New models of Jupiter in the context of Juno and Galileo: signature of a decoupling between the atmosphere and the interior

2020 ◽  
Author(s):  
Florian Debras ◽  
Gilles Chabrier

<p><span lang="en-US">Juno's observations of Jupiter's gravity field have revealed extremely low values for the gravitational moments that are difficult to reconcile with the high abundance of metals observed in the atmosphere by Galileo. Recent studies chose to arbitrarily get rid of one of these two constraints in order to build models of Jupiter.</span></p> <p><span lang="en-US">In this presentation, I will detail our new Jupiter structure models reconciling Juno and Galileo observational constraints. These models confirm the need to separate Jupiter into at least 4 layers: an outer convective shell, a non-convective zone of compositional change, an inner convective shell and a diluted core representing about 60 percent of the planet in radius. Compared to other studies, these models propose a new idea with important consequences: a decrease in the quantity of metals between the outer and inner convective shells. This would imply that the atmospheric composition is not representative of the internal composition of the planet, contrary to what is regularly admitted, and would strongly impact the Jupiter formation scenarios (localization, migration, accretion).</span></p> <p><span lang="en-US">In particular, the presence of an internal non-convective zone prevents mixing between the two convective envelopes. I will detail the physical processes of this semi-convective zone (layered convection or H-He immiscibility) and explain how they may persist during the evolution of the planet.</span></p> <p><span lang="en-US">These models also impose a limit mass on the compact core, which cannot be heavier than 5 Earth masses. Such a mass, lower than the runaway gas accretion minimum mass, needs to be explained in the light of our understanding of the formation and evolution of giant planets.</span></p> <p><span lang="en-US">Using these models of Jupiter, I will finally detail the application of our new understanding of the interior of this planet to giant exoplanets. At a time of direct imaging of extrasolar planets and atmospheric characterization of hot Jupiters, a good understanding of the internal processes of planets in the solar system is paramount to make the best use of all the observations.</span></p>

2021 ◽  
Author(s):  
Florian Debras ◽  
Gilles Chabrier

<p>Juno's observations of Jupiter's gravity field have revealed extremely low values for the gravitational moments that are difficult to reconcile with the high abundance of metals observed in the atmosphere by both Galileo and Juno. Recent studies chose to arbitrarily get rid of one of these two constraints in order to build models of Jupiter.</p><p>In this presentation, I will detail our new Jupiter structure models reconciling Juno and Galileo observational constraints. These models confirm the need to separate Jupiter into at least 4 layers: an outer convective shell, a non-convective zone of compositional change, an inner convective shell and a diluted core representing about 60 percent of the planet in radius. Compared to other studies, these models propose a new idea with important consequences: a decrease in the quantity of metals between the outer and inner convective shells. This would imply that the atmospheric composition is not representative of the internal composition of the planet, contrary to what is regularly admitted, and would strongly impact the Jupiter formation scenarios (localization, migration, accretion).</p><p>In particular, the presence of an internal non-convective zone prevents mixing between the two convective envelopes. I will detail the physical processes of this semi-convective zone (layered convection or H-He immiscibility) and explain how they may persist during the evolution of the planet.</p><p>These models also impose a limit mass on the compact core, which cannot be heavier than 5 Earth masses. Such a mass, lower than the runaway gas accretion minimum mass, needs to be explained in the light of our understanding of the formation and evolution of giant planets.</p><p>I will finally detail the application of our work to Saturn, and what we can expect to learn about the interior of the giant planets in the years to come. </p>


2018 ◽  
Vol 612 ◽  
pp. A108 ◽  
Author(s):  
A.-M. Lagrange ◽  
M. Keppler ◽  
N. Meunier ◽  
J. Lannier ◽  
H. Beust ◽  
...  

Context. The search for extrasolar planets has been limited so far to close orbit (typ. ≤5 au) planets around mature solar-type stars on the one hand, and to planets on wide orbits (≥10 au) around young stars on the other hand. To get a better view of the full giant planet population, we have started a survey to search for giant planets around a sample of carefully selected young stars. Aims. This paper aims at exploring the giant planet population around one of our targets, β Pictoris, over a wide range of separations. With a disk and a planet already known, the β Pictoris system is indeed a very precious system for studies of planetary formation and evolution, as well as of planet–disk interactions. Methods. We analyse more than 2000 HARPS high-resolution spectra taken over 13 years as well as NaCo images recorded between 2003 and 2016. We combine these data to compute the detection probabilities of planets throughout the disk, from a fraction of au to a few dozen au. Results. We exclude the presence of planets more massive than 3 MJup closer than 1 au and further than 10 au, with a 90% probability. 15+ MJup companions are excluded throughout the disk except between 3 and 5 au with a 90% probability. In this region, we exclude companions with masses larger than 18 (resp. 30) MJup with probabilities of 60 (resp. 90) %.


2008 ◽  
Vol 4 (S253) ◽  
pp. 552-555
Author(s):  
Daniel Angerhausen ◽  
Alfred Krabbe ◽  
Christof Iserlohe

AbstractTransiting exoplanets provide a unique opportunity for follow up exploration through phase-differential observation of their emission and transmission spectra. From such spectra immediate clues about the atmospheric composition and the planets chemistry can be drawn. Such information is of imminent importance for the theory of the formation of planets in general as well as for their particular evolution. Ground-based spectroscopy of exoplanet transits is a needful extension of results already obtained through space-based observations. We present results of an exploratory study to use near-infrared integral field spectroscopy to observe extrasolar planets. We demonstrate how adaptive optics-assisted integral field spectroscopy compares with other spectroscopic techniques currently applied. An advanced reduction method using elements of a spectral-differential decorrelation method is also discussed. We have tested our concept with a K-Band time series observations of HD209458b and HD189733b obtained with SINFONI at the VLT and OSIRIS at Keck during secondary transits at a spectral resolution of R=3000.


2019 ◽  
Vol 622 ◽  
pp. A71 ◽  
Author(s):  
C. von Essen ◽  
M. Mallonn ◽  
L. Welbanks ◽  
N. Madhusudhan ◽  
A. Pinhas ◽  
...  

There has been increasing progress toward detailed characterization of exoplanetary atmospheres, in both observations and theoretical methods. Improvements in observational facilities and data reduction and analysis techniques are enabling increasingly higher quality spectra, especially from ground-based facilities. The high data quality also necessitates concomitant improvements in models required to interpret such data. In particular, the detection of trace species such as metal oxides has been challenging. Extremely irradiated exoplanets (~3000 K) are expected to show oxides with strong absorption signals in the optical. However, there are only a few hot Jupiters where such signatures have been reported. Here we aim to characterize the atmosphere of the ultra-hot Jupiter WASP-33 b using two primary transits taken 18 orbits apart. Our atmospheric retrieval, performed on the combined data sets, provides initial constraints on the atmospheric composition of WASP-33 b. We report a possible indication of aluminum oxide (AlO) at 3.3-σ significance. The data were obtained with the long slit OSIRIS spectrograph mounted at the 10-m Gran Telescopio Canarias. We cleaned the brightness variations from the light curves produced by stellar pulsations, and we determined the wavelength-dependent variability of the planetary radius caused by the atmospheric absorption of stellar light. A simultaneous fit to the two transit light curves allowed us to refine the transit parameters, and the common wavelength coverage between the two transits served to contrast our results. Future observations with HST as well as other large ground-based facilities will be able to further constrain the atmospheric chemical composition of the planet.


2013 ◽  
Vol 8 (S299) ◽  
pp. 266-270
Author(s):  
Korey Haynes ◽  
Avi M. Mandell ◽  
Evan Sinukoff ◽  
Nikku Madhusudhan ◽  
Adam Burrows ◽  
...  

AbstractWe present analysis of transit spectroscopy of three extrasolar planets, WASP-12 b, WASP-17 b, and WASP-19 b, using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). Measurement of molecular absorption in the atmospheres of these planets offers the chance to explore several outstanding questions regarding the atmospheric structure and composition of these highly irradiated, Jupiter-mass objects. We analyze the data for a single transit for each planet, using a strategy similar in certain aspects to the techniques used by Berta (2012), and achieve almost photon-limited results for individual spectral bins. Our final transit spectra are consistent with the presence of a broad absorption feature at 1.4 μm most likely due to water, but the amplitude of the absorption is less than expected based on previous observations with Spitzer, possibly due to hazes absorbing in the NIR. However, the degeneracy of models with different compositions and temperature structures combined with the low amplitude of any features in the data preclude our ability to place unambiguous constraints on the atmospheric composition without a comprehensive multi-wavelength analysis.


Author(s):  
Thérèse Encrenaz

The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations.


Author(s):  
O. Mousis ◽  
D. H. Atkinson ◽  
R. Ambrosi ◽  
S. Atreya ◽  
D. Banfield ◽  
...  

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.


2014 ◽  
Vol 785 (2) ◽  
pp. 148 ◽  
Author(s):  
Sukrit Ranjan ◽  
David Charbonneau ◽  
Jean-Michel Désert ◽  
Nikku Madhusudhan ◽  
Drake Deming ◽  
...  

2014 ◽  
Vol 9 (S310) ◽  
pp. 194-203 ◽  
Author(s):  
Sean N. Raymond ◽  
Alessandro Morbidelli

AbstractThe “Grand Tack” model proposes that the inner Solar System was sculpted by the giant planets' orbital migration in the gaseous protoplanetary disk. Jupiter first migrated inward then Jupiter and Saturn migrated back outward together. If Jupiter's turnaround or “tack” point was at ~ 1.5 AU the inner disk of terrestrial building blocks would have been truncated at ~ 1 AU, naturally producing the terrestrial planets' masses and spacing. During the gas giants' migration the asteroid belt is severely depleted but repopulated by distinct planetesimal reservoirs that can be associated with the present-day S and C types. The giant planets' orbits are consistent with the later evolution of the outer Solar System.Here we confront common criticisms of the Grand Tack model. We show that some uncertainties remain regarding the Tack mechanism itself; the most critical unknown is the timing and rate of gas accretion onto Saturn and Jupiter. Current isotopic and compositional measurements of Solar System bodies – including the D/H ratios of Saturn's satellites – do not refute the model. We discuss how alternate models for the formation of the terrestrial planets each suffer from an internal inconsistency and/or place a strong and very specific requirement on the properties of the protoplanetary disk.We conclude that the Grand Tack model remains viable and consistent with our current understanding of planet formation. Nonetheless, we encourage additional tests of the Grand Tack as well as the construction of alternate models.


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