Its volcanic plumes and lava flows produce large surface changes and paint the surface in various subtle shades of yellow, red, white, black, and green, largely due to allotropes and compounds of sulfur. Io has both a patchy but relatively large atmosphere and an ionosphere, and there is considerable interaction of Io with the jovian magnetic field. Io (/Ëaɪ.oÊ/), or Jupiter I, is the innermost and third-largest of the four Galilean moons of the planet Jupiter. The plasma in this doughnut-shaped ring of ionized sulfur, oxygen, sodium, and chlorine originates when neutral atoms in the "cloud" surrounding Io are ionized and carried along by the Jovian magnetosphere. But this seems far too thin, because at this calculated air density there would be too little air to cause 7 tons fuel usage to hold orbit. The resonant orbit also helps to maintain Io's distance from Jupiter; otherwise tides raised on Jupiter would cause Io to slowly spiral outward from its parent planet. The height above the surface of the ray at its closest approach to Earth is called the tangent height, zT. E is the evaporation rate (flux of water vapor per unit area), and L is the latent heat of vaporization. [93][94], Based on their experience with the ancient surfaces of the Moon, Mars, and Mercury, scientists expected to see numerous impact craters in Voyager 1's first images of Io. Other shield volcanoes with much shallower slopes are inferred from the morphology of several of Io's volcanoes, where thin flows radiate out from a central patera, such as at Ra Patera. The Io Volcano Observer (IVO) is a proposal to NASA, currently in Phase A, for a low-cost, Discovery-class mission that would launch in January 2029. One consequence is that Io is the most volcanic object known anywhere, with lava flows, erupting with plumes of sulfurous material, and a changing atmosphere of noxious gases. Copyright © 2021 Elsevier B.V. or its licensors or contributors. What is the density of air? Atmosphere: In 1995, the Galileo mission revealed that Europa has a thin atmosphere composed mostly of molecular oxygen (O 2 ). At low heights (250 – 850 km) above Earth’s surface the atmospheric density and Earth’s albedo plays the most important role. Obtaining useful solutions with the statistical methods commonly used for high-speed atmospheric flows requires enormous computational resources. D.N. [24] The latter is the basis of the English adjectival form, Ionian. Over a 20-hour period, these particles spread out from Io to form a banana-shaped, neutral cloud that can reach as far as six Jovian radii from Io, either inside Io's orbit and ahead of it or outside Io's orbit and behind it. [63] JUICE has a launch scheduled for 2022, with arrival at Jupiter planned for October 2029. Most agricultural animals, like humans, also have the capacity to rid themselves of excess heat by means of evaporation. These particles originate in Io's upper atmosphere and are excited by collisions with ions in the plasma torus (discussed below) and by other processes into filling Io's Hill sphere, which is the region where Io's gravity is dominant over Jupiter's. Large landslide deposits are common at the base of Ionian mountains, suggesting that mass wasting is the primary form of degradation. These measurements can be achieved by a highly sensitive accelerometer with resolution up to 10− 9 ms− 2 and to get it as a vector, i.e. [47] Without this forced eccentricity, Io's orbit would circularize through tidal dissipation, leading to a geologically less active world. [10][11][12] This extreme geologic activity is the result of tidal heating from friction generated within Io's interior as it is pulled between Jupiter and the other Galilean moonsâEuropa, Ganymede and Callisto. For example, the leading edge of the Prometheus flow moved 75 to 95 km (47 to 59 mi) between Voyager in 1979 and the first Galileo observations in 1996. [120] The compressive stresses leading to mountain formation are the result of subsidence from the continuous burial of volcanic materials. Aerodynamic forces directly depend on the air density. [105] Whatever the formation mechanism, the morphology and distribution of many paterae suggest that these features are structurally controlled, with at least half bounded by faults or mountains. Such porosity allows efficient subsurface cold trapping of atmospheric gases which tends to keep ambient surface pressures very low. It will vary, sometimes by a large factor. Several initiatives are examining the time-rate of change for this parameter, but not looking at the variable area, and its effect in this combined factor. daily—just the daily values are interpolated. [128] Much of the sulfur dioxide in Io's atmosphere is sustained by sunlight-driven sublimation of SO2 frozen on the surface. If you pass in zero, you should get the sea level pressure. Some of this material escapes Io's gravitational pull and goes into orbit around Jupiter. All 3-hourly values are ignored. The gust factor is the ratio of the gust speed to the steady wind speed. Io's surface is dotted with volcanic depressions known as paterae which generally have flat floors bounded by steep walls. Therefore it is much more simple than usual models and on its base the analytical theory of Earth’s artificial satellite motion was accomplished. Note that the scales are the same, the relative effect of different models and solar data options are about the same, and any transient effects quickly disappear as the effect of drag overwhelms the contributions. The neutral clouds of sodium, oxygen, and sulfur extend from the corona to distances of many times the radius of Jupiter. Io is in a 2:1 mean-motion orbital resonance with Europa and a 4:1 mean-motion orbital resonance with Ganymede, completing two orbits of Jupiter for every one orbit completed by Europa, and four orbits for every one completed by Ganymede. It is the fourth-largest moon in the Solar System, has the highest density of all of them, and has the lowest amount of water (by atomic ratio) of any known astronomical object in the Solar System. Another problem, the interval over which wind speeds are averaged, varies from country to country. [70] The collision process that excites these particles also occasionally provides sodium ions in the plasma torus with an electron, removing those new "fast" neutrals from the torus. Aurorae usually occur near the magnetic poles of planets, but Io's are brightest near its equator. The codes should treat all F10.7 measurements at the time the measurement is actually taken. Although many factors influence this ratio, one can develop approximations for the gust factor as a function of steady wind speed. Fig. [23] The name has two competing stems in Latin: ĪŠand (rarely) ĪÅn. P.S. Plumes formed in this manner are among the largest observed at Io, forming red rings more than 1,000 km (620 mi) in diameter. Elaine S. Oran, Jay P. Boris, in Encyclopedia of Physical Science and Technology (Third Edition), 2002. The left-hand graph shows the variations by simply selecting different atmospheric models. [125][126] The thin Ionian atmosphere also means any future landing probes sent to investigate Io will not need to be encased in an aeroshell-style heatshield, but instead require retrothrusters for a soft landing. A previous study indicates that a gust must have a duration such that its magnitude is about eight times the downwind dimension of a structure in order to produce a force on the structure commensurate with the gust speed. [125][126] The low pressure limits the atmosphere's effect on the surface, except for temporarily redistributing sulfur dioxide from frost-rich to frost-poor areas, and to expand the size of plume deposit rings when plume material re-enters the thicker dayside atmosphere. Like JUICE, Europa Clipper will not perform any flybys of Io, but distant volcano monitoring is likely. Smaller structures will be sensitive to shorter-duration gusts. So far, sodium has not been detected on Io's surface or plumes, but its existence is inferred because of its detection in the cloud. In 2013, we assumed “counting people” was a solved problem. Vallado [16] conducted a series of tests to determine the variability of different atmospheric models for a given satellite using a single flight dynamics program, and the differences resulting from the diverse treatment of the input solar weather data. While Juno's highly inclined orbit keeps the spacecraft out of the orbital planes of Io and the other major moons of Jupiter, its orbit has been precessing so that its close approach point to Jupiter is at increasing latitudes and the ascending node of its orbit is getting closer to Jupiter with each orbit. Air density, like air pressure, decreases with increasing altitude. The cloud is populated by sodium atoms escaping Io at about 2.6 km s−1. Regardless, Marius's first recorded observation came from 29 December 1609 in the Julian calendar, which equates to 8 January 1610 in the Gregorian calendar, which Galileo used. In spite of the large volume of gas released through volcanic activity, Io's atmosphere is extremely thin, less than one millionth as dense as Earth's atmosphere. ", "Geologic mapping of the Chaac-Camaxtli region of Io from Galileo imaging data", "Juno mission captures images of volcanic plumes on Jupiter's moon Io", "Imaging of volcanic activity on Jupiter's moon Io by Galileo during the Galileo Europa Mission and the Galileo Millennium Mission", "New estimates for Io eruption temperatures: Implications for the interior", "Galileo Imaging of Atmospheric Emissions from Io", "Origin of mountains on Io by thrust faulting and large-scale mass movements", "Chaos on Io: A model for formation of mountain blocks by crustal heating, melting, and tilting", 10.1130/0091-7613(2001)029<0103:COIAMF>2.0.CO;2, "Convection in Io's asthenosphere: Redistribution of nonuniform tidal heating by mean flows", "Landform degradation and slope processes on Io: The Galileo view", "Mid-infrared detection of large longitudinal asymmetries in Io's, "SwRI Space Scientists Observe Io's Atmospheric Collapse During Eclipse", "The collapse of Io's primary atmosphere in Jupiter eclipse", "Io's Equatorial Spots: Morphology of Neutral UV Emissions", Paul Schenk's 3D images and flyover videos of Io and other outer solar system satellites, The Exploration of the Earth's Magnetosphere, The Conundrum Posed by Io's Minimum Surface Temperatures, https://en.wikipedia.org/w/index.php?title=Io_(moon)&oldid=1011427379#Atmosphere, Wikipedia articles with WorldCat-VIAF identifiers, ÐелаÑÑÑÐºÐ°Ñ (ÑаÑаÑкевÑÑа)â, Srpskohrvatski / ÑÑпÑкоÑ
ÑваÑÑки, Creative Commons Attribution-ShareAlike License, This page was last edited on 10 March 2021, at 20:53. Europa Clipper is a planned NASA mission to the Jovian system focused on Jupiter's moon Europa. This result was spectacularly confirmed as at least nine active volcanoes were observed by Voyager 1. Galileo observed the effects of a major eruption at Pillan Patera and confirmed that volcanic eruptions are composed of silicate magmas with magnesium-rich mafic and ultramafic compositions. However, in addition as mentioned TD-88 is much easier to use and more precise for longer orbit prediction (Ref. The bright blue glows mark the sites of dense plumes of volcanic vapor and may represent the locations where Io is electrically connected to Jupiter via a flux tube. An additional comment is necessary. Gas in Io's atmosphere is stripped by Jupiter's magnetosphere, escaping to either the neutral cloud that surrounds Io, or the Io plasma torus, a ring of ionized particles that shares Io's orbit but co-rotates with the magnetosphere of Jupiter. [28] Named, bright albedo regions use the term regio. Compositional mapping and Io's high density suggest that Io contains little to no water, though small pockets of water ice or hydrated minerals have been tentatively identified, most notably on the northwest flank of the mountain Gish Bar Mons. The following recommendations are set forth. [75] The dust in these discrete streams travels away from Jupiter at speeds upwards of several hundred kilometres per second, has an average particle size of 10 μm, and consists primarily of sodium chloride. Minimum solar flux periods (F10.7 ∼ 70) will show little difference. [56], The Juno spacecraft was launched in 2011 and entered orbit around Jupiter on July 5, 2016. [38], The first spacecraft to pass by Io were the Pioneer 10 and 11 probes on 3 December 1973 and 2 December 1974, respectively. It appears as a diffuse yellowish emission produced by scattered light from volcanic plumes and Io's lit crescent. (2007), Outside astronomy, "Ionian" would likely be misunderstood as referring to, the first measurement of the speed of light, "Planet and Satellite Names and Discoverers", "Planetary Satellite Physical Parameters", "Interior composition, structure and dynamics of the Galilean satellites", "This World Is a Simmering Hellscape. [83] Models of its orbit suggest that the amount of tidal heating within Io changes with time; however, the current amount of tidal dissipation is consistent with the observed heat flow. Short- and long-ranged atomic or molecular interactions in the liquid itself become more anisotropic for small systems with large surface areas. The radiance measured by the satellite is given by. This makes standardization of atmospheric models especially difficult. Gaposchkin [. Table 1. The primary goal of these encounters will be to improve our understanding of Io's gravity field using doppler tracking and to image Io's surface to look for surface changes since Io was last seen up-close in 2007. From the surface of Io, Jupiter would subtend an arc of 19.5°, making Jupiter appear 39 times the apparent diameter of Earth's Moon. [45] Analysis of other Voyager 1 images showed nine such plumes scattered across the surface, proving that Io was volcanically active. These forces we call non-gravitational, they are highly time-dependent and uncertainty in orbit determination thanks to them is in hundreds of meters. [104] Unlike similar features on Earth and Mars, these depressions generally do not lie at the peak of shield volcanoes and are normally larger, with an average diameter of 41 km (25 mi), the largest being Loki Patera at 202 km (126 mi). Figure 18-3. ): r ''' Determine absolute (pressure-adjusted) airmass from relative airmass and pressure. Basic fluid-dynamic problems in MEMS involve developing reliable experimental diagnostics of such small systems. Some material does escape Io, forming a corona and neutral clouds, and the Io torus further away. As a by-product of this activity, sulfur, sulfur dioxide gas and silicate pyroclastic material (like ash) are blown up to 200 km (120 mi) into space, producing large, umbrella-shaped plumes, painting the surrounding terrain in red, black, and white, and providing material for Io's patchy atmosphere and Jupiter's extensive magnetosphere. It also changes with variation in temperature or humidity. This ability to generate heat in a subsurface ocean increases the chance of life on bodies like Europa and Enceladus. ... sales@density.io +1 888 990-2253 . The location of Io and its auroral footprint with respect to Earth and Jupiter has a strong influence on Jovian radio emissions from our vantage point: when Io is visible, radio signals from Jupiter increase considerably. The cubic splines routine discussed in Vallado and Kelso [17] should be used to interpolate geomagnetic indices. The maximum atmospheric pressure on Io ranges from 3.3 à 10â5 to 3 à 10â4 pascals (Pa) or 0.3 to 3 nbar, spatially seen on Io's anti-Jupiter hemisphere and along the equator, and temporally in the early afternoon when the temperature of surface frost peaks. Because the atmosphere comes from its volcanoes, the air of Io is made primarily of sulphur. Many sources state that the current atmospheric models introduce about a 15% error in the determination of atmospheric drag effects on a satellite. Electrostatic forces originating at surfaces and imperfections on surfaces are increasingly important. [40] The Pioneers also revealed the presence of a thin atmosphere and intense radiation belts near the orbit of Io. The Jovian magnetic field lines that do get past Io's ionosphere also induce an electric current, which in turn creates an induced magnetic field within Io's interior. Plume deposits on Io are often colored red or white depending on the amount of sulfur and sulfur dioxide in the plume. There are discrete values for which ap and kp exist in the daily data. Particles from this auroral interaction darken the Jovian polar regions at visible wavelengths. Once the particles from the atmosphere get into the magnetosphere, they create a donut-shaped cloud of material around Io. [70] Unlike the particles in the neutral cloud, these particles co-rotate with Jupiter's magnetosphere, revolving around Jupiter at 74 km/s. [38][70] The Juno mission, currently in orbit around Jupiter, should help to shed light on these processes. [130] A sublimation-driven atmosphere is also consistent with observations that Io's atmosphere is densest over the anti-Jupiter hemisphere, where SO2 frost is most abundant, and is densest when Io is closer to the Sun. In eqn [2], Rn is the net gain of heat from radiation; M is the net gain of heat from metabolism; C is the loss of sensible heat to air by convection; LE is the loss of latent heat by evaporation of water; G is the loss of heat to ground and vegetation by conduction.