
Luminescence Decay ◽  
The Impact

The impact of dopant concentration on spectroscopic properties of La1−xNdxP5O12 nanocrystals: the luminescence decay profiles – (a); emission spectra – (b); and luminescence branching ratios – (c).

scholarly journals THERMAL PHASE VARIATIONS OF WASP-12b: DEFYING PREDICTIONS

2012 ◽  
Vol 747 (1) ◽  
pp. 82 ◽  
Author(s):  
Nicolas B. Cowan ◽  
Pavel Machalek ◽  
Bryce Croll ◽  
Louis M. Shekhtman ◽  
Adam Burrows ◽  
...  
Keyword(s):  
Thermal Phase ◽  
Phase Variations

scholarly journals Socioeconomic deprivation scores as predictors of variations in NHS practice payments: a longitudinal study of English general practices 2013–2017

2019 ◽  
Vol 69 (685) ◽  
pp. e546-e554 ◽  
Author(s):  
Louis S Levene ◽  
Richard Baker ◽  
John Bankart ◽  
Nicola Walker ◽  
Andrew Wilson
Keyword(s):  
Intraclass Correlation ◽  
Large Sample Size ◽  
Cross Sectional ◽  
Independent Variables ◽  
Practice Population ◽  
Longitudinal Variations ◽  
General Practices ◽  
Organisational Factors ◽  
The Impact ◽  
Index Of Multiple Deprivation

BackgroundA previous study found that variables related to population health needs were poor predictors of cross-sectional variations in practice payments.AimTo investigate whether deprivation scores predicted variations in the increase over time of total payments to general practices per patient, after adjustment for potential confounders.Design and settingLongitudinal multilevel model for 2013–2017; 6900 practices (84.4% of English practices).MethodPractices were excluded if total adjusted payments per patient were <£10 or >£500 per patient or if deprivation scores were missing. Main outcome measures were adjusted total NHS payments; calculated by dividing total NHS payments, after deductions and premises payments, by the number of registered patients in each practice. A total of 17 independent variables relating to practice population and organisational factors were included in the model after checking for collinearity.ResultsAfter adjustment for confounders and the logarithmic transformation of the dependent and main independent variables (due to extremely skewed [positive] distribution of payments), practice deprivation scores predicted very weakly longitudinal variations in total payments’ slopes. For each 10% increase in the Index of Multiple Deprivation score, practice payments increased by only 0.06%. The large sample size probably explains why eight of the 17 confounders were significant predictors, but with very small coefficients. Most of the variability was at practice level (intraclass correlation = 0.81).ConclusionThe existing NHS practice payment formula has demonstrated very little redistributive potential and is unlikely to substantially narrow funding gaps between practices with differing workloads caused by the impact of deprivation.

scholarly journals 2.5D retrieval of atmospheric properties from exoplanet phase curves: application to WASP-43b observations

2020 ◽  
Vol 493 (1) ◽  
pp. 106-125 ◽  
Author(s):  
Patrick G J Irwin ◽  
Vivien Parmentier ◽  
Jake Taylor ◽  
Jo Barstow ◽  
Suzanne Aigrain ◽  
...  
Keyword(s):  
Temperature Profile ◽  
Water Vapour ◽  
Mole Fraction ◽  
Phase Curve ◽  
Vertical Temperature ◽  
Vertical Temperature Profile ◽  
Retrieval Technique ◽  
The Mean ◽  
Synthetic Phase ◽  
Model Phase

ABSTRACT We present a novel retrieval technique that attempts to model phase curve observations of exoplanets more realistically and reliably, which we call the 2.5-dimensional (2.5D) approach. In our 2.5D approach we retrieve the vertical temperature profile and mean gaseous abundance of a planet at all longitudes and latitudes simultaneously, assuming that the temperature or composition, x, at a particular longitude and latitude (Λ, Φ) is given by $x(\Lambda ,\Phi) = \bar{x} + (x(\Lambda ,0) - \bar{x})\cos ^n\Phi$, where $\bar{x}$ is the mean of the morning and evening terminator values of x(Λ, 0), and n is an assumed coefficient. We compare our new 2.5D scheme with the more traditional 1D approach, which assumes the same temperature profile and gaseous abundances at all points on the visible disc of a planet for each individual phase observation, using a set of synthetic phase curves generated from a GCM-based simulation. We find that our 2.5D model fits these data more realistically than the 1D approach, confining the hotter regions of the planet more closely to the dayside. We then apply both models to WASP-43b phase curve observations of HST/WFC3 and Spitzer/IRAC. We find that the dayside of WASP-43b is apparently much hotter than the nightside and show that this could be explained by the presence of a thick cloud on the nightside with a cloud top at pressure &lt;0.2 bar. We further show that while the mole fraction of water vapour is reasonably well constrained to (1–10) × 10−4, the abundance of CO is very difficult to constrain with these data since it is degenerate with temperature and prone to possible systematic radiometric differences between the HST/WFC3 and Spitzer/IRAC observations. Hence, it is difficult to reliably constrain C/O.

Exoplanet pollution in transit spectroscopy with the next-generation of infrared space telescopes

2020 ◽  
Author(s):  
Giuseppe Morello ◽  
Tiziano Zingales ◽  
Marine Martin-Lagarde ◽  
Rene Gastaud ◽  
Christophe Cossou ◽  
...  
Keyword(s):  
Thermal Emission ◽  
Phase Curve ◽  
Next Generation ◽  
Space Telescopes ◽  
System Parameters ◽  
James Webb Space Telescope ◽  
Infrared Wavelengths ◽  
In Transit ◽  
The Impact

&lt;p&gt;The next generation of space telescopes is expected to deliver transmission spectra of exoplanet atmospheres with precision down to 10 parts per million (ppm). Therefore, it is required to model the astrophysical signals with even greater precision in order not to introduce significant biases for the characterization of the planet and its atmosphere.&lt;/p&gt; &lt;p&gt;We discuss, in particular, the contribution of the planetary flux in the analysis of transit observations. Usually, the planetary flux is assumed to be a negligible fraction of the stellar flux, so called &lt;em&gt;dark planet&lt;/em&gt; hypothesis. However, this hypothesis is not always valid, especially at the infrared wavelengths, around the peak of thermal emission from the planet. We identify two effects, named &lt;em&gt;self-blend&lt;/em&gt; and &lt;em&gt;phase-blend&lt;/em&gt;, that tend to bias the measured transit depth in opposite directions (the &lt;em&gt;self-blend&lt;/em&gt; effect was already known from Kipping &amp; Tinetti 2010).&lt;/p&gt; &lt;p&gt;We introduce a novel sub-package of the software ExoTETHyS that can be used to estimate the amplitude of these two effects depending on the exoplanet system parameters, along with the derivation of the mathematical formulae. In this way, it is possible to identify some priority targets to observe longer transit windows, the secondary eclipse and/or the full phase-curve in order to reduce these potential biases.&lt;/p&gt; &lt;p&gt;We also show the impact of the &lt;em&gt;self-&lt;/em&gt; and &lt;em&gt;phase-blend&lt;/em&gt; effects in the analysis of simulated transit spectra taken with the James Webb Space Telescope (JWST), including the results of the atmospheric retrievals. Our analysis takes into account the possible mitigation depending on the alternative data detrending methods.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt;

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