Search

The article focuses on astronomical observations of planets such as Mars, Jupiter and Saturn. Topics discussed include Mercury transit of the sun being captured in globe imaging and high resolution, relevance of hi-res amateur images for creation of global maps of Jupiter and relevance of 110mm Refractor for lunar eclipse and partial solar eclipse imaging.

The observation of the gaseous giant planets is of high scientific interest. Although they have been the targets of several spacecraft missions, there still remains a need for continuous ground-based observations. As their atmospheres present fast dynamic environments on varied timescales, the availability of time at professional telescopes is neither uniform nor of sufficient duration to assess temporal changes. On the other hand, numerous amateurs with small telescopes (with typical apertures of 15-40 cm) and modern hardware and software equipment can monitor these changes daily (within the 360-900nm wavelength range).Amateur observers are able to trace the structure and the evolution of atmospheric features, such as major planetary-scale disturbances, vortices, and storms.Their observations provide a continuous record and it is not uncommon to trigger professional observations in cases of important events, such as sudden onset of global changes, storms and celestial impacts. For example, the continuous amateur monitoring has led to the discovery of fireballs in Jupiter's atmosphere, which provide information not only on Jupiter's gravitational influence but also on the properties and populations of the impactors. Photometric monitoring of stellar occultations by the planets can reveal spatial/temporal variability in their atmospheric structure. Co-ordination and communication between professionals and amateurs is therefore important. We present examples of such collaborations that: (i) engage systematic multi-wavelength observations and databases, (ii) examine the variability of cloud features over timescales from days to decades, (iii) provide, by ground-based professional and amateur observations, the necessary spatial and temporal resolution of features that will be studied by the interplanetary mission Juno, (iv) investigate video observations of Jupiter to identify impacts of small objects, (v) carry out stellar-occultation campaigns. [ABSTRACT FROM AUTHOR]

Examination continues in detail for the use of controlled fusion for high-energy, crewed-missions to the outer planets at significant continual acceleration (>0.01go) . Transit times to Jupiter measured in a few months, delivering 200 t of payload, appear possible, but require the use of advanced fuels, e.g., D\-He^3 , to reduce the excessive burden of radiator mass needed to process the heat of fusion neutrons. Such advanced reactions, however, need plasma temperatures in excess of 100 keV, so adiabatic compression is invoked to match the desired final state to much more modest initial temperature values. This compression would be achieved by stabilized implosion of liquid metal liners, as demonstrated decades ago in the Linus program at the Naval Research Laboratory. Distinctions are drawn between the present propulsion design options and the earlier Linus fusion power reactor based on D-T fuel. [ABSTRACT FROM PUBLISHER]

Context. We investigate the grain opacity κgr in the atmosphere (outer radiative zone) of forming planets. This is important for the observed planetary mass-radius relationship since κgr affects the primordial H/He envelope mass of low-mass planets and the critical core mass of giant planets. Aims. The goal of this study is to derive a simple analytical model for κgr and to explore its implications for the atmospheric structure and resulting gas accretion rate. Methods. Our model is based on the comparison of the timescales of the most important microphysical processes. We consider grain settling in the Stokes and Epstein drag regime, growth by Brownian motion coagulation and diffierential settling, grain evaporation in hot layers, and grain advection due to the contraction of the envelope.With these timescales and the assumption of a radially constant grain flux, we derive the typical grain size, abundance, and opacity. Results.We find that the dominating growth process is diffierential settling. In this regime, κgr has a simple functional form; it is given as 27Q/8Hρ in the Epstein regime in the outer atmosphere and as 2Q/Hρ for Stokes drag in the deeper layers. Grain growth leads to a typical radial structure of κgr with high ISM-like values in the outer layers but a strong decrease towards the deeper parts where κgr becomes so low that the grain-free molecular opacities take over. Conclusions. In agreement with earlier results, we find that κgr is typically much lower than in the ISM. In retrospect, this suggests that classical giant planet formation models should have considered the grain-free case to be as equally meaningful as the full ISM opacity case. The equations also show that a higher dust input in the top layers does not strongly increase κgr. This has two important implications. First, for the formation of giant planet cores via pebbles, there could be the adverse e ect that pebbles tend to increase the grain input high in the atmosphere because of ablation. This could in principle increase the opacity, making giant planet formation difficult. Our study indicates that this potentially adverse e ect is not important. Second, it means that a higher stellar [Fe/H] which presumably leads to a higher surface density of planetesimals only favors giant planet formation without being detrimental to it because of an increased κgr. This corroborates the result that core accretion can explain the observed increase of the giant planet frequency with stellar [Fe/H]. [ABSTRACT FROM AUTHOR]

Super-Jupiter-mass planets should form only beyond the snow line of host stars. However, the core accretion theory of planetary formation does not predict super-Jupiters forming around low-mass hosts. We present a discovery of a 3.9 ± 1.2 MJup mass planet orbiting the 0.59 ± 0.17 M☼ star using the gravitational microlensing method. During the event, the projected separation of the planet and the star is 3.9 ± 1.0 AU, i.e., the planet is significantly further from the host star than the snow line. This is the fourth such planet discovered using the microlensing technique and challenges the core accretion theory. [ABSTRACT FROM AUTHOR]

The planet HD 209458 b is one of the most well studied hot-Jupiter exoplanets. The upper atmosphere of this planet has been observed through ultraviolet/optical transit observations with Hi observation of the exosphere revealing atmospheric escape. At lower altitudes just below the thermosphere, detailed observations of the Na I absorption line has revealed an atmospheric thermal inversion. This thermal structure is rising toward high temperatures at high altitudes, as predicted by models of the thermosphere, and could reach ~10 000 K at the exobase level. Here, we report new near ultraviolet Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) observations of atmospheric absorptions during the planetary transit of HD 209458 b. We report absorption in atomic magnesium (Mg I), while no signal has been detected in the lines of singly ionized magnesium (Mg II). We measure the Mg I atmospheric absorption to be 6.2± 2.9% in the velocity range from -62 to -19 km s-1. The detection of atomic magnesium in the planetary upper atmosphere at a distance of several planetary radii gives a first view into the transition region between the thermosphere and the exobase, where atmospheric escape takes place. We estimate the electronic densities needed to compensate for the photo-ionization by dielectronic recombination of Mg+ to be in the range of 108-109 cm-3. Our finding is in excellent agreement with model predictions at altitudes of several planetary radii. We observe Mg i atoms escaping the planet, with a maximum radial velocity (in the stellar rest frame) of -60 km s-1. Because magnesium is much heavier than hydrogen, the escape of this species confirms previous studies that the planet's atmosphere is undergoing hydrodynamic escape. We compare our observations to a numerical model that takes the stellar radiation pressure on the Mgi atoms into account. We find that the Mg I atoms must be present at up to ~7.5 planetari radii altitude and estimate an Mg I escape rate of ~3 × 107 g s-1. Compared to previous evaluations of the escape rate of H I atoms, this evaluation is compatible with a magnesium abundance roughly solar. A hint of absorption, detected at low level of significance, during the post-transit observations, could be interpreted as a Mg I cometary-like tail. If true, the estimate of the absorption by Mg I would be increased to a higher value of about 8.8 ± 2.1%. [ABSTRACT FROM AUTHOR]

Exoplanet WASP-14b is a highly irradiated, transiting hot Jupiter. Joshi et al. calculate an equilibrium temperature (Teq) of 1866 K for zero albedo and reemission from the entire planet, a mass of 7.3 ± 0.5 Jupiter masses (MJ), and a radius of 1.28 ± 0.08 Jupiter radii (RJ). Its mean density of 4.6 g cm-3 is one of the highest known for planets with periods less than three days. We obtained three secondary eclipse light curves with the Spitzer Space Telescope. The eclipse depths from the best jointly fit model are 0.224% ± 0.018% at 4.5 μm and 0.181% ± 0.022% at 8.0 μm. The corresponding brightness temperatures are 2212 ± 94 K and 1590 ± 116 K. A slight ambiguity between systematic models suggests a conservative 3.6 μm eclipse depth of 0.19% ± 0.01% and brightness temperature of 2242 ± 55 K. Although extremely irradiated, WASP-14b does not show any distinct evidence of a thermal inversion. In addition, the present data nominally favor models with day-night energy redistribution less than ∼30%. The current data are generally consistent with oxygen-rich as well as carbon-rich compositions, although an oxygen-rich composition provides a marginally better fit. We confirm a significant eccentricity of e = 0.087 ± 0.002 and refine other orbital parameters. [ABSTRACT FROM AUTHOR]

We present a ground-based optical transmission spectrum of the inflated sub-Jupiter-mass planet WASP-6b. The spectrum was measured in 20 spectral channels from 480 nm to 860 nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the Inamori-Magellan Areal Camera and Spectrograph on the Baade Telescope at Las Campanas Observatory. We model systematic effects on the observed light curves using principal component analysis on the comparison stars and allow for the presence of short and long memory correlation structure in our Monte Carlo Markov Chain analysis of the transit light curves for WASP-6. The measured transmission spectrum presents a general trend of decreasing apparent planetary size with wavelength and lacks evidence for broad spectral features of Na and K predicted by clear atmosphere models. The spectrum is consistent with that expected for scattering that is more efficient in the blue, as could be caused by hazes or condensates in the atmosphere of WASP-6b. WASP-6b therefore appears to be yet another massive exoplanet with evidence for a mostly featureless transmission spectrum, underscoring the importance that hazes and condensates can have in determining the transmission spectra of exoplanets. [ABSTRACT FROM AUTHOR]

We present a Hubble Space Telescope Wide Field Camera-3 (WFC3) transmission spectrum for the transiting exoplanet HAT-P-12b. This warm (1000 K) sub-Saturn-mass planet has a smaller mass and a lower temperature than the hot Jupiters that have been studied so far. We find that the planet's measured transmission spectrum lacks the expected water absorption feature for a hydrogen-dominated atmosphere and is instead best described by a model with high-altitude clouds. Using a frequentist hypothesis testing procedure, we can rule out a hydrogen-dominated cloud-free atmosphere to 4.9σ. When combined with other recent WFC3 studies, our observations suggest that clouds may be common in exoplanetary atmospheres. [ABSTRACT FROM AUTHOR]

Directly imaged exoplanets are unexplored laboratories for the application of the spectral and temperature retrieval method, where the chemistry and composition of their atmospheres are inferred from inverse modeling of the available data. As a pilot study, we focus on the extrasolar gas giant HR 8799b, for which more than 50 data points are available. We upgrade our non-linear optimal estimation retrieval method to include a phenomenological model of clouds that requires the cloud optical depth and monodisperse particle size to be specified. Previous studies have focused on forward models with assumed values of the exoplanetary properties; there is no consensus on the best-fit values of the radius, mass, surface gravity, and effective temperature of HR 8799b. We show that cloud-free models produce reasonable fits to the data if the atmosphere is of super-solar metallicity and non-solar elemental abundances. Intermediate cloudy models with moderate values of the cloud optical depth and micron-sized particles provide an equally reasonable fit to the data and require a lower mean molecular weight. We report our best-fit values for the radius, mass, surface gravity, and effective temperature of HR 8799b. The mean molecular weight is about 3.8, while the carbon-to-oxygen ratio is about unity due to the prevalence of carbon monoxide. Our study emphasizes the need for robust claims about the nature of an exoplanetary atmosphere to be based on analyses involving both photometry and spectroscopy and inferred from beyond a few photometric data points, such as are typically reported for hot Jupiters. [ABSTRACT FROM AUTHOR]

A Jupiter-family comet, 17P/Holmes, underwent outbursts in 1892 and 2007. In particular, the 2007 outburst is known as the greatest outburst over the past century. However, little is known about the activity before the outburst because it was unpredicted. In addition, the time evolution of the nuclear physical status has not been systematically studied. Here, we study the activity of 17P/Holmes before and after the 2007 outburst through optical and mid-infrared observations. We found that the nucleus was highly depleted in its near-surface icy component before the outburst but that it became activated after the 2007 outburst. Assuming a conventional 1 μm sized grain model, we derived a surface fractional active area of 0.58% ± 0.14% before the outburst whereas the area was enlarged by a factor of ∼50 after the 2007 outburst. We also found that large (⩾1 mm) particles could be dominant in the dust tail observed around aphelion. Based on the size of the particles, the dust production rate was ≳170 kg s–1 at a heliocentric distance of rh = 4.1 AU, suggesting that the nucleus was still active around the aphelion passage. The nucleus color was similar to that of the dust particles and average for a Jupiter-family comet but different from that of most Kuiper Belt objects, implying that color may be inherent to icy bodies in the solar system. On the basis of these results, we concluded that more than 76 m of surface material was blown off by the 2007 outburst. [ABSTRACT FROM AUTHOR]

Infrared light curves of transiting hot Jupiters present a trend in which the atmospheres of the hottest planets are less efficient at redistributing the stellar energy absorbed on their daysides—and thus have a larger day-night temperature contrast—than colder planets. To this day, no predictive atmospheric model has been published that identifies which dynamical mechanisms determine the atmospheric heat redistribution efficiency on tidally locked exoplanets. Here we present a shallow-water model of the atmospheric dynamics on synchronously rotating planets that explains why heat redistribution efficiency drops as stellar insolation rises. Our model shows that planets with weak friction and weak irradiation exhibit a banded zonal flow with minimal day-night temperature differences, while models with strong irradiation and/or strong friction exhibit a day-night flow pattern with order-unity fractional day-night temperature differences. To interpret the model, we develop a scaling theory which shows that the timescale for gravity waves to propagate horizontally over planetary scales, τwave, plays a dominant role in controlling the transition from small to large temperature contrasts. This implies that heat redistribution is governed by a wave-like process, similar to the one responsible for the weak temperature gradients in the Earth's tropics. When atmospheric drag can be neglected, the transition from small to large day-night temperature contrasts occurs when , where τrad is the radiative relaxation time and Ω is the planetary rotation frequency. Alternatively, this transition criterion can be expressed as τrad ∼ τvert, where τvert is the timescale for a fluid parcel to move vertically over the difference in day-night thickness. These results subsume the more widely used timescale comparison for estimating heat redistribution efficiency between τrad and the horizontal day-night advection timescale, τadv. Only because τadv ∼ τvert for hot Jupiters does the commonly assumed timescale comparison between τrad and τadv yield approximately correct predictions for the heat redistribution efficiency. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Juno Mission to Jupiter meets planetary protection requirements. [•] Analyses include bioburden reduction due to Jovian environments. [•] Analysis of hypothetical impacts shows a high likelihood of sterilization. [Copyright &y& Elsevier]

We present a new version of our code for modeling the atmospheric circulation on gaseous exoplanets, now employing a "double-gray" radiative transfer scheme, which self-consistently solves for fluxes and heating throughout the atmosphere, including the emerging (observable) infrared flux. We separate the radiation into infrared and optical components, each with its own absorption coefficient, and solve standard two-stream radiative transfer equations. We use a constant optical absorption coefficient, while the infrared coefficient can scale as a power law with pressure; however, for simplicity, the results shown in this paper use a constant infrared coefficient. Here we describe our new code in detail and demonstrate its utility by presenting a generic hot Jupiter model. We discuss issues related to modeling the deepest pressures of the atmosphere and describe our use of the diffusion approximation for radiative fluxes at high optical depths. In addition, we present new models using a simple form for magnetic drag on the atmosphere. We calculate emitted thermal phase curves and find that our drag-free model has the brightest region of the atmosphere offset by ~12° from the substellar point and a minimum flux that is 17% of the maximum, while the model with the strongest magnetic drag has an offset of only ~2° and a ratio of 13%. Finally, we calculate rates of numerical loss of kinetic energy at ~15% for every model except for our strong-drag model, where there is no measurable loss; we speculate that this is due to the much decreased wind speeds in that model. [ABSTRACT FROM AUTHOR]

An important class of formation theories for hot Jupiters involves the excitation of extreme orbital eccentricity (e = 0.99 or even larger) followed by tidal dissipation at periastron passage that eventually circularizes the planetary orbit at a period less than 10 days. In a steady state, this mechanism requires the existence of a significant population of super-eccentric (e > 0.9) migrating Jupiters with long orbital periods and periastron distances of only a few stellar radii. For these super-eccentric planets, the periastron is fixed due to conservation of orbital angular momentum and the energy dissipated per orbit is constant, implying that the rate of change in semi-major axis a is a ∝ a1/2 and consequently the number distribution satisfies d N/d log a ∝ a1/2. If this formation process produces most hot Jupiters, Kepler should detect several super-eccentric migrating progenitors of hot Jupiters, allowing for a test of high-eccentricity migration scenarios. [ABSTRACT FROM AUTHOR]

We report the discovery of HAT-P-17b,c, a multi-planet system with an inner transiting planet in a short-period, eccentric orbit and an outer planet in a 4.4 yr, nearly circular orbit. The inner planet, HAT-P-17b, transits the bright V = 10.54 early K dwarf star GSC 2717-00417, with an orbital period P = 10.338523 ± 0.000009 days, orbital eccentricity e = 0.342 ± 0.006, transit epoch Tc = 2454801.16943 ± 0.00020 (BJD: barycentric Julian dates throughout the paper are calculated from Coordinated Universal Time (UTC)), and transit duration 0.1690±0.0009 days. HAT-P-17b has a mass of 0.534±0.018 MJ and radius of 1.010±0.029 RJ yielding a mean density of 0.64 ± 0.05 g cm-3. This planet has a relatively low equilibrium temperature in the range 780-927 K, making it an attractive target for follow-up spectroscopic studies. The outer planet, HAT-P-17c, has a significantly +0.18 longer orbital period P2 = 1610 ± 20 days and a minimum mass m2 sin i2 = 1.31-0.15+0.18 MJ. The orbital inclination of HAT-P-17c is unknown as transits have not been observed and may not be present. The host star has a mass of 0.86 ± 0.04 Mʘ, radius of 0.84 ± 0.02 Rʘ, effective temperature 5246 ± 80 K, and metallicity [Fe/H] = 0.00 ± 0.08. HAT-P-17 is the second multi-planet system detected from ground-based transit surveys. [ABSTRACT FROM AUTHOR]

New monthly latitude measurements of the northern and southern boundaries of Jupiter's North Equatorial Belt (NEB) are reported for 1995 to 2011. The latitudinal width oscillated with a period of about 4½ years during this time. This is similar to the behavior between 1896 and 1953 as reported in the literature. One new finding is that the width changed over a few months. The barge, a dark and almost rectangular-shaped spot, is the most well observed feature in the NEB. It was decided to investigate what affect the changing NEB had on the number and drift rate of barges. There is little correlation between belt width and the number of NEB barges. There is also little correlation between belt width and the average drift rate of NEB barges. [ABSTRACT FROM AUTHOR]

Discusses observations of ions and electrons of probable Jovian origin upstream of Jupiter made by the Energetic Particle Composition Instrument (EPAC) on the Ulysses spacecraft. Observations made after a corotating interplanetary particle event; Low fluxes of energetic particles; Relationships of fluxes.

Describes the investigation of the ion composition in the Jovian environment, measured using the Solar Wind Ion Composition Spectrometer on the Ulysses spacecraft. Observation of hot tenuous plasma; Thermally different components; Solar wind particles; Presence of ions from Jupiter's ionosphere.

Reports on several of the new discoveries made concerning the hot plasma environment during the Ulysses flyby of Jupiter. Extended magnetosphere; Composition of heavy ion population; Characteristics of ion fluxes in day-side magnetosphere; Characteristics of dusk-side, high-latitude region; Measurement of intense particle beams which may produce auroras in Jupiter's polar ice caps.

Presents an overview of preliminary scientific findings from the Ulysses spacecraft's February 1992 flyby of Jupiter. Primary objective of mission; Observation of Jovian magnetosphere; Results of observations; Aspects of Jovian encounter common to all investigations.

Jupiter's main ring shows vertical corrugations reminiscent of those recently detected in the rings of Saturn. The Galileo spacecraft imaged a pair of superimposed ripple patterns in 1996 and again in 2000. These patterns behave as two independent spirals, each winding up at a rate defined by Jupiter's gravity field. The dominant pattern originated between July and October 1994, when the entire ring was tilted by about 2 kilometers. We associate this with the Shoemaker-Levy 9 impacts of July 1994. New Horizons images still show this pattern 13 years later and suggest that subsequent events may also have tilted the ring. Impacts by comets or their dust streams are regular occurrences in planetary rings, altering them in ways that remain detectable decades later. [ABSTRACT FROM AUTHOR]

The article discusses the findings of a study published in the periodical "Nature" related to bizarre geometric arrangements of storms on Jupiter's poles and mentions that each storm arrayed around one cyclone over the north and south poles, unlike any storm formation seen in the universe.

Reports on the detection of sodium to distances beyond about 400 RJ near Jupiter. Shows that ground-based imaging techniques can provide information about distant planetary magnetospheres.

Describes the findings of the Ulysses dust detector during its Jupiter flyby. Impacts recorded; Origins of particles causing impacts; Particles' retrograde orbits; Results of Ulysses' pass through intense dust stream; Implications of dust flux measurements.

The article offers information on report about the planet Jupiter from 2013-2014. Topics discussed include the disturbance of the planet in 2012 wherein it had undergone northern upheaval and had finished in 2013, the development of pale reddish color in the North Tropical domain in the planet in November 2013 which was a prominent anticyclonic white oval since 1997, and the aggravation of the long-term shrinking trend of the Great Red Spot (GRS) of the Jupiter in 2012.

The article discusses a report published in "Physical Review Letters" by planetary scientists Hugh Wilson and Burkhard Militzer on simulations that found that the core of the planet Jupiter is eroding due to the dissolution of magnesium oxide (MgO) in hydrogen-helium liquids of the mantle.

It is shown that compact bodies project out strands of concentrated dark matter filaments, henceforth simply called hairs. These hairs are a consequence of the fine-grained stream structure of dark matter halos, and as such constitute a new physical prediction of ΛCDM. Using both an analytical model of planetary density and numerical simulations utilizing the Fast Accurate Integrand Renormalization algorithm (a fast geodesics calculator described below) with realistic planetary density inputs, dark matter streams moving through a compact body are shown to produce hugely magnified dark matter densities along the stream velocity axis passing through the center of the body. Typical hair density enhancements are 107 for Earth and 108 for Jupiter. The largest enhancements occur for particles streaming through the core of the body that are mostly focused at a single point called the root of the hair. For the Earth, the root is located at about 106 km from the planetary center with a density enhancement of around 109 while for a gas giant like Jupiter, the root is located at around 105 km with an enhancement of around 1011. Beyond the root, the hair density precisely reflects the density layers of the body, providing a direct probe of planetary interiors. [ABSTRACT FROM AUTHOR]

Detailed characterization of exoplanets has begun to yield measurements of their atmospheric properties that constrain the planets’ origins and evolution. For example, past observations of the dayside emission spectrum of the hot Jupiter WASP-12b indicated that its atmosphere has a high carbon-to-oxygen ratio (C/O > 1), suggesting it had a different formation pathway than is commonly assumed for giant planets. Here we report a precise near-infrared transmission spectrum for WASP-12b based on six transit observations with the Hubble Space Telescope/Wide Field Camera 3. We bin the data in 13 spectrophotometric light curves from 0.84 to 1.67 μm and measure the transit depths to a median precision of 51 ppm. We retrieve the atmospheric properties using the transmission spectrum and find strong evidence for water absorption (7σ confidence). This detection marks the first high-confidence, spectroscopic identification of a molecule in the atmosphere of WASP-12b. The retrieved 1 σ water volume mixing ratio is between 10−5 and 10−2, which is consistent with C/O > 1 to within 2σ. However, we also introduce a new retrieval parameterization that fits for C/O and metallicity under the assumption of chemical equilibrium. With this approach, we constrain C/O to at 1σ and rule out a carbon-rich atmosphere composition (C/O > 1) at >3σ confidence. Further observations and modeling of the planet’s global thermal structure and dynamics would aid in resolving the tension between our inferred C/O and previous constraints. Our findings highlight the importance of obtaining high-precision data with multiple observing techniques in order to obtain robust constraints on the chemistry and physics of exoplanet atmospheres. [ABSTRACT FROM AUTHOR]

Deducing the cloud cover and its temporal evolution from the observed planetary spectra and phase curves can give us major insight into the atmospheric dynamics. In this paper, we present Aeolus, a Markov chain Monte Carlo code that maps the structure of brown dwarf and other ultracool atmospheres. We validated Aeolus on a set of unique Jupiter Hubble Space Telescope (HST) light curves. Aeolus accurately retrieves the properties of the major features of the Jovian atmosphere, such as the Great Red Spot and a major 5 μm hot spot. Aeolus is the first mapping code validated on actual observations of a giant planet over a full rotational period. For this study, we applied Aeolus to J- and H-band HST light curves of 2MASS J21392676+0220226 and 2MASS J0136565+093347. Aeolus retrieves three spots at the top of the atmosphere (per observational wavelength) of these two brown dwarfs, with a surface coverage of 21% ± 3% and 20.3% ± 1.5%, respectively. The Jupiter HST light curves will be publicly available via ADS/VIZIR. [ABSTRACT FROM AUTHOR]

The primordial internal structures of gas giant planets are unknown. Often giant planets are modeled under the assumption that they are adiabatic, convective, and homogeneously mixed, but this is not necessarily correct. In this work, we present the first self-consistent calculation of convective transport of both heat and material as the planets evolve. We examine how planetary evolution depends on the initial composition and its distribution, whether the internal structure changes with time, and if so, how it affects the evolution. We consider various primordial distributions, different compositions, and different mixing efficiencies and follow the distribution of heavy elements in a Jupiter-mass planet as it evolves. We show that a heavy-element core cannot be eroded by convection if there is a sharp compositional change at the core-envelope boundary. If the heavy elements are initially distributed within the planet according to some compositional gradient, mixing occurs in the outer regions resulting in a compositionally homogeneous outer envelope. Mixing of heavy materials that are injected in a convective gaseous envelope are found to mix efficiently. Our work demonstrates that the primordial internal structure of a giant planet plays a substantial role in determining its long-term evolution and that giant planets can have non-adiabatic interiors. These results emphasize the importance of coupling formation, evolution, and internal structure models of giant planets self-consistently. [ABSTRACT FROM AUTHOR]

We present high angular resolution Submillimeter Array observations of the outbursting Jupiter family comet 17P/Holmes on 2007 October 26-29, achieving a spatial resolution of 2.″5, or ∼3000 km at the comet distance. The observations resulted in detections of the rotational lines CO 3-2, HCN 4-3, H13CN 4-3, CS 7-6, H2CO 31, 2-21, 1, H2S 22, 0-21, 1, and multiple CH3OH lines, along with the associated dust continuum at 221 and 349 GHz. The continuum has a spectral index of 2.7 ± 0.3, slightly steeper than blackbody emission from large dust particles. From the imaging data, we identify two components in the molecular emission. One component is characterized by a relatively broad line width (∼1 km s–1 FWHM) exhibiting a symmetric outgassing pattern with respect to the nucleus position. The second component has a narrower line width (<0.5 km s–1 FWHM) with the line center redshifted by 0.1-0.2 km s–1 (cometocentric frame), and shows a velocity shift across the nucleus position with the position angle gradually changing from 66° to 30° within the four days of observations. We determine distinctly different CO/HCN ratios for each of the components. For the broad-line component we find CO/HCN < 7, while in the narrow-line component, CO/HCN = 40 ± 5. We hypothesize that the narrow-line component originates from the ice grain halo found in near-nucleus photometry, believed to be created by sublimating recently released ice grains around the nucleus during the outburst. In this interpretation, the high CO/HCN ratio of this component reflects the more pristine volatile composition of nucleus material released in the outburst. [ABSTRACT FROM AUTHOR]