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we study the feasibility of measuring the d/h ratio in the atmospheres of exoplanets using current and future telescopes. the deuterium content of the atmosphere can tell us something about the formation and evolution of the exoplanet, but requires detailed consideration of the molecular absorption. | probing atmospheric escape and evolution in exoplanets: the feasibility of measuring d/h in exoplanet atmospheres using current and future observatories |
low-density, transiting exoplanets present outstanding opportunities to study planetary atmospheres due to their relatively large atmospheric scale heights, and large expected absorption features in transmission. in this dissertation talk i will present observations of two of the most rarefied planets known to science ... | helium, water, and carbon on low-density exoplanets |
we constructed 1-d atmospheric semi-empirical models of the m dwarf exoplanet hosts gj 832 (m2), gj 581 (m3), and gj 876 (m5), with the primary goal of synthesizing ultraviolet (uv) spectra of these stars. uv radiation drives photochemical processes in exoplanet atmospheres and can lead to atmospheric escape via hydrod... | semi-empirical modeling of the m dwarf exoplanet hosts gj 832, gj 581, and gj 876: uv radiation and implications for exoplanet atmospheres |
atmosphere escape is observed in the solar system for a variety of objects, including the sun all the way down to pluto. it should, therefore, come as no surprise that planets orbiting other stars may exhibit similar phenomena, providing an opportunity to explore the effects of atmosphere escape across a range of condi... | planetary evaporation through evolution |
planets lose mass over the course of their lives, shaping the observed population. the hubble space telescope has been our premier tool for observing this process in action over the past fifteen years, using uv spectroscopy targeting escaping hydrogen and, more recently, ir spectroscopy targeting escaping helium. we ha... | can dust in outflows obscure exoplanet transmission spectra? |
we simulate the space environment around the planet au microscopii b and the response of the escaping planetary atmospheric to space weather conditions of a time-varying ambient stellar wind and coronal mass ejection (cme). we calculate the lyman alpha line profile and its variations as a result of the space weather co... | space weather-driven variations in lyman alpha absorption signatures of exoplanet atmospheric escape: mhd simulations and the case of au mic b |
the heating by photo-ionization in the thermosphere of short-period exoplanets can drive hydrodynamic escape, which is key to understanding the evolution of the planet atmosphere and explaining the atmospheric measurements. besides powering the atmosphere escape, the energy deposited by euv photons from the host star c... | a hydrodynamic study of radiative cooling and escape of metal species in hot jupiter atmospheres |
in this work the height profiles of temperature, velocity, and density were obtained for the hot neptune gj 436b, using a one-dimensional self-consistent aeronomic model. we traced the expansion of the gas envelope affected by heating from the extreme radiation of the host star from the thin atmospheric layer 1.02r 0 u... | on the thermal atmosphere evaporation of hot neptune gj 436b |
we propose to adapt an existing modeling framework to interpret ultraviolet observations of atmospheric escape in exoplanets, aiming to provide the community with a scalable, open-source code that will be used to understand the evolution of exoplanets at the population level. our motivation lies in that understanding t... | the great escape: a comparative study of photoevaporation in exoplanets observed with hst |
we simulate the space environment around au microscopii b and the interaction between the magnetized stellar wind with a planetary atmospheric outflow for ambient stellar wind conditions and coronal mass ejection (cme) conditions. we also calculate synthetic lyα" role="presentation" tabindex="0">α absorption due to ... | space weather-driven variations in ly-alpha absorption signatures of exoplanet atmospheric escape: mhd simulations and the case of au mic b |
the recently discovered strongly irradiated terrestrial exoplanet lhs3844b presents a first opportunity to understand the impact of the uv environment produced by an m dwarf star on planetary atmospheric escape processes. astronomers were recently awarded 100 hours with spitzer to measure the infrared phase curve of lh... | a first opportunity to test models of atmospheric escape for a terrestrial exoplanet |
lyα (1216 å) and the o i triplet (1302, 1305, and 1306 å) are bright stellar emission lines in the far-ultraviolet (fuv) that trace the stellar chromosphere. lyα in particular is used to predict the flux in other high-energy wavelength regimes and serve as a backlight for probing the atmospheric escape of transiting ex... | recovering stellar lyα and o i emission from hst-cos spectra: separating stellar and geocoronal signals |
hot jupiters are massive gaseous planets which orbit closely to their parent star. the strong stellar irradiation at these small orbital separations causes the temperature of the upper atmosphere of the planet to rise. this can cause the planet's atmosphere to escape into space, creating an exoplanet outflow. we ascert... | the escaping upper atmospheres of hot jupiters |
the helium triplet at 1083 nm has recently emerged as a powerful new observational probe of exoplanet atmospheric loss. we are using this new technique to conduct a survey of atmospheric escape in inflated hot gas giants using the nirspec instrument on the keck ii telescope. here we present the detection of helium in t... | keck/nirspec studies of helium in the atmospheres of two inflated hot gas giants orbiting k dwarfs: wasp-52b and wasp-177b |
recent atmospheric models and observations of transiting exoplanets have shown that metastable helium is an invaluable tracer of their upper atmospheres. ground-based, high-resolution spectrographs are able to resolve the strong absorption line of metastable helium at 10830 angstroms, and probe the morphology and kinem... | what exoplanetary helium can tell us about stellar winds, magnetic fields, and the nature of sub-neptunes |
in other solar systems, the radiation streaming from the central star can have a destructive impact on the atmospheres of the stars close-in planets. a new study suggests that these exoplanets may also have a much harder time keeping their moons.where are the exomoons?moons are more common in our solar system than plan... | the impact of stars on moons |
in exoplanet atmospheres, lyman alpha radiation can ionize atoms, dissociate molecules, and exert pressure forces that drive an outflow. monte carlo simulations of such phenomena have a large computational cost due to the extreme optical depths at lya line center. we present a novel, semi-analytic solution to the radia... | a novel solution to an old problem in lyman alpha radiative transfer |
the super-earth hip116454b was the first exoplanet detected by the k2 mission, in transit across a bright and nearby k1 dwarf (v=10.2, d=55 pc). the low density of the planet suggests it must have at least 30% water or a 0.5% h-he envelope. given the strong xuv irradiation from the young (2 gyr) host star, this h-he en... | search for an evaporating ocean on the super-earth hip 116454b |
ultraviolet transit observations probe the upper atmosphere of exoplanets, where mass loss occurs. our analysis of nuv transmission observations of hd 209458b shows evidence for ionized iron beyond the planet's roche lobe, and no evidence for neutral iron, neutral magnesium, nor ionized magnesium. these results pose a ... | signs of ionized iron beyond the roche lobe of hd 209458b from nuv observations |
currently, active studies on the formation, stability and evolution of exoplanet atmospheres are being conducted through observations by ground and space telescopes, as well as mathematical modeling. shortly after the observation of the extended hydrogen cloud around the exoplanet - transit hot jupiter hd209458b, a num... | on dissipation of the exoplanetary atmospheres |
using a global 3d, fully self-consistent, multi-fluid gas-dynamic aeronomic model, we simulate the dynamically expanding upper atmosphere of an exoplanet hd 209458b. the complex spatial structure of the escaping upper atmospheric planetary material, energized by the stellar xuv and driven further by tidal forces, while... | global 3d multi-fluid aeronomy simulation of the hd 209458b |
one of the proposed explanations for the observed lack of close-in exoplanets with sizes between 1.5 and 2.0 earth-radii is that this valley is carved by atmospheric erosion: sub-neptune-sized planets begin their lives with large h/he-rich envelopes, which are lost during their early ages due to photoevaporation. the r... | far-ultraviolet exploration of nearby young exoplanet-hosting stars |
recent kepler observations revealed hundreds of terrestrial type exoplanets around g to m dwarfs. many of the detected exoplanets are located close to their host stars and are exposed to large fluxes of ionizing radiation. how do exoplanetary atmospheres respond to such harsh stellar environments? this presentation dis... | modeling the upper atmospheres of exoplanets: energy deposition and escape |
induced magnetospheres of non-magnetized atmospheric bodies like mars and venus are formed by magnetic fields of ionospheric currents induced by the convective electric field e = - v x b/c of the solar wind. the induced magnetic fields create a magnetic barrier which forms a void of the solar wind plasma, an induced ma... | degenerate induced magnetospheres |
the heating by photo-ionization in the thermosphere of short-period exoplanets can drive hydrodynamic escape, which is key to understanding the evolution of the planet atmosphere and explaining the atmospheric measurements. besides powering the atmosphere escape, the energy deposited by euv photons from the host star c... | a hydrodynamic study of radiative cooling and escape of metal species in hot jupiter atmospheres |
exoplanets' atmospheres and exospheres have been observed for more than a decade. on the observational side, a large number of atmospheres have been probed. in particular, uv observations have provided detailed information on the physical processes at work in the upper atmospheres and exospheres in various type of exop... | exoplanetary atmospheres under the effects of stellar flares |
exoplanets in extreme irradiation environments, close to their parent stars, could lose some fraction of their atmospheres because of the extreme irradiation. atmospheric mass loss has been observed during the past 12 years for hot gas giants, as large (~10%) ultraviolet absorption signals during transits. meanwhile, n... | a giant cloud of hydrogen escaping the warm neptune-mass planet gj 436b |
to investigate how an intrinsic magnetic field affects atmospheric escape, one has to look at the whole chain, from the precipitation of solar wind particles (and electromagnetic waves) onto the atmosphere, to heating and acceleration of ionospheric ions, to the possible escape of the ions through the magnetosphere. he... | stellar wind energy influx to intrinsic magnetospheres |
radio emission is known to be produced by magnetized solar system planets via the cyclotron maser instability (cmi). it is very probable that this is also true for magnetized exoplanets but radio emission from planets outside the solar system has not been found yet. up to now it was thought that so-called hot jupiters,... | investigation of exoplanetary radio emission - new aspects in the search for exoplanets at radio wavelengths |
the heating by photoionization in the thermosphere of short-period exoplanets can drive hydrodynamic escape, which is key to understanding the evolution of planetary atmospheres and explaining transit observations. besides powering atmospheric escape, the energy deposited by extreme uv photons from the host star can al... | a hydrodynamic study of the escape of metal species and excited hydrogen in the atmosphere of the hot jupiter wasp-121b |
the young magnetically active solar-like stars are efficient generators of ionizing radiation in the form of x-ray and extreme-uv (euv) flux, stellar winds, and eruptive events. the eruptive events include (super)flares with energies 100 times greater than that observed on the sun. these outputs represent the critical ... | living with the young sun: first results of hst-xmm newton and tess coordinated observations of young suns and modeling of their coronae, winds and eruptive events |
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 l... | the impact of time-dependent stellar activity on the atmospheric chemistry and observability of exoplanets |
the d/h ratio is a powerful window into the evolution of atmospheres. atmospheric escape results loss of the lighter isotope, which, in the solar system, has allowed us to conclude that mars and venus lost significant amount of water. measuring the d/h ratio in exoplanet atmospheres is possible by looking at the absorp... | ground and space based observatories: the feasibility of measuring d/h in exoplanet atmospheres |
a lack of close-in neptune-sized planets, and the recently-discoveredbimodal distribution of super-earths and sub-neptunes from kepler, haveboth been interpreted as evidence that exoplanet evolution is profoundlyaffected by xuv- driven atmospheric evaporation. the key uncertainty inthis interpretation is the energetic ... | xuv irradiation of the youngest and nearest transiting super-earths and neptunes |
the recent discovery of a super-earth transiting the bright starhd219134 provides an unprecedented opportunity for detailed study of theatmosphere of low-mass exoplanet. the k3v star is located at a distanceof only 6.5pc, enabling sensitive measurements of its x-ray flux andspectrum. this is important because x-ray/euv... | the x-ray irradiation of the nearest transiting super-earth |
recent observations, especially space telescope missions, reveal that there are many kinds of exoplanets. especially, earth-mass to several earth-mass planets has two types of planets: the bare-rocky planets and planets possessing significant atmosphere. they are divided by the planetary radius since the hydrogen-heliu... | catastrophic atmospheric loss event induced by the giant impact |
hot exoplanets with semi-major axes smaller than 0.05 au can go considerable alteration from the high energy radiation of their host stars radiation from driving winds to altering the thermal profiles to disintegrating nearby planets. a variety of exoplanets are studied in this high irradiation environment with differe... | observations of disintegrating, evaporating and hot planet atmospheres with transmission spectra |
the atmospheres of highly irradiated exoplanets are observed to undergo hydrodynamic escape, resulting in planetary mass loss. however, stellar winds can shape and even prevent atmospheric escape, affecting observable signatures of escape such as lyman-alpha and h-alpha line profiles. in this work, we simulate atmosphe... | effects of stellar winds on spectroscopic transits of close-in exoplanets |
our hst and keck observational campaigns have detected, for thefirst time, escaping atmospheres around multiple young mini-neptunes.photoevaporation from these planets shapes exoplanet demographics,but one of the biggest sources of uncertainty in modelling the outflowis the x-ray and extreme uv spectrum of the star. st... | photoevaporation from small planets orbiting young, active stars (ii) |
planetary thermal escape, the so-called jeans escape, occurs in the uppermost layer of the atmosphere, the exosphere. there, the medium is not collisional enough to maintain the velocity distribution function maxwellian and a part of the gas overcomes the escape velocity. however, there is another mechanism which empha... | how does the stellar lyman alpha flux drive the planetary hydrogen exospheric escape? |
near-uv transit measurements could be used to investigate a variety ofexoplanet phenomena including atmospheric escape, vertical distributionof aerosols, and interactions of the planetary atmosphere with a stellarwind. xmm-newton is one of only three nuv capable space telescopes with aguest observer program, and -- due... | uv transmission spectroscopy of hot jupiter atmospheres with the xmm-newton |
ultra-hot jupiters (uhjs), jovian exoplanets with equilibrium temperatures greater than 2250 k, have quickly become recognized as unique laboratories for understanding the effect of irradiation on planetary atmospheres. to properly understand atmospheric heating and escape on exoplanets, we must observe how exoplanets ... | comparing escaping metals and heat deposition in ultra-hot jupiters |
hydrodynamic atmospheric escape is thought to be the main avenue for early evolution in exoplanets ranging from gas giants to terrestrial worlds, as shown by demographic studies resulting from the kepler survey. however, with only three exoplanets to date that display smoking gun evidence of hydrodynamic escape, most m... | hydrodynamic atmospheric escape in a benchmark ultra-hot jupiter |
the young magnetically active solar-like stars are efficient generators of ionizing radiation in the form of x-ray and extreme uv (euv) flux, stellar wind and eruptive events. these outputs are the critical factors affecting atmospheric escape and chemistry of (exo)planets around active stars. while x-ray fluxes and su... | magnetic life of young suns: data constrained model of the corona and wind from k1 ceti |
photo-evaporation of planetary atmospheres plays a key role in the evolution of exoplanets, carving their whole population. however, direct observations of atmospheric escape are scarce and almost non-existent in the mass range of super-earths and mini-neptunes, while these planets are among the most impacted by the ph... | a comparative study of atmospheric escape in the brightest system of super-earths straddling the evaporation valley |
transmission spectroscopy is one of our most powerful tools for characterizing exoplanet atmospheres, and thanks to the recent launch of nasa's tess mission we will soon have a large sample of planets around bright stars, ideally suited to this technique. with it's unique combination of uv to nir wavelength coverage an... | transmission spectroscopy of exoplanets with luvoir |
hot jupiters (hj) are exoplanets, gas giants with low orbits (≤ 0.1 a.u.). the stellar x-ray and ultraviolet (xuv) radiation energy deposition result in heating ionization and the consequent expansion of planetary atmosphere. expansion of upper atmosphere under certain conditions could be so large that the majority of ... | laboratory simulation of hot jupiters atmosphere expansion |
large-scale exoplanet search surveys have shown evidence that atmospheric escape is a ubiquitous process that shapes the evolution and demographics of planets. however, we lack a detailed understanding of this process because very few exoplanets discovered to date could be probed for signatures of atmospheric escape. r... | search for helium in the upper atmosphere of the hot jupiter wasp-127 b using phoenix/gemini |
the characterization of exoplanet atmospheres will be a major scientific endeavor in the coming decades, in particular the search for biosignatures in the atmospheres of temperate, rocky exoplanets. it is a primary science driver for upcoming space-based (e.g., jwst) and ground-based (e.g., gmt) facilities. there are c... | characterizing exoplanetary atmospheres in the tess era |
observing and understanding potentially habitable exoplanet systems, like trappist-1, is one of the field's top priorities. one challenge to habitability planets orbiting m type stars face is extreme x-ray and ultraviolet (xuv) radiation at the beginning of the system's lifetime. during this time, any water existent on... | bayesian calculations of water inventories and oxygen accumulation on the trappist-1 planets |
the habitability of earth-like planets is an increasingly important subject in astrophysics and in planetary sciences. atmospheric escape plays a vital role in the evolution of the habitability of earth-like planets. by systematically analyzing the numerical simulation results of the interactions between the planetary ... | quantifying the key factors affecting the escape of planetary atmospheres |
we report the detections of photoevaporative atmospheric escape from four young mini neptunes (< 3 r⊕, < 1 gyr), the smallest and youngest planets for which escaping atmospheres have been detected. out of the five we observed, we obtained one detection in ly alpha and three detections in the metastable helium lin... | first detections of escaping atmospheres from young mini neptunes |
in this work we applied the previously developed self-consistent 1d model of hydrogen-helium atmosphere with suprathermal electrons to close-in hot neptune gj 436 b. the obtained height profile of density shows the two-scale structure of the planetary atmosphere. the mass-loss rate is found to be about. | thermal atmospheric escape of close-in exoplanets |
low-mass close-in exoplanets are susceptible to intense atmospheric escape. recent studies suggested that such escaping outflow can deliver abundant aerosols to upper atmospheres and drastically inflate the observed transit radius. here, we investigate how aerosols grow and move in escaping atmospheres and influence tr... | aerosols in escaping atmospheres: implications for transmission spectra and origin of super-puffs |
kelt-9b is the hottest discovered exoplanet to date and ground-based transmission spectroscopy of this ultra-hot jupiter has revealed a wealth of atoms and ions entrapped in its escaping atmosphere. here we present new near-ultraviolet (nuv) observations of the planet obtained with the colorado ultraviolet transit expe... | near-ultraviolet transmission spectroscopy of the ultra-hot jupiter kelt-9b from the colorado ultraviolet transit experiment |
the lyman alpha emission line is the brightest uv emission line in m and k dwarfs and serves as an important tool for studies of stellar chromospheres, the interstellar medium, and exoplanet atmospheres. however, lyman-alpha observations are proven difficult due to the strong obstruction by the interstellar medium (ism... | new and improved lyman-α reconstructions of m & k dwarfs from the muscles treasury survey |
one of the most well-studied exoplanets to date, hd 189733b stands out as an archetypal hot jupiter with a wide collection of observations and theoretical models aimed at characterizing its atmosphere, interior, host star, and environment. we report here on the results of an extensive campaign to observe atmospheric es... | atmospheric escape in hd 189733b: variable signatures of hydrogen, oxygen and carbon measured with hst |
the last couple of years has seen a significant increase in detections of evaporating exoplanets, owing mainly to the discovery of the metastable helium as a probe for atmospheric escape. this process is thought to be an important factor to explain features in the exoplanet population, such as the hot-neptune desert an... | an open-source framework to plan and interpret observations of atmospheric escape in exoplanets |
ultraviolet observations of ultra-hot jupiters (uhjs; teff > 2000 k) provide us with an opportunity to investigate previously unexplored parameters of exoplanet atmospheres. wasp-189b is one of the hottest planets discovered to date with a day side temperature of about 2640 k. it orbits a bright (v = 6.64) a-type st... | near ultraviolet observations of wasp-189b with cute telescope |
hydrodynamic escape from exoplanet atmospheres may be an important evolutionary process for many irradiated gas-rich planets, and could help explain trends in the observed exoplanet population. observational evidence for atmospheric escape has usually come from observations of excess hydrogen ly-α absorption in exoplan... | new insights into the escaping atmospheres of hat-p-11b and wasp-69b: simulated 10830 \\r{a} helium line transmission spectra |
we review atmospheric escape processes from mars as measured by the maven mission, and consider how the martian atmosphere would fare if mars orbited an active m dwarf star. | atmospheric escape from mars: lessons for studies of exoplanets |
the martian atmosphere and climate system will respond as the solar luminosity continues to increase over the next 5 billion years. the mars surface will heat up to above the melting temperature of water ice, even without greenhouse warming. water ice currently in the polar caps and ground ice will melt, potentially re... | mars' atmosphere, volatiles, and climate as the sun heats up over the next 5 billion years |
atmospheric escape is believed to significantly influence the evolution of close-in exoplanets, and has been proposed to shape planetary demographics in the form of the hot neptune desert and evaporation valley. in order to test these theories, it is crucial to obtain accurate estimates of the atmospheric mass-loss rat... | constraining atmospheric mass-loss rates of exoplanets by simulating spectral lines of multiple species |
the rocky planets in our solar system each have their own complicated stories to tell, and we have decades of data observing them up close. yet, looking at the innermost worlds of mercury and venus, we still don't have complete answers to simple questions. how much bigger would mercury need to be, in order for it to ha... | the thermal emission spectrum of the closest m dwarf transiting rocky planet |
atmospheres of close-in exoplanets around k and m dwarfs are subject to large fluxes of ionizing radiation from the hosts stars. first, the stellar radiative flux in the x-ray and extreme uv (xuv) ionizes and heats the upper atmosphere, driving atmospheric heating, affecting the conductance, and enhancing atmospheric e... | studying impact of space weather factors on exoplanetary atmospheric thermodynamics and chemistry with exoplanet-itr tool |
in this talk, i will give an overview of recent key results from ultraviolet studies of cool stars (focusing on the "extreme ultraviolet" bandpass, 10 – 91 nm), with an emphasis on implications for atmospheric escape. i will conclude by presenting the landscape for stellar and exoplanetary investigations utilizing ultr... | ultraviolet spectra of exoplanet host stars as inputs for atmospheric escape calculations |
the lyman alpha emission line is the brightest uv emission line in m and k dwarfs and serves as an important tool for studies of stellar chromospheres, the interstellar medium, and exoplanet atmospheres. however, lyman-alpha observations are proven difficult due to the strong obstruction by the interstellar medium (ism... | new and improved lyman alpha reconstructions of m and k dwarfs |
using the global 3d multi-fluid hd and its extension to mhd we simulated the measured hd209458b transit absorption depths at the fuv lines, and at the nir line (10830 å) of metastable helium hei(23s) triplet, paying attention to possible change of the absorption profiles due to the presence of planetary intrinsic magne... | magnetosphere of hot jupiter hd209458b and transit absorption in lines related to the upper atmosphere |
photo-evaporation of planetary atmospheres plays a key role in the evolution of exoplanets, carving their whole population. however, direct observations of atmospheric escape are scarce and almost non-existent in the mass range of super-earths and mini-neptunes, while these planets are among the most impacted by the ph... | a comparative study of atmospheric escape in the brightest system of super-earths straddling the evaporation valley |
au mic is an m1ve star in the β pic moving group and therefore has an age of 23 ± 3 myr. at 9.79 ± 0.04 pc, it is one of the closest pre-main sequence stars to earth. two exoplanets transiting au mic have been discovered using data from tess. au mic b orbits closer to its host, with a period of 8.46 days. it has a radi... | au mic b, or not au mic b: the question of the young planet's escaping atmosphere |
the escape of hydrogen atoms to space from the upper atmosphere is an important process at mars, responsible for the depletion of much of the planet's initial water. most modern-day hydrogen loss at mars is considered to be via thermal (jeans) escape, in which some atoms in the high-energy tail of a collisional velocit... | hco+ dissociative recombination and other significant drivers of nonthermal hydrogen loss at mars |
photoevaporating planetary winds have been proposed as important mechanism contributing to the evolution of the volatile inventory for close-in planets, potentially explaining the observed radius valley seen in the population of low-mass exoplanets at around r ~ 1.7rearth. molecules originating in a planets' lower atmo... | the c/o ratio and its influence on hydrodynamic escape from super-earth exoplanets |
kepler observations revealed two striking features in the distribution of exoplanet radii: a dearth of short period sub-neptune-sized planets, and a relatively clean gap around 2 earth radii. atmospheric escape of planetary h/he envelopes driven by the high-energy x-ray and uv irradiation from the host star can explain... | estimating the atmospheric mass loss of v1298 tau's four young planets & the role of the host star in planet population studies |
the transition between rocky and volatile/gas-rich planets is one of the main open questions in exoplanetary research. population studies show that this transition is not smooth, but rocky super-earths and gas-rich mini-neptunes with masses within 7-15 earth masses should co-exist. atmospheric escape is surmised to con... | atmospheric escape from a mini-neptune |
ultraviolet transit observations probe the upper atmosphere of exoplanets, where mass loss occurs. our analysis of the archival hst/stis nuv transmission observations of hd 209458b shows evidence for ionized iron, but no evidence for neutral iron, neutral magnesium, nor ionized magnesium. while our non-detection of neu... | revisiting the nuv transmission spectrum of hd 209458b: signs of ionized iron beyond the roche lobe |
the atmospheres of highly irradiated exoplanets are observed to undergo hydrodynamic escape, resulting in planetary mass loss. however, stellar winds can shape and even prevent atmospheric escape, affecting observable signatures of escape such as lyman-α and h-α line profiles. in this work, we simulate atmospheric esca... | leaking exoplanets: understanding how stars affect atmospheric escape in exoplanets |
because of rare collisions, the motion of light species (h, h2) in the planetary exospheres is essentially determined by the external forces: the gravitation from the planet and the radiation pressure, ... currently, the only analytical model used to model exospheric neutral density profiles is the well-known chamberla... | analysis of the effect of the radiation pressure on planetary exospheres : application to earth, mars, titan and hot jupiters |
in recent years, nasa has prioritized the discovery and characterization of habitable exoplanets, including investigating which star-planet systems are conducive to habitable conditions. the escape small explorer mission, currently in phase a development, supports this goal by measuring the euv and fuv spectra of nearb... | america's next top uv spectral model: building an snr calculator for the escape small explorer mission |
this work estimates the effect of the extreme ultraviolet (uv) radiation of the parent star on the production of the suprathermal fraction of atomic hydrogen in the h 2 → h transition region in the upper atmosphere of gj 436b. we also consider the formation of the escaping flux of h atoms created by this effect. we cal... | on non-thermal atmospheric loss for exoplanet gj 436b caused by the h 2 photodissociation input |
the habitability of exoplanets like earth around red dwarfs - a population of stars smaller than the sun, that are 70% of the stars in our galaxy - can be affected by large emissions of energy, called flares, produced by these stars. flares can heat the upper planetary atmosphere and drive the escape of water of these ... | the contribution of m dwarf flares to the thermal escape of potentially habitable planet atmospheres |
the evaporating exoplanets (eve) code allows to model an escaping atmosphere on a transiting exoplanet in three dimensions. with eve we are then able to make predictions on the signatures caused by the absorbing atmosphere, in the observed transmitted stellar spectrum. a key ingredient in our model is the local synthet... | building local stellar spectra from observations: the neutral helium chromospheric lines |
planets transiting m dwarfs offer our best opportunities to observe the atmospheres of potentially habitable planets outside the solar system. models predict that m dwarfs can significantly erode their planets' atmospheres, but no observations yet exist to investigate this atmospheric escape. gj1132b is a warm, rocky, ... | hydrogen escape from a rocky earth-size exoplanet |
atmospheric escape has first been detected through transit observations of massive hot jupiters like hd209458b and hd189733b. absorption signatures in the lyman-alpha line of their host stars have been attributed to comet-like tails of escaping neutral hydrogen, blown away by the stellar radiation pressure or stellar w... | evaporating atmospheres: from hot-jupiters to warm-neptunes |
the key role that hydrodynamic escape has on the mass loss of the planets and their evolution is well known. this is particularly important for close-in planets because the extreme stellar xuv irradiation they receive causes them to undergo hydrodynamic atmospheric escape. although the mass loss caused by this mechanis... | on the study of atmospheric escape of exoplanets using the new window of the he 10830 line |
recent data suggest that most of rocky exoplanets around active g-m planet hosts should be exposed to high ionizing radiation fluxes from stellar coronae, flares, magnetized winds and coronal mass ejections. this raises the question of the atmospheric plasma dynamics and subsequent plasma escape driven by the energy de... | transition from xuv driven ion escape to hydrodynamic escape: implications for habitability of trappist1 b-h and toi-700d rocky exoplanets |
atmospheric escape is an important factor shaping the exoplanet population and hence drives our understanding of planet formation. atmospheric escape from giant planets is driven primarily by the stellar x-ray and extreme-ultraviolet (euv) radiation. euv and longer wavelength uv radiation also power disequilibrium chem... | stellar activity parameter as a proxy for stellar extreme ultraviolet fluxes |
multi-planet systems which display transit timing variations (ttvs) have produced one of the most surprising and impactful results of the kepler mission: the existence of very low-density "puffy" exoplanets. these planets are controversial, since their rate of atmospheric escape according to standard models means they ... | precise stellar characterization as a critical test of ttv mass measurements |
this paper presents an analysis of the influence of the neutral atmosphere state on non-thermal processes in the upper atmosphere of the exoplanet π men c. namely, the contribution of exothermic photochemistry reactions to the formation of the suprathermal atomic hydrogen fraction in the h 2 →h transition region of the... | photochemical losses in the upper atmosphere of exoplanet π men c depending on the state of the neutral atmosphere |
we make use of the one-way coupled framework (linking our gcm, dsmc, and mhd models), known to accurately reproduce maven observations, for studying the atmospheric ion and photochemical escape rates and climate evolution over the history of mars. | modeling martian atmospheric losses over time: implications for (exo)planetary climate evolution and habitability |
atmospheric escape rate is a key parameter to measure in order to understand the evolution of exoplanets. in this presentation, we will show that the balmer series, observed with high-resolution transmission spectroscopy, is a precise probe to measure exoplanet evaporation, especially for ultra hot jupiters orbiting ea... | measuring and modeling the balmer series in hot gaseous giant exoplanets |
atmospheric escape from exoplanets is a topic of great interest for the exoplanet community since atmospheric retention is an important component of surface habitability. while atmospheric escape has been detected from large exoplanets, it remains difficult to measure for smaller (rocky) planets. indeed, for rocky plan... | atmospheric lifetime from a hypothetical mars-sized planet orbiting barnard's star |
a vast amount--over 700 orbits--of hubble time has been dedicated to characterizing the high energy radiation from m dwarfs over their lifetimes; one key goal is to understand exoplanet environments. the smallest m dwarfs are very different from sun-like stars, with long pre-main sequence lifetimes and a higher fractio... | extending the legacy of hst observations of m dwarfs: coupled models of terrestrial planet thermal evolution and atmosphere loss |
the atmosphere of mars is co2 dominated at lower altitudes, below around 225-250km altitude. through multiple photochemistry paths, the dominant ion species is o2+. dissociative recombination of o2+ ions produces neutral o atoms which have sufficient energy to escape from the planet. the amount of oxygen lost over geol... | the effect of nitrogen chemistry on photochemical escape of oxygen from mars |
one out of four terrestrial planet atmospheres accessible to jwst orbits a flaring m-dwarf. the x-ray light from these flares drives variability in planetary atmospheres, breaking apart molecules, causing atmospheric escape, and complicating interpretation of transit spectra. upcoming jwst observations of a rocky exopl... | a chandra and jwst view of m-dwarf rocky planet atmospheres |
with r~150,000 resolving power and fast tip-tilt image stabilization, the extreme precision spectrometer at the 4.3m lowell discovery telescope is ideally suited for measuring line broadening in planetary gases (jurgenson et al. 2016; petersburg et al. 2020; brewer et al. 2020). here we present measurements sampling be... | measurement of heating in mercury's alkali exotail |
one of the biggest aims in exoplanet science is to understand how planets and their atmospheres evolve. among the several challenges faced while inching towards this goal is the severe lack of observational constraints on the high-energy environments of young exoplanets and their early history of atmospheric escape. in... | resolving the dichotomy of atmospheric escape in the young planet ds tuc a b |
hydrogen escapes to space and iron sinks to the core, leaving oxygen in the middle. does this ever lead to o2 atmospheres? yes, if conditions are right! | a generalized approach to rocky planet oxidation via gravitational differentiation: implications for exoplanets and the solar system |
atmospheric escape from exoplanets is a topic of great interest for the exoplanet community since atmospheric retention is an important component of surface habitability. while atmospheric escape has been detected from large exoplanets, it remains difficult to measure for smaller (rocky) planets. indeed, for rocky plan... | atmospheric lifetime for a hypothetical mars-sized planet orbiting barnard's star |
atmospheric escape from exoplanets is a topic of great interest for the exoplanet community since atmospheric retention is an important component of surface habitability. while atmospheric escape has been detected from large exoplanets, it remains difficult to measure for smaller (rocky) planets. indeed, for rocky plan... | atmospheric escape rates from mars if it orbited an m dwarf star |
hst is the only facility capable of probing the uppermost planetary layers in the ultraviolet, which is key to understanding and modeling the vigorous atmospheric mass-loss seen in highly irradiated exoplanets. recent hst nuv observations of an ultra hot jupiter (uhj) have definitively shown that ionized heavy elements... | heavy metal bands: a study of ions escaping from the hottest jovian atmospheres |
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