The James Webb Space Telescope (JWST) will devote significant observing time to the study of exoplanets. It will not be serviceable as was the Hubble Space Telescope, and therefore the spacecraft/instruments will have a relatively limited life. It is important to get as much science as possible out of this limited observing time. We provide an analysis framework (including publicly released computational tools) that can be used to optimize lists of exoplanet targets for atmospheric characterization. Our tools take catalogs of planet detections, either simulated, or actual; categorize the targets by planet radius and equilibrium temperature; estimate planet masses; generate model spectra and simulated instrument spectra; perform a statistical analysis to determine if the instrument spectra can confirm an atmospheric detection; and finally, rank the targets within each category by observation time required. For a catalog of simulated Transiting Exoplanet Survey Satellite planet detections, we determine an optimal target ranking for the observing time available. Our results are generally consistent with other recent studies of JWST exoplanet target optimization. We show that assumptions about target planet atmospheric metallicity, instrument performance (especially the noise floor), and statistical detection threshold, can have a significant effect on target ranking. Over its full 10-year (fuel-limited) mission, JWST has the potential to increase the number of atmospheres characterized by transmission spectroscopy by an order of magnitude (from about 50 currently to between 400 and 500).
This white paper examines the benefit of the upcoming James Webb Space Telescope for studies of the Solar System's four giant planets: Jupiter, Saturn, Uranus, and Neptune. JWST's superior sensitivity, combined with high spatial and spectral resolution, will enable near- and mid-infrared imaging and spectroscopy of these objects with unprecedented quality. In this paper we discuss some of the myriad scientific investigations possible with JWST regarding the giant planets. This discussion is preceded by the specifics of JWST instrumentation most relevant to giant planet observations. We conclud…
Astrophysics facilities have been of tremendous importance for planetary science. The flagship space observatory Hubble Space Telescope has produced ground-breaking Solar System science, but when launched it did not even have the capability to track moving targets. The next astrophysics flagship mission, the James Webb Space Telescope, included Solar System scientists in its science team from the earliest days, with the result that Webb will launch with a diverse program and capabilities for Solar System exploration. The New Great Observatories, as well as future ground-based facilities, offer…
Principal Component Analysis (PCA)-based techniques can separate data into different uncorrelated components and facilitate the statistical analysis as a pre-processing step. Independent Component Analysis (ICA) can separate statistically independent signal sources through a non-parametric and iterative algorithm. Non-negative matrix factorization is another PCA-similar approach to categorizing dimensions in physically-interpretable groups. Singular spectrum analysis (SSA) is a time-series-related PCA-like algorithm. After an introduction and a literature review on processing JWST data from th…
The coronagraphic instrument currently proposed for the WFIRST-AFTA mission will be the first example of a space-based coronagraph optimized for extremely high contrasts that are required for the direct imaging of exoplanets reflecting the light of their host star. While the design of this instrument is still in progress, this early stage of development is a particularly beneficial time to consider the operation of such an instrument. In this paper, we review current or planned operations on the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST) with a focus on which operat…
The James Webb Space Telescope (JWST) provides the opportunity for ground-breaking observations of asteroids. It covers wavelength regions that are unavailable from the ground, and does so with unprecedented sensitivity. The main-belt and Trojan asteroids are all observable at some point in the JWST lifetime. We present an overview of the capabilities for JWST and how they apply to the asteroids as well as some short science cases that take advantage of these capabilities.
The James Webb Space Telescope (JWST) will revolutionize our understanding of exoplanets with transit spectroscopy of a wide range of mature planets close to their host stars ($<$2 AU) and with coronagraphic imaging and spectroscopy of young objects located further out ($>$10 AU). The census of exoplanets has revealed an enormous variety of planets orbiting stars of all ages and spectral types. With TESS adding to this census with its all-sky survey of the closest, brightest stars, the challenge of the coming decade will be to move from demography to physical characterization. This white paper…
The James Webb Space Telescope (JWST) has the potential to enhance our understanding of near-Earth objects (NEOs). We present results of investigations into the observability of NEOs given the nominal observing requirements of JWST on elongation (85-135 degrees) and non-sidereal rates ($<$30mas/s). We find that approximately 75% of NEOs can be observed in a given year. However, observers will need to wait for appropriate observing windows. We find that JWST can easily execute photometric observations of meter-sized NEOs which will enhance our understanding of the small NEO population.
The James Webb Space Telescope (JWST), currently scheduled to launch in 2021, will dramatically advance our understanding of exoplanetary systems with its ability to directly image and characterise planetary-mass companions at wide separations through coronagraphy. Using state-of-the-art simulations of JWST performance, in combination with the latest evolutionary models, we present the most sophisticated simulated mass sensitivity limits of JWST coronagraphy to date. In particular, we focus our efforts towards observations of members within the nearby young moving groups $β$ Pictoris and TW Hy…
This article summarizes a workshop held on March, 2014, on the potential of the James Webb Space Telescope (JWST) to revolutionize our knowledge of the physical properties of exoplanets through transit observations. JWST's unique combination of high sensitivity and broad wavelength coverage will enable the accurate measurement of transits with high signal-to-noise. Most importantly, JWST spectroscopy will investigate planetary atmospheres to determine atomic and molecular compositions, to probe vertical and horizontal structure, and to follow dynamical evolution, i.e. exoplanet weather. JWST w…
The James Webb Space Telescope (JWST) is optimized for observations in the near and mid infrared and will provide essential observations for targets that cannot be conducted from the ground or other missions during its lifetime. The state of the art science instruments, along with the telescopes moving target tracking, will enable the infrared study, with unprecedented detail, for nearly every object, Mars and beyond, in the solar system. The goals of this special issue are to stimulate discussion and encourage participation in JWST planning among members of the planetary science community. Ke…
The Near-Inrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) is a very versatile instrument, offering multiobject and integral field spectroscopy with varying spectral resolution ($\sim$30 to $\sim$3000) over a wide wavelength range from 0.6 to 5.3 micron, enabling scientists to study many science themes ranging from the first galaxies to bodies in our own Solar System. In addition to its integral field unit and support for multiobject spectroscopy, NIRSpec features several fixed slits and a wide aperture specifically designed to enable high precision time-series and transi…
In this white paper, we assess the potential for JWST to characterize the atmospheres of super-Earth exoplanets, by simulating a range of transiting spectra with different masses and temperatures. Our results are based on a JWST simulator tuned to the expected performance of the workhorse spectroscopic instrument NIRSpec, and is based on the latest exoplanet transit models by Howe & Burrows (2012). This study is especially timely since the observing modes for the science instruments on JWST are finalized (Clampin 2010) and because NASA has selected the TESS mission as an upcoming Explorer. TES…
A number of transiting, potentially habitable Earth-sized exoplanets have recently been detected around several nearby M dwarf stars. These worlds represent important targets for atmospheric characterization for the upcoming NASA James Webb Space Telescope. Given that available time for exoplanet characterization will be limited, it is critically important to first understand the capabilities and limitations of JWST when attempting to detect atmospheric constituents for potentially Earth-like worlds orbiting cool stars. Here, we explore coupled climate-chemistry atmospheric models for Earth-li…
The James Webb Space Telescope will enable a wealth of new scientific investigations in the near- and mid-infrared, with sensitivity and spatial/spectral resolution greatly surpassing its predecessors. In this paper, we focus upon Solar System science facilitated by JWST, discussing the most current information available concerning JWST instrument properties and observing techniques relevant to planetary science. We also present numerous example observing scenarios for a wide variety of Solar System targets to illustrate the potential of JWST science to the Solar System community. This paper u…
The largest trans-Neptunian objects (TNOs) represent an extremely diverse collection of primitive bodies in the outer solar system. The community typically refers to these objects as dwarf planets, though the IAU acknowledges only four TNOs officially as such: Pluto, Eris, Makemake, and Haumea. We present a list of 36 potential candidates for reclassification as dwarf planets, namely candidate dwarf planets (CDPs), which cover a wide range of sizes, geometric albedos, surface colors and probably, composition. Understanding the properties across this population, and how those properties change …
The James Webb Space Telescope (JWST) may be capable of finding biogenic gases in the atmospheres of habitable exoplanets around low mass stars. Considerable attention has been given to the detectability of biogenic oxygen, which could be found using an ozone proxy, but ozone detection with JWST will be extremely challenging, even for the most favorable targets. Here, we investigate the detectability of biosignatures in anoxic atmospheres analogous to those that likely existed on the early Earth. Arguably, such anoxic biosignatures could be more prevalent than oxygen biosignatures if life exis…
Transiting exoplanets orbiting active stars frequently occult starspots and faculae on the visible stellar disc. Such occultations are often rejected from spectrophotometric transits, as it is assumed they do not contain relevant information for the study of exoplanet atmopsheres. However, they can provide useful constraints to retrieve the temperature of active features and their effect on transmission spectra. We analyse the capabilities of the James Webb Space Telescope in the determination of the spectra of occulted starspots, despite its lack of optical wavelength instruments on board. Fo…
The near-term search for life beyond the solar system currently focuses on transiting planets orbiting small M dwarfs, and the challenges of detecting signs of life in their atmospheres. However, planets orbiting white dwarfs (WDs) would provide a unique opportunity to characterize rocky worlds. The discovery of the first transiting giant planet orbiting a white dwarf, WD 1856+534b, showed that planetary-mass objects can survive close-in orbits around WDs. The large radius ratio between WD planets and their host renders them exceptional targets for transmission spectroscopy. Here, we explore t…
The James Webb Space Telescope (JWST), as the largest space-based astronomical observatory with near- and mid-infrared instrumentation, will elucidate many mysterious aspects of comets. We summarize four cometary science themes especially suited for this telescope and its instrumentation: the drivers of cometary activity, comet nucleus heterogeneity, water ice in comae and on surfaces, and activity in faint comets and main-belt asteroids. With JWST, we can expect the most distant detections of gas, especially CO2, in what we now consider to be only moderately bright comets. For nearby comets, …
For the past 400 years, astronomers have sought to observe and interpret the Universe by building more powerful telescopes. These incredible instruments extend the capabilities of one of our most important senses, sight, towards new limits such as increased sensitivity and resolution, new dimensions such as exploration of wavelengths across the full electromagnetic spectrum, new information content such as analysis through spectroscopy, and new cadences such as rapid time-series views of the variable sky. The results from these investments, from small to large telescopes on the ground and in s…
It is widely anticipated that the James Webb Space Telescope (JWST) will be transformative for exoplanet studies. It has even been suggested that JWST could provide the first opportunity to search for biosignatures in an alien atmosphere using transmission spectroscopy. This claim is investigated, specifically for the proposed anoxic biosignature pair CH4-CO2. The most favourable known target is adopted (TRAPPIST-1e), with an assumed atmospheric composition similar to the Archean Earth. Compared to previous studies, a more systematic investigation of the effect that cloud/haze-layers have on t…
Exoplanets with radii between those of Earth and Neptune have stronger surface gravity than Earth, and can retain a sizable hydrogen-dominated atmosphere. In contrast to gas giant planets, we call these planets gas dwarf planets. The James Webb Space Telescope (JWST) will offer unprecedented insight into these planets. Here, we investigate the detectability of ammonia (NH$_{3}$, a potential biosignature) in the atmospheres of seven temperate gas dwarf planets using various JWST instruments. We use petitRadTRANS and PandExo to model planet atmospheres and simulate JWST observations under differ…
The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $μ$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam and MIRI, noting that science with NIRISS will be complementary. Five core scientific themes are identified: (i) surface (ii) tropospheric clouds (iii) tropospheric gases (iv) stratospheric composition …
Terrestrial planets orbiting M dwarfs may soon be observed with the James Webb Space Telescope (JWST) to characterize their atmospheric composition and search for signs of habitability or life. These planets may undergo significant atmospheric and ocean loss due to the superluminous pre-main-sequence phase of their host stars, which may leave behind abiotically-generated oxygen, a false positive for the detection of life. Determining if ocean loss has occurred will help assess potential habitability and whether or not any O2 detected is biogenic. In the solar system, differences in isotopic ab…
Doppler and transit surveys are finding extrasolar planets of ever smaller mass and radius, and are now sampling the domain of superEarths (1-3 Earth radii). Recent results from the Doppler surveys suggest that discovery of a transiting superEarth in the habitable zone of a lower main sequence star may be possible. We evaluate the prospects for an all-sky transit survey targeted to the brightest stars, that would find the most favorable cases for photometric and spectroscopic characterization using the James Webb Space Telescope (JWST). We use the proposed Transiting Exoplanet Survey Satellite…
Alpha Centauri A is the closest solar-type star to the Sun and offers an excellent opportunity to detect the thermal emission of a mature planet heated by its host star. The MIRI coronagraph on JWST can search the 1-3 AU (1"-2") region around alpha Cen A which is predicted to be stable within the alpha Cen AB system. We demonstrate that with reasonable performance of the telescope and instrument, a 20 hr program combining on-target and reference star observations at 15.5 um could detect thermal emission from planets as small as ~5 RE. Multiple visits every 3-6 months would increase the geometr…
Hydrocarbon Hazes on Temperate sub-Neptune K2-18b supported by data from the James Webb Space Telescope
University College London（伦敦大学学院）；Universite de Reims Champagne Ardenne（兰斯香槟阿登大学）；King’s College London（伦敦国王学院）；Osservatorio Astronomico di Palermo（巴勒莫天文台）
Disintegrating planets allow for the unique opportunity to study the composition of the interiors of small, hot, rocky exoplanets because the interior is evaporating and that material is condensing into dust, which is being blown away and then transiting the star. Their transit signal is dominated by dusty effluents forming a comet-like tail trailing the host planet (or leading it, in the case of K2-22b), making these good candidates for transmission spectroscopy. To assess the ability of such observations to diagnose the dust composition, we simulate the transmission spectra from 5-14 $μ$m fo…
A Comprehensive Atmospheric Retrieval Analysis of 22 James Webb Space Telescope Spectral Energy Distributions of Cool Brown Dwarfs
University of Toledo（托莱多大学）；Dordt University（道特大学）；University of Arizona（亚利桑那大学）；University of Hertfordshire（赫特福德大学）；United States Naval Observatory（美国海军天文台）；Caltech（加州理工学院）
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…
Planets emit thermal radiation and reflect incident light that they recieve from their host stars. As a planet orbits it's host star the photometric variations associated with these two effects produce very similar phase curves. If observed through only a single bandpass this leads to a degeneracy between certain planetary parameters that hinder the precise characterization of such planets. However, observing the same planet through two different bandpasses gives one much more information about the planet. Here, we develop a Bayesian methodology for combining photometry from both \emph{Kepler}…
We use thermodynamic calculations to model atmospheric chemistry on terrestrial exoplanets that are hot enough for chemical equilibira between the atmosphere and lithosphere, as on Venus. The results of our calculations place constraints on abundances of spectroscopically observable gases, the surface temperature and pressure, and the mineralogy of the surface. These results will be useful in planning future observations of the atmospheres of terrestrial-sized exoplanets by current and proposed space observatories such as the Hubble Space Telescope (HST), Spitzer, James Webb Space Telescope (J…
The James Webb Space Telescope (JWST) will perform exoplanet transit spectroscopy in the coming decade promising transformative science results. All four instruments on board can be used for this technique which reconstructs the atmospheric transmission or emission spectrum of an exoplanet from wavelength-dependent light curve measurements. Astrophysical and instrumental noise and systematics can affect the precision and accuracy of the final spectrum, and hence, the atmospheric properties derived from the spectrum. Correlated noise and time-dependent systematics that can bias the measured sig…
Characterization of the atmospheres of transiting exoplanets relies on accurate measurements of the extent of the optically thick area of the planet at multiple wavelengths with a precision $\lesssim$100 parts per million (ppm). Next-generation instruments onboard the James Webb Space Telescope (JWST) are expected to achieve $\sim$10 ppm precision for several tens of targets. A similar precision can be obtained in modelling only if other astrophysical effects, including the stellar limb-darkening, are accounted for properly. In this paper, we explore the limits on precision due to the mathemat…
Characterization of exoplanets has matured in recent years, particularly through studies of exoplanetary atmospheres of transiting planets at infra-red wavelenegths. The primary source for such observations has been the Spitzer Space Telescope but these studies are anticipated to continue with the James Webb Space Telescope (JWST). A relatively unexplored region of exoplanet parameter space is the thermal detection of long-period eccentric planets during periastron passage. Here we describe the thermal properties and albedos of long-period giant planets along with the eccentricities of those o…
Much of the focus of exoplanet atmosphere analysis in the coming decade will be at infrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the Wide-Field Infrared Survey Telescope (WFIRST). However, without being placed in the context of broader wavelength coverage, especially in the optical and ultraviolet, infrared observations produce an incomplete picture of exoplanet atmospheres. Scattering information encoded in blue optical and near-UV (NUV) observations can help determine whether muted spectral features observed in the infrared are due to a hazy/clo…
We investigate the relativistic effects in the orbital motion of the exoplanet HD80606b with a high eccentricity of $e\simeq0.93$ .We propose a method to detect these effects (notably the orbital precession) based on measuring the successive eclipse and transit times of the exoplanet. In the case of HD80606b, we find that in ten years (after approximately 33 periods) the instants of transits and eclipses are delayed with respect to the Newtonian prediction by about three minutes due to relativistic effects. These effects can be detected by comparing at different epochs the time difference betw…
Detection of water vapor in the atmosphere of temperate rocky exoplanets would be a major milestone on the path towards characterization of exoplanet habitability. Past modeling work has shown that cloud formation may prevent the detection of water vapor on Earth-like planets with surface oceans using the James Webb Space Telescope (JWST). Here we analyze the potential for atmospheric detection of H2O on a different class of targets: arid planets. Using transit spectrum simulations, we show that atmospheric H2O may be easier to be detected on arid planets with cold-trapped ice deposits on the …
Following the discovery of the first exoplanet candidate transiting a white dwarf (WD), a "white dwarf opportunity" for characterizing the atmospheres of terrestrial exoplanets around WDs is emerging. Large planet-to-star size ratios and hence large transit depths make transiting WD exoplanets favorable targets for transmission spectroscopy - conclusive detection of spectral features on an Earth-like planet transiting a close-by WD can be achieved within a medium James Webb Space Telescope (JWST) program. Despite the apparently promising opportunity, however, the post-main sequence (MS) evolut…
Much of the focus of exoplanet atmosphere analysis in the coming decade will be atinfrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the Wide-Field Infrared Survey Telescope (WFIRST). However, without being placed in the context of broader wavelength coverage, especially in the optical and ultraviolet, infrared observations produce an incomplete picture of exoplanet atmospheres. Scattering information encoded in blue optical and near-UV observations can help determine whether muted spectral features observed in the infrared are due to a hazy/cloudy atm…
Exoplanets with cloud-free, haze-free atmospheres at the pressures probed by transmission spectroscopy represent a valuable opportunity for detailed atmospheric characterization and precise chemical abundance constraints. We present the first optical to infrared (0.3-5 microns) transmission spectrum of the hot Jupiter WASP-62b, measured with Hubble/STIS and Spitzer/IRAC. The spectrum is characterized by a 5.1-sigma detection of Na I absorption at 0.59 microns, in which the pressure-broadened wings of the Na D-lines are observed from space for the first time. A spectral feature at 0.4 microns i…
The current sparse wavelength range coverage of exoplanet direct imaging observations, and the fact that models are defined using a finite wavelength range, lead both to uncertainties on effective temperature determination.We study these effects using black-bodies and atmospheric models and we detail how to infer this parameter. Through highlighting the key wavelength coverage that allows for a more accurate representation of the effective temperature, our analysis can be used to mitigate or manage extra uncertainties being added in the analysis from the models. We find that the wavelength ran…
Methane has been proposed as an exoplanet biosignature. Imminent observations with the James Webb Space Telescope may enable methane detections on potentially habitable exoplanets, so it is essential to assess in what planetary contexts methane is a compelling biosignature. Methane's short photochemical lifetime in terrestrial planet atmospheres implies that abundant methane requires large replenishment fluxes. While methane can be produced by a variety of abiotic mechanisms such as outgassing, serpentinizing reactions, and impacts, we argue that, in contrast to an Earth-like biosphere, known …
We present here the first application of Stellar and Exoplanetary Atmospheres Bayesian Analysis Simultaneous Spectroscopy (SEA BASS) on real datasets. SEA BASS is a scheme that enables the simultaneous derivation of four-coefficient stellar limb-darkening profiles, transit depths, and orbital parameters from exoplanetary transits at multiple wavelengths. It relies on the wavelength-independence of the system geometry and on the reduced limb-darkening effect in the infrared. This approach has been introduced by Morello et al. (2017) (without the SEA BASS acronym), who discuss several tests on s…
