Transit searches have uncovered Earth-size planets orbiting so close to their host star that their surface should be molten, so-called lava planets. We present idealized simulations of the atmosphere of lava planet K2-141b and calculate the return flow of material via circulation in the magma ocean. We then compare how pure Na, SiO, or SiO$_2$ atmospheres would impact future observations. The more volatile Na atmosphere is thickest followed by SiO and SiO$_2$, as expected. Despite its low vapour pressure, we find that a SiO$_2$ atmosphere is easier to observe via transit spectroscopy due to its greater scale height near the day-night terminator and the planetary radial velocity and acceleration are very high, facilitating high dispersion spectroscopy. The special geometry that arises from very small orbits allows for a wide range of limb observations for K2-141b. After determining the magma ocean depth, we infer that the ocean circulation required for SiO steady-state flow is only $10^{-4}$ m/s while the equivalent return flow for Na is several orders of magnitude greater. This suggests that a steady-state Na atmosphere cannot be sustained and that the surface will evolve over time.
Lava planets have non-global, condensible atmospheres similar to icy bodies within the solar system. Because they depend on interior dynamics, studying the atmospheres of lava planets can lead to understanding unique geological processes driven by their extreme environment. Models of lava planet atmospheres have thus far focused on either radiative transfer or hydrodynamics. In this study, we couple the two processes by introducing ultraviolet and infrared radiation to a turbulent boundary layer model. We also test the effect of different vertical temperature profiles on atmospheric dynamics. …
Sensitivity of Dry Lava Planet Atmospheric Emission Spectra to Changes in Lava Compositions
Leiden Observatory, Leiden University（莱顿天文台，莱顿大学）；Department of Earth Sciences, Vrije Universiteit Amsterdam（地球科学系，阿姆斯特丹自由大学）；Astrophysics Research Institute, Liverpool John Moores University（天体物理研究所，利物浦约翰摩尔斯大学）；SRON Netherlands Institute for Space Research（荷兰空间研究研究所）；Center for Astrophysics, Harvard & Smithsonian（天体物理中心，哈佛大学与史密森尼学会）
Lava worlds belong to a class of short orbital period planets reaching dayside temperatures high enough to melt their silicate crust. Theory predicts that the resulting lava oceans outgas their volatile components, attaining equilibrium with the overlying vapour. This creates a tenuous, silicate-rich atmosphere that may be confined to the permanent dayside of the planet. The launch of JWST will provide the much needed sensitivity and spectral coverage to characterise these worlds. In this paper, we assess the observability of characterisable spectral features by self-consistently modelling sil…
JWST MIRI reveals a potential atmosphere on the ultra-hot rocky planet TOI-431b
University of Maryland（马里兰大学）；University of Chicago（芝加哥大学）；Instituto de Astrofísica de Andalucía (IAA-CSIC)（安达卢西亚天体物理研究所）；University of Birmingham（伯明翰大学）；Carnegie Science（卡内基科学研究所）；Space Telescope Science Institute（太空望远镜科学研究所）；Peking University（北京大学）
Astronomers have discovered a handful of exoplanets with rocky bulk compositions but orbiting so close to their host star that the surface of the planet must be at least partially molten. It is expected that the dayside of such "lava planets" harbors a rock vapor atmosphere that flows quickly towards the airless nightside -- this partial atmosphere is critical to the interpretation of lava planet observations, but transports negligible heat towards the nightside. As a result, the surface temperature of the magma ocean may range from 3000~K near the sub-stellar point down to 1500~K near the day…
Three-Dimensional Ocean Dynamics and Detectability of Tidally Locked Lava Worlds
Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交大李政道研究所）；Department of Earth, Atmosphere and Planetary Science, MIT（麻省理工学院地球、大气与行星科学系）；Peking University（北京大学）；School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）；State Key Laboratory of Dark Matter Physics, Shanghai Jiao Tong University（上海交通大学暗物质物理全国重点实验室）
The magma ocean concept was first conceived to explain the geology of the Moon, but hemispherical or global oceans of silicate melt could be a widespread "lava world" phase of rocky planet accretion, and could persist on planets on short-period orbits around other stars. The formation and crystallization of magma oceans could be a defining stage in the assembly of a core, origin of a crust, initiation of tectonics, and formation of an atmosphere. The last decade has seen significant advances in our understanding of this phenomenon through analysis of terrestrial and extraterrestrial samples, p…
Hot super Earths are exoplanets with short orbital periods ($<$ 10 days), heated by their host stars to temperatures high enough for their rocky surfaces to become molten. A few hot super Earths exhibit high geometric albedos ($>$ 0.4) in the Kepler band (420-900 nm). We are motivated to determine whether reflection from molten lava and quenched glasses (a product of rapidly cooled lava) on the surfaces of hot super Earths contributes to the observationally inferred high geometric albedos. We experimentally measure reflection from rough and smooth textured quenched glasses of both basalt and f…
The Kepler mission has made an important observation, the first detection of photons from a terrestrial planet by observing its phase curve (Kepler-10b). This opens a new field in exoplanet science: the possibility to get information about the atmosphere and surface of rocky planets, objects of prime interest. In this letter, we apply the Lava-ocean model to interpret the observed phase curve. The model, a planet with no atmosphere and a surface partially made of molten rocks, has been proposed for planets of the class of CoRoT-7b, i.e. rocky planets very close to their star (at few stellar ra…
Surface modification on Jupiter's volcanically active moon, Io, has to date been attributed almost exclusively to lava emplacement and volcanic plume deposits. Here we demonstrate that wind-blown transport of sediment may also be altering the Ionian surface. Specifically, shallow subsurface interactions between lava and Io's widespread sulfur dioxide (SO$_2$) frost can produce localized sublimation vapor flows with sufficient gas densities to enable particle saltation. We calculate anticipated outgassing velocities from lava-SO$_2$ frost interactions, and compare these to the saltation thresho…
Evidence for an Atmosphere on the Ultra-Short Period super-Earth HD 3167 b
University of Chicago（芝加哥大学）；University of Maryland, College Park（马里兰大学帕克分校）；Center for Astrophysics | Harvard & Smithsonian（哈佛与史密森尼天体物理中心）；University of Birmingham（伯明翰大学）
A striking feature of the atmosphere of Titan is that no heavy noble gases other than argon were detected by the Gas Chromatograph Mass Spectrometer (GCMS) aboard the Huygens probe during its descent to Titan's surface in January 2005. Here we provide an explanation of the mysterious absence or rarity of these noble gases in Titan's atmosphere: the thermodynamic conditions prevailing at the surface-atmosphere interface of the satellite allow the formation of multiple guest clathrates that preferentially store some species, including all heavy noble gases, over others. The clean water ice neede…
Evolutionary pathways toward survival of a thick CO2- or SO2-rich atmosphere on the lava world TOI-561 b
Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡佩恩天文研究所）；Earth and Planets Laboratory, Carnegie Institution for Science（卡内基科学机构地球与行星实验室）；The Observatories of the Carnegie Institution for Science（卡内基科学机构天文台）；Institute of Astronomy, University of Cambridge（剑桥大学天文学研究所）；School of Physics & Astronomy, University of Birmingham（伯明翰大学物理与天文学院）；Waterloo Centre for Astrophysics and Department of Physics and Astronomy, University of Waterloo（滑铁卢大学天体物理学中心及物理与天文学系）
Many of the confirmed short period super-Earths and smaller sub-Neptunes are sufficiently irradiated for the surface silicates to be sustained in a long-lasting molten state. While there is no direct evidence of magma ocean influence on exoplanets, theory suggests that due to outgassing and diverse evolution paths, a wide range of resulting atmospheric compositions should be possible. Atmospheric contamination caused by the outgassing of the underlying magma ocean is potentially detectable using low resolution spectroscopy. The James Webb Space Telescope provides the necessary spectral coverag…
An Evolving Cosmic Shoreline and Sandbar Bounding the Rocky Airless Valley
Stanford University（斯坦福大学）；The University of Chicago（芝加哥大学）；University of California, San Diego（加州大学圣地亚哥分校）；University of Hawai‘i（夏威夷大学）；University of California, Santa Cruz（加州大学圣克鲁兹分校）；University of Maryland, College Park（马里兰大学帕克分校）
Since its discovery in the aurorae of Jupiter ~30 years ago, the H$_{3}^{+}$ ion has served as an invaluable probe of giant planet upper atmospheres. However, the vast majority of monitoring of planetary H$_{3}^{+}$ radiation has followed from observations that rely on deriving parameters from column-integrated paths through the emitting layer. Here, we investigate the effects of density and temperature gradients along such paths on the measured H$_{3}^{+}$ spectrum and its resulting interpretation. In a non-isothermal atmosphere, H$_{3}^{+}$ column densities retrieved from such observations a…
Thermal Evolution of Lava Planets Across System Ages: Predictions for Hell of a Survey
Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；Waterloo Centre for Astrophysics and Department of Physics and Astronomy, University of Waterloo（滑铁卢大学天体物理中心及物理与天文学系）；School of Physics and Astronomy, University of Birmingham（伯明翰大学物理与天文学院）；Center for Star and Planet Formation, Globe Institute, University of Copenhagen（哥本哈根大学全球研究所恒星与行星形成中心）；Space Telescope Science Institute（太空望远镜科学研究所）；Department of Physics, University of Warwick（华威大学物理系）；Department of Physics and Astronomy, York University（约克大学物理与天文学系）；Trottier Space Institute, McGill University（麦吉尔大学特罗蒂尔空间研究所）
[Abridged] This review paper discussed which chemical effects may be at play in a planet-forming disk midplane, which effects are relevant under different conditions, and which tools are available for modelling chemical kinetics in a disk midplane. The review goes on to discuss some important efforts in the planet formation modelling community to treat chemical evolution, and, vice versa, efforts in the chemical modelling community to implement more physical effects related to planet formation into the chemical modelling. The aim of this review is both to outline some concepts related to plane…
Super-Earths with solid surfaces such CoRot-7b and Kepler-10b are expected to be extremely hot. It has been suggested that they must be atmosphere-free and that a lava ocean is present on their hot dayside. Here, we use several dedicated thermal models to study how observations with NIRSPEC on the JWST could further confirm and constrain, or reject the atmosphere-free lava ocean planet model for very hot super-Earths. Using CoRoT-7b as a working case, we explore the consequences on the phase-curve of a non tidal-locked rotation, with/without an atmosphere, and for different values of the albed…
Theoretical arguments and observations suggest that the atmospheres of Brown Dwarfs and planets are very dynamic on chemical and on physical time scales. The modelling of such substellar atmospheres has, hence, been much more demanding than initially anticipated. This Splinter (http://star-www.st-and.ac.uk/~ch80/CS16/MultiDSplinter_CS16.html) has combined new developments in atmosphere modelling, with novel observational techniques, and new challenges arising from planetary and space weather observations.
Three dimensional models that account for chemistry are useful tools to predict the chemical composition of (exo)planet and brown dwarf atmospheres and interpret observations of future telescopes. Recent Juno observations of the NH3 tropospheric distribution in Jupiter also indicate that 3D chemical modelling may be necessary to constrain the deep composition of the giant planets of the Solar System. However, due to the high computational cost of chemistry calculations, 3D chemical modelling has so far been limited. A solution to include chemical kinetics in a 3D model is to use a reduced chem…
This brief review focuses on methods and applications of modeling exoplanetary atmospheres. We discuss various kinds of state of the art self-consistent and retrieval models in 1D and multi-D with a focus on open questions and short- and long-term goals in the field. Expertise previously developed in modeling cool stellar atmospheres and in modeling solar system planetary atmospheres has proven valuable to the field, and will continue to do so. We described upcoming opportunities for making progress in our understanding of atmospheres, and close with what we see as the field's challenges.
The distribution of a pure condensible planetary atmosphere in equilibrium with a surface reservoir is revisited employing the energy budget of the climate system, emphasizing the atmospheric horizontal latent heat transport. This configuration is applicable to icy Solar System bodies such as Triton as well as a range of possible exoplanet atmospheres, including water or $\mathrm{CO_2}$ iceballs or ocean worlds, and lava planets with mineral vapor atmospheres. Climate regimes for slowly rotating planets with the hot-spot near the substellar point, and for rapidly rotating planets with a warm e…
Chemical compositions of exoplanets can provide key insights into their physical processes, and formation and evolutionary histories. Atmospheric spectroscopy provides a direct avenue to probe exoplanetary compositions. However, whether obtained in transit or thermal emission, spectroscopic observations probe limited pressure windows of planetary atmospheres and are directly sensitive to only a limited set of spectroscopically active species. It is therefore critical to have chemical models that can relate retrieved atmospheric compositions to an atmosphere's bulk physical and chemical state. …
The search for rocky exoplanets plays an important role in our quest for extra-terrestrial life. Here, we discuss the extreme physical properties possible for the first characterized rocky super-Earth, CoRoT-7b (R_pl = 1.58 \pm 0.10 R_Earth, Mpl = 6.9 \pm 1.2 M_Earth). It is extremely close to its star (a = 0.0171 AU = 4.48 R_st), with its spin and orbital rotation likely synchronized. The comparison of its location in the (Mpl, Rpl) plane with the predictions of planetary models for different compositions points to an Earth-like composition, even if the error bars of the measured quantities a…
The atmospheres of brown dwarfs orbiting in close proximity to their parent white dwarf represent some of the most extreme irradiated environments known. Understanding their complex dynamical mechanisms pushes the limits of theoretical and modelling efforts, making them valuable objets to study to test contemporary understanding of irradiated atmospheres. We use the Exo-FMS GCM to simulate the brown dwarfs WD0137-349B, SDSS J141126.20+200911.1B and EPIC212235321B, first coupled to a multi-banded grey radiative-transfer scheme then a spectral correlated-k scheme with high temperature opacity ta…
A general machine learning model of aluminosilicate melt viscosity and its application to the surface properties of dry lava planets
Université Paris Cité（巴黎城市大学）；Institut de physique du globe de Paris（巴黎地球物理研究所）；CNRS-UMR 7154（法国国家科学研究中心-7154联合研究单位）；Institut Universitaire de France（法国大学研究院）；York University（约克大学）；ETH Zürich（苏黎世联邦理工学院）；Institute of Geochemistry and Petrology（地球化学与岩石学研究所）
The escaping atmospheres of hydrogen driven by stellar X-ray and extreme Ultraviolet (XUV) have been detected around some exoplanets by the excess absorption of Ly$α$ in far ultraviolet band. In the optical band the excess absorption of H$α$ is also found by the ground-based instruments. However, it is not certain so far if the escape of the atmosphere driven by XUV can result in such absorption. Here we present the XUV driven hydrodynamic simulation coupled with the calculation of detailed level population and the process of radiative transfer for WASP-121b. Our fiducial model predicts a mass…
The K2-33 planetary system hosts one transiting ~5 R_E planet orbiting the young M-type host star. The planet's mass is still unknown, with an estimated upper limit of 5.4 M_J. The extreme youth of the system (<20 Myr) gives the unprecedented opportunity to study the earliest phases of planetary evolution, at a stage when the planet is exposed to an extremely high level of high-energy radiation emitted by the host star. We perform a series of 1D hydrodynamic simulations of the planet's upper atmosphere considering a range of possible planetary masses, from 2 to 40 M_E, and equilibrium temperat…
Context. Observations suggest that exoplanets such as HD 189733b form clouds in their atmospheres which have a strong feedback onto their thermodynamical and chemical structure, and overall appearance. Aims. Inspired by mineral cloud modelling efforts for Brown Dwarf atmospheres, we present the first spatially varying kinetic cloud model structures for HD 189733b. Methods. We apply a 2-model approach using results from a 3D global radiation-hydrodynamic simulation of the atmosphere as input for a detailed, kinetic cloud formation model. Sampling the 3D global atmosphere structure with 1D traje…
Characterising the atmospheres of exoplanets is key to understanding their nature and provides hints about their formation and evolution. High-resolution measurements of the helium triplet, He(2$^{3}$S), absorption of highly irradiated planets have been recently reported, which provide a new mean to study their atmospheric escape. In this work, we study the escape of the upper atmospheres of HD 189733 b and GJ 3470 b by analysing high-resolution He(2$^{3}$S) absorption measurements and using a 1D hydrodynamic model coupled with a non-LTE model for the He(2$^{3}$S) state. We also use the H dens…
On the basis of geological evidence, it is often stated that the early martian climate was warm enough for liquid water to flow on the surface thanks to the greenhouse effect of a thick atmosphere. We present 3D global climate simulations of the early martian climate performed assuming a faint young sun and a CO2 atmosphere with pressure between 0.1 and 7 bars. The model includes a detailed radiative transfer model using revised CO2 gas collision induced absorption properties, and a parameterisation of the CO2 ice cloud microphysical and radiative properties. A wide range of possible climates …
Aims: ARCiS, a novel code for the analysis of exoplanet transmission and emission spectra is presented. The aim of the modelling framework is to provide a tool able to link observations to physical models of exoplanet atmospheres. Methods: The modelling philosophy chosen in this paper is to use physical and chemical models to constrain certain parameters while keeping free the parts where our physical understanding is still more limited. This approach, in between full physical modelling and full parameterisation, allows us to use the processes we understand well and parameterise those less und…
