What Is The Physical Makeup Of Jupiters Atmosphere

Jupiter Atmosphere

Atmospheres of the Giant Planets

West Robert A. , in Encyclopedia of the Solar System (Second Edition), 2007

1. Introduction

To be an astronaut explorer in Jupiter's atmosphere would be strange and disorienting. At that place is no solid ground to stand on. The temperature would be comfy at an altitude where the pressure level is 8 times that of Earth'south surface, simply information technology would be perpetually hazy overhead, with variable conditions (dry out or wet, cloudy or non) to the e, due west, north, and south. Ane would need to carry oxygen as there is no free oxygen, and to wear special vesture to protect the skin against exposure to ammonia, hydrogen sulfide, and ammonium hydrosulfide gases, which class clouds and haze layers higher in the atmosphere. A trip to high latitudes would offering an opportunity to watch the well-nigh powerful, vibrant, and continuous auroral displays in the solar organization. On the way, one might pass through individual storm systems the size of Earth or larger and be buffeted past strong winds alternately from the due east and west. Ane might exist sucked into a dry downwelling sinkhole like the environment explored by the Galileo probe. The probe fell to depths where the temperature is hot enough to vaporize metal and rock. It is now a function of Jupiter's atmosphere.

Although the atmospheres of the giant planets share many common attributes, they are at the same time very diverse. The roots of this diverseness can exist traced to a set up of basic properties, and ultimately to the origins of the planets. The most important properties that influence atmospheric behavior are listed in Table 1. The distance from the Sun determines how much sunlight is bachelor to heat the upper atmosphere. The minimum temperature for all of these atmospheres occurs almost the 100 mbar level and ranges from 110 Yard at Jupiter to 50 One thousand at Neptune. The distance from the Sun and the total mass of the planet are the primary influences on the bulk composition. All the giant planets are enriched in heavy elements, relative to their solar abundances, by factors ranging from about 3 for Jupiter to g for Uranus and Neptune. The latter two planets are sometimes chosen the water ice giants because they have a big fraction of elements (O, C, N, and S) that were the primary constituents of ices in the early on solar nebula.

Tabular array 1. Physical Properties of the Giant Planets

Property	Jupiter	Saturn	Uranus	Neptune
Distance from the Sun (Earth distance = 1 ^a )	5.2	9.half dozen	19.2	30.1
Equatorial radius (Earth radius = 1 ^b )	11.3	9.iv	4.1	3.ix
Planet total mass (Earth mass = i ^c )	318.ane	95.one	xiv.6	17.2
Mass of gas component (Earth mass = one)	254–292	72–79	i.3–iii.6	0.7–3.2
Orbital period (years)	11.9	29.6	84.0	164.eight
Length of day (hours, for a point rotating with	9.nine	ten.7	17.iv	xvi.2
the interior
Axial inclination (degrees from	3.1	26.7	97.ix	28.8
normal to orbit plane)
Surface gravity (equator–pole, one thousand south ^{− 2})	(22.5–26.3)	(8.iv–eleven.half dozen)	(8.2–viii.eight)	(x.viii–11.0)
Ratio of emitted thermal energy to captivated	one.7	ane.viii	∼one	2.6
solar free energy
Temperature at the 100-mbar level (K)	110	82	54	50

a: Globe distance = 1.5 × 10^eight km.
b: Globe radius = 6378 km.
c: Earth mass = half-dozen × x²⁴ kg.

The orbital menstruum, centric tilt, and distance from the Dominicus determine the magnitude of seasonal temperature variations in the loftier atmosphere. Jupiter has weak seasonal variations; those of Saturn are much stronger. Uranus is tipped such that its poles are nearly in the orbital aeroplane, leading to more solar heating at the poles than at the equator when averaged over an orbit. The ratio of radiated thermal energy to absorbed solar energy is diagnostic of how rapidly convection is bringing internal rut to the surface, which in plough influences the abundance of trace constituents and the morphology of eddies in the upper atmosphere. Vigorous convection from the deeper interior is responsible for unexpectedly high abundances of several trace species on Jupiter, Saturn, and Neptune, just convection on Uranus is sluggish. All these subjects are treated in more than detail in the sections that follow.

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Interiors of the Giant Planets

Mark S. Marley , Jonathan J. Fortney , in Encyclopedia of the Solar System (Second Edition), 2007

5.2 Jupiter

Jupiter contains more than mass than that of all the other planets combined. Considering Jupiter'south gravitational harmonics are also best known, it serves as a examination bed for theoretical understanding of jovian interiors. The observed physical characteristics of Jupiter are listed in Table 1. From Galileo Entry Probe data, abundance of methane in Jupiter'due south atmosphere is well-nigh 3.5 times the solar abundance and the abundance of ammonia is about three times solar. Water does non show such enrichment, but it has been argued that the Galileo Entry Probe fell into an anomalously dry out region of Jupiter's atmosphere.

The full general structure of Jupiter'southward interior was briefly described in Section i. Modern interior models effort to make up one's mind specifically the degree of enrichment of heavy elements in the hydrogen/helium envelope of the planet. The atmospheric enrichment of marsh gas and ammonia provides some indication that heavy element enrichment in the deeper interior may be expected. Jupiter's λ ₂ implies that Jupiter is not homogeneous merely is slightly centrally condensed. Indeed, detailed modeling has shown that Jupiter's current core is less than 10 Earth masses and that in that location may not be a core at all. The size and composition of jovian planet cores and the corporeality of heavy element enrichment in the envelopes have begetting on the scenarios by which they are supposed to accept formed.

The variations of density with a radius for two typical Jupiter models are shown in Fig. 7. It should exist emphasized that these are two Jupiter models that are consistent with all available constraints. Other, equally valid interior models be. Figure eight shows the mass of heavy elements in the cores and hydrogen–helium envelopes for a large number of Jupiter and Saturn models. Any model within the solid red line is a valid interior model for Jupiter, given the current uncertainties in the EOS of hydrogen. Models within the hashed line expanse are tentatively preferred, given the most recent experimental EOS information. The majority of Jupiter'due south heavy elements are found within the hydrogen–helium envelope, not within the core. The models as well account for uncertainty related to the unknown composition of the core, which is likely some mixture of ice and rock.

A clear trend of Jupiter modeling over the past 30 years is that as we have gained meliorate cognition of the EOS of hydrogen, the calculated mass of the core has shrunk.

Surrounding the core is an envelope of hydrogen and helium. The temperature and force per unit area at the lesser of the hydrogen–helium envelope is well-nigh 20,000 K and 40 Mbar for typical models. The gravitational harmonics require the envelope to be denser at each force per unit area level than a model that has only a solar mixture of elements. Thus, the envelope must be enriched in heavy elements compared to a purely solar composition. The total mass of heavy elements is constrained between 10 and 40 Earth masses. If Jupiter had only a solar abundance of heavy elements, this value would be 6 World masses. This ways that, averaged throughout the planet, Jupiter is enriched in heavy elements over solar abundances by a factor of 1.5 to vi.

Jupiter's atmospheric affluence of helium, Y = 0.238 ± 0.007, is less than the solar abundance of about 0.28. This depletion is likely an indication that the process of helium differentiation, described more fully in Section 6, may accept recently begun on Jupiter. The interior models practise non provide a sufficiently clear view into the interior construction to determine if this is the case. The inferred interior structure is, however, compatible with limited helium differentiation.

Hydrogen and helium etch well-nigh 90% of Jupiter's mass. Virtually of the hydrogen exists in the form of metallic hydrogen. Jupiter is the largest reservoir of this fabric in the solar system. Convection in the metallic hydrogen interior is likely responsible for the generation of Jupiter's magnetic field. The transition from molecular to metallic hydrogen takes place virtually 10,000 km beneath the cloud tops, compared to about 30,000 km at Saturn. The exceptionally big volume of metallic hydrogen is probable responsible for the great strength of Jupiter's magnetic field. The relative proximity of the electrically conductive region to the surface may explain why Jupiter's magnetic field is more than complex than Saturn's.

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Planetary Geology

Raymond East. Arvidson , in Encyclopedia of Physical Science and Engineering (3rd Edition), 2003

II.C Analyses

Equally noted, Fig. 5 shows the electric current volume of digital planetary image data and volumes expected from missions to be flown in the 1990s. For example, the Magellan mission to Venus will double the existing amount of digital planetary image data within almost 243 days of mapping operations. The overall volume is expected to increase exponentially with a doubling interval of simply several years when averaged over the 1990s. Data complexity is expected to increase at a comparable rate. For example, the Galileo orbiter, expected to begin mapping operations in the Jovian orbit in 1995, will bear a near-infrared mapping spectrometer (NIMS) capable of generating detached images at numerous narrow wavelength intervals. The NIMS will be complemented past a multispectral imaging arrangement using accuse-coupled device detectors. Data expected from the 2 instruments will enable new studies of Jupiter'due south temper, its band, and the large group of satellites associated with the planet.

The increase in volume and complexity of data sets expected in the 1990s is a upshot of two activities, proceeding in parallel. Kickoff, science and measurement objectives are becoming more complex every bit knowledge of planetary bodies and systems increases and more complex questions are posed. Second, technology is keeping pace, offer new observational capabilities and programmable instruments with numerous operating modes.

The expected increase in data volume and complexity requires efficient mechanisms for planning sequences of observations for information access, analysis, and archiving. The increased computation and data direction capabilities expected in the 1990s volition allow mission operations and data analyses to be geographically distributed, with researchers working at their dwelling house institutions and interacting with mission personnel over networks. New analysis techniques are also being developed to cope with growing data volumes and complication. The NASA Planetary Data System was developed in response to the challenges associated with managing, distributing, processing, and archiving the expected information sets. This organization, managed by the Jet Propulsion Laboratory, is based on a geographically distributed network of sites or nodes that have experts involved for various information sets. Data about data, bodily data, and selected processing procedures will be available to NASA's research community through the planetary data system. For case, compact disk read-just memory (CD-ROMs) platters are being utilized as a standard distribution medium for digital information, since each disk holds 550 million bytes of data. With CD-ROMs, hundreds of copies can be generated, significantly lowering reproduction costs over, for example, copying magnetic tapes. Even college volumes are obtained for data sets that can exist compressed. For example, Voyager image data are being distributed on CD-ROMs in a lossless, compressed form, where each disk holds the equivalent of 2 billion bytes of image data.

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Radio Astronomy, Planetary

Samuel Gulkis , Imke de Pater , in Encyclopedia of Physical Science and Technology (Third Edition), 2003

IV.D Jupiter

Jupiter was the first planet detected at radio wavelengths. The discovery observations occurred in 1955, at the very low frequency of 22.ii MHz. Prediscovery observations of Jupiter were later traced dorsum to 1950. Subsequent observations of Jupiter revealed that its radio spectrum is exceedingly complex, showing both thermal and nonthermal emission mechanisms. Thermal emission from the atmosphere dominates the Jovian spectrum shortward of 7 cm. Nonthermal synchrotron emission dominates the spectrum from ∼three m to 7 cm; brightness temperatures exceed ten^v K for the synchrotron component. Longward of vii.5 m, Jupiter emits potent and sporadic nonthermal radiation. The radiation exhibits complex frequency, time, and polarization structure. The brightness temperature of this component exceeds 10¹⁷ K, suggesting a coherent source of emission. The schematic appearance of Jupiter's spectrum is shown in Fig. xi.

Observations of Jupiter at high athwart resolution with radio interferometers take been used to map the synchrotron radiation from Jupiter's radiations belts and to separate the thermal from the nonthermal synchrotron components. The nonthermal component is easily identifiable with a radio interferometer because it is greatly extended relative to the optical disk of Jupiter and is strongly linearly polarized.

The thermal component originates in the Jovian atmosphere. The observations are consequent with a deep model atmosphere, equanimous generally of hydrogen and helium, in convective equilibrium. The principal source of opacity is ammonia (NH₃), which exhibits very strong absorption in the microwave spectral region.

In December 1995 the Galileo spacecraft released a probe into the atmosphere of Jupiter, which relayed its findings to the spacecraft via radio signals at a frequency of i.4 GHz. By analyzing the attenuation of the probe radio signal, the ammonia abundance in Jupiter's deep atmosphere (at pressures over 8 bar) was derived to be a factor of ∼iii.v larger than the solar N value. Ground-based microwave measurements are virtually sensitive to layers where the clouds form (∼0.five bar) down to roughly 10–15 bar. The ground-based microwave measurements exercise non show as much ammonia as the probe. Apparently, the ammonia abundance in Jupiter's deep temper is significantly decreased at higher altitudes, to roughly one-half the solar N value just below the upper cloud deck. Scientists do non still understand why in that location is and then much less ammonia in the upper regions of Jupiter's temper compared to deeper layers.

VLA images resolve the disk of Jupiter and show the familiar zone-belt structure at two–vi cm. Figure 12 shows a 1.ii-arc sec resolution VLA radio image at ii-cm wavelength. The disk bore of Jupiter was 32 arc sec at the time of the radio observations. Radio images, such equally shown in Fig. 12, are ordinarily smeared in longitude, since the observations are integrated over a substantial time interval. The bright (white) beltlike regions are indicative of a higher brightness temperature, which is likely due to a relative depletion of NH₃ gas compared to the darker colored regions. Since the radio waves originate in and below the visible cloud layers, such images contain information complementary to that obtained at IR and optical wavelengths. From the images, the latitudinal variation of NH₃ gas can be obtained, in addition to the altitude distribution. Such variations must exist due to dynamical processes on the planets, for example, zonal winds, upwelling, and subsidence of gas. The zone-belt structure on Jupiter is consistent with upwelling gas in the zones and subsidence in the belts. Images taken in different years show clear variations in the zone-chugalug structure, indicative of meteorological changes.

Radio interferometric maps of Jupiter'south synchrotron emission have been made at a number of different wavelengths. It has been possible to deduce a slap-up deal of information near Jupiter's magnetosphere from the radio measurements. The radio astronomical measurements provided convincing proof that Jupiter has a strong magnetic field, and this information was used to design the offset spacecraft sent to Jupiter. The radio measurements show that the magnetic field is primarily dipolar in shape with the dipole centrality tilted nigh 10° with respect to Jupiter's rotational axis. Using the well-developed theory of synchrotron emission (summarized in Section Ii.C), it has been possible to determine energies and densities of the high-free energy electrons that are trapped in Jupiter's magnetic field.

Figure 13 shows a radio image of Jupiter'southward synchrotron radiation. The main radiation peaks are indicated past the messages L and R, and the high-breadth emission peaks by Ln, Ls, Rn, and Rs. Magnetic field lines at jovicentric distances of one.5 and 2.5 (from the O6 magnetic field model) are superimposed. The resolution is 0.3 Jovian radii, roughly the size of the high-latitude emission regions. Thermal emission from Jupiter's temper appears as a deejay-shaped region in the center of the effigy.

Effigy xiv shows a tomographic map of the emission region, obtained by observing Jupiter at all longitudes and reconstructing a three-dimensional map. The emission is seen to be confined to the magnetic equatorial aeroplane out to a distance of ∼4 Jovian radii. Several intriguing features are visible. The master radiation peaks (Fifty and R on Fig. 13) are usually asymmetric. One of the peaks appears to be brighter than the other tiptop. The asymmetry of these principal radiation peaks is caused by deviations in Jupiter's magnetic field from a pure dipole configuration. These deviations are evident in Fig. 14, where the principal band of radiation is clearly warped like the surface of a spud bit. If Jupiter'south field were a dipole field, this ring would exist apartment, and the radiation peaks (Fig. 13) would always be equal in intensity, though the intensity would vary with jovian rotation, such that information technology would be smallest when one of the magnetic poles is directed toward united states. The secondary emission peaks (Ln, Ls, Rs, Rn in Fig. 13) become high-latitude rings when viewed in a three-dimensional paradigm. These peaks are produced by electrons at their mirror points, and they reveal the presence of a relatively large number of electrons which bounce up and downwardly the field lines at a Jovian altitude of ii–2.five Jovian radii. It is believed that these electrons may have been scattered out of the magnetic equatorial airplane, maybe by the Moon Amalthea, which orbits Jupiter at a altitude of two.five Jovian radii.

The full radio intensity of Jupiter varies significantly over time (years), and appears to be correlated with solar current of air parameters. The impact of comet D/Shoemaker-Levy 9 with Jupiter in July 1994 caused a sudden sharp increase in Jupiter's total flux density, by ∼twenty%. At the same time the effulgence distribution of the radio flux density changed drastically. These observations suggest that the impact and associated phenomena significantly modified the electron distribution and perhaps the magnetic field also.

At frequencies below xl MHz, Jupiter is a strong emitter of desultory nonthermal radiations. A decameter-wavelength (DAM) component observable from the ground is characterized by circuitous, highly organized structure in the frequency–time domain and dependent on the observer's position relative to Jupiter. The satellite Io modulates the DAM emission. The Voyager spacecraft added significantly to our knowledge of this low-frequency component when it flew by Jupiter in 1979. A kilometric-wavelength (KOM) component was discovered at frequencies below 1 MHz and the observations of the DAM component were significantly improved. The extremely high effulgence temperatures (>x¹⁷ K), narrow-bandwidth emissions, and desultory nature all suggest that the very low frequency emissions from Jupiter are generated by energetic particles interim coherently and interacting with the plasma that surrounds Jupiter. The details of the emission process are non well understood.

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PLANETARY ATMOSPHERES | Jupiter and the Outer Planets

A.P. Showman , in Encyclopedia of Atmospheric Sciences, 2003

Vertical Structure and Clouds

The temperature profiles at pressures less than a few confined (1 bar10^five Pa) accept been measured for all iv behemothic planets by radio occultations from the Voyager spacecraft and, in the example of Jupiter, by the Galileo probe to 22 bars (Figure 2). Each planet exhibits a temperature minimum (tropopause) most 100 mbar, with a troposphere below and a stratosphere above. The temperature slope (lapse rate) in the troposphere approaches the dry out adiabatic value at pressures exceeding about 1 bar. Galileo probe measurements signal that Jupiter's atmosphere is close to a dry adiabat from 1 to 22 bars. All 4 planets also accept hot thermospheres, with temperatures ranging from ∼600 to 1000 G at pressures of 10⁻³ μbar or less. The thermospheric temperatures are greater than can exist achieved with solar energy absorption and, interestingly, do not bear witness a systematic decrease with altitude from the Sun. At such altitudes, thermal energy is quickly conducted downward, so a large heat source is required. Possibilities include deposition of energy from charged particles impinging on the top of the temper (almost relevant to Jupiter) and dissipation of gravity or acoustic waves that propagate up from lower altitudes.

At pressures greater than about 1 bar, the giant planets' vertical heat flux is carried by convection. Infrared radiation escapes directly to infinite at pressures of 100 to 300 mbar.

Condensation of trace species leads to the germination of clouds at most 1–ten confined (Table 3). On Jupiter and Saturn, the expected condensates are, from high to low pressure, water (H_twoO), ammonium hydrosulfide (NH₄SH, which condenses from gaseous NH₃ and H₂S), and ammonia (NH₃). On Uranus and Neptune, the condensates are H₂O, NH₄SH, either NH₃ or H_twoS (depending on the nitrogen to sulfur ratio), and methane (CH₄).

Table 3. Condensation pressures on behemothic planets (confined)

Species	Jupiter	Saturn	Uranus	Neptune
CH_four	–	–	ane.2	ane.five
NH₃	0.half dozen	1.4	3 ^a	iii ^a
H₂S	–	–	∼5 ^a	∼5 ^a
NH_ivSH	2	4	∼30 ^b	∼30 ^b
H₂O	6	∼15 ^b	∼300 ^b	∼300 ^b

a: Either NH₃ or H_iiSouth deject expected (depending on relative abundance of NH₃ and H₂S) simply not both.
b: Uncertain; depends on (poorly known) composition.

Analyses of infrared spectra let the bodily cloud structure to be inferred. For Jupiter and Saturn, the top cloud is a global layer at pressures almost 0.5–1 bar. These clouds are thought to consist of NH₃ ice from a comparing with Table 3. (Solid ammonia absorption features take been observed only in localized active clouds, however. Possibly the ammonia ice across almost of the planet is chemically modified or coated with impurities that mask the absorption features.) Cloud particles range from ane to 100 μm in size. Some studies of infrared spectra suggest that on Jupiter a cloud exists at two bars, where NH_fourSH is expected to condense. No global cloud is present at v bars, but sporadic local clouds have been seen with tops at pressures exceeding 4 confined, where the but possible condensate is water. On both Jupiter and Saturn, the 0.v–1 bar cloud is overlaid past an optically thin, homogeneous haze from 0.one–0.5 bar.

On Uranus and Neptune, two tropospheric deject layers have been observed. The lowermost deject forms an opaque global layer with tops at 2.viii±0.5 and 3.eight±0.half dozen confined on Uranus and Neptune, respectively. The composition may be H₂Due south on the basis of a comparison with Table 3 and observations showing that gaseous NH₃ is extremely depleted. At pressures of ane.two and 1.five bars on Uranus and Neptune, respectively, a patchy, marsh gas-water ice cloud with optical depths of 0.1–1 exists.

Sparse haze layers are also nowadays in the stratospheres of all four behemothic planets; these result from condensation of methane photolysis products such as ethane (C₂H_half-dozen), acetylene (C_twoH₂), and higher-gild organics. Vaporization (and subsequent condensation) of fabric from incoming interplanetary dust particles also provides a small-scale source of upper-atmospheric aerosols.

The colors of the behemothic planets remain poorly understood. Ammonia ice is colorless; the globe tones exhibited past Jupiter and Saturn result from trace quantities of solid organic, sulfur, or phosphorus compounds ('chromophores') mixed in with the ammonia ice. The blue-green colors of Uranus and Neptune result from absorption of reddish calorie-free past gaseous methane and perhaps by particles in the global cloud most three bars.

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JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system

O. Grasset , ... T. Van Hoolst , in Planetary and Space Science, 2013

v.1 The Jupiter tour

Beginning on approach to Jupiter, long term monitoring of Jupiter's atmosphere and magnetospheric processes and dynamics volition exist initiated and volition be performed throughout the initial orbit phases at Jupiter using the remote sensing and in situ measurement capability of JUICE's instrumentation. The tour at Jupiter will include two targeted Europa flybys observing the composition of Europa'southward not-water-ice material, and performing the outset subsurface observations of an icy moon. The Europa flybys volition be performed from a 4:1 resonant orbit, where Europa will be encountered at perijove. The flyby orbits volition be initiated and terminated with Callisto gravity assists, which is most efficient for propellant consumption and for radiation exposure. The planned observing sequence is optimised for both remote sensing and in situ measurements and is illustrated in Fig. 14, where JUICE's distance is plotted as a function of time, and the operations of the instruments are indicated past dissimilar colours. The in situ instruments (plasma spectrometers, magnetometer) will be operated during the entire flyby (ruby line in Fig. 14a); the photographic camera will be imaging the surface during the entire flyby, while the sub-nadir bespeak is in sunlight, starting from virtually ten,000 km altitude (yellow line in Fig. fourteena); the imaging spectrometers volition be operated from 10,000 to chiliad km altitudes (orange line in Fig. 14a); during closest arroyo (<k km altitude, closest approach is ∼400 km) the ice-penetrating radar and the laser altimeter volition be the prime instruments (green line in Fig. 14a). With this remainder of musical instrument operations the achievement of main science goals can be satisfied.

JUICE investigations on Europa will be focused on the limerick of the non-water-ice textile, organic chemical science, and the commencement subsurface observations of an icy moon, including the first determination of the minimal thickness of the icy crust over the most active regions. Specifically, for the chosen Europa flyby observation sequences, the sampling of the tenuous atmosphere, the coverage of surface geological features, the induced magnetic field and the properties and structure of the tiptop ice layer can exist characterised. Equally is also indicated in Fig. 14b, the footing tracks at closest approaches for the two flybys are separated in latitude, demonstrating that the detailed remote sensing can exist achieved at different areas of specific involvement, suspected to be active regions or possibly having the thinnest water ice layer. From all the possible sites with loftier potential for geology, chemical science and astrobiology (meet red areas in Fig. 14b), Thera and Thrace Macula and Lenticulae are currently selected for closest arroyo during the 2 flybys.

In the post-obit phase, the inclination of the spacecraft's orbit volition exist raised to near xxx° using repetitive Callisto flybys. The observation opportunities volition complement Galileo observations with respect to Callisto's internal construction and will provide mid- to high-latitude Jupiter temper and magnetosphere measurements over an extended temporal and spatial baseline. During the Callisto flybys of this phase, a sequence similar to the one presented for Europa will be performed at closest approach for some of the Callisto flybys, except for those (nearly three) where the internal construction will be investigated using the radio-science experiment. At the highest inclined orbit, Jupiter'south poles will be visible providing capability for atmospheric dynamics, chemistry and energy balance at polar latitudes. This special observing point allows for a better understanding of magnetosphere–temper coupling, likewise as a more than detailed report of atmospheric properties in both hemispheres using radio science measurements. Similarly, Jovian magnetospheric science will be enhanced since the mission will enable the commencement prolonged studies of this region of the magnetosphere, as well as provide a long temporal baseline study of Jovian aurorae. In add-on, information technology volition provide detailed assay of the field lines and field-aligned current systems well poleward of the main oval. And finally, it will give access to the loftier latitude radio sources in the Jovian magnetosphere.

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Deuterium and the baryonic density of the universe

David Tytler , ... Dan Lubin , in Physics Reports, 2000

Measurement in the atmosphere of Jupiter will give the pre-solar D/H provided (i) most of Jupiter'southward mass was accreted directly from the gas stage, and not from icy planetessimals, which, similar comets today, have excess D/H by fractionation, and (two) the unknown mechanisms which deplete He in Jupiter'south atmosphere practise not depend on mass. Mahaffy et al. [78] discover D/H=2.vi±0.7×x^−v from the Galileo probe mass spectrometer. Feuchtgruber et al. [79] used infrared spectra of the pure rotational lines of Hard disk drive at $37.7 μm$ to measure out D/H=5.v_−1.5 ^+3.5×ten⁻⁵ in Uranus and 6.5_−one.5 ^+ii.5×x^−five in Neptune, which are both sensibly higher because these planets are known to exist primarily composed of ices which have excess D/H.

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Pressure broadening and shift coefficients in the ν1 and ν3 bands of NH3

N. Maaroufi , ... H. Aroui , in Journal of Quantitative Spectroscopy and Radiative Transfer, 2018

1 Introduction

The existence of ammonia gas in the earth atmosphere has been recognized in numerous studies [1–four] showing high concentrations over several space regions affected ecologically. It represents the commencement polyatomic molecule observed in the interstellar area [5] and is i of the components of the Jupiter atmosphere [6].

Ammonia is also an important molecule for fundamental spectroscopy [7–10]. In the infrared region, several laboratory studies have been performed using loftier-resolution spectroscopic techniques to provide line parameters for some fundamental bands of NH₃ [11–20]. For cocky spectroscopic parameters, the authors of Ref. [20] reported a significant discrepancy with HITRAN database [21]. In Refs. [22,23] the authors measured self-broadening coefficients of about 100 lines in the ν_one and ν₃ bands using a divergence-frequency laser spectrometer. The same parameter has been reported in Ref. [24] for the aforementioned bands perturbed by He, Ar, O₂, H₂ and N_ii [24]. In 2004 they reexamine their spectra using a multi-spectrum plumbing equipment process [25]. They retrieved improved values of broadening and shift coefficients as well as line-mixing parameters in the aforementioned bands. Their observed line-shapes exhibit significant deviations from the conventional Voigt profile which have been attributed to some effects such equally line mixing, Dicke narrowing and speed-dependent broadening.

Northward_two and O₂ force per unit area broadening parameters for seven ^RP(J,0) transitions of the ν ₁ +ν ₃ combination band of ammonia have been measured at room temperature using an external cavity tunable diode laser spectrometer [26].

Furthermore, for some molecules with dense spectra, the Lorentz line profile cannot correctly reproduce the experimental spectra [27]. A rigorous treatment of these spectra requires accounting for the line-mixing result. In this context, numerous researches using the first-gild line-mixing profile developed by Rosenkranz [28] have been carried out [27,29,30]. The corresponding line profile is piece of cake to contain in the usual codes since line-mixing contribution is included every bit an additional term to the Lorentz-line shape. This effect tin play an important role in the radiative transfer calculations; it tin can impact the molecular spectroscopy and can affect the atmospheric temperature profiles. It appears for closely spaced transitions (separation of the social club of the inverse of the time between collisions) with high rate inelastic rotational transfer. In the Q-branches of molecules, when the lines overlap, rotational inelastic collisions can transfer intensity from one line to another instead of quenching the absorption. The result is a narrowing of the Q-branch profile.

Using this contour some works accept been published for numerous bands of NH₃ self perturbed and perturbed by numerous gases such every bit He, Ar and H_ii [15,xviii,25,32,33].

In the 3 µm region, the ν₁ and ν_iii bands spectra of Ref. [25] besides show an evident line-mixing effect which has been included in the fits. Henck and Lehman [31] studied cantankerous-relaxation rates of the ^RR(4,4) and ^PP(8,viii) inversion doublets of the ν₃ band of NH₃.

This region arises mainly from the ν₁(A₁), ν₃(E), and 2ν₄(A _ane +E) vibrational bands. Two weaker bands are also present in this region, 4ν2 s (A ₁) and (2ν₂ + ν₄) (Due east), but practise not contribute significantly to the absorption.

To our knowledge, the present work reports the commencement systematic measurements of self-broadening and self-shift coefficients for nigh 510 ro-vibrational transitions in numerous branches of the ν₁ and ν_three bands of NH₃ with accounting for line-mixing effect betwixt lines. The line-mixing coefficients are also retrieved.

The rest of this paper is organized as follows. The next department is devoted to a brief description of the experimental details. Plumbing fixtures procedures will exist outlined in Section 3. The results are retrieved and discussed in Section four. The comparisons with previous works are performed and discussed in Section 5. Conclusion is addressed in Section 6.

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Broadening, shift and narrowing coefficients in the 2ν4 band of NH3 perturbed by O2, N2 and air

Due north. Maaroufi , ... H. Aroui , in Journal of Quantitative Spectroscopy and Radiative Transfer, 2021

1 Introduction

Accurate knowledge of ammonia line parameters is necessary for precise interpretation of loftier-resolution spectra of the Earth's atmosphere and other planetary spaces. Spectroscopic sensors for ammonia are needed for numerous applications including the environs, detection and control of industrial spaces [1], analysis of human breath [two], and recycling of waste product-h2o [3]. Trace detection at ppm levels is often required for these goals [three]. In addition, several laser devices such as rapid-browse absorption [four], wavelength-modulation spectroscopy [v], cavity band-down [2], and photoacoustic spectroscopy [6] are employed to detect NH₃ traces. Also, NH_three is an important molecule for astrophysical applications; this interest arises because large quantities of gaseous ammonia have been detected in Jupiter [seven] and Saturn [8] conferring to this gas to exist a powerful spectroscopic probe of the physico-chemical weather in the infinite of these planets. These applications require precise measurements of NH_iii line spectroscopic parameters performed with appropriate experimental setup and the best line models. Furthermore, the NH_iii absorption in Jupiter's temper, especially, has been shown to be highly sensitive to the choice of spectral absorption line shape model [9].

Several experimental and theoretical studies of the line-widths and line shifts in infrared fundamental bands of NH₃ perturbed by several strange gases were published. Nonetheless spectroscopy of this molecule is still requested, especially for the overtones and combination bands with the aims to improve spectroscopic databases [x–12] which are largely used for fundamental, planetary, and industrial applications. Amid the previous studies, Fabian et al. measured O₂, Northward_two, and Air broadenings for 176 rovibrational lines of NH₃ in the ν₂ band using a loftier-resolution Fourier Transform Spectrometer (FTS) [thirteen]. The broadenings due to the same perturbers have also been measured and analyzed in the ν₄ band, too, with FTS [14,xv]. A prediction of these measurements was achieved with a semi classical model in which the inversion movement of NH₃ is taken into account [16]. Using the same spectrometer, shift coefficients of rovibrational transitions of ammonia perturbed by Due north₂ and O₂ take been reported in Refs. [17] and [18] respectively.

The temperature dependence of pressure level broadening in several branches of the ν_four and 2ν₂ bands of ammonia perturbed by H₂ and Due north_two has been measured using a loftier-resolution FTS [19]. The authors deduced the temperature exponents of the two perturbers. Besides, using an FTS, measurements of collision half-widths of NH_iii-X (X = H₂, Due north_ii, O₂) systems are reported at three temperatures, lower than 296 1000 [20]. Air-broadening are deduced at 296 M and the variation of line-widths with rotational breakthrough numbers J and Yard was studied. In Ref. [21], O₂, N₂, Air-broadening and shift parameters of NH_iii in the ν₂ band were measured and analyzed for five lines from spectra recorded with diode-laser spectrometer. Temperature effect of North_two, O₂, CO₂ and H₂O broadening of Q-branch transitions well-nigh 10.iv μm were studied in Ref. [22] using 2 quantum cascade lasers and a multi-line fitting Voigt contour procedure. N_ii and O_ii pressure broadening parameters for some transitions in the ^RP(J,0) manifold of the ν _one+ν _three combination ring were measured at room temperature using an external crenel tunable diode laser spectrometer [23].

All previous works neglect the Dicke and speed dependent effects [24–26]; and Voigt line-shapes were used to call up the line parameters.

In the iii µm region, pressure level broadening coefficients in the ν_ane and ν₃ bands of NH₃ self-perturbed and perturbed by He, Ar, O₂, N₂, and H_two were obtained by Markov and Pine [27] using spectra recorded with a difference frequency laser spectrometer. In the depression and intermediate pressure range, the authors attributed their fit residual nearly the line center to the Dicke narrowing.

In Ref. [28] the aforementioned authors re-clarify the spectra of Ref. [27] and confront their new results to effectively models, which showed clear evidence for Dicke narrowing and speed-dependent furnishings. A tunable quantum pour laser was used past Owen et al. [29] to measure collisional broadening and Dicke narrowing coefficients of six transitions of NH_three perturbed by N₂ and O₂ in the spectral region well-nigh 1103.46 cm^−ane. Their analyses were based on Voigt and soft-collision Galatry profiles. In our previous contributions in the 2ν₄ band in the three μm spectral region [xxx], nosotros analyzed high-resolution FT spectra with a plumbing fixtures procedure neglecting Dicke and speed-dependent furnishings since these effects are profoundly masked by the strong long-range interactions of NH₃ with a big dipole moment. These effects, which appear in short range interactions near the line centers, arise mostly at low-pressure domains when collisional and Doppler broadening contributions are comparable.

In the present newspaper, the broadening and shifting coefficients of the same ring perturbed by N_ii and O_two were measured at room temperature using spectra recorded with a high-resolution FTS. We used a retrieval program based on Voigt and soft-collision Galatry profiles. The pressure level broadening and shift coefficients besides as Dicke narrowing coefficients were retrieved. Air-broadening parameters were likewise determined bold 79% N₂ and 21% O₂ for the Air composition.

Finally, we compare our results with previous measurements performed in other bands of NH₃ with or without accounting for speed dependence and/or Dicke narrowing [10,xiii–22,28] for some indications of these effects equally well as the vibrational and tunneling dependence of the broadening parameters. Section ii briefly describes the spectrometer and the experimental conditions, presents also the fitting procedures and the uncertainty assay. The measurements of N₂- and O₂-broadening, shift and narrowing coefficients are described in Section 3, which likewise describes the generation of NH₃-Air broadening coefficients. Comparisons with previous measurements are reported in the same section. Conclusions and remarks are provided in Section 4.

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