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Sample records for proto-gas giant planets

  1. Giant Planets

    NASA Astrophysics Data System (ADS)

    Lunine, J. I.

    Beyond the inner solar system's terrestrial planets, with their compact orbits and rock -metal compositions, lies the realm of the outer solar system and the giant planets. Here the distance between planets jumps by an order of magnitude relative to the spacing of the terrestrial planets, and the masses of the giants are one to two orders of magnitude greater than Venus and Earth - the largest terrestrial bodies. Composition changes as well, since the giant planets are largely gaseous, with inferred admixtures of ice, rock, and metal, while the terrestrial planets are essentially pure rock and metal. The giant planets have many more moons than do the terrestrial planets, and the range of magnetic field strengths is larger in the outer solar system. It is the giant planets that sport rings, ranging from the magnificent ones around Saturn to the variable ring arcs of Neptune. Were it not for the fact that only Earth supports abundant life (with life possibly existing, but not proved to exist, in the martian crust and liquid water regions underneath the ice of Jupiter's moon Europa), the terrestrial planets would pale in interest next to the giant planets for any extraterrestrial visitor.

  2. MIGRATION AND GROWTH OF PROTOPLANETARY EMBRYOS. II. EMERGENCE OF PROTO-GAS-GIANT CORES VERSUS SUPER EARTH PROGENITORS

    SciTech Connect

    Liu, Beibei; Zhang, Xiaojia; Lin, Douglas N. C.; Aarseth, Sverre J.

    2015-01-01

    Nearly 15%-20% of solar type stars contain one or more gas giant planets. According to the core-accretion scenario, the acquisition of their gaseous envelope must be preceded by the formation of super-critical cores with masses 10 times or larger than that of the Earth. It is natural to link the formation probability of gas giant planets with the supply of gases and solids in their natal disks. However, a much richer population of super Earths suggests that (1) there is no shortage of planetary building block material, (2) a gas giant's growth barrier is probably associated with whether it can merge into super-critical cores, and (3) super Earths are probably failed cores that did not attain sufficient mass to initiate efficient accretion of gas before it is severely depleted. Here we construct a model based on the hypothesis that protoplanetary embryos migrated extensively before they were assembled into bona fide planets. We construct a Hermite-Embryo code based on a unified viscous-irradiation disk model and a prescription for the embryo-disk tidal interaction. This code is used to simulate the convergent migration of embryos, and their close encounters and coagulation. Around the progenitors of solar-type stars, the progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high (≳ 10{sup –7} M {sub ☉} yr{sup –1}) mass accretion rates, whereas systems of super Earths (failed cores) are more likely to emerge out of natal disks with modest mass accretion rates, due to the mean motion resonance barrier and retention efficiency.

  3. Imaging Extrasolar Giant Planets

    NASA Astrophysics Data System (ADS)

    Bowler, Brendan P.

    2016-10-01

    High-contrast adaptive optics (AO) imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order AO systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young (≈5-300 Myr) stars spanning stellar masses between 0.1 and 3.0 M ⊙, the overall occurrence rate of 5-13 M Jup companions at orbital distances of 30-300 au is {0.6}-0.5+0.7 % assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically significant trend in planet frequency with host mass: giant planets are found around {2.8}-2.3+3.7 % of BA stars, <4.1% of FGK stars, and <3.9% of M dwarfs. Looking forward, extreme AO systems and the next generation of ground- and space-based telescopes with smaller inner working angles and deeper detection limits will increase the pace of discovery to ultimately map the demographics, composition, evolution, and origin of planets spanning a broad range of masses and ages.

  4. Formation of giant planets

    NASA Astrophysics Data System (ADS)

    Magni, G.; Coradini, A.

    2003-04-01

    In this presentation we address the problem of the formation of giant planets and their regular satellites. We study in particular the problem of formation of the Jupiter System comparing the results of the model with the present characteristics of the system, in order to identify what are those better represented by our approach. In fact here, using a 3-D hydro-dynamical code, we study the modalities of gas accretion onto a solid core, believed to be the seed from which Jupiter started. To do that we have modelled three main regions: the central planet, a turbulent accretion disk surrounding it and an extended region from which the gas is collected. In the extended region we treat the gas as a frictionless fluid. Our main goal is to identify what are the characteristics of the planet during its growth and the physical parameters affecting its growth at the expenses of the nebular gas present in the feeding zone. Moreover we want to understand what are the thermodynamical parameters characterizing the gas captured by the planet and swirling around it. Finally, we check if a disk can be formed in prograde rotation around the planet and if this disk can survive the final phases of the planet formation. Due to the interaction between the accreting planet and the disk it has been necessary to develop a complete model of the Jupiter’s structure. In fact the radiation emitted by the growing planet heats up the surrounding gas. In turn the planet’s thermodynamic structure depend on the mass accretion rate onto it. When the accretion is rapid, shock waves in the gas are formed close to the planet. This region cannot be safely treated by a numerical code; for this reason we have developed a semi-analytically model of a a turbulent accretion disk to be considered as transition between the planet and the surrounding disk.

  5. Giant impacts on giant planets

    NASA Astrophysics Data System (ADS)

    de Pater, Imke

    2014-10-01

    The 2009 impact and recent superbolides on Jupiter caught the world by surprise and cast doubt on impactor flux estimates for the outer solar system. Enhanced amateur planetary imaging techniques yield both high spatial resolution (enabling the 2009 impact debris field detection) and rapid frame rates (enabling the 2010/2012 impact flash detections and lightcurve measurements).We propose a ToO program to image future impacts on Jupiter and Saturn. To remove the possibility of impact cloud non-detections, the program will be triggered only if an existing impact debris field is seen, an object on a collision course with Jupiter or Saturn is discovered, or an impact light curve is measured with an estimated total energy large enough to generate an impact cloud in a giant planet atmosphere (10^20 J).HST provides the only way to image these events in the ultraviolet, providing information on aerosol altitudes and on smaller particles that are less visible to ground-based infrared observations. High-resolution imaging with proper timing (not achievable from the ground) is required to measure precisely both the velocity fields of impact sites and the optical spectrum of impact debris. HST observations of past impacts on Jupiter have also served both as cornerstones of science investigations at other wavelengths and as vehicles for effective public outreach.Large outer solar system impacts are governed by the same physics as in the terrestrial events that dominate the impact threat to humans. Studying the behavior of impactors of various sizes and compositions, as they enter the atmosphere at varying angles and speeds, will better quantify terrestrial impact hazards.

  6. Giant impacts on giant planets

    NASA Astrophysics Data System (ADS)

    de Pater, Imke

    2013-10-01

    The 2009 impact and recent superbolides on Jupiter caught the world by surprise and cast doubt on impactor flux estimates for the outer solar system. Enhanced amateur planetary imaging techniques yield both high spatial resolution {enabling the 2009 impact debris field detection} and rapid frame rates {enabling the 2010/2012 impact flash detections and lightcurve measurements}.We propose a ToO program to image future impacts on Jupiter and Saturn. To remove the possibility of impact cloud non-detections, the program will be triggered only if an existing impact debris field is seen, an object on a collision course with Jupiter or Saturn is discovered, or an impact light curve is measured with an estimated total energy large enough to generate an impact cloud in a giant planet atmosphere {10^20 J}.HST provides the only way to image these events in the ultraviolet, providing information on aerosol altitudes and on smaller particles that are less visible to ground-based infrared observations. High-resolution imaging with proper timing {not achievable from the ground} is required to measure precisely both the velocity fields of impact sites and the optical spectrum of impact debris. HST observations of past impacts on Jupiter have also served both as cornerstones of science investigations at other wavelengths and as vehicles for effective public outreach.Large outer solar system impacts are governed by the same physics as in the terrestrial events that dominate the impact threat to humans. Studying the behavior of impactors of various sizes and compositions, as they enter the atmosphere at varying angles and speeds, will better quantify terrestrial impact hazards.

  7. Atmospheres of Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2006-01-01

    The next decade will almost certainly see the direct imaging of extrasolar giant planets around nearby stars. Unlike purely radial velocity detections, direct imaging will open the door to characterizing the atmosphere and interiors of extrasola planets and ultimately provide clues on their formation and evolution through time. This process has already begun for the transiting planets, placing new constraints on their atmospheric structure, composition, and evolution. Indeed the key to understanding giant planet detectability, interpreting spectra, and constraining effective temperature and hence evolution-is the atmosphere. I will review the universe of extrasolar giant planet models, focusing on what we have already learned from modeling and what we will likely be able to learn from the first generation of direct detection data. In addition to these theoretical considerations, I will review the observations and interpretation of the - transiting hot Jupiters. These objects provide a test of our ability to model exotic atmospheres and challenge our current understanding of giant planet evolution.

  8. The Metallicity of Giant Planets

    NASA Astrophysics Data System (ADS)

    Thorngren, Daniel P.; Fortney, Jonathan

    2015-12-01

    Unique clues about the formation processes of giant planets can be found in their bulk compositions. Transiting planets provide us with bulk density determinations that can then be compared to models of planetary structure and evolution, to deduce planet bulk metallicities. At a given mass, denser planets have a higher mass fraction of metals. However, the unknown hot Jupiter "radius inflation" mechanism leads to under-dense planets that severely biases this work. Here we look at cooler transiting gas giants (Teff < 1000 K), which do not exhibit the radius inflation effect seen in their warmer cousins. We identified 40 such planets between 20 M_Earth and 20 M_Jup from the literature and used evolution models to determine their bulk heavy-element ("metal") mass. Several important trends are apparent. We see that all planets have at least ~10 M_Earth of metals, and that the mass of metal correlates strongly with the total mass of the planet. The heavy-element mass goes as the square root of the total mass. Both findings are consistent with the core accretion model. We also examined the effect of the parent star metallicity [Fe/H], finding that planets around high-metallicity stars are more likely to have large amounts of metal, but the relation appears weaker than previous studies with smaller sample sizes had suggested. We also looked for connections between bulk composition and planetary orbital parameters and stellar parameters, but saw no pattern, which is also an important result. This work can be directly compared to current and future outputs from planet formation models, including population synthesis.

  9. The Giant Planet Jupiter

    NASA Astrophysics Data System (ADS)

    Rogers, John H.

    2009-07-01

    Part I. Observing Jupiter: 1. Observations from Earth; 2. Observations from spacecraft; Part II. The Visible Structure of the Atmosphere: 3. Horizontal structure: belts, currents, spots and storms; 4. Vertical structure: colours and clouds; Part III. The Observational Record of the Atmosphere: 5. The Polar Region; 6. North North Temperate Regions (57°N to 35°N); 7. North Temperate Region (35°N to 23°N); 8. North Tropical Region (23°N to 9°N); 9. Equatorial Region (9°N to 9°S); 10. South Tropical Region (9°S to 27°S); 11. South Temperate Region (27°S to 37°S); 12. South South Temperate Region (37°S to 53°S); Part IV: The Physics and Chemistry of the Atmosphere: 13. Possible large-scale and long-term patterns; 14. The dynamics of individual spots; 15. Theoretical models of the atmosphere; 16. The composition of the planet; Part V. The Electrodynamic Environment of Jupiter: 17. Lights in the Jovian night; 18. The magnetosphere and radiation belts; Part VI. The Satellites: 19. The inner satellites and the ring; 20. The Galilean satellites; 21. Io; 22. Europa; 23. Ganymede; 24. Callisto; 25. The outer satellites; Appendices: 1. Measurement of longitude; 2. Measurement of latitude; 3. Lists of apparitions and published reports; 4. Bibliography (The planet); 5. Bibliography (The magnetosphere and satellites); Index.

  10. Tides in Giant Planets

    NASA Astrophysics Data System (ADS)

    Stevenson, David J.

    2015-11-01

    The arrival of Juno at Jupiter in less than a year necessitates analysis of what we can learn from the gravitational signal due to tides raised on the planet by satellites (especially Io but also Europa). In the existing literature, there is extensive work on static tidal theory (the response of the planet to a tidal potential whose time dependence is ignored) and this is what is usually quoted when people refer to tidal Love numbers. If this were correct then there would be almost no new information content in the measurement of tidally induced gravity field, since the perturbation is of the same kind as the response to rotation (i.e., the measurement of J2, a well-known quantity). However, tides are dynamic (that is, k2 is frequency dependent) and so there is new information in the frequency dependent part. There is also (highly important) information in the imaginary part (more commonly expressed as tidal Q) but there is no prospect of direct detection of this by Juno since that quadrature signal is so small. The difference between what we expect to measure and what we can already calculate directly from J2 is easily shown to be of order the square of tidal frequency over the lowest order normal mode frequency, and thus of order 10%. However, the governing equations are not simple (not separable) because of the Coriolis force. An approximate solution has been obtained for the n =1 polytrope showing that the correction to k2 is even smaller, typically a few percent, because the tidal frequency is not very different from twice the rotation frequency. Moreover, it is not highly sensitive to structure in standard models. However, the deep interior of the planet may be stably stratified because of a compositional gradient and this modifies the tidal flow amplitude, changing the dynamic k2 but not the static k2. This raises the exciting possibility that we can use the determination of k2 to set bounds on the extent of static stability, if any. There is also the slight

  11. Giant Planets in Open Clusters

    NASA Astrophysics Data System (ADS)

    Quinn, S. N.; White, R. J.; Latham, D. W.

    2015-10-01

    Two decades after the discovery of 51 Peg b, more than 200 hot Jupiters have now been confirmed, but the details of their inward migration remain uncertain. While it is widely accepted that short period giant planets could not have formed in situ, several different mechanisms (e.g., Type II migration, planet-planet scattering, Kozai-Lidov cycles) may contribute to shrinking planetary orbits, and the relative importance of each is not well-constrained. Migration through the gas disk is expected to preserve circular, coplanar orbits and must occur quickly (within ˜ 10 Myr), whereas multi-body processes should initially excite eccentricities and inclinations and may take hundreds of millions of years. Subsequent evolution of the system (e.g., orbital circularization and inclination damping via tidal interaction with the host star) may obscure these differences, so observing hot Jupiters soon after migration occurs can constrain the importance of each mechanism. Fortunately, the well-characterized stars in young and adolescent open clusters (with known ages and compositions) provide natural laboratories for such studies, and recent surveys have begun to take advantage of this opportunity. We present a review of the discoveries in this emerging realm of exoplanet science, discuss the constraints they provide for giant planet formation and migration, and reflect on the future direction of the field.

  12. How Giant Planets Shape the Characteristics of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas; Quintana, Elisa V.

    2016-01-01

    The giant planets in the Solar System likely played a defining role in shaping the properties of the Earth and other terrestrial planets during their formation. Observations from the Kepler spacecraft indicate that terrestrial planets are highly abundant. However, there are hints that giant planets a few AU from their stars are not ubiquitous. It therefore seems reasonable to assume that many terrestrial planets lack a Jupiter-like companion. We use a recently developed, state-of-the-art N-body model that allows for collisional fragmentation to perform hundreds of numerical simulations of the final stages of terrestrial planet formation around a Sun-like star -- with and without giant outer planets. We quantify the effects that outer giant planet companions have on collisions and the planet accretion process. We focus on Earth-analogs that form in each system and explore how giant planets influence the relative frequency of giant impacts occurring at late times and the delivery of volitiles. This work has important implications for determining the frequency of habitable planets.

  13. The Effect of Giant Planets on Terrestrial Planet Formation

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas; Quintana, Elisa

    2015-12-01

    The giant planets in the Solar System likely played a defining role in shaping the properties of the Earth and other terrestrial planets during their formation. Observations from the Kepler spacecraft indicate that terrestrial planets are highly abundant. However, there are hints that giant planets a few AU from their stars are relatively uncommon based on long baseline radial velocity searches. It therefore seems reasonable to assume that many terrestrial planets lack a Jupiter-like companion. We use a recently developed, state-of-the-art N-body model that allows for collisional fragmentation to perform hundreds of numerical simulations of the final stages of terrestrial planet formation around a Sun-like star -- with and without giant outer planets. We quantify the effects that outer giant planet companions have on collisions and the planet accretion process. We focus on Earth-analogs that form in each system and explore how giant planets influence the relative frequency of giant impacts occurring at late times.

  14. Formation of Giant Planets and Brown Dwarves

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2003-01-01

    According to the prevailing core instability model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant planet cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Models predict that rocky planets should form in orbit about most stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. Ongoing theoretical modeling of accretion of giant planet atmospheres, as well as observations of protoplanetary disks, will help decide this issue. Observations of extrasolar planets around main sequence stars can only provide a lower limit on giant planet formation frequency . This is because after giant planets form, gravitational interactions with material within the protoplanetary disk may cause them to migrat inwards and be lost to the central star. The core instability model can only produce planets greater than a few jovian masses within protoplanetary disks that are more viscous than most such disks are believed to be. Thus, few brown dwarves (objects massive enough to undergo substantial deuterium fusion, estimated to occur above approximately 13 jovian masses) are likely to be formed in this manner. Most brown dwarves, as well as an unknown number of free-floating objects of planetary mass, are probably formed as are stars, by the collapse of extended gas/dust clouds into more compact objects.

  15. The Giant Planet Satellite Exospheres

    NASA Technical Reports Server (NTRS)

    McGrath, Melissa A.

    2014-01-01

    Exospheres are relatively common in the outer solar system among the moons of the gas giant planets. They span the range from very tenuous, surface-bounded exospheres (e.g., Rhea, Dione) to quite robust exospheres with exobase above the surface (e.g., lo, Triton), and include many intermediate cases (e.g., Europa, Ganymede, Enceladus). The exospheres of these moons exhibit an interesting variety of sources, from surface sputtering, to frost sublimation, to active plumes, and also well illustrate another common characteristic of the outer planet satellite exospheres, namely, that the primary species often exists both as a gas in atmosphere, and a condensate (frost or ice) on the surface. As described by Yelle et al. (1995) for Triton, "The interchange of matter between gas and solid phases on these bodies has profound effects on the physical state of the surface and the structure of the atmosphere." A brief overview of the exospheres of the outer planet satellites will be presented, including an inter-comparison of these satellites exospheres with each other, and with the exospheres of the Moon and Mercury.

  16. Electrodynamics on extrasolar giant planets

    SciTech Connect

    Koskinen, T. T.; Yelle, R. V.; Lavvas, P.; Cho, J. Y-K.

    2014-11-20

    Strong ionization on close-in extrasolar giant planets (EGPs) suggests that their atmospheres may be affected by ion drag and resistive heating arising from wind-driven electrodynamics. Recent models of ion drag on these planets, however, are based on thermal ionization only and do not include the upper atmosphere above the 1 mbar level. These models are also based on simplified equations of resistive magnetohydrodynamics that are not always valid in extrasolar planet atmospheres. We show that photoionization dominates over thermal ionization over much of the dayside atmosphere above the 100 mbar level, creating an upper ionosphere dominated by ionization of H and He and a lower ionosphere dominated by ionization of metals such as Na, K, and Mg. The resulting dayside electron densities on close-in exoplanets are higher than those encountered in any planetary ionosphere of the solar system, and the conductivities are comparable to the chromosphere of the Sun. Based on these results and assumed magnetic fields, we constrain the conductivity regimes on close-in EGPs and use a generalized Ohm's law to study the basic effects of electrodynamics in their atmospheres. We find that ion drag is important above the 10 mbar level where it can also significantly alter the energy balance through resistive heating. Due to frequent collisions of the electrons and ions with the neutral atmosphere, however, ion drag is largely negligible in the lower atmosphere below the 10 mbar level for a reasonable range of planetary magnetic moments. We find that the atmospheric conductivity decreases by several orders of magnitude in the night side of tidally locked planets, leading to a potentially interesting large-scale dichotomy in electrodynamics between the day and night sides. A combined approach that relies on UV observations of the upper atmosphere, phase curve and Doppler measurements of global dynamics, and visual transit observations to probe the alkali metals can potentially be

  17. YOUNG SOLAR SYSTEM's FIFTH GIANT PLANET?

    SciTech Connect

    Nesvorny, David

    2011-12-15

    Studies of solar system formation suggest that the solar system's giant planets formed and migrated in the protoplanetary disk to reach the resonant orbits with all planets inside {approx}15 AU from the Sun. After the gas disk's dispersal, Uranus and Neptune were likely scattered by the gas giants, and approached their current orbits while dispersing the transplanetary disk of planetesimals, whose remains survived to this time in the region known as the Kuiper Belt. Here we performed N-body integrations of the scattering phase between giant planets in an attempt to determine which initial states are plausible. We found that the dynamical simulations starting with a resonant system of four giant planets have a low success rate in matching the present orbits of giant planets and various other constraints (e.g., survival of the terrestrial planets). The dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, and leads to final systems with fewer than four planets. Several initial states stand out in that they show a relatively large likelihood of success in matching the constraints. Some of the statistically best results were obtained when assuming that the solar system initially had five giant planets and one ice giant, with the mass comparable to that of Uranus and Neptune, and which was ejected to interstellar space by Jupiter. This possibility appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, which indicates that planet ejection should be common.

  18. Exotic Earths: forming habitable worlds with giant planet migration.

    PubMed

    Raymond, Sean N; Mandell, Avi M; Sigurdsson, Steinn

    2006-09-01

    Close-in giant planets (e.g., "hot Jupiters") are thought to form far from their host stars and migrate inward, through the terrestrial planet zone, via torques with a massive gaseous disk. Here we simulate terrestrial planet growth during and after giant planet migration. Several-Earth-mass planets also form interior to the migrating jovian planet, analogous to recently discovered "hot Earths." Very-water-rich, Earth-mass planets form from surviving material outside the giant planet's orbit, often in the habitable zone and with low orbital eccentricities. More than a third of the known systems of giant planets may harbor Earth-like planets.

  19. Exotic Earths: forming habitable worlds with giant planet migration.

    PubMed

    Raymond, Sean N; Mandell, Avi M; Sigurdsson, Steinn

    2006-09-01

    Close-in giant planets (e.g., "hot Jupiters") are thought to form far from their host stars and migrate inward, through the terrestrial planet zone, via torques with a massive gaseous disk. Here we simulate terrestrial planet growth during and after giant planet migration. Several-Earth-mass planets also form interior to the migrating jovian planet, analogous to recently discovered "hot Earths." Very-water-rich, Earth-mass planets form from surviving material outside the giant planet's orbit, often in the habitable zone and with low orbital eccentricities. More than a third of the known systems of giant planets may harbor Earth-like planets. PMID:16960000

  20. The Effect of Giant Planets on Habitable Planet Formation

    NASA Astrophysics Data System (ADS)

    Quintana, Elisa V.; Barclay, Thomas

    2016-06-01

    The giant planets in the Solar System likely played a large role in shaping the properties of the Earth during its formation. To explore their effects, we numerically model the growth of Earth-like planets around Sun-like stars with and without Jupiter and Saturn analog companions. Employing state-of-the-art dynamical formation models that allow both accretion and collisional fragmentation, we perform hundreds of simulations and quantify the specific impact energies of all collisions that lead to the formation of an Earth-analog. Our model tracks the bulk compositions and water abundances in the cores and mantles of the growing protoplanets to constrain the types of giant planet configurations that allow the formation of habitable planets. We find significant differences in the collisional histories and bulk compositions of the final planets formed in the presence of different giant planet configurations. Exoplanet surveys like Kepler hint at a paucity of Jupiter analogs, thus these analyses have important implications for determining the frequency of habitable planets and also support target selection for future exoplanet characterization missions.

  1. THE ORBITAL EVOLUTION OF GAS GIANT PLANETS AROUND GIANT STARS

    SciTech Connect

    Villaver, Eva; Livio, Mario E-mail: mlivio@stsci.ed

    2009-11-01

    Recent surveys have revealed a lack of close-in planets around evolved stars more massive than 1.2 M{sub sun}. Such planets are common around solar-mass stars. We have calculated the orbital evolution of planets around stars with a range of initial masses, and have shown how planetary orbits are affected by the evolution of the stars all the way to the tip of the red giant branch. We find that tidal interaction can lead to the engulfment of close-in planets by evolved stars. The engulfment is more efficient for more-massive planets and less-massive stars. These results may explain the observed semimajor axis distribution of planets around evolved stars with masses larger than 1.5 M{sub sun}. Our results also suggest that massive planets may form more efficiently around intermediate-mass stars.

  2. Thermal escape from extrasolar giant planets

    PubMed Central

    Koskinen, Tommi T.; Lavvas, Panayotis; Harris, Matthew J.; Yelle, Roger V.

    2014-01-01

    The detection of hot atomic hydrogen and heavy atoms and ions at high altitudes around close-in extrasolar giant planets (EGPs) such as HD209458b implies that these planets have hot and rapidly escaping atmospheres that extend to several planetary radii. These characteristics, however, cannot be generalized to all close-in EGPs. The thermal escape mechanism and mass loss rate from EGPs depend on a complex interplay between photochemistry and radiative transfer driven by the stellar UV radiation. In this study, we explore how these processes change under different levels of irradiation on giant planets with different characteristics. We confirm that there are two distinct regimes of thermal escape from EGPs, and that the transition between these regimes is relatively sharp. Our results have implications for thermal mass loss rates from different EGPs that we discuss in the context of currently known planets and the detectability of their upper atmospheres. PMID:24664923

  3. Thermal escape from extrasolar giant planets.

    PubMed

    Koskinen, Tommi T; Lavvas, Panayotis; Harris, Matthew J; Yelle, Roger V

    2014-04-28

    The detection of hot atomic hydrogen and heavy atoms and ions at high altitudes around close-in extrasolar giant planets (EGPs) such as HD209458b implies that these planets have hot and rapidly escaping atmospheres that extend to several planetary radii. These characteristics, however, cannot be generalized to all close-in EGPs. The thermal escape mechanism and mass loss rate from EGPs depend on a complex interplay between photochemistry and radiative transfer driven by the stellar UV radiation. In this study, we explore how these processes change under different levels of irradiation on giant planets with different characteristics. We confirm that there are two distinct regimes of thermal escape from EGPs, and that the transition between these regimes is relatively sharp. Our results have implications for thermal mass loss rates from different EGPs that we discuss in the context of currently known planets and the detectability of their upper atmospheres. PMID:24664923

  4. Thermal escape from extrasolar giant planets.

    PubMed

    Koskinen, Tommi T; Lavvas, Panayotis; Harris, Matthew J; Yelle, Roger V

    2014-04-28

    The detection of hot atomic hydrogen and heavy atoms and ions at high altitudes around close-in extrasolar giant planets (EGPs) such as HD209458b implies that these planets have hot and rapidly escaping atmospheres that extend to several planetary radii. These characteristics, however, cannot be generalized to all close-in EGPs. The thermal escape mechanism and mass loss rate from EGPs depend on a complex interplay between photochemistry and radiative transfer driven by the stellar UV radiation. In this study, we explore how these processes change under different levels of irradiation on giant planets with different characteristics. We confirm that there are two distinct regimes of thermal escape from EGPs, and that the transition between these regimes is relatively sharp. Our results have implications for thermal mass loss rates from different EGPs that we discuss in the context of currently known planets and the detectability of their upper atmospheres.

  5. The properties of planets around giant stars

    NASA Astrophysics Data System (ADS)

    Jones, M. I.; Jenkins, J. S.; Bluhm, P.; Rojo, P.; Melo, C. H. F.

    2014-06-01

    Context. More than 50 exoplanets have been found around giant stars, revealing different properties when compared to planets orbiting solar-type stars. In particular, they are super-Jupiters and are not found orbiting interior to ~0.5 AU. Aims: We are conducting a radial velocity study of a sample of 166 giant stars aimed at studying the population of close-in planets orbiting giant stars and how their orbital and physical properties are influenced by the post-MS evolution of the host star. Methods: We have collected multiepoch spectra for all of the targets in our sample. We have computed precision radial velocities from FECH/CHIRON and FEROS spectra, using the I2 cell technique and the simultaneous calibration method, respectively. Results: We present the discovery of a massive planet around the giant star HIP 105854. The best Keplerian fit to the data leads to an orbital distance of 0.81 ± 0.03 AU, an eccentricity of 0.02 ± 0.03 and a projected mass of 8.2 ± 0.2 MJ. With the addition of this new planet discovery, we performed a detailed analysis of the orbital properties and mass distribution of the planets orbiting giant stars. We show that there is an overabundance of planets around giant stars with a ~ 0.5 - 0.9 AU, which might be attributed to tidal decay. Additionally, these planets are significantly more massive than those around MS and subgiant stars, suggesting that they grow via accretion either from the stellar wind or by mass transfer from the host star. Finally, we show that planets around evolved stars have lower orbital eccentricities than those orbiting solar-type stars, which suggests that they are either formed in different conditions or that their orbits are efficiently circularized by interactions with the host star. Based on observations collected at La Silla - Paranal Observatory under programs IDs 085.C-0557, 087.C.0476, 089.C-0524 and 090.C-0345.The RV Table is only available at the CDS via anonymous ftp to http

  6. Optical Spectra of Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Hubeny, Ivan; Sudarsky, David; Burrows, Adam

    2004-01-01

    The flux distribution of a planet relative to its host star is a critical quantity for planning space observatories to detect and characterize extrasolar giant planets (EGP's). In this paper, we present optical planet-star contrasts of Jupiter-mass planets as a function of stellar type, orbital distance, and planetary cloud characteristics. As originally shown by Sudarsky et al. (2000, 2003), the phaseaveraged brightness of an EGP does not necessarily decrease monotonically with greater orbital distance because of changes in its albedo and absorption spectrum at lower temperatures. We apply our results to Eclipse, a 1.8-m optical telescope + coronograph to be proposed as a NASA Discovery mission later this year.

  7. Characterizing Cool Giant Planets in Reflected Light

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2016-01-01

    While the James Webb Space Telescope will detect and characterize extrasolar planets by transit and direct imaging, a new generation of telescopes will be required to detect and characterize extrasolar planets by reflected light imaging. NASA's WFIRST space telescope, now in development, will image dozens of cool giant planets at optical wavelengths and will obtain spectra for several of the best and brightest targets. This mission will pave the way for the detection and characterization of terrestrial planets by the planned LUVOIR or HabEx space telescopes. In my presentation I will discuss the challenges that arise in the interpretation of direct imaging data and present the results of our group's effort to develop methods for maximizing the science yield from these planned missions.

  8. Overcoming Migration during Giant Planet Formation

    NASA Astrophysics Data System (ADS)

    Thommes, Edward W.; Nilsson, Leif; Murray, Norman

    2007-02-01

    In the core accretion model, gas giant formation is a race between growth and migration; for a core to become a Jovian planet, it must accrete its envelope before it spirals into the host star. We use a multizone numerical model to extend our previous investigation of the ``window of opportunity'' for gas giant formation within a disk. When the collision cross section enhancement due to core atmospheres is taken into account, we find that a broad range of protoplanetary disks possess such a window.

  9. Atmospheric models for post- giant impact planets

    NASA Astrophysics Data System (ADS)

    Lupu, R.; Zahnle, K. J.; Marley, M. S.; Schaefer, L. K.; Fegley, B.; Morley, C.; Cahoy, K.; Freedman, R. S.; Fortney, J. J.

    2013-12-01

    The final assembly of terrestrial planets is now universally thought to have occurred through a series of giant impacts, such as Earth's own Moon-forming impact. These collisions take place over a time interval of about 100 million years, during which time it takes at least 10 collisions between planets to make a Venus or an Earth. In the aftermath of one of these collisions the surviving planet is hot, and can remain hot for millions of years. During this phase of accretion, the proto-terrestrial planet may have a dense steam atmosphere, that will affect both the cooling of the planet and our ability to detect it. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting of vaporized rock material. The atmospheric chemistry is computed self-consistently for atmospheres in equilibrium with hot surfaces, with compositions reflecting either the bulk silicate Earth (BSE, which includes the crust, mantle, atmosphere and oceans) or Earth's continental crust (CC). These two cases allow us to examine differences in atmospheres formed by outgassing of silica-rich (felsic) rocks - like the Earth's continental crust - and MgO- and FeO-rich (mafic) rocks - like the BSE. Studies of detrital zircons from Jack Hills, Australia, show that the continental crust existed 164 million years after the formation of the solar system, in which case the material vaporized in a giant impact should likely reflect the CC composition. However, if at the time of impact the surface of the planet does not yet exhibit the formation of continents, then the BSE case becomes relevant. We compute atmospheric profiles for surface temperatures ranging from 1000 to 2200 K, surface pressures of 10 and 100 bar, and surface gravities of 10 and 30 m/s^2. We account for all major molecular and atomic opacity sources, including collision-induced absorption, to derive the atmospheric structure and compute

  10. DO GIANT PLANETS SURVIVE TYPE II MIGRATION?

    SciTech Connect

    Hasegawa, Yasuhiro; Ida, Shigeru E-mail: ida@geo.titech.ac.jp

    2013-09-10

    Planetary migration is one of the most serious problems to systematically understand the observations of exoplanets. We clarify that the theoretically predicted type II, migration (like type I migration) is too fast, by developing detailed analytical arguments in which the timescale of type II migration is compared with the disk lifetime. In the disk-dominated regime, the type II migration timescale is characterized by a local viscous diffusion timescale, while the disk lifetime is characterized by a global diffusion timescale that is much longer than the local one. Even in the planet-dominated regime where the inertia of the planet mass reduces the migration speed, the timescale is still shorter than the disk lifetime except in the final disk evolution stage where the total disk mass decays below the planet mass. This suggests that most giant planets plunge into the central stars within the disk lifetime, and it contradicts the exoplanet observations that gas giants are piled up at r {approx}> 1 AU. We examine additional processes that may arise in protoplanetary disks: dead zones, photoevaporation of gas, and gas flow across a gap formed by a type II migrator. Although they make the type II migration timescale closer to the disk lifetime, we show that none of them can act as an effective barrier for rapid type II migration with the current knowledge of these processes. We point out that gas flow across a gap and the fraction of the flow accreted onto the planets are uncertain and they may have the potential to solve the problem. Much more detailed investigation for each process may be needed to explain the observed distribution of gas giants in extrasolar planetary systems.

  11. GIANT PLANETS ORBITING METAL-RICH STARS SHOW SIGNATURES OF PLANET-PLANET INTERACTIONS

    SciTech Connect

    Dawson, Rebekah I.; Murray-Clay, Ruth A.

    2013-04-20

    Gas giants orbiting interior to the ice line are thought to have been displaced from their formation locations by processes that remain debated. Here we uncover several new metallicity trends, which together may indicate that two competing mechanisms deliver close-in giant planets: gentle disk migration, operating in environments with a range of metallicities, and violent planet-planet gravitational interactions, primarily triggered in metal-rich systems in which multiple giant planets can form. First, we show with 99.1% confidence that giant planets with semimajor axes between 0.1 and 1 AU orbiting metal-poor stars ([Fe/H] < 0) are confined to lower eccentricities than those orbiting metal-rich stars. Second, we show with 93.3% confidence that eccentric proto-hot Jupiters undergoing tidal circularization primarily orbit metal-rich stars. Finally, we show that only metal-rich stars host a pile-up of hot Jupiters, helping account for the lack of such a pile-up in the overall Kepler sample. Migration caused by stellar perturbers (e.g., stellar Kozai) is unlikely to account for the trends. These trends further motivate follow-up theoretical work addressing which hot Jupiter migration theories can also produce the observed population of eccentric giant planets between 0.1 and 1 AU.

  12. Formation of terrestrial planets in eccentric and inclined giant-planet systems

    NASA Astrophysics Data System (ADS)

    Sotiriadis, Sotiris; Libert, Anne-Sophie; Raymond, Sean

    2016-10-01

    The orbits of extrasolar planets are more various than the circular and coplanar ones of the Solar system. We study the impact of inclined and eccentric massive giant planets on the terrestrial planet formation process. The physical and orbital parameters of the giant planets considered in this study arise from n-body simulations of three giant planets in the late stage of the gas disc, under the combined action of Type II migration and planet-planet scattering. At the dispersal of the gas disc, the two- and three-planet systems interact then with an inner disc of planetesimals and planetary embryos. We discuss the mass and orbital parameters of the terrestrial planets formed by our simulations, as well as their water content. We also investigate how the disc of planetesimals and planetary embryos modifies the eccentric and inclined orbits of the giant planets.

  13. Dynamics of Giant Planet Polar Vortices

    NASA Astrophysics Data System (ADS)

    Brueshaber, Shawn R.; Sayanagi, Kunio M.

    2016-10-01

    The polar atmospheres of the giant planets have come under increasing interest since a compact, warm-core, stable, cyclonic polar vortex was discovered at each of Saturn's poles. In addition, the south pole of Neptune appears to have a similar feature, and Uranus' north pole is exhibiting activity that could indicate the formation of a polar vortex. We investigate the formation and maintenance of these giant planet polar vortices by varying several key atmospheric dynamics parameters in a forced-dissipative, 1.5-layer shallow water model. Our simulations are run using the EPIC (Explicit Planetary Isentropic Coordinate) global circulation model, to which we have added a gamma-plane rectangular grid option appropriate for simulating polar atmospheric dynamics.In our numerical simulations, we vary the atmospheric deformation radius, planetary rotation rate, storm forcing intensity, and storm vorticity (cyclone-to-anticyclone) ratio to determine what combination of values favors the formation of a polar vortex. We find that forcing the atmosphere by injecting small-scale mass perturbations ("storms") to form either all cyclones, all anticyclones, or equal numbers of both, may all result in a cyclonic polar vortex. Additionally, we examine the role of eddy momentum convergence in the intensification and maintenance of a polar cyclone.Our simulation results are applicable to understanding all four of the solar system giant planets. In the future, we plan to expand our modeling effort with a more realistic 3D primitive equations model, also with a gamma-plane rectangular grid using EPIC. With our 3D primitive equations model, we will study how various vertical atmospheric stratification structures influence the formation and maintenance of a polar cyclone. While our shallow-water model only involves storms of a single layer, a 3D primitive equations model allows us to study how storms of finite vertical extent and at differing levels in the atmosphere may further favor

  14. IONIZATION OF EXTRASOLAR GIANT PLANET ATMOSPHERES

    SciTech Connect

    Koskinen, Tommi T.; Cho, James Y-K.; Achilleos, Nicholas; Aylward, Alan D.

    2010-10-10

    Many extrasolar planets orbit close in and are subject to intense ionizing radiation from their host stars. Therefore, we expect them to have strong, and extended, ionospheres. Ionospheres are important because they modulate escape in the upper atmosphere and can modify circulation, as well as leave their signatures, in the lower atmosphere. In this paper, we evaluate the vertical location Z{sub I} and extent D{sub I} of the EUV ionization peak layer. We find that Z{sub I{approx}}1-10 nbar-for a wide range of orbital distances (a = 0.047-1 AU) from the host star-and D{sub I}/H{sub p{approx}}>15, where H{sub p} is the pressure scale height. At Z{sub I}, the plasma frequency is {approx}80-450 MHz, depending on a. We also study global ion transport, and its dependence on a, using a three-dimensional thermosphere-ionosphere model. On tidally synchronized planets with weak intrinsic magnetic fields, our model shows only a small, but discernible, difference in electron density from the dayside to the nightside ({approx}9 x 10{sup 13} m{sup -3} to {approx}2 x 10{sup 12} m{sup -3}, respectively) at Z{sub I}. On asynchronous planets, the distribution is essentially uniform. These results have consequences for hydrodynamic modeling of the atmospheres of close-in extrasolar giant planets.

  15. Type II Migration and Giant Planet Survival

    NASA Technical Reports Server (NTRS)

    Ward, William R.

    2003-01-01

    Type II migration, in which a newly formed large planet opens a gap in its precursor circumstellar nebula and subsequently evolves with it, has been implicated as a delivery mechanism responsible for close stellar companions. Large scale migration is possible in a viscously spreading disk of surface density sigma (r,t) when most of it is sacrificed to the primary in order to promote a small portion of the disk to much higher angular momentum orbits. Embedded planets generally follow its evolution unless their own angular momentum is comparable to that of the disk. The fraction of the starting disk mass, M (sub d) = 2pi integral rsigma(r,0)dr, that is consumed by the star depends on the distance at which material escapes the disk's outer boundary. If the disk is allowed to expand indefinitely, virtually all of the disk will fall into the primary in order to send a vanishingly small portion to infinity. For such a case, it is difficult to explain the survival of any giant planets, including Jupiter and Saturn. Realistically, however, there are processes that could truncate a disk at a finite distance, r(sub d). Recent numerical modeling has illustrated that planets can survive in this case. We show here that much of these results can be understood by simple conservation arguments.

  16. EFFECTS OF DYNAMICAL EVOLUTION OF GIANT PLANETS ON SURVIVAL OF TERRESTRIAL PLANETS

    SciTech Connect

    Matsumura, Soko; Ida, Shigeru; Nagasawa, Makiko

    2013-04-20

    The orbital distributions of currently observed extrasolar giant planets allow marginally stable orbits for hypothetical, terrestrial planets. In this paper, we propose that many of these systems may not have additional planets on these ''stable'' orbits, since past dynamical instability among giant planets could have removed them. We numerically investigate the effects of early evolution of multiple giant planets on the orbital stability of the inner, sub-Neptune-like planets which are modeled as test particles, and determine their dynamically unstable region. Previous studies have shown that the majority of such test particles are ejected out of the system as a result of close encounters with giant planets. Here, we show that secular perturbations from giant planets can remove test particles at least down to 10 times smaller than their minimum pericenter distance. Our results indicate that, unless the dynamical instability among giant planets is either absent or quiet like planet-planet collisions, most test particles down to {approx}0.1 AU within the orbits of giant planets at a few AU may be gone. In fact, out of {approx}30% of survived test particles, about three quarters belong to the planet-planet collision cases. We find a good agreement between our numerical results and the secular theory, and present a semi-analytical formula which estimates the dynamically unstable region of the test particles just from the evolution of giant planets. Finally, our numerical results agree well with the observations, and also predict the existence of hot rocky planets in eccentric giant planet systems.

  17. The Obliquities of the Giant Planets

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.; Ward, Wm. R.

    2002-09-01

    Jupiter has by far the smallest obliquity ( ~ 3o) of the planets (not counting tidally de-spun Mercury and Venus) which may be reflective of its formation by hydrodynamic gas flow rather than stochastic impacts. Saturn's obliquity ( ~ 26o), however, seems to belie this simple formation picture. But since the spin angular momentum of any planet is much smaller than its orbital angular momentum, post-formation obliquity can be strongly modified by passing through secular spin-orbit resonances, i.e., when the spin axis precession rate of the planet matches one of the frequencies describing the precession of the orbit plane. Spin axis precession is due to the solar torque on both the oblate figure of the planet and any orbiting satellites. In the case of Jupiter, the torque on the Galilean satellites is the principal cause of its 4.5*105 year precession; Saturn's precession of 1.8*106 years is dominated by Titan. In the past, the planetary spin axis precession rates should have been much faster due to the massive circumplanetary disks from which the current satellites condensed. The regression of the orbital node of a planet is due to the gravitational perturbations of the other planets. Nodal regression is not uniform, but is instead a composite of the planetary system's normal modes. For Jupiter and Saturn, the principal frequency is the nu16, with a period of ~ 49,000 years; the amplitude of this term is I ~ 0o.36 for Jupiter and I ~ 0o.90 for Saturn. In spite of the small amplitudes, slow adiabatic passages through this resonance (due to circumplanetary disk dispersal) could increase planetary obliquities from near zero to ~ [tan1/3 I] ~ 10o. We will discuss scenarios in which giant planet obliquities are affected by this and other resonances, and will use Jupiter's low obliquity to constrain the mass and duration of a satellite precursor disk. DPH acknowledges support from NSF Career Grant AST 9733789 and WRW is grateful to the NASA OSS and PGG programs.

  18. Juno and Cassini Proximal: Giant Steps Towards Understanding Giant Planets

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.

    2014-12-01

    In 2016-17, Juno and Cassini Proximal will provide comparable large advances in our understanding of the interiors of Jupiter and Saturn. Both will provide high accuracy gravity and magnetic field data, while Juno will in addition determine the water abundance deep in the Jovian atmosphere, essential for understanding of giant planet formation and the density of the outer envelope (needed to construct interior models). Although Jupiter and Saturn are both gas giants, they differ in important ways (magnetic field, strength of zonal flows, enrichment in heavy elements, and probably the distribution of helium within). The opportunity to contrast and compare will be invaluable. Juno and Cassini are expected to determine the gravity field to about a part in 109 though with different spatial coverage and with less accurate determination near the poles. The determination of Jupiter's likely central concentration of heavy elements is particularly challenging because it is only a few percent at most of the total mass and yet important for understanding Jupiter's formation, which in turn likely determined the architecture of our solar system. This determination will be done from gravity, water determination and magnetic field and also aided by advances in our understanding of material properties. The corresponding determination for Saturn may prove easier (because the heavy element enrichment is a larger fraction of the mass) though complicated by lack of knowledge of water abundance and the need to identify a more precise value for the deep rotation of the planet (difficult for Saturn because of the lack of a measurable magnetic dipole tilt thus far). For both planets, the higher harmonics of gravity will likely be controlled by differential rotation (the zonal flows) and this will tell us their depth, an issue of major interest in the dynamics of these bodies. The magnetic field structure for Jupiter will be determined to higher accuracy than the Earth's core field (since

  19. Rotation Rates of the Giant Planets (Invited)

    NASA Astrophysics Data System (ADS)

    Schubert, G.; Helled, R.; Anderson, J. D.

    2009-12-01

    It has been generally believed that a rotation period could be assigned to each of the giant planets. Accepted values of these periods, till now, are 9h 55m 29s, 10h 39m 22s, 17h 14m 24s, and 16h 06m 36s for Jupiter, Saturn, Uranus, and Neptune, respectively. The rotation period of Jupiter is based on the periodic variations in the planet’s kilometric radiation and magnetic field, periodicities that have been unchanged since the Voyager flybys. The association of these periodicities with Jupiter’s internal rotation period is based on the idea that the radio and magnetic phenomena are tied to the planet’s magnetic field lines anchored deep within Jupiter. The periodic variations of the Saturnian Kilometric Radiation (SKR), unlike those of Jupiter, have not been rock solid, however; the periodicity has changed from 10h 39m 22s at the time of Voyager to 10h 45m 45s at the time of Cassini. Clearly, the SKR period does not represent the internal rotation period of Saturn, and it raises the possibility that the rotation periods of the other giant planets are uncertain. In fact, we must seriously reconsider whether the interiors of the giant planets are in solid body rotation with a single period. Even for Jupiter, the 9h 55m 29s rotation period might represent only the rotation of the region in which the magnetic field is generated. The dynamo region could extend from some unknown inner radius out to about 0.9 Jovian radius. The deeper Jovian interior could be rotating with a different period. A recent attempt to model the interior of Jupiter with new equation of state data concluded that the gravitational coefficients of Jupiter could not be fit unless Jupiter’s internal rotation rate was constant on cylinders parallel to the rotation axis (Militzer, B., W.B. Hubbard, J. Vorberger, I. Tamblyn, and S.A. Bonev, A massive core in Jupiter predicted from first-principles simulations, 2008, ApJ, 688, L45-L48 [doi: 10.1086/594364]). For Saturn, two studies of the

  20. Origin and evolution of the giant planets

    NASA Technical Reports Server (NTRS)

    Bodenheimer, P.

    1982-01-01

    A discussion is presented of two major giant planet origin hypotheses: (1) protoplanet formation in the solar nebula in the form of a gravitationally unstable, gaseous subcondensation, subsequently evolving as a chemically homogeneous object until a stage at which a solid core may form; and (2) solid core formation by accumulation of planetesimals, followed by the accretion of solar-composition gas onto the core until it becomes unstable to collapse. Under either of the scenarios, evolution is found to comprise an early, cool phase in hydrostatic equilibrium, a hydrodynamic collapse, and a final phase of hydrostatic contraction and cooling to the present state. Attention is given to the physical processes that are most important in the determination of evolutionary characteristics. A concluding note on the cases of Uranus and Neptune is also given.

  1. Interiors of giant planets inside and outside the solar system.

    PubMed

    Guillot, T

    1999-10-01

    An understanding of the structure and composition of the giant planets is rapidly evolving because of (i) high-pressure experiments with the ability to study metallic hydrogen and define the properties of its equation of state and (ii) spectroscopic and in situ measurements made by telescopes and satellites that allow an accurate determination of the chemical composition of the deep atmospheres of the giant planets. However, the total amount of heavy elements that Jupiter, Saturn, Uranus, and Neptune contain remains poorly constrained. The discovery of extrasolar giant planets with masses ranging from that of Saturn to a few times the mass of Jupiter opens up new possibilities for understanding planet composition and formation. Evolutionary models predict that gaseous extrasolar giant planets should have a variety of atmospheric temperatures and chemical compositions, but the radii are estimated to be close to that of Jupiter (between 0.9 and 1.7 Jupiter radii), provided that they contain mostly hydrogen and helium.

  2. The survival of gas giant planets on wide orbits

    NASA Astrophysics Data System (ADS)

    Stamatellos, Dimitris

    2015-12-01

    It is not known whether gas giant planets on wide orbits form the same way as Jupiter or by fragmentation of gravitationally unstable discs. It has been suggested that giant planets that form on wide orbits in gravitationally unstable discs quickly migrate towards the central star. We simulate the migration of such planets including the effects of gas accretion onto the planet and radiative feedback from the planet, both of which have been ignored in previous studies. We show that a giant planet, which has formed in the outer regions of a protostellar disc, initially migrates towards the central star while accreting gas from the disc. However, the planet eventually opens up a gap in the disc and the migration is essentially halted. At the same time, accretion-powered radiative feedback from the planet, significantly limits its mass growth, keeping it within the planetary mass regime (i.e. below the deuterium burning limit). Giant planets are therefore able to survive as planets (not higher-mass objects, i.e. brown dwarfs) on wide orbits, shaping the environment in which terrestrial planets that may harbour life form.

  3. Constraining Planetary Migration Mechanisms in Systems of Giant Planets

    NASA Astrophysics Data System (ADS)

    Dawson, Rebekah I.; Murray-Clay, Ruth A.; Johnson, John Asher

    2014-01-01

    It was once widely believed that planets formed peacefully in situ in their proto-planetary disks and subsequently remain in place. Instead, growing evidence suggests that many giant planets undergo dynamical rearrangement that results in planets migrating inward in the disk, far from their birthplaces. However, it remains debated whether this migration is caused by smooth planet-disk interactions or violent multi-body interactions. Both classes of model can produce Jupiter-mass planets orbiting within 0.1 AU of their host stars, also known as hot Jupiters. In the latter class of model, another planet or star in the system perturbs the Jupiter onto a highly eccentric orbit, which tidal dissipation subsequently shrinks and circularizes during close passages to the star. We assess the prevalence of smooth vs. violent migration through two studies. First, motivated by the predictions of Socrates et al. (2012), we search for super-eccentric hot Jupiter progenitors by using the ``photoeccentric effect'' to measure the eccentricities of Kepler giant planet candidates from their transit light curves. We find a significant lack of super- eccentric proto-hot Jupiters compared to the number expected, allowing us to place an upper limit on the fraction of hot Jupiters created by stellar binaries. Second, if both planet-disk and multi-body interactions commonly cause giant planet migration, physical properties of the proto-planetary environment may determine which is triggered. We identify three trends in which giant planets orbiting metal rich stars show signatures of planet-planet interactions: (1) gas giants orbiting within 1 AU of metal-rich stars have a range of eccentricities, whereas those orbiting metal- poor stars are restricted to lower eccentricities; (2) metal-rich stars host most eccentric proto-hot Jupiters undergoing tidal circularization; and (3) the pile-up of short-period giant planets, missing in the Kepler sample, is a feature of metal-rich stars and is

  4. The SEEDs of Planet Formation: Indirect Signatures of Giant Planets in Transitional Disks

    NASA Technical Reports Server (NTRS)

    Grady, Carol; Currie, T.

    2012-01-01

    We live in a planetary system with 2 gas giant planets, and as a resu lt of RV, transit, microlensing, and transit timing studies have ide ntified hundreds of giant planet candidates in the past 15 years. Su ch studies have preferentially concentrated on older, low activity So lar analogs, and thus tell us little about .when, where, and how gian t planets form in their disks, or how frequently they form in disks associated with intermediate-mass stars.

  5. Giant elves: Lightning-generated electromagnetic pulses in giant planets.

    NASA Astrophysics Data System (ADS)

    Luque Estepa, Alejandro; Dubrovin, Daria; José Gordillo-Vázquez, Francisco; Ebert, Ute; Parra-Rojas, Francisco Carlos; Yair, Yoav; Price, Colin

    2015-04-01

    We currently have direct optical observations of atmospheric electricity in the two giant gaseous planets of our Solar System [1-5] as well as radio signatures that are possibly generated by lightning from the two icy planets Uranus and Neptune [6,7]. On Earth, the electrical activity of the troposphere is associated with secondary electrical phenomena called Transient Luminous Events (TLEs) that occur in the mesosphere and lower ionosphere. This led some researchers to ask if similar processes may also exist in other planets, focusing first on the quasi-static coupling mechanism [8], which on Earth is responsible for halos and sprites and then including also the induction field, which is negligible in our planet but dominant in Saturn [9]. However, one can show that, according to the best available estimation for lightning parameters, in giant planets such as Saturn and Jupiter the effect of the electromagnetic pulse (EMP) dominates the effect that a lightning discharge has on the lower ionosphere above it. Using a Finite-Differences, Time-Domain (FDTD) solver for the EMP we found [10] that electrically active storms may create a localized but long-lasting layer of enhanced ionization of up to 103 cm-3 free electrons below the ionosphere, thus extending the ionosphere downward. We also estimate that the electromagnetic pulse transports 107 J to 1010 J toward the ionosphere. There emissions of light of up to 108 J would create a transient luminous event analogous to a terrestrial elve. Although these emissions are about 10 times fainter than the emissions coming from the lightning itself, it may be possible to target them for detection by filtering the appropiate wavelengths. [1] Cook, A. F., II, T. C. Duxbury, and G. E. Hunt (1979), First results on Jovian lightning, Nature, 280, 794, doi:10.1038/280794a0. [2] Little, B., C. D. Anger, A. P. Ingersoll, A. R. Vasavada, D. A. Senske, H. H. Breneman, W. J. Borucki, and The Galileo SSI Team (1999), Galileo images of

  6. Theories of the origin and evolution of the giant planets

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Bodenheimer, P.

    1989-01-01

    Following the accretion of solids and gases in the solar nebula, the giant planets contracted to their present sizes over the age of the solar system. It is presently hypothesized that this contraction was rapid, but not hydrodynamic; at a later stage, a nebular disk out of which the regular satellites formed may have been spun out of the outer envelope of the contracting giant planets due to a combination of total angular momentum conservation and the outward transfer of specific angular momentum in the envelope. If these hypotheses are true, the composition of the irregular satellites directly reflects the composition of planetesimals from which the giant planets formed, while the composition of the regular satellites is indicative of the composition of the less volatile components of the outer envelopes of the giant planets.

  7. Giant Planet Observations with the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Norwood, James; Moses, Julianne; Fletcher, Leigh N.; Orton, Glenn; Irwin, Patrick G. J.; Atreya, Sushil; Rages, Kathy; Cavalié, Thibault; Sánchez-Lavega, Agustin; Hueso, Ricardo; Chanover, Nancy

    2016-01-01

    This white paper examines the benefit of the upcoming James Webb Space Telescope (JWST) for studies of the Solar System's four giant planets: Jupiter, Saturn, Uranus, and Neptune. JWST's superior sensitivity, combined with high spatial and spectral resolution, will enable near- and mid-infrared imaging and spectroscopy of these objects with unprecedented quality. In this paper, we discuss some of the myriad scientific investigations possible with JWST regarding the giant planets. This discussion is preceded by the specifics of JWST instrumentation most relevant to giant-planet observations. We conclude with identification of desired pre-launch testing and operational aspects of JWST that would greatly benefit future studies of the giant planets.

  8. The dependence of giant planet migration on disk and planet properties

    NASA Astrophysics Data System (ADS)

    Moorhead, Althea; Ford, E. B.

    2010-05-01

    Given the severe challenges in forming giant planets so close to their host star, disk-induced migration is often invoked to explain their small semi-major axes. Migration theory is usually divided into two limiting cases: Type I migration, in which the planet remains embedded in the disk, and Type II migration, in which the planet is sufficiently massive that it clears a gap in the disk in the vicinity of its orbit and follows the viscous evolution of the disk. However, recent hydrodynamic simulations of giant planets in circumstellar disks do not seem to follow this prescription; giant planet migration rates show a dependence on planet mass that is inconsistent with migrration on a constant, viscous timescale (Edgar 2008). We use FARGO to extend the work of Edgar (2008) and Bate (2003) to higher viscosities and larger planet masses and present the results in the context of distinguishing between the standard description of giant planet migration and that of Edgar (2007). Additionally, we present simulations of planets on eccentric orbits and describe how eccentricity modifies giant planet migration.

  9. Capture of terrestrial-sized moons by gas giant planets.

    PubMed

    Williams, Darren M

    2013-04-01

    Terrestrial moons with masses >0.1 M (symbol in text) possibly exist around extrasolar giant planets, and here we consider the energetics of how they might form. Binary-exchange capture can occur if a binary-terrestrial object (BTO) is tidally disrupted during a close encounter with a giant planet and one of the binary members is ejected while the other remains as a moon. Tidal disruption occurs readily in the deep gravity wells of giant planets; however, the large encounter velocities in the wells make binary exchange more difficult than for planets of lesser mass. In addition, successful capture favors massive binaries with large rotational velocities and small component mass ratios. Also, since the interaction tends to leave the captured moons on highly elliptical orbits, permanent capture is only possible around planets with sizable Hill spheres that are well separated from their host stars. PMID:23537110

  10. Directly Imaged Giant Planets: What Do We Hope to Learn?

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2015-01-01

    As we move into an era when GPI and SPHERE are (hopefully) discovering and characterizing new young giant planets, it is worthwhile to step back and review our science goals for young giant planets. Of course for individual planets we ideally would hope to measure mass, radius, atmospheric composition, temperature, and cloud properties, but how do these characteristics fit into our broader understanding of planetary system origin and evolution theories? In my presentation I will review both the specifics of what we hope to learn from newly discovered young worlds as well as how these characteristics inform our broader understanding of giant planets and planetary systems. Finally I will consider the limitations realistic datasets will place on our ability to understand newly discovered planets, illustrating with data from any new such worlds that are available by the conference date.

  11. Capture of terrestrial-sized moons by gas giant planets.

    PubMed

    Williams, Darren M

    2013-04-01

    Terrestrial moons with masses >0.1 M (symbol in text) possibly exist around extrasolar giant planets, and here we consider the energetics of how they might form. Binary-exchange capture can occur if a binary-terrestrial object (BTO) is tidally disrupted during a close encounter with a giant planet and one of the binary members is ejected while the other remains as a moon. Tidal disruption occurs readily in the deep gravity wells of giant planets; however, the large encounter velocities in the wells make binary exchange more difficult than for planets of lesser mass. In addition, successful capture favors massive binaries with large rotational velocities and small component mass ratios. Also, since the interaction tends to leave the captured moons on highly elliptical orbits, permanent capture is only possible around planets with sizable Hill spheres that are well separated from their host stars.

  12. Kepler-108: A Mutually Inclined Giant Planet System

    NASA Astrophysics Data System (ADS)

    Mills, Sean M.; Fabrycky, Daniel

    2016-06-01

    The vast majority of well studied giant-planet systems, including the Solar System, are nearly coplanar which implies dissipation within a primordial gas disk. However, intrinsic instability may lead to planet-planet scattering, which often produces non-coplanar, eccentric orbits. Planet scattering theories have been developed to explain observed high eccentricity systems and possibly hot Jupiters; thus far their predictions for mutual inclination (I) have barely been tested. Here we characterize a highly mutually-inclined (I ~ 15-60 degrees), moderately eccentric (e > 0.1) giant planet system: Kepler-108. This system consists of two Saturn mass planets with periods of ~49 and ~190 days around a star with a wide (~300 AU) binary companion in an orbital configuration inconsistent with a purely disk migration origin.

  13. THE HEAVY-ELEMENT MASSES OF EXTRASOLAR GIANT PLANETS, REVEALED

    SciTech Connect

    Miller, Neil; Fortney, Jonathan J.

    2011-08-01

    We investigate a population of transiting planets that receive relatively modest stellar insolation, indicating equilibrium temperatures <1000 K, and for which the heating mechanism that inflates hot Jupiters does not appear to be significantly active. We use structural evolution models to infer the amount of heavy elements within each of these planets. There is a correlation between the stellar metallicity and the mass of heavy elements in its transiting planet(s). It appears that all giant planets possess a minimum of {approx}10-15 Earth masses of heavy elements, with planets around metal-rich stars having larger heavy-element masses. There is also an inverse relationship between the mass of the planet and the metal enrichment (Z{sub pl}/Z{sub star}), which appears to have little dependency on the metallicity of the star. Saturn- and Jupiter-like enrichments above solar composition are a hallmark of all the gas giants in the sample, even planets of several Jupiter masses. These relationships provide an important constraint on planet formation and suggest large amounts of heavy elements within planetary H/He envelopes. We suggest that the observed correlation can soon also be applied to inflated planets, such that the interior heavy-element abundance of these planets could be estimated, yielding better constraints on their interior energy sources. We point to future directions for planetary population synthesis models and suggest future correlations. This appears to be the first evidence that extrasolar giant planets, as a class, are enhanced in heavy elements.

  14. The Mass–Metallicity Relation for Giant Planets

    NASA Astrophysics Data System (ADS)

    Thorngren, Daniel P.; Fortney, Jonathan J.; Murray-Clay, Ruth A.; Lopez, Eric D.

    2016-11-01

    Exoplanet discoveries of recent years have provided a great deal of new data for studying the bulk compositions of giant planets. Here we identify 47 transiting giant planets (20 M ⊕ < M < 20 M J) whose stellar insolations are low enough (F * < 2 × 108 erg s‑1 cm‑2, or roughly T eff < 1000) that they are not affected by the hot-Jupiter radius inflation mechanism(s). We compute a set of new thermal and structural evolution models and use these models in comparison with properties of the 47 transiting planets (mass, radius, age) to determine their heavy element masses. A clear correlation emerges between the planetary heavy element mass M z and the total planet mass, approximately of the form {M}z\\propto \\sqrt{M}. This finding is consistent with the core-accretion model of planet formation. We also study how stellar metallicity [Fe/H] affects planetary metal-enrichment and find a weaker correlation than has previously been reported from studies with smaller sample sizes. We confirm a strong relationship between the planetary metal-enrichment relative to the parent star Z planet/Z star and the planetary mass, but see no relation in Z planet/Z star with planet orbital properties or stellar mass. The large heavy element masses of many planets (>50 M ⊕) suggest significant amounts of heavy elements in H/He envelopes, rather than cores, such that metal-enriched giant planet atmospheres should be the rule. We also discuss a model of core-accretion planet formation in a one-dimensional disk and show that it agrees well with our derived relation between mass and Z planet/Z star.

  15. POSSIBLE SIGNATURES OF MAGNETOSPHERIC ACCRETION ONTO YOUNG GIANT PLANETS

    SciTech Connect

    Lovelace, R. V. E.; Covey, K. R.; Lloyd, J. P. E-mail: kcovey@astro.cornell.edu

    2011-02-15

    Magnetospheric accretion is an important process for a wide range of astrophysical systems and may play a role in the formation of gas giant planets. Extending the formalism describing stellar magnetospheric accretion into the planetary regime, we demonstrate that magnetospheric processes may govern accretion onto young gas giants in the isolation phase of their development. Planets in the isolation phase have cleared out large gaps in their surrounding circumstellar disks and settled into a quasi-static equilibrium with radii only modestly larger than their final sizes (i.e., r {approx} 1.4r{sub final}). Magnetospheric accretion is less likely to play a role in a young gas giant's main accretion phase, when the planet's envelope is predicted to be much larger than the planet's Alfven radius. For a fiducial 1 M{sub J} gas giant planet with a remnant isolation phase accretion rate of M-dot{sub sun}= 10{sup -10} M{sub sun} yr{sup -1} = 10{sup -7} M{sub J} yr{sup -1}, the disk accretion will be truncated at {approx}2.7r{sub J} (with r{sub J} is Jupiter's radius) and drive the planet to rotate with a period of {approx}7 hr. Thermal emission from planetary magnetospheric accretion will be difficult to observe; the most promising observational signatures may be non-thermal, such as gyrosynchrotron radiation that is clearly modulated at a period much shorter than the rotation period of the host star.

  16. Long-term evolution of planetary systems with a terrestrial planet and a giant planet

    NASA Astrophysics Data System (ADS)

    Georgakarakos, Nikolaos; Dobbs-Dixon, Ian; Way, Michael J.

    2016-09-01

    We study the long-term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet. In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine both possible configurations: the giant planet orbit being either outside or inside the orbit of the smaller planet. The perturbing potential is expanded to high orders, and an analytical solution of the terrestrial planetary orbit is derived. The analytical estimates are then compared against results from the numerical integration of the full equations of motion, and we find that the analytical solution works reasonably well. An interesting finding is that the new analytical estimates improve greatly the predictions for the time-scales of the orbital evolution of the terrestrial planet compared to an octupole order expansion. Finally, we briefly discuss possible applications of the analytical estimates in astrophysical problems.

  17. Long Term Evolution of Planetary Systems with a Terrestrial Planet and a Giant Planet

    NASA Technical Reports Server (NTRS)

    Georgakarakos, Nikolaos; Dobbs-Dixon, Ian; Way, Michael J.

    2016-01-01

    We study the long term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet. In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine both possible configurations: the giant planet orbit being either outside or inside the orbit of the smaller planet. The perturbing potential is expanded to high orders and an analytical solution of the terrestrial planetary orbit is derived. The analytical estimates are then compared against results from the numerical integration of the full equations of motion and we find that the analytical solution works reasonably well. An interesting finding is that the new analytical estimates improve greatly the predictions for the timescales of the orbital evolution of the terrestrial planet compared to an octupole order expansion. Finally, we briefly discuss possible applications of the analytical estimates in astrophysical problems.

  18. Interiors of giant planets inside and outside the solar system.

    PubMed

    Guillot, T

    1999-10-01

    An understanding of the structure and composition of the giant planets is rapidly evolving because of (i) high-pressure experiments with the ability to study metallic hydrogen and define the properties of its equation of state and (ii) spectroscopic and in situ measurements made by telescopes and satellites that allow an accurate determination of the chemical composition of the deep atmospheres of the giant planets. However, the total amount of heavy elements that Jupiter, Saturn, Uranus, and Neptune contain remains poorly constrained. The discovery of extrasolar giant planets with masses ranging from that of Saturn to a few times the mass of Jupiter opens up new possibilities for understanding planet composition and formation. Evolutionary models predict that gaseous extrasolar giant planets should have a variety of atmospheric temperatures and chemical compositions, but the radii are estimated to be close to that of Jupiter (between 0.9 and 1.7 Jupiter radii), provided that they contain mostly hydrogen and helium. PMID:10506563

  19. Hydrodynamic simulations of the interaction between giant stars and planets

    NASA Astrophysics Data System (ADS)

    Staff, Jan E.; De Marco, Orsola; Wood, Peter; Galaviz, Pablo; Passy, Jean-Claude

    2016-05-01

    We present the results of hydrodynamic simulations of the interaction between a 10 Jupiter mass planet and a red or asymptotic giant branch stars, both with a zero-age main sequence mass of 3.5 M⊙. Dynamic in-spiral time-scales are of the order of few years and a few decades for the red and asymptotic giant branch stars, respectively. The planets will eventually be destroyed at a separation from the core of the giants smaller than the resolution of our simulations, either through evaporation or tidal disruption. As the planets in-spiral, the giant stars' envelopes are somewhat puffed up. Based on relatively long time-scales and even considering the fact that further in-spiral should take place before the planets are destroyed, we predict that the merger would be difficult to observe, with only a relatively small, slow brightening. Very little mass is unbound in the process. These conclusions may change if the planet's orbit enhances the star's main pulsation modes. Based on the angular momentum transfer, we also suspect that this star-planet interaction may be unable to lead to large-scale outflows via the rotation-mediated dynamo effect of Nordhaus and Blackman. Detectable pollution from the destroyed planets would only result for the lightest, lowest metallicity stars. We furthermore find that in both simulations the planets move through the outer stellar envelopes at Mach-3 to Mach-5, reaching Mach-1 towards the end of the simulations. The gravitational drag force decreases and the in-spiral slows down at the sonic transition, as predicted analytically.

  20. Exploring How Giant Planet Formation Affected the Asteroid Belt

    NASA Astrophysics Data System (ADS)

    Kretke, Katherine A.; Levison, Harold F.; Bottke, William

    2016-10-01

    The asteroid belt is observed to be a mixture of objects with different compositions, with volatile-poor asteroids (mostly S-complex) dominant in the inner asteroid belt while volatile-rich (mostly C-complex) asteroids dominate the outer asteroid belt. While this general compositional stratification was originally thought to be an indicator of the primordial temperature gradient in the protoplanetary disk, the very distinct properties of these populations suggest that they must represent two completely decoupled reservoirs, not a simple gradient (e.g., Warren 2011). It is possible to create this general stratification (as well as the observed mixing) as the implantation of outer Solar System material into the asteroid belt by the early migration of the giant planets (e.g. the Grand Tack, Walsh et al. 2011). However, this presupposes that the inner and outer Solar System materials were still sorted in their primordial locations prior to any migration of the planets. The lack of a fully dynamically self-consistent model of giant planet core formation has prevented the study of how the core formation process itself may result in dynamical mixing in the early Solar System's history. Recently, pebble accretion, the process by which planetesimals can grow to giant planet cores via the accretion of small, rapidly drifting sub-meter-sized bodies known as ``pebbles,'' (Lambrechts & Johansen 2012, Levison, Kretke & Duncan 2015) finally offers such a model. Here we show how the process of giant planet formation will impact the surrounding planetesimal population, possibly resulting in the observed compositional mixture of the asteroid belt, without requiring a dramatic migration of the giant planets. For example, preliminary runs suggest planetesimals from the Jupiter-formation zone can be implanted in the outer main belt via interactions with scattered Jupiter-zone protoplanets. This could potentially provide an alternative non-Grand Tack solution to the origin of many C

  1. Early Giant Planet Candidates from the SDSS-III MARVELS Planet Survey

    NASA Astrophysics Data System (ADS)

    Thomas, Neil; Ge, J.; Li, R.; Sithajan, S.; Chen, Y.; Shi, J.; Ma, B.; Liu, J.

    2014-01-01

    We report the first discoveries of giant planet candidates from the SDSS-III MARVELS survey. These candidates are found using the new MARVELS data pipeline developed at UF from scratch over the past two years. Unlike the old data pipeline, this pipeline carefully corrects most of the instrument effects (such as trace, slant, distortion, drifts and dispersion) and observation condition effects (such as illumination profile). The result is long-term RV precisions that approach the photon limits in many cases and has yielded four giant planet candidates of ~1-6 Jupiter mass from only the initial fraction of data processed with the new techniques. More survey data is being processed which will likely lead to discoveries of additional giant planet candidates that will be verified and characterized with follow-up observations by the MARVELS team. The MARVELS survey has produced the largest homogeneous RV measurements of 3300 V=7.6-12 FGK stars with well defined cadence 27 RV measurements over 2 years). The MARVELS RV data and other follow-up data (photometry, high contrast imaging, high resolution spectroscopy and RV measurements) will explore the diversity of giant planet companion formation and evolution around stars with a broad range in metallicity ([Fe/H -1.5-0.5), mass ( 0.6-2.5M(sun)), and environment (thin disk and thick disk), and will help to address the key scientific questions identified for the MARVELS survey including, but not limited to: Do metal poor stars obey the same trends for planet occurrence as metal rich stars? What is the distribution of giant planets around intermediate-mass stars and binaries? Is the “planet desert” within 0.6 AU in the planet orbital distribution of intermediate-mass stars real?

  2. Mechanisms of jet formation on the giant planets

    NASA Astrophysics Data System (ADS)

    Liu, J.; Schneider, T.

    2009-12-01

    The giant planet atmospheres exhibit alternating prograde (eastward) and retrograde (westward) jets of different speeds and widths, with an equatorial jet that is prograde on Jupiter and Saturn and retrograde on Uranus and Neptune (Porco et al. 2003, Sanchez-Lavega et al. 2003, Sanchez-Lavega et al. 2007, Hammel et al. 2001, Sromovsky et al. 2001). The jets are variously thought to be driven by differential radiative heating of the upper atmosphere or by intrinsic heat fluxes emanating from the deep interior (Williams 2003, Busse 1976, Heimpel et al. 2005, Aurnou et al. 2007). But existing models cannot account for the different flow configurations on the giant planets in an energetically consistent manner (Heimpel and Aurnou 2007, Aurnou et al. 2007). Here we use simulations with a three-dimensional general circulation model to show that the different flow configurations can be reproduced by mechanisms universal across the giant planets if differences in their radiative heating and intrinsic heat fluxes are taken into account. Whether the equatorial jet is prograde or retrograde depends on whether the deep intrinsic heat fluxes are strong enough that convection penetrates into the upper atmosphere and excites strong equatorial Rossby waves there. The different speeds and widths of the off-equatorial jets depend, among other factors, on the differential radiative heating of the atmosphere and the altitude of the jets. The simulations make predictions about as-yet unobserved aspects of the flow and temperature structures of the giant planets.

  3. Miscibility Calculations for Water and Hydrogen in Giant Planets

    NASA Astrophysics Data System (ADS)

    Soubiran, François; Militzer, Burkhard

    2015-06-01

    We present results from ab initio simulations of liquid water–hydrogen mixtures in the range from 2 to 70 GPa and from 1000 to 6000 K, covering conditions in the interiors of ice giant planets and parts of the outer envelope of gas giant planets. In addition to computing the pressure and the internal energy, we derive the Gibbs free energy by performing a thermodynamic integration. For all conditions under consideration, our simulations predict hydrogen and water to mix in all proportions. The thermodynamic behavior of the mixture can be well described with an ideal mixing approximation. We suggest that a substantial fraction of water and hydrogen in giant planets may occur in homogeneously mixed form rather than in separate layers. The extent of mixing depends on the planet’s interior dynamics and its conditions of formation, in particular on how much hydrogen was present when icy planetesimals were delivered. Based on our results, we do not predict water–hydrogen mixtures to phase separate during any stage of the evolution of giant planets. We also show that the hydrogen content of an exoplanet is much higher if the mixed interior is assumed.

  4. MISCIBILITY CALCULATIONS FOR WATER AND HYDROGEN IN GIANT PLANETS

    SciTech Connect

    Soubiran, François; Militzer, Burkhard

    2015-06-20

    We present results from ab initio simulations of liquid water–hydrogen mixtures in the range from 2 to 70 GPa and from 1000 to 6000 K, covering conditions in the interiors of ice giant planets and parts of the outer envelope of gas giant planets. In addition to computing the pressure and the internal energy, we derive the Gibbs free energy by performing a thermodynamic integration. For all conditions under consideration, our simulations predict hydrogen and water to mix in all proportions. The thermodynamic behavior of the mixture can be well described with an ideal mixing approximation. We suggest that a substantial fraction of water and hydrogen in giant planets may occur in homogeneously mixed form rather than in separate layers. The extent of mixing depends on the planet’s interior dynamics and its conditions of formation, in particular on how much hydrogen was present when icy planetesimals were delivered. Based on our results, we do not predict water–hydrogen mixtures to phase separate during any stage of the evolution of giant planets. We also show that the hydrogen content of an exoplanet is much higher if the mixed interior is assumed.

  5. Could Jupiter or Saturn Have Ejected a Fifth Giant Planet?

    NASA Astrophysics Data System (ADS)

    Cloutier, Ryan; Tamayo, Daniel; Valencia, Diana

    2015-11-01

    Models of the dynamical evolution of the early solar system that follow the dispersal of the gaseous protoplanetary disk have been widely successful in reconstructing the current orbital configuration of the giant planets. Statistically, some of the most successful dynamical evolution simulations have initially included a hypothetical fifth giant planet, of ice giant (IG) mass, which gets ejected by a gas giant during the early solar system’s proposed instability phase. We investigate the likelihood of an IG ejection (IGE) event by either Jupiter or Saturn through constraints imposed by the current orbits of their wide-separation regular satellites Callisto and Iapetus, respectively. We show that planetary encounters that are sufficient to eject an IG often provide excessive perturbations to the orbits of Callisto and Iapetus, making it difficult to reconcile a planet ejection event with the current orbit of either satellite. Quantitatively, we compute the likelihood of reconciling a regular Jovian satellite orbit with the current orbit of Callisto following an IGE by Jupiter of ∼42%, and conclude that such a large likelihood supports the hypothesis of a fifth giant planet’s existence. A similar calculation for Iapetus reveals that it is much more difficult for Saturn to have ejected an IG and reconciled a Kronian satellite orbit with that of Iapetus (likelihood ∼1%), although uncertainties regarding the formation of Iapetus, with its unusual orbit, complicates the interpretation of this result.

  6. Giant Planet Accretion And Migration: Surviving The Type I Regime

    NASA Astrophysics Data System (ADS)

    Thommes, Edward; Murray, N.

    2006-06-01

    In the core accretion model of gas giant planet formation, a large solid core about 10X the Earth's mass forms first, then accumulates its massive envelope ( 100 or more Earth masses) of gas. However, inward planet migration due to gravitational interaction with the proto-stellar gas disk poses a big hazard in this model. Core-sized bodies undergo rapid "type I" migration; for typical parameters their migration timescale is much shorter than their accretion timescale. How, then, do growing cores avoid spiraling into the central star before they ever get the chance to become gas giants? I will present a simple model of core formation in a gas disk which is viscously evolving. It turns out that as the disk accretes onto the star, a window of opportunity for successful core growth may open. I will discuss what implications this model has for the link between disk properties and the likelihood of forming gas giants.

  7. Giant Planets on Resonant Orbits: The Effect of Mass Growth

    NASA Astrophysics Data System (ADS)

    Marzari, Francesco; D'Angelo, Gennaro

    Two giant planets that undergo convergent migration, driven by tidal interactions with their gaseous disk, may become locked into a mean motion resonance (MMR). For planet masses similar to those of Jupiter (the internal planet) and Saturn and for typical post-formation (i.e., after planets have formed) disk conditions, capture occurs in the 2:1 MMR (D'Angelo and Marzari 2012). Capture in the 3:2 MMR may occur if the post-formation gas density around the planet locations is large enough (e.g., > ~2000 g/cm2 at ~1AU). This scenario, however, neglects the effects of ongoing gas accretion on the planets, which may be significant especially at large disk gas densities. In fact, recent work (Gressel et al. 2013; Keith and Wardle 2014), suggests that even if turbulence in the proximity of the planets is caused by MRI, gas accretion may still be vigorous. In particular, the MHD calculations of Gressel et al. (2013) resulted in accretion rates compatible to those derived from hydrodynamical calculations (D'Angelo et al. 2003; Bate et al. 2003). In order to address this issue, we perform hydrodynamical models of the evolution of a pair of planets that interact with each other and with the disk. The planets are initially locked in the 2:1 or 3:2 MMR. Gas accretion depends on the local disk mass. The large gas densities required for capture in the 3:2 MMR rapidly change the planet masses and mass ratio. Ensuing planet-planet interactions affect orbital eccentricities, leading to scattering and ejection episodes. The conditions required by 2:1 MMR locking can also produce a significant mass growth, if the local disk is sufficiently massive. For planets orbiting in the 1 AU region, however, the resonant configuration appears stable up to several Jupiter's masses.

  8. THE GEMINI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF GIANT PLANETS AROUND DEBRIS DISK STARS

    SciTech Connect

    Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Ftaclas, Christ; Chun, Mark; Biller, Beth A.; Hayward, Thomas L.; Thatte, Niranjan; Tecza, Matthias; Shkolnik, Evgenya L.; Kuchner, Marc; Reid, I. Neill; De Gouveia Dal Pino, Elisabete M.; Gregorio-Hetem, Jane; Boss, Alan; Lin, Douglas N. C.; and others

    2013-08-20

    We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.''5 and 14.1 mag at 1'' separation. Follow-up observations of the 66 candidates with projected separation <500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known {beta} Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a {>=}5 M{sub Jup} planet beyond 80 AU, and <21% of debris disk stars have a {>=}3 M{sub Jup} planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly imaged planets as d {sup 2} N/dMda{proportional_to}m {sup {alpha}} a {sup {beta}}, where m is planet mass and a is orbital semi-major axis (with a maximum value of a{sub max}). We find that {beta} < -0.8 and/or {alpha} > 1.7. Likewise, we find that {beta} < -0.8 and/or a{sub max} < 200 AU. For the case where the planet frequency rises sharply with mass ({alpha} > 1.7), this occurs because all the planets detected to date have masses above 5 M{sub Jup}, but planets of lower mass could easily have been detected by our search. If we ignore the {beta} Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a {>=}3 M{sub Jup} planet beyond 10 AU, and {beta} < -0.8 and/or {alpha} < -1.5. Likewise, {beta} < -0.8 and/or a{sub max} < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet

  9. Outward Migration of Giant Planets in Orbital Resonance

    NASA Astrophysics Data System (ADS)

    D'Angelo, G.; Marzari, F.

    2013-05-01

    A pair of giant planets interacting with a gaseous disk may be subject to convergent orbital migration and become locked into a mean motion resonance. If the orbits are close enough, the tidal gaps produced by the planets in the disk may overlap. This represents a necessary condition to activate the outward migration of the pair. However, a number of other conditions must also be realized in order for this mechanism to operate. We have studied how disk properties, such as turbulence viscosity, temperature, surface density gradient, mass, and age, may affect the outcome of the outward migration process. We have also investigated the implications on this mechanism of the planets' gas accretion. If the pair resembles Jupiter and Saturn, the 3:2 orbital resonance may drive them outward until they reach stalling radii for migration, which are within ~10 AU of the star for disks representative of the early proto-solar nebula. However, planet post-formation conditions in the disk indicate that such planets become typically locked in the 1:2 orbital resonance, which does not lead to outward migration. Planet growth via gas accretion tends to alter the planets' mass-ratio and/or the disk accretion rate toward the star, reducing or inhibiting outward migration. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

  10. Giant Planet Accretion and Migration: Surviving the Type I Regime

    NASA Astrophysics Data System (ADS)

    Thommes, Edward W.; Murray, Norman

    2006-06-01

    In the standard model of gas giant planet formation, a large solid core (~10 times the Earth's mass) forms first, then accretes its massive envelope (100 or more Earth masses) of gas. However, inward planet migration due to gravitational interaction with the protostellar gas disk poses a difficulty in this model. Core-sized bodies undergo rapid ``type I'' migration; for typical parameters their migration timescale is much shorter than their accretion timescale. How, then, do growing cores avoid spiraling into the central star before they ever get the chance to become gas giants? Here, we present a simple model of core formation in a gas disk that is viscously evolving. As the disk dissipates, accretion and migration timescales eventually become comparable. If this happens while there is still enough gas left in the disk to supply a Jovian atmosphere, then a window of opportunity for gas giant formation opens. We examine under what circumstances this happens, and thus, what predictions our model makes about the link between protostellar disk properties and the likelihood of forming giant planets.

  11. Habitable moons around extrasolar giant planets

    NASA Technical Reports Server (NTRS)

    Williams, D. M.; Kasting, J. F.; Wade, R. A.

    1997-01-01

    Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere.

  12. Habitable moons around extrasolar giant planets.

    PubMed

    Williams, D M; Kasting, J F; Wade, R A

    1997-01-16

    Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere.

  13. Habitable moons around extrasolar giant planets.

    PubMed

    Williams, D M; Kasting, J F; Wade, R A

    1997-01-16

    Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere. PMID:9000072

  14. Gas Flow Near a Young Gas Giant Planet

    NASA Astrophysics Data System (ADS)

    Lubow, S.

    2004-12-01

    The mass acquired by a gas giant planet has long been believed to result from accretion of material within the surrounding gaseous disk (nebula). Bate, D'Angelo, and I have analyzed the properties and consequences of this flow by means of three-dimensional hydrodynamical simulations. Most of the accretion occurs after the planet has partially cleared a gap in the surrounding disk. The flow through the gap leads to accretion within the planet's Hill sphere. In that region, a circumplanetary disk forms which can serve as a site for satellite formation. The flow onto this disk is fully three-dimensional and involves shock production. The nebula exerts a torque on the planet that causes it to migrate radially. We have recently examined the torques produced by the material within the gap and within the Hill sphere.

  15. Star-planet interactions. II. Is planet engulfment the origin of fast rotating red giants?

    NASA Astrophysics Data System (ADS)

    Privitera, Giovanni; Meynet, Georges; Eggenberger, Patrick; Vidotto, Aline A.; Villaver, Eva; Bianda, Michele

    2016-10-01

    Context. Fast rotating red giants in the upper part of the red giant branch have surface velocities that cannot be explained by single star evolution. Aims: We check whether tides between a star and a planet followed by planet engulfment can indeed accelerate the surface rotation of red giants for a sufficiently long time to produce these fast rotating red giants. Methods: We studied how the surface rotation velocity at the stellar surface evolves using rotating stellar models, accounting for the redistribution of the angular momentum inside the star by different transport mechanisms, the exchanges of angular momentum between the planet orbit and the star before the engulfment, and for the deposition of angular momentum inside the star at the engulfment. We considered different situations with masses of stars in the range between 1.5 and 2.5 M⊙, masses of the planets between 1 and 15 MJ (Jupiter mass), and initial semimajor axis between 0.5 and 1.5 au. The metallicity Z for our stellar models is 0.02. Results: We show that the surface velocities reached at the end of the orbital decay due to tidal forces and planet engulfment can be similar to values observed for fast rotating red giants. This surface velocity then decreases when the star evolves along the red giant branch but at a sufficiently slow pace to allowing stars to be detected with such a high velocity. More quantitatively, star-planet interaction can produce a rapid acceleration of the surface of the star, above values equal to 8 km s-1, for periods lasting up to more than 30% the red giant branch phase. As found already by previous works, the changes of the surface carbon isotopic ratios produced by the dilution of the planetary material into the convective envelope is modest. The increase of the lithium abundance due to this effect might be much more important, however lithium may be affected by many different, still uncertain, processes. Thus any lithium measurement can hardly be taken as a support

  16. On the Composition of Young, Directly Imaged Giant Planets

    NASA Astrophysics Data System (ADS)

    Moses, J. I.; Marley, M. S.; Zahnle, K.; Line, M. R.; Fortney, J. J.; Barman, T. S.; Visscher, C.; Lewis, N. K.; Wolff, M. J.

    2016-10-01

    The past decade has seen significant progress on the direct detection and characterization of young, self-luminous giant planets at wide orbital separations from their host stars. Some of these planets show evidence for disequilibrium processes like transport-induced quenching in their atmospheres; photochemistry may also be important, despite the large orbital distances. These disequilibrium chemical processes can alter the expected composition, spectral behavior, thermal structure, and cooling history of the planets, and can potentially confuse determinations of bulk elemental ratios, which provide important insights into planet-formation mechanisms. Using a thermo/photochemical kinetics and transport model, we investigate the extent to which disequilibrium chemistry affects the composition and spectra of directly imaged giant exoplanets. Results for specific “young Jupiters” such as HR 8799 b and 51 Eri b are presented, as are general trends as a function of planetary effective temperature, surface gravity, incident ultraviolet flux, and strength of deep atmospheric convection. We find that quenching is very important on young Jupiters, leading to CO/CH4 and N2/NH3 ratios much greater than, and H2O mixing ratios a factor of a few less than, chemical-equilibrium predictions. Photochemistry can also be important on such planets, with CO2 and HCN being key photochemical products. Carbon dioxide becomes a major constituent when stratospheric temperatures are low and recycling of water via the {{{H}}}2 + OH reaction becomes kinetically stifled. Young Jupiters with effective temperatures ≲ 700 K are in a particularly interesting photochemical regime that differs from both transiting hot Jupiters and our own solar-system giant planets.

  17. The atmospheres of earthlike planets after giant impact events

    SciTech Connect

    Lupu, R. E.; Freedman, Richard; Schaefer, Laura; Morley, Caroline; Fortney, Jonathan J.; Cahoy, Kerri

    2014-03-20

    It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO{sub 2} and H{sub 2}O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere, and oceans) or Earth's continental crust. We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H{sub 2}O and CO{sub 2}, while the formation of CH{sub 4} and NH{sub 3} is quenched because of short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO{sub 2}. These are apparent in the emerging spectra and can be indicative that an impact has occurred. The use of comprehensive opacities results in spectra that are a factor of two lower brightness temperature in the spectral windows than predicted by previous models. The estimated luminosities show that the hottest post-giant-impact planets will be detectable with near-infrared coronagraphs on the planned 30 m class telescopes. The 1-4 μm will be most favorable for such detections, offering bright features and better contrast between the planet and a potential debris disk. We derive cooling timescales on the order of 10{sup 5-6} yr on the basis of the modeled effective temperatures. This leads to the possibility of discovering tens of such planets in future surveys.

  18. Investigating the link between composition and evolution of giant planets

    NASA Astrophysics Data System (ADS)

    Turrini, Diego; Altieri, Francesca; Grassi, Davide; D'Aversa, Emiliano; Adriani, Alberto; Piccioni, Giuseppe; Bellucci, Giancarlo; Filacchione, Gianrico; Micela, Giusi

    2013-04-01

    In the recent years, thanks to ground-based and space-based observations, the number of discovered exoplanets orbiting other stars has greatly increased. As a consequence, the focus in the exoplanetary quest for knowledge is starting to shift from their discovery to their characterization. The composition of exoplanets, in fact, is linked to the formation and evolution of the systems that host them. As in all inverse problems, however, such a link is not easy to unfold. As is shown by the case of our solar system, giant planets offer a unique opportunity to investigate the relationship between formation, evolution and atmospheric composition. The Galileo and Cassini missions, in fact, have revealed that the atmospheric and bulk composition of Jupiter and Saturn significantly deviate from the originally expected ones, each planet being characterized by different enrichment factors in high-Z elements. Different mechanisms have been proposed to explain these deviations, but the Solar System alone does not supply enough constraints to solve this problem. The aim of this work is to investigate how the tools and models developed for the case of the Solar System can be applied to the study of extrasolar planets and shed new light on the early evolution of forming planetary systems. Using N-body simulations that account for the growth and the migration of giant planets and considering a selected sample of observed single-planet extrasolar systems as test cases, we will assess what are the sources and the composition of the material accreted by the forming giant planets and its effects on their atmospheric composition.

  19. Meeting contribution: Bright lights on giant planets

    NASA Astrophysics Data System (ADS)

    Miller, S.

    2007-04-01

    Prof Miller explained that his scientific background was in chemistry rather than astronomy, but that he had become involved with planetary science, and especially aurorae, through an interest in the chemical composition of planetary atmospheres. The various colours seen in aurorae were powerful probes of the chemical constituents of atmospheres, and the speaker illustrated this with an image of the aurora borealis of our own planet. The deep red emission seen at the highest celestial altitudes could be attributed to atomic oxygen, and likewise the brighter green emission below it. Towards the lower edge of the aurora, closest to the horizon, reddish-pink emission stemmed from molecular nitrogen.

  20. Model Atmospheres and Spectra for Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Freedman, Richard S.; Beebe, Reta (Technical Monitor)

    2000-01-01

    In the past few years much new observational data has become available for brown dwarfs and extra solar planets. Not only are new objects being discovered but the availability of higher resolution spectra is improving. This allows a better comparison between the models and the available data, and places new constraints on the models which now have to be made more physically realistic in order to better interpret the observations. Under this grant, an array of new opacities were calculated and successfully applied to a variety of physical situations that were used as input to model available observations of brown dwarfs and extra solar giant planets.

  1. Gas Giant Planet Formation in the Photoevaporating Disk. I. Gap Formation

    NASA Astrophysics Data System (ADS)

    Xiao, Lin; Jin, Liping; Liu, Chengzhi; Fan, Cunbo

    2016-08-01

    Planet formation and photoevaporation have both been considered as gap opening mechanisms in protoplanetary disks. We have studied giant planet formation in a photoevaporating disk with long-term evolution. Our calculations suggest that the core accretion rate of a protoplanet declines and the trigger of the runaway gas accretion for a giant planet is delayed under the action of photoevaporation. We find that the final mass of a giant planet characterized by the “gap-limiting” case is not influenced by photoevaporation but the final mass of a giant planet characterized by the “diffusion-limiting” case is greatly influenced by photoevaporation. Considering the formation process of giant planets, we suggest that the locations of the gaps opened by giant planets are within 30-40 au and the gap width in the “gap-limiting” case is wider than that in the “diffusion-limiting” case. We also find that gaps in photoevaporating disks are wider than those in non-photoevaporating disks. Our calculations suggest that the origins of multiple gaps in a disk can be diverse depending on their formation locations. In the formation region of giant planets, gaps are opened by giant planets. The outer gap beyond the giant planet formation region may be opened under the action of photoevaporation. A gap may also be opened at 1-3 au under the actions of photoevaporating dissipation and gas accretion of the outer giant planets.

  2. Exploring the Relationship Between Planet Mass and Atmospheric Metallicity for Cool Giant Planets

    NASA Astrophysics Data System (ADS)

    Thomas, Nancy H.; Wong, Ian; Knutson, Heather; Deming, Drake; Desert, Jean-Michel; Fortney, Jonathan J.; Morley, Caroline; Kammer, Joshua A.; Line, Michael R.

    2016-10-01

    Measurements of the average densities of exoplanets have begun to help constrain their bulk compositions and to provide insight into their formation locations and accretionary histories. Current mass and radius measurements suggest an inverse relationship between a planet's bulk metallicity and its mass, a relationship also seen in the gas and ice giant planets of our own solar system. We expect atmospheric metallicity to similarly increase with decreasing planet mass, but there are currently few constraints on the atmospheric metallicities of extrasolar giant planets. For hydrogen-dominated atmospheres, equilibrium chemistry models predict a transition from CO to CH4 below ~1200 K. However, with increased atmospheric metallicity the relative abundance of CH4 is depleted and CO is enhanced. In this study we present new secondary eclipse observations of a set of cool (<1200 K) giant exoplanets at 3.6 and 4.5 microns using the Spitzer Space Telescope, which allow us to constrain their relative abundances of CH4 and CO and corresponding atmospheric metallicities. We discuss the implications of our results for the proposed correlation between planet mass and atmospheric metallicity as predicted by the core accretion models and observed in our solar system.

  3. Oxygen in the stratospheres of the giant planets and Titan

    NASA Astrophysics Data System (ADS)

    Feuchtgruber, H.; Lellouch, E.; Encrenaz, Th.; Bezard, B.; Coustenis, A.; Drossart, P.; Salama, A.; de Graauw, Th.; Davis, G. R.

    1999-03-01

    Infrared spectra of the Short-Wavelength Spectrometer (SWS) of ISO at wavelengths between 25 - 45 μm have provided the first detection of stratospheric H2O on all four giant planets and Titan. Together with SWS observations of CO2 at 14.98 μm, leading to first detections on Neptune, Saturn and Jupiter an external source of oxygen is required to explain the derived upper stratospheric mixing ratios of up to several ppb at mbar-μbar levels. We provide an overview on the required amounts of external oxygen fluxes and a detailed discussion on the various scenarios for the origin of CO2 in the stratospheres of the giant planets.

  4. Europa, tidally heated oceans, and habitable zones around giant planets

    NASA Technical Reports Server (NTRS)

    Reynolds, Ray T.; Mckay, Christopher P.; Kasting, James F.

    1987-01-01

    Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. Europa could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such a case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of eons and in which life could perhaps evolve. A zone around a giant planet is defined in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In this solar system, this radiatively-heated habitable zone contains the earth.

  5. Giant Planet Accretion in a Low-Turbulence Circumplanetary Disk

    NASA Astrophysics Data System (ADS)

    D'Angelo, Gennaro; Marzari, Francesco

    2014-06-01

    At least 5% of confirmed planets discovered by the Kepler Mission have a mass greater than Jupiter's. Gas giants more massive than Saturn account for at least 18% of all confirmed planets.The final stages of gas accretion of a giant planet occur in the presence of a circumplanetary disk (CPD). Recently, it was proposed that turbulence (and hence transport) in these disks is driven by MRI, possibly generating low-turbulence regions known as Dead Zones. It was thus suggested that gas accretion through a CPD and on the planet can be severely reduced by a Dead Zone. If CPDs create a bottleneck for the accretion of gas, then the growth of planets more massive than Jupiter may become problematic.We investigate how gas accretion on a Jupiter-mass planet is affected by a Dead Zone by means of global 3D hydrodynamics calculations. We model both the CPD and the protoplanetary disk. The accretion flow is resolved at a length scale smaller than Jupiter's radius, Rj, by using a nested-grid technique. We assume that the kinematic viscosity is constant and equal to nu=1e-5 Omega a^2, where a and Omega are respectively the planet's orbital radius and frequency. A Dead Zone around the planet is represented by a region of low viscosity (nu=1e-8 Omega a^2), extending out to ~60Rj and above and below the CPD mid-plane for a few local scale heights. We obtain an accretion rate of ~5e-5 Omega Sigma a^2, where Sigma is the unperturbed protoplanetary disk density. Calculations by D'Angelo et al. (2003) and Bate et al. (2003), which used nu=1e-5 Omega a^2 everywhere but applied a much coarser resolution and different accretion parameters, found an accretion rate of ~2e-4 Omega Sigma a^2. Accounting for variations of several tens of percent, arising from differences (between these and previous calculations) in numerical parameters and resolution, we argue that a CPD Dead Zone, as modeled here, does not significantly affect the gas accretion rate of a giant planet. This result is compatible

  6. Terrestrial planets in high-mass disks without gas giants

    NASA Astrophysics Data System (ADS)

    de Elía, G. C.; Guilera, O. M.; Brunini, A.

    2013-09-01

    Context. Observational and theoretical studies suggest that planetary systems consisting only of rocky planets are probably the most common in the Universe. Aims: We study the potential habitability of planets formed in high-mass disks without gas giants around solar-type stars. These systems are interesting because they are likely to harbor super-Earths or Neptune-mass planets on wide orbits, which one should be able to detect with the microlensing technique. Methods: First, a semi-analytical model was used to define the mass of the protoplanetary disks that produce Earth-like planets, super-Earths, or mini-Neptunes, but not gas giants. Using mean values for the parameters that describe a disk and its evolution, we infer that disks with masses lower than 0.15 M⊙ are unable to form gas giants. Then, that semi-analytical model was used to describe the evolution of embryos and planetesimals during the gaseous phase for a given disk. Thus, initial conditions were obtained to perform N-body simulations of planetary accretion. We studied disks of 0.1, 0.125, and 0.15 M⊙. Results: All our simulations form massive planets on wide orbits. For a 0.1 M⊙ disk, 2-3 super-Earths of 2.8 to 5.9 M⊕ are formed between 2 and 5 AU. For disks of 0.125 and 0.15 M⊙, our simulations produce a 10-17.1 M⊕ planet between 1.6 and 2.7 AU, and other super-Earths are formed in outer regions. Moreover, six planets survive in the habitable zone (HZ). These planets have masses from 1.9 to 4.7 M⊕ and significant water contents ranging from 560 to 7482 Earth oceans, where one Earth ocean represents the amount of water on Earth's surface, which equals 2.8 × 10-4M⊕. Of the six planets formed in the HZ, three are water worlds with 39%-44% water by mass. These planets start the simulations beyond the snow line, which explains their high water abundances. In general terms, the smaller the mass of the planets observed on wide orbits, the higher the possibility to find water worlds in the

  7. Differential Astrometry to detect giant planets around A-stars

    NASA Astrophysics Data System (ADS)

    Monnier, John D.; Johnson, Keith; Swihart, Samuel; Ireland, Michael; Zhao, Ming; Ten Brummelaar, Theo

    2015-01-01

    The exoplanet field has remained vibrant and exciting due to the continuous development of new observing techniques and the refinement of older ones, both from the ground and from space. Here we propose to push the exoplanet frontier through the development of a new interferometric experiment that takes advantage of the Michigan Infrared Combiner (MIRC) on the CHARA Array, a visible and near-infrared interferometer boasting the longest baselines and finest angular resolution in the world. The ARMADA (ARrangement for Micro-Arcsecond Differential Astrometry) Project will search for astrometric wobble in a sample of hot stars (spectral type A,B) to search for giants planets in P<3 year orbits. Recent radial velocity (RV) work studying evolved sub-giants --``retired A stars" -- suggest up to a five-fold increase in the presence of massive gas giant planets in about 1 AU orbits compared to solar-type stars. Confirmation of this disputed result on A stars themselves would have profound effect on theories of planet formation but is difficult or impossible due to the broad, weak lines of hot stars. Using a novel etalon module already designed and fabricated to maintain precision wavelength calibration (Dl/l ~1x10-5), we aim to measure separations with <10 micro-arcsecond-level precision for binaries up to 0.25' separation.

  8. Giant Planet Formation by Disk Instability in Low Mass Disks?

    NASA Astrophysics Data System (ADS)

    Boss, Alan P.

    2010-12-01

    Forming giant planets by disk instability requires a gaseous disk that is massive enough to become gravitationally unstable and able to cool fast enough for self-gravitating clumps to form and survive. Models with simplified disk cooling have shown the critical importance of the ratio of the cooling to the orbital timescales. Uncertainties about the proper value of this ratio can be sidestepped by including radiative transfer. Three-dimensional radiative hydrodynamics models of a disk with a mass of 0.043 M sun from 4 to 20 AU in orbit around a 1 M sun protostar show that disk instabilities are considerably less successful in producing self-gravitating clumps than in a disk with twice this mass. The results are sensitive to the assumed initial outer disk (To ) temperatures. Models with To = 20 K are able to form a single self-gravitating clump, whereas models with To = 25 K form clumps that are not quite self-gravitating. These models imply that disk instability requires a disk with a mass of at least ~0.043 M sun inside 20 AU in order to form giant planets around solar-mass protostars with realistic disk cooling rates and outer-disk temperatures. Lower mass disks around solar-mass protostars must rely upon core accretion to form inner giant planets.

  9. Giant planet formation in radially structured protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Coleman, Gavin A. L.; Nelson, Richard P.

    2016-08-01

    Our recent N-body simulations of planetary system formation, incorporating models for the main physical processes thought to be important during the building of planets (i.e. gas disc evolution, migration, planetesimal/boulder accretion, gas accretion on to cores, etc.), have been successful in reproducing some of the broad features of the observed exoplanet population (e.g. compact systems of low-mass planets, hot Jupiters), but fail completely to form any surviving cold Jupiters. The primary reason for this failure is rapid inward migration of growing protoplanets during the gas accretion phase, resulting in the delivery of these bodies on to orbits close to the star. Here, we present the results of simulations that examine the formation of gas giant planets in protoplanetary discs that are radially structured due to spatial and temporal variations in the effective viscous stresses, and show that such a model results in the formation of a population of cold gas giants. Furthermore, when combined with models for disc photoevaporation and a central magnetospheric cavity, the simulations reproduce the well-known hot-Jupiter/cold-Jupiter dichotomy in the observed period distribution of giant exoplanets, with a period valley between 10 and 100 d.

  10. MIGRATION OF GAS GIANT PLANETS IN GRAVITATIONALLY UNSTABLE DISKS

    SciTech Connect

    Michael, Scott; Durisen, Richard H.; Boley, Aaron C. E-mail: durisen@astro.indiana.edu

    2011-08-20

    Characterization of migration in gravitationally unstable disks is necessary to understand the fate of protoplanets formed by disk instability. As part of a larger study, we are using a three-dimensional radiative hydrodynamics code to investigate how an embedded gas giant planet interacts with a gas disk that undergoes gravitational instabilities (GIs). This Letter presents results from simulations with a Jupiter-mass planet placed in orbit at 25 AU within a 0.14 M{sub sun} disk. The disk spans 5-40 AU around a 1 M{sub sun} star and is initially marginally unstable. In one simulation, the planet is inserted prior to the eruption of GIs; in another, it is inserted only after the disk has settled into a quasi-steady GI-active state, where heating by GIs roughly balances radiative cooling. When the planet is present from the beginning, its own wake stimulates growth of a particular global mode with which it strongly interacts, and the planet plunges inward 6 AU in about 10{sup 3} years. In both cases with embedded planets, there are times when the planet's radial motion is slow and varies in direction. At other times, when the planet appears to be interacting with strong spiral modes, migration both inward and outward can be relatively rapid, covering several AUs over hundreds of years. Migration in both cases appears to stall near the inner Lindblad resonance of a dominant low-order mode. Planet orbit eccentricities fluctuate rapidly between about 0.02 and 0.1 throughout the GI-active phases of the simulations.

  11. How empty are disk gaps opened by giant planets?

    SciTech Connect

    Fung, Jeffrey; Shi, Ji-Ming; Chiang, Eugene

    2014-02-20

    Gap clearing by giant planets has been proposed to explain the optically thin cavities observed in many protoplanetary disks. How much material remains in the gap determines not only how detectable young planets are in their birth environments, but also how strong co-rotation torques are, which impacts how planets can survive fast orbital migration. We determine numerically how the average surface density inside the gap, Σ{sub gap}, depends on planet-to-star mass ratio q, Shakura-Sunyaev viscosity parameter α, and disk height-to-radius aspect ratio h/r. Our results are derived from our new graphics processing unit accelerated Lagrangian hydrodynamical code PEnGUIn and are verified by independent simulations with ZEUS90. For Jupiter-like planets, we find Σ{sub gap}∝q {sup –2.2}α{sup 1.4}(h/r){sup 6.6}, and for near brown dwarf masses, Σ{sub gap}∝q {sup –1}α{sup 1.3}(h/r){sup 6.1}. Surface density contrasts inside and outside gaps can be as large as 10{sup 4}, even when the planet does not accrete. We derive a simple analytic scaling, Σ{sub gap}∝q {sup –2}α{sup 1}(h/r){sup 5}, that compares reasonably well to empirical results, especially at low Neptune-like masses, and use discrepancies to highlight areas for progress.

  12. Impact cratering of the terrestrial planets and the Moon during the giant planet instability

    NASA Astrophysics Data System (ADS)

    Roig, Fernando Virgilio; Nesvorny, David; Bottke, William

    2016-10-01

    The dynamical instability of the giant planets and the planetesimal driven migration both have major implications for the crater record of the terrestrial planets and the Moon. The crater record can thus provide contraints to the behavior of the planets in the early Solar System. Here we determine the impact fluxes and the crater production rates on the terrestrial planets and the Moon from impactors originating in the primordial asteroid main belt (2.1 to 3.2 au) and the E-belt (1.5 to 2.1 au - Bottke et al. 2012). We determine the impact flux over the age of the Solar System, with particular focus on the instability of the giant planets in the jumping Jupiter model. We start with a population of asteroids uniformly distributed in the orbital parameters space, and numerically evolve them as test particles under the gravitational perturbations of the giant and terrestrial planets. We test the effects on this population due to different jumping Jupiter evolutions (the idealized jump as in Bottke et al. 2012 or models taken from Nesvorny & Morbidelli 2012). The number of impacts is determined by applying Opik's theory. We compute the impact rates on different targets (Mercury, Venus, Earth, Moon, and Mars) and from different source regions in the asteroid belt (E-belt, inner belt, outer belt). By properly calibrating the impact rates, and using crater scaling laws, we estimate the number and size distribution of craters. We show how the impact flux and crater production rates depend on the different parameters of the model such as the initial orbital distribution of the asteroids, time of the instability, different evolution of the planets, initial size distribution of the impactors, etc.

  13. Are Giant Planet Satellites Mini-solar Systems?

    NASA Astrophysics Data System (ADS)

    Mosqueira, I.; Estrada, P. R.

    2003-12-01

    The regular satellites of Jupiter and Saturn exhibit a number of characteristics strongly suggestive of formation in a thin (aspect ratio H/r ˜ 0.1) circumplanetary gas disk (Mosqueira and Estrada 2003a). Also, the mass ratio of the largest satellites to the primary μ ˜ 10-4 lead one to think of these satellite systems as scaled-down solar systems. Yet, the larger mass ratio for the giant planets to the primary μ ˜ 10-3 appears to limit the usefulness of the planet-satellite analogy. If gap-opening determines the final size of at least Jupiter (Lin and Papaloizou 1993), then significantly smaller objects would be unable to truncate the disk. There are, however, at least two significant difficulties with this point of view. First, the non-linear or thermal gap-opening criterion (Lin and Papaloizou 1993) does not yield a Jupiter mass. Second, the migration timescale due to planet-disk interactions (Ward 1997) is too fast for the formation of giant planets through the core accretion process (Pollack et. al 1996) despite recent work which has lengthened it by up to an order of magnitude (Tanaka et al. 2002, D'Angelo et al. 2002, Bate et al. 2003). An alternative viewpoint has accretion taking place in a weakly turbulent disk, and the survival of both planets and satellites a direct consequence of gap-opening. In this view at least the largest satellites (Mosqueira and Estrada 2003b) and planetary cores ( ˜ 10 M⊕ ; Rafikov 2002) were able to open gaps in the disk. However, because the waves launched by such pertubers do not become non-linear immediately, the gap begins to form a distance away from the perturber given by the shocking length of acoustic waves (Goodman and Rafikov 2001; Rafikov 2002). Estrada and Mosqueira (2003) have suggested that the annulus of material adjacent to the proto-planet that immediately precedes the runaway gas accretion phase (Pollack et al. 1996) can be used to provide the mass needed to lead to the formation of a giant planet. If

  14. Giant Planet Candidates, Brown Dwarfs, and Binaries from the SDSS-III MARVELS Planet Survey.

    NASA Astrophysics Data System (ADS)

    Thomas, Neil; Ge, Jian; Li, Rui; de Lee, Nathan M.; Heslar, Michael; Ma, Bo; SDSS-Iii Marvels Team

    2015-01-01

    We report the discoveries of giant planet candidates, brown dwarfs, and binaries from the SDSS-III MARVELS survey. The finalized 1D pipeline has provided 18 giant planet candidates, 16 brown dwarfs, and over 500 binaries. An additional 96 targets having RV variability indicative of a giant planet companion are also reported for future investigation. These candidates are found using the advanced MARVELS 1D data pipeline developed at UF from scratch over the past three years. This pipeline carefully corrects most of the instrument effects (such as trace, slant, distortion, drifts and dispersion) and observation condition effects (such as illumination profile, fiber degradation, and tracking variations). The result is long-term RV precisions that approach the photon limits in many cases for the ~89,000 individual stellar observations. A 2D version of the pipeline that uses interferometric information is nearing completion and is demonstrating a reduction of errors to half the current levels. The 2D processing will be used to increase the robustness of the detections presented here and to find new candidates in RV regions not confidently detectable with the 1D pipeline. The MARVELS survey has produced the largest homogeneous RV measurements of 3300 V=7.6-12 FGK stars with a well defined cadence of 27 RV measurements over 2 years. The MARVELS RV data and other follow-up data (photometry, high contrast imaging, high resolution spectroscopy and RV measurements) will explore the diversity of giant planet companion formation and evolution around stars with a broad range in metallicity (Fe/H -1.5-0.5), mass ( 0.6-2.5M(sun)), and environment (thin disk and thick disk), and will help to address the key scientific questions identified for the MARVELS survey including, but not limited to: Do metal poor stars obey the same trends for planet occurrence as metal rich stars? What is the distribution of giant planets around intermediate-mass stars and binaries? Is the 'planet desert

  15. TERRESTRIAL PLANET FORMATION DURING THE MIGRATION AND RESONANCE CROSSINGS OF THE GIANT PLANETS

    SciTech Connect

    Lykawka, Patryk Sofia; Ito, Takashi

    2013-08-10

    The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a {approx} 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths)

  16. Terrestrial Planet Formation during the Migration and Resonance Crossings of the Giant Planets

    NASA Astrophysics Data System (ADS)

    Lykawka, Patryk Sofia; Ito, Takashi

    2013-08-01

    The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ~ 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths).

  17. Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets

    NASA Astrophysics Data System (ADS)

    Lykawka, Patryk S.; Ito, T.

    2013-10-01

    The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ~1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter’s and Saturn’s more eccentric orbits (relative to present-day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars’ mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars’ small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths).

  18. Scenarios of giant planet formation and evolution and their impact on the formation of habitable terrestrial planets.

    PubMed

    Morbidelli, Alessandro

    2014-04-28

    In our Solar System, there is a clear divide between the terrestrial and giant planets. These two categories of planets formed and evolved separately, almost in isolation from each other. This was possible because Jupiter avoided migrating into the inner Solar System, most probably due to the presence of Saturn, and never acquired a large-eccentricity orbit, even during the phase of orbital instability that the giant planets most likely experienced. Thus, the Earth formed on a time scale of several tens of millions of years, by collision of Moon- to Mars-mass planetary embryos, in a gas-free and volatile-depleted environment. We do not expect, however, that this clear cleavage between the giant and terrestrial planets is generic. In many extrasolar planetary systems discovered to date, the giant planets migrated into the vicinity of the parent star and/or acquired eccentric orbits. In this way, the evolution and destiny of the giant and terrestrial planets become intimately linked. This paper discusses several evolutionary patterns for the giant planets, with an emphasis on the consequences for the formation and survival of habitable terrestrial planets. The conclusion is that we should not expect Earth-like planets to be typical in terms of physical and orbital properties and accretion history. Most habitable worlds are probably different, exotic worlds. PMID:24664911

  19. Scenarios of giant planet formation and evolution and their impact on the formation of habitable terrestrial planets.

    PubMed

    Morbidelli, Alessandro

    2014-04-28

    In our Solar System, there is a clear divide between the terrestrial and giant planets. These two categories of planets formed and evolved separately, almost in isolation from each other. This was possible because Jupiter avoided migrating into the inner Solar System, most probably due to the presence of Saturn, and never acquired a large-eccentricity orbit, even during the phase of orbital instability that the giant planets most likely experienced. Thus, the Earth formed on a time scale of several tens of millions of years, by collision of Moon- to Mars-mass planetary embryos, in a gas-free and volatile-depleted environment. We do not expect, however, that this clear cleavage between the giant and terrestrial planets is generic. In many extrasolar planetary systems discovered to date, the giant planets migrated into the vicinity of the parent star and/or acquired eccentric orbits. In this way, the evolution and destiny of the giant and terrestrial planets become intimately linked. This paper discusses several evolutionary patterns for the giant planets, with an emphasis on the consequences for the formation and survival of habitable terrestrial planets. The conclusion is that we should not expect Earth-like planets to be typical in terms of physical and orbital properties and accretion history. Most habitable worlds are probably different, exotic worlds.

  20. The Mass - Radius Relation of Giant Gas Planets

    NASA Astrophysics Data System (ADS)

    Çelik Orhan, Zeynep; Kayhan, Cenk; Yildiz, Mutlu

    2016-07-01

    Thanks to CoRoT and Kepler space telescope, the thousand of exoplanets have been discovered. The only observational construct on planetary interior is planetary radius. Mass-radius relation is widely studied in the literature. Many mechanisms have been suggested in the literature to explain the inflated radii of these planets. In this study, our aim is to consider planet and host star interaction and assess the basic mechanisms responsible for excess in radius of transiting giant gas planets. We show that there is much more definite relation between radius and energy per gram per second (log (l- )). There is a good linear relation between planetary radius and log (l- ) for log (l- /l0 ) < 3.75. The relation changes if log (l- /l0 ) > 3.5. There is a relatively clump for the range log (l- /l0 ) > 3.75. The reason for the change in the relation may be related with the structure of the heated part of the planets. We focus on these inflated planet.

  1. Predicting the Atmospheric Composition of Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Sharp, A. G.; Moses, J. I.; Friedson, A. J.; Fegley, B., Jr.; Marley, M. S.; Lodders, K.

    2004-01-01

    To date, approximately 120 planet-sized objects have been discovered around other stars, mostly through the radial-velocity technique. This technique can provide information about a planet s minimum mass and its orbital period and distance; however, few other planetary data can be obtained at this point in time unless we are fortunate enough to find an extrasolar giant planet that transits its parent star (i.e., the orbit is edge-on as seen from Earth). In that situation, many physical properties of the planet and its parent star can be determined, including some compositional information. Our prospects of directly obtaining spectra from extrasolar planets may improve in the near future, through missions like NASA's Terrestrial Planet Finder. Most of the extrasolar giant planets (EGPs) discovered so far have masses equal to or greater than Jupiter's mass, and roughly 16% have orbital radii less than 0.1 AU - extremely close to the parent star by our own Solar-System standards (note that Mercury is located at a mean distance of 0.39 AU and Jupiter at 5.2 AU from the Sun). Although all EGPs are expected to have hydrogen-dominated atmospheres similar to Jupiter, the orbital distance can strongly affect the planet's temperature, physical, chemical, and spectral properties, and the abundance of minor, detectable atmospheric constituents. Thermochemical equilibrium models can provide good zero-order predictions for the atmospheric composition of EGPs. However, both the composition and spectral properties will depend in large part on disequilibrium processes like photochemistry, chemical kinetics, atmospheric transport, and haze formation. We have developed a photochemical kinetics, radiative transfer, and 1-D vertical transport model to study the atmospheric composition of EGPs. The chemical reaction list contains H-, C-, O-, and N-bearing species and is designed to be valid for atmospheric temperatures ranging from 100-3000 K and pressures up to 50 bar. Here we examine

  2. High-latitude circulation in giant planet magnetospheres

    NASA Astrophysics Data System (ADS)

    Southwood, D. J.; Chané, E.

    2016-06-01

    We follow-up the proposal by Cowley et al. (2004) that the plasma circulation in the magnetospheres of the giant planets is a combination of two cycles or circulation systems. The Vasyliunas cycle transports heavy material ionized deep within the magnetosphere eventually to loss in the magnetotail. The second cycle is driven by magnetic reconnection between the planetary and the solar wind magnetic fields (the Dungey cycle) and is found on flux tubes poleward of those of the Vasyliunas cycle. We examine features of the Dungey system, particularly what occurs out of the equatorial plane. The Dungey cycle requires reconnection on the dayside, and we suggest that at the giant planets the dayside reconnection occurs preferentially in the morning sector. Second, we suggest that most of the solar wind material that enters through reconnection on to open flux tubes on the dayside never gets trapped on closed field lines but makes less than one circuit of the planet and exits down tail. In its passage to the nightside, the streaming ex-solar wind material is accelerated centrifugally by the planetary rotation primarily along the field; thus, in the tail it will appear very like a planetary wind. The escaping wind will be found on the edges of the tail plasma sheet, and reports of light ion streams in the tail are likely due to this source. The paper concludes with a discussion of high-latitude circulation in the absence of reconnection between the solar wind and planetary field.

  3. The Properties of Heavy Elements in Giant Planet Envelopes

    NASA Astrophysics Data System (ADS)

    Soubiran, François; Militzer, Burkhard

    2016-09-01

    The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H–He envelope. Late planetesimal accretion and core erosion could potentially enrich the H–He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter’s atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z, in various proportions. However, their effect on the equation of state of the hydrogen–helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H–He–Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO2, we show that the behavior of heavy elements in H–He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature–pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter’s interior by only 80 K.

  4. The Properties of Heavy Elements in Giant Planet Envelopes

    NASA Astrophysics Data System (ADS)

    Soubiran, François; Militzer, Burkhard

    2016-09-01

    The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H-He envelope. Late planetesimal accretion and core erosion could potentially enrich the H-He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter’s atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z, in various proportions. However, their effect on the equation of state of the hydrogen-helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H-He-Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO2, we show that the behavior of heavy elements in H-He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature-pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter’s interior by only 80 K.

  5. H3+: the driver of giant planet atmospheres.

    PubMed

    Miller, Steve; Stallard, Tom; Smith, Chris; Millward, George; Melin, Henrik; Lystrup, Makenzie; Aylward, Alan

    2006-11-15

    We present a review of recent developments in the use of H3+ molecular ion as a probe of physics and chemistry of the upper atmospheres of giant planets. This ion is shown to be a good tracer of energy inputs into Jupiter (J), Saturn (S) and Uranus (U). It also acts as a 'thermostat', offsetting increases in the energy inputs owing to particle precipitation via cooling to space (J and U). Computer models have established that H3+ is also the main contributor to ionospheric conductivity. The coupling of electric and magnetic fields in the auroral polar regions leads to ion winds, which, in turn, drive neutral circulation systems (J and S). These latter two effects, dependent on H3+, also result in very large heating terms, approximately 5 x 10(12) W for Saturn and greater than 10(14) W for Jupiter, planet-wide; these terms compare with approximately 2.5 x 10(11) W of solar extreme UV absorbed at Saturn and 10(12) W at Jupiter. Thus, H3+ is shown to play a major role in explaining why the temperatures of the giant planets are much greater (by hundreds of kelvin) at the top of the atmosphere than solar inputs alone can account for. PMID:17015372

  6. The Gemini Planet-finding Campaign: The Frequency Of Giant Planets around Debris Disk Stars

    NASA Astrophysics Data System (ADS)

    Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Biller, Beth A.; Hayward, Thomas L.; Close, Laird M.; Males, Jared R.; Skemer, Andrew; Ftaclas, Christ; Chun, Mark; Thatte, Niranjan; Tecza, Matthias; Shkolnik, Evgenya L.; Kuchner, Marc; Reid, I. Neill; de Gouveia Dal Pino, Elisabete M.; Alencar, Silvia H. P.; Gregorio-Hetem, Jane; Boss, Alan; Lin, Douglas N. C.; Toomey, Douglas W.

    2013-08-01

    We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.''5 and 14.1 mag at 1'' separation. Follow-up observations of the 66 candidates with projected separation <500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known β Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a >=5 M Jup planet beyond 80 AU, and <21% of debris disk stars have a >=3 M Jup planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly imaged planets as d 2 N/dMdavpropm α a β, where m is planet mass and a is orbital semi-major axis (with a maximum value of a max). We find that β < -0.8 and/or α > 1.7. Likewise, we find that β < -0.8 and/or a max < 200 AU. For the case where the planet frequency rises sharply with mass (α > 1.7), this occurs because all the planets detected to date have masses above 5 M Jup, but planets of lower mass could easily have been detected by our search. If we ignore the β Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a >=3 M Jup planet beyond 10 AU, and β < -0.8 and/or α < -1.5. Likewise, β < -0.8 and/or a max < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet

  7. Exploring our outer solar system - The Giant Planet System Observers

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Sittler, E. C., Jr.; Sturner, S. J.; Pitman, J. T.

    As space-faring peoples now work together to plan and implement future missions that robotically prepare for landing humans to explore the Moon, and later Mars, the time is right to develop evolutionary approaches for extending this next generation of exploration beyond Earth's terrestrial planet neighbors to the realm of the giant planets. And while initial fly-by missions have been hugely successful in providing exploratory surveys of what lies beyond Mars, we need to consider now what robotic precursor mission capabilities we need to emplace that prepare us properly, and comprehensively, for long-term robotic exploration, and eventual human habitation, beyond Mars to the outer reaches of our solar system. To develop practical strategies that can establish prioritized capabilities, and then develop a means for achieving those capabilities within realistic budget and technology considerations, and in reasonable timeframes, is our challenge. We suggest one component of such an approach to future outer planets exploration is a series of Giant Planets System Observer (GPSO) missions that provide for long- duration observations, monitoring, and relay functions to help advance our understanding of the outer planets and thereby enable a sound basis for planning their eventual exploration by humans. We envision these missions as being comparable to taking Hubble-class remote-sensing facilities, along with the space physics capabilities of long-lived geospace and heliospheric missions, to the giant planet systems and dedicating long observing lifetimes (HST, 16 yr.; Voyagers, 29 yr.) to the exhaustive study and characterization of those systems. GPSO missions could feature 20-yr+ extended mission lifetimes, direct inject trajectories to maximize useful lifetime on target, placement strategies that take advantage of natural environment shielding (e.g., Ganymede magnetic field) where possible, orbit designs having favorable planetary system viewing geometries, comprehensive

  8. THE PAN-PACIFIC PLANET SEARCH. I. A GIANT PLANET ORBITING 7 CMa

    SciTech Connect

    Wittenmyer, Robert A.; Tinney, C. G.; Endl, Michael; Wang Liang; Johnson, John Asher; O'Toole, S. J.

    2011-12-20

    We introduce the Pan-Pacific Planet Search, a survey of 170 metal-rich Southern Hemisphere subgiants using the 3.9 m Anglo-Australian Telescope. We report the first discovery from this program, a giant planet orbiting 7 CMa (HD 47205) with a period of 763 {+-} 17 days, eccentricity e = 0.14 {+-} 0.06, and msin i = 2.6 {+-} 0.6 M{sub Jup}. The host star is a K giant with a mass of 1.5 {+-} 0.3 M{sub Sun} and metallicity [Fe/H] = 0.21 {+-} 0.10. The mass and period of 7 CMa b are typical of planets which have been found to orbit intermediate-mass stars (M{sub *} > 1.3 M{sub Sun }). Hipparcos photometry shows this star to be stable to 0.0004 mag on the radial-velocity period, giving confidence that this signal can be attributed to reflex motion caused by an orbiting planet.

  9. Silica Debris Disk Evidence for Giant Planet Forming Impacts

    NASA Astrophysics Data System (ADS)

    Lisse, C.

    2014-04-01

    Giant impacts are major formation events in the history of our solar system. The final assembly of the planets, as we understand it, had to include massive fast collision events as the planets grew to objects with large escape velocities or in regions of high Keplerian velocities (Chambers 2004; Kenyon & Bromley 2004a,b, 2006; Fegley & Schaefer 2005). These massive impact events should create large amounts of glassy silica material derived from the rapid melting, vaporization, and refreezing of normal silicate rich primitive rocky material. We report here the detection of 4 bright silica-rich debris disks in the Spitzer IRS spectral archive, and the possible identification of 7 others. The stellar types of the system primaries span from A5V to G0V, their ages are 10 - 100 Myr, and the dust is warm, 280 - 480 K, and is located between 1.5 and 6 AU, well inside the systems' terrestrial planet regions. The minimum amount of detected 0.1 - 20 dust mass ranges from 10^21 - 10^23 kg; assuming < 10% dust formation efficiency (Benz 2009, 2011) this implies collisions involving impactors massing at least 10^22 - 10^24 kg, i.e. from Moon to Earth mass. We find possible trends in the mineralogy of the silica, with predominantly amorphous silica found in the 2 younger systems, and crystalline silica in the older systems. We speculate this is due higher velocity impacts found in younger, hotter systems, coupled with the effects of energetic photon annealing of small amorphous silica grains. All of these measures are consistent with the creation of silica rich rubble, or construction debris, during the terrestrial planet formation era of giant impacts.

  10. A SEARCH FOR GIANT PLANET COMPANIONS TO T TAURI STARS

    SciTech Connect

    Crockett, Christopher J.; Mahmud, Naved I.; Johns-Krull, Christopher M.; Hartigan, Patrick M.; Prato, L.; Jaffe, Daniel T.; Beichman, Charles A. E-mail: lprato@lowell.edu E-mail: cmj@rice.edu

    2012-12-20

    We present results from an ongoing multiwavelength radial velocity (RV) survey of the Taurus-Auriga star-forming region as part of our effort to identify pre-main-sequence giant planet hosts. These 1-3 Myr old T Tauri stars present significant challenges to traditional RV surveys. The presence of strong magnetic fields gives rise to large, cool star spots. These spots introduce significant RV jitter which can mimic the velocity modulation from a planet-mass companion. To distinguish between spot-induced and planet-induced RV modulation, we conduct observations at {approx}6700 A and {approx}2.3 {mu}m and measure the wavelength dependence (if any) in the RV amplitude. CSHELL observations of the known exoplanet host Gl 86 demonstrate our ability to detect not only hot Jupiters in the near-infrared but also secular trends from more distant companions. Observations of nine very young stars reveal a typical reduction in RV amplitude at the longer wavelengths by a factor of {approx}2-3. While we cannot confirm the presence of planets in this sample, three targets show different periodicities in the two wavelength regions. This suggests different physical mechanisms underlying the optical and the K-band variability.

  11. Extrasolar Giant Planets: Masses and Luminosities from In-situ Formation Theories

    NASA Astrophysics Data System (ADS)

    Wuchterl, G.

    1999-09-01

    Their\\footnoteThis work has been supported by the Oster\\-reichischer Fonds zur Forderung der wissenschaftlichen Forschung (FWF) under project numbers S-7305--AST, S-7307--AST and the Deutsche Forschungsgemeinschaft (DFG), SFB 359 (key research project of the german national science foundation on `Reactive flows, diffusion and transport'). expected luminosities make young giant planets favorable for the first direct detection of an extrasolar planet. The giant planet formation process is relatively slow with expected formation times ranging from comparable to the star formation timescale up to the nebula lifetime, depending on the formation theory. Therefore quantitative models of giant planet formation have to be considered when estimating young giant planet properties at pre-main sequence stellar ages. This is especially important for free-floating giant planet candidates where planetary nature is inferred from luminosities, without independent mass determinations. I will discuss observables of young- and proto-giant planets as they follow from the disk-instability and nucleated-instability hypothesis, respectively. The luminosity exceeds 10(-4) solar luminosities, even for a Saturn-mass protoplanet, during the brief, 30000 year period around maximum accretion. Luminosity maxima of giant planets occur at ages of 1-10 Myr, depending on the details of the formation process. To infer planetary nature in a young population, the properties of young planets have to be compared to those of proto brown dwarfs, as they follow from the respective formation theories.

  12. Extrasolar Giant Planets: Masses and Luminosities from In-Situ Formation Theories

    NASA Astrophysics Data System (ADS)

    Wuchterl, Günther

    Their expected luminosities make young giant planets favorable for the first direct detection of an extrasolar planet. The giant planet formation process is relatively slow with expected formation times ranging from comparable to the star formation timescale up to the nebula lifetime, depending on the formation theory. Therefore quantitative models of giant planet formation have to be considered when estimating young giant planet properties at pre-main sequence stellar ages. This is especially important for free-floating giant planet candidates where planetary nature is inferred from luminosities, without independent mass determinations. I will discuss observables of young- and proto-giant planets as they follow from the disk-instability and nucleated-instability hypothesis, respectively. The luminosity exceeds 10-4 L_⊙, even for a Saturn-mass protoplanet, during the brief, 3 10^4 year period around maximum accretion. Luminosity maxima of giant planets occur at ages of 1-10 Myr, depending on the details of the formation process. To infer planetary nature in a young population, the properties of young planets have to be compared to those of proto brown dwarfs, as they follow from the respective formation theories.

  13. Orbital characterization of the β Pictoris b giant planet

    NASA Astrophysics Data System (ADS)

    Chauvin, G.; Lagrange, A.-M.; Beust, H.; Bonnefoy, M.; Boccaletti, A.; Apai, D.; Allard, F.; Ehrenreich, D.; Girard, J. H. V.; Mouillet, D.; Rouan, D.

    2012-06-01

    Context. In June 2010, we confirmed the existence of a giant planet in the disk of the young star βPictoris located between 8 AU and 15 AU from the star. This young planet offers the rare opportunity to monitor a large fraction of the orbit using the imaging technique over a reasonably short timescale. It also offers the opportunity to study its atmospheric properties using spectroscopy and multi-band photometry, and possibly derive its dynamical mass by combining imaging with radial velocity data to set tight constraints on giant planet formation theories. Aims: We aim to measure the evolution of the planet's position relative to the star βPictoris to determine the planetary orbital properties. Our ultimate goal is to relate both the planetary orbital configuration and physical properties to either the disk structure or the cometary activity observed for decades in the βPictoris system. Methods: Using the NAOS-CONICA adaptive-optics instrument (NACO) at the Very Large Telescope (VLT), we obtained repeated follow-up images of the βPictoris system in the Ks and L' filters at four new epochs in 2010 and 2011. Complementing these data with previous measurements, we conduct a homogeneous analysis, which covers more than eight yrs, to accurately monitor the βPictoris b position relative to the star. We then carefully consider the various sources of uncertainties that may affect the orbital parameter determination. Results: On the basis of the evolution of the planet's relative position with time, we derive the best-fit orbital solutions for our measurements using two fitting methods, a least squares Levenberg-Marquardt algorithm and a Markov-chain Monte Carlo approach. More reliable results are found with the second approach as our measurements do not cover the complete planetary orbit, and are biased toward the most recent epochs since the planet recovery. The solutions favor a low-eccentricity orbit e ≲ 0.17, with semi-major axis in the range 8-9 AU

  14. Detection of Hot Earths by Giant Planet Transit Tming

    NASA Astrophysics Data System (ADS)

    Deming, Drake; Jennings, Donald E.; Sada, Pedro

    2008-08-01

    Many exoplanet systems contain Jupiter-mass planets on close-in orbits. Theories of planetary system formation account for these hot Jupiters as being end states of inward migration. Variants of those theories also predict terrestrial planets to be captured in mean motion resonance with the hot Jupiters. A recent explosion of discoveries by transit surveys have given us a sample of 25 hot Jupiters transiting stars brighter than V=13. A transit timing survey of these systems could detect hot Earths in resonance, via the large (typically 180 second) perturbations they induce on the giant planet transits. The relatively large sample now available implies that a transit timing survey is well matched to classical observing and telescope scheduling. We propose exploratory observations to perform transit photometry using the 2.1-meter/FLAMINGOS instrument in the J-band, where stellar limb darkening is minimal and transit photometry has maximum sensitivity to shifts in transit time. If our exploratory observations confirm timing precision approaching the predicted values (about 10 seconds for a typical system), we will propose additional observations in later semesters to establish a timing survey.

  15. Giant planets: Clues on current and past organic chemistry in the outer solar system

    NASA Technical Reports Server (NTRS)

    Pollack, James B.; Atreya, Sushil K.

    1992-01-01

    The giant planets of the outer solar system - Jupiter, Saturn, Uranus, and Neptune - were formed in the same flattened disk of gas and dust, the solar nebula, as the terrestrial planets were. Yet, the giant planets differ in some very fundamental ways from the terrestrial planets. Despite enormous differences, the giant planets are relevant to exobiology in general and the origin of life on the Earth in particular. The giant planets are described as they are today. Their basic properties and the chemistry occurring in their atmospheres is discussed. Theories of their origin are explored and aspects of these theories that may have relevance to exobiology and the origin of life on Earth are stressed.

  16. PLANETS AROUND THE K-GIANTS BD+20 274 AND HD 219415

    SciTech Connect

    Gettel, S.; Wolszczan, A.; Niedzielski, A.; Nowak, G.; Adamow, M.; Zielinski, P.; Maciejewski, G. E-mail: alex@astro.psu.edu

    2012-09-01

    We present the discovery of planet-mass companions to two giant stars by the ongoing Penn State-Torun Planet Search conducted with the 9.2 m Hobby-Eberly Telescope. The less massive of these stars, K5-giant BD+20 274, has a 4.2 M{sub J} minimum mass planet orbiting the star at a 578 day period and a more distant, likely stellar-mass companion. The best currently available model of the planet orbiting the K0-giant HD 219415 points to a {approx}> Jupiter-mass companion in a 5.7 year, eccentric orbit around the star, making it the longest period planet yet detected by our survey. This planet has an amplitude of {approx}18 m s{sup -1}, comparable to the median radial velocity 'jitter', typical of giant stars.

  17. Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity

    NASA Astrophysics Data System (ADS)

    Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas

    2015-02-01

    Context. We have obtained precise radial velocities for a sample of 373 G and K type giants at Lick Observatory regularly over more than 12 years. Planets have been identified around 15 of these giant stars, and an additional 20 giant stars host planet candidates. Aims: We are interested in the occurrence rate of substellar companions around giant stars as a function of stellar mass and metallicity. We probe the stellar mass range from approximately 1 to beyond 3 M⊙, which is not being explored by main-sequence samples. Methods: We fit the giant planet occurrence rate as a function of stellar mass and metallicity with a Gaussian and an exponential distribution, respectively. Results: We find strong evidence for a planet-metallicity correlation among the secure planet hosts of our giant star sample, in agreement with the one for main-sequence stars. However, the planet-metallicity correlation is absent for our sample of planet candidates, raising the suspicion that a good fraction of them might indeed not be planets despite clear periodicities in the radial velocities. Consistent with the literature results for subgiants, the giant planet occurrence rate increases in the stellar mass interval from 1 to 1.9 M⊙. However, there is a maximum at a stellar mass of 1.9+ 0.1-0.5 M⊙, and the occurrence rate drops rapidly for masses larger than 2.5-3.0 M⊙. We do not find any planets around stars more massive than 2.7 M⊙, although there are 113 stars with masses between 2.7 and 5 M⊙ in our sample (corresponding to a giant planet occurrence rate smaller than 1.6% at 68.3% confidence in that stellar mass bin). We also show that this result is not a selection effect related to the planet detectability being a function of the stellar mass. Conclusions: We conclude that giant planet formation or inward migration is suppressed around higher mass stars, possibly because of faster disk depletion coupled with a longer migration timescale. Based on observations collected at

  18. A DEFINITION FOR GIANT PLANETS BASED ON THE MASS–DENSITY RELATIONSHIP

    SciTech Connect

    Hatzes, Artie P.; Rauer, Heike E-mail: Heike.Rauer@dlr.de

    2015-09-10

    We present the mass–density relationship (log M − log ρ) for objects with masses ranging from planets (M ≈ 0.01 M{sub Jup}) to stars (M > 0.08 M{sub ⊙}). This relationship shows three distinct regions separated by a change in slope in the log M − log ρ plane. In particular, objects with masses in the range 0.3 M{sub Jup}–60 M{sub Jup} follow a tight linear relationship with no distinguishing feature to separate the low-mass end (giant planets) from the high-mass end (brown dwarfs). We propose a new definition of giant planets simply based on changes in the slope of the log M versus log ρ relationship. By this criterion, objects with masses less than ≈0.3 M{sub Jup} are low-mass planets, either icy or rocky. Giant planets cover the mass range 0.3 M{sub Jup}–60 M{sub Jup}. Analogous to the stellar main sequence, objects on the upper end of the giant planet sequence (brown dwarfs) can simply be referred to as “high-mass giant planets,” while planets with masses near that of Jupiter can be called “low-mass giant planets.”.

  19. Numerical simulation of experiments in the Giant Planet Facility

    NASA Technical Reports Server (NTRS)

    Green, M. J.; Davy, W. C.

    1979-01-01

    Utilizing a series of existing computer codes, ablation experiments in the Giant Planet Facility are numerically simulated. Of primary importance is the simulation of the low Mach number shock layer that envelops the test model. The RASLE shock-layer code, used in the Jupiter entry probe heat-shield design, is adapted to the experimental conditions. RASLE predictions for radiative and convective heat fluxes are in good agreement with calorimeter measurements. In simulating carbonaceous ablation experiments, the RASLE code is coupled directly with the CMA material response code. For the graphite models, predicted and measured recessions agree very well. Predicted recession for the carbon phenolic models is 50% higher than that measured. This is the first time codes used for the Jupiter probe design have been compared with experiments.

  20. The extraordinary voyages through the region of the giant planets

    NASA Astrophysics Data System (ADS)

    Danloux-Dumesnils, M.

    1983-01-01

    The astronautical achievements necessary for guiding Pioneer 10 and 11 and Voyager I and II to the giant planets are reviewed. The spacecraft were equipped with rocket exhausts for both orbital corrections and revolution about their axis. Calculations for the Hohmann transfer orbit are performed, noting that the most efficient trajectory to Jupiter is elliptical, and that the launch dates were strictly circumscribed by the condition that the heliocentric position of Jupiter was necessarily 97 deg longitudinally greater than earth's at the launch. Considerations given to the transition of the dominant gravitational force from the sun to Jupiter are described, together with the calculation procedures. The encounters of each planetary body (and their moons) by each of the probes is detailed. The benefits of gravity assists for gaining velocity are outlined, and the bext favorable window for another grand tour is identified in the 1993-1997 interval

  1. Mass Loss for Highly-Irradiated Giant Planets

    NASA Astrophysics Data System (ADS)

    Hubbard, W. B.; Burrows, A.; Hubeny, I.; Sudarsky, D.; Hattori, M. F.

    2005-08-01

    We present calculations for the surviving mass of highly-irradiated extrasolar giant planets (EGPs) at orbital semimajor axes ranging from 0.023 to 0.057 AU using a generalized scaled theory for mass loss, together with new surface-condition grids for hot EGPs and a consistent treatment of tidal truncation. Available theoretical estimates for the rate of energy-limited hydrogen escape from giant-planet atmospheres range over four orders of magnitude, when one holds planetary mass, composition, and irradiation constant. Yelle (Icarus 170, 167-179, 2004) predicts the lowest escape rate. Baraffe et al. (A&A 419, L13-L16, 2004) predict the highest rate, based on the theory of Lammer et al. (ApJ 598, L121-L124, 2003). Scaling the theory of Watson et al. (Icarus 48, 150-166, 1981) to parameters for a highly-irradiated exoplanet, we find an intermediate escape rate, ˜ 102 higher than Yelle's but ˜ 102 lower than Baraffe's. With the scaled Watson theory and the scaled Yelle theory we find modest mass loss, occurring early in the history of a hot EGP. Particularly for the Yelle theory, the effect of tidal truncation sets the minimum mass limit, well below a Saturn mass for the distances investigated. This contrasts with the Baraffe model, where hot EGPs are claimed to be remnants of much more massive bodies, originally several times Jupiter and still losing substantial mass fractions at present. Supported by NASA Grant NAG5-13775 (PGG) and NASA Grant NNG04GL22G (ATP).

  2. On the Nature and Timing of Giant Planet Migration in the Solar System

    NASA Astrophysics Data System (ADS)

    Agnor, Craig B.

    2016-05-01

    Giant planet migration is a natural outcome of gravitational scattering and planet formation processes (Fernandez & Ip 1984). There is compelling evidence that the solar system's giant planets experienced large-scale migration involving close approaches between planets as well as smooth radial migration via planetesimal scattering. Aspects of giant planet migration have been invoked to explain many features of the outer solar system including the resonant structure of the Kuiper Belt (e.g., Malhotra 1993, Levison et al. 2008), the eccentricities of Jupiter and Saturn (Tsiganis et al. 2005, Morbidelli et al. 2009), the capture of Jupiter's Trojan companions (Morbidelli et al. 2005) and the capture of irregular planetary satellites (e.g., Nesvorny et al. 2007) to name a few. If this migration epoch occurred after the formation of the inner planets, then it may also explain the so-called lunar Late Heavy Bombardment (Gomes et al. 2005). This scenario necessarily requires coeval terrestrial and migrating giant planets. Recent N-body integrations exploring this issue have shown that giant planet migration may excite the terrestrial system via nodal and apsidal secular resonances (e.g., Brasser et al. 2013), may drive the terrestrial planets to crossing orbits (Kaib & Chambers 2016) or alternatively leave the inner solar system in a state closely resembling the observed one (Roig et al. 2016). The factors accounting for the large range of outcomes remain unclear. Using linear secular models and N-body simulations I am identifying and characterising the principal aspects of giant planet migration that excite the terrestrial planets' orbits. I will present these results and discuss how they inform the nature and timing of giant planet migration in the solar system.

  3. Theoretical spectra and atmospheres of extrasolar giant planets

    NASA Astrophysics Data System (ADS)

    Sudarsky, David L.

    This work is a detailed study of extrasolar giant planet (EGP) atmospheres and spectra. Models representative of the full range of systems known today are included, from the extreme close-in EGPs to Jovian-like planets at large orbital radii. Using a self-consistent planar atmosphere code along with the latest atomic and molecular cross sections, cloud models, Mie theory treatment of grain scattering and absorption, and incident stellar fluxes, I produce an extensive set of theoretical EGP atmosphere models and emergent spectra. The emergent spectra of EGPs strongly depend upon their outer atmospheric chemical compositions, which in turn depend upon the run of temperature and pressure with atmospheric depth. Because of qualitative similarities in the compositions and spectra of objects within several broad temperature ranges, EGPs fall naturally into five groups, or composition classes. Such a classification scheme, however preliminary, brings a degree of order to the rich variety of EGP systems known to exist today. Generic models that represent the EGP classes, as well as a set of specific models for a number of important systems that have been detected, are provided. Furthermore, the effects on emergent EGP spectra of varying key parameters such as surface gravity, cloud particle sizes, orbital distance, etc. are modeled. A discussion of current and future ground-based and space- based missions to detect and characterize EGPs in light of theoretical spectral models is included to facilitate an understanding of which systems are most likely to be studied successfully.

  4. Giant Planet Atmospheres: The Illusion of Element Enrichment

    NASA Astrophysics Data System (ADS)

    Owen, Tobias; Bolton, Scott

    2015-04-01

    Contrary to expectation, the mass spectrometer on the Galileo Probe into Jupiter's atmosphere revealed that the abundances of N, C, S, Ar Kr, and Xe relative to hydrogen are all super-solar (Niemann et al. J. Geophys. Res. 103, 22831-22846 (1996), Owen et al. Nature 402, 269-270 (1999)). The most recent values and their uncertainties for both Jovian and solar abundances show an apparent enrichment of 3.5±1.5 X the solar values Subsequently the abundance of carbon (as methane) on Saturn was found by the Cassini IR spectrometer (CIRS) to be 10.9±0.5 X solar (Fletcher et al. Icarus 199, 351-367 (2009)). Attempts to explain these anomalies have focused on delivery of the excess abundances by icy planetesimals. However, new studies of 15N/14N in Saturn, comets and the solar wind support an alternative hypothesis viz., these apparent super-solar abundances are actually the result of a depletion of hydrogen and helium in the matter that made the planets (Guillot and Hueso, Mon. Not. R. Astron. Soc., 367, L47-L51 (2006)). This depletion is the result of photoevaporation and viscous spreading of the solar nebula. There is no requirement for augmentation of specific element abundances; the accretion-collapse model for giant planet formation remains valid.

  5. Exploring extrasolar worlds: from gas giants to terrestrial habitable planets.

    PubMed

    Tinetti, Giovanna; Griffith, Caitlin A; Swain, Mark R; Deroo, Pieter; Beaulieu, Jean Philippe; Vasisht, Gautam; Kipping, David; Waldmann, Ingo; Tennyson, Jonathan; Barber, Robert J; Bouwman, Jeroen; Allard, Nicole; Brown, Linda R

    2010-01-01

    Almost 500 extrasolar planets have been found since the discovery of 51 Peg b by Mayor and Queloz in 1995. The traditional field of planetology has thus expanded its frontiers to include planetary environments not represented in our Solar System. We expect that in the next five years space missions (Corot, Kepler and GAIA) or ground-based detection techniques will both increase exponentially the number of new planets discovered and lower the present limit of a approximately 1.9 Earth-mass object [e.g. Mayor et al., Astron. Astrophys., 2009, 507, 487]. While the search for an Earth-twin orbiting a Sun-twin has been one of the major goals pursued by the exoplanet community in the past years, the possibility of sounding the atmospheric composition and structure of an increasing sample of exoplanets with current telescopes has opened new opportunities, unthinkable just a few years ago. As a result, it is possible now not only to determine the orbital characteristics of the new bodies, but moreover to study the exotic environments that lie tens of parsecs away from us. The analysis of the starlight not intercepted by the thin atmospheric limb of its planetary companion (transit spectroscopy), or of the light emitted/reflected by the exoplanet itself, will guide our understanding of the atmospheres and the surfaces of these extrasolar worlds in the next few years. Preliminary results obtained by interpreting current atmospheric observations of transiting gas giants and Neptunes are presented. While the full characterisation of an Earth-twin might requires a technological leap, our understanding of large terrestrial planets (so called super-Earths) orbiting bright, later-type stars is within reach by current space and ground telescopes.

  6. Magnetic coupling in the disks around young gas giant planets

    SciTech Connect

    Turner, N. J.; Lee, Man Hoi; Sano, T. E-mail: mhlee@hku.hk

    2014-03-01

    We examine the conditions under which the disks of gas and dust orbiting young gas giant planets are sufficiently conducting to experience turbulence driven by the magneto-rotational instability. By modeling the ionization and conductivity in the disk around proto-Jupiter, we find that turbulence is possible if the X-rays emitted near the Sun reach the planet's vicinity and either (1) the gas surface densities are in the range of the minimum-mass models constructed by augmenting Jupiter's satellites to solar composition, while dust is depleted from the disk atmosphere, or (2) the surface densities are much less, and in the range of gas-starved models fed with material from the solar nebula, but not so low that ambipolar diffusion decouples the neutral gas from the plasma. The results lend support to both minimum-mass and gas-starved models of the protojovian disk. (1) The dusty minimum-mass models have internal conductivities low enough to prevent angular momentum transfer by magnetic forces, as required for the material to remain in place while the satellites form. (2) The gas-starved models have magnetically active surface layers and a decoupled interior 'dead zone'. Similar active layers in the solar nebula yield accretion stresses in the range assumed in constructing the circumjovian gas-starved models. Our results also point to aspects of both classes of models that can be further developed. Non-turbulent minimum-mass models will lose dust from their atmospheres by settling, enabling gas to accrete through a thin surface layer. For the gas-starved models it is crucial to learn whether enough stellar X-ray and ultraviolet photons reach the circumjovian disk. Additionally, the stress-to-pressure ratio ought to increase with distance from the planet, likely leading to episodic accretion outbursts.

  7. Magnetic Coupling in the Disks around Young Gas Giant Planets

    NASA Astrophysics Data System (ADS)

    Turner, N. J.; Lee, Man Hoi; Sano, T.

    2014-03-01

    We examine the conditions under which the disks of gas and dust orbiting young gas giant planets are sufficiently conducting to experience turbulence driven by the magneto-rotational instability. By modeling the ionization and conductivity in the disk around proto-Jupiter, we find that turbulence is possible if the X-rays emitted near the Sun reach the planet's vicinity and either (1) the gas surface densities are in the range of the minimum-mass models constructed by augmenting Jupiter's satellites to solar composition, while dust is depleted from the disk atmosphere, or (2) the surface densities are much less, and in the range of gas-starved models fed with material from the solar nebula, but not so low that ambipolar diffusion decouples the neutral gas from the plasma. The results lend support to both minimum-mass and gas-starved models of the protojovian disk. (1) The dusty minimum-mass models have internal conductivities low enough to prevent angular momentum transfer by magnetic forces, as required for the material to remain in place while the satellites form. (2) The gas-starved models have magnetically active surface layers and a decoupled interior "dead zone." Similar active layers in the solar nebula yield accretion stresses in the range assumed in constructing the circumjovian gas-starved models. Our results also point to aspects of both classes of models that can be further developed. Non-turbulent minimum-mass models will lose dust from their atmospheres by settling, enabling gas to accrete through a thin surface layer. For the gas-starved models it is crucial to learn whether enough stellar X-ray and ultraviolet photons reach the circumjovian disk. Additionally, the stress-to-pressure ratio ought to increase with distance from the planet, likely leading to episodic accretion outbursts.

  8. Exploring extrasolar worlds: from gas giants to terrestrial habitable planets.

    PubMed

    Tinetti, Giovanna; Griffith, Caitlin A; Swain, Mark R; Deroo, Pieter; Beaulieu, Jean Philippe; Vasisht, Gautam; Kipping, David; Waldmann, Ingo; Tennyson, Jonathan; Barber, Robert J; Bouwman, Jeroen; Allard, Nicole; Brown, Linda R

    2010-01-01

    Almost 500 extrasolar planets have been found since the discovery of 51 Peg b by Mayor and Queloz in 1995. The traditional field of planetology has thus expanded its frontiers to include planetary environments not represented in our Solar System. We expect that in the next five years space missions (Corot, Kepler and GAIA) or ground-based detection techniques will both increase exponentially the number of new planets discovered and lower the present limit of a approximately 1.9 Earth-mass object [e.g. Mayor et al., Astron. Astrophys., 2009, 507, 487]. While the search for an Earth-twin orbiting a Sun-twin has been one of the major goals pursued by the exoplanet community in the past years, the possibility of sounding the atmospheric composition and structure of an increasing sample of exoplanets with current telescopes has opened new opportunities, unthinkable just a few years ago. As a result, it is possible now not only to determine the orbital characteristics of the new bodies, but moreover to study the exotic environments that lie tens of parsecs away from us. The analysis of the starlight not intercepted by the thin atmospheric limb of its planetary companion (transit spectroscopy), or of the light emitted/reflected by the exoplanet itself, will guide our understanding of the atmospheres and the surfaces of these extrasolar worlds in the next few years. Preliminary results obtained by interpreting current atmospheric observations of transiting gas giants and Neptunes are presented. While the full characterisation of an Earth-twin might requires a technological leap, our understanding of large terrestrial planets (so called super-Earths) orbiting bright, later-type stars is within reach by current space and ground telescopes. PMID:21302557

  9. PLANET ENGULFMENT BY {approx}1.5-3 M{sub sun} RED GIANTS

    SciTech Connect

    Kunitomo, M.; Ikoma, M.; Sato, B.; Ida, S.; Katsuta, Y.

    2011-08-20

    Recent radial-velocity surveys for GK clump giants have revealed that planets also exist around {approx}1.5-3 M{sub sun} stars. However, no planets have been found inside 0.6 AU around clump giants, in contrast to solar-type main-sequence stars, many of which harbor short-period planets such as hot Jupiters. In this study, we examine the possibility that planets were engulfed by host stars evolving on the red-giant branch (RGB). We integrate the orbital evolution of planets in the RGB and helium-burning phases of host stars, including the effects of stellar tide and stellar mass loss. Then we derive the critical semimajor axis (or the survival limit) inside which planets are eventually engulfed by their host stars after tidal decay of their orbits. Specifically, we investigate the impact of stellar mass and other stellar parameters on the survival limit in more detail than previous studies. In addition, we make detailed comparisons with measured semimajor axes of planets detected so far, which no previous study has done. We find that the critical semimajor axis is quite sensitive to stellar mass in the range between 1.7 and 2.1 M{sub sun}, which suggests a need for careful comparison between theoretical and observational limits of the existence of planets. Our comparison demonstrates that all planets orbiting GK clump giants that have been detected are beyond the survival limit, which is consistent with the planet-engulfment hypothesis. However, on the high-mass side (>2.1M{sub sun}), the detected planets are orbiting significantly far from the survival limit, which suggests that engulfment by host stars may not be the main reason for the observed lack of short-period giant planets. To confirm our conclusion, the detection of more planets around clump giants, especially with masses {approx}> 2.5M{sub sun}, is required.

  10. Extrasolar Giant Planet in Earth-like Orbit

    NASA Astrophysics Data System (ADS)

    1999-07-01

    companion . iota Hor b has an orbital period of 320 days. From this period, the known mass of the central star (1.03 solar masses) and the amplitude of the velocity changes, a mass of at least 2.26 times that of planet Jupiter is deduced for the planet. It revolves around the host star in a somewhat elongated orbit (the eccentricity is 0.16). If it were located in our own solar system, this orbit would stretch from just outside the orbit of Venus (at 117 million km or 0.78 Astronomical Units from the Sun) to just outside the orbit of the Earth (the point farthest from the Sun, at 162 million km or 1.08 Astronomical Units) The new giant planet is thus moving in an orbit not unlike that of the Earth. In fact, of all the planets discovered so far, the orbit of iota Hor b is the most Earth-like. Also, with a spectral type of G0 V , its host star is quite similar to the Sun (G2 V). iota Hor b is, however, at least 720 times more massive than the Earth and it is probably more similar to planet Jupiter in our own solar system. While the radial velocity technique described above only determines a minimum value for the planet's mass, an analysis of the velocity with which the star turns around its own axis suggests that the true mass of iota Hor b is unlikely to be much higher. A difficult case Natural phenomena with periods near one solar year always present a particular challenge to astronomers. This is one of the reasons why it has been necessary to observe the iota Hor system for such a long time to be absolutely sure about the present result. First, special care must be taken to verify that the radial velocity variations found in the data are not an artefact of the Earth's movement around the Sun. In any case, the effect of this movement on the measurements must be accurately accounted for; it reaches about ± 30 km/sec over one year, i.e. much larger than the effect of the new planet. In the present case of iota Hor , this was thoroughly tested and any residual influence of

  11. Characterizing Young Giant Planets with the Gemini Planet Imager: An Iterative Approach to Planet Characterization

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2015-01-01

    After discovery, the first task of exoplanet science is characterization. However experience has shown that the limited spectral range and resolution of most directly imaged exoplanet data requires an iterative approach to spectral modeling. Simple, brown dwarf-like models, must first be tested to ascertain if they are both adequate to reproduce the available data and consistent with additional constraints, including the age of the system and available limits on the planet's mass and luminosity, if any. When agreement is lacking, progressively more complex solutions must be considered, including non-solar composition, partial cloudiness, and disequilibrium chemistry. Such additional complexity must be balanced against an understanding of the limitations of the atmospheric models themselves. For example while great strides have been made in improving the opacities of important molecules, particularly NH3 and CH4, at high temperatures, much more work is needed to understand the opacity of atomic Na and K. The highly pressure broadened fundamental band of Na and K in the optical stretches into the near-infrared, strongly influencing the spectral shape of Y and J spectral bands. Discerning gravity and atmospheric composition is difficult, if not impossible, without both good atomic opacities as well as an excellent understanding of the relevant atmospheric chemistry. I will present examples of the iterative process of directly imaged exoplanet characterization as applied to both known and potentially newly discovered exoplanets with a focus on constraints provided by GPI spectra. If a new GPI planet is lacking, as a case study I will discuss HR 8799 c and d will explain why some solutions, such as spatially inhomogeneous cloudiness, introduce their own additional layers of complexity. If spectra of new planets from GPI are available I will explain the modeling process in the context of understanding these new worlds.

  12. THE CALIFORNIA PLANET SURVEY IV: A PLANET ORBITING THE GIANT STAR HD 145934 AND UPDATES TO SEVEN SYSTEMS WITH LONG-PERIOD PLANETS

    SciTech Connect

    Katherina Feng, Y.; Wright, Jason T.; Nelson, Benjamin; Wang, Sharon X.; Ford, Eric B.; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.

    2015-02-10

    We present an update to seven stars with long-period planets or planetary candidates using new and archival radial velocities from Keck-HIRES and literature velocities from other telescopes. Our updated analysis better constrains orbital parameters for these planets, four of which are known multi-planet systems. HD 24040 b and HD 183263 c are super-Jupiters with circular orbits and periods longer than 8 yr. We present a previously unseen linear trend in the residuals of HD 66428 indicative of an additional planetary companion. We confirm that GJ 849 is a multi-planet system and find a good orbital solution for the c component: it is a 1 M {sub Jup} planet in a 15 yr orbit (the longest known for a planet orbiting an M dwarf). We update the HD 74156 double-planet system. We also announce the detection of HD 145934 b, a 2 M {sub Jup} planet in a 7.5 yr orbit around a giant star. Two of our stars, HD 187123 and HD 217107, at present host the only known examples of systems comprising a hot Jupiter and a planet with a well constrained period greater than 5 yr, and with no evidence of giant planets in between. Our enlargement and improvement of long-period planet parameters will aid future analysis of origins, diversity, and evolution of planetary systems.

  13. ATMOSPHERIC DYNAMICS OF BROWN DWARFS AND DIRECTLY IMAGED GIANT PLANETS

    SciTech Connect

    Showman, Adam P.; Kaspi, Yohai

    2013-10-20

    A variety of observations provide evidence for vigorous motion in the atmospheres of brown dwarfs and directly imaged giant planets. Motivated by these observations, we examine the dynamical regime of the circulation in the atmospheres and interiors of these objects. Brown dwarfs rotate rapidly, and for plausible wind speeds, the flow at large scales will be rotationally dominated. We present three-dimensional, global, numerical simulations of convection in the interior, which demonstrate that at large scales, the convection aligns in the direction parallel to the rotation axis. Convection occurs more efficiently at high latitudes than low latitudes, leading to systematic equator-to-pole temperature differences that may reach ∼1 K near the top of the convection zone. The interaction of convection with the overlying, stably stratified atmosphere will generate a wealth of atmospheric waves, and we argue that, as in the stratospheres of planets in the solar system, the interaction of these waves with the mean flow will cause a significant atmospheric circulation at regional to global scales. At large scales, this should consist of stratified turbulence (possibly organizing into coherent structures such as vortices and jets) and an accompanying overturning circulation. We present an approximate analytic theory of this circulation, which predicts characteristic horizontal temperature variations of several to ∼50 K, horizontal wind speeds of ∼10-300 m s{sup –1}, and vertical velocities that advect air over a scale height in ∼10{sup 5}-10{sup 6} s. This vertical mixing may help to explain the chemical disequilibrium observed on some brown dwarfs. Moreover, the implied large-scale organization of temperature perturbations and vertical velocities suggests that near the L/T transition, patchy clouds can form near the photosphere, helping to explain recent observations of brown-dwarf variability in the near-IR.

  14. Giant planets and their satellites: What are the relationships between their properties and how they formed

    NASA Technical Reports Server (NTRS)

    Stevenson, David J.

    1991-01-01

    The following subject areas are covered: (1) the mass distribution; (2) interior models; (3) atmospheric compositions and their implications; (4) heat flows and their implications; (5) satellite systems; (6) temperatures in the solar nebula; and (7) giant planet formation.

  15. Accessing High Pressure States Relevant to Core Conditions in the Giant Planets

    SciTech Connect

    Remington, B A; Cavallo, R M; Edwards, M J; Ho, D D; Lorenz, K T; Lorenzana, H E; Lasinski, B F; McNaney, J M; Pollaine, S M; Smith, R F

    2004-04-15

    We have designed an experimental technique to use on the National Ignition Facility (NIF) laser to achieve very high pressure (P{sub max} > 10 Mbar = 1000 GPa), dense states of matter at moderate temperatures (kT < 0.5 eV = 6000 K), relevant to the core conditions of the giant planets. A discussion of the conditions in the interiors of the giant planets is given, and an experimental design that can approach those conditions is described.

  16. ON THE SURVIVABILITY AND METAMORPHISM OF TIDALLY DISRUPTED GIANT PLANETS: THE ROLE OF DENSE CORES

    SciTech Connect

    Liu, Shang-Fei; Lin, Douglas N. C.; Guillochon, James; Ramirez-Ruiz, Enrico

    2013-01-01

    A large population of planetary candidates in short-period orbits have been found recently through transit searches, mostly with the Kepler mission. Radial velocity surveys have also revealed several Jupiter-mass planets with highly eccentric orbits. Measurements of the Rossiter-McLaughlin effect indicate that the orbital angular momentum vector of some planets is inclined relative to the spin axis of their host stars. This diversity could be induced by post-formation dynamical processes such as planet-planet scattering, the Kozai effect, or secular chaos which brings planets to the vicinity of their host stars. In this work, we propose a novel mechanism to form close-in super-Earths and Neptune-like planets through the tidal disruption of gas giant planets as a consequence of these dynamical processes. We model the core-envelope structure of gas giant planets with composite polytropes which characterize the distinct chemical composition of the core and envelope. Using three-dimensional hydrodynamical simulations of close encounters between Jupiter-like planets and their host stars, we find that the presence of a core with a mass more than 10 times that of the Earth can significantly increase the fraction of envelope which remains bound to it. After the encounter, planets with cores are more likely to be retained by their host stars in contrast with previous studies which suggested that coreless planets are often ejected. As a substantial fraction of their gaseous envelopes is preferentially lost while the dense incompressible cores retain most of their original mass, the resulting metallicity of the surviving planets is increased. Our results suggest that some gas giant planets can be effectively transformed into either super-Earths or Neptune-like planets after multiple close stellar passages. Finally, we analyze the orbits and structure of known planets and Kepler candidates and find that our model is capable of producing some of the shortest-period objects.

  17. Planetary Formation: From the Earth and Moon to Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)

    1999-01-01

    An overview of current theories of star and planet formation is presented. These models are based upon observations of the Solar System and of young stars and their environments. They predict that rocky planets should form around most single stars, although it is possible that in some cases-such planets are lost to orbital decay within the protoplanetary disk. The frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth like terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Specific issues to be discussed include: (1) how large a solid core is needed to initiate rapid accumulation of gas? (2) can giant planets form very close to stars? (3) could a giant impact leading to lunar formation have occurred approx. 100 million years after the condensation of the oldest meteorites?

  18. Planetary Formation: From the Earth and Moon to Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack; DeVincenzi, Donald (Technical Monitor)

    1999-01-01

    An overview of current theories of star and planet formation is presented. These models are based upon observations of the Solar System and of young stars and their environments. They predict that rocky planets should form around most single stars, although it is possible that in some cases such planets are lost to orbital decay within the protoplanetary disk. The frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth like terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Specific issues to be discussed include: (1) how large a solid core is needed to initiate rapid accumulation of gas? (2) can giant planets form very close to stars? (3) could a giant impact leading to lunar formation have occurred approximately 100 million years after the condensation of the oldest meteorites?

  19. Statistics of Long Period Gas Giant Planets in Known Planetary Systems

    NASA Astrophysics Data System (ADS)

    Bryan, Marta L.; Knutson, Heather A.; Howard, Andrew W.; Ngo, Henry; Batygin, Konstantin; Crepp, Justin R.; Fulton, B. J.; Hinkley, Sasha; Isaacson, Howard; Johnson, John A.; Marcy, Geoffry W.; Wright, Jason T.

    2016-04-01

    We conducted a Doppler survey at Keck combined with NIRC2 K-band adaptive optics (AO) imaging to search for massive, long-period companions to 123 known exoplanet systems with one or two planets detected using the radial velocity (RV) method. Our survey is sensitive to Jupiter-mass planets out to 20 au for a majority of stars in our sample, and we report the discovery of eight new long-period planets, in addition to 20 systems with statistically significant RV trends that indicate the presence of an outer companion beyond 5 au. We combine our RV observations with AO imaging to determine the range of allowed masses and orbital separations for these companions, and account for variations in our sensitivity to companions among stars in our sample. We estimate the total occurrence rate of companions in our sample to be 52 ± 5% over the range 1–20 MJup and 5–20 au. Our data also suggest a declining frequency for gas giant planets in these systems beyond 3–10 au, in contrast to earlier studies that found a rising frequency for giant planets in the range 0.01–3 au. This suggests either that the frequency of gas giant planets peaks between 3 and 10 au, or that outer companions in these systems have a different semi-major axis distribution than the overall population of gas giant planets. Our results also suggest that hot gas giants may be more likely to have an outer companion than cold gas giants. We find that planets with an outer companion have higher average eccentricities than their single counterparts, suggesting that dynamical interactions between planets may play an important role in these systems.

  20. M Dwarf Metallicities and Giant Planet Occurrence: Ironing Out Uncertainties and Systematics

    NASA Astrophysics Data System (ADS)

    Gaidos, Eric; Mann, Andrew W.

    2014-08-01

    Comparisons between the planet populations around solar-type stars and those orbiting M dwarfs shed light on the possible dependence of planet formation and evolution on stellar mass. However, such analyses must control for other factors, i.e., metallicity, a stellar parameter that strongly influences the occurrence of gas giant planets. We obtained infrared spectra of 121 M dwarfs stars monitored by the California Planet Search and determined metallicities with an accuracy of 0.08 dex. The mean and standard deviation of the sample are -0.05 and 0.20 dex, respectively. We parameterized the metallicity dependence of the occurrence of giant planets on orbits with a period less than two years around solar-type stars and applied this to our M dwarf sample to estimate the expected number of giant planets. The number of detected planets (3) is lower than the predicted number (6.4), but the difference is not very significant (12% probability of finding as many or fewer planets). The three M dwarf planet hosts are not especially metal rich and the most likely value of the power-law index relating planet occurrence to metallicity is 1.06 dex per dex for M dwarfs compared to 1.80 for solar-type stars; this difference, however, is comparable to uncertainties. Giant planet occurrence around both types of stars allows, but does not necessarily require, a mass dependence of ~1 dex per dex. The actual planet-mass-metallicity relation may be complex, and elucidating it will require larger surveys like those to be conducted by ground-based infrared spectrographs and the Gaia space astrometry mission.

  1. M dwarf metallicities and giant planet occurrence: Ironing out uncertainties and systematics

    SciTech Connect

    Gaidos, Eric; Mann, Andrew W.

    2014-08-10

    Comparisons between the planet populations around solar-type stars and those orbiting M dwarfs shed light on the possible dependence of planet formation and evolution on stellar mass. However, such analyses must control for other factors, i.e., metallicity, a stellar parameter that strongly influences the occurrence of gas giant planets. We obtained infrared spectra of 121 M dwarfs stars monitored by the California Planet Search and determined metallicities with an accuracy of 0.08 dex. The mean and standard deviation of the sample are –0.05 and 0.20 dex, respectively. We parameterized the metallicity dependence of the occurrence of giant planets on orbits with a period less than two years around solar-type stars and applied this to our M dwarf sample to estimate the expected number of giant planets. The number of detected planets (3) is lower than the predicted number (6.4), but the difference is not very significant (12% probability of finding as many or fewer planets). The three M dwarf planet hosts are not especially metal rich and the most likely value of the power-law index relating planet occurrence to metallicity is 1.06 dex per dex for M dwarfs compared to 1.80 for solar-type stars; this difference, however, is comparable to uncertainties. Giant planet occurrence around both types of stars allows, but does not necessarily require, a mass dependence of ∼1 dex per dex. The actual planet-mass-metallicity relation may be complex, and elucidating it will require larger surveys like those to be conducted by ground-based infrared spectrographs and the Gaia space astrometry mission.

  2. Formation of Close-in Terrestrial Planets by Giant Impacts: The Basic Scaling Laws

    NASA Astrophysics Data System (ADS)

    Kokubo, Eiichiro

    2015-12-01

    The recent exoplanet surveys have shown that small close-in planets are more common than hot Jupiters. Most of them are considered as terrestrial (rocky) planets. Thus it becomes increasingly important to generally understand the formation of terrestrial planets. In the standard scenario of terrestrial planet formation, the final stage is the giant impact stage after the dispersal of a gas disk where protoplanets or planetary embryos collide with one another to complete planets. In the present paper, we investigate the in-situ formation of close-in terrestrial planets including super-Earths by giant impacts using N-body simulations. The goal of this project is to obtain the basic scaling laws of close-in terrestrial planet formation as a function of properties of protoplanet systems. We systematically change the system parameters of initial protoplanet systems and investigate their effects on the final planets. We find that in general non-resonant dynamically cold compact systems are formed. The orbits of planets are less eccentric and inclined and the orbital separations of adjacent planets are smaller, compared with those formed in the outer disk. The masses of all planets are almost comparable. These properties are natural outcomes of giant impacts in the inner disk. In the inner disk the ratio of the physical radius to the Hill radius is large, in other words, gravitational scattering is relatively less effective compared with that in the outer disk. Thus protoplanets are less mobile and accretion proceeds relatively locally, which leads to formation of dynamically cold compact systems. The typical mass of the largest planet increases almost linearly with the total mass of protoplanets, while the number of planets per radial width decreases. On average the system angular momentum deficit increases with the total system mass, while the mean orbital separation of adjacent planets decreases.

  3. Energy Budgets of the Giant Planets and Titan

    NASA Technical Reports Server (NTRS)

    Liming, Li; Smith, Mark A.; Conrath, Barney J.; Conrath, Peter J.; Simon-Miller, Amy A.; Baines, Kevin H.; West, Robert A.; Achterberg, Richard K.; Orton, Glenn S.; Santiago, Perez-Hoyos; Trammel, Harold J.; Banfield, Don; Jiang, Xun; Nixon, Conor A.; Bjoraker, Gordon L.; Mamoutkine, Andrei A.; Segura, Marcia E.; Gorius, Nicolas; Flasar, F. Michael; Flacchione, Gianrico; Fry, Patrick M.; Momary, Thomas W.; Ingersoll, Andrew P.; Porco, Carolyn C.; Vasavada, Ashwin R.

    2012-01-01

    As a fundamental property, the energy budget affects many aspeCts of planets and their moons, such as thermal structure, meteorology, and evolution. We use the observations from two Cassini spectrometers (i.e., CIRS and VIMS) to explore one important component of the energy budget the total emitted power of Jupiter, Saturn, and Titan (Li et al., 2010, 2011, 2012). Key results are: (1) The Cassini observations precisely measure the global-average emitted power of three bodies: 14.l0+/-0.03 Wm(exp -2), 4.952+/-0.035 Wm(exp -2), and 2.834+/-0.012 Wm(exp -2) for Jupiter, Saturn, and Titan, respectively. (2) The meridional distribution of emitted power displays a significant asymmetry between the northern and southern hemispheres on Jupiter and Saturn. On Titan, the meridional distribution of emitted power is basically symmetric around the equator. (3) Comparing with the Voyager measurements, the new Cassini observations reveal a significant temporal variation of emitted power on both Jupiter and Saturn: i) The asymmetry between the two hemisphere shown in the Cassini epoch (2000-2010) is not present in the Voyager epoch (1979-1980); and ii) From the Voyager epoch to the Cassini epoch, the global-average emitted power appeared to increase by approx 3.8% for Jupiter and approx 6.4% for Saturn. (4) Together with previous measurements of the absorbed solar power on Titan, the new Cassini measurements of emitted power provide the first observational evidence of the global energy balance on Titan. The uncertainty in the previous measurements of absorbed solar energy places an upper limit on its energy imbalance of 6.0% on Titan. The exploration of emitted power is the first part of a series of studies examining the temporal variability of the energy budget on the giant planets and Titan. Currently, We are measuring the absorbed solar energy in order to determine new constraints on the energy budgets of Jupiter, Saturn, and Titan.

  4. Four new planets around giant stars and the mass-metallicity correlation of planet-hosting stars

    NASA Astrophysics Data System (ADS)

    Jones, M. I.; Jenkins, J. S.; Brahm, R.; Wittenmyer, R. A.; Olivares E., F.; Melo, C. H. F.; Rojo, P.; Jordán, A.; Drass, H.; Butler, R. P.; Wang, L.

    2016-05-01

    Context. Exoplanet searches have revealed interesting correlations between the stellar properties and the occurrence rate of planets. In particular, different independent surveys have demonstrated that giant planets are preferentially found around metal-rich stars and that their fraction increases with the stellar mass. Aims: During the past six years we have conducted a radial velocity follow-up program of 166 giant stars to detect substellar companions and to characterize their orbital properties. Using this information, we aim to study the role of the stellar evolution in the orbital parameters of the companions and to unveil possible correlations between the stellar properties and the occurrence rate of giant planets. Methods: We took multi-epoch spectra using FEROS and CHIRON for all of our targets, from which we computed precision radial velocities and derived atmospheric and physical parameters. Additionally, velocities computed from UCLES spectra are presented here. By studying the periodic radial velocity signals, we detected the presence of several substellar companions. Results: We present four new planetary systems around the giant stars HIP 8541, HIP 74890, HIP 84056, and HIP 95124. Additionally, we study the correlation between the occurrence rate of giant planets with the stellar mass and metallicity of our targets. We find that giant planets are more frequent around metal-rich stars, reaching a peak in the detection of f = 16.7+15.5-5.9% around stars with [Fe/H] ~ 0.35 dex. Similarly, we observe a positive correlation of the planet occurrence rate with the stellar mass, between M⋆ ~ 1.0 and 2.1 M⊙, with a maximum of f = 13.0+10.1-4.2% at M⋆ = 2.1 M⊙. Conclusions: We conclude that giant planets are preferentially formed around metal-rich stars. In addition, we conclude that they are more efficiently formed around more massive stars, in the stellar mass range of ~1.0-2.1 M⊙. These observational results confirm previous findings for solar

  5. Very high-density planets: a possible remnant of gas giants.

    PubMed

    Mocquet, A; Grasset, O; Sotin, C

    2014-04-28

    Data extracted from the Extrasolar Planets Encyclopaedia (see http://exoplanet.eu) show the existence of planets that are more massive than iron cores that would have the same size. After meticulous verification of the data, we conclude that the mass of the smallest of these planets is actually not known. However, the three largest planets, Kepler-52b, Kepler-52c and Kepler-57b, which are between 30 and 100 times the mass of the Earth, have indeed density larger than an iron planet of the same size. This observation triggers this study that investigates under which conditions these planets could represent the naked cores of gas giants that would have lost their atmospheres during their migration towards the star. This study shows that for moderate viscosity values (10(25) Pa s or lower), large values of escape rate and associated unloading stress rate during the atmospheric loss process lead to the explosion of extremely massive planets. However, for moderate escape rate, the bulk viscosity and finite-strain incompressibility of the cores of giant planets can be large enough to retain a very high density during geological time scales. This would make those a new kind of planet, which would help in understanding the interior structure of the gas giants. However, this new family of exoplanets adds some degeneracy for characterizing terrestrial exoplanets. PMID:24664925

  6. Very high-density planets: a possible remnant of gas giants.

    PubMed

    Mocquet, A; Grasset, O; Sotin, C

    2014-04-28

    Data extracted from the Extrasolar Planets Encyclopaedia (see http://exoplanet.eu) show the existence of planets that are more massive than iron cores that would have the same size. After meticulous verification of the data, we conclude that the mass of the smallest of these planets is actually not known. However, the three largest planets, Kepler-52b, Kepler-52c and Kepler-57b, which are between 30 and 100 times the mass of the Earth, have indeed density larger than an iron planet of the same size. This observation triggers this study that investigates under which conditions these planets could represent the naked cores of gas giants that would have lost their atmospheres during their migration towards the star. This study shows that for moderate viscosity values (10(25) Pa s or lower), large values of escape rate and associated unloading stress rate during the atmospheric loss process lead to the explosion of extremely massive planets. However, for moderate escape rate, the bulk viscosity and finite-strain incompressibility of the cores of giant planets can be large enough to retain a very high density during geological time scales. This would make those a new kind of planet, which would help in understanding the interior structure of the gas giants. However, this new family of exoplanets adds some degeneracy for characterizing terrestrial exoplanets.

  7. Giant impacts during planet formation: Parallel tree code simulations using smooth particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Cohen, Randi L.

    There is both theoretical and observational evidence that giant planets collided with objects ≥ Mearth during their evolution. These impacts may play a key role in giant planet formation. This paper describes impacts of a ˜ Earth-mass object onto a suite of proto-giant-planets, as simulated using an SPH parallel tree code. We run 6 simulations, varying the impact angle and evolutionary stage of the proto-Jupiter. We find that it is possible for an impactor to free some mass from the core of the proto-planet it impacts through direct collision, as well as to make physical contact with the core yet escape partially, or even completely, intact. None of the 6 cases we consider produced a solid disk or resulted in a net decrease in the core mass of the pinto-planet (since the mass decrease due to disruption was outweighed by the increase due to the addition of the impactor's mass to the core). However, we suggest parameters which may have these effects, and thus decrease core mass and formation time in protoplanetary models and/or create satellite systems. We find that giant impacts can remove significant envelope mass from forming giant planets, leaving only 2 MEarth of gas, similar to Uranus and Neptune. They can also create compositional inhomogeneities in planetary cores, which creates differences in planetary thermal emission characteristics.

  8. A compact system of small planets around a former red-giant star.

    PubMed

    Charpinet, S; Fontaine, G; Brassard, P; Green, E M; Van Grootel, V; Randall, S K; Silvotti, R; Baran, A S; Ostensen, R H; Kawaler, S D; Telting, J H

    2011-12-22

    Planets that orbit their parent star at less than about one astronomical unit (1 AU is the Earth-Sun distance) are expected to be engulfed when the star becomes a red giant. Previous observations have revealed the existence of post-red-giant host stars with giant planets orbiting as close as 0.116 AU or with brown dwarf companions in tight orbits, showing that these bodies can survive engulfment. What has remained unclear is whether planets can be dragged deeper into the red-giant envelope without being disrupted and whether the evolution of the parent star itself could be affected. Here we report the presence of two nearly Earth-sized bodies orbiting the post-red-giant, hot B subdwarf star KIC 05807616 at distances of 0.0060 and 0.0076 AU, with orbital periods of 5.7625 and 8.2293 hours, respectively. These bodies probably survived deep immersion in the former red-giant envelope. They may be the dense cores of evaporated giant planets that were transported closer to the star during the engulfment and triggered the mass loss necessary for the formation of the hot B subdwarf, which might also explain how some stars of this type did not form in binary systems. PMID:22193103

  9. A compact system of small planets around a former red-giant star.

    PubMed

    Charpinet, S; Fontaine, G; Brassard, P; Green, E M; Van Grootel, V; Randall, S K; Silvotti, R; Baran, A S; Ostensen, R H; Kawaler, S D; Telting, J H

    2011-12-21

    Planets that orbit their parent star at less than about one astronomical unit (1 AU is the Earth-Sun distance) are expected to be engulfed when the star becomes a red giant. Previous observations have revealed the existence of post-red-giant host stars with giant planets orbiting as close as 0.116 AU or with brown dwarf companions in tight orbits, showing that these bodies can survive engulfment. What has remained unclear is whether planets can be dragged deeper into the red-giant envelope without being disrupted and whether the evolution of the parent star itself could be affected. Here we report the presence of two nearly Earth-sized bodies orbiting the post-red-giant, hot B subdwarf star KIC 05807616 at distances of 0.0060 and 0.0076 AU, with orbital periods of 5.7625 and 8.2293 hours, respectively. These bodies probably survived deep immersion in the former red-giant envelope. They may be the dense cores of evaporated giant planets that were transported closer to the star during the engulfment and triggered the mass loss necessary for the formation of the hot B subdwarf, which might also explain how some stars of this type did not form in binary systems.

  10. Rossby solitary vortices, on giant planets and in the laboratory.

    PubMed

    Nezlin, Mikhail V.

    1994-06-01

    This is a review of laboratory experiments with a layer of shallow water having a free surface and rotating together with a vessel of parabolic form. Such a (rather original) setup has allowed one to create Rossby solitary vortex for the first time. The latter is an anticyclonic Rossby vortex not subjected to dispersive spread owing to its compensation by the nonlinearity of KdV type. By its structural, collisional, and other properties, including clear-cut cyclonic-anticyclonic asymmetry, it may be considered as a physical prototype of the large-scale long-lived anticyclonic Rossby vortices like the Great Red Spot of Jupiter or the Great Dark Spot of Neptune (this remarkable vortex was discovered by the spacecraft Voyager-2 during its farewell to the Solar System) and other vortices dominating in the atmospheres of giant planets and created by the unstable zonal flows. It has been shown that the vortex under study is a long-lived entity provided it satisfies "antitwisting condition," i.e., it has rather large amplitude (at which it rotates more quickly than it propagates and thereby carries the trapped fluid). In this case, it is not subjected to the "twisting" deformation and may be ascribed by the generalized Charney-Obukhov equation for Rossby vortices on shallow water with a free surface. The results of creating the vortex under consideration by the different methods have been compared with the results obtained by other authors in the experiments on shear-flow generation of Rossby vortices. PMID:12780099

  11. Hot super-Earths and giant planet cores from different migration histories

    NASA Astrophysics Data System (ADS)

    Cossou, Christophe; Raymond, Sean N.; Hersant, Franck; Pierens, Arnaud

    2014-09-01

    Planetary embryos embedded in gaseous protoplanetary disks undergo Type I orbital migration. Migration can be inward or outward depending on the local disk properties but, in general, only planets more massive than several M⊕ can migrate outward. Here we propose that an embryo's migration history determines whether it becomes a hot super-Earth or the core of a giant planet. Systems of hot super-Earths (or mini-Neptunes) form when embryos migrate inward and pile up at the inner edge of the disk. Giant planet cores form when inward-migrating embryos become massive enough to switch direction and migrate outward. We present simulations of this process using a modified N-body code, starting from a swarm of planetary embryos. Systems of hot super-Earths form in resonant chains with the innermost planet at or interior to the disk inner edge. Resonant chains are disrupted by late dynamical instabilities triggered by the dispersal of the gaseous disk. Giant planet cores migrate outward toward zero-torque zones, which move inward and eventually disappear as the disk disperses. Giant planet cores migrate inward with these zones and are stranded at ~1-5 AU. Our model reproduces several properties of the observed extra-solar planet populations. The frequency of giant planet cores increases strongly when the mass in solids is increased, consistent with the observed giant exoplanet - stellar metallicity correlation. The frequency of hot super-Earths is not a function of stellar metallicity, also in agreement with observations. Our simulations can reproduce the broad characteristics of the observed super-Earth population.

  12. Effects of Dynamical Evolution of Giant Planets on the Delivery of Atmophile Elements during Terrestrial Planet Formation

    NASA Astrophysics Data System (ADS)

    Matsumura, Soko; Brasser, Ramon; Ida, Shigeru

    2016-02-01

    Recent observations started revealing the compositions of protostellar disks and planets beyond the solar system. In this paper, we explore how the compositions of terrestrial planets are affected by the dynamical evolution of giant planets. We estimate the initial compositions of the building blocks of these rocky planets by using a simple condensation model, and numerically study the compositions of planets formed in a few different formation models of the solar system. We find that the abundances of refractory and moderately volatile elements are nearly independent of formation models, and that all the models could reproduce the abundances of these elements of the Earth. The abundances of atmophile elements, on the other hand, depend on the scattering rate of icy planetesimals into the inner disk, as well as the mixing rate of the inner planetesimal disk. For the classical formation model, neither of these mechanisms are efficient and the accretion of atmophile elements during the final assembly of terrestrial planets appears to be difficult. For the Grand Tack model, both of these mechanisms are efficient, which leads to a relatively uniform accretion of atmophile elements in the inner disk. It is also possible to have a “hybrid” scenario where the mixing is not very efficient but the scattering is efficient. The abundances of atmophile elements in this case increase with orbital radii. Such a scenario may occur in some of the extrasolar planetary systems, which are not accompanied by giant planets or those without strong perturbations from giants. We also confirm that the Grand Tack scenario leads to the distribution of asteroid analogues where rocky planetesimals tend to exist interior to icy ones, and show that their overall compositions are consistent with S-type and C-type chondrites, respectively.

  13. Giant Planet Migration, Disk Evolution, and the Origin of Transitional Disks

    NASA Astrophysics Data System (ADS)

    Alexander, Richard D.; Armitage, Philip J.

    2009-10-01

    We present models of giant planet migration in evolving protoplanetary disks. Our disks evolve subject to viscous transport of angular momentum and photoevaporation, while planets undergo Type II migration. We use a Monte Carlo approach, running large numbers of models with a range in initial conditions. We find that relatively simple models can reproduce both the observed radial distribution of extrasolar giant planets, and the lifetimes and accretion histories of protoplanetary disks. The use of state-of-the-art photoevaporation models results in a degree of coupling between planet formation and disk clearing, which has not been found previously. Some accretion across planetary orbits is necessary if planets are to survive at radii lsim1.5 AU, and if planets of Jupiter mass or greater are to survive in our models they must be able to form at late times, when the disk surface density in the formation region is low. Our model forms two different types of "transitional" disks, embedded planets and clearing disks, which show markedly different properties. We find that the observable properties of these systems are broadly consistent with current observations, and highlight useful observational diagnostics. We predict that young transition disks are more likely to contain embedded giant planets, while older transition disks are more likely to be undergoing disk clearing.

  14. GIANT PLANET MIGRATION, DISK EVOLUTION, AND THE ORIGIN OF TRANSITIONAL DISKS

    SciTech Connect

    Alexander, Richard D.; Armitage, Philip J.

    2009-10-20

    We present models of giant planet migration in evolving protoplanetary disks. Our disks evolve subject to viscous transport of angular momentum and photoevaporation, while planets undergo Type II migration. We use a Monte Carlo approach, running large numbers of models with a range in initial conditions. We find that relatively simple models can reproduce both the observed radial distribution of extrasolar giant planets, and the lifetimes and accretion histories of protoplanetary disks. The use of state-of-the-art photoevaporation models results in a degree of coupling between planet formation and disk clearing, which has not been found previously. Some accretion across planetary orbits is necessary if planets are to survive at radii approx<1.5 AU, and if planets of Jupiter mass or greater are to survive in our models they must be able to form at late times, when the disk surface density in the formation region is low. Our model forms two different types of 'transitional' disks, embedded planets and clearing disks, which show markedly different properties. We find that the observable properties of these systems are broadly consistent with current observations, and highlight useful observational diagnostics. We predict that young transition disks are more likely to contain embedded giant planets, while older transition disks are more likely to be undergoing disk clearing.

  15. THE ANGLO-AUSTRALIAN PLANET SEARCH. XXI. A GAS-GIANT PLANET IN A ONE YEAR ORBIT AND THE HABITABILITY OF GAS-GIANT SATELLITES

    SciTech Connect

    Tinney, C. G.; Wittenmyer, Robert A.; Bailey, Jeremy A.; Horner, J.; Butler, R. Paul; Jones, Hugh R. A.; O'Toole, Simon J.; Carter, Brad D.

    2011-05-01

    We have detected the Doppler signature of a gas-giant exoplanet orbiting the star HD 38283, in an eccentric orbit with a period of almost exactly one year (P = 363.2 {+-} 1.6 d, m sin i = 0.34 {+-} 0.02 M{sub Jup}, e = 0.41 {+-} 0.16). The detection of a planet with period very close to one year critically relied on year-round observation of this circumpolar star. Discovering a planet in a 1 AU orbit around a G dwarf star has prompted us to look more closely at the question of the habitability of the satellites of such planets. Regular satellites orbit all the giant planets in our solar system, suggesting that their formation is a natural by-product of the planet formation process. There is no reason for exomoon formation not to be similarly likely in exoplanetary systems. Moreover, our current understanding of that formation process does not preclude satellite formation in systems where gas giants undergo migration from their formation locations into the terrestrial planet habitable zone. Indeed, regular satellite formation and Type II migration are both linked to the clearing of a gap in the protoplanetary disk by a planet, and so may be inextricably linked. Migration would also multiply the chances of capturing both irregular satellites and Trojan companions sufficiently massive to be habitable. The habitability of such exomoons and exo-Trojans will critically depend on their mass, whether or not they host a magnetosphere, and (for the exomoon case) their orbital radius around the host exoplanet.

  16. High surface magnetic field in red giants as a new signature of planet engulfment?

    NASA Astrophysics Data System (ADS)

    Privitera, Giovanni; Meynet, Georges; Eggenberger, Patrick; Georgy, Cyril; Ekström, Sylvia; Vidotto, Aline A.; Bianda, Michele; Villaver, Eva; ud-Doula, Asif

    2016-09-01

    Context. Red giant stars may engulf planets. This may increase the rotation rate of their convective envelope, which could lead to strong dynamo-triggered magnetic fields. Aims: We explore the possibility of generating magnetic fields in red giants that have gone through the process of a planet engulfment. We compare them with similar models that evolve without any planets. We discuss the impact of magnetic braking through stellar wind on the evolution of the surface velocity of the parent star. Methods: By studying rotating stellar models with and without planets and an empirical relation between the Rossby number and the surface magnetic field, we deduced the evolution of the surface magnetic field along the red giant branch. The effects of stellar wind magnetic braking were explored using a relation deduced from magnetohydrodynamics simulations. Results: The stellar evolution model of a red giant with 1.7 M⊙ without planet engulfment and with a time-averaged rotation velocity during the main sequence equal to 100 km s-1 shows a surface magnetic field triggered by convection that is stronger than 10 G only at the base of the red giant branch, that is, for gravities log g> 3. When a planet engulfment occurs, this magnetic field can also appear at much lower gravities, that is, at much higher luminosities along the red giant branch. The engulfment of a 15 MJ planet typically produces a dynamo-triggered magnetic field stronger than 10 G for gravities between 2.5 and 1.9. We show that for reasonable magnetic braking laws for the wind, the high surface velocity reached after a planet engulfment may be maintained sufficiently long to be observable. Conclusions: High surface magnetic fields for red giants in the upper part of the red giant branch are a strong indication of a planet engulfment or of an interaction with a companion. Our theory can be tested by observing fast-rotating red giants such as HD 31994, Tyc 0347-00762-1, Tyc 5904-00513-1, and Tyc 6054

  17. Giant Impacts During Planet Formation: Parallel Tree Code Simulations Using Smooth Particle Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Cohen, R.; Bodenheimer, P.; Asphaug, E.

    2000-12-01

    There is both theoretical and observational evidence that giant planets collided with objects with mass >= Mearth during their evolution. These impacts may help shorten planetary formation timescales by changing the opacity of the planetary atmosphere to allow quicker cooling. They may also redistribute heavy metals within giant planets, affect the core/envelope mass ratio, and help determine the ratio of emitted to absorbed energy within giant planets. Thus, the researchers propose to simulate the impact of a ~ Earth-mass object onto a proto-giant-planet with SPH. Results of the SPH collision models will be input into a steady-state planetary evolution code and the effect of impacts on formation timescales, core/envelope mass ratios, density profiles, and thermal emissions of giant planets will be quantified. The collision will be modelled using a modified version of an SPH routine which simulates the collision of two polytropes. The Saumon-Chabrier and Tillotson equations of state will replace the polytropic equation of state. The parallel tree algorithm of Olson & Packer will be used for the domain decomposition and neighbor search necessary to calculate pressure and self-gravity efficiently. This work is funded by the NASA Graduate Student Researchers Program.

  18. BD+15 2940 AND HD 233604: TWO GIANTS WITH PLANETS CLOSE TO THE ENGULFMENT ZONE

    SciTech Connect

    Nowak, G.; Niedzielski, A.; Adamow, M.; Maciejewski, G.; Wolszczan, A. E-mail: andrzej.niedzielski@astri.umk.pl E-mail: gracjan.maciejewski@astri.umk.pl

    2013-06-10

    We report the discovery of planetary-mass companions to two red giants by the ongoing Penn State-Torun Planet Search (PTPS) conducted with the 9.2 m Hobby-Eberly Telescope. The 1.1 M{sub Sun} K0-giant, BD+15 2940, has a 1.1 M{sub J} minimum mass companion orbiting the star at a 137.5 day period in a 0.54 AU orbit what makes it the closest-in planet around a giant and possible subject of engulfment as the consequence of stellar evolution. HD 233604, a 1.5 M{sub Sun} K5-giant, is orbited by a 6.6 M{sub J} minimum mass planet which has a period of 192 days and a semi-major axis of only 0.75 AU making it one of the least distant planets to a giant star. The chemical composition analysis of HD 233604 reveals a relatively high {sup 7}Li abundance which may be a sign of its early evolutionary stage or recent engulfment of another planet in the system. We also present independent detections of planetary-mass companions to HD 209458 and HD 88133, and stellar activity-induced radial velocity variations in HD 166435, as part of the discussion of the observing and data analysis methods used in the PTPS project.

  19. Studies of Constraints from the Terrestrial Planets, Asteroid Belt and Giant Planet Obliquities on the Early Solar System Instability

    NASA Astrophysics Data System (ADS)

    Nesvorny, David

    The planetary instability has been invoked as a convenient way to explain several observables in the present Solar System. This theory, frequently referred to under a broad and somewhat ill-defined umbrella as the ‘Nice model’, postulates that at least one of the ice giants suffered scattering encounters with Jupiter and Saturn. This could explain several things, including the excitation of the proper eccentric mode in Jupiter's orbit, survival of the terrestrial planets during giant planet migration, and, if the instability was conveniently delayed, also the Late Heavy Bombardment of the Moon. These properties/events would be unexpected if the migration histories of the outer planets were ideally smooth (at least no comprehensive model has yet been fully developed to collectively explain them). Additional support for the planetary instability comes from the dynamical properties of the asteroid and Kuiper belts, Trojans, and planetary satellites. We created a large database of dynamical evolutions of the outer planets through and 100 Myr past the instability (Nesvorny and Morbidelli 2012. Many of these dynamical histories have been found to match constraints from the orbits of the outer planets themselves. We now propose to test these different scenarios using constraints from the terrestrial planets, asteroid belt and giant planet obliquities. As we explain in the proposal narrative, we will bring all these constraints together in an attempt to develop a comprehensive model of early Solar System's evolution. This will be a significant improvement over the past work, where different constraints were considered piecewise and in various approximations. Our work has the potential to generate support for the Nice-type instability, or to rule it out, which could help in sparking interest in developing better models. RELEVANCE The proposed research is fundamental to understanding the formation and early evolution of the Solar System. This is a central theme of NASA

  20. The Rings of Chariklo under Close Encounters with the Giant Planets

    NASA Astrophysics Data System (ADS)

    Araujo, R. A. N.; Sfair, R.; Winter, O. C.

    2016-06-01

    The Centaur population is composed of minor bodies wandering between the giant planets that frequently perform close gravitational encounters with these planets, leading to a chaotic orbital evolution. Recently, the discovery of two well-defined narrow rings was announced around the Centaur 10199 Chariklo. The rings are assumed to be in the equatorial plane of Chariklo and to have circular orbits. The existence of a well-defined system of rings around a body in such a perturbed orbital region poses an interesting new problem. Are the rings of Chariklo stable when perturbed by close gravitational encounters with the giant planets? Our approach to address this question consisted of forward and backward numerical simulations of 729 clones of Chariklo, with similar initial orbits, for a period of 100 Myr. We found, on average, that each clone experiences during its lifetime more than 150 close encounters with the giant planets within one Hill radius of the planet in question. We identified some extreme close encounters that were able to significantly disrupt or disturb the rings of Chariklo. About 3% of the clones lose their rings and about 4% of the clones have their rings significantly disturbed. Therefore, our results show that in most cases (more than 90%), the close encounters with the giant planets do not affect the stability of the rings in Chariklo-like systems. Thus, if there is an efficient mechanism that creates the rings, then these structures may be common among these kinds of Centaurs.

  1. There might be giants: unseen Jupiter-mass planets as sculptors of tightly packed planetary systems

    NASA Astrophysics Data System (ADS)

    Hands, T. O.; Alexander, R. D.

    2016-03-01

    The limited completeness of the Kepler sample for planets with orbital periods ≳1 yr leaves open the possibility that exoplanetary systems may host undetected giant planets. Should such planets exist, their dynamical interactions with the inner planets may prove vital in sculpting the final orbital configurations of these systems. Using an N-body code with additional forces to emulate the effects of a protoplanetary disc, we perform simulations of the assembly of compact systems of super-Earth-mass planets with unseen giant companions. The simulated systems are analogous to Kepler-11 or Kepler-32 in that they contain four or five inner super-Earths, but our systems also contain longer-period giant companions which are unlikely to have been detected by Kepler. We find that giant companions tend to break widely spaced first-order mean-motion resonances, allowing the inner planets to migrate into tighter resonances. This leads to more compact architectures and increases the occurrence rate of Laplace resonant chains.

  2. Polarization of Directly Imaged Young Giant Planets as a Probe of Mass, Rotation, and Clouds

    NASA Technical Reports Server (NTRS)

    Marley, Mark Scott; Sengupta, Sujan

    2012-01-01

    Young, hot gas giant planets at large separations from their primaries have been directly imaged around several nearby stars. More such planets will likely be detected by ongoing and new imaging surveys with instruments such as the Gemini Planet Imager (GPI). Efforts continue to model the spectra of these planets in order to constrain their masses, effective temperatures, composition, and cloud structure. One potential tool for analyzing these objects, which has received relatively less attention, is polarization. Linear polarization of gas giant exoplanets can arise from the combined influences of light scattering by atmospheric dust and a rotationally distorted shape. The oblateness of gas giant planet increases of course with rotation rate and for fixed rotation also rises with decreasing gravity. Thus young, lower mass gas giant planets with youthful inflated radii could easily have oblateness greater than that of Saturn s 10%. We find that polarizations of over 1% may easily be produced in the near-infrared in such cases. This magnitude of polarization may be measurable by GPI and other instruments. Thus if detected, polarization of a young Jupiter places constraints on the combination of its gravity, rotation rate, and degree of cloudiness. We will present results of our multiple scattering analysis coupled with a self-consistent dusty atmospheric models to demonstrate the range of polarizations that might be expected from resolved exoplanets and the range of parameter space that such observations may inform.

  3. Statistical Study of the Early Solar System's Instability with Four, Five, and Six Giant Planets

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Morbidelli, Alessandro

    2012-10-01

    Several properties of the solar system, including the wide radial spacing and orbital eccentricities of giant planets, can be explained if the early solar system evolved through a dynamical instability followed by migration of planets in the planetesimal disk. Here we report the results of a statistical study, in which we performed nearly 104 numerical simulations of planetary instability starting from hundreds of different initial conditions. We found that the dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, leading to ejection of at least one ice giant from the solar system. Planet ejection can be avoided if the mass of the transplanetary disk of planetesimals was large (M disk >~ 50 M Earth), but we found that a massive disk would lead to excessive dynamical damping (e.g., final e 55 <~ 0.01 compared to present e 55 = 0.044, where e 55 is the amplitude of the fifth eccentric mode in the Jupiter's orbit), and to smooth migration that violates constraints from the survival of the terrestrial planets. Better results were obtained when the solar system was assumed to have five giant planets initially, and one ice giant, with mass comparable to that of Uranus and Neptune, was ejected into interstellar space by Jupiter. The best results were obtained when the ejected planet was placed into the external 3:2 or 4:3 resonance with Saturn and M disk ~= 20 M Earth. The range of possible outcomes is rather broad in this case, indicating that the present solar system is neither a typical nor expected result for a given initial state, and occurs, in best cases, with only a sime5% probability (as defined by the success criteria described in the main text). The case with six giant planets shows interesting dynamics but does offer significant advantages relative to the five-planet case.

  4. Hilda Asteroid Colors: Insight into Giant Planet Migration?

    NASA Astrophysics Data System (ADS)

    Sharkey, Benjamin; Ryan, Erin L.; Woodward, Charles E.; Noll, Keith S.

    2016-01-01

    The Hilda asteroids are a unique population of small bodies that are locked in a 3:2 mean motion resonance with Jupiter. Unlike other resonances in the asteroid belt, the 3:2 is a stable resonance at 3.95 AU. Objects at this resonance have stable orbits for at least 2 GYr and, more likely, for the age of the Solar System. In an instantaneous top down view of the solar system, the Hildas approximately trace a triangle with over-densities of asteroids near the L3, L4 and L5 Jovian Lagrange points. This configuration is cited as evidence that Jupiter migrated inwards by ~0.4 AU. Stable Hilda orbits have mean eccentricities of 0.16 with typical perihelia of 3.15 AU. These latter properties, in terms of observability and accessibility to spacecraft, are a major advantage that distinguishes the Hildas from other populations of potential scientific interest such as the Jovian Trojans. The Outer Main Belt (OMB) also has many objects that may have originated in the outer protoplanetary disk (OPD). However, the OMB appears to be more mixed with objects from elsewhere in the Main Belt and enjoys only a small advantage in terms of brightness for a given diameter and albedo. The intrinsic collisional probability for objects in the Hilda population is also a factor of 3 to 5 less than the collisional probabilities for Trojan and OMB populations. Thus, the Hildas likely represent a significant population of objects unaltered due to collisional processing. Here we discuss findings of our ongoing NASA Planetary Astronomy program to obtain Sloan optical (g' r' i' z') colors of Hilda-group asteroids. The loci of these colors are compared to the Kuiper Belt populations to test post-formation migration effects of the giant planets in our solar system on the small body population. In part, this work was conducted as part of a University of Minnesota Undergraduate Research Scholarship, and is supported by NASA PAST Award NNX13AJ11G.

  5. The HARPS search for southern extra-solar planets. XXVI. Two giant planets around M0 dwarfs

    NASA Astrophysics Data System (ADS)

    Forveille, T.; Bonfils, X.; Lo Curto, G.; Delfosse, X.; Udry, S.; Bouchy, F.; Lovis, C.; Mayor, M.; Moutou, C.; Naef, D.; Pepe, F.; Perrier, C.; Queloz, D.; Santos, N.

    2011-02-01

    Fewer giants planets are found around M dwarfs than around more massive stars, and this dependence of planetary characteristics on the mass of the central star is an important observational diagnostic of planetary formation theories. In part to improve on those statistics, we are monitoring the radial velocities of nearby M dwarfs with the HARPS spectrograph on the ESO 3.6 m telescope. We present here the detection of giant planets around two nearby M0 dwarfs: planets, with minimum masses of respectively 5 Jupiter masses and 1 Saturn mass, orbit around Gl 676A and HIP 12961. The latter is, by over a factor of two, the most massive planet found by radial velocity monitoring of an M dwarf, but its being found around an early M-dwarf is in approximate line with the upper envelope of the planetary vs stellar mass diagram. HIP 12961 ([Fe/H] = -0.07) is slightly more metal-rich than the average solar neighborhood ([Fe/H] = -0.17), and Gl 676A ([Fe/H] = 0.18) significantly so. The two stars together therefore reinforce the growing trend for giant planets being more frequent around more metal-rich M dwarfs, and the 5 Jupiter mass Gl 676Ab being found around a metal-rich star is consistent with the expectation that the most massive planets preferentially form in disks with large condensate masses. Based on observations made with the HARPS instrument on the ESO 3.6-m telescope at La Silla Observatory under program ID 072.C-0488Tables 3 and 4 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/cgi-bin/qcat?J/A+A/526/A141

  6. PEERING INTO THE GIANT-PLANET-FORMING REGION OF THE TW HYDRAE DISK WITH THE GEMINI PLANET IMAGER

    SciTech Connect

    Rapson, Valerie A.; Kastner, Joel H.; Millar-Blanchaer, Maxwell A.; Dong, Ruobing

    2015-12-20

    We present Gemini Planet Imager (GPI) adaptive optics near-infrared images of the giant-planet-forming regions of the protoplanetary disk orbiting the nearby (D = 54 pc), pre-main-sequence (classical T Tauri) star TW Hydrae. The GPI images, which were obtained in coronagraphic/polarimetric mode, exploit starlight scattered off small dust grains to elucidate the surface density structure of the TW Hya disk from ∼80 AU to within ∼10 AU of the star at ∼1.5 AU resolution. The GPI polarized intensity images unambiguously confirm the presence of a gap in the radial surface brightness distribution of the inner disk. The gap is centered near ∼23 AU, with a width of ∼5 AU and a depth of ∼50%. In the context of recent simulations of giant-planet formation in gaseous, dusty disks orbiting pre-main-sequence stars, these results indicate that at least one young planet with a mass ∼0.2 M{sub J} could be present in the TW Hya disk at an orbital semimajor axis similar to that of Uranus. If this (proto)planet is actively accreting gas from the disk, it may be readily detectable by GPI or a similarly sensitive, high-resolution infrared imaging system.

  7. Peering into the Giant-planet-forming Region of the TW Hydrae Disk with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Rapson, Valerie A.; Kastner, Joel H.; Millar-Blanchaer, Maxwell A.; Dong, Ruobing

    2015-12-01

    We present Gemini Planet Imager (GPI) adaptive optics near-infrared images of the giant-planet-forming regions of the protoplanetary disk orbiting the nearby (D = 54 pc), pre-main-sequence (classical T Tauri) star TW Hydrae. The GPI images, which were obtained in coronagraphic/polarimetric mode, exploit starlight scattered off small dust grains to elucidate the surface density structure of the TW Hya disk from ∼80 AU to within ∼10 AU of the star at ∼1.5 AU resolution. The GPI polarized intensity images unambiguously confirm the presence of a gap in the radial surface brightness distribution of the inner disk. The gap is centered near ∼23 AU, with a width of ∼5 AU and a depth of ∼50%. In the context of recent simulations of giant-planet formation in gaseous, dusty disks orbiting pre-main-sequence stars, these results indicate that at least one young planet with a mass ∼0.2 MJ could be present in the TW Hya disk at an orbital semimajor axis similar to that of Uranus. If this (proto)planet is actively accreting gas from the disk, it may be readily detectable by GPI or a similarly sensitive, high-resolution infrared imaging system.

  8. Layered double diffusive convection: From Earth oceans to giant planet interiors.

    NASA Astrophysics Data System (ADS)

    Leconte, J.; Chabrier, G.

    2012-12-01

    Many unknowns remain concerning the internal structure and composition of giant gaseous planets. The existence and the properties of an hypothetical central core, in particular, are still debated. Contrary to conventional interior models for giant (exo)planets, we consider an inhomogeneous mixing of heavy elements in the gaseous H/He envelope of these objects. As in the oceans, such compositional gradients can give rise to layered convection which impedes large scale convection, yielding a hotter, super adiabatic interior. As a result, the metal enrichment predicted by this model is up to 30 to 60% larger than previously thought for Jupiter and Saturn. However, metals are preferentially redistributed in the gaseous envelope and coreless models can be found for Jupiter. This inefficient, layered convection, yielding a slower cooling, can help to explain anomalously inflated Hot Jupiters, but also opens a new window on our understanding of giant planet formation and history inside our Solar System.

  9. FORMATION OF GIANT PLANETS BY DISK INSTABILITY ON WIDE ORBITS AROUND PROTOSTARS WITH VARIED MASSES

    SciTech Connect

    Boss, Alan P.

    2011-04-10

    Doppler surveys have shown that more massive stars have significantly higher frequencies of giant planets inside {approx}3 AU than lower mass stars, consistent with giant planet formation by core accretion. Direct imaging searches have begun to discover significant numbers of giant planet candidates around stars with masses of {approx}1 M{sub sun} to {approx}2 M{sub sun} at orbital distances of {approx}20 AU to {approx}120 AU. Given the inability of core accretion to form giant planets at such large distances, gravitational instabilities of the gas disk leading to clump formation have been suggested as the more likely formation mechanism. Here, we present five new models of the evolution of disks with inner radii of 20 AU and outer radii of 60 AU, for central protostars with masses of 0.1, 0.5, 1.0, 1.5, and 2.0 M{sub sun}, in order to assess the likelihood of planet formation on wide orbits around stars with varied masses. The disk masses range from 0.028 M{sub sun} to 0.21 M{sub sun}, with initial Toomre Q stability values ranging from 1.1 in the inner disks to {approx}1.6 in the outer disks. These five models show that disk instability is capable of forming clumps on timescales of {approx}10{sup 3} yr that, if they survive for longer times, could form giant planets initially on orbits with semimajor axes of {approx}30 AU to {approx}70 AU and eccentricities of {approx}0 to {approx}0.35, with initial masses of {approx}1 M{sub Jup} to {approx}5 M{sub Jup}, around solar-type stars, with more protoplanets forming as the mass of the protostar (and protoplanetary disk) is increased. In particular, disk instability appears to be a likely formation mechanism for the HR 8799 gas giant planetary system.

  10. Giant Planets in Open Clusters and Binaries: Observational Constraints on Migration

    NASA Astrophysics Data System (ADS)

    Quinn, Samuel N.; White, Russel J.; Latham, David W.; Buchhave, Lars A.; Torres, Guillermo

    2016-01-01

    Some giant planets migrate from their birthplace beyond the ice line to short-period orbits just a fraction of an AU from their host stars. Though many theories have been proposed, it is not yet clear which mechanism is most important for migration, and by extension, in which types of planetary system we can expect a greater prevalence of disruptive gas giant migration. One way to constrain this process is to observe the orbital properties of migrating planets, which are expected to be shaped according to the mode of migration: in general, interaction with the gas disk should produce circular, coplanar orbits, while multi-body processes stir up eccentricities and inclinations. Unfortunately, tidal and magnetic interactions between hot Jupiters and their host stars can obscure these differences by damping eccentricities and inclinations over time, so the most direct constraints will come from difficult-to-observe young systems. Additional constraints on migration can be obtained by observing the architectures of systems containing short-period giant planets: if an outer companion is often responsible for driving migration, there should be a higher incidence of massive companions on wide orbits in hot Jupiter systems than in systems not hosting a short-period giant planet. Further, the properties of these outer companions can help differentiate between multi-body migration mechanisms. We describe two complementary surveys that we have carried out to address these problems. The first, a precise radial-velocity survey in nearby adolescent (100-600 Myr) open clusters, characterizes the orbits of giant planets soon after migration. The second, an adaptive optics imaging survey of hot Jupiter host stars, constrains the population of wide companions in hot Jupiter systems. We present the results from these two surveys and discuss the orbital properties and system architectures of our discoveries in the context of giant planet migration.

  11. SOLUBILITY OF WATER ICE IN METALLIC HYDROGEN: CONSEQUENCES FOR CORE EROSION IN GAS GIANT PLANETS

    SciTech Connect

    Wilson, H. F.; Militzer, B.

    2012-01-20

    Using ab initio simulations we investigate whether water ice is stable in the cores of giant planets, or whether it dissolves into the layer of metallic hydrogen above. By Gibbs free energy calculations we find that for pressures between 10 and 40 Mbar the ice-hydrogen interface is thermodynamically unstable at temperatures above approximately 3000 K, far below the temperature of the core-mantle boundaries in Jupiter and Saturn. This implies that the dissolution of core material into the fluid layers of giant planets is thermodynamically favored, and that further modeling of the extent of core erosion is warranted.

  12. Characterizing transiting extrasolar giant planets: On companions, rings, and love handles

    NASA Astrophysics Data System (ADS)

    Barnes, Jason Wayne

    2004-10-01

    For my Ph.D. research I investigated the prospects for characterizing transiting extrasolar giant planets from their transit lightcurves. Hubble Space Telescope photometry of transiting planet HD209458b revealed that the planet has no moons. Here, I show that tidal orbital evolution of moons limits their lifetimes, and hence that no moons larger than Amalthea in size should survive around HD209458b, consistent with observations. I then calculate the detectability and scientific potential of planetary rings and oblateness. Oblateness will prove difficult to reliably detect, even with the Hubble Space Telescope. However, large Saturn-like ring systems should be easy to find around transiting extrasolar giant planets if such rings exist.

  13. CONSEQUENCES OF THE EJECTION AND DISRUPTION OF GIANT PLANETS

    SciTech Connect

    Guillochon, James; Ramirez-Ruiz, Enrico; Lin, Douglas

    2011-05-10

    The discovery of Jupiter-mass planets in close orbits about their parent stars has challenged models of planet formation. Recent observations have shown that a number of these planets have highly inclined, sometimes retrograde orbits about their parent stars, prompting much speculation as to their origin. It is known that migration alone cannot account for the observed population of these misaligned hot Jupiters, which suggests that dynamical processes after the gas disk dissipates play a substantial role in yielding the observed inclination and eccentricity distributions. One particularly promising candidate is planet-planet scattering, which is not very well understood in the nonlinear regime of tides. Through three-dimensional hydrodynamical simulations of multi-orbit encounters, we show that planets that are scattered into an orbit about their parent stars with closest approach distance being less than approximately three times the tidal radius are either destroyed or completely ejected from the system. We find that as few as 9 and as many as 12 of the currently known hot Jupiters have a maximum initial apastron for scattering that lies well within the ice line, implying that these planets must have migrated either before or after the scattering event that brought them to their current positions. If stellar tides are unimportant (Q{sub *} {approx}> 10{sup 7}), disk migration is required to explain the existence of the hot Jupiters present in these systems. Additionally, we find that the disruption and/or ejection of Jupiter-mass planets deposits a Sun's worth of angular momentum onto the host star. For systems in which planet-planet scattering is common, we predict that planetary hosts have up to a 35% chance of possessing an obliquity relative to the invariable plane of greater than 90{sup 0}.

  14. A Program To Detect and Characterize Extra-Solar Giant Planets

    NASA Technical Reports Server (NTRS)

    Noyes, Robert W.; Boyce, Joseph M. (Technical Monitor)

    2001-01-01

    This grant report highlights activity in the following areas: (1) Improvement in Precise Radial Velocity (PRV) analysis code; (2) Reanalysis of previous data; (3) Improvements to the AFOE (Advanced Fiber Optic Echelle) spectrograph; (4) Development of PRV capabilities for the Hectochelle; (5) Extra-solar planet studies; (6) Longer-term plans for the AFOE; (7) Completion and publication of the analysis of the transiting gas-giant planet HD 209458b.

  15. Making Planet Nine: A Scattered Giant in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Bromley, Benjamin C.; Kenyon, Scott J.

    2016-07-01

    Correlations in the orbits of several minor planets in the outer solar system suggest the presence of a remote, massive Planet Nine. With at least 10 times the mass of the Earth and a perihelion well beyond 100 au, Planet Nine poses a challenge to planet formation theory. Here we expand on a scenario in which the planet formed closer to the Sun and was gravitationally scattered by Jupiter or Saturn onto a very eccentric orbit in an extended gaseous disk. Dynamical friction with the gas then allowed the planet to settle in the outer solar system. We explore this possibility with a set of numerical simulations. Depending on how the gas disk evolves, scattered super-Earths or small gas giants settle on a range of orbits, with perihelion distances as large as 300 au. Massive disks that clear from the inside out on million-year timescales yield orbits that allow a super-Earth or gas giant to shepherd the minor planets as observed. A massive planet can achieve a similar orbit in a persistent, low-mass disk over the lifetime of the solar system.

  16. The In Situ Formation of Giant Planets at Short Orbital Periods

    NASA Astrophysics Data System (ADS)

    Boley, Aaron C.; Gladman, Brett; Granados Contreras, A. Paula

    2016-05-01

    We propose that two of the most surprising results so far among exoplanet discoveries are related: the existences of both hot Jupiters and the high frequency of multi-planet systems with periods P < 200 days. In this paradigm, the vast majority of stars rapidly form along with multiple close-in planets in the mass range of Mars to super-Earths/mini-Neptunes. Such systems of tightly packed inner planets are metastable, with the time scale of the dynamical instability having a major influence on final planet types. In most cases, the planets consolidate into a system of fewer, more massive planets, but long after the circumstellar gas disk has dissipated. This can yield planets with masses above the traditional critical core of ~10 Mearth yielding short-period giants that lack abundant gas. A rich variety of physical states are also possible given the range of collisional outcomes and formation time of the close-in planets. However, when dynamical consolidation occurs before gas dispersal, a critical core can form that then grows via gas capture into a short-period gas giant. In this picture the majority of Hot and Warm Jupiters formed locally, rather than migrating down from larger distances.

  17. The In Situ Formation of Giant Planets at Short Orbital Periods

    NASA Astrophysics Data System (ADS)

    Boley, A. C.; Granados Contreras, A. P.; Gladman, B.

    2016-02-01

    We propose that two of the most surprising results so far among exoplanet discoveries are related: the existences of both hot Jupiters and the high frequency of multi-planet systems with periods P ≲ 200 days. In this paradigm, the vast majority of stars rapidly form along with multiple close-in planets in the mass range of Mars to super-Earths/mini-Neptunes. Such systems of tightly packed inner planets are metastable, with the time scale of the dynamical instability having a major influence on final planet types. In most cases, the planets consolidate into a system of fewer, more massive planets, but long after the circumstellar gas disk has dissipated. This can yield planets with masses above the traditional critical core of ∼10 M⊕, yielding short-period giants that lack abundant gas. A rich variety of physical states are also possible given the range of collisional outcomes and formation time of the close-in planets. However, when dynamical consolidation occurs before gas dispersal, a critical core can form that then grows via gas capture into a short-period gas giant. In this picture the majority of Hot and Warm Jupiters formed locally, rather than migrating down from larger distances.

  18. WARM DEBRIS DISKS PRODUCED BY GIANT IMPACTS DURING TERRESTRIAL PLANET FORMATION

    SciTech Connect

    Genda, H.; Kobayashi, H.; Kokubo, E.

    2015-09-10

    In our solar system, Mars-sized protoplanets frequently collided with each other during the last stage of terrestrial planet formation, called the giant impact stage. Giant impacts eject a large amount of material from the colliding protoplanets into the terrestrial planet region, which may form debris disks with observable infrared excesses. Indeed, tens of warm debris disks around young solar-type stars have been observed. Here we quantitatively estimate the total mass of ejected materials during the giant impact stages. We found that ∼0.4 times the Earth’s mass is ejected in total throughout the giant impact stage. Ejected materials are ground down by collisional cascade until micron-sized grains are blown out by radiation pressure. The depletion timescale of these ejected materials is determined primarily by the mass of the largest body among them. We conducted high-resolution simulations of giant impacts to accurately obtain the mass of the largest ejected body. We then calculated the evolution of the debris disks produced by a series of giant impacts and depleted by collisional cascades to obtain the infrared excess evolution of the debris disks. We found that the infrared excess is almost always higher than the stellar infrared flux throughout the giant impact stage (∼100 Myr) and is sometimes ∼10 times higher immediately after a giant impact. Therefore, giant impact stages would explain the infrared excess from most observed warm debris disks. The observed fraction of stars with warm debris disks indicates that the formation probability of our solar-system-like terrestrial planets is approximately 10%.

  19. Transits of extrasolar moons around luminous giant planets

    NASA Astrophysics Data System (ADS)

    Heller, R.

    2016-04-01

    Beyond Earth-like planets, moons can be habitable, too. No exomoons have been securely detected, but they could be extremely abundant. Young Jovian planets can be as hot as late M stars, with effective temperatures of up to 2000 K. Transits of their moons might be detectable in their infrared photometric light curves if the planets are sufficiently separated (≳10 AU) from the stars to be directly imaged. The moons will be heated by radiation from their young planets and potentially by tidal friction. Although stellar illumination will be weak beyond 5 AU, these alternative energy sources could liquify surface water on exomoons for hundreds of Myr. A Mars-mass H2O-rich moon around β Pic b would have a transit depth of 1.5 × 10-3, in reach of near-future technology.

  20. On the orbital evolution of a pair of giant planets in mean motion resonance

    NASA Astrophysics Data System (ADS)

    André, Q.; Papaloizou, J. C. B.

    2016-10-01

    Pairs of extrasolar giant planets in a mean motion commensurability are common with 2:1 resonance occurring most frequently. Disc-planet interaction provides a mechanism for their origin. However, the time-scale on which this could operate in particular cases is unclear. We perform 2D and 3D numerical simulations of pairs of giant planets in a protoplanetary disc as they form and maintain a mean motion commensurability. We consider systems with current parameters similar to those of HD 155358, 24 Sextantis and HD 60532, and disc models of varying mass, decreasing mass corresponding to increasing age. For the lowest mass discs, systems with planets in the Jovian mass range migrate inwards maintaining a 2:1 commensurability. Systems with the inner planet currently at around 1 au from the central star could have originated at a few au and migrated inwards on a time-scale comparable to protoplanetary disc lifetimes. Systems of larger mass planets such as HD 60532 attain 3:1 resonance as observed. For a given mass accretion rate, results are insensitive to the disc model for the range of viscosity prescriptions adopted, there being good agreement between 2D and 3D simulations. However, in a higher mass disc a pair of Jovian mass planets passes through 2:1 resonance before attaining a temporary phase lasting a few thousand orbits in an unstable 5:3 resonance prior to undergoing a scattering. Thus, finding systems in this commensurability is unlikely.

  1. Gravitational scattering as a possible origin for giant planets at small stellar distances.

    PubMed

    Weidenschilling, S J; Marzari, F

    The recent discoveries of massive planetary companions orbiting several solar-type stars pose a conundrum. Conventional models for the formation of giant planets (such as Jupiter and Saturn) place such objects at distances of several astronomical units from the parent star, whereas all but one of the new objects are on orbits well inside 1 AU; these planets must therefore have originated at larger distances and subsequently migrated inwards. One suggested migration mechanism invokes tidal interactions between the planet and the evolving circumstellar disk. Such a mechanism results in planets with small, essentially circular orbits, which appears to be the case for many of the new planets. But two of the objects have substantial orbital eccentricities, which are difficult to reconcile with a tidal-linkage model. Here we describe an alternative model for planetary migration that can account for these large orbital eccentricities. If a system of three or more giant planets form about a star, their orbits may become unstable as they gain mass by accreting gas from the circumstellar disk; subsequent gravitational encounters among these planets can eject one from the system while placing the others into highly eccentric orbits both closer and farther from the star.

  2. Planet traps and first planets: The critical metallicity for gas giant formation

    SciTech Connect

    Hasegawa, Yasuhiro; Hirashita, Hiroyuki E-mail: hirashita@asiaa.sinica.edu.tw

    2014-06-10

    The ubiquity of planets poses an interesting question: when are first planets formed in galaxies? We investigate this by adopting a theoretical model where planet traps are combined with the standard core accretion scenario in which the efficiency of forming planetary cores directly relates to the metallicity ([Fe/H]) in disks. Three characteristic exoplanetary populations are examined: hot Jupiters, exo-Jupiters around 1 AU, and low-mass planets in tight orbits, such as super-Earths. We statistically compute planet formation frequencies (PFFs), as well as the orbital radius (〈R{sub rapid}〉) within which gas accretion becomes efficient enough to form Jovian planets, as a function of metallicity (–2 ≤ [Fe/H] ≤–0.6). We show that the total PFFs for these three populations increase steadily with metallicity. This is the direct outcome of the core accretion picture. For the metallicity range considered here, the population of low-mass planets dominates Jovian planets. The Jovian planets contribute to the PFFs above [Fe/H] ≅ –1. We find that the hot Jupiters form more efficiently than the exo-Jupiters at [Fe/H] ≲ –0.7. This arises from the slower growth of planetary cores and their more efficient radial inward transport by the host traps in lower metallicity disks. We show that the critical metallicity for forming Jovian planets is [Fe/H] ≅ –1.2 by comparing 〈R{sub rapid}〉 of hot Jupiters and low-mass planets. The comparison intrinsically links to the different gas accretion efficiency between these two types of planets. Therefore, this study implies that important physical processes in planet formation may be tested by exoplanet observations around metal-poor stars.

  3. SOLUBILITY OF IRON IN METALLIC HYDROGEN AND STABILITY OF DENSE CORES IN GIANT PLANETS

    SciTech Connect

    Wahl, Sean M.; Wilson, Hugh F.; Militzer, Burkhard

    2013-08-20

    The formation of the giant planets in our solar system, and likely a majority of giant exoplanets, is most commonly explained by the accretion of nebular hydrogen and helium onto a large core of terrestrial-like composition. The fate of this core has important consequences for the evolution of the interior structure of the planet. It has recently been shown that H{sub 2}O, MgO, and SiO{sub 2} dissolve in liquid metallic hydrogen at high temperature and pressure. In this study, we perform ab initio calculations to study the solubility of an innermost metallic core. We find dissolution of iron to be strongly favored above 2000 K over the entire pressure range (0.4-4 TPa) considered. We compare with and summarize the results for solubilities on other probable core constituents. The calculations imply that giant planet cores are in thermodynamic disequilibrium with surrounding layers, promoting erosion and redistribution of heavy elements. Differences in solubility behavior between iron and rock may influence evolution of interiors, particularly for Saturn-mass planets. Understanding the distribution of iron and other heavy elements in gas giants may be relevant in understanding mass-radius relationships, as well as deviations in transport properties from pure hydrogen-helium mixtures.

  4. Origin of the orbital architecture of the giant planets of the Solar System.

    PubMed

    Tsiganis, K; Gomes, R; Morbidelli, A; Levison, H F

    2005-05-26

    Planetary formation theories suggest that the giant planets formed on circular and coplanar orbits. The eccentricities of Jupiter, Saturn and Uranus, however, reach values of 6 per cent, 9 per cent and 8 per cent, respectively. In addition, the inclinations of the orbital planes of Saturn, Uranus and Neptune take maximum values of approximately 2 degrees with respect to the mean orbital plane of Jupiter. Existing models for the excitation of the eccentricity of extrasolar giant planets have not been successfully applied to the Solar System. Here we show that a planetary system with initial quasi-circular, coplanar orbits would have evolved to the current orbital configuration, provided that Jupiter and Saturn crossed their 1:2 orbital resonance. We show that this resonance crossing could have occurred as the giant planets migrated owing to their interaction with a disk of planetesimals. Our model reproduces all the important characteristics of the giant planets' orbits, namely their final semimajor axes, eccentricities and mutual inclinations.

  5. Origin of the orbital architecture of the giant planets of the Solar System.

    PubMed

    Tsiganis, K; Gomes, R; Morbidelli, A; Levison, H F

    2005-05-26

    Planetary formation theories suggest that the giant planets formed on circular and coplanar orbits. The eccentricities of Jupiter, Saturn and Uranus, however, reach values of 6 per cent, 9 per cent and 8 per cent, respectively. In addition, the inclinations of the orbital planes of Saturn, Uranus and Neptune take maximum values of approximately 2 degrees with respect to the mean orbital plane of Jupiter. Existing models for the excitation of the eccentricity of extrasolar giant planets have not been successfully applied to the Solar System. Here we show that a planetary system with initial quasi-circular, coplanar orbits would have evolved to the current orbital configuration, provided that Jupiter and Saturn crossed their 1:2 orbital resonance. We show that this resonance crossing could have occurred as the giant planets migrated owing to their interaction with a disk of planetesimals. Our model reproduces all the important characteristics of the giant planets' orbits, namely their final semimajor axes, eccentricities and mutual inclinations. PMID:15917800

  6. Expected Storage of Nanobacteria Fossils in the Lunar Interior Transported from Old Planets by Giant Impact

    NASA Astrophysics Data System (ADS)

    Miura, Yas.

    2010-04-01

    1) The Moon has impact remnants from planetary giant impact of Ca-rich plagioclases, C and Cl-bearing breccias, and probable CO2 fluids in the lunar interior. 2) There will be nano-fossils stored in the lunar crust of separated blocks of old planets.

  7. DETECTING THE WIND-DRIVEN SHAPES OF EXTRASOLAR GIANT PLANETS FROM TRANSIT PHOTOMETRY

    SciTech Connect

    Barnes, Jason W.; Cooper, Curtis S.; Showman, Adam P.; Hubbard, William B.

    2009-11-20

    Several processes can cause the shape of an extrasolar giant planet's shadow, as viewed in transit, to depart from circular. In addition to rotational effects, cloud formation, non-homogenous haze production and movement, and dynamical effects (winds) could also be important. When such a planet transits its host star as seen from the Earth, the asphericity will introduce a deviation in the transit light curve relative to the transit of a perfectly spherical (or perfectly oblate) planet. We develop a theoretical framework to interpret planetary shapes. We then generate predictions for transiting planet shapes based on a published theoretical dynamical model of HD189733b. Using these shape models we show that planet shapes are unlikely to introduce detectable light-curve deviations (those >1 x 10{sup -5} of the host star), but that the shapes may lead to astrophysical sources of systematic error when measuring planetary oblateness, transit time, and impact parameter.

  8. The SOPHIE search for northern extrasolar planets. X. Detection and characterization of giant planets by the dozen

    NASA Astrophysics Data System (ADS)

    Hébrard, G.; Arnold, L.; Forveille, T.; Correia, A. C. M.; Laskar, J.; Bonfils, X.; Boisse, I.; Díaz, R. F.; Hagelberg, J.; Sahlmann, J.; Santos, N. C.; Astudillo-Defru, N.; Borgniet, S.; Bouchy, F.; Bourrier, V.; Courcol, B.; Delfosse, X.; Deleuil, M.; Demangeon, O.; Ehrenreich, D.; Gregorio, J.; Jovanovic, N.; Labrevoir, O.; Lagrange, A.-M.; Lovis, C.; Lozi, J.; Moutou, C.; Montagnier, G.; Pepe, F.; Rey, J.; Santerne, A.; Ségransan, D.; Udry, S.; Vanhuysse, M.; Vigan, A.; Wilson, P. A.

    2016-04-01

    We present new radial velocity measurements of eight stars that were secured with the spectrograph SOPHIE at the 193 cm telescope of the Haute-Provence Observatory. The measurements allow detecting and characterizing new giant extrasolar planets. The host stars are dwarfs of spectral types between F5 and K0 and magnitudes of between 6.7 and 9.6; the planets have minimum masses Mp sin i of between 0.4 to 3.8 MJup and orbitalperiods of several days to several months. The data allow only single planets to be discovered around the first six stars (HD 143105, HIP 109600, HD 35759, HIP 109384, HD 220842, and HD 12484), but one of them shows the signature of an additional substellar companion in the system. The seventh star, HIP 65407, allows the discovery of two giant planets that orbit just outside the 12:5 resonance in weak mutual interaction. The last star, HD 141399, was already known to host a four-planet system; our additional data and analyses allow new constraints to be set on it. We present Keplerian orbits of all systems, together with dynamical analyses of the two multi-planet systems. HD 143105 is one of the brightest stars known to host a hot Jupiter, which could allow numerous follow-up studies to be conducted even though this is not a transiting system. The giant planets HIP 109600b, HIP 109384b, and HD 141399c are located in the habitable zone of their host star. Based on observations collected with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France, by the SOPHIE Consortium (programs 07A.PNP.CONS to 15A.PNP.CONS).Full version of the SOPHIE measurements (Table 1) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A145

  9. An extrasolar giant planet in a close triple-star system.

    PubMed

    Konacki, Maciej

    2005-07-14

    Hot Jupiters are gas-giant planets orbiting with periods of 3-9 days around Sun-like stars. They are believed to form in a disk of gas and condensed matter at or beyond approximately 2.7 astronomical units (au-the Sun-Earth distance) from their parent star. At such distances, there exists a sufficient amount of solid material to produce a core capable of capturing enough gas to form a giant planet. Subsequently, they migrate inward to their present close orbits. Here I report the detection of an unusual hot Jupiter orbiting the primary star of a triple stellar system, HD 188753. The planet has an orbital period of 3.35 days and a minimum mass of 1.14 times that of Jupiter. The primary star's mass is 1.06 times that of the Sun, 1.06 M(\\circ). The secondary star, itself a binary stellar system, orbits the primary at an average distance of 12.3 au with an eccentricity of 0.50. The mass of the secondary pair is 1.63 M(\\circ). Such a close and massive secondary would have truncated a disk around the primary to a radius of only approximately 1.3 AU (ref. 4) and might have heated it up to temperatures high enough to prohibit giant-planet formation, leaving the origin of this planet unclear.

  10. Origin of the obliquities of the giant planets in mutual interactions in the early Solar System.

    PubMed

    Brunini, Adrián

    2006-04-27

    The origin of the spin-axis orientations (obliquities) of the giant planets is a fundamental issue because if the obliquities resulted from tangential collisions with primordial Earth-sized protoplanets, then they are related to the masses of the largest planetesimals out of which the planets form. A problem with this mechanism, however, is that the orbital planes of regular satellites would probably be uncorrelated with the obliquities, contrary to observations. Alternatively, they could have come from an external twist that affected the orientation of the Solar System plane; but in this model, the outer planets must have formed too rapidly, before the event that produced the twist. Moreover, the model cannot be quantitatively tested. Here I show that the present obliquities of the giant planets were probably achieved when Jupiter and Saturn crossed the 1:2 orbital resonance during a specific migration process: different migration scenarios cannot account for the large observed obliquities. The existence of the regular satellites of the giant planets does not represent a problem in this model because, although they formed soon after the planetary formation, they can follow the slow evolution of the equatorial plane it produces. PMID:16641989

  11. Hydrogen-water mixtures in giant planet interiors studied with ab initio simulations

    NASA Astrophysics Data System (ADS)

    Soubiran, F.; Militzer, B.

    2015-12-01

    We study water-hydrogen mixtures under planetary interior conditions using ab initio molecular dynamics simulations. We determine the thermodynamic properties of various water-hydrogen mixing ratios at temperatures of 2000 and 6000 K for pressures of a few tens of GPa. These conditions are relevant for ice giant planets and for the outer envelope of the gas giants. We find that at 2000 K the mixture is in a molecular regime, while at 6000 K the dissociation of hydrogen and water is important and affects the thermodynamic properties. We study the structure of the liquid and analyze the radial distribution function. We provide estimates for the transport properties, diffusion and viscosity, based on autocorrelation functions. We obtained viscosity estimates of the order of a few tenths of mPa s for the conditions under consideration. These results are relevant for dynamo simulations of ice giant planets.

  12. BD+48 740-Li OVERABUNDANT GIANT STAR WITH A PLANET: A CASE OF RECENT ENGULFMENT?

    SciTech Connect

    Adamow, M.; Niedzielski, A.; Nowak, G.; Villaver, E.; Wolszczan, A.

    2012-07-20

    We report the discovery of a unique object, BD+48 740, a lithium overabundant giant with A(Li) = 2.33 {+-} 0.04 (where A(Li) = log n{sub Li}/n{sub H} + 12), that exhibits radial velocity (RV) variations consistent with a 1.6 M{sub J} companion in a highly eccentric, e = 0.67 {+-} 0.17, and extended, a 1.89 AU (P = 771 days), orbit. The high eccentricity of the planet is uncommon among planetary systems orbiting evolved stars and so is the high lithium abundance in a giant star. The ingestion by the star of a putative second planet in the system originally in a closer orbit could possibly allow for a single explanation to these two exceptional facts. If the planet candidate is confirmed by future RV observations, it might represent the first example of the remnant of a multiple planetary system recently affected by stellar evolution.

  13. Insights into Planet Formation from Debris Disks - II. Giant Impacts in Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Wyatt, Mark C.; Jackson, Alan P.

    2016-03-01

    Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most Solar System bodies bear signatures of such collisions. Current planet formation models predict that an epoch of giant impacts may be inevitable, and observations of debris around other stars are providing mounting evidence that giant impacts feature in the evolution of many planetary systems. This chapter reviews giant impacts, focussing on what we can learn about planet formation by studying debris around other stars. Giant impact debris evolves through mutual collisions and dynamical interactions with planets. General aspects of this evolution are outlined, noting the importance of the collision-point geometry. The detectability of the debris is discussed using the example of the Moon-forming impact. Such debris could be detectable around another star up to 10 Myr post-impact, but model uncertainties could reduce detectability to a few 100 yr window. Nevertheless the 3 % of young stars with debris at levels expected during terrestrial planet formation provide valuable constraints on formation models; implications for super-Earth formation are also discussed. Variability recently observed in some bright disks promises to illuminate the evolution during the earliest phases when vapour condensates may be optically thick and acutely affected by the collision-point geometry. The outer reaches of planetary systems may also exhibit signatures of giant impacts, such as the clumpy debris structures seen around some stars.

  14. THE GEMINI NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF GIANT PLANETS AROUND YOUNG B AND A STARS

    SciTech Connect

    Nielsen, Eric L.; Liu, Michael C.; Chun, Mark; Ftaclas, Christ; Wahhaj, Zahed; Biller, Beth A.; Hayward, Thomas L.; Hartung, Markus; Alencar, Silvia H. P.; Artymowicz, Pawel; Boss, Alan; Clarke, Fraser; De Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane; Kuchner, Marc; Lin, Douglas N. C.; and others

    2013-10-10

    We have carried out high contrast imaging of 70 young, nearby B and A stars to search for brown dwarf and planetary companions as part of the Gemini NICI Planet-Finding Campaign. Our survey represents the largest, deepest survey for planets around high-mass stars (≈1.5-2.5 M{sub ☉}) conducted to date and includes the planet hosts β Pic and Fomalhaut. We obtained follow-up astrometry of all candidate companions within 400 AU projected separation for stars in uncrowded fields and identified new low-mass companions to HD 1160 and HIP 79797. We have found that the previously known young brown dwarf companion to HIP 79797 is itself a tight (3 AU) binary, composed of brown dwarfs with masses 58{sup +21}{sub -20} M{sub Jup} and 55{sup +20}{sub -19} M{sub Jup}, making this system one of the rare substellar binaries in orbit around a star. Considering the contrast limits of our NICI data and the fact that we did not detect any planets, we use high-fidelity Monte Carlo simulations to show that fewer than 20% of 2 M{sub ☉} stars can have giant planets greater than 4 M{sub Jup} between 59 and 460 AU at 95% confidence, and fewer than 10% of these stars can have a planet more massive than 10 M{sub Jup} between 38 and 650 AU. Overall, we find that large-separation giant planets are not common around B and A stars: fewer than 10% of B and A stars can have an analog to the HR 8799 b (7 M{sub Jup}, 68 AU) planet at 95% confidence. We also describe a new Bayesian technique for determining the ages of field B and A stars from photometry and theoretical isochrones. Our method produces more plausible ages for high-mass stars than previous age-dating techniques, which tend to underestimate stellar ages and their uncertainties.

  15. STATISTICAL STUDY OF THE EARLY SOLAR SYSTEM'S INSTABILITY WITH FOUR, FIVE, AND SIX GIANT PLANETS

    SciTech Connect

    Nesvorny, David; Morbidelli, Alessandro

    2012-10-01

    Several properties of the solar system, including the wide radial spacing and orbital eccentricities of giant planets, can be explained if the early solar system evolved through a dynamical instability followed by migration of planets in the planetesimal disk. Here we report the results of a statistical study, in which we performed nearly 10{sup 4} numerical simulations of planetary instability starting from hundreds of different initial conditions. We found that the dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, leading to ejection of at least one ice giant from the solar system. Planet ejection can be avoided if the mass of the transplanetary disk of planetesimals was large (M{sub disk} {approx}> 50 M{sub Earth}), but we found that a massive disk would lead to excessive dynamical damping (e.g., final e{sub 55} {approx}< 0.01 compared to present e{sub 55} = 0.044, where e{sub 55} is the amplitude of the fifth eccentric mode in the Jupiter's orbit), and to smooth migration that violates constraints from the survival of the terrestrial planets. Better results were obtained when the solar system was assumed to have five giant planets initially, and one ice giant, with mass comparable to that of Uranus and Neptune, was ejected into interstellar space by Jupiter. The best results were obtained when the ejected planet was placed into the external 3:2 or 4:3 resonance with Saturn and M{sub disk} {approx_equal} 20 M{sub Earth}. The range of possible outcomes is rather broad in this case, indicating that the present solar system is neither a typical nor expected result for a given initial state, and occurs, in best cases, with only a {approx_equal}5% probability (as defined by the success criteria described in the main text). The case with six giant planets shows interesting dynamics but does offer significant advantages relative to the five-planet case.

  16. Mass Estimates of a Giant Planet in a Protoplanetary Disk from the Gap Structures

    NASA Astrophysics Data System (ADS)

    Kanagawa, Kazuhiro D.; Muto, Takayuki; Tanaka, Hidekazu; Tanigawa, Takayuki; Takeuchi, Taku; Tsukagoshi, Takashi; Momose, Munetake

    2015-06-01

    A giant planet embedded in a protoplanetary disk forms a gap. An analytic relationship among the gap depth, planet mass Mp, disk aspect ratio hp, and viscosity α has been found recently, and the gap depth can be written in terms of a single parameter K={{({{M}p}/{{M}*})}2}hp-5{{α }-1}. We discuss how observed gap features can be used to constrain the disk and/or planet parameters based on the analytic formula for the gap depth. The constraint on the disk aspect ratio is critical in determining the planet mass so the combination of the observations of the temperature and the image can provide a constraint on the planet mass. We apply the formula for the gap depth to observations of HL Tau and HD 169142. In the case of HL Tau, we propose that a planet with ≳ 0.3 MJ is responsible for the observed gap at 30 AU from the central star based on the estimate that the gap depth is ≲ 1/3. In the case of HD 169142, the planet mass that causes the gap structure recently found by VLA is ≳ 0.4{{M}J}. We also argue that the spiral structure, if observed, can be used to estimate the lower limit of the disk aspect ratio and the planet mass.

  17. On the minimum core mass for giant planet formation at wide separations

    SciTech Connect

    Piso, Ana-Maria A.; Youdin, Andrew N.

    2014-05-01

    In the core accretion hypothesis, giant planets form by gas accretion onto solid protoplanetary cores. The minimum (or critical) core mass to form a gas giant is typically quoted as 10 M {sub ⊕}. The actual value depends on several factors: the location in the protoplanetary disk, atmospheric opacity, and the accretion rate of solids. Motivated by ongoing direct imaging searches for giant planets, this study investigates core mass requirements in the outer disk. To determine the fastest allowed rates of gas accretion, we consider solid cores that no longer accrete planetesimals, as this would heat the gaseous envelope. Our spherical, two-layer atmospheric cooling model includes an inner convective region and an outer radiative zone that matches onto the disk. We determine the minimum core mass for a giant planet to form within a typical disk lifetime of 3 Myr. The minimum core mass declines with disk radius, from ∼8.5 M {sub ⊕} at 5 AU to ∼3.5 M {sub ⊕} at 100 AU, with standard interstellar grain opacities. Lower temperatures in the outer disk explain this trend, while variations in disk density are less influential. At all distances, a lower dust opacity or higher mean molecular weight reduces the critical core mass. Our non-self-gravitating, analytic cooling model reveals that self-gravity significantly affects early atmospheric evolution, starting when the atmosphere is only ∼10% as massive as the core.

  18. Forming Giant Planet Cores by Pebble Accretion -- Why Slow and Steady wins the Race

    NASA Astrophysics Data System (ADS)

    Kretke, Katherine A.; Levison, Harold F.

    2014-05-01

    In recent years there has been a radical new solution proposed to solve the problem of giant planet core formation. "Pebbles", particles ranging from centimeters to meters in size, have been shown to accrete extremely efficiently due to aerodynamic drag. Large capture cross-sections combined with fast pebble drift rates can allow a single planetesimal to grow from Ceres size to 10s of Earth masses well within the lifetime of gaseous circumstellar disks. However, at large sizes, the the capture-cross section of pebbles goes with the Hill sphere, forcing pebble accretion to becomes a fundamentally "oligarchic-like" process. This makes it difficult to form a few giant planet cores; instead a more generic result is many 10s to 100s of competing oligarchs. In this work, we present a way to get around this oligarchic dilemma If pebbles are assumed to form slowly over a long period of time, then the planetesimal growth rates are slow enough for the planetesimals to dynamically excite each other. As the larger planetisimals/proto-planets stir their smaller companions, these smaller bodies are excited to such a degree that they spend only a small fraction of their orbits embedded in the cooler pebble disk. This allows the larger bodies to starve their neighbors and maintain a relative runaway growth rate to high mass, effectively forming the cores of giant planets.

  19. All in the Family: What Brown Dwarfs Teach Us About Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Marley, M.

    2003-01-01

    As we await the first direct image of an extrasolar giant planet, we can turn to theory and the experience gained in the campaign to detect and understand brown dwarfs for guidance on what to expect. As with any new arrival to a family, there should be a strong family resemblance (one hopes) along with notable unique features and interesting peculiarities. The 300 or so known L and T dwarfs, combined with our own giant planets, already span much of the effective temperature range within which extrasolar planets will be found. Only objects with thick, easily detectable, water clouds have yet to be seen. Thus we already know much of the family. I will describe what we have learned from studying these objects, focusing on the important roles clouds and atmospheric chemistry play in affecting their atmospheres and emergent spectra. Relying on these findings and theoretical models, I'll sketch out what we can expect from extrasolar giant planets, focusing on easily detectable features. Some wild cards, of course, are to be expected. Photochemical hazes, in particular, may obscure the family traits on the faces of Jupiter's distant cousins and may make one wonder, at least momentarily, about the milkman.

  20. Temperature changes and energy inputs in giant planet atmospheres: what we are learning from H3+.

    PubMed

    Stallard, Tom S; Melin, Henrik; Miller, Steve; O'Donoghue, James; Cowley, Stan W H; Badman, Sarah V; Adriani, Alberto; Brown, Robert H; Baines, Kevin H

    2012-11-13

    Since its discovery at Jupiter in 1988, emission from H(3)(+) has been used as a valuable diagnostic tool in our understanding of the upper atmospheres of the giant planets. One of the lasting questions we have about the giant planets is why the measured upper atmosphere temperatures are always consistently hotter than the temperatures expected from solar heating alone. Here, we describe how H(3)(+) forms across each of the planetary disks of Jupiter, Saturn and Uranus, presenting the first observations of equatorial H(3)(+) at Saturn and the first profile of H(3)(+) emission at Uranus not significantly distorted by the effects of the Earth's atmosphere. We also review past observations of variations in temperature measured at Uranus and Jupiter over a wide variety of time scales. To this, we add new observations of temperature changes at Saturn, using observations by Cassini. We conclude that the causes of the significant level of thermal variability observed over all three planets is not only an important question in itself, but that explaining these variations could be the key to answering the more general question of why giant planet upper atmospheres are so hot. PMID:23028167

  1. Temperature changes and energy inputs in giant planet atmospheres: what we are learning from H3+.

    PubMed

    Stallard, Tom S; Melin, Henrik; Miller, Steve; O'Donoghue, James; Cowley, Stan W H; Badman, Sarah V; Adriani, Alberto; Brown, Robert H; Baines, Kevin H

    2012-11-13

    Since its discovery at Jupiter in 1988, emission from H(3)(+) has been used as a valuable diagnostic tool in our understanding of the upper atmospheres of the giant planets. One of the lasting questions we have about the giant planets is why the measured upper atmosphere temperatures are always consistently hotter than the temperatures expected from solar heating alone. Here, we describe how H(3)(+) forms across each of the planetary disks of Jupiter, Saturn and Uranus, presenting the first observations of equatorial H(3)(+) at Saturn and the first profile of H(3)(+) emission at Uranus not significantly distorted by the effects of the Earth's atmosphere. We also review past observations of variations in temperature measured at Uranus and Jupiter over a wide variety of time scales. To this, we add new observations of temperature changes at Saturn, using observations by Cassini. We conclude that the causes of the significant level of thermal variability observed over all three planets is not only an important question in itself, but that explaining these variations could be the key to answering the more general question of why giant planet upper atmospheres are so hot.

  2. More ESSs with the ELTs: Gas Giants, Habitable Planets and Exomoons

    NASA Astrophysics Data System (ADS)

    Marois, Christian

    2015-12-01

    The upcoming 30-m class telescopes will open-up exciting science capabilities, achieving three times better angular resolution, allowing for of wealth of new discoveries to be made of closer in/lower mass planets. While the discovery of young gas giant planets in nearby systems will become daily news with these telescopes, we can expect the Quest for the first picture/characterization of an Earth-like planet to be at its apogee in the 2020s, with the development of dedicated instruments in the NIR and thermal IR for the ELTs; in parallel with space endeavors. Third generation ExAO systems will produce higher SNR planet images of known systems, allowing, for the first time, an in-depth analysis of these worlds, including their surface mapping, and possibly revealing the presence of exomoons.

  3. Extrasolar Giant Planet in Earth-like Orbit

    NASA Astrophysics Data System (ADS)

    1999-07-01

    Discovery from a Long-term Project at La Silla A new extrasolar planet has been found at the ESO La Silla Observatory as a companion to iota Horologii (iota Hor) . This 5.4-mag solar-type star is located at a distance of 56 light-years and is just visible to the unaided eye in the southern constellation Horologium (The Pendulum Clock). The discovery is the result of a long-term survey of forty solar-type stars that was begun in November 1992. It is based on highly accurate measurements of stellar radial velocities, i.e. the speed with which a star moves along the line of sight. The presence of a planet in orbit around a star is inferred from observed, regular changes of this velocity, as the host star and its planet revolve around a common center of gravity. Since in all cases the star is much heavier than the planet, the resulting velocity variations of the star are always quite small. The team that found the new planet, now designated iota Hor b , consists of Martin Kürster , Michael Endl and Sebastian Els (ESO-Chile), Artie P. Hatzes and William D. Cochran (University of Texas, Austin, USA), and Stefan Döbereiner and Konrad Dennerl (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany). Iodine cell provides very accurate velocity measurements iota Hor b represents the first discovery of an extrasolar planet with an ESO instrument [1]. The finding is based on data obtained with ESO's highest-resolution spectrograph, the Coudé Echelle Spectrometer (CES) at the 1.4-m Coudé Auxiliary Telescope (CAT). While this telescope has recently been decommissioned, the CES instrument is now coupled via an optical fiber link to the larger ESO 3.6-m telescope, thus permitting the continuation of this survey. The high precision radial velocity measurements that are necessary for a study of this type were achieved by means of a special calibration technique. It incorporates an iodine gas absorption cell and sophisticated data modelling. The cell is used like

  4. From planetesimals to terrestrial planets: N-body simulations including the effects of nebular gas and giant planets

    NASA Astrophysics Data System (ADS)

    Morishima, Ryuji; Stadel, Joachim; Moore, Ben

    2010-06-01

    We present results from a suite of N-body simulations that follow the formation and accretion history of the terrestrial planets using a new parallel treecode that we have developed. We initially place 2000 equal size planetesimals between 0.5 and 4.0 AU and the collisional growth is followed until the completion of planetary accretion (>100 Myr). A total of 64 simulations were carried out to explore sensitivity to the key parameters and initial conditions. All the important effect of gas in laminar disks are taken into account: the aerodynamic gas drag, the disk-planet interaction including Type I migration, and the global disk potential which causes inward migration of secular resonances as the gas dissipates. We vary the initial total mass and spatial distribution of the planetesimals, the time scale of dissipation of nebular gas (which dissipates uniformly in space and exponentially in time), and orbits of Jupiter and Saturn. We end up with 1-5 planets in the terrestrial region. In order to maintain sufficient mass in this region in the presence of Type I migration, the time scale of gas dissipation needs to be 1-2 Myr. The final configurations and collisional histories strongly depend on the orbital eccentricity of Jupiter. If today's eccentricity of Jupiter is used, then most of bodies in the asteroidal region are swept up within the terrestrial region owing to the inward migration of the secular resonance, and giant impacts between protoplanets occur most commonly around 10 Myr. If the orbital eccentricity of Jupiter is close to zero, as suggested in the Nice model, the effect of the secular resonance is negligible and a large amount of mass stays for a long period of time in the asteroidal region. With a circular orbit for Jupiter, giant impacts usually occur around 100 Myr, consistent with the accretion time scale indicated from isotope records. However, we inevitably have an Earth size planet at around 2 AU in this case. It is very difficult to obtain

  5. Circum-planetary discs as bottlenecks for gas accretion onto giant planets

    NASA Astrophysics Data System (ADS)

    Rivier, G.; Crida, A.; Morbidelli, A.; Brouet, Y.

    2012-12-01

    Context. With hundreds of exoplanets detected, it is necessary to revisit giant planets accretion models to explain their mass distribution. In particular, formation of sub-jovian planets remains unclear, given the short timescale for the runaway accretion of massive atmospheres. However, gas needs to pass through a circum-planetary disc. If the latter has a low viscosity (as expected if planets form in "dead zones"), it might act as a bottleneck for gas accretion. Aims: We investigate what the minimum accretion rate is for a planet under the limit assumption that the circum-planetary disc is totally inviscid, and the transport of angular momentum occurs solely because of the gravitational perturbations from the star. Methods: To estimate the accretion rate, we present a steady-state model of an inviscid circum-planetary disc, with vertical gas inflow and external torque from the star. Hydrodynamical simulations of a circum-planetary disc were conducted in 2D, in a planetocentric frame, with the star as an external perturber in order to measure the torque exerted by the star on the disc. Results: The disc shows a two-armed spiral wave caused by stellar tides, propagating all the way in from the outer edge of the disc towards the planet. The stellar torque is small and corresponds to a doubling time for a Jupiter mass planet of the order of 5 Myr. Given the limit assumptions, this is clearly a lower bound of the real accretion rate. Conclusions: This result shows that gas accretion onto a giant planet can be regulated by circum-planetary discs. This suggests that the diversity of masses of extra-solar planets may be the result of different viscosities in these discs.

  6. The detectability of extrasolar terrestrial and giant planets during their luminous final accretion

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1994-01-01

    One of the outstanding scienfific questions in astronomy is the frequency at which solar systems form. Answering this question is an observational challenge because extrasolar planets are intrinsically difficult to directly detect. Here I examine the direct detectability of planets during the short but unique epoch of giant impacts that is a hallmark of the standard theory of planetary formation. Sufficiently large impacts during this era are capable of creating a luminous, 1500-2500 K photosphere, which can persist for time scales exceeding 10(exp 3) yr in some cases. I examine the detectability of such events and the number of young stars one would need to examine to expect to find a luminous terrestrial-class planet after a giant impact. With emerging IR interferometric technology, thermally luminous Earth-sized objects can be detected in nearby star forming regions in 1-2 nights of observing time. Unfortunately, predictions indicated that approximately 250 young stars would have to be searched to expect to find one hot, terrestrial-sized planet. By comparison, the detection of Saturn and Uranus-Neptune-sized planets after a giant impact requires only 1-2 h of observing time. A single Keck-class telescope should be able to determine whether such planets are common in the nearest star forming regions by examining less than or approximately equal to 100 young stars over a few tens of nights. The results obtained here suggest a new strategy for the detection of solar systems with the potential for the observational confirmation of the standard theory of late-stage planetary accretion.

  7. The detectability of extrasolar terrestrial and giant planets during their luminous final accretion

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1994-01-01

    One of the outstanding scientific questions in astronomy is the frequency at which solar systems form. Answering this question is an observational challenge because extrasolar planets are intrinsically difficult to directly detect. The direct detectability of planets is examined during the short but unique epoch of giant impacts that is a hallmark of the standard theory of planetary formation. Sufficiently large impacts during this era are capable of creating a luminous, 1500-2500 K photosphere, which can persist for timescales exceeding 103 years in some cases. The detectability of such events and the number of young stars one would need to examine to expect to find a luminous terrestrial class planet after a giant impact are examined. With emerging IR interferometric technology, thermally-luminous earth-sized objects can be detected in nearby star forming regions in 1-2 nights observing time. Unfortunately, predictions indicate that approximately 250 young stars would have to be searched to expect to find one hot, terrestrial-sized planet. By comparison, the detection of Saturn and Uranus/Neptune-sized planets after a giant impact requires only 1-2 hours of observing time. A single Keck-class telescope should be able to determine whether such planets are common in the nearest star forming regions by examining about less than 100 young stars over a few tens of nights. The results obtained herein suggest a new strategy for the detection of solar systems with the potential for the observational confirmation of the standard theory of late-stage planetary accretion.

  8. Formation and Early Evolution of Solar and Extra-Solar Giant Planets

    NASA Technical Reports Server (NTRS)

    Bodenheimer, P. H.; Hubickyj, Olenka; Boyce, Joseph (Technical Monitor)

    2001-01-01

    This project investigates the origin of giant planets, both in the Solar System and around other stars. It is assumed that the planets form by the core accretion process: small solid particles in a disk surrounding a young star gradually coagulate into objects of a few kilometers in size, known as planetesimals, which then accumulate into solid protoplanetary cores. Once the cores have become large enough, they are able to attract gas from the surrounding disk to form the deep gaseous envelope of the giant planet. Our code simulates giant planet growth in a spherical approximation, and it has been quite successful in addressing a number of basic planetary properties. Further improvements to the code have been made to achieve a more realistic understanding of planetary formation. The computations of the models were based on an earlier version of our code and were stopped at the onset of runaway gas accretion. Now, improved boundary conditions have been incorporated into the code to allow for hydrodynamic inflow of gas and to handle the late stages of evolution when the planet evolves at constant mass. These changes were made to the version of the code that uses a constant accretion rate and to the version that uses a self-consistent method for calculating both the solid and gas accretion rates. The equation of state has been updated to incorporate the detailed tables of Saumon, Chabrier, and Van Horn. The opacities were updated to include the results of Alexander and Ferguson. The outer boundary conditions were modified. During the accretion phase when the planet's radius is between the accretion radius and the tidal radius, we set the outer boundary at a 'modified' accretion radius, which is the point where thermal energy is enough to bring gas to the edge of the Hill sphere.

  9. Final Masses of Giant Planets II: Jupiter Formation in a Gas-Depleted Disk

    NASA Astrophysics Data System (ADS)

    Tanigawa, Takayuki; Tanaka, Hidekazu

    2015-12-01

    Firstly, we study the final masses of giant planets growing in protoplanetary disks through capture of disk gas, by employing an empirical formula for the gas capture rate and a shallow disk gap model, which are both based on hydrodynamical simulations. The shallow disk gaps cannot terminate growth of giant planets. For planets less massive than 10 Jupiter masses, their growth rates are mainly controlled by the gas supply through the global disk accretion, rather than their gaps. The insufficient gas supply compared with the rapid gas capture causes a depletion of the gas surface density even at the outside of the gap, which can create an inner hole in the protoplanetary disk. Our model can also predict how deep the inner hole is for a given planet mass. Secondly, our findings are applied to the formation of our solar system. For the formation of Jupiter, a very low-mass gas disk with a few or several Jupiter masses is required at the beginning of its gas capture because of the non-stopping capture. Such a low-mass gas disk with sufficient solid material can be formed through viscous evolution from an initially ˜10AU-sized compact disk with the solar composition. By the viscous evolution with a moderate viscosity of α˜10-3, most of disk gas accretes onto the sun and a widely spread low-mass gas disk remains when the solid core of Jupiter starts gas capture at t˜107 yrs. The depletion of the disk gas is suitable for explaining the high metallicity in giant planets of our solar system. A very low-mass gas disk also provides a plausible path where type I and II planetary migrations are both suppressed significantly. In particular, we also show that the type II migration of Jupiter-size planets becomes inefficient because of the additional gas depletion due to the rapid gas capture by themselves.

  10. On the growth and orbital evolution of giant planets in layered protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Pierens, A.; Nelson, R. P.

    2010-09-01

    Aims: We present the results of hydrodynamic simulations of the growth and orbital evolution of giant planets embedded in a protoplanetary disk with a dead-zone. The aim is to examine to what extent the presence of a dead-zone affects the rates of mass accretion and migration for giant planets. Methods: We performed 3D numerical simulations using a grid-based hydrodynamics code. In these simulations of laminar, non-magnetised disks, the dead-zone is treated as a region where the vertical profile of the viscosity depends on the distance from the equatorial plane. We consider dead-zones with vertical sizes, HDZ, ranging from 0 to HDZ = 2.3 H, where H is the disk scale-height. For all models, the vertically integrated viscous stress, and the related mass flux through the disk, have the same value (equivalent to 10-8 M⊙ yr-1), such that the simulations test the dependence of planetary mass accretion and migration on the vertical distribution of the viscous stress (and mass flux). For each model, an embedded 30 M_⊕ planet on a fixed circular orbit is allowed to accrete gas from the disk. Once the planet mass becomes equal to that of Saturn or Jupiter, we allow the planet orbit to evolve due to gravitational interaction with the disk. Results: We find that the time scale over which a protoplanet grows to become a giant planet is essentially independent of the dead-zone size, and depends only on the total rate at which the disk viscously supplies material to the planet. For Saturn-mass planets, the migration rate depends only weakly on the size of the dead-zone for HDZ ≤ 1.5 H, but becomes noticeably slower when HDZ = 2.3 H. This effect is apparently due to the desaturation of corotation torques which originate from residual material in the partial-gap region. For Jupiter-mass planets, there is a clear tendency for the migration to proceed more slowly as the size of the dead-zone increases, with migration rates differing by approximately 40% for models with HDZ = 0

  11. Runaway greenhouse effect on exomoons due to irradiation from hot, young giant planets

    NASA Astrophysics Data System (ADS)

    Heller, R.; Barnes, R.

    2015-04-01

    The Kepler space telescope has proven capable of detecting transits of objects almost as small as the Earth's Moon. Some studies suggest that moons as small as 0.2 Earth masses can be detected in the Kepler data by transit timing variations and transit duration variations of their host planets. If such massive moons exist around giant planets in the stellar habitable zone (HZ), then they could serve as habitats for extraterrestrial life. While earlier studies on exomoon habitability assumed the host planet to be in thermal equilibrium with the absorbed stellar flux, we here extend this concept by including the planetary luminosity from evolutionary shrinking. Our aim is to assess the danger of exomoons to be in a runaway greenhouse state due to extensive heating from the planet. We apply pre-computed evolution tracks for giant planets to calculate the incident planetary radiation on the moon as a function of time. Added to the stellar flux, the total illumination yields constraints on a moon's habitability. Ultimately, we include tidal heating to evaluate a moon's energy budget. We use a semi-analytical formula to parameterize the critical flux for the moon to experience a runaway greenhouse effect. Planetary illumination from a 13-Jupiter-mass planet onto an Earth-sized moon at a distance of ten Jupiter radii can drive a runaway greenhouse state on the moon for about 200 million years (Myr). When stellar illumination equivalent to that received by Earth from the Sun is added, then the runaway greenhouse holds for about 500 Myr. After 1000 Myr, the planet's habitable edge has moved inward to about six Jupiter radii. Exomoons in orbits with eccentricities of 0.1 experience strong tidal heating; they must orbit a 13-Jupiter-mass host beyond 29 or 18 Jupiter radii after 100 Myr (at the inner and outer boundaries of the stellar HZ, respectively), and beyond 13 Jupiter radii (in both cases) after 1000 Myr to be habitable. If a roughly Earth-sized, Earth-mass moon would

  12. Formation of giant planets by fragmentation of protoplanetary disks.

    PubMed

    Mayer, Lucio; Quinn, Thomas; Wadsley, James; Stadel, Joachim

    2002-11-29

    The evolution of gravitationally unstable protoplanetary gaseous disks has been studied with the use of three-dimensional smoothed particle hydrodynamics simulations with unprecedented resolution. We have considered disks with initial masses and temperature profiles consistent with those inferred for the protosolar nebula and for other protoplanetary disks. We show that long-lasting, self-gravitating protoplanets arise after a few disk orbital periods if cooling is efficient enough to maintain the temperature close to 50 K. The resulting bodies have masses and orbital eccentricities similar to those of detected extrasolar planets.

  13. DETECTION OF A GIANT EXTRASOLAR PLANET ORBITING THE ECLIPSING POLAR DP LEO

    SciTech Connect

    Qian, S.-B.; Liao, W.-P.; Zhu, L.-Y.; Dai, Z.-B.

    2010-01-01

    DP Leo is the first discovered eclipsing polar with a short period of 1.4967 hours. The period variation of the eclipsing binary was analyzed by using five new determined eclipse times together with those compiled from the literature. It is discovered that the O - C curve of DP Leo shows a cyclic variation with a period of 23.8 years and a semiamplitude of 31.5 s. The small-amplitude periodic change can be plausibly explained as the light-travel time effect due to the presence of a tertiary companion. The mass of the tertiary component is determined to be M {sub 3}sin i' = 0.00600({+-}0.00055) M {sub sun} = 6.28({+-}0.58) M {sub Jupiter} when a total mass of 0.69 M {sub sun} is adopted. If the tertiary companion is coplanar to the eclipsing binary (i.e., i' = 79.{sup 0}5), it should be a giant extrasolar planet with a mass of 6.39 M {sub Jupiter} at a distance of 8.6 astronomical units to the central binary. One of the most interesting things that we have learned about extrasolar planets over the last 17 years is that they can exist almost anywhere. The detection of a giant planet orbiting a polar would provide insight into the formation and evolution of circumbinary planets (planets orbiting both components of short-period binaries) as well as the late evolution of binary stars.

  14. Occurrence of giant impacts during the growth of the terrestrial planets.

    PubMed

    Wetherill, G W

    1985-05-17

    Three-dimensional Monte Carlo simulations of the accumulation of the terrestrial planets in the absence of gas drag produced results that are in general agreement with the number and distribution of the present planets. The accumulation process appears to be characterized by impact of bodies as large as three times the mass of Mars at velocities of about 9 kilometers per second. These giant impacts on Earth may have supplied the material and angular momentum that formed the moon, should have heated Earth to the melting point, and may have been responsible for the differences in the content of inert gases of the atmospheres of Earth and Venus.

  15. NH4SH and cloud cover in the atmospheres of the giant planets

    NASA Astrophysics Data System (ADS)

    Ibragimov, K. Iu.; Solodovnik, A. A.

    1991-02-01

    The probability of the formation of NH4SH and (NH4)2S is examined on the basis of the Le Chatelier principle. It is shown that it is very doubtful if NH4SH can be created in the atmospheres of the giant planets in quantities sufficient for cloud formation. Thus (NH4)2S is considered as a more likely candidate for cloud formation in the atmospheres of these planets, inasmuch as the conditions for its production there are more favorable.

  16. A stability limit for the atmospheres of giant extrasolar planets.

    PubMed

    Koskinen, Tommi T; Aylward, Alan D; Miller, Steve

    2007-12-01

    Recent observations of the planet HD209458b indicate that it is surrounded by an expanded atmosphere of atomic hydrogen that is escaping hydrodynamically. Theoretically, it has been shown that such escape is possible at least inside an orbit of 0.1 au (refs 4 and 5), and also that H3+ ions play a crucial role in cooling the upper atmosphere. Jupiter's atmosphere is stable, so somewhere between 5 and 0.1 au there must be a crossover between stability and instability. Here we show that there is a sharp breakdown in atmospheric stability between 0.14 and 0.16 au for a Jupiter-like planet orbiting a solar-type star. These results are in contrast to earlier modelling that implied much higher thermospheric temperatures and more significant evaporation farther from the star. (We use a three-dimensional, time-dependent coupled thermosphere-ionosphere model and properly include cooling by H3+ ions, allowing us to model globally the redistribution of heat and changes in molecular composition.) Between 0.2 and 0.16 au cooling by H3+ ions balances heating by the star, but inside 0.16 au molecular hydrogen dissociates thermally, suppressing the formation of H3+ and effectively shutting down that mode of cooling. PMID:18064005

  17. A Cloud Microphysics Model for the Gas Giant Planets

    NASA Astrophysics Data System (ADS)

    Palotai, Csaba J.; Le Beau, Raymond P.; Shankar, Ramanakumar; Flom, Abigail; Lashley, Jacob; McCabe, Tyler

    2016-10-01

    Recent studies have significantly increased the quality and the number of observed meteorological features on the jovian planets, revealing banded cloud structures and discrete features. Our current understanding of the formation and decay of those clouds also defines the conceptual modes about the underlying atmospheric dynamics. The full interpretation of the new observational data set and the related theories requires modeling these features in a general circulation model (GCM). Here, we present details of our bulk cloud microphysics model that was designed to simulate clouds in the Explicit Planetary Hybrid-Isentropic Coordinate (EPIC) GCM for the jovian planets. The cloud module includes hydrological cycles for each condensable species that consist of interactive vapor, cloud and precipitation phases and it also accounts for latent heating and cooling throughout the transfer processes (Palotai and Dowling, 2008. Icarus, 194, 303–326). Previously, the self-organizing clouds in our simulations successfully reproduced the vertical and horizontal ammonia cloud structure in the vicinity of Jupiter's Great Red Spot and Oval BA (Palotai et al. 2014, Icarus, 232, 141–156). In our recent work, we extended this model to include water clouds on Jupiter and Saturn, ammonia clouds on Saturn, and methane clouds on Uranus and Neptune. Details of our cloud parameterization scheme, our initial results and their comparison with observations will be shown. The latest version of EPIC model is available as open source software from NASA's PDS Atmospheres Node.

  18. A stability limit for the atmospheres of giant extrasolar planets.

    PubMed

    Koskinen, Tommi T; Aylward, Alan D; Miller, Steve

    2007-12-01

    Recent observations of the planet HD209458b indicate that it is surrounded by an expanded atmosphere of atomic hydrogen that is escaping hydrodynamically. Theoretically, it has been shown that such escape is possible at least inside an orbit of 0.1 au (refs 4 and 5), and also that H3+ ions play a crucial role in cooling the upper atmosphere. Jupiter's atmosphere is stable, so somewhere between 5 and 0.1 au there must be a crossover between stability and instability. Here we show that there is a sharp breakdown in atmospheric stability between 0.14 and 0.16 au for a Jupiter-like planet orbiting a solar-type star. These results are in contrast to earlier modelling that implied much higher thermospheric temperatures and more significant evaporation farther from the star. (We use a three-dimensional, time-dependent coupled thermosphere-ionosphere model and properly include cooling by H3+ ions, allowing us to model globally the redistribution of heat and changes in molecular composition.) Between 0.2 and 0.16 au cooling by H3+ ions balances heating by the star, but inside 0.16 au molecular hydrogen dissociates thermally, suppressing the formation of H3+ and effectively shutting down that mode of cooling.

  19. THE ANGLO-AUSTRALIAN PLANET SEARCH. XX. A SOLITARY ICE-GIANT PLANET ORBITING HD 102365

    SciTech Connect

    Tinney, C. G.; Wittenmyer, Robert A.; Bailey, Jeremy; Butler, R. Paul; Jones, Hugh R. A.; O'Toole, Simon; Carter, Brad D.

    2011-02-01

    We present 12 years of precision Doppler data for the very nearby G3 star HD 102365, which reveals the presence of a Neptune-like planet with a 16.0 M{sub Earth} minimum mass in a 122.1 day orbit. Very few 'Super Earth' planets have been discovered to date in orbits this large and those that have been found reside in multiple systems of between three and six planets. HD 102365 b, in contrast, appears to orbit its star in splendid isolation. Analysis of the residuals to our Keplerian fit for HD 102365 b indicates that there are no other planets with minimum mass above 0.3 M{sub Jup} orbiting within 5 AU and no other 'Super Earths' more massive than 10 M{sub Earth} orbiting at periods shorter than 50 days. At periods of less than 20 days these limits drop to as low as 6 M{sub Earth}. There are now 32 exoplanets known with minimum mass below 20 M{sub Earth}, and interestingly the period distributions of these low-mass planets seem to be similar whether they orbit M-, K-, or G-type dwarfs.

  20. Internal structures and compositions of giant (exo)planets

    NASA Astrophysics Data System (ADS)

    Guillot, Tristan; Parmentier, Vivien; Havel, Mathieu

    2015-12-01

    One can now attempt to determine the abundances of key species in the atmospheres of exoplanets, in particular hot Jupiters. In parallel, the knowledge of the densities of these exoplanets informs us on their bulk composition in terms of amounts of dense material (rocks and ices) compared to light ones (hydrogen and helium). Linking these constraints seems natural and, intuitively, one would expect dense planets to contain more heavy elements in their atmospheres. However, several physical processes, in particular the formation of a central core, its gradual erosion and the growth of a deep outer radiative zone, could decouple partially or even completely interior and atmospheric composition. The latter will also depend on how heavy elements were delivered to the planet.Close to us, measurements performed in the atmosphere of Jupiter (and to some extent in Saturn) already provide us with important clues: The high enrichment in carbon coupled to a more modest but significant enrichment in noble gases indicates that solids and gas-species followed different routes. Jupiter obtained its solids probably as a core and via pebble accretion and captured disk gas that had lost part of its hydrogen and helium. The elements originally solid in the disk but fluid in the planetary interior were at least partially mixed upward to account for the present day atmospheric composition.This simple scenario can be tested. The comparison of bulk and atmospheric compositions of hot Jupiters of different masses will tell us the importance of mixing. Measurements by the Juno spacecraft at Jupiter starting in July 2016 will help us constrain the abundance of water, a key element to understand how the solids were captured.

  1. Accretional origin of the giant planets and its consequences

    NASA Astrophysics Data System (ADS)

    Ip, Wing-Huen; Fernández, Julio A.

    The basic mass distribution and orbital structure of the solar system are determined by the original mass and angular momentum of the solar nebula and planetary accretion effect. Dust-gas aerodynamic interaction in the gaseous solar nebula could lead to the formation of an outer boundary or edge of the condensed matter in the outer planetary region. Such inward drift of the small solid bodies was subsequently reversed by the angular momentum transfer effect associated with the collisional accretion process. The orbits of Neptune and Uranus were found to expand outward during the accretional phase in numerical simulations. Such orbital migration mechanism might have played a key role at the same time in capturing Pluto into its 3:2 resonance with Neptune and the trapping of a significant number of Kuiper belt objects in this resonance. Gravitational scattering of icy planetesimals by the growing proto-Uranus and, most importantly, proto-Neptune was very effective in planting comets in the distant Oort cloud reservoir and driving the heavy bombardment event of the terrestrial planets and the Kuiper belt objects. To some extent the quasi-resonant relation of the major planets might have also been influenced by the orbital migration process. Besides gravitational scattering and accumulation of small planetesimals there is evidence that the protoplanets had collided with large planetoids of Mars- to Earth-size. The formation of an extended gaseous envelope/disk after the megaimpact event could be important in reprocessing the isotope (i.e., D/H) ratio of the cometary material. This might provide a possible explanation to the unexpected difference between the D/H ratio in the water ice of comets (with an enrichment factor of f ≍ 10 in comparison with the interstellar value) and those in the cores of Uranus and Neptune (with f ≍ 3).

  2. THEY MIGHT BE GIANTS: LUMINOSITY CLASS, PLANET OCCURRENCE, AND PLANET-METALLICITY RELATION OF THE COOLEST KEPLER TARGET STARS

    SciTech Connect

    Mann, Andrew W.; Hilton, Eric J.; Gaidos, Eric; Lepine, Sebastien

    2012-07-01

    We estimate the stellar parameters of late K- and early M-type Kepler target stars. We obtain medium-resolution visible spectra of 382 stars with K{sub P} - J > 2 ({approx_equal}K5 and later spectral type). We determine luminosity class by comparing the strength of gravity-sensitive indices (CaH, K I, Ca II, and Na I) to their strength in a sample of stars of known luminosity class. We find that giants constitute 96% {+-} 1% of the bright (K{sub P} < 14) Kepler target stars, and 7% {+-} 3% of dim (K{sub P} > 14) stars, significantly higher than fractions based on the stellar parameters quoted in the Kepler Input Catalog (KIC). The KIC effective temperatures are systematically (110{sup +15}{sub -35} K) higher than temperatures we determine from fitting our spectra to PHOENIX stellar models. Through Monte Carlo simulations of the Kepler exoplanet candidate population, we find a planet occurrence of 0.36 {+-} 0.08 when giant stars are properly removed, somewhat higher than when a KIC log g > 4 criterion is used (0.27 {+-} 0.05). Last, we show that there is no significant difference in g - r color (a probe of metallicity) between late-type Kepler stars with transiting Earth-to-Neptune-size exoplanet candidates and dwarf stars with no detected transits. We show that a previous claimed offset between these two populations is most likely an artifact of including a large number of misidentified giants.

  3. SHOCKS AND A GIANT PLANET IN THE DISK ORBITING BP PISCIUM?

    SciTech Connect

    Melis, C.; Zuckerman, B.; Gielen, C.; Chen, C. H.; Rhee, Joseph H.; Song, Inseok

    2010-11-20

    Spitzer Infrared Spectrograph data support the interpretation that BP Piscium, a gas and dust enshrouded star residing at high Galactic latitude, is a first-ascent giant rather than a classical T Tauri star. Our analysis suggests that BP Piscium's spectral energy distribution can be modeled as a disk with a gap that is opened by a giant planet. Modeling the rich mid-infrared emission line spectrum indicates that the solid-state emitting grains orbiting BP Piscium are primarily composed of {approx}75 K crystalline, magnesium-rich olivine; {approx}75 K crystalline, magnesium-rich pyroxene; {approx}200 K amorphous, magnesium-rich pyroxene; and {approx}200 K annealed silica (cristobalite). These dust grains are all sub-micron sized. The giant planet and gap model also naturally explains the location and mineralogy of the small dust grains in the disk. Disk shocks that result from disk-planet interaction generate the highly crystalline dust which is subsequently blown out of the disk mid-plane and into the disk atmosphere.

  4. Scaling Laws For Convection And Jet Speeds On Giant Planet Atmospheres

    NASA Astrophysics Data System (ADS)

    Kaspi, Yohai; Showman, A. P.; Flierl, G. R.

    2010-10-01

    Three dimensional studies of convection in deep spherical shells have been used to test the hypothesis that the strong jet streams on giant planets result from convection throughout the molecular envelopes. Due to computational limitations, these simulations must be performed at parameter settings far from Jovian values and generally adopt heat fluxes much larger than the planetary values. Several numerical investigations have identified trends for how the mean jet speed varies with heat flux and viscosity, but no previous theories have been advanced to explain these trends. Here, we show using simple arguments that if convective release of potential energy pumps the jets and viscosity damps them, the mean jet speeds split into different regimes depending on the strength of the convection. For each regime we provide a different scaling based on energy constraints, momentum constraints, and mixing length theory. Transitions between these regimes are predicted and are consistent with three-dimensional numerical experiments. Our scalings provide a good match to the mean jet speeds obtained in previous Boussinesq and anelastic, three-dimensional simulations of convection within giant planets over a broad range of parameters. When extrapolated to the real heat fluxes, these scalings suggest that the mass-weighted jet speeds in the molecular envelopes of the giant planets are much weaker, by an order of magnitude or more, than the jet speeds measured at cloud level.

  5. Inhibition of giant-planet formation by rapid gas depletion around young stars.

    PubMed

    Zuckerman, B; Forveille, T; Kastner, J H

    1995-02-01

    Although stars form from clouds of gas and dust, there are insignificant amounts of gas around ordinary (Sun-like) stars. This suggests that hydrogen and helium, the primary constituents of planets such as Jupiter and Saturn, are not easily retained in orbit as a star matures. The gas-giant planets in the Solar System must therefore have formed rapidly. Models of their formation generally suggest that a solid core formed in < or = 10(6) yr, followed by the accretion of the massive gaseous envelope in approximately 10(7) yr (refs 1-5). But how and when the gas of the solar nebula dissipated, and how this compares with the predicted timescale of gas-giant formation, remains unclear, in part because direct observations of circumstellar gas have been made only for stars either younger or older than the critical range of 10(6)-10(7) yr (refs 8-15). Here we report observations of the molecular gas surrounding 20 stars whose ages are likely to be in this range. The gas dissipates rapidly; after a few million years the mass remaining is typically much less than the mass of Jupiter. Thus, if gas-giant planets are common in the Galaxy, they must form even more quickly than present models suggest.

  6. Polar vortex formation in giant-planet atmospheres due to moist convection

    NASA Astrophysics Data System (ADS)

    O'Neill, Morgan E.; Emanuel, Kerry A.; Flierl, Glenn R.

    2015-07-01

    A strong cyclonic vortex has been observed on each of Saturn’s poles, coincident with a local maximum in observed tropospheric temperature. Neptune also exhibits a relatively warm, although much more transient, region on its south pole. Whether similar features exist on Jupiter will be resolved by the 2016 Juno mission. Energetic, small-scale storm-like features that originate from the water-cloud level or lower have been observed on each of the giant planets and attributed to moist convection, suggesting that these storms play a significant role in global heat transfer from the hot interior to space. Nevertheless, the creation and maintenance of Saturn’s polar vortices, and their presence or absence on the other giant planets, are not understood. Here we use simulations with a shallow-water model to show that storm generation, driven by moist convection, can create a strong polar cyclone throughout the depth of a planet’s troposphere. We find that the type of shallow polar flow that occurs on a giant planet can be described by the size ratio of small eddies to the planetary radius and the energy density of its atmosphere due to latent heating from moist convection. We suggest that the observed difference in these parameters between Saturn and Jupiter may preclude a Jovian polar cyclone.

  7. Opportunities for Laboratory Opacity Chemistry Studies to Facilitate Characterization of Young Giant Planets and Brown Dwarfs

    NASA Technical Reports Server (NTRS)

    Marley, Mark; Freedman, Richard S.

    2015-01-01

    The thermal emission spectra of young giant planets is shaped by the opacity of atoms and molecules residing in their atmospheres. While great strides have been made in improving the opacities of important molecules, particularly NH3 and CH4, at high temperatures, much more work is needed to understand the opacity and chemistry of atomic Na and K. The highly pressure broadened fundamental band of Na and K in the optical stretches into the near-infrared, strongly influencing the shape of the Y and K spectral bands. Since young giant planets are bright in these bands it is important to understand the influences on the spectral shape. Discerning gravity and atmospheric composition is difficult, if not impossible, without both good atomic opacities as well as an excellent understanding of the relevant atmospheric chemistry. Since Na and K condense at temperatures near 500 to 600 K, the chemistry of the condensation process must be well understood as well, particularly any disequilibrium chemical pathways. Comparisons of the current generation of sophisticated atmospheric models and available data, however, reveal important shortcomings in the models. We will review the current state of observations and theory of young giant planets and will discuss these and other specific examples where improved laboratory measurements for alkali compounds have the potential of substantially improving our understanding of these atmospheres.

  8. COUPLED EVOLUTION WITH TIDES OF THE RADIUS AND ORBIT OF TRANSITING GIANT PLANETS: GENERAL RESULTS

    SciTech Connect

    Ibgui, Laurent; Burrows, Adam E-mail: burrows@astro.princeton.edu

    2009-08-01

    Some transiting extrasolar giant planets (EGPs) have measured radii larger than predicted by the standard theory. In this paper, we explore the possibility that an earlier episode of tidal heating can explain such radius anomalies and apply the formalism we develop to HD 209458b as an example. We find that for strong enough tides the planet's radius can undergo a transient phase of inflation that temporarily interrupts canonical, monotonic shrinking due to radiative losses. Importantly, an earlier episode of tidal heating can result in a planet with an inflated radius, even though its orbit has nearly circularized. Moreover, we confirm that at late times, and under some circumstances, by raising tides on the star itself a planet can spiral into its host. We note that a 3x to 10x solar planet atmospheric opacity with no tidal heating is sufficient to explain the observed radius of HD 209458b. However, our model demonstrates that with an earlier phase of episodic tidal heating, we can fit the observed radius of HD 209458b even with lower (solar) atmospheric opacities. This work demonstrates that, if a planet is left with an appreciable eccentricity after early inward migration and/or dynamical interaction, coupling radius and orbit evolution in a consistent fashion that includes tidal heating, stellar irradiation, and detailed model atmospheres might offer a generic solution to the inflated radius puzzle for transiting EGPs such as WASP-12b, TrES-4, and WASP-6b.

  9. Gas Giant Planets as Dynamical Barriers to Inward-Migrating Super-Earths

    NASA Astrophysics Data System (ADS)

    Morbidelli, Alessandro; Izidoro da Costa, Andre; Raymond, Sean

    2015-08-01

    Planets of 1-4 times Earth’s size on orbits shorter than 100 days exist around 30-50% of all Sun-like stars. In fact, the Solar System is particularly outstanding in its lack of “hot super-Earths” (or “mini-Neptunes”). These planets —or their building blocks—may have formed on wider orbits and migrated inward due to interactions with the gaseous protoplanetary disk. Here, we use a suite of dynamical simulations to show that gas giant planets act as barriers to the inward migration of super-Earths initially placed on more distant orbits. Jupiter’s early formation may have prevented Uranus and Neptune (and perhaps Saturn’s core) from becoming hot super-Earths. Our model predicts that the populations of hot super-Earth systems and Jupiter-like planets should be anti-correlated: gas giants (especially if they form early) should be rare in systems with many hot super-Earths. Testing this prediction will constitute a crucial assessment of the validity of the migration hypothesis for the origin of close-in super-Earths.

  10. The International Deep Planet Survey. II. The frequency of directly imaged giant exoplanets with stellar mass

    NASA Astrophysics Data System (ADS)

    Galicher, R.; Marois, C.; Macintosh, B.; Zuckerman, B.; Barman, T.; Konopacky, Q.; Song, I.; Patience, J.; Lafrenière, D.; Doyon, R.; Nielsen, E. L.

    2016-10-01

    Context. Radial velocity and transit methods are effective for the study of short orbital period exoplanets but they hardly probe objects at large separations for which direct imaging can be used. Aims: We carried out the international deep planet survey of 292 young nearby stars to search for giant exoplanets and determine their frequency. Methods: We developed a pipeline for a uniform processing of all the data that we have recorded with NIRC2/Keck II, NIRI/Gemini North, NICI/Gemini South, and NACO/VLT for 14 yr. The pipeline first applies cosmetic corrections and then reduces the speckle intensity to enhance the contrast in the images. Results: The main result of the international deep planet survey is the discovery of the HR 8799 exoplanets. We also detected 59 visual multiple systems including 16 new binary stars and 2 new triple stellar systems, as well as 2279 point-like sources. We used Monte Carlo simulations and the Bayesian theorem to determine that 1.05+2.80-0.70% of stars harbor at least one giant planet between 0.5 and 14 MJ and between 20 and 300 AU. This result is obtained assuming uniform distributions of planet masses and semi-major axes. If we consider power law distributions as measured for close-in planets instead, the derived frequency is 2.30+5.95-1.55%, recalling the strong impact of assumptions on Monte Carlo output distributions. We also find no evidence that the derived frequency depends on the mass of the hosting star, whereas it does for close-in planets. Conclusions: The international deep planet survey provides a database of confirmed background sources that may be useful for other exoplanet direct imaging surveys. It also puts new constraints on the number of stars with at least one giant planet reducing by a factor of two the frequencies derived by almost all previous works. Tables 11-15 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc

  11. Far Infrared and Submillimeter Observations of the Giant Planets

    NASA Technical Reports Server (NTRS)

    Loewenstein, R. F.; Harper, D. A.; Hildebrand, R. H.; Keene, J.; Orton, G. S.; Whitcomb, S. E.

    1984-01-01

    Far infrared measurements of the effective temperatures of Jupiter, Saturn, Uranus and Neptune were made. The measurements presented here cover the range from 35-1000 micrometers in relatively narrow bands. The observations at lambda 350 micrometers were made at the 3m NASA Infrared Telescope Facility (IRTF) of the Mauna Kea Observatory; those at lambda 350 micrometer were made on the Kuiper Airborne Observatory (KAO). All observations of Saturn were made when the ring inclination to Earth was 1.7 deg assuring an unambiguous measurement of the flux from the disk itself. Mars was used as the calibration reference. The results represent a consistent set of calibration standards. In these measurements, it is assumed that sub b(lambda = 350 micrometers) = T sub (lambda 350 micrometers). Measurements have been made of roughly 50% of the total flux emitted by Jupiter, 65% by Saturn, and 92% by Uranus and Neptune. These measurements therefore permit a considerable reduction in the uncertainties associated with the bolometric thermal outputs of the planets. The effective temperatures (T sub e) and the ratios of emitted to absorbed solar radiation were calculated.

  12. Atmosphere Models for the Brown Dwarf Gliese 229 B and the Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Marley, Mark S.

    1996-01-01

    Brown dwarfs inhabit a realm intermediate between the more massive stars and the less massive planets. Their thermal infrared emission is powered by the release of gravitational potential energy as regulated by their atmospheres. Long known only as theoretical constructs. the discovery of the first unimpeachable brown dwarf. Gliese 229 has opened up a new field: the study of brown dwarf atmospheres. The subsequent discoverv of numerous extrasolar giant planets circling nearby stars, further demonstrated the need for a comprehensive modeling effort to understand this new class of jovian atmospheres. Although no spectra are yet available of the new planets, the next generation of groundbased and spacebased telescopes will return such data. Here author report on the effort with Ames collaborator Dr. Christopher McKay to better understand these new atmospheres.

  13. Spectral researches of solar system giant planets using 2-m telescope at the Peak Terskol

    NASA Astrophysics Data System (ADS)

    Kuznyetsova, Yu.; Matsiaka, O.; Shliakhetskaya, Ya.; Krushevska, V.; Vidmachenko, A.; Andreev, M.; Sergeev, A.

    2014-03-01

    Results of observations, processing and an analysis of Uranus and Neptune spectra obtained from 2001-2012 are presented. Observations were carried out at the peak Terskol observatory (Northern Caucasus, Russia) using the coude échelle high-resolution spectrograph and the 2-meter mirror telescope Zeiss-2000. Data were obtained with spectral resolution R=45000 within 3700 - 9000 Ångstroms range. Combination of the specified equipment and spectral resolution allowed to solve the following problems: detecting of contribution of Raman scattering in planet spectra; calculating of spectral geometric albedo Ag taking into account of Raman scattering; research of long- and short-periodic variations for Ag and intensities of some chosen spectral lines; calculations of vertical structure parameters of giant planet atmospheres; search of ammonia NH3 lines in planet spectra. A comparative analysis of Uranus and Neptune spectra for different years was done.

  14. Search for Planets Companion to Late G-type Giant Stars

    NASA Astrophysics Data System (ADS)

    Liu, Yujuan; Zhao, Gang; Chen, Yuqin

    2005-03-01

    The searching for `other worlds' is one of the oldest well known scientific questions. With the first discovery of planets around the pulsar PSR1257+12 (Wolszczan & Frail 1992) and the main sequence star 51 Peg (Mayor & Queloz 1995), a new field of astronomy has been opened. Most of the planets have been found around main-sequence solar-mass stars. However in this investigation, we present our plan to search for planets around intermediate-mass late G type giant stars (1.5 - 3Msolar) with cooperation with Japanese astronomers and give the preliminary results of this research. A long-term monitoring of the Doppler velocities of stars will be carried out with mid-size telescopes at Okayama (Japan) and Xinglong (China).

  15. ASYMMETRIC FUNDAMENTAL BAND CO LINES AS A SIGN OF AN EMBEDDED GIANT PLANET

    SciTech Connect

    Regály, Zs.; Király, S.; Kiss, L. L.

    2014-04-20

    We investigate the formation of double-peaked asymmetric line profiles of CO in the fundamental band spectra emitted by young (1-5 Myr) protoplanetary disks hosted by a 0.5-2 M {sub ☉} star. Distortions of the line profiles can be caused by the gravitational perturbation of an embedded giant planet with q = 4.7 × 10{sup –3} stellar-to-planet mass ratio. Locally isothermal, two-dimensional hydrodynamic simulations show that the disk becomes globally eccentric inside the planetary orbit with stationary ∼0.2-0.25 average eccentricity after ∼2000 orbital periods. For orbital distances 1-10 AU, the disk eccentricity is peaked inside the region where the fundamental band of CO is thermally excited. Hence, these lines become sensitive indicators of the embedded planet via their asymmetries (both in flux and wavelength). We find that the line shape distortions (e.g., distance, central dip, asymmetry, and positions of peaks) of a given transition depend on the excitation energy (i.e., on the rotational quantum number J). The magnitude of line asymmetry is increasing/decreasing with J if the planet orbits inside/outside the CO excitation zone (R {sub CO} ≤ 3, 5, and 7 AU for a 0.5, 1, and 2 M {sub ☉} star, respectively), thus one can constrain the orbital distance of a giant planet by determining the slope of the peak asymmetry-J profile. We conclude that the presented spectroscopic phenomenon can be used to test the predictions of planet formation theories by pushing the age limits for detecting the youngest planetary systems.

  16. Giant Impacts on Terrestrial Planets: A High-Resolution 3D Study of Magma Ocean Formation and Atmospheric Blowoff

    NASA Astrophysics Data System (ADS)

    Stewart-Mukhopadhyay, Sarah

    The end stages of terrestrial planet formation are dominated by giant impact events, which may significantly affect the final composition of a planet. The physical changes from giant impacts include formation of magma oceans and atmospheric blowoff. We propose to conduct unique numerical experiments to investigate the physics of giant impacts in order to determine their effect on the thermal state and volatile budget of terrestrial planets (0.1 to 10 Earth masses). Proposed work: High-resolution 3D giant impacts between differentiated silicate-iron and ice-silicate planets will be modeled with both the widely-used CTH shock physics code and a new second-order Godunov finite-volume hydrocode called AREPO. AREPO's powerful arbitrary Lagrangian-Eulerian grid and computational efficiency allows for unprecedented resolution of planetary structure (e.g., crust and ocean). Expected results: (1) We will calculate the amount of melt generated and fraction of atmosphere lost during different classes of giant impacts (merging, graze and merge, hit and run, and erosion/disruption). (2) We will derive general scaling laws to describe these complicated phenomena. (3) We will consider the effect of re-accretion of ejected material at late times on the total thermal input of giant impact events. (4) And we will test the giant impact hypothesis for the high bulk density of Mercury by conducting orbital integrations of ejected debris to determine the amount of re-accreted mantle material for different impact orientations. The science team has an established collaborative body of work in giant impact simulations and hydrocode development. As in previous studies, the simulation results will be generalized into sets of simple equations describing collision outcomes that are suitable for N-body planet formation models. The proposed work supports the goals of the Origins of Solar Systems program by conducting a fundamental theoretical investigation of a key stage of planet formation

  17. SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets Around Young Stars

    NASA Technical Reports Server (NTRS)

    Tanner, Angelle; Beichman, Charles; Akeson, Rachel; Ghez, Andrea; Grankin, Konstantin N.; Herbst, William; Hillenbrand, Lynne; Huerta, Marcos; Konopacky, Quinn; Metchev, Stanimir; Mohanty, Subhanjoy; Prato, L.; Simon, Michal

    2008-01-01

    We present a review of precursor observing programs for the SIM PlanetQuest Key project devoted to detecting Jupiter mass planets around young stars. In order to ensure that the stars in the sample are free of various sources of astrometric noise that might impede the detection of planets, we have initiated programs to collect photometry, high contrast images, interferometric data and radial velocities for stars in both the Northern and Southern hemispheres. We have completed a high contrast imaging survey of target stars in Taurus and the Pleiades and found no definitive common proper motion companions within one arcsecond (140 AU) of the SIM targets. Our radial velocity surveys have shown that many of the target stars in Sco-Cen are fast rotators and a few stars in Taurus and the Pleiades may have sub-stellar companions. Interferometric data of a few stars in Taurus show no signs of stellar or sub-stellar companions with separations of <5 mas. The photometric survey suggests that approximately half of the stars initially selected for this program are variable to a degree (1(sigma) >0.1 mag) that would degrade the astrometric accuracy achievable for that star. While the precursor programs are still a work in progress, we provide a comprehensive list of all targets ranked according to their viability as a result of the observations taken to date. By far, the observable that removes the most targets from the SIM-YSO program is photometric variability.

  18. AN UNDERSTANDING OF THE SHOULDER OF GIANTS: JOVIAN PLANETS AROUND LATE K DWARF STARS AND THE TREND WITH STELLAR MASS

    SciTech Connect

    Gaidos, Eric; Fischer, Debra A.; Mann, Andrew W.; Howard, Andrew W.

    2013-07-01

    Analyses of exoplanet statistics suggest a trend of giant planet occurrence with host star mass, a clue to how planets like Jupiter form. One missing piece of the puzzle is the occurrence around late K dwarf stars (masses of 0.5-0.75 M{sub Sun} and effective temperatures of 3900-4800 K). We analyzed four years of Doppler radial velocity (RVs) data for 110 late K dwarfs, one of which hosts two previously reported giant planets. We estimate that 4.0% {+-} 2.3% of these stars have Saturn-mass or larger planets with orbital periods <245 days, depending on the planet mass distribution and RV variability of stars without giant planets. We also estimate that 0.7% {+-} 0.5% of similar stars observed by Kepler have giant planets. This Kepler rate is significantly (99% confidence) lower than that derived from our Doppler survey, but the difference vanishes if only the single Doppler system (HIP 57274) with completely resolved orbits is considered. The difference could also be explained by the exclusion of close binaries (without giant planets) from the Doppler but not Kepler surveys, the effect of long-period companions and stellar noise on the Doppler data, or an intrinsic difference between the two populations. Our estimates for late K dwarfs bridge those for solar-type stars and M dwarfs, and support a positive trend with stellar mass. Small sample size precludes statements about finer structure, e.g., a ''shoulder'' in the distribution of giant planets with stellar mass. Future surveys such as the Next Generation Transit Survey and the Transiting Exoplanet Satellite Survey will ameliorate this deficiency.

  19. THE EVOLUTION OF CIRCUMPLANETARY DISKS AROUND PLANETS IN WIDE ORBITS: IMPLICATIONS FOR FORMATION THEORY, OBSERVATIONS, AND MOON SYSTEMS

    SciTech Connect

    Shabram, Megan; Boley, Aaron C.

    2013-04-10

    Using radiation hydrodynamics simulations, we explore the evolution of circumplanetary disks around wide-orbit proto-gas giants. At large distances from the star ({approx}100 AU), gravitational instability followed by disk fragmentation can form low-mass substellar companions (massive gas giants and/or brown dwarfs) that are likely to host large disks. We examine the initial evolution of these subdisks and their role in regulating the growth of their substellar companions, as well as explore consequences of their interactions with circumstellar material. We find that subdisks that form in the context of GIs evolve quickly from a very massive state. Long-term accretion rates from the subdisk onto the proto-gas giant reach {approx}0.3 Jupiter masses kyr{sup -1}. We also find consistency with previous simulations, demonstrating that subdisks are truncated at {approx}1/3 of the companion's Hill radius and are thick, with (h/r) of {approx}> 0.2. The thickness of subdisks draws to question the use of thin-disk approximations for understanding the behavior of subdisks, and the morphology of subdisks has implications for the formation and extent of satellite systems. These subdisks create heating events in otherwise cold regions of the circumstellar disk and serve as planet formation beacons that can be detected by instruments such as ALMA.

  20. Zonal Flow Magnetic Field Interaction in the Semi-Conducting Region of Giant Planets

    NASA Astrophysics Data System (ADS)

    Cao, Hao; Stevenson, David J.

    2016-10-01

    All four giant planets in the Solar System feature zonal flows on the order of 100 m/s in the cloud deck, and large-scale intrinsic magnetic fields on the order of 1 Gauss near the surface. The vertical structure of the zonal flows remains obscure. The end-member scenarios are shallow flows confined in the radiative atmosphere and deep flows throughout the planet with constant velocity along the direction of the spin-axis. The electrical conductivity increases smoothly as a function of depth inside Jupiter and Saturn, while a discontinuity of electrical conductivity inside Uranus and Neptune cannot be ruled out. Deep zonal flows will inevitably interact with the magnetic field, at depth with even modest electrical conductivity. Here we investigate the interaction between zonal flows and magnetic fields in the semi-conducting region of giant planets. Employing mean-field electrodynamics, we show that the interaction will generate detectable poloidal magnetic field perturbations spatially correlated with the deep zonal flows. Assuming the peak amplitude of the dynamo α-effect to be 0.1 mm/s, deep zonal flows on the order of 0.1 – 1 m/s in the semi-conducting region of Jupiter and Saturn would generate poloidal magnetic perturbations on the order of 0.01 % – 1 % of the background dipole field. These poloidal perturbations should be detectable with the in-situ magnetic field measurements from the upcoming Juno mission and the Cassini Grand Finale. This implies that magnetic field measurements can be employed to constrain the properties of deep zonal flows in the semi-conducting region of giant planets.

  1. XUV-driven mass loss from extrasolar giant planets orbiting active stars

    NASA Astrophysics Data System (ADS)

    Chadney, J. M.; Galand, M.; Unruh, Y. C.; Koskinen, T. T.; Sanz-Forcada, J.

    2015-04-01

    Upper atmospheres of Hot Jupiters are subject to extreme radiation conditions that can result in rapid atmospheric escape. The composition and structure of the upper atmospheres of these planets are affected by the high-energy spectrum of the host star. This emission depends on stellar type and age, which are thus important factors in understanding the behaviour of exoplanetary atmospheres. In this study, we focus on Extrasolar Giant Planets (EPGs) orbiting K and M dwarf stars. XUV spectra for three different stars - ɛ Eridani, AD Leonis and AU Microscopii - are constructed using a coronal model. Neutral density and temperature profiles in the upper atmosphere of hypothetical EGPs orbiting these stars are then obtained from a fluid model, incorporating atmospheric chemistry and taking atmospheric escape into account. We find that a simple scaling based solely on the host star's X-ray emission gives large errors in mass loss rates from planetary atmospheres and so we have derived a new method to scale the EUV regions of the solar spectrum based upon stellar X-ray emission. This new method produces an outcome in terms of the planet's neutral upper atmosphere very similar to that obtained using a detailed coronal model of the host star. Our results indicate that in planets subjected to radiation from active stars, the transition from Jeans escape to a regime of hydrodynamic escape at the top of the atmosphere occurs at larger orbital distances than for planets around low activity stars (such as the Sun).

  2. Challenges in forming the solar system's giant planet cores via pebble accretion

    SciTech Connect

    Kretke, K. A.; Levison, H. F.

    2014-12-01

    Though ∼10 M {sub ⊕} mass rocky/icy cores are commonly held as a prerequisite for the formation of gas giants, theoretical models still struggle to explain how these embryos can form within the lifetimes of gaseous circumstellar disks. In recent years, aerodynamic-aided accretion of 'pebbles', objects ranging from centimeters to meters in size, has been suggested as a potential solution to this long-standing problem. While pebble accretion has been demonstrated to be extremely effective in local simulations that look at the detailed behavior of these pebbles in the vicinity of a single planetary embryo, to date there have been no global simulations demonstrating the effectiveness of pebble accretion in a more complicated, multi-planet environment. Therefore, we have incorporated the aerodynamic-aided accretion physics into LIPAD, a Lagrangian code that can follow the collisional/accretional/dynamical evolution of a protoplanetary system, to investigate how pebble accretion manifests itself in the larger planet formation picture. We find that under generic circumstances, pebble accretion naturally leads to an 'oligarchic' type of growth in which a large number of planetesimals grow to similar-sized planets. In particular, our simulations tend to form hundreds of Mars- and Earth-mass objects between 4 and 10 AU. While merging of some oligarchs may grow massive enough to form giant planet cores, leftover oligarchs lead to planetary systems that cannot be consistent with our own solar system. We investigate various ideas presented in the literature (including evaporation fronts and planet traps) and find that none easily overcome this tendency toward oligarchic growth.

  3. Extreme orbital evolution from hierarchical secular coupling of two giant planets

    SciTech Connect

    Teyssandier, Jean; Naoz, Smadar; Lizarraga, Ian; Rasio, Frederic A.

    2013-12-20

    Observations of exoplanets over the last two decades have revealed a new class of Jupiter-size planets with orbital periods of a few days, the so-called 'hot Jupiters'. Recent measurements using the Rossiter-McLaughlin effect have shown that many (∼50%) of these planets are misaligned; furthermore, some (∼15%) are even retrograde with respect to the stellar spin axis. Motivated by these observations, we explore the possibility of forming retrograde orbits in hierarchical triple configurations consisting of a star-planet inner pair with another giant planet, or brown dwarf, in a much wider orbit. Recently, it was shown that in such a system, the inner planet's orbit can flip back and forth from prograde to retrograde and can also reach extremely high eccentricities. Here we map a significant part of the parameter space of dynamical outcomes for these systems. We derive strong constraints on the orbital configurations for the outer perturber (the tertiary) that could lead to the formation of hot Jupiters with misaligned or retrograde orbits. We focus only on the secular evolution, neglecting other dynamical effects such as mean-motion resonances, as well as all dissipative forces. For example, with an inner Jupiter-like planet initially on a nearly circular orbit at 5 AU, we show that a misaligned hot Jupiter is likely to be formed in the presence of a more massive planetary companion (>2 M{sub J} ) within ∼140 AU of the inner system, with mutual inclination >50° and eccentricity above ∼0.25. This is in striking contrast to the test particle approximation, where an almost perpendicular configuration can still cause large-eccentricity excitations, but flips of an inner Jupiter-like planet are much less likely to occur. The constraints we derive can be used to guide future observations and, in particular, searches for more distant companions in systems containing a hot Jupiter.

  4. Gas Giant Planets as Dynamical Barriers to Inward-Migrating Super-Earths

    NASA Astrophysics Data System (ADS)

    Izidoro, André; Raymond, Sean N.; Morbidelli, Alessandro; Hersant, Franck; Pierens, Arnaud

    2015-02-01

    Planets of 1-4 times Earth’s size on orbits shorter than 100 days exist around 30-50% of all Sun-like stars. In fact, the Solar System is particularly outstanding in its lack of “hot super-Earths” (or “mini-Neptunes”). These planets—or their building blocks—may have formed on wider orbits and migrated inward due to interactions with the gaseous protoplanetary disk. Here, we use a suite of dynamical simulations to show that gas giant planets act as barriers to the inward migration of super-Earths initially placed on more distant orbits. Jupiter’s early formation may have prevented Uranus and Neptune (and perhaps Saturn’s core) from becoming hot super-Earths. Our model predicts that the populations of hot super-Earth systems and Jupiter-like planets should be anti-correlated: gas giants (especially if they form early) should be rare in systems with many hot super-Earths. Testing this prediction will constitute a crucial assessment of the validity of the migration hypothesis for the origin of close-in super-Earths.

  5. Formation and Survivability of Massive Giant Planets and Brown Dwarfs on Wide Orbitsfootnotemark

    NASA Astrophysics Data System (ADS)

    Vorobyov, E. I.; Basu, S.

    2012-07-01

    We present numerical hydrodynamics simulations showing the formation and survival of giant planets and brown dwarfs on extremely wide orbits (50-500 AU) around young solar-type stars via disk gravitational fragmentation. Fragments form at distances where gravitational fragmentation is allowed (50-300 AU), but most fragments do not survive and either migrate onto the forming star or get ejected into the intracluster medium via many-body interactions. The fragments that form near the end of the embedded phase, when torques from spiral arms become weaker and the probability of close encounters becomes smaller, may survive and mature into massive gas giants or brown dwarfs on wide orbits. The number of survived fragments is one to ten at best, in agreement with a small number of such detected objects. This phenomenon can explain the existence of massive exoplanets and brown dwarfs on wide orbits is such systems as Fomalhaut, HR 8799, and HIP 78530.

  6. Growing the gas-giant planets by the gradual accumulation of pebbles.

    PubMed

    Levison, Harold F; Kretke, Katherine A; Duncan, Martin J

    2015-08-20

    It is widely held that the first step in forming gas-giant planets, such as Jupiter and Saturn, was the production of solid 'cores' each with a mass roughly ten times that of the Earth. Getting the cores to form before the solar nebula dissipates (in about one to ten million years; ref. 3) has been a major challenge for planet formation models. Recently models have emerged in which 'pebbles' (centimetre-to-metre-sized objects) are first concentrated by aerodynamic drag and then gravitationally collapse to form objects 100 to 1,000 kilometres in size. These 'planetesimals' can then efficiently accrete left-over pebbles and directly form the cores of giant planets. This model is known as 'pebble accretion'; theoretically, it can produce cores of ten Earth masses in only a few thousand years. Unfortunately, full simulations of this process show that, rather than creating a few such cores, it produces a population of hundreds of Earth-mass objects that are inconsistent with the structure of the Solar System. Here we report that this difficulty can be overcome if pebbles form slowly enough to allow the planetesimals to gravitationally interact with one another. In this situation, the largest planetesimals have time to scatter their smaller siblings out of the disk of pebbles, thereby stifling their growth. Our models show that, for a large and physically reasonable region of parameter space, this typically leads to the formation of one to four gas giants between 5 and 15 astronomical units from the Sun, in agreement with the observed structure of the Solar System.

  7. Growing the gas-giant planets by the gradual accumulation of pebbles.

    PubMed

    Levison, Harold F; Kretke, Katherine A; Duncan, Martin J

    2015-08-20

    It is widely held that the first step in forming gas-giant planets, such as Jupiter and Saturn, was the production of solid 'cores' each with a mass roughly ten times that of the Earth. Getting the cores to form before the solar nebula dissipates (in about one to ten million years; ref. 3) has been a major challenge for planet formation models. Recently models have emerged in which 'pebbles' (centimetre-to-metre-sized objects) are first concentrated by aerodynamic drag and then gravitationally collapse to form objects 100 to 1,000 kilometres in size. These 'planetesimals' can then efficiently accrete left-over pebbles and directly form the cores of giant planets. This model is known as 'pebble accretion'; theoretically, it can produce cores of ten Earth masses in only a few thousand years. Unfortunately, full simulations of this process show that, rather than creating a few such cores, it produces a population of hundreds of Earth-mass objects that are inconsistent with the structure of the Solar System. Here we report that this difficulty can be overcome if pebbles form slowly enough to allow the planetesimals to gravitationally interact with one another. In this situation, the largest planetesimals have time to scatter their smaller siblings out of the disk of pebbles, thereby stifling their growth. Our models show that, for a large and physically reasonable region of parameter space, this typically leads to the formation of one to four gas giants between 5 and 15 astronomical units from the Sun, in agreement with the observed structure of the Solar System. PMID:26289203

  8. ATMOSPHERIC CHEMISTRY IN GIANT PLANETS, BROWN DWARFS, AND LOW-MASS DWARF STARS. III. IRON, MAGNESIUM, AND SILICON

    SciTech Connect

    Visscher, Channon; Lodders, Katharina; Fegley, Bruce E-mail: lodders@wustl.ed

    2010-06-20

    We use thermochemical equilibrium calculations to model iron, magnesium, and silicon chemistry in the atmospheres of giant planets, brown dwarfs, extrasolar giant planets (EGPs), and low-mass stars. The behavior of individual Fe-, Mg-, and Si-bearing gases and condensates is determined as a function of temperature, pressure, and metallicity. Our equilibrium results are thus independent of any particular model atmosphere. The condensation of Fe metal strongly affects iron chemistry by efficiently removing Fe-bearing species from the gas phase. Monatomic Fe is the most abundant Fe-bearing gas throughout the atmospheres of EGPs and L dwarfs, and in the deep atmospheres of giant planets and T dwarfs. Mg- and Si-bearing gases are effectively removed from the atmosphere by forsterite (Mg{sub 2}SiO{sub 4}) and enstatite (MgSiO{sub 3}) cloud formation. Monatomic Mg is the dominant magnesium gas throughout the atmospheres of EGPs and L dwarfs and in the deep atmospheres of giant planets and T dwarfs. Silicon monoxide (SiO) is the most abundant Si-bearing gas in the deep atmospheres of brown dwarfs and EGPs, whereas SiH{sub 4} is dominant in the deep atmosphere of Jupiter and other gas giant planets. Several other Fe-, Mg-, and Si-bearing gases become increasingly important with decreasing effective temperature. In principle, a number of Fe, Mg, and Si gases are potential tracers of weather or diagnostic of temperature in substellar atmospheres.

  9. Metal Hydride and Alkali Halide Opacities in Extrasolar Giant Planets and Cool Stellar Atmospheres

    NASA Technical Reports Server (NTRS)

    Weck, Philippe F.; Stancil, Phillip C.; Kirby, Kate; Schweitzer, Andreas; Hauschildt, Peter H.

    2006-01-01

    The lack of accurate and complete molecular line and continuum opacity data has been a serious limitation to developing atmospheric models of cool stars and Extrasolar Giant Planets (EGPs). We report our recent calculations of molecular opacities resulting from the presence of metal hydrides and alkali halides. The resulting data have been included in the PHOENIX stellar atmosphere code (Hauschildt & Baron 1999). The new models, calculated using spherical geometry for all gravities considered, also incorporate our latest database of nearly 670 million molecular lines, and updated equations of state.

  10. Molecular Line and Continuum Opacities for Modeling of Extrasolar Giant Planet and Cool Stellar Atmospheres

    NASA Technical Reports Server (NTRS)

    Weck, P. F.; Schweitzer, A.; Stancil, P. C.; Hauschildt, P. H.; Kirby, K.; Yamaguchi, Y.; Allen, W. D.

    2002-01-01

    The molecular line and continuum opacities are investigated in the atmospheres of cool stars and Extrasolar Giant Planets (EGPs). Using a combination of ab inito and experimentally derived potential curves and dipole transition moments, accurate data have been calculated for rovibrationally-resolved oscillator strengths and photodissociation cross sections in the B' (sup 2)Sigma+ (left arrow) X (sup 2)Sigma+ and A (sup 2)Pi (left arrow) X (sup 2)Sigma+ band systems in MgH. We also report our progress on the study of the electronic structure of LiCl and FeH.

  11. Molecular Line and Continuum Opacities for Modeling of Extrasolar Giant Planet and Cool Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Weck, P. F.; Stancil, P. C.; Schweitzer, A.; Hauschildt, P. H.; Kirby, K.; Yamaguchi, Y.; Allen, W.

    2002-11-01

    The molecular hue and continuum opacities are investigated in the atmospheres of cool stars and Extrasolar Giant Planets (EGPs). Using a combination of ab inito and experimentally derived potential curves and dipole transition moments, accurate data have been calculated for rovibrationally-resolved oscillator strengths and photodissociation cross sections in the B' 2∑+ ← X 2∑+ and A 2II ← X 2∑+ baud systems in MgH. We also report our progress on the study of the electronic structure of LiCl and FeH.

  12. Superionic and metallic states of water and ammonia at giant planet conditions.

    PubMed

    Cavazzoni, C; Chiarotti, G L; Scandolo, S; Tosatti, E; Bernasconi, M; Parrinello, M

    1999-01-01

    The phase diagrams of water and ammonia were determined by constant pressure ab initio molecular dynamic simulations at pressures (30 to 300 gigapascal) and temperatures (300 to 7000 kelvin) of relevance for the middle ice layers of the giant planets Neptune and Uranus. Along the planetary isentrope water and ammonia behave as fully dissociated ionic, electronically insulating fluid phases, which turn metallic at temperatures exceeding 7000 kelvin for water and 5500 kelvin for ammonia. At lower temperatures, the phase diagrams of water and ammonia exhibit a superionic solid phase between the solid and the ionic liquid. These simulations improve our understanding of the properties of the middle ice layers of Neptune and Uranus.

  13. Condensation of methane, ammonia, and water and the inhibition of convection in giant planets.

    PubMed

    Guillot, T

    1995-09-22

    The condensation of chemical species of high molecular mass such as methane, ammonia, and water can inhibit convection in the hydrogen-helium atmospheres of the giant planets. Convection is inhibited in Uranus and Neptune when methane reaches an abundance of about 15 times the solar value and in Jupiter and Saturn if the abundance of water is more than about five times the solar value. The temperature gradient consequently becomes superadiabatic, which is observed in temperature profiles inferred from radio-occultation measurements. The planetary heat flux is then likely to be transported by another mechanism, possibly radiation in Uranus, or diffusive convection.

  14. On Stellar Activity Enhancement Due to Interactions with Extrasolar Giant Planets.

    PubMed

    Cuntz; Saar; Musielak

    2000-04-20

    We present a first attempt to identify and quantify possible interactions between recently discovered extrasolar giant planets (and brown dwarfs) and their host stars, resulting in activity enhancement in the stellar outer atmospheres. Many extrasolar planets have masses comparable to or larger than Jupiter and are within a distance of 0.5 AU, suggesting the possibility of their significant influence on stellar winds, coronae, and even chromospheres. Beyond the well-known rotational synchronization, the interactions include tidal effects (in which enhanced flows and turbulence in the tidal bulge lead to increased magnetoacoustic heating and dynamo action) and direct magnetic interaction between the stellar and planetary magnetic fields. We discuss relevant parameters for selected systems and give preliminary estimates of the relative interaction strengths.

  15. Investigating the Orbital Period Valley of Giant Planets in Kepler Data

    NASA Astrophysics Data System (ADS)

    Thomas, Brianna P.; Birkby, Jayne L.

    2016-01-01

    Transit light curves contain a wealth of information about the basic properties of a planet, such as its radius, semi-major axis, and orbital period. For the latter property, there is a distinct lack of planets with periods between 10 to 100 days. This gap could be caused by something as simple as observational bias, or as prominent as planetary formation or migration. Here, we report an investigation into the atmosphere of planets within this orbital period valley, to search for differences that may indicate a different formation mechanism or migration path to those outside of it. We do this by searching for the secondary eclipse of planets in the valley in order to measure their albedos. We determined an optimal target for this: KOI-366 b (P ~ 75 days). However, we find that despite the exquisite precision of Kepler data, it cannot constrain the albedo for this long-orbit planet candidate. We measure a 1σ upper limit on the geometric albedo of Ag,1σ ≤ 2.0. We highlight that additional scatter in the light curve is likely caused by a ~ 2-day pulsation of the giant host star, and that further data is required to measure the secondary eclipse. KOI-366 is one of the best suited of all host stars with long period exoplanet candidates for follow-up due to its relatively bright magnitude (Kp = 11.7 mag), but the full investigation of the reflective properties of long period planets may require space-based observations from future instruments, such as WFIRST, that will be more sensitive to objects further away from their host stars. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.

  16. Correlations between Compositions and Orbits Established by the Giant Impact Era of Planet Formation

    NASA Astrophysics Data System (ADS)

    Dawson, Rebekah I.; Lee, Eve J.; Chiang, Eugene

    2016-05-01

    The giant impact phase of terrestrial planet formation establishes connections between super-Earths’ orbital properties (semimajor axis spacings, eccentricities, mutual inclinations) and interior compositions (the presence or absence of gaseous envelopes). Using N-body simulations and analytic arguments, we show that spacings derive not only from eccentricities, but also from inclinations. Flatter systems attain tighter spacings, a consequence of an eccentricity equilibrium between gravitational scatterings, which increase eccentricities, and mergers, which damp them. Dynamical friction by residual disk gas plays a critical role in regulating mergers and in damping inclinations and eccentricities. Systems with moderate gas damping and high solid surface density spawn gas-enveloped super-Earths with tight spacings, small eccentricities, and small inclinations. Systems in which super-Earths coagulate without as much ambient gas, in disks with low solid surface density, produce rocky planets with wider spacings, larger eccentricities, and larger mutual inclinations. A combination of both populations can reproduce the observed distributions of spacings, period ratios, transiting planet multiplicities, and transit duration ratios exhibited by Kepler super-Earths. The two populations, both formed in situ, also help to explain observed trends of eccentricity versus planet size, and bulk density versus method of mass measurement (radial velocities versus transit timing variations). Simplifications made in this study—including the limited time span of the simulations, and the approximate treatments of gas dynamical friction and gas depletion history—should be improved on in future work to enable a detailed quantitative comparison to the observations.

  17. Decoupling of a giant planet from its disk in an inclined binary system

    NASA Astrophysics Data System (ADS)

    Marzari, F.; Picogna, G.

    According to \\cite{Triaud_2010} and \\cite{Albrecht_2012} about 40% of hot Jupiters have orbits significantly tilted respect to the equatorial plane of the star. It has been suggested \\cite{Batygin_2012} that the evolution of a protoplanetary disk under the perturbations of a binary companion may be responsible for the observed spin-orbit misalignment of these exoplanets. A fundamental requirement for this model to work is that the planet is kept within the disk during its precession. In this way the planet would continue its migration by tidal interaction with the disk and, at the same time, once the disk is dissipated it would maintain its inclination. Previous studies seem to suggest that indeed a giant planet is forced to evolve within the disks even in presence of strong perturbing forces as those induced by a companion star. By using two different SPH codes (VINE and phantom) we show that on the long term the planet definitively decouples from the disk evolution and its orbital plane significantly departs from that of the disk. For a detailed analysis an discussion we refer to \\cite{Picogna_2015}.

  18. Detecting Close-In Extrasolar Giant Planets with the Kepler Photometer via Scattered Light

    NASA Astrophysics Data System (ADS)

    Jenkins, J. M.; Doyle, L. R.; Kepler Discovery Mission Team

    2003-05-01

    NASA's Kepler Mission will be launched in 2007 primarily to search for transiting Earth-sized planets in the habitable zones of solar-like stars. In addition, it will be poised to detect the reflected light component from close-in extrasolar giant planets (CEGPs) similar to 51 Peg b. Here we use the DIARAD/SOHO time series along with models for the reflected light signatures of CEGPs to evaluate Kepler's ability to detect such planets. We examine the detectability as a function of stellar brightness, stellar rotation period, planetary orbital inclination angle, and planetary orbital period, and then estimate the total number of CEGPs that Kepler will detect over its four year mission. The analysis shows that intrinsic stellar variability of solar-like stars is a major obstacle to detecting the reflected light from CEGPs. Monte Carlo trials are used to estimate the detection threshold required to limit the total number of expected false alarms to no more than one for a survey of 100,000 stellar light curves. Kepler will likely detect 100-760 51 Peg b-like planets by reflected light with orbital periods up to 7 days. LRD was supported by the Carl Sagan Chair at the Center for the Study of Life in the Universe, a division of the SETI Institute. JMJ received support from the Kepler Mission Photometer and Science Office at NASA Ames Research Center.

  19. Persistent circumpolar vortices on the extrasolar giant planet HD 37605 b

    NASA Astrophysics Data System (ADS)

    Langton, J.; Laughlin, G.

    2008-06-01

    Aims: We examine the atmospheric dynamics on the extrasolar gas giant HD 37605 b (P=54.2 d). As this planet's orbit is highly eccentric (e=0.737), the intensity of stellar heating varies by a factor of 40 over the course of an orbit. We also consider the effect of cloud formation on the dynamical flows and the temperature evolution resulting from this extremely variable forcing. Methods: We employ a grid-based two-dimensional compressible hydrodynamics code to model the atmosphere of the extrasolar giant planet HD 37605 b. We use a resolution of 512 longitude gridpoints and 257 latitude gridpoints. The stellar heating is simulated using a one-layer, two-frequency, two-stream approximation to true radiative transfer. Results: This time-dependent insolation causes the formation of circumpolar vortices near both poles. These vortices appear to be stable over many orbits, and sequester a large volume of cold air, effectively shielding their interiors from the full blast of irradiation at periastron. Evolution of tracers initially placed within these vortices shows the rate of exchange of material between the interior and exterior of these vortices is small: material initially inside the vortex can be expected to remain in the vortex for ~2 P. We note that this result is contingent upon a cloudless atmosphere; the formation of clouds potentially causes a large reduction in both temperature variation and wind speed.

  20. Ammonium hydrosulfide and clouds in the atmospheres of the giant planets.

    NASA Astrophysics Data System (ADS)

    Ibragimov, K. Yu.; Solodovnik, A. A.

    The physicochemical properties of two possible compounds - ammonium hydrosulfide (NH4SH) and ammonium sulfide (NH4)2S - that may be formed in a reaction of ammonia NH3 with hydrogen sulfide H2S are discussed, and the probability of their formation is analyzed on the basis of the Le Chatelier principle. It is shown that the conditions of their formation on the basis of available data on the concentration ratio of the reagents (NH3 and H2S) in the atmospheres of giant planets make the appearance of enough NH4SH for cloud formation highly problematic. Accordingly, the authors propose as an alternative candidate for a cloud-forming role ammonium sulfide (NH4)2S, for whose formation the conditions in the atmospheres of the giant planets are more favorable. The possible spatial localization of (NH4)2S clouds is estimated, and the result is used in an attempt to identify this compound as one of the chromophores.

  1. Building the giant planet cores by convergent migration of pebble-accreting embryos

    NASA Astrophysics Data System (ADS)

    Chrenko, Ondrej; Broz, Miroslav

    2016-10-01

    An explanation of the accretion buildup of giant planet cores on rather short (~Myr) time scales remains a long-standing challenge for scenarios of planetary system formation. One of the recently proposed processes that can take part during this evolutionary stage is the convergent Type I migration of Earth-sized embryos towards the zero-torque radius, occurring at an opacity transition within the dusty-gaseous protoplanetary disk (e.g. Pierens et al. 2013). Inconveniently, simulations show that such groups of embryos do not merge easily because they often get locked in mutual mean-motion resonances and consequently form an inward-migrating convoy.We revise this possibility of merging embryos while taking into account their ongoing growth by pebble accretion. Our aim is to check whether the rapid changes of masses combined with the migration of embryos through the feeding zone can break the resonant chain and allow for the giant planet core formation.The environment of the protoplanetary disk is modeled with the 2D FARGO code (Masset 2000), which we modified in order to perform non-isothermal hydrodynamic simulations, assuming flux-limited radiative diffusion (Levermore & Pomraning 1981). The embedded massive bodies are evolved simultaneously in 3D using the hybrid Wisdom-Holman/Gauss-Radau integrator from the Rebound package (Rein & Spiegel 2015). A semi-analytic method is used to evolve the masses of embryos by pebble accretion (e.g. Levison et al. 2015).

  2. Short-term collisional evolution of a disc perturbed by a giant-planet embryo

    NASA Astrophysics Data System (ADS)

    Charnoz, S.; Thébault, P.; Brahic, A.

    2001-07-01

    A simple numerical model has been developed to study the evolution of a disc of planetesimals under mutual inelastic collisions in the potential field of a central body and of an embedded giant-planet embryo. Masses for the latter range from 0.5 to 300 Earth masses. A mass of 15 Moplus is typical of the solid-core model for the formation of giant planets. The initially cold disc consists of a few thousand particles. Those initially present between one and three Hill radii from the perturber's orbit are transferred to very eccentric orbits causing violent collisions throughout the disc. The perturbation propagates far from the perturber, like a heat transfer: a 15 Moplus perturber orbiting at 5.2 a.u. heats up the disc from 2.3 to at least 11 a.u. from the central body in a few 105 to 106 years. Relative velocities are typically increased by a factor of 10 to 100. The extent of the heated region increases with the protoplanet's mass while the propagation timescale decreases. The resulting radial mixing has potential applications for the origin of the Asteroid Belt, in particular for the radial distribution of the asteroid's spectroscopic families.

  3. Habitability of super-Earth planets around other suns: models including Red Giant Branch evolution.

    PubMed

    von Bloh, W; Cuntz, M; Schröder, K-P; Bounama, C; Franck, S

    2009-01-01

    The unexpected diversity of exoplanets includes a growing number of super-Earth planets, i.e., exoplanets with masses of up to several Earth masses and a similar chemical and mineralogical composition as Earth. We present a thermal evolution model for a 10 Earth-mass planet orbiting a star like the Sun. Our model is based on the integrated system approach, which describes the photosynthetic biomass production and takes into account a variety of climatological, biogeochemical, and geodynamical processes. This allows us to identify a so-called photosynthesis-sustaining habitable zone (pHZ), as determined by the limits of biological productivity on the planetary surface. Our model considers solar evolution during the main-sequence stage and along the Red Giant Branch as described by the most recent solar model. We obtain a large set of solutions consistent with the principal possibility of life. The highest likelihood of habitability is found for "water worlds." Only mass-rich water worlds are able to realize pHZ-type habitability beyond the stellar main sequence on the Red Giant Branch.

  4. Habitability of super-Earth planets around other suns: models including Red Giant Branch evolution.

    PubMed

    von Bloh, W; Cuntz, M; Schröder, K-P; Bounama, C; Franck, S

    2009-01-01

    The unexpected diversity of exoplanets includes a growing number of super-Earth planets, i.e., exoplanets with masses of up to several Earth masses and a similar chemical and mineralogical composition as Earth. We present a thermal evolution model for a 10 Earth-mass planet orbiting a star like the Sun. Our model is based on the integrated system approach, which describes the photosynthetic biomass production and takes into account a variety of climatological, biogeochemical, and geodynamical processes. This allows us to identify a so-called photosynthesis-sustaining habitable zone (pHZ), as determined by the limits of biological productivity on the planetary surface. Our model considers solar evolution during the main-sequence stage and along the Red Giant Branch as described by the most recent solar model. We obtain a large set of solutions consistent with the principal possibility of life. The highest likelihood of habitability is found for "water worlds." Only mass-rich water worlds are able to realize pHZ-type habitability beyond the stellar main sequence on the Red Giant Branch. PMID:19630504

  5. First-Principles Computer Simulations of Dense Plasmas and Application to the Interiors of Giant Planets

    NASA Astrophysics Data System (ADS)

    Militzer, Burkhard

    2013-06-01

    This presentation will review three recent applications of first-principles computer simulation techniques to study matter at extreme temperature-pressure conditions that are of relevance to astrophysics. First we report a recent methodological advance in all-electron path integral Monte Carlo (PIMC) that allowed us to extend this method beyond hydrogen and helium to elements with core electrons [1]. We combine results from PIMC and with density functional molecular dynamics (DFT-MD) simulations and derive a coherent equation of state (EOS) for water and carbon plasmas in the regime from 1-50 Mbar and 104-109 K that can be compared to laboratory shock wave experiments. Second we apply DFT-MD simulations to characterize superionic water in the interiors of Uranus and Neptune. By adopting a thermodynamic integration technique, we derive the Gibbs free energy in order to demonstrate the existence of a phase transformation from body-centered cubic to face-centered cubic superionic water [2]. Finally we again use DFT-MD to study the interiors of gas giant planets. We determine the EOS for hydrogen-helium mixtures spanning density-temperature conditions in the deep interiors of giant planets, 0.2-9.0 g/cc and 1000-80000 K [3]. We compare the simulation results with the semi-analytical EOS model by Saumon and Chabrier. We present a revision to the mass-radius relationship which makes the hottest exoplanets increase in radius by ~0.2 Jupiter radii at fixed entropy and for masses greater than 0.5 Jupiter masses. This change is large enough to have possible implications for some discrepant inflated giant exoplanets. We conclude by demonstrating that all materials in the cores of giant planets, ices, MgO, SiO2, and iron, will all dissolve into metallic hydrogen. This implies the cores of Jupiter and Saturn have been at least partially eroded. [1] K. P. Driver, B. Militzer, Phys. Rev. Lett. 108 (2012) 115502. [2] H. F. Wilson, M. L. Wong, B. Militzer, http://arxiv.org/abs/1211

  6. Disk evolution, element abundances and cloud properties of young gas giant planets.

    PubMed

    Helling, Christiane; Woitke, Peter; Rimmer, Paul B; Kamp, Inga; Thi, Wing-Fai; Meijerink, Rowin

    2014-04-14

    We discuss the chemical pre-conditions for planet formation, in terms of gas and ice abundances in a protoplanetary disk, as function of time and position, and the resulting chemical composition and cloud properties in the atmosphere when young gas giant planets form, in particular discussing the effects of unusual, non-solar carbon and oxygen abundances. Large deviations between the abundances of the host star and its gas giants seem likely to occur if the planet formation follows the core-accretion scenario. These deviations stem from the separate evolution of gas and dust in the disk, where the dust forms the planet cores, followed by the final run-away accretion of the left-over gas. This gas will contain only traces of elements like C, N and O, because those elements have frozen out as ices. PRODIMO protoplanetary disk models are used to predict the chemical evolution of gas and ice in the midplane. We find that cosmic rays play a crucial role in slowly un-blocking the CO, where the liberated oxygen forms water, which then freezes out quickly. Therefore, the C/O ratio in the gas phase is found to gradually increase with time, in a region bracketed by the water and CO ice-lines. In this regions, C/O is found to approach unity after about 5 Myrs, scaling with the cosmic ray ionization rate assumed. We then explore how the atmospheric chemistry and cloud properties in young gas giants are affected when the non-solar C/O ratios predicted by the disk models are assumed. The DRIFT cloud formation model is applied to study the formation of atmospheric clouds under the influence of varying premordial element abundances and its feedback onto the local gas. We demonstrate that element depletion by cloud formation plays a crucial role in converting an oxygen-rich atmosphere gas into carbon-rich gas when non-solar, premordial element abundances are considered as suggested by disk models.

  7. Disk Evolution, Element Abundances and Cloud Properties of Young Gas Giant Planets

    PubMed Central

    Helling, Christiane; Woitke, Peter; Rimmer, Paul B.; Kamp, Inga; Thi, Wing-Fai; Meijerink, Rowin

    2014-01-01

    We discuss the chemical pre-conditions for planet formation, in terms of gas and ice abundances in a protoplanetary disk, as function of time and position, and the resulting chemical composition and cloud properties in the atmosphere when young gas giant planets form, in particular discussing the effects of unusual, non-solar carbon and oxygen abundances. Large deviations between the abundances of the host star and its gas giants seem likely to occur if the planet formation follows the core-accretion scenario. These deviations stem from the separate evolution of gas and dust in the disk, where the dust forms the planet cores, followed by the final run-away accretion of the left-over gas. This gas will contain only traces of elements like C, N and O, because those elements have frozen out as ices. ProDiMo protoplanetary disk models are used to predict the chemical evolution of gas and ice in the midplane. We find that cosmic rays play a crucial role in slowly un-blocking the CO, where the liberated oxygen forms water, which then freezes out quickly. Therefore, the C/O ratio in the gas phase is found to gradually increase with time, in a region bracketed by the water and CO ice-lines. In this regions, C/O is found to approach unity after about 5 Myrs, scaling with the cosmic ray ionization rate assumed. We then explore how the atmospheric chemistry and cloud properties in young gas giants are affected when the non-solar C/O ratios predicted by the disk models are assumed. The Drift cloud formation model is applied to study the formation of atmospheric clouds under the influence of varying premordial element abundances and its feedback onto the local gas. We demonstrate that element depletion by cloud formation plays a crucial role in converting an oxygen-rich atmosphere gas into carbon-rich gas when non-solar, premordial element abundances are considered as suggested by disk models. PMID:25370190

  8. The ODINUS Mission Concept: a Mission to the Ice Giant Planets

    NASA Astrophysics Data System (ADS)

    Turrini, Diego; Politi, Romolo; Peron, Roberto; Grassi, Davide; Plainaki, Christina; Barbieri, Mauro; Massimo Lucchesi, David; Magni, Gianfranco; Altieri, Francesca; Cottini, Valeria; Gorius, Nicolas; Gaulme, Patrick; Schmider, François-Xavier; Adriani, Alberto; Piccioni, Giuseppe

    2014-05-01

    We present the scientific case and the mission concept for the comparative exploration of the ice giant planets Uranus and Neptune and their satellites with a pair of twin spacecraft: ODINUS (Origins, Dynamics and Interiors of Neptunian and Uranian Systems). The ODINUS proposal was submitted in response to the call for white papers for the definition of the themes of the L2 and L3 mission in the framework of the ESA Cosmic Vision 2015-2025 program. The goal of ODINUS is the advancement of our understanding of the ancient past of the Solar System and, more generally, of how planetary systems form and evolve. The mission concept is focused on providing elements to answer to the scientific themes of the Cosmic Vision 2015-2025 program: What are the conditions for planetary formation and the emergency of life? How does the Solar System work? What are the fundamental physical laws of the Universe? In order to achieve its goals, the ODINUS mission concept proposed the use of two twin spacecraft to be put in orbit around Uranus and Neptune respectively, with selected flybys of their satellites. The proposed measurements aim to study the atmospheres and magnetospheres of the planets, the surfaces of the satellites, and the interior structure and composition of both satellites and planets. An important possibility for performing fundamental physics studies (among them tests of general relativity theory) is offered by the cruise phase. After the extremely positive evaluation of ESA Senior Survey Committee, who stated that 'the exploration of the icy giants appears to be a timely milestone, fully appropriate for an L class mission', we discuss strategies to comparatively study Uranus and Neptune with future international missions.

  9. The ODINUS Mission Concept: a Mission for the exploration the Ice Giant Planets

    NASA Astrophysics Data System (ADS)

    Peron, Roberto

    We present the scientific case and the mission concept of a proposal for the the comparative exploration of the ice giant planets Uranus and Neptune and their satellites with a pair of twin spacecraft: ODINUS (Origins, Dynamics and Interiors of Neptunian and Uranian Systems). The ODINUS proposal was submitted in response to the call for white papers for the definition of the themes of the L2 and L3 mission in the framework of ESA Cosmic Vision 2015-2025 program. The goal of ODINUS is the advancement of our understanding of the ancient past of the Solar System and, more generally, of how planetary systems form and evolve. The mission concept is focused on providing elements to answer to the scientific themes of the Cosmic Vision 2015-2025 program: What are the conditions for planetary formation and the emergency of life? How does the Solar System work? What are the fundamental physical laws of the Universe? In order to achieve its goals, ODINUS foresees the use of two twin spacecraft to be placed in orbit around Uranus and Neptune respectively, with selected flybys of their satellites. The proposed measurements aim to study the atmospheres and magnetospheres of the planets, the surfaces of the satellites, and the interior structure and composition of both satellites and planets. An important possibility for performing fundamental physics studies (among them tests of general relativity theory) is offered by the cruise phase. After the extremely positive evaluation of ESA Senior Survey Committee, who stated that ``the exploration of the icy giants appears to be a timely milestone, fully appropriate for an L class mission'', we discuss strategies to comparatively study Uranus and Neptune with future international missions.

  10. ELEMENTAL ABUNDANCE DIFFERENCES IN THE 16 CYGNI BINARY SYSTEM: A SIGNATURE OF GAS GIANT PLANET FORMATION?

    SciTech Connect

    RamIrez, I.; Roederer, I. U.; Fish, J. R.; Melendez, J.

    2011-10-20

    The atmospheric parameters of the components of the 16 Cygni binary system, in which the secondary has a gas giant planet detected, are measured accurately using high-quality observational data. Abundances relative to solar are obtained for 25 elements with a mean error of {sigma}([X/H]) = 0.023 dex. The fact that 16 Cyg A has about four times more lithium than 16 Cyg B is normal considering the slightly different masses of the stars. The abundance patterns of 16 Cyg A and B, relative to iron, are typical of that observed in most of the so-called solar twin stars, with the exception of the heavy elements (Z > 30), which can, however, be explained by Galactic chemical evolution. Differential (A-B) abundances are measured with even higher precision ({sigma}({Delta}[X/H]) = 0.018 dex, on average). We find that 16 Cyg A is more metal-rich than 16 Cyg B by {Delta}[M/H] = +0.041 {+-} 0.007 dex. On an element-to-element basis, no correlation between the A-B abundance differences and dust condensation temperature (T{sub C}) is detected. Based on these results, we conclude that if the process of planet formation around 16 Cyg B is responsible for the observed abundance pattern, the formation of gas giants produces a constant downward shift in the photospheric abundance of metals, without a T{sub C} correlation. The latter would be produced by the formation of terrestrial planets instead, as suggested by other recent works on precise elemental abundances. Nevertheless, a scenario consistent with these observations requires the convective envelopes of {approx_equal} 1 M{sub sun} stars to reach their present-day sizes about three times quicker than predicted by standard stellar evolution models.

  11. Connecting Young Brown Dwarfs and Directly Imaged Gas-Giant Planets

    NASA Astrophysics Data System (ADS)

    Liu, Michael; Dupuy, Trent; Allers, Katelyn; Aller, Kimberly; Best, William; Magnier, Eugene

    2015-12-01

    Direct detections of gas-giant exoplanets and discoveries of young (~10-100 Myr) field brown dwarfs from all-sky surveys are strengthening the link between the exoplanet and brown dwarf populations, given the overlapping ages, masses, temperatures, and surface gravities. In light of the relatively small number of directly imaged planets and the modest associated datasets, the large census of young field brown dwarfsprovides a compelling laboratory for enriching our understanding of both classes of objects. However, work to date on young field objects has typically focused on individual discoveries.We present a large comprehensive study of the youngest field brown dwarfs, comprising both previously known objects and our new discoveries from the latest wide-field surveys (Pan-STARRS-1 and WISE). With masses now extending down to ~5 Jupiter masses, these objects have physical properties that largely overlap young gas-giant planets and thus are promising analogs for studying exoplanet atmospheres at unparalleled S/N, spectral resolution, and wavelength coverage. We combine high-quality spectra and parallaxes to determine spectral energy distributions, luminosities, temperatures, and ages for young field objects. We demonstrate that this population spans a continuum in the color-magnitude diagram, thereby forming a bridge between the hot and cool extremes of directly imaged planets. We find that the extremely dusty properties of the planets around 2MASS J1207-39 and HR 8799 do occur in some young brown dwarfs, but these properties do not have a simple correspondence with age, perhaps contrary to expectations. We find young field brown dwarfs can have unusually low temperatures and suggest a new spectral type-temperature scale appropriate for directly imaged planets.To help provide a reference for extreme-contrast imaging surveys, we establish a grid of spectral standards and benchmarks, based on membership in nearby young moving groups, in order to calibrate gravity

  12. ON THE SURVIVAL OF BROWN DWARFS AND PLANETS ENGULFED BY THEIR GIANT HOST STAR

    SciTech Connect

    Passy, Jean-Claude; Mac Low, Mordecai-Mark; De Marco, Orsola

    2012-11-10

    The recent discovery of two Earth-mass planets in close orbits around an evolved star has raised questions as to whether substellar companions can survive encounters with their host stars. We consider whether these companions could have been stripped of significant amounts of mass during the phase when they orbited through the dense inner envelopes of the giant. We apply the criterion derived by Murray et al. for disruption of gravitationally bound objects by ram pressure to determine whether mass loss may have played a role in the histories of these and other recently discovered low-mass companions to evolved stars. We find that the brown dwarf and Jovian-mass objects circling WD 0137-349, SDSS J08205+0008, and HIP 13044 are most unlikely to have lost significant mass during the common envelope phase. However, the Earth-mass planets found around KIC 05807616 could well be the remnants of one or two Jovian-mass planets that lost extensive mass during the common envelope phase.

  13. ON THE EFFECT OF GIANT PLANETS ON THE SCATTERING OF PARENT BODIES OF IRON METEORITE FROM THE TERRESTRIAL PLANET REGION INTO THE ASTEROID BELT: A CONCEPT STUDY

    SciTech Connect

    Haghighipour, Nader; Scott, Edward R. D.

    2012-04-20

    In their model for the origin of the parent bodies of iron meteorites, Bottke et al. proposed differentiated planetesimals, formed in 1-2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these objects and their fragments were scattered into the asteroid belt as a result of interactions with planetary embryos. Although viable, this model does not include the effect of a giant planet that might have existed or been growing in the outer regions. We present the results of a concept study where we have examined the effect of a planetary body in the orbit of Jupiter on the early scattering of planetesimals from the terrestrial region into the asteroid belt. We integrated the orbits of a large battery of planetesimals in a disk of planetary embryos and studied their evolutions for different values of the mass of the planet. Results indicate that when the mass of the planet is smaller than 10 M{sub Circled-Plus }, its effects on the interactions among planetesimals and planetary embryos are negligible. However, when the planet mass is between 10 and 50 M{sub Circled-Plus }, simulations point to a transitional regime with {approx}50 M{sub Circled-Plus} being the value for which the perturbing effect of the planet can no longer be ignored. Simulations also show that further increase of the mass of the planet strongly reduces the efficiency of the scattering of planetesimals from the terrestrial planet region into the asteroid belt. We present the results of our simulations and discuss their possible implications for the time of giant planet formation.

  14. INTERACTIONS BETWEEN MODERATE- AND LONG-PERIOD GIANT PLANETS: SCATTERING EXPERIMENTS FOR SYSTEMS IN ISOLATION AND WITH STELLAR FLYBYS

    SciTech Connect

    Boley, Aaron C.; Payne, Matthew J.; Ford, Eric B.

    2012-07-20

    The chance that a planetary system will interact with another member of its host star's nascent cluster would be greatly increased if gas giant planets form in situ on wide orbits. In this paper, we explore the outcomes of planet-planet scattering for a distribution of multi-planet systems that all have one of the planets on an initial orbit of 100 AU. The scattering experiments are run with and without stellar flybys. We convolve the outcomes with distributions for protoplanetary disk and stellar cluster sizes to generalize the results where possible. We find that the frequencies of large mutual inclinations and high eccentricities are sensitive to the number of planets in a system, but not strongly to stellar flybys. However, flybys do play a role in changing the low and moderate portions of the mutual inclination distributions, and erase dynamically cold initial conditions on average. Wide-orbit planets can be mixed throughout the planetary system, and in some cases, can potentially become hot Jupiters, which we demonstrate using scattering experiments that include a tidal damping model. If planets form in situ on wide orbits, then there will be discernible differences in the proper-motion distributions of a sample of wide-orbit planets compared with a pure scattering formation mechanism. Stellar flybys can enhance the frequency of ejections in planetary systems, but autoionization is likely to remain the dominant source of free-floating planets.

  15. News and Views: Low-mass stars pull weight in globular clusters; Red dwarf planets are common, too; More planets than stars in the Milky Way? After Bullet comes Musket Ball; Planets survive red giant phase

    NASA Astrophysics Data System (ADS)

    2012-02-01

    Gravitational microlensing techniques have uncovered the first low-mass star found in a globular cluster, suggesting that previously undetectable stars may contribute to cluster masses, meaning that there is less dark matter to find. Data from NASA's Kepler mission suggest that small rocky planets may be common orbiting red dwarf stars - and because red dwarfs are common types of star, this means that rocky planets may be commonplace in the Milky Way. A survey using gravitational microlensing suggest that exoplanets are the exception rather than the rule in the Milky Way - and that small planets like Earth are more common than gas and ice giants. The Bullet Cluster famously allows mapping of the dark matter distribution during the merger of two clusters. Now a merging cluster named the Musket Ball shows a later stage in the process. Planets are not necessarily vaporized when a red giant star expands; the cores of gas giants may survive, but they would not be pleasant places to live. Data from NASA's Kepler mission has revealed two small planets orbiting a star after its red giant phase.

  16. Search for giant planets in M67. III. Excess of hot Jupiters in dense open clusters

    NASA Astrophysics Data System (ADS)

    Brucalassi, A.; Pasquini, L.; Saglia, R.; Ruiz, M. T.; Bonifacio, P.; Leão, I.; Canto Martins, B. L.; de Medeiros, J. R.; Bedin, L. R.; Biazzo, K.; Melo, C.; Lovis, C.; Randich, S.

    2016-07-01

    Since 2008 we used high-precision radial velocity (RV) measurements obtained with different telescopes to detect signatures of massive planets around main-sequence and evolved stars of the open cluster (OC) M67. We aimed to perform a long-term study on giant planet formation in open clusters and determine how this formation depends on stellar mass and chemical composition. A new hot Jupiter (HJ) around the main-sequence star YBP401 is reported in this work. An update of the RV measurements for the two HJ host-stars YBP1194 and YBP1514 is also discussed. Our sample of 66 main-sequence and turnoff stars includes 3 HJs, which indicates a high rate of HJs in this cluster (5.6% for single stars and 4.5%% for the full sample). This rate is much higher than what has been discovered in the field, either with RV surveys or by transits. High metallicity is not a cause for the excess of HJs in M67, nor can the excess be attributed to high stellar masses. When combining this rate with the non-zero eccentricity of the orbits, our results are qualitatively consistent with a HJ formation scenario dominated by strong encounters with other stars or binary companions and subsequent planet-planet scattering, as predicted by N-body simulations. Based on observations collected at the ESO 3.6 m telescope (La Silla), at the 1.93 m telescope of the Observatoire de Haute-Provence (OHP), at the Hobby Eberly Telescope (HET), at the Telescopio Nazionale Galileo (TNG, La Palma) and at the Euler Swiss Telescope.

  17. Final Masses of Giant Planets. II. Jupiter Formation in a Gas-depleted Disk

    NASA Astrophysics Data System (ADS)

    Tanigawa, Takayuki; Tanaka, Hidekazu

    2016-05-01

    First, we study the final masses of giant planets growing in protoplanetary disks through capture of disk gas, by employing empirical formulae for the gas capture rate and a shallow disk gap model, which are both based on hydrodynamic simulations. We find that, for planets less massive than 10 Jupiter masses, their growth rates are mainly controlled by the gas supply through the global disk accretion, and the gap opening does not limit the accretion. The insufficient gas supply compared with the rapid gas capture causes a depletion of the gas surface density even at the outside the gap, which can create an inner hole in the disk. Second, our findings are applied to the formation of our solar system. For the formation of Jupiter, a very low-mass gas disk of several Jupiter masses is required at the beginning of its gas capture because of the continual capture. Such a low-mass gas disk with sufficient solid material can be formed through viscous evolution from a compact disk of initial size ˜10 au. By viscous evolution with a moderate viscosity of α ˜ 10‑3, most of the disk gas accretes onto the Sun and a widely spread low-mass gas disk remains when the solid core of Jupiter starts gas capture at t ˜ 107 yr. A very low-mass gas disk also provides a plausible path where type I and II planetary migrations are both suppressed significantly. In particular, the type II migration of Jupiter-size planets becomes inefficient because of the additional gas depletion due to the rapid gas capture by such planets.

  18. THE McDONALD OBSERVATORY PLANET SEARCH: NEW LONG-PERIOD GIANT PLANETS AND TWO INTERACTING JUPITERS IN THE HD 155358 SYSTEM

    SciTech Connect

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Brugamyer, Erik J.; Barnes, Stuart I.; Caldwell, Caroline; Wittenmyer, Robert A.; Horner, J.; Simon, Attila E.

    2012-04-10

    We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) stars-HD 79498, HD 155358, HD 197037, and HD 220773-taken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see evidence of Keplerian motion caused by the presence of one or more gas giant planets in long-period orbits. We derive orbital parameters for each system and note the properties (composition, activity, etc.) of the host stars. While we have previously announced the two-gas-giant HD 155358 system, we now report a shorter period for planet c. This new period is consistent with the planets being trapped in mutual 2:1 mean-motion resonance. We therefore perform an in-depth stability analysis, placing additional constraints on the orbital parameters of the planets. These results demonstrate the excellent long-term RV stability of the spectrometers on both the Harlan J. Smith 2.7 m telescope and the Hobby-Eberly telescope.

  19. In for the Long Haul: Exploring Atmospheric Cycles on the Giant Planets

    NASA Astrophysics Data System (ADS)

    Fletcher, Leigh N.

    2016-10-01

    Timing is everything. The churning, dynamic atmospheres of the four giant planets exhibit spectacular variability on timescales that are poorly understood, largely due to the challenges involved in acquiring multi-spectral time series over their long, slow orbits. With the notable exception of Cassini, planetary missions rarely provide more than a snapshot of the climate at a particular moment – the vast gaps between spacecraft encounters must be filled by regular Earth-based observations. Archives of infrared observations, essential for characterising the changing environmental conditions in the troposphere and stratosphere (temperatures, winds, composition and clouds), now span three Jovian years, a single Saturnian year, and only one Uranian season. Nevertheless, these have revealed the thermochemical changes associated with Jupiter's belt/zone life cycles (e.g., the 2009-10 fade and revival of the South Equatorial Belt); the seasonal evolution of Saturn's atmosphere (including the 2010 springtime storm) and polar vortices; the rise in storm activity on Uranus, and the development of a seasonal polar vortex on Neptune. Such records are vital for placing the results of new missions (NASA/Juno and ESA/JUICE) in their wider temporal context, and for disentangling the myriad radiative, dynamical and chemical processes shaping gas giant climate. The importance of moist convection has been explored via ground-based infrared observations of large cumulonimbus complexes, surrounded by broad, dry downdrafts, during both Saturn's 2010 storm and Jupiter's 2010 SEB revival. This convection spawns waves that couple the tropospheric weather to the stable stratosphere, generating longitudinal thermal waves or, in the extreme case, Saturn's enormous infrared stratospheric "beacon." But what of the distant ice giants? Long-lived orbital missions, able to provide multi-spectral sounding and in situ sampling of Uranus and/or Neptune, should be a top priority for our community

  20. The giant planets and their satellites: Report on the Cospar Symposium, Ottawa, Canada, May 18-21, 1982

    USGS Publications Warehouse

    Kivelson, M.G.; Behannon, K.W.; Cravens, T.E.; de Pater, I.; Johnson, T.V.; Matson, D.L.; Masursky, H.; Southwood, D.J.; Vasyliunas, V.M.

    1983-01-01

    A Symposium on the Giant Planets and Their Satellites was presented in conjunction with the Twenty-fourth Plenary Meeting of the Committee on Space Research. This paper summarizes the talks presented and places the remaining papers of this volume in context. ?? 1983.

  1. Satellites of giant planets — possible sites for origin and existence of biospheres

    NASA Astrophysics Data System (ADS)

    Simakov, Michael B.

    All giant planets of the Solar system have a big number of satellites (61 of Jupiter, 52 of Saturn, known in 2003). A small part of them consist very large bodies, quite comparable to planets of terrestrial type, but including very significant share of water ice. Some from them have an atmosphere. E.g., the mass of a column of the Titan’s atmosphere exceeds 15 times the mass of the Earth atmosphere column. Formation (or capture) of satellites is a natural phenomenon, and satellite systems definitely should exist at extrasolar planets. As an example, we can see on Titan, the largest satellite of Saturn, which has a dense nitrogen atmosphere and a large quantity of liquid water under ice cover and so has a great exobiological significance. The most recent models of the Titan’s interior lead to the conclusion that a substantial liquid layer exists today under relatively thin ice cover inside Titan. The putative internal water ocean along with complex atmospheric photochemistry provide some exobiological niches on this body: (1) an upper layer of the internal water ocean; (2) pores, veins, channels and pockets filled with brines inside of the lowest part of the icy layer; (3) the places of cryogenic volcanism; (4) set of caves in icy layer connecting with cryovolcanic processes; (5) the brine-filled cracks in icy crust caused by tidal forces; (6) liquid water pools on the surface originated from meteoritic strikes; (7) the sites of hydrothermal activity on the bottom of the ocean. We can see all conditions needed for origin and evolution of biosphere — liquid water, complex organic chemistry and energy sources for support of biological processes — are on the Saturnian moon. Galileo spacecraft has given indications, primarily from magnetometer and gravity data, of the possibility that three of Jupiter’s four large moons, Europa, Ganymede and Callisto have such oceans also. The existing of liquid water ocean within icy world can be consequences of the physical

  2. A SECOND GIANT PLANET IN 3:2 MEAN-MOTION RESONANCE IN THE HD 204313 SYSTEM

    SciTech Connect

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Brugamyer, Erik J.; Barnes, Stuart I.; Caldwell, Caroline; Horner, J.; Wittenmyer, Robert A.; Simon, Attila E.

    2012-07-20

    We present eight years of high-precision radial velocity (RV) data for HD 204313 from the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. The star is known to have a giant planet (Msin i = 3.5 M{sub J} ) on a {approx}1900 day orbit, and a Neptune-mass planet at 0.2 AU. Using our own data in combination with the published CORALIE RVs of Segransan et al., we discover an outer Jovian (Msin i = 1.6 M{sub J} ) planet with P {approx} 2800 days. Our orbital fit suggests that the planets are in a 3:2 mean motion resonance, which would potentially affect their stability. We perform a detailed stability analysis and verify that the planets must be in resonance.

  3. Precise radial velocities of giant stars. IX. HD 59686 Ab: a massive circumstellar planet orbiting a giant star in a 13.6 au eccentric binary system

    NASA Astrophysics Data System (ADS)

    Ortiz, Mauricio; Reffert, Sabine; Trifonov, Trifon; Quirrenbach, Andreas; Mitchell, David S.; Nowak, Grzegorz; Buenzli, Esther; Zimmerman, Neil; Bonnefoy, Mickaël; Skemer, Andy; Defrère, Denis; Lee, Man Hoi; Fischer, Debra A.; Hinz, Philip M.

    2016-10-01

    Context. For over 12 yr, we have carried out a precise radial velocity (RV) survey of a sample of 373 G- and K-giant stars using the Hamilton Échelle Spectrograph at the Lick Observatory. There are, among others, a number of multiple planetary systems in our sample as well as several planetary candidates in stellar binaries. Aims: We aim at detecting and characterizing substellar and stellar companions to the giant star HD 59686 A (HR 2877, HIP 36616). Methods: We obtained high-precision RV measurements of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in the RVs, we can assess the nature of companions in the system. To distinguish between RV variations that are due to non-radial pulsation or stellar spots, we used infrared RVs taken with the CRIRES spectrograph at the Very Large Telescope. Additionally, to characterize the system in more detail, we obtained high-resolution images with LMIRCam at the Large Binocular Telescope. Results: We report the probable discovery of a giant planet with a mass of mp sin i = 6.92-0.24+0.18 MJup orbiting at ap = 1.0860-0.0007+0.0006 au from the giant star HD 59686 A. In addition to the planetary signal, we discovered an eccentric (eB = 0.729-0.003+0.004) binary companion with a mass of mB sin i = 0.5296-0.0008+0.0011 M⊙ orbiting at a close separation from the giant primary with a semi-major axis of aB = 13.56-0.14+0.18 au. Conclusions: The existence of the planet HD 59686 Ab in a tight eccentric binary system severely challenges standard giant planet formation theories and requires substantial improvements to such theories in tight binaries. Otherwise, alternative planet formation scenarios such as second-generation planets or dynamical interactions in an early phase of the system's lifetime need to be seriously considered to better understand the origin of this enigmatic planet. Based on observations collected at the Lick Observatory, University of California.Based on observations collected at the

  4. The First H-band Spectrum of the Giant Planet β Pictoris b

    NASA Astrophysics Data System (ADS)

    Chilcote, Jeffrey; Barman, Travis; Fitzgerald, Michael P.; Graham, James R.; Larkin, James E.; Macintosh, Bruce; Bauman, Brian; Burrows, Adam S.; Cardwell, Andrew; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kalas, Paul; Konopacky, Quinn; Maire, Jérôme; Marchis, Franck; Marley, Mark S.; Marois, Christian; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, Rebecca; Palmer, David; Patience, Jennifer; Perrin, Marshall; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Sivaramakrishnan, Anand; Song, Inseok; Soummer, Rémi; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

    2015-01-01

    Using the recently installed Gemini Planet Imager (GPI), we have obtained the first H-band spectrum of the planetary companion to the nearby young star β Pictoris. GPI is designed to image and provide low-resolution spectra of Jupiter-sized, self-luminous planetary companions around young nearby stars. These observations were taken covering the H band (1.65 μm). The spectrum has a resolving power of ~45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). These values agree well with "hot-start" predictions from planetary evolution models for a gas giant with mass between 10 and 12 M Jup and age between 10 and 20 Myr.

  5. Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra

    NASA Astrophysics Data System (ADS)

    Badman, Sarah V.; Branduardi-Raymont, Graziella; Galand, Marina; Hess, Sébastien L. G.; Krupp, Norbert; Lamy, Laurent; Melin, Henrik; Tao, Chihiro

    2015-04-01

    The ionospheric response to auroral precipitation at the giant planets is reviewed, using models and observations. The emission processes for aurorae at radio, infrared, visible, ultraviolet, and X-ray wavelengths are described, and exemplified using ground- and space-based observations. Comparisons between the emissions at different wavelengths are made, where possible, and interpreted in terms of precipitating particle characteristics or atmospheric conditions. Finally, the spatial distributions and dynamics of the various components of the aurorae (moon footprints, low-latitude, main oval, polar) are related to magnetospheric processes and boundaries, using theory, in situ, and remote observations, with the aim of distinguishing between those related to internally-driven dynamics, and those related to the solar wind interaction.

  6. Seismology with a Fourier-transform spectrometer: applications to giant planets and stars.

    PubMed

    Maillard, J P

    1996-06-01

    A method to detect the acoustic oscillation spectrum of giant planets and stars exploits the multiplex properties of a Fourier-transform spectrometer (FTS). It is based on measurement of the small Doppler shift related to the oscillation of the atmosphere measured from all the lines in a portion of the planetary or the stellar spectrum directly from the interferogram. The resulting amplitude modulation of the output signal is recorded continuously over several consecutive nights at a fixed path difference selected from criteria of optimum efficiency. Hence the Fourier transform of this signal yields the pressure-mode spectrum of the object. Applications to Jupiter, Saturn, and Procyon, observed in this mode with the step-scan FTS installed in the Canada-France-Hawaii Telescope, are presented. Future projects are discussed.

  7. THE FIRST H-BAND SPECTRUM OF THE GIANT PLANET β PICTORIS b

    SciTech Connect

    Chilcote, Jeffrey; Fitzgerald, Michael P.; Larkin, James E.; Barman, Travis; Graham, James R.; Kalas, Paul; Macintosh, Bruce; Ingraham, Patrick; Bauman, Brian; Burrows, Adam S.; Cardwell, Andrew; Hartung, Markus; Hibon, Pascale; De Rosa, Robert J.; Dillon, Daren; Gavel, Donald; Dunn, Jennifer; Erikson, Darren; Goodsell, Stephen J.; and others

    2015-01-01

    Using the recently installed Gemini Planet Imager (GPI), we have obtained the first H-band spectrum of the planetary companion to the nearby young star β Pictoris. GPI is designed to image and provide low-resolution spectra of Jupiter-sized, self-luminous planetary companions around young nearby stars. These observations were taken covering the H band (1.65 μm). The spectrum has a resolving power of ∼45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). These values agree well with ''hot-start'' predictions from planetary evolution models for a gas giant with mass between 10 and 12 M {sub Jup} and age between 10 and 20 Myr.

  8. Superionic and metallic states of water and ammonia at giant planet conditions.

    PubMed

    Cavazzoni, C; Chiarotti, G L; Scandolo, S; Tosatti, E; Bernasconi, M; Parrinello, M

    1999-01-01

    The phase diagrams of water and ammonia were determined by constant pressure ab initio molecular dynamic simulations at pressures (30 to 300 gigapascal) and temperatures (300 to 7000 kelvin) of relevance for the middle ice layers of the giant planets Neptune and Uranus. Along the planetary isentrope water and ammonia behave as fully dissociated ionic, electronically insulating fluid phases, which turn metallic at temperatures exceeding 7000 kelvin for water and 5500 kelvin for ammonia. At lower temperatures, the phase diagrams of water and ammonia exhibit a superionic solid phase between the solid and the ionic liquid. These simulations improve our understanding of the properties of the middle ice layers of Neptune and Uranus. PMID:9872734

  9. Low-Temperature Hydrocarbon Photochemistry: CH3 + CH3 Recombination in Giant Planet Atmospheres

    NASA Technical Reports Server (NTRS)

    Smith, Gregory P.; Huestis, David L.

    2002-01-01

    Planetary emissions of the methyl radical CH3 were observed for the first time in 1998 on Saturn and Neptune by the ISO (Infrared Space Observatory) mission satellite. CH3 is produced by VUV photolysis of CH4 and is the key photochemical intermediate leading complex organic molecules on the giant planets and moons. The CH3 emissions from Saturn were unexpectedly weak. A suggested remedy is to increase the rate of the recombination reaction CH3 + CH3 + H2 --> C2H6 + H2 at 140 K to a value at least 10 times that measured at room temperature in rare gases, but within the range of disagreeing theoretical expressions at low temperature. We are performing laboratory experiments at low temperature and very low pressure. The experiments are supported by RRKM theoretical modeling that is calibrated using the extensive combustion literature.

  10. Small hydrocarbon molecules in cloud-forming brown dwarf and giant gas planet atmospheres

    NASA Astrophysics Data System (ADS)

    Bilger, C.; Rimmer, P.; Helling, Ch.

    2013-11-01

    We study the abundances of complex carbon-bearing molecules in the oxygen-rich dust-forming atmospheres of brown dwarfs and giant gas planets. The inner atmospheric regions that form the inner boundary for thermochemical gas-phase models are investigated. Results from DRIFT-PHOENIX atmosphere simulations, which include the feedback of phase-non-equilibrium dust cloud formation on the atmospheric structure and the gas-phase abundances, are utilized. The resulting element depletion leads to a shift in the carbon-to-oxygen ratio such that several hydrocarbon molecules and cyanopolyyne molecules can be present. An increase in surface gravity and/or a decrease in metallicity support the increase in the partial pressures of these species. CO, CO2, CH4 and HCN contain the largest fraction of carbon. In the upper atmosphere of low-metallicity objects, more carbon is contained in C4H than in CO, and also CH3 and C2H2 play an increasingly important role as carbon sink. We determine chemical relaxation time-scales to evaluate if hydrocarbon molecules can be affected by transport-induced quenching. Our results suggest that a considerable amount of C2H6 and C2H2 could be expected in the upper atmospheres not only of giant gas planets, but also of brown dwarfs. However, the exact quenching height strongly depends on the data source used. These results will have an impact on future thermokinetic studies, as they change the inner boundary condition for those simulations.

  11. AB initio free energy calculations of the solubility of silica in metallic hydrogen and application to giant planet cores

    SciTech Connect

    González-Cataldo, F.; Wilson, Hugh F.; Militzer, B.

    2014-05-20

    By combining density functional molecular dynamics simulations with a thermodynamic integration technique, we determine the free energy of metallic hydrogen and silica, SiO{sub 2}, at megabar pressures and thousands of degrees Kelvin. Our ab initio solubility calculations show that silica dissolves into fluid hydrogen above 5000 K for pressures from 10 and 40 Mbars, which has implications for the evolution of rocky cores in giant gas planets like Jupiter, Saturn, and a substantial fraction of known extrasolar planets. Our findings underline the necessity of considering the erosion and redistribution of core materials in giant planet evolution models, but they also demonstrate that hot metallic hydrogen is a good solvent at megabar pressures, which has implications for high-pressure experiments.

  12. Kepler-432 b: a massive planet in a highly eccentric orbit transiting a red giant

    NASA Astrophysics Data System (ADS)

    Ciceri, S.; Lillo-Box, J.; Southworth, J.; Mancini, L.; Henning, Th.; Barrado, D.

    2015-01-01

    We report the first disclosure of the planetary nature of Kepler-432 b (aka Kepler object of interest KOI-1299.01). We accurately constrained its mass and eccentricity by high-precision radial velocity measurements obtained with the CAFE spectrograph at the CAHA 2.2-m telescope. By simultaneously fitting these new data and Kepler photometry, we found that Kepler-432 b is a dense transiting exoplanet with a mass of Mp = 4.87 ± 0.48MJup and radius of Rp = 1.120 ± 0.036RJup. The planet revolves every 52.5 d around a K giant star that ascends the red giant branch, and it moves on a highly eccentric orbit with e = 0.535 ± 0.030. By analysing two near-IR high-resolution images, we found that a star is located at 1.1'' from Kepler-432, but it is too faint to cause significant effects on the transit depth. Together with Kepler-56 and Kepler-91, Kepler-432 occupies an almost-desert region of parameter space, which is important for constraining the evolutionary processes of planetary systems. RV data (Table A.1) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/L5

  13. Dynamics of the envelope of a rapidly rotating star or giant planet in gravitational contraction

    NASA Astrophysics Data System (ADS)

    Hypolite, D.; Rieutord, M.

    2014-12-01

    Aims: We wish to understand the processes that control the fluid flows of a gravitationally contracting and rotating star or giant planet. Methods: We consider a spherical shell containing an incompressible fluid that is slowly absorbed by the core so as to mimic gravitational contraction. We also consider the effects of a stable stratification that may modify the dynamics of a pre-main-sequence star of intermediate mass. Results: This simple model reveals the importance of both the Stewartson layer attached to the core and the boundary conditions met by the fluid at the surface of the object. In the case of a pre-main-sequence star of intermediate mass where the envelope is stably stratified, shortly after the birth line, the spin-up flow driven by contraction overwhelms the baroclinic flow that would take place otherwise. This model also shows that for a contracting envelope, a self-similar flow of growing amplitude controls the dynamics. It suggests that initial conditions on the birth line are most probably forgotten. Finally, the model shows that the shear (Stewartson) layer that lies on the tangent cylinder of the core is likely a key feature of the dynamics that is missing in 1D models. This layer can explain the core and envelope rotational coupling that is required to explain the slow rotation of cores in giant and subgiant stars.

  14. Gap formation in a self-gravitating disk and the associated migration of the embedded giant planet

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Liu, Hui-Gen; Zhou, Ji-Lin; Wittenmyer, Robert A.

    2014-04-01

    We present the results of our recent study on the interactions between a giant planet and a self-gravitating gas disk. We investigate how the disk's self-gravity affects the gap formation process and the migration of the giant planet. Two series of 1-D and 2-D hydrodynamic simulations are performed. We select several surface densities and focus on the gravitationally stable region. To obtain more reliable gravity torques exerted on the planet, a refined treatment of the disk's gravity is adopted in the vicinity of the planet. Our results indicate that the net effect of the disk's self-gravity on the gap formation process depends on the surface density of the disk. We notice that there are two critical values, ΣI and ΣII. When the surface density of the disk is lower than the first one, Σ0 < ΣI, the effect of self-gravity suppresses the formation of a gap. When Σ0 > ΣI, the self-gravity of the gas tends to benefit the gap formation process and enlarges the width/depth of the gap. According to our 1-D and 2-D simulations, we estimate the first critical surface density to be ΣI ≈ 0.8 MMSN. This effect increases until the surface density reaches the second critical value ΣII. When Σ0 > ΣII, the gravitational turbulence in the disk becomes dominant and the gap formation process is suppressed again. Our 2-D simulations show that this critical surface density is around 3.5 MMSN. We also study the associated orbital evolution of a giant planet. Under the effect of the disk's self-gravity, the migration rate of the giant planet increases when the disk is dominated by gravitational turbulence. We show that the migration timescale correlates with the effective viscosity and can be up to 104 yr.

  15. External supply of oxygen to the atmospheres of the giant planets.

    PubMed

    Feuchtgruber, H; Lellouch, E; de Graauw, T; Bézard, B; Encrenaz, T; Griffin, M

    1997-09-11

    The atmospheres of the giant planets are reducing, being mainly composed of hydrogen, helium and methane. But the rings and icy satellites that surround these planets, together with the flux of interplanetary dust, could act as important sources of oxygen, which would be delivered to the atmospheres mainly in the form of water ice or silicate dust. Here we report the detection, by infrared spectroscopy, of gaseous H2O in the upper atmospheres of Saturn, Uranus and Neptune. The implied H2O column densities are 1.5 x 10(15), 9 x 10(13) and 3 x 10(14) molecules cm(-2) respectively. CO2 in comparable amounts was also detected in the atmospheres of Saturn and Neptune. These observations can be accounted for by external fluxes of 10(5)-10(7) H2O molecules cm(-2) s(-1) and subsequent chemical processing in the atmospheres. The presence of gaseous water and infalling dust will affect the photochemistry, energy budget and ionospheric properties of these atmospheres. Moreover, our findings may help to constrain the injection rate and possible activity of distant icy objects in the Solar System. PMID:9296492

  16. External supply of oxygen to the atmospheres of the giant planets.

    PubMed

    Feuchtgruber, H; Lellouch, E; de Graauw, T; Bézard, B; Encrenaz, T; Griffin, M

    1997-09-11

    The atmospheres of the giant planets are reducing, being mainly composed of hydrogen, helium and methane. But the rings and icy satellites that surround these planets, together with the flux of interplanetary dust, could act as important sources of oxygen, which would be delivered to the atmospheres mainly in the form of water ice or silicate dust. Here we report the detection, by infrared spectroscopy, of gaseous H2O in the upper atmospheres of Saturn, Uranus and Neptune. The implied H2O column densities are 1.5 x 10(15), 9 x 10(13) and 3 x 10(14) molecules cm(-2) respectively. CO2 in comparable amounts was also detected in the atmospheres of Saturn and Neptune. These observations can be accounted for by external fluxes of 10(5)-10(7) H2O molecules cm(-2) s(-1) and subsequent chemical processing in the atmospheres. The presence of gaseous water and infalling dust will affect the photochemistry, energy budget and ionospheric properties of these atmospheres. Moreover, our findings may help to constrain the injection rate and possible activity of distant icy objects in the Solar System.

  17. PLANETARY CORE FORMATION WITH COLLISIONAL FRAGMENTATION AND ATMOSPHERE TO FORM GAS GIANT PLANETS

    SciTech Connect

    Kobayashi, Hiroshi; Krivov, Alexander V.; Tanaka, Hidekazu

    2011-09-01

    Massive planetary cores ({approx}10 Earth masses) trigger rapid gas accretion to form gas giant planets such as Jupiter and Saturn. We investigate the core growth and the possibilities for cores to reach such a critical core mass. At the late stage, planetary cores grow through collisions with small planetesimals. Collisional fragmentation of planetesimals, which is induced by gravitational interaction with planetary cores, reduces the amount of planetesimals surrounding them, and thus the final core masses. Starting from small planetesimals that the fragmentation rapidly removes, less massive cores are formed. However, planetary cores acquire atmospheres that enlarge their collisional cross section before rapid gas accretion. Once planetary cores exceed about Mars mass, atmospheres significantly accelerate the growth of cores. We show that, taking into account the effects of fragmentation and atmosphere, initially large planetesimals enable formation of sufficiently massive cores. On the other hand, because the growth of cores is slow for large planetesimals, a massive disk is necessary for cores to grow enough within a disk lifetime. If the disk with 100 km sized initial planetesimals is 10 times as massive as the minimum mass solar nebula, planetary cores can exceed 10 Earth masses in the Jovian planet region (>5 AU).

  18. CAN TiO EXPLAIN THERMAL INVERSIONS IN THE UPPER ATMOSPHERES OF IRRADIATED GIANT PLANETS?

    SciTech Connect

    Spiegel, David S.; Silverio, Katie; Burrows, Adam E-mail: silverio@astro.princeton.edu

    2009-07-10

    Spitzer Space Telescope infrared observations indicate that several transiting extrasolar giant planets have thermal inversions in their upper atmospheres. Above a relative minimum, the temperature appears to increase with altitude. Such an inversion probably requires a species at high altitude that absorbs a significant amount of incident optical/UV radiation. Some authors have suggested that the strong optical absorbers titanium oxide (TiO) and vanadium oxide (VO) could provide the needed additional opacity, but if regions of the atmosphere are cold enough for Ti and V to be sequestered into solids they might rain out and be severely depleted. With a model of the vertical distribution of a refractory species in gaseous and condensed form, we address the question of whether enough TiO (or VO) could survive aloft in an irradiated planet's atmosphere to produce a thermal inversion. We find that it is unlikely that VO could play a critical role in producing thermal inversions. Furthermore, we find that macroscopic mixing is essential to the TiO hypothesis; without macroscopic mixing, such a heavy species cannot persist in a planet's upper atmosphere. The amount of macroscopic mixing that is required depends on the size of condensed titanium-bearing particles that form in regions of an atmosphere that are too cold for gaseous TiO to exist. We parameterize the macroscopic mixing with the eddy diffusion coefficient K{sub zz} and find, as a function of particle size a, the values that K{sub zz} must assume on the highly irradiated planets HD 209458b, HD 149026b, TrES-4, and OGLE-TR-56b to loft enough titanium to the upper atmosphere for the TiO hypothesis to be correct. On these planets, we find that for TiO to be responsible for thermal inversions K{sub zz} must be at least a few times 10{sup 7} cm{sup 2} s{sup -1}, even for a = 0.1 {mu}m, and increases to nearly 10{sup 11} cm{sup 2} s{sup -1} for a = 10 {mu}m. Such large values may be problematic for the TiO hypothesis

  19. Astrometric detection of giant planets around nearby M dwarfs: the Gaia potential

    NASA Astrophysics Data System (ADS)

    Sozzetti, A.; Giacobbe, P.; Lattanzi, M. G.; Micela, G.; Morbidelli, R.; Tinetti, G.

    2014-01-01

    Cool M dwarfs within a few tens of parsecs from the Sun are becoming the focus of dedicated observational programs in the realm of exoplanet astrophysics. Gaia, in its all-sky survey of >109 objects, will deliver precision astrometry for a magnitude-limited (V = 20) sample of M dwarfs. We investigate some aspects of the synergy between the Gaia astrometric data on nearby M dwarfs and other ground-based and space-borne programs for planet detection and characterization. We carry out numerical simulations to gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of known dM stars within ˜30 pc from the Sun. We express Gaia detection thresholds as a function of system parameters and in view of the latest mission profile, including the most up-to-date astrometric error model. Our major findings are as follows: (1) it will be possible to accurately determine orbits and masses for Jupiter-mass planets with orbital periods in the range 0.2 ≲ P ≲ 6.0 yr and with an astrometric signal-to-noise ratio ς/σAL ≳ 10. Given present-day estimates of the planet fraction fp around M dwarfs, ≈102 giant planets could be found by Gaia around the sample. Comprehensive screening by Gaia of the reservoir of ˜4 × 105 M dwarfs within 100 pc could result in ˜2600 detections and as many as ˜500 accurate orbit determinations. The value of fp could then be determined with an accuracy of 2 per cent, an improvement by over an order of magnitude with respect to the most precise values available to-date; (2) in the same period range, inclination angles corresponding to quasi-edge-on configurations will be determined with enough precision (a few per cent) so that it will be possible to identify intermediate-separation planets which are potentially transiting within the errors. Gaia could alert us of the existence of 10 such systems. More than 250 candidates could be identified assuming solutions compatible with transit configurations within 10 per cent

  20. Close encounters between Chariklo and the giant planets: What about the rings?

    NASA Astrophysics Data System (ADS)

    Winter, Othon; Araujo, Rosana; Sfair, Rafael

    2015-08-01

    It is known that the Centaurs are subject to close gravitational encounters with the giant planets along their mean lifetime (10 Myrs). Thus, in the present work, we investigate the stability of the rings of Chariklo when perturbed by such encounters. Chariklo is a Centaur with semi-major axis a=15.8 AU, eccentricity e=0.175, orbital inclination I=23.4º, and with a physical radius of 124 km. The two narrow rings around Chariklo are in the equatorial plane and have circular orbits, with the orbital radii of 391 km and 405 km. The method consisted on numerically integrate for 100 Myrs a system composed by the Sun, the eight planets, and a sample of 729 objects with the same mass and radius of Chariklo, but with small deviations in the orbital elements a, e and I. All encounters of those clones within 1 Hill's radius of each planet were recorded. We found that the majority of the encounters (48.0%) happens with Uranus, 26.0% with Saturn, 16.6% with Jupiter and 9.4% with Neptune. From these encounters we selected those that take place within ten times the rupture radius to study the effect upon particles around Chariklo. The particles were distributed from 200 km to 1000 km, in equatorial and circular orbits, with a random angular distribution. We found that the effects due to the encounters with Uranus and Neptune are negligible on the dynamics of the particles, i.e., no particles are lost and the rings are not significantly disturbed. However, for Jupiter and Saturn there are some encounters able to completely remove the rings. We also analyze the variations in semi-major axis and eccentricity of the particles that compose the rings, due to the close planetary encounters. We will present a complete analysis of the characteristics and frequency of each kind of event.

  1. Methane, carbon monoxide, and ammonia in brown dwarfs and self-luminous giant planets

    SciTech Connect

    Zahnle, Kevin J.; Marley, Mark S. E-mail: Mark.S.Marley@NASA.gov

    2014-12-10

    We address disequilibrium abundances of some simple molecules in the atmospheres of solar composition brown dwarfs and self-luminous extrasolar giant planets using a kinetics-based one-dimensional atmospheric chemistry model. Our approach is to use the full kinetics model to survey the parameter space with effective temperatures between 500 K and 1100 K. In all of these worlds, equilibrium chemistry favors CH{sub 4} over CO in the parts of the atmosphere that can be seen from Earth, but in most disequilibrium favors CO. The small surface gravity of a planet strongly discriminates against CH{sub 4} when compared to an otherwise comparable brown dwarf. If vertical mixing is like Jupiter's, the transition from methane to CO occurs at 500 K in a planet. Sluggish vertical mixing can raise this to 600 K, but clouds or more vigorous vertical mixing could lower this to 400 K. The comparable thresholds in brown dwarfs are 1100 ± 100 K. Ammonia is also sensitive to gravity, but, unlike CH{sub 4}/CO, the NH{sub 3}/N{sub 2} ratio is insensitive to mixing, which makes NH{sub 3} a potential proxy for gravity. HCN may become interesting in high-gravity brown dwarfs with very strong vertical mixing. Detailed analysis of the CO-CH{sub 4} reaction network reveals that the bottleneck to CO hydrogenation goes through methanol, in partial agreement with previous work. Simple, easy to use quenching relations are derived by fitting to the complete chemistry of the full ensemble of models. These relations are valid for determining CO, CH{sub 4}, NH{sub 3}, HCN, and CO{sub 2} abundances in the range of self-luminous worlds we have studied, but may not apply if atmospheres are strongly heated at high altitudes by processes not considered here (e.g., wave breaking).

  2. Grain Growth and Settling: An Implication for Disk Instability and Giant Planet Formation

    NASA Astrophysics Data System (ADS)

    Sengupta, Debanjan; Dodson-Robinson, Sarah

    2016-10-01

    Formation of super-massive planets at a distance ranging from around 5 to 20 AU cannot be adequately explained by core accretion, even in the most optimistic scenario. The only promising alternative is the fragmentation mechanism in which giant planets are formed directly from the contraction of a clump of gas produced by gravitational instability. Here, we investigate whether simultaneous grain growth and settling can trigger gravitational instability at these distances. We study the physics of grain growth and how grains of different sizes are subject to sedimentation using a sophisticated collision and settling model starting with an MRN dust size distribution consistent with that of ISM. We capture the full physics of disk turbulence, dust diffusion and vertical settling, followed by a wavelength dependent opacity calculation including constant porosity. The thermal profile of the disk is re-calculated frequently with a detailed radiative transfer code RadMC. More importantly, our aim is to check whether grain growth and dust settling can effectively change the opacity for the gas and affect the stability of the disk by changing the ToomreQ parameter. We take a prototype disk which is hot on the surface and has a quiescent midplane, which, because of being less turbulent allows the grains to grow more efficiently. In this context, we examine the gravitational stability of a layered accretion disk experiencing dust-settling and review the possibilities of super-massive planet formation at the range of distances concerned. We also present a steady state grain abundance and the opacity profile at different time of disk evolution. We compare that with the standard viscous accretion disk.

  3. Methane, Carbon Monoxide, and Ammonia in Brown Dwarfs and Self-Luminous Giant Planets

    NASA Astrophysics Data System (ADS)

    Zahnle, Kevin J.; Marley, Mark S.

    2014-12-01

    We address disequilibrium abundances of some simple molecules in the atmospheres of solar composition brown dwarfs and self-luminous extrasolar giant planets using a kinetics-based one-dimensional atmospheric chemistry model. Our approach is to use the full kinetics model to survey the parameter space with effective temperatures between 500 K and 1100 K. In all of these worlds, equilibrium chemistry favors CH4 over CO in the parts of the atmosphere that can be seen from Earth, but in most disequilibrium favors CO. The small surface gravity of a planet strongly discriminates against CH4 when compared to an otherwise comparable brown dwarf. If vertical mixing is like Jupiter's, the transition from methane to CO occurs at 500 K in a planet. Sluggish vertical mixing can raise this to 600 K, but clouds or more vigorous vertical mixing could lower this to 400 K. The comparable thresholds in brown dwarfs are 1100 ± 100 K. Ammonia is also sensitive to gravity, but, unlike CH4/CO, the NH3/N2 ratio is insensitive to mixing, which makes NH3 a potential proxy for gravity. HCN may become interesting in high-gravity brown dwarfs with very strong vertical mixing. Detailed analysis of the CO-CH4 reaction network reveals that the bottleneck to CO hydrogenation goes through methanol, in partial agreement with previous work. Simple, easy to use quenching relations are derived by fitting to the complete chemistry of the full ensemble of models. These relations are valid for determining CO, CH4, NH3, HCN, and CO2 abundances in the range of self-luminous worlds we have studied, but may not apply if atmospheres are strongly heated at high altitudes by processes not considered here (e.g., wave breaking).

  4. MODELING THE FORMATION OF GIANT PLANET CORES. I. EVALUATING KEY PROCESSES

    SciTech Connect

    Levison, Harold F.; Thommes, Edward; Duncan, Martin J.

    2010-04-15

    One of the most challenging problems we face in our understanding of planet formation is how Jupiter and Saturn could have formed before the solar nebula dispersed. The most popular model of giant planet formation is the so-called core accretion model. In this model a large planetary embryo formed first, mainly by two-body accretion. This is then followed by a period of inflow of nebular gas directly onto the growing planet. The core accretion model has an Achilles heel, namely the very first step. We have undertaken the most comprehensive study of this process to date. In this study, we numerically integrate the orbits of a number of planetary embryos embedded in a swarm of planetesimals. In these experiments, we have included a large number of physical processes that might enhance accretion. In particular, we have included (1) aerodynamic gas drag, (2) collisional damping between planetesimals, (3) enhanced embryo cross sections due to their atmospheres, (4) planetesimal fragmentation, and (5) planetesimal-driven migration. We find that the gravitational interaction between the embryos and the planetesimals leads to the wholesale redistribution of material-regions are cleared of material and gaps open near the embryos. Indeed, in 90% of our simulations without fragmentation, the region near those embryos is cleared of planetesimals before much growth can occur. Thus, the widely used assumption that the surface density distribution of planetesimals is smooth can lead to misleading results. In the remaining 10% of our simulations, the embryos undergo a burst of outward migration that significantly increases growth. On timescales of {approx}10{sup 5} years, the outer embryo can migrate {approx}6 AU and grow to roughly 30 M {sub +}. This represents a largely unexplored mode of core formation. We also find that the inclusion of planetesimal fragmentation tends to inhibit growth except for a narrow range of fragment migration rates.

  5. Magnitude and timing of the giant planet instability: A reassessment from the perspective of the asteroid belt

    NASA Astrophysics Data System (ADS)

    Toliou, A.; Morbidelli, A.; Tsiganis, K.

    2016-07-01

    It is generally accepted today that our solar system has undergone a phase during which the orbits of the giant planets became very unstable. In recent years, many studies have identified traces of this event and have provided reasonable justification for this occurrence. The magnitude (in terms of orbital variation) and the timing of the instability though (early or late with respect to the dispersal of the gas disk) still remains an open debate. The terrestrial planets seem to set a strict constraint: either the giant planet instability happened early, while the terrestrial planets were still forming, or the orbits of Jupiter and Saturn had to separate from each other impulsively, with a large enough "jump" in semimajor axis for the terrestrial planets to remain stable. Because a large orbital jump is a low probability event, the early instability hypothesis seems to be favored, however, the asteroid belt would also evolve in a different way, assuming different instability amplitudes. These two constraints need to match each other in order to favor one scenario over the other. Considering an initially dynamically cold disk of asteroids, previous studies concluded that a comparably large jump is needed to reconstruct the current asteroid belt. Here we confirm the same conclusion, but considering an asteroid population already strongly excited in eccentricity, such as that produced in the Grand Tack scenario. Because the asteroids existed since the time of removal of the gas disk, unlike the terrestrial planets, this constraint on the width of the giant planet jump is valid regardless of whether the instability happened early or late. Hence, at this stage, assuming an early instability does not appear to provide any advantage in terms of the probabilistic reconstruction of the solar system structure.

  6. The first H-band spectrum of the giant planet β Pictoris b [THE FIRST H-BAND SPECTRUM OF THE MASSIVE GAS GIANT PLANET BETA PICTORIS b WITH THE GEMINI PLANET IMAGER

    SciTech Connect

    Chilcote, Jeffrey; Barman, Travis; Fitzgerald, Michael P.; Graham, James R.; Larkin, James E.; Macintosh, Bruce; Bauman, Brian; Burrows, Adam S.; Cardwell, Andrew; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kalas, Paul; Konopacky, Quinn; Maire, Jérôme; Marchis, Franck; Marley, Mark S.; Marois, Christian; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, Rebecca; Palmer, David; Patience, Jennifer; Perrin, Marshall; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Sivaramakrishnan, Anand; Song, Inseok; Soummer, Rémi; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

    2014-12-12

    Using the recently installed Gemini Planet Imager (GPI), we have obtained the first H-band spectrum of the planetary companion to the nearby young star β Pictoris. GPI is designed to image and provide low-resolution spectra of Jupiter-sized, self-luminous planetary companions around young nearby stars. These observations were taken covering the H band (1.65 μm). The spectrum has a resolving power of ~45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). These values agree well with "hot-start" predictions from planetary evolution models for a gas giant with mass between 10 and 12 MJup and age between 10 and 20 Myr.

  7. Study of the impact of the post-MS evolution of the host star on the orbits of close-in planets. II. A giant planet in a close-in orbit around the RGB star HIP 63242

    NASA Astrophysics Data System (ADS)

    Jones, M. I.; Jenkins, J. S.; Rojo, P.; Melo, C. H. F.; Bluhm, P.

    2013-08-01

    Context. More than 40 planets have been found around giant stars, revealing a lack of systems orbiting interior to ~0.6 AU. This observational fact contrasts with the planetary population around solar-type stars and has been interpreted as the result of the orbital evolution of planets through the interaction with the host star and/or because of a different formation/migration scenario of planets around more massive stars. Aims: We are conducting a radial velocity study of a sample of 166 giant stars aimed at studying the population of close-in planets orbiting post-main sequence stars. Methods: We computed precision radial velocities from multi-epoch spectroscopic data to search for planets around giant stars. Results: We present the discovery of a massive planet around the intermediate-mass giant star HIP 63242. The best Keplerian fit to the data leads to an orbital distance of 0.57 AU, an eccentricity of 0.23 and a projected mass of 9.2 MJ. HIP 63242 b is the innermost planet detected around any intermediate-mass giant star and also the first planet detected in our survey. Based on observations collected at La Silla - Paranal Observatory under programs ID's 085.C-0557, 087.C.0476, 089.C-0524, and 090.C-0345.

  8. The effect of Dead Zones on the Gas Accretion of a Giant Planet

    NASA Astrophysics Data System (ADS)

    D'Angelo, Gennaro; Marzari, Francesco

    Giant planets undergo a phase of run-away gas accretion, during and beyond which the accretion rate (dMp/dt) is dictated by the ability of the protoplanetary disk to provide gas to the planet's vicinity (Lissauer et al. 2009). Once the planet's Hill radius exceeds the disk scale height, a disk forms around the planet (Kley 1999; Lubow et al. 1999). This circumplanetary disk (or CPD) is often identified as a standard accretion disk, and physical processes believed to be at work in accretion disks are sometimes thought to operate in CPDs. In particular, it has been proposed that turbulence within a CPD is driven by magneto-rotational instability (MRI), and that MRI-inactive regions (or Dead Zones) may be present in the disk's mid-plane due to poor ionization of the gas (Lubow and Martin 2012; Turner et al. 2014). The presence of a Dead Zone may affect accretion through a CPD, if most of the mass is transported along the disk's mid-plane (Rivier et al. 2012). However, 3D calculations of viscous CPDs indicate that accretion occurs predominantly at and above the CPD surface (D'Angelo et al. 2003; Bate et al. 2003; Tanigawa et al. 2012; Ayliffe and Bate 2012; Gressel et al. 2013), i.e., in regions that are generally expected to be MRI-active (Turner et al. 2014). To asses the impact on dMp/dt of the presence of Dead Zones in CPDs, we perform 3D global hydrodynamics calculations of a Jupiter-mass planet embedded in a protoplanetary disk. The CPD is resolved by means of multiple nested grids at the length scale of 0.6 Jupiter radii (Rj). We apply a local-isothermal equation of state and assume that the kinematic viscosity is constant throughout, at a level of 1e-5 a(2) Omega (a is the planet's orbital radius and Omega its frequency). To mimic the presence of a MRI-inactive region in the CPD, we modify the local viscosity so that its value is reduced by a factor of 1000 within about 60Rj of the planet. This Dead Zone extends above and below the CPD mid-plane for a few (CPD

  9. EUV-driven ionospheres and electron transport on extrasolar giant planets orbiting active stars

    NASA Astrophysics Data System (ADS)

    Chadney, J. M.; Galand, M.; Koskinen, T. T.; Miller, S.; Sanz-Forcada, J.; Unruh, Y. C.; Yelle, R. V.

    2016-03-01

    The composition and structure of the upper atmospheres of extrasolar giant planets (EGPs) are affected by the high-energy spectrum of their host stars from soft X-rays to the extreme ultraviolet (EUV). This emission depends on the activity level of the star, which is primarily determined by its age. In this study, we focus upon EGPs orbiting K- and M-dwarf stars of different ages - ɛ Eridani, AD Leonis, AU Microscopii - and the Sun. X-ray and EUV (XUV) spectra for these stars are constructed using a coronal model. These spectra are used to drive both a thermospheric model and an ionospheric model, providing densities of neutral and ion species. Ionisation - as a result of stellar radiation deposition - is included through photo-ionisation and electron-impact processes. The former is calculated by solving the Lambert-Beer law, while the latter is calculated from a supra-thermal electron transport model. We find that EGP ionospheres at all orbital distances considered (0.1-1 AU) and around all stars selected are dominated by the long-lived H+ ion. In addition, planets with upper atmospheres where H2 is not substantially dissociated (at large orbital distances) have a layer in which H3+ is the major ion at the base of the ionosphere. For fast-rotating planets, densities of short-lived H3+ undergo significant diurnal variations, with the maximum value being driven by the stellar X-ray flux. In contrast, densities of longer-lived H+ show very little day/night variability and the magnitude is driven by the level of stellar EUV flux. The H3+ peak in EGPs with upper atmospheres where H2 is dissociated (orbiting close to their star) under strong stellar illumination is pushed to altitudes below the homopause, where this ion is likely to be destroyed through reactions with heavy species (e.g. hydrocarbons, water). The inclusion of secondary ionisation processes produces significantly enhanced ion and electron densities at altitudes below the main EUV ionisation peak, as

  10. KEPLER-68: THREE PLANETS, ONE WITH A DENSITY BETWEEN THAT OF EARTH AND ICE GIANTS

    SciTech Connect

    Gilliland, Ronald L.; Marcy, Geoffrey W.; Isaacson, Howard; Rowe, Jason F.; Henze, Christopher E.; Lissauer, Jack J.; Rogers, Leslie; Torres, Guillermo; Fressin, Francois; Desert, Jean-Michel; Lopez, Eric D.; Buchhave, Lars A.; Christensen-Dalsgaard, Jorgen; Handberg, Rasmus; Jenkins, Jon M.; Basu, Sarbani; Metcalfe, Travis S.; Hekker, Saskia; and others

    2013-03-20

    NASA's Kepler Mission has revealed two transiting planets orbiting Kepler-68. Follow-up Doppler measurements have established the mass of the innermost planet and revealed a third Jovian-mass planet orbiting beyond the two transiting planets. Kepler-68b, in a 5.4 day orbit, has M{sub P}=8.3{sup +2.2}{sub -2.4} M{sub Circled-Plus }, R{sub P}=2.31{sup +0.06}{sub -0.09} R{sub Circled-Plus }, and {rho}{sub P}=3.32{sup +0.86}{sub -0.98} g cm{sup -3}, giving Kepler-68b a density intermediate between that of the ice giants and Earth. Kepler-68c is Earth-sized, with a radius R{sub P}=0.953{sup +0.037}{sub -0.042} R{sub Circled-Plus} and transits on a 9.6 day orbit; validation of Kepler-68c posed unique challenges. Kepler-68d has an orbital period of 580 {+-} 15 days and a minimum mass of M{sub P}sin i = 0.947 {+-} 0.035M{sub J} . Power spectra of the Kepler photometry at one minute cadence exhibit a rich and strong set of asteroseismic pulsation modes enabling detailed analysis of the stellar interior. Spectroscopy of the star coupled with asteroseismic modeling of the multiple pulsation modes yield precise measurements of stellar properties, notably T{sub eff} = 5793 {+-} 74 K, M{sub *} = 1.079 {+-} 0.051 M{sub Sun }, R{sub *} = 1.243 {+-} 0.019 R{sub Sun }, and {rho}{sub *} = 0.7903 {+-} 0.0054 g cm{sup -3}, all measured with fractional uncertainties of only a few percent. Models of Kepler-68b suggest that it is likely composed of rock and water, or has a H and He envelope to yield its density {approx}3 g cm{sup -3}.

  11. The trends high-contrast imaging survey. IV. The occurrence rate of giant planets around M dwarfs

    SciTech Connect

    Montet, Benjamin T.; Crepp, Justin R.; Johnson, John Asher; Howard, Andrew W.; Marcy, Geoffrey W.

    2014-01-20

    Doppler-based planet surveys have discovered numerous giant planets but are incomplete beyond several AU. At larger star-planet separations, direct planet detection through high-contrast imaging has proven successful, but this technique is sensitive only to young planets and characterization relies upon theoretical evolution models. Here we demonstrate that radial velocity measurements and high-contrast imaging can be combined to overcome these issues. The presence of widely separated companions can be deduced by identifying an acceleration (long-term trend) in the radial velocity of a star. By obtaining high spatial resolution follow-up imaging observations, we rule out scenarios in which such accelerations are caused by stellar binary companions with high statistical confidence. We report results from an analysis of Doppler measurements of a sample of 111 M-dwarf stars with a median of 29 radial velocity observations over a median time baseline of 11.8 yr. By targeting stars that exhibit a radial velocity acceleration ({sup t}rend{sup )} with adaptive optics imaging, we determine that 6.5% ± 3.0% of M-dwarf stars host one or more massive companions with 1 < m/M{sub J} < 13 and 0 < a < 20 AU. These results are lower than analyses of the planet occurrence rate around higher-mass stars. We find the giant planet occurrence rate is described by a double power law in stellar mass M and metallicity F ≡ [Fe/H] such that f(M,F)=0.039{sub −0.028}{sup +0.056}M{sup 0.8{sub −}{sub 0}{sub .}{sub 9}{sup +{sup 1{sup .{sup 1}}}}}10{sup (3.8±1.2)F}. Our results are consistent with gravitational microlensing measurements of the planet occurrence rate; this study represents the first model-independent comparison with microlensing observations.

  12. How the presence of a gas giant affects the formation of mean-motion resonances between two low-mass planets in a locally isothermal gaseous disc

    NASA Astrophysics Data System (ADS)

    Podlewska-Gaca, E.; Szuszkiewicz, E.

    2014-03-01

    In this paper we investigate the possibility of a migration-induced resonance locking in systems containing three planets, namely an Earth analogue (1 M⊕), a super-Earth (4 M⊕) and a gas giant (one Jupiter mass). The planets have been listed in order of increasing orbital periods. All three bodies are embedded in a locally isothermal gaseous disc and orbit around a solar mass star. We are interested in answering the following questions: will the low-mass planets form the same resonant structures with each other in the vicinity of the gas giant as in the case when the gas giant is absent? More in general, how will the presence of the gas giant affect the evolution of the two low-mass planets? When there is no gas giant in the system, it has been already shown that if the two low-mass planets undergo a convergent differential migration, they will capture each other in a mean-motion resonance. For the choices of disc parameters and planet masses made in this paper, the formation of the 5:4 resonance in the absence of the Jupiter has been observed in a previous investigation and confirmed here. In this work we add a gas giant on the most external orbit of the system in such a way that its differential migration is convergent with the low-mass planets. We show that the result of this set-up is the speeding up of the migration of the super-Earth and, after that, all three planets become locked in a triple mean-motion resonance. However, this resonance is not maintained due to the low-mass planet eccentricity excitation, a fact that leads to close encounters between planets and eventually to the ejection from the internal orbits of one or both low-mass planets. We have observed that the ejected low-mass planets can leave the system, fall into a star or become the external planet relative to the gas giant. In our simulations the latter situation has been observed for the super-Earth. It follows from the results presented here that the presence of a Jupiter-like planet

  13. Close-in planets around giant stars. Lack of hot-Jupiters and prevalence of multiplanetary systems

    NASA Astrophysics Data System (ADS)

    Lillo-Box, J.; Barrado, D.; Correia, A. C. M.

    2016-05-01

    Extrasolar planets abound in almost any possible configuration. However, until five years ago, there was a lack of planets orbiting closer than 0.5 au to giant or subgiant stars. Since then, recent detections have started to populated this regime by confirming 13 planetary systems. We discuss the properties of these systems in terms of their formation and evolution off the main sequence. Interestingly, we find that 70.0 ± 6.6% of the planets in this regime are inner components of multiplanetary systems. This value is 4.2σ higher than for main-sequence hosts, which we find to be 42.4 ± 0.1%. The properties of the known planets seem to indicate that the closest-in planets (a< 0.06 au) to main-sequence stars are massive (i.e., hot Jupiters) and isolated and that they are subsequently engulfed by their host as it evolves to the red giant branch, leaving only the predominant population of multiplanetary systems in orbits 0.06

  14. Shedding Light on the Eccentricity Valley: Gap Heating and Eccentricity Excitation of Giant Planets in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Tsang, David; Turner, Neal J.; Cumming, Andrew

    2015-01-01

    We show that the first order (non-co-orbital) corotation torques are significantly modified by entropy gradients in a non-barotropic protoplanetary disk. Such non-barotropic torques can dramatically alter the balance that, for barotropic cases, results in the net eccentricity damping for giant gap-clearing planets embedded in the disk. We demonstrate that stellar illumination can heat the gap enough for the planet's orbital eccentricity to instead be excited. We also discuss the "Eccentricity Valley" noted in the known exoplanet population, where low-metallicity stars have a deficit of eccentric planets between ~0.1 and ~1 AU compared to metal-rich systems. We show that this feature in the planet distribution may be due to the self-shadowing of the disk by a rim located at the dust sublimation radius ~0.1 AU, which is known to exist for several T Tauri systems. In the shadowed region between ~0.1 and ~1 AU, lack of gap insolation allows disk interactions to damp eccentricity. Outside such shadowed regions stellar illumination can heat the planetary gaps and drive eccentricity growth for giant planets. We suggest that the self-shadowing does not arise at higher metallicity due to the increased optical depth of the gas interior to the dust sublimation radius.

  15. Shedding light on the eccentricity valley: Gap heating and eccentricity excitation of giant planets in protoplanetary disks

    SciTech Connect

    Tsang, David; Cumming, Andrew; Turner, Neal J.

    2014-02-20

    We show that the first order (non-co-orbital) corotation torques are significantly modified by entropy gradients in a non-barotropic protoplanetary disk. Such non-barotropic torques can dramatically alter the balance that, for barotropic cases, results in the net eccentricity damping for giant gap-clearing planets embedded in the disk. We demonstrate that stellar illumination can heat the gap enough for the planet's orbital eccentricity to instead be excited. We also discuss the 'Eccentricity Valley' noted in the known exoplanet population, where low-metallicity stars have a deficit of eccentric planets between ∼0.1 and ∼1 AU compared to metal-rich systems. We show that this feature in the planet distribution may be due to the self-shadowing of the disk by a rim located at the dust sublimation radius ∼0.1 AU, which is known to exist for several T Tauri systems. In the shadowed region between ∼0.1 and ∼1 AU, lack of gap insolation allows disk interactions to damp eccentricity. Outside such shadowed regions stellar illumination can heat the planetary gaps and drive eccentricity growth for giant planets. We suggest that the self-shadowing does not arise at higher metallicity due to the increased optical depth of the gas interior to the dust sublimation radius.

  16. Effects of latent heating on driving atmospheric circulation of brown dwarfs and directly imaged giant planets

    NASA Astrophysics Data System (ADS)

    Tan, Xianyu; Showman, Adam P.

    2015-12-01

    Growing observations of brown dwarfs (BDs) and directly imaged extrasolar giant planets (EGPs), such as brightness variability and surface maps have provided evidence for strong atmospheric circulation on these worlds. Previous studies that serve to understand the atmospheric circulation of BDs include modeling of convection from the interior and its interactions with stably stratified atmospheres. These models show that such interactions can drive an atmospheric circulation, forming zonal jets and/or vortices. However, these models are dry, not including condensation of various chemical species. Latent heating from condensation of water has previously been shown to play an important role on driving the zonal jets on four giant planets in our solar system. As such, condensation cycles of various chemical species are believed to be an important source in driving the atmospheric circulation of BDs and directly imaged EGPs. Here we present results from three-dimensional simulations for the atmospheres of BDs and EGPs based on a general circulation model that includes the effect of a condensate cycle. Large-scale latent heating and molecular weight effect due to condensation of a single species are treated explicitly. We examine the circulation patterns caused by large-scale latent heating which results from condensation of silicate vapor in hot dwarfs and water vapor in the cold dwarfs. By varying the abundance of condensable vapor and the radiative timescale, we conclude that under normal atmospheric conditions of BDs (hot and thus with relatively short radiative timescale), latent heating alone by silicate vapor is unable to drive a global circulation, leaving a quiescent atmosphere, because of the suppression to moist instability by downward transport of dry air. Models with relatively long radiative timescale, which may be the case for cooler bodies, tend to maintain an active hydrological cycle and develop zonal jets. Once condensation happens, storms driven by

  17. Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations

    NASA Astrophysics Data System (ADS)

    Nielsen, Eric L.; Close, Laird M.; Biller, Beth A.; Masciadri, Elena; Lenzen, Rainer

    2008-02-01

    We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast curves from 22 of the stars observed with the VLT NACO adaptive optics system by Masciadri and coworkers and 48 of the stars observed with the VLT NACO SDI and MMT SDI devices by Biller and coworkers (for a total of 60 unique stars), we consider what distributions of planet masses and semimajor axes can be ruled out by these data, based on Monte Carlo simulations of planet populations. We can set the following upper limit with 95% confidence: the fraction of stars with planets with semimajor axis between 20 and 100 AU, and mass above 4 MJup, is 20% or less. Also, with a distribution of planet mass of dN/dM propto M-1.16 in the range of 0.5-13 MJup, we can rule out a power-law distribution for semimajor axis (dN/da propto aα) with index 0 and upper cutoff of 18 AU, and index -0.5 with an upper cutoff of 48 AU. For the distribution suggested by Cumming et al., a power-law of index -0.61, we can place an upper limit of 75 AU on the semimajor axis distribution. In general, we find that even null results from direct imaging surveys are very powerful in constraining the distributions of giant planets (0.5-13 MJup) at large separations, but more work needs to be done to close the gap between planets that can be detected by direct imaging, and those to which the radial velocity method is sensitive.

  18. Extrasolar planets and brown dwarfs around A-F type stars. VIII. A giant planet orbiting the young star HD 113337

    NASA Astrophysics Data System (ADS)

    Borgniet, S.; Boisse, I.; Lagrange, A.-M.; Bouchy, F.; Arnold, L.; Díaz, R. F.; Galland, F.; Delorme, P.; Hébrard, G.; Santerne, A.; Ehrenreich, D.; Ségransan, D.; Bonfils, X.; Delfosse, X.; Santos, N. C.; Forveille, T.; Moutou, C.; Udry, S.; Eggenberger, A.; Pepe, F.; Astudillo, N.; Montagnier, G.

    2014-01-01

    Aims: In the context of the search for extrasolar planets and brown dwarfs around early-type main-sequence stars we present the detection of a giant planet around the young F-type star HD 113337. We estimated the age of the system to be 150-50+100 Myr. Interestingly, an infrared excess attributed to a cold debris disk was previously detected around this star. Methods: We used the SOPHIE spectrograph on the 1.93 m telescope at Observatoire de Haute-Provence to obtain ~300 spectra over six years. We used our tool dedicated to the spectra analysis of A and F stars to derive the radial velocity variations. Results: The data reveal a period of 324.0+1.7-3.3 days that we attribute to a giant planet with a minimum mass of 2.83 ± 0.24 MJup in an eccentric orbit with e = 0.46 ± 0.04. A long-term quadratic drift, which we assign to be probably of stellar origin, is superimposed on the Keplerian solution. Based on observations made with the SOPHIE spectrograph at the Observatoire de Haute-Provence (CNRS, France).Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A65

  19. Planetary Growth: From the Gap-opening Mass to the Final Mass of the Giant Planet

    NASA Astrophysics Data System (ADS)

    Estrada, P. R.; Mosqueira, I.

    2003-08-01

    Protoplanets migrate inwards due to the tidal interaction with the nebula disk (Goldreich and Tremaine 1980; Ward 1986). In a minimum mass solar nebula an inwardly migrating protoplanet may open a gap and stall when it reaches a mass between 2-15 MEarth provided α < 10-4 (Rafikov 2002), thus improving its chances of survival. Yet the migration time of a protoplanet in a minimum mass solar nebula may be significantly faster than the formation time of a sufficiently large planetary core ( ˜ 10 MEarth) to allow gas accretion. However, recent analytical work (Tanaka et al. 2002) and numerical simulations (D'Angelo et al. 2002; Bate et al. 2003) have increased the timescale of migration by up to an order of magnitude (depending on disk conditions and whether the corotation resonance saturates or not) compared to previous estimates (Ward 1997). Furthermore, increasing the gas surface density with respect to the minimum mass solar nebula may shorten the formation time of a planetary core (Tanaka and Ida 1999). Provided that a planetary core formed at Jupiter's location in time to open a gap, and that the nebula was weakly turbulent at the time of its formation, gap-opening might have left Jupiter in its present orbit far from the Sun. The issue then arises as to what determines the final mass of the planet. Here we consider the possibility that Jupiter accreted its mass from an annulus of gas within the shocking distance of acoustic waves (Goodman and Rafikov 2001) launched by the growing protoplanet, estimate the gas surface density based on this assumption, and compute the gap-opening critical mass in such a disk. A similar argument applied to the outer giant planets would require lower gas surface densities outside Jupiter, which may be incompatible with a strongly turbulent disk. However, this argument is complicated by the effective viscosity due to the planetary tidal torques themselves. A possible role for the thermal condition will be discussed.

  20. The Formation of Cores of Giant Planets at Convergence Zones of Planetary Migration

    NASA Astrophysics Data System (ADS)

    Sirono, Sin-iti; Katayama, Masahumi

    2016-10-01

    The formation of solid cores in giant planets of mass ∼ 10 {M}\\oplus is numerically simulated following the scenario of Sándor et al. In this scenario, there are two convergence zones, corresponding to the outer and inner edges of the dead zone, where the torque exerted on planetary embryos by the gas nebula is zero. At the outer edge of the dead zone, anticyclonic vortices accumulate infalling dust aggregates, and planetary embryos are continuously formed in this scenario. We performed N-body simulations and show that massive objects of ≃ 10 {M}\\oplus are formed in ∼2.5 Myr, starting from the embryos. The largest object is formed at the inner convergence zone, although planetary embryos are placed at the outer convergence zone. This is due to the scattering of embryos from the outer to the inner convergence zone, and the shorter damping timescale of eccentricity at the inner convergence zone compared to the outer one. We varied the migration timescale due to the torque from gas by changing the gas surface density around the convergence zones. We found that there is a critical migration timescale below which 10 {M}\\oplus -sized objects are formed. Furthermore, we conducted simulations in which the gas surface density evolves according to viscous accretion. The largest object is also formed at the inner convergence zone irrespective of the strength of turbulence. Throughout the simulations, the location of the largest mass is the inner convergence zone. We confirmed that the formation timescale of a core of a Jovian planet can be explained in this scenario.

  1. The great dichotomy of the Solar System: Small terrestrial embryos and massive giant planet cores

    NASA Astrophysics Data System (ADS)

    Morbidelli, A.; Lambrechts, M.; Jacobson, S.; Bitsch, B.

    2015-09-01

    The basic structure of the Solar System is set by the presence of low-mass terrestrial planets in its inner part and giant planets in its outer part. This is the result of the formation of a system of multiple embryos with approximately the mass of Mars in the inner disk and of a few multi-Earth-mass cores in the outer disk, within the lifetime of the gaseous component of the protoplanetary disk. What was the origin of this dichotomy in the mass distribution of embryos/cores? We show in this paper that the classic processes of runaway and oligarchic growth from a disk of planetesimals cannot explain this dichotomy, even if the original surface density of solids increased at the snowline. Instead, the accretion of drifting pebbles by embryos and cores can explain the dichotomy, provided that some assumptions hold true. We propose that the mass-flow of pebbles is two-times lower and the characteristic size of the pebbles is approximately ten times smaller within the snowline than beyond the snowline (respectively at heliocentric distance r rice , where rice is the snowline heliocentric distance), due to ice sublimation and the splitting of icy pebbles into a collection of chondrule-size silicate grains. In this case, objects of original sub-lunar mass would grow at drastically different rates in the two regions of the disk. Within the snowline these bodies would reach approximately the mass of Mars while beyond the snowline they would grow to ∼ 20 Earth masses. The results may change quantitatively with changes to the assumed parameters, but the establishment of a clear dichotomy in the mass distribution of protoplanets appears robust provided that there is enough turbulence in the disk to prevent the sedimentation of the silicate grains into a very thin layer.

  2. Large eccentricity, low mutual inclination: the three-dimensional architecture of a hierarchical system of giant planets

    SciTech Connect

    Dawson, Rebekah I.; Clubb, Kelsey I.; Johnson, John Asher; Murray-Clay, Ruth A.; Fabrycky, Daniel C.; Foreman-Mackey, Daniel; Buchhave, Lars A.; Cargile, Phillip A.; Fulton, Benjamin J.; Howard, Andrew W.; Hebb, Leslie; Huber, Daniel; Shporer, Avi; Valenti, Jeff A.

    2014-08-20

    We establish the three-dimensional architecture of the Kepler-419 (previously KOI-1474) system to be eccentric yet with a low mutual inclination. Kepler-419b is a warm Jupiter at semi-major axis a=0.370{sub −0.006}{sup +0.007} AU with a large eccentricity (e = 0.85{sub −0.07}{sup +0.08}) measured via the 'photoeccentric effect'. It exhibits transit timing variations (TTVs) induced by the non-transiting Kepler-419c, which we uniquely constrain to be a moderately eccentric (e = 0.184 ± 0.002), hierarchically separated (a = 1.68 ± 0.03 AU) giant planet (7.3 ± 0.4 M {sub Jup}). We combine 16 quarters of Kepler photometry, radial-velocity (RV) measurements from the HIgh Resolution Echelle Spectrometer on Keck, and improved stellar parameters that we derive from spectroscopy and asteroseismology. From the RVs, we measure the mass of the inner planet to be 2.5 ± 0.3 M {sub Jup} and confirm its photometrically measured eccentricity, refining the value to e = 0.83 ± 0.01. The RV acceleration is consistent with the properties of the outer planet derived from TTVs. We find that despite their sizable eccentricities, the planets are coplanar to within 9{sub −6}{sup +8} degrees, and therefore the inner planet's large eccentricity and close-in orbit are unlikely to be the result of Kozai migration. Moreover, even over many secular cycles, the inner planet's periapse is most likely never small enough for tidal circularization. Finally, we present and measure a transit time and impact parameter from four simultaneous ground-based light curves from 1 m class telescopes, demonstrating the feasibility of ground-based follow-up of Kepler giant planets exhibiting large TTVs.

  3. A UNIFORM ANALYSIS OF 118 STARS WITH HIGH-CONTRAST IMAGING: LONG-PERIOD EXTRASOLAR GIANT PLANETS ARE RARE AROUND SUN-LIKE STARS

    SciTech Connect

    Nielsen, Eric L.; Close, Laird M.

    2010-07-10

    We expand on the results of Nielsen et al., using the null result for giant extrasolar planets around the 118 target stars from the Very Large Telescope (VLT) NACO H- and Ks-band planet search (conducted by Masciadri and collaborators in 2003 and 2004), the VLT and MMT Simultaneous Differential Imager survey, and the Gemini Deep Planet Survey to set constraints on the population of giant extrasolar planets. Our analysis is extended to include the planet luminosity models of Fortney et al., as well as the correlation between stellar mass and frequency of giant planets found by Johnson et al. Doubling the sample size of FGKM stars strengthens our conclusions: a model for extrasolar giant planets with power laws for mass and semimajor axis as given by Cumming et al. cannot, with 95% confidence, have planets beyond 65 AU, compared to the value of 94 AU reported by Nielsen et al., using the models of Baraffe et al. When the Johnson et al. correction for stellar mass (which gives fewer Jupiter-mass companions to M stars with respect to solar-type stars) is applied, however, this limit moves out to 82 AU. For the relatively new Fortney et al. models, which predict fainter planets across most of parameter space, these upper limits, with and without a correction for stellar mass, are 182 and 234 AU, respectively.

  4. Characterizing Cold Giant Planets in Reflected Light: Lessons from 50 Years of Outer Solar System Exploration and Observation

    NASA Technical Reports Server (NTRS)

    Marley, Mark Scott; Hammel, Heidi

    2014-01-01

    A space based coronagraph, whether as part of the WFIRST/AFTA mission or on a dedicated space telescope such as Exo-C or -S, will be able to obtain photometry and spectra of multiple gas giant planets around nearby stars, including many known from radial velocity detections. Such observations will constrain the masses, atmospheric compositions, clouds, and photochemistry of these worlds. Giant planet albedo models, such as those of Cahoy et al. (2010) and Lewis et al. (this meeting), will be crucial for mission planning and interpreting the data. However it is equally important that insights gleaned from decades of solar system imaging and spectroscopy of giant planets be leveraged to optimize both instrument design and data interpretation. To illustrate these points we will draw on examples from solar system observations, by both HST and ground based telescopes, as well as by Voyager, Galileo, and Cassini, to demonstrate the importance clouds, photochemical hazes, and various molecular absorbers play in sculpting the light scattered by solar system giant planets. We will demonstrate how measurements of the relative depths of multiple methane absorption bands of varying strengths have been key to disentangling the competing effects of gas column abundances, variations in cloud height and opacity, and scattering by high altitude photochemical hazes. We will highlight both the successes, such as the accurate remote determination of the atmospheric methane abundance of Jupiter, and a few failures from these types of observations. These lessons provide insights into technical issues facing spacecraft designers, from the selection of the most valuable camera filters to carry to the required capabilities of the flight spectrometer, as well as mission design questions such as choosing the most favorable phase angles for atmospheric characterization.

  5. Gas Accretion by Giant Planets: 3D Simulations of Gap Opening and Dynamics of the Circumplanetary Disk

    NASA Astrophysics Data System (ADS)

    Morbidelli, Alessandro; Szulagyi, J.; Crida, A.; Tanigawa, T.; Lega, E.; Masset, F.; Bitsch, B.

    2013-10-01

    What sets the terminal mass of a giant planet once the latter enters into a runaway gas-accretion phase? The formation of a gap around the planet's orbit may be an answer, provided that the gap is wide and deep enough. A wide-spread idea is that this happens if the viscosity in the circumstellar disk is small, i.e. if planets form in the "dead zone". With 3D hydrodynamical simulations we study the formation of a gap in details. We find an interesting 4-step meridional loop in the gas dynamics: (1) the gas flows into the gap at the top layer of the disk; (2) then it falls towards the disk's midplane; (3) the planet keeps the gap open by pushing this infalling gas back into the disk; (4) the gas rises back to the disk's surface, which closes the loop. The gas flow in this loop is governed by the viscous timescale at the surface of the disk. It is generally accepted that the surface layer of the disk is MRI-active and viscous, even if a dead zone is present near the midplane. Thus, there should always be enough gas flowing into the gap for a Jupiter-mass planet to accrete at a fast rate, in absence of other regulation mechanisms. However, only a very small portion of the gas flowing into the gap is directly accreted by the planet. Most of the gas falling towards the planet forms a circumplanetary disk (CPD), due to angular momentum conservation. If the CPD is MRI-inactive, as suggested by Turner et al. (2010) and Fujii et al. (2011), it can act as a bottle-neck for planet accretion. We find that the main mechanism that allows the CPD to lose angular momentum is the torque exerted by the star via a spiral density wave. We compute that this promotes the accretion of 0.025% of the mass of the CPD per year, for a Jupiter mass planet at 5.2 AU, independent of viscosity. By balancing the pressure of the vertical inflow with that internal to the CPD, we estimate that the CPD should contain less than 1% of the planet's mass. This leads to a mass-doubling timescale for Jupiter

  6. The first known Uranian Trojan and the frequency of temporary giant-planet co-orbitals

    NASA Astrophysics Data System (ADS)

    Greenstreet, Sarah; Alexandersen, M.; Gladman, B.; Kavelaars, J.; Petit, J.; Gwyn, S.

    2013-10-01

    We report the first discovery of a Uranian Trojan (2011 QF99) in 2011-2012 CFHT Megacam imaging taken for a 20 square degree outer Solar System survey designed to detect and track Trans-Neptunian Objects and Centaurs. The orbit of the newly discovered object was constrained with 29 astrometric measurements over 7 dark runs with a total arc of 419 days. Numerical integrations of both the nominal orbit and all other orbits within the (already small) orbital uncertainties show 2011 QF99 oscillates around the L4 Lagrange point 60 degrees ahead of Uranus for >70 kyr and remains co-orbital (in 1:1 resonance) for ~1 Myr before becoming a Centaur. We performed additional orbital integrations to investigate the possibility the object could have evolved to its current orbit from a nearby, stable niche of phase-space. However, test particles started on orbits in the small region of phase-space surrounding the nominal orbit remained co-orbital for <100 Myr, most for <10 Myr. This leads to the conclusion that 2011 QF99 must be a temporary co-orbital instead of being a primordial Trojan. To investigate the frequency and duration (to factor of two accuracy) of temporary co-orbital captures with Uranus and Neptune, we construct a model of Centaurs supplied from the transneptunian region over 1 Gyr, building a relative orbital distribution for the a<34 AU region. The simulation output interval of 300 yr for the planets and all a<34 AU particles allows the 1:1 resonant argument to be well sampled; to our knowledge, this is the first time such a meticulous search for short-term co-orbitals of giant planets has been performed for an armada of incoming scattering objects. Analysis of the particle histories showed that at any given time, significant fractions (0.4% and 2.8%) of the a<34 AU Centaur population will be Uranian and Neptunian co-orbitals, respectively. We show for the first time that the high fraction 3%) of the transient co-orbital Centaurs in the IAU Minor Planet Center

  7. NH3, H2S, and the Radio Brightness Temperature Spectra of the Giant Planets

    NASA Technical Reports Server (NTRS)

    Spilker, Thomas R.

    1995-01-01

    Recent radio interferometer observations of Neptune enable comparisons of the radio brightness temperature (T(sub B)) spectra of all four giant planets. This comparison reveals evidence for fundamental differences in the compositions of Uranus' and Neptune's upper tropospheres, particularly in their ammonia (NH3) and hydrogen sulfide (H2S) mixing ratios, despite those planets' outward similarities. The tropospheric abundances of these constituents yield information about their deep abundances, and ultimately about the formation of the planets from the presolar nebula (Atreya et al.). Figures 1, 2, 3, and 4 show the T(sub B) spectra of Jupiter, Saturn, Uranus, and Neptune, respectively, from 0.1 to tens of cm wavelength. The data shown are collected from many observers. Data for Jupiter, Saturn, and Uranus are those cataloged by de Pater and Massie (1985), plus the Saturn Very Large Array (VLA) data by Grossman et al. Figure 3, Uranus, shows only data acquired since 1973. Before 1973 Uranus' T(sub B) increased steadily as its pole moved into view, causing significant scatter in those data. Neptune data at greater than 1 cm, all taken at the VLA, are collected from de Pater and Richmond, de Pater et al., and Hofstadter. For a variety of reasons, such as susceptibility to source confusion, single-dish data at those wavelengths are much noisier than the more reliable VLA data and have been ignored. Single-dish data by Griffin and Orton shortward of 0.4 cm are shown, along with the Owens Valley Radio Observatory (interferometer) datum at 0.266 cm by Muhleman and Berge. Spectra of Jupiter, Saturn, and Neptune share certain gross characteristics. In each spectrum, T(sub B) at 1.3 cm is approximately 120-140 K, less than approximately 30 K different from that at 0.1 cm. All three spectra show a break in slope at or near 1.3 cm, with T(sub B) increasing fairly rapidly with wavelength longward of 1.3 cm. Visible and IR spectroscopy show that NH3, whose strong inversion

  8. GASEOUS MEAN OPACITIES FOR GIANT PLANET AND ULTRACOOL DWARF ATMOSPHERES OVER A RANGE OF METALLICITIES AND TEMPERATURES

    SciTech Connect

    Freedman, Richard S.; Lustig-Yaeger, Jacob; Fortney, Jonathan J.; Lupu, Roxana E.; Marley, Mark S.; Lodders, Katharina

    2014-10-01

    We present new calculations of Rosseland and Planck gaseous mean opacities relevant to the atmospheres of giant planets and ultracool dwarfs. Such calculations are used in modeling the atmospheres, interiors, formation, and evolution of these objects. Our calculations are an expansion of those presented in Freedman et al. to include lower pressures, finer temperature resolution, and also the higher metallicities most relevant for giant planet atmospheres. Calculations span 1 μbar to 300 bar, and 75-4000 K, in a nearly square grid. Opacities at metallicities from solar to 50 times solar abundances are calculated. We also provide an analytic fit to the Rosseland mean opacities over the grid in pressure, temperature, and metallicity. In addition to computing mean opacities at these local temperatures, we also calculate them with weighting functions up to 7000 K, to simulate the mean opacities for incident stellar intensities, rather than locally thermally emitted intensities. The chemical equilibrium calculations account for the settling of condensates in a gravitational field and are applicable to cloud-free giant planet and ultracool dwarf atmospheres, but not circumstellar disks. We provide our extensive opacity tables for public use.

  9. JUPITER WILL BECOME A HOT JUPITER: CONSEQUENCES OF POST-MAIN-SEQUENCE STELLAR EVOLUTION ON GAS GIANT PLANETS

    SciTech Connect

    Spiegel, David S.; Madhusudhan, Nikku E-mail: Nikku.Madhusudhan@yale.edu

    2012-09-10

    When the Sun ascends the red giant branch (RGB), its luminosity will increase and all the planets will receive much greater irradiation than they do now. Jupiter, in particular, might end up more highly irradiated than the hot Neptune GJ 436b and, hence, could appropriately be termed a 'hot Jupiter'. When their stars go through the RGB or asymptotic giant branch stages, many of the currently known Jupiter-mass planets in several-AU orbits will receive levels of irradiation comparable to the hot Jupiters, which will transiently increase their atmospheric temperatures to {approx}1000 K or more. Furthermore, massive planets around post-main-sequence stars could accrete a non-negligible amount of material from the enhanced stellar winds, thereby significantly altering their atmospheric chemistry as well as causing a significant accretion luminosity during the epochs of most intense stellar mass loss. Future generations of infrared observatories might be able to probe the thermal and chemical structure of such hot Jupiters' atmospheres. Finally, we argue that, unlike their main-sequence analogs (whose zonal winds are thought to be organized in only a few broad, planetary-scale jets), red-giant hot Jupiters should have multiple, narrow jets of zonal winds and efficient day-night redistribution.

  10. Searching for extra-solar planets and probing the atmosphere of Bulge giant stars through gravitational microlensing

    NASA Astrophysics Data System (ADS)

    Cassan, Arnaud

    2005-12-01

    A galactic microlensing effect occurs when a luminous object (the source) located in the Bulge of the Milky Way is temporarily magnified by an intervening star (the "microlens'') passing close to its line of sight. This phenomenom is used for searching extra-solar planets and constraining their abundance, as well as probing the atmosphere of Bulge giant stars. The PLANET collaboration (Probing Lensing Anomalies NETwork) monitors carefully chosen ongoing microlensing events on a round-the-clock basis from observatories in the southern hemisphere. Mathematical and numerical methods are developed to deal with both the highly non-linear equations and the wide parameter space plagued with many local minima. Microlensing exoplanet detection is possible because planets can induce perturbations to the standard lensing light curves. Its sensitivity can go down to Earth-mass planets, thanks to gravitational caustics that arise from a binary lens. If crossed by the source, additional secondary magnification peaks in the light curve can occur. OGLE 2005-BLG-390Lb is the third extra-solar planet detected by this method so far, and its discovery is reported here. It is the lightest exoplanet to date - about five Earth masses - located at a rather large distance of its star, that is about three astronomical units. A selection of microlensing events monitored during the 1995-2004 period was used to derive limits on exoplanets abundance around red dwarf stars. The method is described and detection efficiency diagrams are provided as a basis of the statistical analysis. Last, a differential magnification effect over the disk of the source star is used as a tool to probe Bulge giants stellar atmospheres. Limb-darkening parameters of a set of stars have been measured and compared to atmosphere models. Moreover, a high-resolution spectroscopic monitoring of a Bulge G5III giant at 9 kpc made possible both the measurement of the individual lines equivalent width and the direct detection

  11. Ab Initio Simulations of Water in the Interiors of Ice Giant Planets

    NASA Astrophysics Data System (ADS)

    Militzer, B.; Zhang, S.

    2014-12-01

    Water is one of the most prevalent substances in our solar system. Large quantities are assumed to be stored in the interiors of ice giant planets. Water has an unusually rich phase diagram with 15 solid phases that were determined experimentally and 5 additional ones that were predicted theoretically. At megabar pressures and elevated temperatures, water is predicted to assume a superionic state where the oxygen ions remain confined to lattice sites while the hydrogen ions move through the crystal like a fluid. In our recent article [Physical Review Letters 110 (2013) 151102], we predicted the oxygen sub-lattice to assume a face-centered cubic structure at pressures above 1 Mbar. In this presentation, we present results from additional density functional molecular dynamics simulations and predict the existence of new, not close packed phase. We employed a thermodynamics integration technique to derive the entropy and the Gibbs free energy. We discuss how a novel superionic state could be identified in high pressure experiments and talk about the implications for the interiors of Uranus and Neptune.

  12. Gas phase synthesis of organophosphorus compounds and the atmosphere of the giant planets

    NASA Astrophysics Data System (ADS)

    Bossard, A. R.; Kamga, R.; Raulin, F.

    1986-08-01

    Spark discharge and UV irradiation experiments were performed to investigate the interactions of CH4 and PH3 and the chemical evolution of PH3-H2O-NH3-CH4 mixtures in the upper atmospheres of the giant planets. The spark discharges were performed with various combinations of CH4-PH3, CH-PH3-H2, C2H6-PH3, and CH3PH2-CH4. PH3 alone and CH4-PH3 were exposed to 147 nm UV light. Sparks released into the hydrocarbon-phosphine mixtures induced the formation of alkylphosphines. The main products were H2, C2H6 and CH3PH2 when the initial mole fraction of PH3 was low. If the fraction of PH3 was high, the main products were He, CH3PH2 and P2H4. A gas phase chemical reaction model was defined for the formation reaction of methylphosphine. UV irradiation of CH4-PH3 usually produced a solid deposit and the constituents H2 and P2H4. The stability of the various reaction products in the Saturn and Jupiter atmospheres is discussed.

  13. Ab initio simulations for matter deep in the interior of giant planets: equation of state data and transport coefficients

    NASA Astrophysics Data System (ADS)

    Redmer, Ronald; Becker, Andreas; Bethkenhagen, Mandy; French, Martin; Lorenzen, Winfried

    2014-05-01

    The behavior of warm dense matter (pressures of several Mbar and temperatures of several eV) is of paramount importance for interior and dynamo models of giant planets. However, the high-pressure phase diagram of even the simplest and most abundant elements hydrogen and helium as well as that of molecular systems (e.g. water, ammonia, methane and their mixtures) is not well known. The complexity of the behavior arises from metal-insulator transitions and demixing phenomena that occur at high pressures. New phases with exotic properties (e.g. superionic phases with proton conduction) have been predicted as well. These effects will have a strong impact on interior and dynamo models of solar and extrasolar giant planets. We apply ab initio molecular dynamics simulations based on finite-temperature density functional theory to calculate the equation of state data, the high-pressure phase diagram, and the transport properties (electrical and thermal conductivity, viscosity) for a wide range of densities and temperatures. We present new results for hydrogen-helium mixtures and for water, ammonia, and methane. We discuss implications for the interior and magnetic field structure of the gas giants Jupiter and Saturn and the ice giants Uranus and Neptune.

  14. KEPLER-63b: A GIANT PLANET IN A POLAR ORBIT AROUND A YOUNG SUN-LIKE STAR

    SciTech Connect

    Sanchis-Ojeda, Roberto; Winn, Joshua N.; Albrecht, Simon; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.; Johnson, John Asher; Torres, Guillermo; Carter, Joshua A.; Dawson, Rebekah I.; Geary, John C.; Campante, Tiago L.; Chaplin, William J.; Davies, Guy R.; Lund, Mikkel N.; Buchhave, Lars A.; Everett, Mark E.; Fischer, Debra A.; Gilliland, Ronald L.; Horch, Elliott P.; and others

    2013-09-20

    We present the discovery and characterization of a giant planet orbiting the young Sun-like star Kepler-63 (KOI-63, m{sub Kp} = 11.6, T{sub eff} = 5576 K, M{sub *} = 0.98 M{sub ☉}). The planet transits every 9.43 days, with apparent depth variations and brightening anomalies caused by large starspots. The planet's radius is 6.1 ± 0.2 R{sub ⊕}, based on the transit light curve and the estimated stellar parameters. The planet's mass could not be measured with the existing radial-velocity data, due to the high level of stellar activity, but if we assume a circular orbit, then we can place a rough upper bound of 120 M{sub ⊕} (3σ). The host star has a high obliquity (ψ = 104°), based on the Rossiter-McLaughlin effect and an analysis of starspot-crossing events. This result is valuable because almost all previous obliquity measurements are for stars with more massive planets and shorter-period orbits. In addition, the polar orbit of the planet combined with an analysis of spot-crossing events reveals a large and persistent polar starspot. Such spots have previously been inferred using Doppler tomography, and predicted in simulations of magnetic activity of young Sun-like stars.

  15. 1 to 2.4 microns spectrum and orbital properties of the Giant Planet Beta Pictoris b obtained with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Pueyo, Laurent; Chilcote, Jeffrey; Millar-Blanchaer, Max; Barman, Travis; Fitzgerald, Michael P.; Graham, James R.; Larkin, James; Kalas, Paul G.; dawson, Rebekah; Wang, Jason; Perrin, Marshall; Moon, Dae-Sik; Macintosh, Bruce

    2015-12-01

    We present a low-resolution multi-band spectrum of the planetary companion to the nearby young star beta Pictoris using the Gemini Planet Imager (GPI). GPI is designed to image and provide low-resolution spectra of Jupiter sized, self-luminous planetary companions around young nearby stars. While H-bandis the primary workhorse for the GPI Exoplanet Survey, the instrument is capable of observing in the near infrared covering Y, J, H, and K bands. These observations of Beta Pic Pictoris b were taken covering multiple bands as part of GPI’s verification and commissioning phase in 2013 and 2014. Using atmospheric models along with the H-band data we recently reported an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). A similar exercise was also carried out by an independent team using the J band data, and did yield similar conclusions. These values agree well with ”hot-start” predictions from planetary evolution models for a gas giant with mass between 10 and 12 M Jup and age between 10 and 20 Myr. Here we revisit these conclusions in light of a joint analysis of these two datasets along with the longer wavelength GPI spectrum in K band, and present refined constraints on the atmospheric properties of this giant planet. In addition, we present an updated orbit for Beta Pictoris b based on astrometric measurements taken using commissioning and subsequent monitoring observations, spanning 14 months. The planet has a semi-major axis of 9.2 (+1.5 -0.4) AU, with an eccentricity e≤ 0.26. The position angle of the ascending node is Ω=31.75 deg±0.15, offset from both the outer main disk and the inner disk seen in the GPI image. We finally discuss these properties in the context of planet-disk dynamical interactions.

  16. AN INTERPRETATION OF THE ORBITAL PERIOD DIFFERENCE BETWEEN HOT JUPITERS AND GIANT PLANETS ON LONG-PERIOD ORBITS

    SciTech Connect

    Jin Liping

    2010-09-10

    It is believed that a hot Jupiter (giant planet with a short period less than 10 days) forms in the outer region of a protoplanetary disk, then migrates inward to an orbit with a short period around 3 days, and stops there by a final stopping mechanism. The prominent problem is why hot Jupiters migrate inward to short-period orbits, while other extrasolar giant planets and Jovian planets in our solar system exist on long-period orbits. Here we show that this difference in orbital periods is caused by two populations of protoplanetary disks. One population experiences gravitational instability during some periods of their lifetime (GI disks), while the other does not (No-GI disks). In GI disks, planets can quickly migrate inward to short-period orbits to become hot Jupiters. In No-GI disks, the migration is so slow that planets can exist on long-period orbits. Protoplanetary disks are classified into the two populations because of the differences in properties of molecular cloud cores, from which disks from. We specifically compare our theory with observations. Our theory is supported by observations of extrasolar planets. We analyze the current status of our solar system and find that our solar nebula belongs to the population with a low migration rate. This is consistent with the observation that Jupiter and Saturn are indeed on long-period orbits. Our results further suggest that, in the future observations, a hot Jupiter cannot be found around a star with mass below a critical mass (0.14-0.28 M {sub sun}).

  17. Formation of Large Regular Satellites of Giant Planets in an Extended Gaseous Nebula: Subnebula Model and Accretion of Satellites

    NASA Technical Reports Server (NTRS)

    Mosqueira, I.; Estrada, P. R.

    2000-01-01

    We model the subnebulae of Jupiter and Saturn wherein satellite accretion took place. We expect a giant planet subnebula to be composed of an optically thick (given gaseous opacity) inner region inside of the planet's centrifugal radius (located at r(sub c, sup J) = l5R(sub J) for Jupiter and r(sub c, sup S) = 22R(sub S) for Saturn), and an optically thin, extended outer disk out to a fraction of the planet's Roche lobe, which we choose to be R(sub roche)/5 (located at approximately 150R(sub J) near the inner irregular satellites for Jupiter, and approximately 200R(sub S) near Phoebe for Saturn). This places Titan and Ganymede in the inner disk, Callisto and Iapetus in the outer disk, and Hyperion in the transition region. The inner disk is the leftover of the gas accreted by the protoplanet. The outer disk results from the solar torque on nebula gas flowing into the protoplanet during the time of giant planet gap opening. For the sake of specificity, we use a cosmic mixture 'minimum mass' model to constrain the gas densities of the inner disks of Jupiter and Saturn (and also Uranus). For the total mass of the outer disk we use the simple scaling M(sub disk) = M(sub P)tau(sub gap)/tau(sub acc), where M(sub P) is the mass of the giant planet, tau(sub gap) is the gap opening timescale, and tau(sub acc) is the giant planet accretion time. This gives a total outer disk mass of approximately 100M(sub Callisto) for Jupiter and possibly approximately 200M(sub Iapetus) for Saturn (which contain enough condensables to form Callisto and Iapetus respectively). Our model has Ganymede at a subnebula temperature of approximately 250 K and Titan at approximately 100 K. The outer disks of Jupiter and Saturn have constant temperatures of 130 K and 90 K respectively.

  18. Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars

    NASA Astrophysics Data System (ADS)

    Adibekyan, V. Zh.; Benamati, L.; Santos, N. C.; Alves, S.; Lovis, C.; Udry, S.; Israelian, G.; Sousa, S. G.; Tsantaki, M.; Mortier, A.; Sozzetti, A.; De Medeiros, J. R.

    2015-06-01

    We performed a uniform and detailed abundance analysis of 12 refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn, and V) for a sample of 257 G- and K-type evolved stars from the CORALIE planet search programme. To date, only one of these stars is known to harbour a planetary companion. We aimed to characterize this large sample of evolved stars in terms of chemical abundances and kinematics, thus setting a solid base for further analysis of planetary properties around giant stars. This sample, being homogeneously analysed, can be used as a comparison sample for other planet-related studies, as well as for different type of studies related to stellar and Galaxy astrophysics. The abundances of the chemical elements were determined using an local thermodynamic equilibrium (LTE) abundance analysis relative to the Sun, with the spectral synthesis code MOOG and a grid of Kurucz ATLAS9 atmospheres. To separate the Galactic stellar populations, both a purely kinematical approach and a chemical method were applied. We confirm the overabundance of Na in giant stars compared to the field FGK dwarfs. This enhancement might have a stellar evolutionary character, but departures from LTE may also produce a similar enhancement. Our chemical separation of stellar populations also suggests a `gap' in metallicity between the thick-disc and high-α metal-rich stars, as previously observed in dwarfs sample from HARPS. The present sample, as most of the giant star samples, also suffers from the B - V colour cut-off, which excludes low-log g stars with high metallicities, and high-log g star with low [Fe/H]. For future studies of planet occurrence dependence on stellar metallicity around these evolved stars, we suggest to use a subsample of stars in a `cut-rectangle' in the log g-[Fe/H] diagram to overcome the aforementioned issue.

  19. Bayesian thermal evolution models for giant planets: Helium rain and double-diffusive convection in Jupiter

    NASA Astrophysics Data System (ADS)

    Mankovich, Christopher; Fortney, Jonathan J.; Nettelmann, Nadine; Moore, Kevin

    2016-10-01

    Hydrogen and helium unmix when sufficiently cool, and this bears on the thermal evolution of all cool giant planets at or below one Jupiter mass. Over the past few years, ab initio simulations have put us in the era of quantitative predictions for this H-He immiscibility at megabar pressures. We present models for the thermal evolution of Jupiter, including its evolving helium distribution following one such ab initio H-He phase diagram. After 4 Gyr of homogeneous evolution, differentiation establishes a helium gradient between 1 and 2 Mbar that dynamically stabilizes the fluid to overturning convection. The result is a region undergoing overstable double-diffusive convection (ODDC), whose relatively weak vertical heat transport maintains a superadiabatic temperature gradient. With a general parameterization for the ODDC efficiency, the models can reconcile Jupiter's intrinsic flux, atmospheric helium content, and mean radius at the age of the solar system if the H-He phase diagram is translated to cooler temperatures.We cast our nonadiabatic thermal evolution models in a Markov chain Monte Carlo parameter estimation framework, retrieving the total heavy element mass, the superadiabaticity of the deep temperature gradient, and the phase diagram temperature offset. Models using the interpolated Saumon, Chabrier and van Horn (1995) equation of state (SCvH-I) favor very inefficient ODDC such that the deep temperature gradient is strongly superadiabatic, forming a thermal boundary layer that allows the molecular envelope to cool quickly while the deeper interior (most of the planet's mass) actually heats up over time. If we modulate the overall cooling time with an additional free parameter, mimicking the effect of a colder or warmer EOS, the models favor those that are colder than SCvH-I; this class of EOS is also favored by shock experiments. The models in this scenario have more modest deep superadiabaticities such that the envelope cools more gradually and the deep

  20. Kepler-91b: a planet at the end of its life. Planet and giant host star properties via light-curve variations

    NASA Astrophysics Data System (ADS)

    Lillo-Box, J.; Barrado, D.; Moya, A.; Montesinos, B.; Montalbán, J.; Bayo, A.; Barbieri, M.; Régulo, C.; Mancini, L.; Bouy, H.; Henning, T.

    2014-02-01

    Context. The evolution of planetary systems is intimately linked to the evolution of their host stars. Our understanding of the whole planetary evolution process is based on the wide planet diversity observed so far. Only a few tens of planets have been discovered orbiting stars ascending the red giant branch. Although several theories have been proposed, the question of how planets die remains open owing to the small number statistics, making it clear that the sample of planets around post-main sequence stars needs to be enlarged. Aims: In this work we study the giant star Kepler-91 (KOI-2133) in order to determine the nature of a transiting companion. This system was detected by the Kepler Space Telescope, which identified small dims in its light curve with a period of 6.246580 ± 0.000082 days. However, its planetary confirmation is needed due to the large pixel size of the Kepler camera, which can hide other stellar configurations able to mimic planet-like transit events. Methods: We analysed Kepler photometry to 1) re-calculate transit parameters; 2) study the light-curve modulations; and 3) to perform an asteroseismic analysis (accurate stellar parameter determination) by identifying solar-like oscillations on the periodogram. We also used a high-resolution and high signal-to-noise ratio spectrum obtained with the Calar Alto Fiber-fed Échelle spectrograph (CAFE) to measure stellar properties. Additionally, false-positive scenarios were rejected by obtaining high-resolution images with the AstraLux lucky imaging camera on the 2.2 m telescope at the Calar Alto Observatory. Results: We confirm the planetary nature of the object transiting the star Kepler-91 by deriving a mass of Mp=0.88+0.17-0.33 MJup and a planetary radius of Rp=1.384+0.011-0.054 RJup. Asteroseismic analysis produces a stellar radius of R⋆ = 6.30 ± 0.16 R⊙ and a mass of M⋆ = 1.31 ± 0.10 M⊙. We find that its eccentric orbit (e=0.066+0.013-0.017) is just 1.32+0.07-0.22 R⋆ away from

  1. The HARPS search for southern extra-solar planets. XXXVII. Five new long-period giant planets and a system update

    NASA Astrophysics Data System (ADS)

    Moutou, C.; Lo Curto, G.; Mayor, M.; Bouchy, F.; Benz, W.; Lovis, C.; Naef, D.; Pepe, F.; Queloz, D.; Santos, N. C.; Ségransan, D.; Sousa, S. G.; Udry, S.

    2015-04-01

    We describe radial-velocity time series obtained by HARPS on the 3.60 m telescope in La Silla (ESO, Chile) over ten years and report the discovery of five new giant exoplanets in distant orbits; these new planets orbit the stars HD 564, HD 30669, HD 108341, and BD -114672. Their periods range from 492 to 1684 days, semi-major axes range from 1.2 to 2.69 AU, and eccentricities range from 0 to 0.85. Their minimum mass ranges from 0.33 to 3.5 MJup. We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663 ± 8 and 1818 ± 25 days, orbital eccentricities of 0.14 ± 0.08 and 0.20 ± 0.04, and minimum masses of 0.36 ± 0.04 and 0.93 ± 0.06 MJup. Finally, we report the discovery of a new hot-Jupiter planet around an active star, HD 103720; the planet has a period of 4.5557 ± 0.0001 days and a minimum mass of 0.62 ± 0.025 MJup. We discuss the fundamental parameters of these systems and limitations due to stellar activity in quiet stars with typical 2 m s-1 radial velocity precision. Based on observations made with the HARPS instrument on the ESO 3.6 m telescope at La Silla (Chile), under the GTO program ID 072.C-0488, 183.C-0972 and the regular programs: 085.C-0019, 087.C-0831, 089.C-0732, 090.C-0421, 091.C-0034, and 092.C-0721.Figures 8 and 9 and Tables 4-9 are available in electronic form at http://www.aanda.org

  2. MINIMUM CORE MASSES FOR GIANT PLANET FORMATION WITH REALISTIC EQUATIONS OF STATE AND OPACITIES

    SciTech Connect

    Piso, Ana-Maria A.; Murray-Clay, Ruth A.; Youdin, Andrew N.

    2015-02-20

    Giant planet formation by core accretion requires a core that is sufficiently massive to trigger runaway gas accretion in less than the typical lifetime of protoplanetary disks. We explore how the minimum required core mass, M {sub crit}, depends on a non-ideal equation of state (EOS) and on opacity changes due to grain growth across a range of stellocentric distances from 5-100 AU. This minimum M {sub crit} applies when planetesimal accretion does not substantially heat the atmosphere. Compared to an ideal gas polytrope, the inclusion of molecular hydrogen (H{sub 2}) dissociation and variable occupation of H{sub 2} rotational states increases M {sub crit}. Specifically, M {sub crit} increases by a factor of ∼2 if the H{sub 2} spin isomers, ortho- and parahydrogen, are in thermal equilibrium, and by a factor of ∼2-4 if the ortho-to-para ratio is fixed at 3:1. Lower opacities due to grain growth reduce M {sub crit}. For a standard disk model around a Solar mass star, we calculate M {sub crit} ∼ 8 M {sub ⊕} at 5 AU, decreasing to ∼5 M {sub ⊕} at 100 AU, for a realistic EOS with an equilibrium ortho-to-para ratio and for grain growth to centimeter-sizes. If grain coagulation is taken into account, M {sub crit} may further reduce by up to one order of magnitude. These results for the minimum critical core mass are useful for the interpretation of surveys that find exoplanets at a range of orbital distances.

  3. Bringing the Excitement of Exploring Mars and the Giant Planets to Educators and the Public

    NASA Astrophysics Data System (ADS)

    Morrow, C. A.; Dusenbery, P. B.; Harold, J.

    2003-05-01

    We are living in a wonderful era of planetary exploration. In 2004 alone, two rovers will land on Mars and the Cassini-Huygens mission will arrive in the Saturn system for an extended 4-year tour. These events will bring much public attention and provide excellent reasons for substantive educational outreach to educators and the public. The Space Science Institute (SSI) of Boulder, CO and collaborators are responding with a comprehensive array of funded and proposed projects. These include the refurbishment and redeployment of the 5000 sq. ft MarsQuest national traveling exhibition, the launch of a 600 sq. ft. "mini-MarsQuest" called Destination Mars, the launch of an interactive website called "MarsQuest Online" (in partnership with TERC and JPL), a variety of workshops for teachers, museum educators, and planetarians (in partnership with "To Mars with MER", and JPL), and the development of a "Family Guide to Mars" for use by adults and children in informal learning settings. SSI is also proposing to develop another national traveling exhibition called "Giant Planets: Exploring the Outer Solar System". This exhibit (envisioned to be 3500 sq.ft.) and its educational program will take advantage of the excitement generated by the Cassini mission and origins-related research. Its education program will also benefit from SSI having led the development of the "Saturn Educator Guide" - a JPL-sponsored resource for teachers in grades 5 and up. This paper will provide an overview of our resources in planetary science education and communicate the valuable lessons we've learned about their design, development and dissemination. SSI's educational endeavors related to planetary science have been funded by several NASA and NSF grants and contracts.

  4. Cloudless Atmospheres for L/T Dwarfs and Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Tremblin, P.; Amundsen, D. S.; Chabrier, G.; Baraffe, I.; Drummond, B.; Hinkley, S.; Mourier, P.; Venot, O.

    2016-01-01

    The admitted, conventional scenario to explain the complex spectral evolution of brown dwarfs (BDs) since their first detection 20 years ago has always been the key role played by micron-size condensates, called "dust" or "clouds," in their atmosphere. This scenario, however, faces major problems, in particular the J-band brightening and the resurgence of FeH absorption at the L to T transition, and a physical first-principle understanding of this transition is lacking. In this Letter, we propose a new, completely different explanation for BD and extrasolar giant planet (EGP) spectral evolution, without the need to invoke clouds. We show that, due to the slowness of the CO/ CH4 and N2/NH3 chemical reactions, brown dwarf (L and T, respectively) and EGP atmospheres are subject to a thermo-chemical instability similar in nature to the fingering or chemical convective instability present in Earth oceans and at the Earth core/mantle boundary. The induced small-scale turbulent energy transport reduces the temperature gradient in the atmosphere, explaining the observed increase in near-infrared J-H and J-K colors of L dwarfs and hot EGPs, while a warming up of the deep atmosphere along the L to T transition, as the CO/CH4 instability vanishes, naturally solves the two aforementioned puzzles, and provides a physical explanation of the L to T transition. This new picture leads to a drastic revision of our understanding of BD and EGP atmospheres and their evolution.

  5. Cloudless Atmospheres for L/T Dwarfs and Extrasolar Giant Planets

    NASA Astrophysics Data System (ADS)

    Tremblin, P.; Amundsen, D. S.; Chabrier, G.; Baraffe, I.; Drummond, B.; Hinkley, S.; Mourier, P.; Venot, O.

    2016-02-01

    The admitted, conventional scenario to explain the complex spectral evolution of brown dwarfs (BDs) since their first detection 20 years ago has always been the key role played by micron-size condensates, called “dust” or “clouds,” in their atmosphere. This scenario, however, faces major problems, in particular the J-band brightening and the resurgence of FeH absorption at the L to T transition, and a physical first-principle understanding of this transition is lacking. In this Letter, we propose a new, completely different explanation for BD and extrasolar giant planet (EGP) spectral evolution, without the need to invoke clouds. We show that, due to the slowness of the CO/CH4 and N2/NH3 chemical reactions, brown dwarf (L and T, respectively) and EGP atmospheres are subject to a thermo-chemical instability similar in nature to the fingering or chemical convective instability present in Earth oceans and at the Earth core/mantle boundary. The induced small-scale turbulent energy transport reduces the temperature gradient in the atmosphere, explaining the observed increase in near-infrared J-H and J-K colors of L dwarfs and hot EGPs, while a warming up of the deep atmosphere along the L to T transition, as the CO/CH4 instability vanishes, naturally solves the two aforementioned puzzles, and provides a physical explanation of the L to T transition. This new picture leads to a drastic revision of our understanding of BD and EGP atmospheres and their evolution.

  6. ON THE SECULAR BEHAVIOR OF DUST PARTICLES IN AN ECCENTRIC PROTOPLANETARY DISK WITH AN EMBEDDED MASSIVE GAS GIANT PLANET

    SciTech Connect

    Hsieh, He-Feng; Gu, Pin-Gao E-mail: gu@asiaa.sinica.edu.tw

    2012-12-01

    We investigate the dust velocity and spatial distribution in an eccentric protoplanetary disk under the secular gravitational perturbation of an embedded planet of about 5 Jupiter masses. We first employ the FARGO code to obtain the two-dimensional density and velocity profiles of the eccentric gas disk exterior to the gap opened up by the embedded planet in the quasi-steady state. We then apply the secular perturbation theory and incorporate the gas drag to estimate the dust velocity and density on a secular timescale. The dust-to-gas ratio of the unperturbed disk is simply assumed to be 0.01. In our fiducial disk model with the planet at 5 AU, we find that 0.01 cm to 1 m sized dust particles are well coupled to the gas. Consequently, the particles behave similarly to the gas and exhibit asymmetric dynamics as a result of eccentric orbits. The dust surface density is enhanced around the apocenter of the disk. However, for the case of a low-density gaseous disk (called the 'transition disk' henceforth in this work) harboring the planet at 100 AU, the azimuthal distributions of dust of various sizes can deviate significantly. Overall, the asymmetric structure exhibits a phase correlation between the gas velocity fields and dust density distribution. Therefore, our study potentially provides a reality check as to whether an asymmetric disk gap detected at submillimeter and centimeter wavelengths is a signpost of a massive gas giant planet.

  7. A Spitzer Transit of the Most Inflated Planet Known, Around an Extremely Bright Sub-giant Star

    NASA Astrophysics Data System (ADS)

    Beatty, Thomas; Collins, Karen; Colon, Knicole; James, David; Kriedberg, Laura; Pepper, Joshua; Rodriguez, Joseph; Siverd, Robert; Stassun, Keivan; Stevens, Daniel

    2015-10-01

    KELT-11b is a newly discovered transiting Saturn-mass planet (Mp~0.22MJ) that promises to become a unique benchmark. KELT-11b orbits HD 93396,the second brightest star in the near-IR (K=6.122) and the third brightest star in the optical (V=8.04) to host a transiting giant planet. This makes KELT-11 comparable to the well-studied benchmarks HD 189733 and HD 209458. But unlike these other bright systems, KELT-11b's host star is a sub-giant, with log(g)~3.7. Thus KELT-11b is the first transiting giant planet known around a sub-giant star bright enough for precise follow-up observations. Furthermore, KELT-11b is the most inflated planet known, with the lowest surface gravity (log[g]~2.5) of any transiting planet. This makes it an exciting target for atmospheric characterization and studying the effect of post main-sequence evolution of a host star on a hot Jupiter. But to correctly interpret any follow-up observations, we will first need to measure accurate stellar and planetary parameters for the system via a precise transit observation. Unfortunately, this is effectively impossible to do from the ground. Spitzer's ability to provide high precision continuous photometry provides the only current way in which we may precisely observe a complete transit of KELT-11b. We therefore propose for 15.5 hours, to observe a single transit KELT-11b at 3.6um. This would reduce the uncertainties on the transit depth and stellar density by at least a factor of twenty, and will improve the model-derived stellar mass by at least a factor of ten, compared to ground-based observations. This will serve two goals. First, it will be a valuable legacy to the community, by providing a precise set of system parameters that will enable future observation and interpretation of this unique, bright, system. Second, an observation of a transit will allow us to strongly constrain the mass of KELT-11, and thus help resolve the disagreement over the true masses of the 'retired A stars' radial

  8. ON THE VARIATION OF ZONAL GRAVITY COEFFICIENTS OF A GIANT PLANET CAUSED BY ITS DEEP ZONAL FLOWS

    SciTech Connect

    Kong Dali; Zhang Keke; Schubert, Gerald E-mail: kzhang@ex.ac.uk

    2012-04-01

    Rapidly rotating giant planets are usually marked by the existence of strong zonal flows at the cloud level. If the zonal flow is sufficiently deep and strong, it can produce hydrostatic-related gravitational anomalies through distortion of the planet's shape. This paper determines the zonal gravity coefficients, J{sub 2n}, n = 1, 2, 3, ..., via an analytical method taking into account rotation-induced shape changes by assuming that a planet has an effective uniform density and that the zonal flows arise from deep convection and extend along cylinders parallel to the rotation axis. Two different but related hydrostatic models are considered. When a giant planet is in rigid-body rotation, the exact solution of the problem using oblate spheroidal coordinates is derived, allowing us to compute the value of its zonal gravity coefficients J-bar{sub 2n}, n=1,2,3,..., without making any approximation. When the deep zonal flow is sufficiently strong, we develop a general perturbation theory for estimating the variation of the zonal gravity coefficients, {Delta}J{sub 2n}=J{sub 2n}-J-bar{sub 2n}, n=1,2,3,..., caused by the effect of the deep zonal flows for an arbitrarily rapidly rotating planet. Applying the general theory to Jupiter, we find that the deep zonal flow could contribute up to 0.3% of the J{sub 2} coefficient and 0.7% of J{sub 4}. It is also found that the shape-driven harmonics at the 10th zonal gravity coefficient become dominant, i.e., {Delta}J{sub 2n}>=J-bar{sub 2n} for n {>=} 5.

  9. Some inner satellites of giant planets are still outgassing: Triton, Enceladus, Io

    NASA Astrophysics Data System (ADS)

    Kochemasov, Gennady G.

    2010-05-01

    Process of atmospheric formation in the Solar system continues. There are three celestial bodies (except Earth) still emitting considerable amounts of volatiles though these bodies' masses do not allow keeping appreciable amounts of emitted volatiles in their vicinity and creating real atmospheres. It was earlier shown that the wave oscillations in form of stationary waves more or less rapidly changing their phases (plus to minus and inversely) sweep out volatiles from planetary depths [1]. These stationary waves, proportional in their amplitudes to the radii of tectonic granules (Mercury πR/16, Venus πR/6, Earth πR/4, Mars πR/2) and inversely proportional to orbital frequencies, form the planetary surface relief range of which increases with the solar distance [2]. In the opposite direction increases the sweeping out force of these waves and, consequently, atmospheric masses increase [3]. In the satellite systems of the outer giant planets this regularity is preserved in that the inner satellites (even small as Enceladus) surprisingly continue to push out volatiles. To do so, really very thorough washing out of entire body should be executed by very fine oscillations. Very fast orbits (Triton - 5.9 days; Enceladus - 1.37 d.; Io - 1.769 d.) secure this. Titan with rather fast orbit (16 d.) has enough mass and gravity to create and keep an atmosphere. Triton has a tenuous nitrogen atmosphere with small amounts of methane. A part of its crust (the southern "continental" segment) is dotted with geysers believed to erupt nitrogen with some admixture of dust entrained from beneath the surface. The geyser plumes are up to 8 km high. There are many streaks of dark material laid down by the geyser activity. Enceladus spews out icy material from the south pole region called "Tiger stripes". Some of the tiny ice particles go into Saturn orbit, forming the doughnut-shaped E ring ("detached Enceladus' atmosphere"). Io has at the moment more than 150 active volcanoes making

  10. Turbulent convection in an anelastic rotating sphere: A model for the circulation on the giant planets

    NASA Astrophysics Data System (ADS)

    Kaspi, Yohai

    This thesis studies the dynamics of a rotating compressible gas sphere, driven by internal convection, as a model for the dynamics on the giant planets. We develop a new general circulation model for the Jovian atmosphere, based on the MITgcm dynamical core augmenting the nonhydrostatic model. The grid extends deep into the planet's interior allowing the model to compute the dynamics of a whole sphere of gas rather than a spherical shell (including the strong variations in gravity and the equation of state). Different from most previous 3D convection models, this model is anelastic rather than Boussinesq and thereby incorporates the full density variation of the planet. We show that the density gradients caused by convection drive the system away from an isentropic and therefore barotropic state as previously assumed, leading to significant baroclinic shear. This shear is concentrated mainly in the upper levels and associated with baroclinic compressibility effects. The interior flow organizes in large cyclonically rotating columnar eddies parallel to the rotation axis, which drive upgradient angular momentum eddy fluxes, generating the observed equatorial superrotation. Heat fluxes align with the axis of rotation, contributing to the observed flat meridional emission. We show the transition from weak convection cases with symmetric spiraling columnar modes similar to those found in previous analytic linear theory, to more turbulent cases which exhibit similar, though less regular and solely cyclonic, convection columns which manifest on the surface in the form of waves embedded within the superrotation. We develop a mechanical understanding of this system and scaling laws by studying simpler configurations and the dependence on physical properties such as the rotation period, bottom boundary location and forcing structure. These columnar cyclonic structures propagate eastward, driven by dynamics similar to that of a Rossby wave except that the restoring planetary

  11. Model Atmospheres for Massive Gas Giants with Thick Clouds: Application to the HR 8799 Planets and Predictions for Future Detections

    NASA Astrophysics Data System (ADS)

    Madhusudhan, Nikku; Burrows, Adam; Currie, Thayne

    2011-08-01

    We have generated an extensive new suite of massive giant planet atmosphere models and used it to obtain fits to photometric data for the planets HR 8799b, c, and d. We consider a wide range of cloudy and cloud-free models. The cloudy models incorporate different geometrical and optical thicknesses, modal particle sizes, and metallicities. For each planet and set of cloud parameters, we explore grids in gravity and effective temperature, with which we determine constraints on the planet's mass and age. Our new models yield statistically significant fits to the data, and conclusively confirm that the HR 8799 planets have much thicker clouds than those required to explain data for typical L and T dwarfs. Both models with (1) physically thick forsterite clouds and a 60 μm modal particle size and (2) clouds made of 1 μm sized pure iron droplets and 1% supersaturation fit the data. Current data are insufficient to accurately constrain the microscopic cloud properties, such as composition and particle size. The range of best-estimated masses for HR 8799b, HR 8799c, and HR 8799d conservatively span 2-12 MJ , 6-13 MJ , and 3-11 MJ , respectively, and imply coeval ages between ~10 and ~150 Myr, consistent with previously reported stellar ages. The best-fit temperatures and gravities are slightly lower than values obtained by Currie et al. using even thicker cloud models. Finally, we use these models to predict the near-to-mid-IR colors of soon-to-be imaged planets. Our models predict that planet-mass objects follow a locus in some near-to-mid-IR color-magnitude diagrams that is clearly separable from the standard L/T dwarf locus for field brown dwarfs.

  12. MODEL ATMOSPHERES FOR MASSIVE GAS GIANTS WITH THICK CLOUDS: APPLICATION TO THE HR 8799 PLANETS AND PREDICTIONS FOR FUTURE DETECTIONS

    SciTech Connect

    Madhusudhan, Nikku; Burrows, Adam; Currie, Thayne E-mail: burrows@astro.princeton.edu

    2011-08-10

    We have generated an extensive new suite of massive giant planet atmosphere models and used it to obtain fits to photometric data for the planets HR 8799b, c, and d. We consider a wide range of cloudy and cloud-free models. The cloudy models incorporate different geometrical and optical thicknesses, modal particle sizes, and metallicities. For each planet and set of cloud parameters, we explore grids in gravity and effective temperature, with which we determine constraints on the planet's mass and age. Our new models yield statistically significant fits to the data, and conclusively confirm that the HR 8799 planets have much thicker clouds than those required to explain data for typical L and T dwarfs. Both models with (1) physically thick forsterite clouds and a 60 {mu}m modal particle size and (2) clouds made of 1 {mu}m sized pure iron droplets and 1% supersaturation fit the data. Current data are insufficient to accurately constrain the microscopic cloud properties, such as composition and particle size. The range of best-estimated masses for HR 8799b, HR 8799c, and HR 8799d conservatively span 2-12 M{sub J} , 6-13 M{sub J} , and 3-11 M{sub J} , respectively, and imply coeval ages between {approx}10 and {approx}150 Myr, consistent with previously reported stellar ages. The best-fit temperatures and gravities are slightly lower than values obtained by Currie et al. using even thicker cloud models. Finally, we use these models to predict the near-to-mid-IR colors of soon-to-be imaged planets. Our models predict that planet-mass objects follow a locus in some near-to-mid-IR color-magnitude diagrams that is clearly separable from the standard L/T dwarf locus for field brown dwarfs.

  13. Precise radial velocities of giant stars. VIII. Testing for the presence of planets with CRIRES infrared radial velocities

    NASA Astrophysics Data System (ADS)

    Trifonov, Trifon; Reffert, Sabine; Zechmeister, Mathias; Reiners, Ansgar; Quirrenbach, Andreas

    2015-10-01

    Context. We have been monitoring 373 very bright (V ≤ 6 mag) G and K giants with high precision optical Doppler spectroscopy for more than a decade at Lick Observatory. Our goal was to discover planetary companions around those stars and to better understand planet formation and evolution around intermediate-mass stars. However, in principle, long-term, g-mode nonradial stellar pulsations or rotating stellar features, such as spots, could effectively mimic a planetary signal in the radial velocity data. Aims: Our goal is to compare optical and infrared radial velocities for those stars with periodic radial velocity patterns and to test for consistency of their fitted radial velocity semiamplitudes. Thereby, we distinguish processes intrinsic to the star from orbiting companions as reason for the radial velocity periodicity observed in the optical. Methods: Stellar spectra with high spectral resolution have been taken in the H-band with the CRIRES near-infrared spectrograph at ESO's VLT for 20 stars of our Lick survey. Radial velocities are derived using many deep and stable telluric CO2 lines for precise wavelength calibration. Results: We find that the optical and near-infrared radial velocities of the giant stars in our sample are consistent. We present detailed results for eight stars in our sample previously reported to have planets or brown dwarf companions. All eight stars passed the infrared test. Conclusions: We conclude that the planet hypothesis provides the best explanation for the periodic radial velocity patterns observed for these giant stars. Based on observations collected at the European Southern Observatory, Chile, under program IDs 088.D-0132, 089.D-0186, 090.D-0155 and 091.D-0365.Appendix A is available in electronic form at http://www.aanda.org

  14. Laser-driven shock experiments in pre-compressed water: Implications for magnetic field generation in Icy Giant planets

    SciTech Connect

    Lee, K; Benedetti, L R; Jeanloz, R; Celliers, P M; Eggert, J H; Hicks, D G; Moon, S J; Mackinnon, A; Henry, E; Koenig, M; Benuzzi-Mounaix, A; Collins, G W

    2005-11-10

    Laser-driven shock compression of pre-compressed water (up to 1 GPa precompression) produces high-pressure, -temperature conditions in the water inducing two optical phenomena: opacity and reflectivity in the initially transparent water. The onset of reflectivity at infrared wavelengths can be interpreted as a semi-conductor to electronic conductor transition in water and is found at pressures above {approx}130 GPa for single-shocked samples pre-compressed to 1 GPa. This electronic conduction provides an additional contribution to the conductivity required for magnetic field generation in Icy Giant planets like Uranus and Neptune.

  15. USING SCHUMANN RESONANCE MEASUREMENTS FOR CONSTRAINING THE WATER ABUNDANCE ON THE GIANT PLANETS-IMPLICATIONS FOR THE SOLAR SYSTEM'S FORMATION

    SciTech Connect

    Simoes, Fernando; Pfaff, Robert; Klenzing, Jeffrey; Freudenreich, Henry; Bromund, Kenneth; Martin, Steven; Rowland, Douglas; Takahashi, Yukihiro; Yair, Yoav

    2012-05-01

    The formation and evolution of the solar system is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the solar system is therefore important for understanding not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new remote sensing technique to infer the outer planets' water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

  16. Using Schumann Resonance Measurements for Constraining the Water Abundance on the Giant Planets - Implications for the Solar System Formation

    NASA Technical Reports Server (NTRS)

    Simoes, Fernando; Pfaff, Robert; Hamelin, Michel; Klenzing, Jeffrey; Freudenreich, Henry; Beghin, Christian; Berthelier, Jean-Jacques; Bromund, Kenneth; Grard, Rejean; Lebreton, Jean-Pierre; Martin, Steven; Rowland, Douglas; Sentman, Davis; Takahashi, Yukihiro; Yair, Yoav

    2012-01-01

    The formation and evolution of the Solar System is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the Solar System is therefore important to understand not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new, remote sensing technique to infer the outer planets water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

  17. The Occurrence of Additional Giant Planets Inside the Water-Ice Line in Systems with Hot Jupiters: Evidence Against High-Eccentricity Migration

    NASA Astrophysics Data System (ADS)

    Schlaufman, Kevin C.; Winn, Joshua N.

    2016-07-01

    The origin of Jupiter-mass planets with orbital periods of only a few days is still uncertain. It is widely believed that these planets formed near the water-ice line of the protoplanetary disk, and subsequently migrated into much smaller orbits. Most of the proposed migration mechanisms can be classified either as disk-driven migration, or as excitation of a very high eccentricity followed by tidal circularization. In the latter scenario, the giant planet that is destined to become a hot Jupiter spends billions of years on a highly eccentric orbit, with apastron near the water-ice line. Eventually, tidal dissipation at periastron shrinks and circularizes the orbit. If this is correct, then it should be especially rare for hot Jupiters to be accompanied by another giant planet interior to the water-ice line. Using the current sample of giant planets discovered with the Doppler technique, we find that hot Jupiters with P orb < 10 days are no more or less likely to have exterior Jupiter-mass companions than longer-period giant planets with P orb ≥ 10 days. This result holds for exterior companions both inside and outside of the approximate location of the water-ice line. These results are difficult to reconcile with the high-eccentricity migration scenario for hot Jupiter formation.

  18. INTERACTION OF A GIANT PLANET IN AN INCLINED ORBIT WITH A CIRCUMSTELLAR DISK

    SciTech Connect

    Marzari, F.; Nelson, Andrew F. E-mail: andy.nelson@lanl.go

    2009-11-10

    We investigate the dynamical evolution of a Jovian-mass planet injected into an orbit highly inclined with respect to its nesting gaseous disk. Planet-planet scattering induced by convergent planetary migration and mean motion resonances may push a planet into such an out-of-plane configuration with inclinations as large as 20{sup 0}-30{sup 0}. In this scenario, the tidal interaction of the planet with the disk is more complex and, in addition to the usual Lindblad and corotation resonances, it also involves inclination resonances responsible for bending waves. We have performed three-dimensional hydrodynamic simulations of the disk and of its interactions with the planet with a smoothed particle hydrodynamics code. A main result is that the initial large eccentricity and inclination of the planetary orbit are rapidly damped on a timescale of the order of 10{sup 3} yr, almost independently of the initial semimajor axis and eccentricity of the planet. The disk is warped in response to the planet perturbations and it precesses. Inward migration also occurs when the planet is inclined, and it has a drift rate that is intermediate between type I and type II migration. The planet is not able to open a gap until its inclination becomes lower than approx10{sup 0}, when it also begins to accrete a significant amount of mass from the disk.

  19. Atmospheric circulation of brown dwarfs and directly imaged extrasolar giant planets with active clouds

    NASA Astrophysics Data System (ADS)

    Tan, Xianyu; Showman, Adam

    2016-10-01

    Observational evidence have suggested active meteorology in the atmospheres of brown dwarfs (BDs) and directly imaged extrasolar giant planets (EGPs). In particular, a number of surveys for brown dwarfs showed that near-IR brightness variability is common for L and T dwarfs. Directly imaged EGPs share similar observations, and can be viewed as low-gravity versions of BDs. Clouds are believed to play the major role in shaping the thermal structure, dynamics and near-IR flux of these atmospheres. So far, only a few studies have been devoted to atmospheric circulation and the implications for observations of BDs and directly EGPs, and yet no global model includes a self-consistent active cloud formation. Here we present preliminary results from the first global circulation model applied to BDs and directly imaged EGPs that can properly treat absorption and scattering of radiation by cloud particles. Our results suggest that horizontal temperature differences on isobars can reach up to a few hundred Kelvins, with typical horizontal length scale of the temperature and cloud patterns much smaller than the radius of the object. The combination of temperature anomaly and cloud pattern can result in moderate disk-integrated near-IR flux variability. Wind speeds can reach several hundred meters per second in cloud forming layers. Unlike Jupiter and Saturn, we do not observe stable zonal jet/banded patterns in our simulations. Instead, our simulated atmospheres are typically turbulent and dominated by transient vortices. The circulation is sensitive to the parameterized cloud microphysics. Under some parameter combinations, global-scale atmospheric waves can be triggered and maintained. These waves induce global-scale temperature anomalies and cloud patterns, causing large (up to several percent) disk-integrated near-IR flux variability. Our results demonstrate that the commonly observed near-IR brightness variability for BDs and directly imaged EGPs can be explained by the

  20. Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations

    NASA Astrophysics Data System (ADS)

    Gomes-Júnior, A. R.; Assafin, M.; Vieira-Martins, R.; Arlot, J.-E.; Camargo, J. I. B.; Braga-Ribas, F.; da Silva Neto, D. N.; Andrei, A. H.; Dias-Oliveira, A.; Morgado, B. E.; Benedetti-Rossi, G.; Duchemin, Y.; Desmars, J.; Lainey, V.; Thuillot, W.

    2015-08-01

    Context. The irregular satellites of the giant planets are believed to have been captured during the evolution of the solar system. Knowing their physical parameters, such as size, density, and albedo is important for constraining where they came from and how they were captured. The best way to obtain these parameters are observations in situ by spacecrafts or from stellar occultations by the objects. Both techniques demand that the orbits are well known. Aims: We aimed to obtain good astrometric positions of irregular satellites to improve their orbits and ephemeris. Methods: We identified and reduced observations of several irregular satellites from three databases containing more than 8000 images obtained between 1992 and 2014 at three sites (Observatório do Pico dos Dias, Observatoire de Haute-Provence, and European Southern Observatory - La Silla). We used the software Platform for Reduction of Astronomical Images Automatically (PRAIA) to make the astrometric reduction of the CCD frames. The UCAC4 catalog represented the International Celestial Reference System in the reductions. Identification of the satellites in the frames was done through their ephemerides as determined from the SPICE/NAIF kernels. Some procedures were followed to overcome missing or incomplete information (coordinates, date), mostly for the older images. Results: We managed to obtain more than 6000 positions for 18 irregular satellites: 12 of Jupiter, 4 of Saturn, 1 of Uranus (Sycorax), and 1 of Neptune (Nereid). For some satellites the number of obtained positions is more than 50% of what was used in earlier orbital numerical integrations. Conclusions: Comparison of our positions with recent JPL ephemeris suggests there are systematic errors in the orbits for some of the irregular satellites. The most evident case was an error in the inclination of Carme. Position tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http

  1. Giant-Planet Chemistry: Ammonium Hydrosulfide (NH4SH), Its IR Spectra and Thermal and Radiolytic Stabilities

    NASA Technical Reports Server (NTRS)

    Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.

    2015-01-01

    Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10-160 K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing ions. Crystalline NH4SH was amorphized during irradiation at all temperatures studied with the rate being the fastest at the lowest temperatures. Irradiation of amorphous NH4SH at approximately 10-75 K showed that 60-80% of the NH4 + remained when equilibrium was reached, and that NH4SH destruction rates were relatively constant within this temperature range. Irradiations at higher temperatures produced different dose dependence and were accompanied by pressure outbursts that, in some cases, fractured the ice. The thermal stability of irradiated NH4SH was found to be greater than that of unirradiated NH4SH, suggesting that an irradiated giant-planet cloud precipitate can exist at temperatures and altitudes not previously considered.

  2. Amateur - professional collaborations in Giant Planets Atmospheres Research through the Planetary Virtual Observatory of the International Outer Planets Watch (PVOL - IOPW)

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Legarreta, J.; Sánchez-Lavega, A.

    2015-10-01

    The atmospheres node of the International Outer Planets Watch (IOPW) maintains a large database of observations of the Giant Planets called Planetary Virtual Observatory Laboratory (PVOL) [1]. This image repository is contributed by amateur astronomers worldwide and its images keep a record of atmospheric activity on Jupiter, Saturn and Uranus over the years. PVOL was created as an unfunded project that has been online since 2004. Its data content has been growing ever since then, now containing about 25,000 image files that cover the period 2000-2015. The main characteristic of PVOL, when compared with other amateur images repositories, is that it is built as a database with different searching tools. This characteristic has made PVOL an important research tool over the years for various scientific teams. Here we update the description of the data in PVOL and we discuss new development plans in the context of the Virtual European Solar and Planetary Access (VESPA) collaboration which will bring life to a Virtual Observatory for Planetary Sciences. The database is available in the following address:

  3. Giant planets around two intermediate-mass evolved stars and confirmation of the planetary nature of HIP 67851c

    NASA Astrophysics Data System (ADS)

    Jones, M. I.; Jenkins, J. S.; Rojo, P.; Olivares, F.; Melo, C. H. F.

    2015-08-01

    Context. Precision radial velocities are required to discover and characterize exoplanets. Optical spectra that exhibit many hundreds of absorption lines can allow the m s-1 precision levels required for this work. After the main-sequence, intermediate-mass stars expand and rotate more slowly than their progenitors, thus, thousands of spectral lines appear in the optical region, permitting the search for Doppler signals in these types of stars. Aims: In 2009, we began the EXPRESS program, aimed at detecting substellar objects around evolved stars, and studying the effects of the mass and evolution of the host star on their orbital and physical properties. Methods: We obtained precision radial velocity measurements for the giant stars HIP 65891 and HIP 107773, from CHIRON and FEROS spectra. Also, we obtained new radial velocity epochs for the star HIP 67851, which is known to host a planetary system. Results: We present the discovery of two giant planets around the intermediate-mass evolved star HIP 65891 and HIP 107773. The best Keplerian fit to the HIP 65891 and HIP 107773 radial velocities leads to the following orbital parameters: P = 1084.5 d; mb sini = 6.0 MJ ; e = 0.13 and P = 144.3 d; mb sini = 2.0 MJ ; e = 0.09, respectively. In addition, we confirm the planetary nature of the outer object orbiting the giant star HIP 67851. The orbital parameters of HIP 67851 c are: P = 2131.8 d, mc sini = 6.0MJ, and e = 0.17. Conclusions: With masses of 2.5 M⊙ and 2.4 M⊙, HIP 65891 and HIP 107773 are two of the most massive planet-hosting stars. Additionally, HIP 67851 is one of five giant stars that are known to host a planetary system having a close-in planet (a< 0.7 AU). Based on the evolutionary states of those five stars, we conclude that close-in planets do exist in multiple systems around subgiants and slightly evolved giants stars, but most likely they are subsequently destroyed by the stellar envelope during the ascent of the red giant branch phase. Based on

  4. Decoupling of a giant planet from its disk in an inclined binary system

    NASA Astrophysics Data System (ADS)

    Picogna, G.; Marzari, F.

    2015-11-01

    Context. We explore the dynamical evolution of a planet that is embedded in a circumstellar disk, as part of a binary system where the orbital plane of the companion star is significantly tilted with respect to the initial disk plane. Aims: Our aim is to test whether the planet remains within the disk and continues to migrate towards the star in a Type I/II mode, in spite of the secular perturbations of the companion star. Our findings, could explain why observed exoplanets have significant inclination in relation to the equatorial plane of their host star. Methods: We used two different smoothed particle hydrodynamic codes, VINE and PHANTOM, to model the evolution of a star+disk+planet system with a companion star over time. Results: After an initial coupled evolution, the inclinations of the disk and the planet begin to differ significantly. The period of oscillation of the disk inclination, in relation to the initial plane, becomes shorter for the planet, which evolves independently after about 104 yr, following a perturbed N-body behaviour. However, the planet continues to migrate towards the star because, during its orbital motion, it crosses the disk plane, and friction with the gas causes angular momentum loss. Conclusions: In a significantly inclined binary system, disks and planets are not dynamically coupled for small binary separations but evolve almost independently. The planet abandons the disk, and because of the onset of a significant mutual inclination, it interacts with the gas only when its orbit intersects the disk plane. The drift of the planet towards the star is not due to Type I/II, where the planet is embedded in the disk, but to the friction with the gas while crossing the disk.

  5. Revisiting the Microlensing Event OGLE 2012-BLG-0026: A Solar Mass Star with Two Cold Giant Planets

    NASA Astrophysics Data System (ADS)

    Beaulieu, J.-P.; Bennett, D. P.; Batista, V.; Fukui, A.; Marquette, J.-B.; Brillant, S.; Cole, A. A.; Rogers, L. A.; Sumi, T.; Abe, F.; Bhattacharya, A.; Koshimoto, N.; Suzuki, D.; Tristram, P. J.; Han, C.; Gould, A.; Pogge, R.; Yee, J.

    2016-06-01

    Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 ± 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B&C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of a ˜4-9 Gyr lens star of M lens = 1.06 ± 0.05 M ⊙ at a distance of D lens = 4.0 ± 0.3 kpc, orbited by two giant planets of 0.145 ± 0.008 M Jup and 0.86 ± 0.06 M Jup, with projected separations of 4.0 ± 0.5 au and 4.8 ± 0.7 au, respectively. Because the lens is brighter than the source star by 16 ± 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8-10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.

  6. Revisiting the Microlensing Event OGLE 2012-BLG-0026: A Solar Mass Star with Two Cold Giant Planets

    NASA Technical Reports Server (NTRS)

    Beaulieu, J.-P.; Bennett, D. P.; Batista, V.; Fukui, A.; Marquette, J.-B.; Brillant, S.; Cole, A. A.; Rogers, L. A.; Sumi, T.; Abe, F.

    2016-01-01

    Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 +/- 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B and C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of an approximately 4-9 Gyr lens star of M(sub lens) = 1.06 +/- 0.05 solar mass at a distance of D(sub lens) = 4.0 +/- 0.3 kpc, orbited by two giant planets of 0.145 +/- 0.008 M(sub Jup) and 0.86 +/- 0.06 M(sub Jup), with projected separations of 4.0 +/- 0.5 au and 4.8 +/- 0.7 au, respectively. Because the lens is brighter than the source star by 16 +/- 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8-10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.

  7. Revisiting the Microlensing Event OGLE 2012-BLG-0026: A Solar Mass Star with Two Cold Giant Planets

    NASA Astrophysics Data System (ADS)

    Beaulieu, J.-P.; Bennett, D. P.; Batista, V.; Fukui, A.; Marquette, J.-B.; Brillant, S.; Cole, A. A.; Rogers, L. A.; Sumi, T.; Abe, F.; Bhattacharya, A.; Koshimoto, N.; Suzuki, D.; Tristram, P. J.; Han, C.; Gould, A.; Pogge, R.; Yee, J.

    2016-06-01

    Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 ± 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B&C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of a ˜4–9 Gyr lens star of M lens = 1.06 ± 0.05 M ⊙ at a distance of D lens = 4.0 ± 0.3 kpc, orbited by two giant planets of 0.145 ± 0.008 M Jup and 0.86 ± 0.06 M Jup, with projected separations of 4.0 ± 0.5 au and 4.8 ± 0.7 au, respectively. Because the lens is brighter than the source star by 16 ± 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8–10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.

  8. RADIAL VELOCITY OBSERVATIONS AND LIGHT CURVE NOISE MODELING CONFIRM THAT KEPLER-91b IS A GIANT PLANET ORBITING A GIANT STAR

    SciTech Connect

    Barclay, Thomas; Huber, Daniel; Rowe, Jason F.; Quintana, Elisa V.; Foreman-Mackey, Daniel

    2015-02-10

    Kepler-91b is a rare example of a transiting hot Jupiter around a red giant star, providing the possibility to study the formation and composition of hot Jupiters under different conditions compared to main-sequence stars. However, the planetary nature of Kepler-91b, which was confirmed using phase-curve variations by Lillo-Box et al., was recently called into question based on a re-analysis of Kepler data. We have obtained ground-based radial velocity observations from the Hobby-Eberly Telescope and unambiguously confirm the planetary nature of Kepler-91b by simultaneously modeling the Kepler and radial velocity data. The star exhibits temporally correlated noise due to stellar granulation which we model as a Gaussian Process. We hypothesize that it is this noise component that led previous studies to suspect Kepler-91b to be a false positive. Our work confirms the conclusions presented by Lillo-Box et al. that Kepler-91b is a 0.73 ± 0.13 M {sub Jup} planet orbiting a red giant star.

  9. Radial Velocity Observations and Light Curve Noise Modeling Confirm that Kepler-91b is a Giant Planet Orbiting a Giant Star

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas; Endl, Michael; Huber, Daniel; Foreman-Mackey, Daniel; Cochran, William D.; MacQueen, Phillip J.; Rowe, Jason F.; Quintana, Elisa V.

    2015-02-01

    Kepler-91b is a rare example of a transiting hot Jupiter around a red giant star, providing the possibility to study the formation and composition of hot Jupiters under different conditions compared to main-sequence stars. However, the planetary nature of Kepler-91b, which was confirmed using phase-curve variations by Lillo-Box et al., was recently called into question based on a re-analysis of Kepler data. We have obtained ground-based radial velocity observations from the Hobby-Eberly Telescope and unambiguously confirm the planetary nature of Kepler-91b by simultaneously modeling the Kepler and radial velocity data. The star exhibits temporally correlated noise due to stellar granulation which we model as a Gaussian Process. We hypothesize that it is this noise component that led previous studies to suspect Kepler-91b to be a false positive. Our work confirms the conclusions presented by Lillo-Box et al. that Kepler-91b is a 0.73 ± 0.13 M Jup planet orbiting a red giant star. Based partly on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  10. Are You There Gas? It's Me, Planet: The Effects of Gas on Growth of Gas Giant Cores through Planetesimal Accretion

    NASA Astrophysics Data System (ADS)

    Wolansky, Natania R.

    2014-04-01

    Before now, models have not been successful in predicting the rapid growth of rocky cores of gas giant planets at large separations from their host stars. Timescales for growth have far outstripped the lifetime of the gaseous disk surrounding the young star, creating a paradox between the need for the core to accrete material and the depleted supply of gas and dust. I present a model for planetary core accretion taking into account the effect of surrounding gas on the dynamics between the core and the accretable material, thus altering the characteristics of the effective cross section of accretion of the planet. By replacing the Hill radius with a wind shearing (WISH) radius, which tracks the point at which a small particle is not sheared away from a core by differential gas drag force, and by imposing additional energy constraints which determine whether a particle will successfully decouple from the gas during its encounter with the core, I recalculate the timescales of growth of a planetary core under a number of varying parameters. I apply the results to the A-type HR8799 star system, including HR8799b, c, and d, roughly 10MJ planets located at a separation of 68, 38, and 24 AU, respectively. Using the model, I reduce the "last doubling" timescales of growth predicted by classical gravitational focusing models by a factor of 1000, from 107 years to 104 years for HR8799b, c, and d, placing timescales of growth in all three cases within acceptable limits to agree with the lifetime of a gaseous disk and the deduced lifetimes of the planets. These results place within the realm of possibility that these 3 planets are formed by core accretion instead of gravitational instability. In exploring the timescales for growth of planetary cores in systems with varying parameters such as star size, disk density, and dust particle size distributions, I provide a model for predicting the possibility of driftless formation of a gas giant given the protoplanetary system

  11. WASP-92b, WASP-93b and WASP-118b: Three new transiting close-in giant planets

    NASA Astrophysics Data System (ADS)

    Hay, K. L.; Collier-Cameron, A.; Doyle, A. P.; Hébrard, G.; Skillen, I.; Anderson, D. R.; Barros, S. C. C.; Brown, D. J. A.; Bouchy, F.; Busuttil, R.; Delorme, P.; Delrez, L.; Demangeon, O.; Díaz, R. F.; Gillon, M.; Gómez Maqueo Chew, Y.; Gonzàlez, E.; Hellier, C.; Holmes, S.; Jarvis, J. F.; Jehin, E.; Joshi, Y. C.; Kolb, U.; Lendl, M.; Maxted, P. F. L.; McCormac, J.; Miller, G. R. M.; Mortier, A.; Pallé, E.; Pollacco, D.; Prieto-Arranz, J.; Queloz, D.; Ségransan, D.; Simpson, E. K.; Smalley, B.; Southworth, J.; Triaud, A. H. M. J.; Turner, O. D.; Udry, S.; Vanhuysse, M.; West, R. G.; Wilson, P. A.

    2016-08-01

    We present the discovery of three new transiting giant planets, first detected with the WASP telescopes, and establish their planetary nature with follow up spectroscopy and ground-based photometric lightcurves. WASP-92 is an F7 star, with a moderately inflated planet orbiting with a period of 2.17 days, which has Rp = 1.461 ± 0.077RJ and Mp = 0.805 ± 0.068MJ. WASP-93b orbits its F4 host star every 2.73 days and has Rp = 1.597 ± 0.077RJ and Mp = 1.47 ± 0.029MJ. WASP-118b also has a hot host star (F6) and is moderately inflated, where Rp = 1.440 ± 0.036RJ and Mp = 0.514 ± 0.020MJ and the planet has an orbital period of 4.05 days. They are bright targets (V = 13.18, 10.97 and 11.07 respectively) ideal for further characterisation work, particularly WASP-118b, which is being observed by K2 as part of campaign 8. The WASP-93 system has sufficient angular momentum to be tidally migrating outwards if the system is near spin-orbit alignment, which is divergent from the tidal behaviour of the majority of hot Jupiters discovered.

  12. Precise radial velocities of giant stars. VI. A possible 2:1 resonant planet pair around the K giant star η Ceti

    NASA Astrophysics Data System (ADS)

    Trifonov, Trifon; Reffert, Sabine; Tan, Xianyu; Lee, Man Hoi; Quirrenbach, Andreas

    2014-08-01

    We report the discovery of a new planetary system around the K giant η Cet (HIP 5364, HD 6805, HR 334) based on 118 high-precision optical radial velocities taken at Lick Observatory since July 2000. Since October 2011 an additional nine near-infrared Doppler measurements have been taken using the ESO CRIRES spectrograph (VLT, UT1). The visible data set shows two clear periodicities. Although we cannot completely rule out that the shorter period is due to rotational modulation of stellar features, the infrared data show the same variations as in the optical, which strongly supports that the variations are caused by two planets. Assuming the mass of η Cet to be 1.7 M⊙, the best edge-on coplanar dynamical fit to the data is consistent with two massive planets (mb sini = 2.6 ± 0.2 MJup, mc sini = 3.3 ± 0.2 MJup), with periods of Pb = 407 ± 3 days and Pc = 740 ± 5 days and eccentricities of eb = 0.12 ± 0.05 and ec = 0.08 ± 0.04. These mass and period ratios suggest possible strong interactions between the planets, and a dynamical test is mandatory. We tested a wide variety of edge-on coplanar and inclined planetary configurations for stability, which agree with the derived radial velocities. We find that for a coplanar configuration there are several isolated stable solutions and two well defined stability regions. In certain orbital configurations with moderate eb eccentricity, the planets can be effectively trapped in an anti-aligned 2:1 mean motion resonance that stabilizes the system. A much larger non-resonant stable region exists in low-eccentricity parameter space, although it appears to be much farther from the best fit than the 2:1 resonant region. In all other cases, the system is categorized as unstable or chaotic. Another conclusion from the coplanar inclined dynamical test is that the planets can be at most a factor of ~1.4 more massive than their suggested minimum masses. Assuming yet higher inclinations, and thus larger planetary masses, leads

  13. A giant planet around a metal-poor star of extragalactic origin.

    PubMed

    Setiawan, Johny; Klement, Rainer J; Henning, Thomas; Rix, Hans-Walter; Rochau, Boyke; Rodmann, Jens; Schulze-Hartung, Tim

    2010-12-17

    Stars in their late stage of evolution, such as horizontal branch stars, are still largely unexplored for planets. We detected a planetary companion around HIP 13044, a very metal-poor star on the red horizontal branch, on the basis of radial velocity observations with a high-resolution spectrograph at the 2.2-meter Max-Planck Gesellschaft-European Southern Observatory telescope. The star's periodic radial velocity variation of P = 16.2 days caused by the planet can be distinguished from the periods of the stellar activity indicators. The minimum mass of the planet is 1.25 times the mass of Jupiter and its orbital semimajor axis is 0.116 astronomical units. Because HIP 13044 belongs to a group of stars that have been accreted from a disrupted satellite galaxy of the Milky Way, the planet most likely has an extragalactic origin. PMID:21097905

  14. A giant planet around a metal-poor star of extragalactic origin.

    PubMed

    Setiawan, Johny; Klement, Rainer J; Henning, Thomas; Rix, Hans-Walter; Rochau, Boyke; Rodmann, Jens; Schulze-Hartung, Tim

    2010-12-17

    Stars in their late stage of evolution, such as horizontal branch stars, are still largely unexplored for planets. We detected a planetary companion around HIP 13044, a very metal-poor star on the red horizontal branch, on the basis of radial velocity observations with a high-resolution spectrograph at the 2.2-meter Max-Planck Gesellschaft-European Southern Observatory telescope. The star's periodic radial velocity variation of P = 16.2 days caused by the planet can be distinguished from the periods of the stellar activity indicators. The minimum mass of the planet is 1.25 times the mass of Jupiter and its orbital semimajor axis is 0.116 astronomical units. Because HIP 13044 belongs to a group of stars that have been accreted from a disrupted satellite galaxy of the Milky Way, the planet most likely has an extragalactic origin.

  15. Simulating the Gas-Assisted Capture of Earth-sized Moons around Extrasolar Giant Planets

    NASA Astrophysics Data System (ADS)

    Williams, D. M.

    2003-05-01

    The number of Jupiter-sized planets on orbits that cross the habitable zones of Sun-like stars is now 42. Moons of these planets might have oceans of liquid water if they are big enough to form and maintain atmospheres, which they should be able to do if they are slightly larger than Mars [Williams D.W., Kasting, J.F., & Wade, R.A.1997. Nature 385,234]. Here we demonstrate using a modified symplectic orbital integrator that such planet-sized moons may be captured through a chance collision between a terrestrial planet and a young jovian planet enveloped in a circumplanetary disk. We find that permanent capture is best achieved when the approach vector is approximately co-planar with the disk and the minimum planet-impactor separation is < 10 planetary radii. For optimal conditions, a 0.1 Jupiter-mass disk can capture and circularize an Earth-mass impactor in under 100 years. The ultimate fate of such moons and the nebula are currently being examined through hydrodynamic simulation.

  16. Two New Long-period Giant Planets from the McDonald Observatory Planet Search and Two Stars with Long-period Radial Velocity Signals Related to Stellar Activity Cycles

    NASA Astrophysics Data System (ADS)

    Endl, Michael; Brugamyer, Erik J.; Cochran, William D.; MacQueen, Phillip J.; Robertson, Paul; Meschiari, Stefano; Ramirez, Ivan; Shetrone, Matthew; Gullikson, Kevin; Johnson, Marshall C.; Wittenmyer, Robert; Horner, Jonathan; Ciardi, David R.; Horch, Elliott; Simon, Attila E.; Howell, Steve B.; Everett, Mark; Caldwell, Caroline; Castanheira, Barbara G.

    2016-02-01

    We report the detection of two new long-period giant planets orbiting the stars HD 95872 and HD 162004 ({\\psi }1 Dra B) by the McDonald Observatory planet search. The planet HD 95872b has a minimum mass of 4.6 {M}{{Jup}} and an orbital semimajor axis of 5.2 AU. The giant planet {\\psi }1 Dra Bb has a minimum mass of 1.5 {M}{{Jup}} and an orbital semimajor axis of 4.4 AU. Both of these planets qualify as Jupiter analogs. These results are based on over one and a half decades of precise radial velocity (RV) measurements collected by our program using the McDonald Observatory Tull Coude spectrograph at the 2.7 m Harlan J. Smith Telescope. In the case of {\\psi }1 Dra B we also detect a long-term nonlinear trend in our data that indicates the presence of an additional giant planet, similar to the Jupiter-Saturn pair. The primary of the binary star system, {\\psi }1 Dra A, exhibits a very large amplitude RV variation due to another stellar companion. We detect this additional member using speckle imaging. We also report two cases—HD 10086 and HD 102870 (β Virginis)—of significant RV variation consistent with the presence of a planet, but that are probably caused by stellar activity, rather than reflexive Keplerian motion. These two cases stress the importance of monitoring the magnetic activity level of a target star, as long-term activity cycles can mimic the presence of a Jupiter-analog planet.

  17. N-BODY SIMULATIONS OF SATELLITE FORMATION AROUND GIANT PLANETS: ORIGIN OF ORBITAL CONFIGURATION OF THE GALILEAN MOONS

    SciTech Connect

    Ogihara, Masahiro; Ida, Shigeru E-mail: ida@geo.titech.ac.jp

    2012-07-01

    As the number of discovered extrasolar planets has been increasing, diversity of planetary systems requires studies of new formation scenarios. It is important to study satellite formation in circumplanetary disks, which is often viewed as analogous to formation of rocky planets in protoplanetary disks. We investigated satellite formation from satellitesimals around giant planets through N-body simulations that include gravitational interactions with a circumplanetary gas disk. Our main aim is to reproduce the observable properties of the Galilean satellites around Jupiter through numerical simulations, as previous N-body simulations have not explained the origin of the resonant configuration. We performed accretion simulations based on the work of Sasaki et al., in which an inner cavity is added to the model of Canup and Ward. We found that several satellites are formed and captured in mutual mean motion resonances outside the disk inner edge and are stable after rapid disk gas dissipation, which explains the characteristics of the Galilean satellites. In addition, owing to the existence of the disk edge, a radial compositional gradient of the Galilean satellites can also be reproduced. An additional objective of this study is to discuss orbital properties of formed satellites for a wide range of conditions by considering large uncertainties in model parameters. Through numerical experiments and semianalytical arguments, we determined that if the inner edge of a disk is introduced, a Galilean-like configuration in which several satellites are captured into a 2:1 resonance outside the disk inner cavity is almost universal. In fact, such a configuration is produced even for a massive disk {approx}> 10{sup 4} g cm{sup -2} and rapid type I migration. This result implies the inevitability of a Galilean satellite formation in addition to providing theoretical predictions for extrasolar satellites. That is, we can predict a substantial number of exomoon systems in the 2

  18. DISCOVERY AND ATMOSPHERIC CHARACTERIZATION OF GIANT PLANET KEPLER-12b: AN INFLATED RADIUS OUTLIER

    SciTech Connect

    Fortney, Jonathan J.; Nutzman, Philip; Demory, Brice-Olivier; Desert, Jean-Michel; Buchhave, Lars A.; Charbonneau, David; Fressin, Francois; Rowe, Jason; Caldwell, Douglas A.; Jenkins, Jon M.; Ciardi, David; Gautier, Thomas N.; Bryson, Stephen T.; Howell, Steve B.; Everett, Mark; and others

    2011-11-01

    We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 {+-} 0.030 R{sub J} is among the handful of planets with super-inflated radii above 1.65 R{sub J}. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 {+-} 0.041 M{sub J} planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 {+-} 0.010 g cm{sup -3}. We detect the occultation of the planet at a significance of 3.7{sigma} in the Kepler bandpass. This yields a geometric albedo of 0.14 {+-} 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7{sigma} and 4{sigma} in the 3.6 and 4.5 {mu}m bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1{sigma}) and e < 0.09 (3{sigma}). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets.

  19. The SOPHIE search for northern extrasolar planets. XI. Three new companions and an orbit update: Giant planets in the habitable zone

    NASA Astrophysics Data System (ADS)

    Díaz, R. F.; Rey, J.; Demangeon, O.; Hébrard, G.; Boisse, I.; Arnold, L.; Astudillo-Defru, N.; Beuzit, J.-L.; Bonfils, X.; Borgniet, S.; Bouchy, F.; Bourrier, V.; Courcol, B.; Deleuil, M.; Delfosse, X.; Ehrenreich, D.; Forveille, T.; Lagrange, A.-M.; Mayor, M.; Moutou, C.; Pepe, F.; Queloz, D.; Santerne, A.; Santos, N. C.; Sahlmann, J.; Ségransan, D.; Udry, S.; Wilson, P. A.

    2016-07-01

    We report the discovery of three new substellar companions to solar-type stars, HD 191806, HD 214823, and HD 221585, based on radial velocity measurements obtained at the Haute-Provence Observatory. Data from the SOPHIE spectrograph are combined with observations acquired with its predecessor, ELODIE, to detect and characterise the orbital parameters of three new gaseous giant and brown dwarf candidates. Additionally, we combine SOPHIE data with velocities obtained at the Lick Observatory to improve the parameters of an already known giant planet companion, HD 16175 b. Thanks to the use of different instruments, the data sets of all four targets span more than ten years. Zero-point offsets between instruments are dealt with using Bayesian priors to incorporate the information we possess on the SOPHIE/ELODIE offset based on previous studies. The reported companions have orbital periods between three and five years and minimum masses between 1.6 MJup and 19 MJup. Additionally, we find that the star HD 191806 is experiencing a secular acceleration of over 11 m s-1 per year, potentially due to an additional stellar or substellar companion. A search for the astrometric signature of these companions was carried out using Hipparcos data. No orbit was detected, but a significant upper limit to the companion mass can be set for HD 221585, whose companion must be substellar. With the exception of HD 191806 b, the companions are located within the habitable zone of their host star. Therefore, satellites orbiting these objects could be a propitious place for life to develop. Based on observations collected with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France by the SOPHIE Consortium (programme 07A.PNP.CONS to 15A.PNP.CONS).

  20. A NEW HYBRID N-BODY-COAGULATION CODE FOR THE FORMATION OF GAS GIANT PLANETS

    SciTech Connect

    Bromley, Benjamin C.; Kenyon, Scott J. E-mail: skenyon@cfa.harvard.edu

    2011-04-20

    We describe an updated version of our hybrid N-body-coagulation code for planet formation. In addition to the features of our 2006-2008 code, our treatment now includes algorithms for the one-dimensional evolution of the viscous disk, the accretion of small particles in planetary atmospheres, gas accretion onto massive cores, and the response of N-bodies to the gravitational potential of the gaseous disk and the swarm of planetesimals. To validate the N-body portion of the algorithm, we use a battery of tests in planetary dynamics. As a first application of the complete code, we consider the evolution of Pluto-mass planetesimals in a swarm of 0.1-1 cm pebbles. In a typical evolution time of 1-3 Myr, our calculations transform 0.01-0.1 M{sub sun} disks of gas and dust into planetary systems containing super-Earths, Saturns, and Jupiters. Low-mass planets form more often than massive planets; disks with smaller {alpha} form more massive planets than disks with larger {alpha}. For Jupiter-mass planets, masses of solid cores are 10-100 M{sub +}.

  1. Toward Direct Imaging of Low-mass Gas-Giant Planets with the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Schlieder, J. E.; Beichman, C. A.; Meyer, M. R.; Greene, T.

    2016-01-01

    In preparation for observations with the James Webb Space Telescope (JWST), we have identified new members of the nearby, young M dwarf sample and compiled an up to date list of these stars. Here we summarize our efforts to identify young M dwarfs, describe the current sample, and detail its demographics in the context of direct planet imaging. We also describe our investigations of the unprecedented sensitivity of the JWST when imaging nearby, young M dwarfs. The JWST is the only near term facility capable of routinely pushing direct imaging capabilities around M dwarfs to sub-Jovian masses and will provide key insight into questions regarding low-mass gas-giant properties, frequency, formation, and architectures.

  2. SECRETLY ECCENTRIC: THE GIANT PLANET AND ACTIVITY CYCLE OF GJ 328

    SciTech Connect

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Boss, Alan P.

    2013-09-10

    We announce the discovery of a {approx}2 Jupiter-mass planet in an eccentric 11 yr orbit around the K7/M0 dwarf GJ 328. Our result is based on 10 years of radial velocity (RV) data from the Hobby-Eberly and Harlan J. Smith telescopes at McDonald Observatory, and from the Keck Telescope at Mauna Kea. Our analysis of GJ 328's magnetic activity via the Na I D features reveals a long-period stellar activity cycle, which creates an additional signal in the star's RV curve with amplitude 6-10 m s{sup -1}. After correcting for this stellar RV contribution, we see that the orbit of the planet is more eccentric than suggested by the raw RV data. GJ 328b is currently the most massive, longest-period planet discovered around a low-mass dwarf.

  3. Formation of the Giant Planets by Concurrent Accretion of Solids and Gas

    NASA Technical Reports Server (NTRS)

    Hubickyj, Olenka

    1997-01-01

    Models were developed to simulate planet formation. Three major phases are characterized in the simulations: (1) planetesimal accretion rate, which dominates that of gas, rapidly increases owing to runaway accretion, then decreases as the planet's feeding zone is depleted; (2) occurs when both solid and gas accretion rates are small and nearly independent of time; and (3) starts when the solid and gas masses are about equal and is marked by runaway gas accretion. The models applicability to planets in our Solar System are judged using two basic "yardsticks". The results suggest that the solar nebula dissipated while Uranus and Neptune were in the second phase, during which, for a relatively long time, the masses of their gaseous envelopes were small but not negligible compared to the total masses. Background information, results and a published article are included in the report.

  4. Secretly Eccentric: The Giant Planet and Activity Cycle of GJ 328

    NASA Astrophysics Data System (ADS)

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Boss, Alan P.

    2013-09-01

    We announce the discovery of a ~2 Jupiter-mass planet in an eccentric 11 yr orbit around the K7/M0 dwarf GJ 328. Our result is based on 10 years of radial velocity (RV) data from the Hobby-Eberly and Harlan J. Smith telescopes at McDonald Observatory, and from the Keck Telescope at Mauna Kea. Our analysis of GJ 328's magnetic activity via the Na I D features reveals a long-period stellar activity cycle, which creates an additional signal in the star's RV curve with amplitude 6-10 m s-1. After correcting for this stellar RV contribution, we see that the orbit of the planet is more eccentric than suggested by the raw RV data. GJ 328b is currently the most massive, longest-period planet discovered around a low-mass dwarf.

  5. DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

    SciTech Connect

    Bodenheimer, Peter; Fortney, Jonathan J.; Saumon, Didier E-mail: gennaro.dangelo@nasa.gov E-mail: jfortney@ucolick.org

    2013-06-20

    Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M{sub Circled-Plus }, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M{sub Jup}). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M{sub 50}, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M{sub 50} fall in the range 11.6-13.6 M{sub Jup}, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M{sub 50}. For masses above M{sub 50}, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.

  6. The K2-ESPRINT Project V: A Short-period Giant Planet Orbiting a Subgiant Star*

    NASA Astrophysics Data System (ADS)

    Van Eylen, Vincent; Albrecht, Simon; Gandolfi, Davide; Dai, Fei; Winn, Joshua N.; Hirano, Teriyuki; Narita, Norio; Bruntt, Hans; Prieto-Arranz, Jorge; Béjar, Víctor J. S.; Nowak, Grzegorz; Lund, Mikkel N.; Palle, Enric; Ribas, Ignasi; Sanchis-Ojeda, Roberto; Yu, Liang; Arriagada, Pamela; Butler, R. Paul; Crane, Jeffrey D.; Handberg, Rasmus; Deeg, Hans; Jessen-Hansen, Jens; Johnson, John A.; Nespral, David; Rogers, Leslie; Ryu, Tsuguru; Shectman, Stephen; Shrotriya, Tushar; Slumstrup, Ditte; Takeda, Yoichi; Teske, Johanna; Thompson, Ian; Vanderburg, Andrew; Wittenmyer, Robert

    2016-11-01

    We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 (EPIC 206247743) is an evolved star with a spectroscopically derived stellar radius and mass of {3.88}-0.42+0.48 {R}ȯ and {1.53}-0.12+0.13 {M}ȯ , respectively, and a very close-in transiting planet, with a/{R}\\star =3.4. Radial velocity (RV) follow-up using the HARPS, FIES, and PFS instruments leads to a planetary mass of {50.3}-9.4+9.7 {M}\\oplus . In combination with a radius measurement of 8.3+/- 1.1 {R}\\oplus , this results in a mean planetary density of {0.50}-0.17+0.29 g cm‑3. We furthermore discover a long-term RV trend, which may be caused by a long-period planet or stellar companion. Because K2-39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and main-sequence stars. Future monitoring of the transits of this system may enable the detection of period decay and constrain the tidal dissipation rates of subgiant stars. Based on observations made with the NOT telescope under program ID. 50-022/51-503, 50-213(CAT), 52-201 (CAT), 52-108 (OPTICON), 51-211 (CAT), and ESOs 3.6 m telescope at the La Silla Paranal Observatory under program ID 095.C-0718(A).

  7. The Pan-Pacific Planet Search. IV. Two Super-Jupiters in a 3:5 Resonance Orbiting the Giant Star HD 33844

    NASA Astrophysics Data System (ADS)

    Wittenmyer, Robert A.; Johnson, John Asher; Butler, R. P.; Horner, Jonathan; Wang, Liang; Robertson, Paul; Jones, M. I.; Jenkins, J. S.; Brahm, R.; Tinney, C. G.; Mengel, M. W.; Clark, J.

    2016-02-01

    We report the discovery of two giant planets orbiting the K giant HD 33844 based on radial velocity data from three independent campaigns. The planets move on nearly circular orbits with semimajor axes {a}b\\=1.60+/- 0.02 AU and {a}c=2.24+/- 0.05 AU, and have minimum masses (m sin i) of {M}b=1.96+/- 0.12 {M}{{Jup}} and {M}c=1.76+/- 0.18 {M}{{Jup}}. Detailed N-body dynamical simulations show that the two planets have remained on stable orbits for more than 106 years for low eccentricities and are most likely trapped in a mutual 3:5 mean motion resonance.

  8. Baroclinic instability in the interiors of the giant planets: A cooling history of Uranus?

    NASA Technical Reports Server (NTRS)

    Holme, Richard; Ingersoll, Andrew P.

    1994-01-01

    We propose a quasigeostrophic, baroclinic model for heat transport within the interior of a stably stratified Jovian planet, based on motion in thin cylindrical annuli. Density decreases from the center outward and is zero at the surface of the planet. In the homogeneous case (no core), we find instability for the poles hotter than the equator, but not for the reverse. If the motion is bounded by an impenetrable core, instability occurs for both cases. Much of the behavior can be explained by analogy to conventional baroclinic instability theory. Motivated by our results, we explore a possible connection between the highly inclined rotation axis of Uranus and its anomalously low surface heat flux. We assume that the planets formed hot. Our conjecture is that heat was efficiently convected outwards by baroclinic instability in Uranus (with the poles hotter than the equator), but not in the other three Jovian planets. The surface temperature was higher for the stably stratified case (Uranus), leading to a higher rate of infrared emission and faster cooling. Therefore, we propose that Uranus lost its internal heat sooner than Neptune because baroclinic motions, permitted by its inclination to the sun, were able to extract its internal heat while the surface was still warm.

  9. The science case for an orbital mission to Uranus: Exploring the origins and evolution of ice giant planets

    NASA Astrophysics Data System (ADS)

    Arridge, C. S.; Achilleos, N.; Agarwal, J.; Agnor, C. B.; Ambrosi, R.; André, N.; Badman, S. V.; Baines, K.; Banfield, D.; Barthélémy, M.; Bisi, M. M.; Blum, J.; Bocanegra-Bahamon, T.; Bonfond, B.; Bracken, C.; Brandt, P.; Briand, C.; Briois, C.; Brooks, S.; Castillo-Rogez, J.; Cavalié, T.; Christophe, B.; Coates, A. J.; Collinson, G.; Cooper, J. F.; Costa-Sitja, M.; Courtin, R.; Daglis, I. A.; de Pater, I.; Desai, M.; Dirkx, D.; Dougherty, M. K.; Ebert, R. W.; Filacchione, G.; Fletcher, L. N.; Fortney, J.; Gerth, I.; Grassi, D.; Grodent, D.; Grün, E.; Gustin, J.; Hedman, M.; Helled, R.; Henri, P.; Hess, S.; Hillier, J. K.; Hofstadter, M. H.; Holme, R.; Horanyi, M.; Hospodarsky, G.; Hsu, S.; Irwin, P.; Jackman, C. M.; Karatekin, O.; Kempf, S.; Khalisi, E.; Konstantinidis, K.; Krüger, H.; Kurth, W. S.; Labrianidis, C.; Lainey, V.; Lamy, L. L.; Laneuville, M.; Lucchesi, D.; Luntzer, A.; MacArthur, J.; Maier, A.; Masters, A.; McKenna-Lawlor, S.; Melin, H.; Milillo, A.; Moragas-Klostermeyer, G.; Morschhauser, A.; Moses, J. I.; Mousis, O.; Nettelmann, N.; Neubauer, F. M.; Nordheim, T.; Noyelles, B.; Orton, G. S.; Owens, M.; Peron, R.; Plainaki, C.; Postberg, F.; Rambaux, N.; Retherford, K.; Reynaud, S.; Roussos, E.; Russell, C. T.; Rymer, A. M.; Sallantin, R.; Sánchez-Lavega, A.; Santolik, O.; Saur, J.; Sayanagi, K. M.; Schenk, P.; Schubert, J.; Sergis, N.; Sittler, E. C.; Smith, A.; Spahn, F.; Srama, R.; Stallard, T.; Sterken, V.; Sternovsky, Z.; Tiscareno, M.; Tobie, G.; Tosi, F.; Trieloff, M.; Turrini, D.; Turtle, E. P.; Vinatier, S.; Wilson, R.; Zarka, P.

    2014-12-01

    Giant planets helped to shape the conditions we see in the Solar System today and they account for more than 99% of the mass of the Sun's planetary system. They can be subdivided into the Ice Giants (Uranus and Neptune) and the Gas Giants (Jupiter and Saturn), which differ from each other in a number of fundamental ways. Uranus, in particular is the most challenging to our understanding of planetary formation and evolution, with its large obliquity, low self-luminosity, highly asymmetrical internal field, and puzzling internal structure. Uranus also has a rich planetary system consisting of a system of inner natural satellites and complex ring system, five major natural icy satellites, a system of irregular moons with varied dynamical histories, and a highly asymmetrical magnetosphere. Voyager 2 is the only spacecraft to have explored Uranus, with a flyby in 1986, and no mission is currently planned to this enigmatic system. However, a mission to the uranian system would open a new window on the origin and evolution of the Solar System and would provide crucial information on a wide variety of physicochemical processes in our Solar System. These have clear implications for understanding exoplanetary systems. In this paper we describe the science case for an orbital mission to Uranus with an atmospheric entry probe to sample the composition and atmospheric physics in Uranus' atmosphere. The characteristics of such an orbiter and a strawman scientific payload are described and we discuss the technical challenges for such a mission. This paper is based on a white paper submitted to the European Space Agency's call for science themes for its large-class mission programme in 2013.

  10. A three-dimensional model of moist convection for the giant planets II: Saturn's water and ammonia moist convective storms

    NASA Astrophysics Data System (ADS)

    Hueso, Ricardo; Sánchez-Lavega, Agustín

    2004-11-01

    Moist convective storms constitute a key aspect in the global energy budget of the atmospheres of the giant planets. Among them, Saturn is known to develop the largest scale convective storms in the Solar System, the Great White Spots (GWS) which occur rarely and have been detected once every 30 years approximately. On the average, Saturn seems to show much less convective storms than Jupiter with smaller size and reduced frequency and intensity. Here we present detailed simulations of the onset and development of storms at the Equator and mid-latitudes of Saturn. These are the regions where most of the recent convective activity of the planet has been observed. We use a 3D anelastic model with parameterized microphysics (Hueso and Sánchez-Lavega, 2001, Icarus 151, 257) studying the onset and evolution of water and ammonia moist convective storms up to sizes of a few hundred km. Water storms, while more difficult to initiate than in Jupiter, can be very energetic, arriving to the 150 mbar level and developing vertical velocities on the order of 150 m s -1. Ammonia storms develop easier but with a much smaller intensity unless very large abundances of ammonia (10 times solar) are present in Saturn's atmosphere. The Coriolis forces play a major role in the morphology and properties of water based storms.

  11. Kepler-539: A young extrasolar system with two giant planets on wide orbits and in gravitational interaction

    NASA Astrophysics Data System (ADS)

    Mancini, L.; Lillo-Box, J.; Southworth, J.; Borsato, L.; Gandolfi, D.; Ciceri, S.; Barrado, D.; Brahm, R.; Henning, Th.

    2016-05-01

    We confirm the planetary nature of Kepler-539 b (aka Kepler object of interest K00372.01), a giant transiting exoplanet orbiting a solar-analogue G2 V star. The mass of Kepler-539 b was accurately derived thanks to a series of precise radial velocity measurements obtained with the CAFE spectrograph mounted on the CAHA 2.2-m telescope. A simultaneous fit of the radial-velocity data and Kepler photometry revealed that Kepler-539 b is a dense Jupiter-like planet with a mass of Mp = 0.97 ± 0.29 MJup and a radius of Rp = 0.747 ± 0.018 RJup, making a complete circular revolution around its parent star in 125.6 days. The semi-major axis of the orbit is roughly 0.5 au, implying that the planet is at ≈0.45 au from the habitable zone. By analysing the mid-transit times of the 12 transit events of Kepler-539 b recorded by the Kepler spacecraft, we found a clear modulated transit time variation (TTV), which is attributable to the presence of a planet c in a wider orbit. The few timings available do not allow us to precisely estimate the properties of Kepler-539 c and our analysis suggests that it has a mass between 1.2 and 3.6 MJup, revolving on a very eccentric orbit (0.4 planet c is the probable cause of the TTV modulation of planet b. The analysis of the CAFE spectra revealed a relatively high photospheric lithium content, A(Li) = 2.48 ± 0.12 dex, which, together with both a gyrochronological and isochronal analysis, suggests that the parent star is relatively young. RV/BVS measurements are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A112

  12. Recent Variability Observations of Solar System Giant Planets: Fresh Context for Understanding Exoplanet and Brown Dwarf Weather

    NASA Astrophysics Data System (ADS)

    Marley, Mark S.; Kepler Giant Planet Variability Team, Spitzer Ice Giant Variability Team

    2016-10-01

    Over the past several years a number of of high cadence photometric observations of solar system giant planets have been acquired by various platforms. Such observations are of interest as they provide points of comparison to the already expansive set of brown dwarf variability observations and the small, but growing, set of exoplanet variability observations. By measuring how rapidly the integrated light from solar system giant planets can evolve, variability observations of substellar objects that are unlikely to ever be resolved can be placed in a fuller context. Examples of brown dwarf variability observations include extensive work from the ground (e.g., Radigan et al. 2014), Spitzer (e.g., Metchev et al. 2015), Kepler (Gizis et al. 2015), and HST (Yang et al. 2015). Variability has been measured on the planetary mass companion to the brown dwarf 2MASS 1207b (Zhou et al. 2016) and further searches are planned in thermal emission for the known directly imaged planets with ground based telescopes (Apai et al. 2016) and in reflected light with future space based telescopes. Recent solar system variability observations include Kepler monitoring of Neptune (Simon et al. 2016) and Uranus, Spitzer observations of Neptune (Stauffer et al. 2016), and Cassini observations of Jupiter (West et al. in prep). The Cassini observations are of particular interest as they measured the variability of Jupiter at a phase angle of ˜60○, comparable to the viewing geometry expected for space based direct imaging of cool extrasolar Jupiters in reflected light. These solar system analog observations capture many of the characteristics seen in brown dwarf variability, including large amplitudes and rapid light curve evolution on timescales as short as a few rotation periods. Simon et al. (2016) attribute such variations at Neptune to a combination of large scale, stable cloud structures along with smaller, more rapidly varying, cloud patches. The observed brown dwarf and exoplanet

  13. Recent Variability Observations of Solar System Giant Planets: Fresh Context for Understanding Exoplanet and Brown Dwarf Weather

    NASA Technical Reports Server (NTRS)

    Marley, Mark Scott

    2016-01-01

    Over the past several years a number of high cadence photometric observations of solar system giant planets have been acquired by various platforms. Such observations are of interest as they provide points of comparison to the already expansive set of brown dwarf variability observations and the small, but growing, set of exoplanet variability observations. By measuring how rapidly the integrated light from solar system giant planets can evolve, variability observations of substellar objects that are unlikely to ever be resolved can be placed in a fuller context. Examples of brown dwarf variability observations include extensive work from the ground (e.g., Radigen et al. 2014), Spitzer (e.g., Metchev et al. 2015), Kepler (Gizis et al. 2015), and HST (Yang et al. 2015).Variability has been measured on the planetary mass companion to the brown dwarf 2MASS 1207b (Zhou et al. 2016) and further searches are planned in thermal emission for the known directly imaged planets with ground based telescopes (Apai et al. 2016) and in reflected light with future space based telescopes. Recent solar system variability observations include Kepler monitoring of Neptune (Simon et al. 2016) and Uranus, Spitzer observations of Neptune (Stauffer et al. 2016), and Cassini observations of Jupiter (West et al. in prep). The Cassini observations are of particular interest as they measured the variability of Jupiter at a phase angle of approximately 60 deg, comparable to the viewing geometry expected for space based direct imaging of cool extrasolar Jupiters in reflected light. These solar system analog observations capture many of the characteristics seen in brown dwarf variability, including large amplitudes and rapid light curve evolution on timescales as short as a few rotation periods. Simon et al. (2016) attribute such variations at Neptune to a combination of large scale, stable cloud structures along with smaller, more rapidly varying, cloud patches. The observed brown dwarf and

  14. Advanced Ion Mass Spectrometer for Giant Planet Ionospheres, Magnetospheres and Moons

    NASA Astrophysics Data System (ADS)

    Sittler, EC; Cooper, JF; Paschalidis, N.; Jones, SL; Rodriguez, M.; Ali, A.; Coplan, MA; Chornay, DJ; Sturner; Bateman, FB; Andre, N.; Fedorov, A.; Wurz, P.

    2015-10-01

    The Advanced Ion Composition Spectrometer (AIMS) has been under development from various NASA sources (NASA LWSID, NASA ASTID, NASA Goddard IRADs) to measure elemental, isotopic, and simple molecular composition abundances of 1 eV/e to 25 keV/e hot ions with wide field-of-view (FOV) in the 1 - 60 amu mass range at mass resolution M/ΔM ≤ 60 over a wide dynamic range of intensities and penetrating radiation background from the inner magnetospheres of Jupiter and Saturn to the outer magnetospheric boundary regions and the upstream solar wind. This instrument will work for both spinning spacecraft and 3-axis stabilized spacecraft with wide field-of-view capability in both cases. It will measure the ion velocity distribution functions (IVDF) for the individual ion species; ion velocity moments of the IVDF will give the fluid parameters (density, flow velocity and temperature) of the individual ion species. Outer planet mission applications are Io Observer, Jupiter Europa Orbiter/Europa Clipper, Enceladus Orbiter, and Uranus Orbiter as described in the decadal survey, but would also be valuable for inclusion on other missions to outer planet destinations such as Saturn- Titan and Neptune-Triton and for future missions to terrestrial planets, Venus and Mars, the Moon, asteroids, and comets, and of course for geospace applications to the Earth.

  15. Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system

    NASA Astrophysics Data System (ADS)

    Tingley, B.; Parviainen, H.; Gandolfi, D.; Deeg, H. J.; Palle, E.; Montañés Rodriguez, P.; Murgas, F.; Alonso, R.; Bruntt, H.; Fridlund, M.

    2014-07-01

    Aims: We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. Methods: We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. Results: We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1 MJup on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~30% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110 ± 0.0025, more than 25% more than the 0.087 measured by Kepler leading to a radius of 1.20 ± 0.16 RJup instead of the 0.94 RJup measured by the Kepler team. Conclusions: This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. While this technique is limited to candidates with deep transits from the ground, it may be possible to confirm earth-like exoplanet candidates with a few hours of observing time with an instrument like the James Webb Space Telescope. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors

  16. A statistical look at the retrieval of exoplanetary atmospheres of super Earths and giant planets

    NASA Astrophysics Data System (ADS)

    Rocchetto, Marco; Waldmann, Ingo Peter; Tinetti, Giovanna; Yurchenko, Sergey; Tennyson, Jonathan

    2015-08-01

    Over the past decades transit spectroscopy has become one of the pioneering methods to characterise exoplanetary atmospheres. With the increasing number of observations, and the advent of new ground and spaced based instruments, it is now crucial to find the most optimal and objective methodologies to interpret these data, and understand the information content they convey. This is particularly true for smaller and fainter super Earth type planets.In this conference we will present a new take on the spectral retrieval of transiting planets, with particular focus on super Earth atmospheres. TauREx (Waldmann et al. 2015a,b.) is a new line-by-line radiative transfer atmospheric retrieval framework for transmission and emission spectroscopy of exoplanetary atmospheres, optimised for hot Jupiters and super Earths. The code has been built from scratch with the ideas of scalability, flexibility and automation. This allows to run retrievals with minimum user input that can be scaled to large cluster computing. Priors on the number and types of molecules considered are automatically determined using a custom built pattern recognition algorithm able to identify the most likely absorbers/emitters in the exoplanetary spectra, minimising the human bias in selecting the major atmospheric constituents.Using these tools, we investigate the impact of signal to noise, spectral resolution and wavelength coverage on the retrievability of individual model parameters from transit spectra of super Earths, and put our models to test (Rocchetto et al. 2015). Characterisation of the atmospheres of super Earths through transit spectroscopy is paramount, as it can provide an indirect - and so far unique - way to probe the nature of these planets. For the first time we analyse in a systematic way large grids of spectra generated for different observing scenarios. We perform thousands of retrievals aimed to fully map the degeneracies and understand the statistics of current exoplanetary

  17. High Contrast Imaging with Spitzer: Constraining the Frequency of Giant Planets out to 1000 au Separations

    NASA Astrophysics Data System (ADS)

    Durkan, Stephen; Janson, Markus; Carson, Joseph C.

    2016-06-01

    We report results of a re-analysis of archival Spitzer IRAC direct imaging surveys encompassing a variety of nearby stars. Our sample is generated from the combined observations of 73 young stars (median age, distance, spectral type = 85 Myr, 23.3 pc, G5) and 48 known exoplanet host stars with unconstrained ages (median distance, spectral type = 22.6 pc, G5). While the small size of Spitzer provides a lower resolution than 8 m class AO-assisted ground-based telescopes, which have been used for constraining the frequency of 0.5–13 M J planets at separations of 10–102 au, its exquisite infrared sensitivity provides the ability to place unmatched constraints on the planetary populations at wider separations. Here we apply sophisticated high-contrast techniques to our sample in order to remove the stellar point-spread function and to open up sensitivity to planetary mass companions down to 5″ separations. This enables sensitivity to 0.5–13 M J planets at physical separations on the order of 102–103 au, allowing us to probe a parameter space that has not previously been systematically explored to any similar degree of sensitivity. Based on a color and proper motion analysis, we do not record any planetary detections. Exploiting this enhanced survey sensitivity, employing Monte Carlo simulations with a Bayesian approach, and assuming a mass distribution of {dn}/{dm}\\propto {m}-1.31, we constrain (at 95% confidence) a population of 0.5–13 M J planets at separations of 100–1000 au with an upper frequency limit of 9%.

  18. Discovery of a Gas Giant Planet in Microlensing Event OGLE-2014-BLG-1760

    NASA Astrophysics Data System (ADS)

    Bhattacharya, A.; Bennett, D. P.; Bond, I. A.; Sumi, T.; Udalski, A.; Street, R.; Tsapras, Y.; Abe, F.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Rattenbury, N.; Saito, T.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; MOA Collaboration; Skowron, J.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Mróz, P.; Kozlowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Wyrzykowski, L.; OGLE Collaboration; Bachelet, E.; Bramich, D. M.; D’Ago, G.; Dominik, M.; Figuera Jaimes, R.; Horne, K.; Hundertmark, M.; Kains, N.; Menzies, J.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Wambsganss, J.; ROBONET Collaboration

    2016-11-01

    We present the analysis of the planetary microlensing event OGLE-2014-BLG-1760, which shows a strong light-curve signal due to the presence of a Jupiter mass ratio planet. One unusual feature of this event is that the source star is quite blue, with V-I=1.48+/- 0.08. This is marginally consistent with a source star in the Galactic bulge, but it could possibly indicate a young source star on the far side of the disk. Assuming a bulge source, we perform a Bayesian analysis assuming a standard Galactic model, and this indicates that the planetary system resides in or near the Galactic bulge at {D}L=6.9+/- 1.1 {kpc}. It also indicates a host-star mass of {M}* ={0.51}-0.28+0.44{M}ȯ , a planet mass of {m}{{p}}={0.56}-0.26+0.34{M}J, and a projected star–planet separation of {a}\\perp ={1.75}-0.33+0.34 au. The lens–source relative proper motion is {μ }{rel}=6.5+/- 1.1 mas yr‑1. The lens (and stellar host star) is estimated to be very faint compared to the source star, so it is most likely that it can be detected only when the lens and source stars start to separate. Due to the relatively high relative proper motion, the lens and source will be resolved to about ∼46 mas in 6–8 yr after the peak magnification. So, by 2020–2022, we can hope to detect the lens star with deep, high-resolution images.

  19. High Contrast Imaging with Spitzer: Constraining the Frequency of Giant Planets out to 1000 au Separations

    NASA Astrophysics Data System (ADS)

    Durkan, Stephen; Janson, Markus; Carson, Joseph C.

    2016-06-01

    We report results of a re-analysis of archival Spitzer IRAC direct imaging surveys encompassing a variety of nearby stars. Our sample is generated from the combined observations of 73 young stars (median age, distance, spectral type = 85 Myr, 23.3 pc, G5) and 48 known exoplanet host stars with unconstrained ages (median distance, spectral type = 22.6 pc, G5). While the small size of Spitzer provides a lower resolution than 8 m class AO-assisted ground-based telescopes, which have been used for constraining the frequency of 0.5-13 M J planets at separations of 10-102 au, its exquisite infrared sensitivity provides the ability to place unmatched constraints on the planetary populations at wider separations. Here we apply sophisticated high-contrast techniques to our sample in order to remove the stellar point-spread function and to open up sensitivity to planetary mass companions down to 5″ separations. This enables sensitivity to 0.5-13 M J planets at physical separations on the order of 102-103 au, allowing us to probe a parameter space that has not previously been systematically explored to any similar degree of sensitivity. Based on a color and proper motion analysis, we do not record any planetary detections. Exploiting this enhanced survey sensitivity, employing Monte Carlo simulations with a Bayesian approach, and assuming a mass distribution of {dn}/{dm}\\propto {m}-1.31, we constrain (at 95% confidence) a population of 0.5-13 M J planets at separations of 100-1000 au with an upper frequency limit of 9%.

  20. Dissociation of CH4 at high pressures and temperatures: diamond formation in giant planet interiors?

    PubMed

    Benedetti, L R; Nguyen, J H; Caldwell, W A; Liu, H; Kruger, M; Jeanloz, R

    1999-10-01

    Experiments using laser-heated diamond anvil cells show that methane (CH4) breaks down to form diamond at pressures between 10 and 50 gigapascals and temperatures of about 2000 to 3000 kelvin. Infrared absorption and Raman spectroscopy, along with x-ray diffraction, indicate the presence of polymeric hydrocarbons in addition to the diamond, which is in agreement with theoretical predictions. Dissociation of CH4 at high pressures and temperatures can influence the energy budgets of planets containing substantial amounts of CH4, water, and ammonia, such as Uranus and Neptune. PMID:10506552

  1. Dissociation of CH4 at high pressures and temperatures: diamond formation in giant planet interiors?

    PubMed

    Benedetti, L R; Nguyen, J H; Caldwell, W A; Liu, H; Kruger, M; Jeanloz, R

    1999-10-01

    Experiments using laser-heated diamond anvil cells show that methane (CH4) breaks down to form diamond at pressures between 10 and 50 gigapascals and temperatures of about 2000 to 3000 kelvin. Infrared absorption and Raman spectroscopy, along with x-ray diffraction, indicate the presence of polymeric hydrocarbons in addition to the diamond, which is in agreement with theoretical predictions. Dissociation of CH4 at high pressures and temperatures can influence the energy budgets of planets containing substantial amounts of CH4, water, and ammonia, such as Uranus and Neptune.

  2. A Gas-Poor Planetesimal Feeding Model for the Formation of Giant Planet Satellite Systems: Consequences for the Atmosphere of Titan

    NASA Technical Reports Server (NTRS)

    Estrada, P. R.; Mosqueira, I.

    2005-01-01

    Given our presently inadequate understanding of the turbulent state of the solar and planetary nebulae, we believe the way to make progress in satellite formation is to consider two end member models that avoid over-reliance on specific choices of the turbulence (alpha), which is essentially a free parameter. The first end member model postulates turbulence decay once giant planet accretion ends. If so, Keplerian disks must eventually pass through the quiescent phases, so that the survival of satellites (and planets) ultimately hinges on gap-opening. In this scenario, the criterion for gap-opening itself sets the value for the gas surface density of the satellite disk.

  3. The mass of the planet-hosting giant star β Geminorum determined from its p-mode oscillation spectrum

    NASA Astrophysics Data System (ADS)

    Hatzes, A. P.; Zechmeister, M.; Matthews, J.; Kuschnig, R.; Walker, G. A. H.; Döllinger, M.; Guenther, D. B.; Moffat, A. F. J.; Rucinski, S. M.; Sasselov, D.; Weiss, W. W.

    2012-07-01

    Aims: Our aim is to use precise radial velocity measurements and photometric data to derive the frequency spacing of the p-mode oscillation spectrum of the planet-hosting star β Gem. This spacing along with the interferometric radius for this star can then be used to derive an accurate stellar mass. Methods: We use a long time series of over 60 h of precise stellar radial velocity measurements of β Gem taken with an iodine absorption cell at the echelle spectrograph mounted on the 2 m Alfred Jensch Telescope. We also present complementary photometric data for this star taken with the MOST microsatellite spanning 3.6 d. A Fourier analysis is used to derive the frequencies that are present in each data set. Results: The Fourier analysis of the radial velocity data reveals the presence of up to 17 significant pulsation modes in the frequency interval 10-250 μHz. Most of these fall on a grid of equally-spaced frequencies having a separation of 7.14 ± 0.12 μHz. An analysis of 3.6 days of high precision photometry taken with the MOST space telescopes shows the presence of up to 16 modes, six of which are consistent with modes found in the spectral (radial velocity) data. This frequency spacing is consistent with high overtone radial pulsations; however, until the pulsation modes are identified we cannot be sure if some of these are nonradial modes or even mixed modes. The radial velocity frequency spacing along with angular diameter measurements of β Gem via interferometry results in a stellar mass of M = 1.91 ± 0.09 M⊙. This value confirms the intermediate mass of the star determined using stellar evolutionary tracks. Conclusions.β Gem is confirmed to be an intermediate mass star. Stellar pulsations in giant stars along with interferometric radius measurements can provide accurate determinations of the stellar mass of planet hosting giant stars. These can also be used to calibrate stellar evolutionary tracks. Based on observations obtained at the 2 m Alfred

  4. Orbital Phase Variations of the Eccentric Giant Planet HAT-P-2b

    NASA Astrophysics Data System (ADS)

    Lewis, Nikole K.; Knutson, Heather A.; Showman, Adam P.; Cowan, Nicolas B.; Laughlin, Gregory; Burrows, Adam; Deming, Drake; Crepp, Justin R.; Mighell, Kenneth J.; Agol, Eric; Bakos, Gáspár Á.; Charbonneau, David; Désert, Jean-Michel; Fischer, Debra A.; Fortney, Jonathan J.; Hartman, Joel D.; Hinkley, Sasha; Howard, Andrew W.; Johnson, John Asher; Kao, Melodie; Langton, Jonathan; Marcy, Geoffrey W.

    2013-04-01

    We present the first secondary eclipse and phase curve observations for the highly eccentric hot Jupiter HAT-P-2b in the 3.6, 4.5, 5.8, and 8.0 μm bands of the Spitzer Space Telescope. The 3.6 and 4.5 μm data sets span an entire orbital period of HAT-P-2b (P = 5.6334729 d), making them the longest continuous phase curve observations obtained to date and the first full-orbit observations of a planet with an eccentricity exceeding 0.2. We present an improved non-parametric method for removing the intrapixel sensitivity variations in Spitzer data at 3.6 and 4.5 μm that robustly maps position-dependent flux variations. We find that the peak in planetary flux occurs at 4.39 ± 0.28, 5.84 ± 0.39, and 4.68 ± 0.37 hr after periapse passage with corresponding maxima in the planet/star flux ratio of 0.1138% ± 0.0089%, 0.1162% ± 0.0080%, and 0.1888% ± 0.0072% in the 3.6, 4.5, and 8.0 μm bands, respectively. Our measured secondary eclipse depths of 0.0996% ± 0.0072%, 0.1031% ± 0.0061%, 0.071%^{+0.029%}_{-0.013%}, and 0.1392% ± 0.0095% in the 3.6, 4.5, 5.8, and 8.0 μm bands, respectively, indicate that the planet cools significantly from its peak temperature before we measure the dayside flux during secondary eclipse. We compare our measured secondary eclipse depths to the predictions from a one-dimensional radiative transfer model, which suggests the possible presence of a transient day side inversion in HAT-P-2b's atmosphere near periapse. We also derive improved estimates for the system parameters, including its mass, radius, and orbital ephemeris. Our simultaneous fit to the transit, secondary eclipse, and radial velocity data allows us to determine the eccentricity (e = 0.50910 ± 0.00048) and argument of periapse (ω = 188.°09 ± 0.°39) of HAT-P-2b's orbit with a greater precision than has been achieved for any other eccentric extrasolar planet. We also find evidence for a long-term linear trend in the radial velocity data. This trend suggests the presence

  5. The effect of large-scale tropospheric storms on the ionospheres of giant planets

    NASA Astrophysics Data System (ADS)

    Matcheva, Katia

    2015-11-01

    It is well recognized that large-scale storms in the Earth troposphere can leave observable signatures in the structure of the ionosphere in terms of local electron density distribution. Terrestrial numerical models indicate that thunderstorms can change the electron density by more than an order of magnitude (Shao et al. 2012). The atmospheres of Jupiter and Saturn are riddled by atmospheric storms of all scales. Lightning has been successfully detected in optical images in the tropospheres of both planets. Our work presents a theoretical study of the dynamical and electromagnetic effects of large thunderstorms on the vertical plasma distribution in the ionospheres of Jupiter and Saturn and compares the predicted signatures with the available electron density profiles from the Galileo and the Cassini missions.

  6. ORBITAL PHASE VARIATIONS OF THE ECCENTRIC GIANT PLANET HAT-P-2b

    SciTech Connect

    Lewis, Nikole K.; Showman, Adam P.; Knutson, Heather A.; Desert, Jean-Michel; Kao, Melodie; Cowan, Nicolas B.; Laughlin, Gregory; Fortney, Jonathan J.; Burrows, Adam; Bakos, Gaspar A.; Hartman, Joel D.; Deming, Drake; Crepp, Justin R.; Mighell, Kenneth J.; Agol, Eric; Charbonneau, David; Fischer, Debra A.; Hinkley, Sasha; Johnson, John Asher; Howard, Andrew W.; and others

    2013-04-01

    We present the first secondary eclipse and phase curve observations for the highly eccentric hot Jupiter HAT-P-2b in the 3.6, 4.5, 5.8, and 8.0 {mu}m bands of the Spitzer Space Telescope. The 3.6 and 4.5 {mu}m data sets span an entire orbital period of HAT-P-2b (P = 5.6334729 d), making them the longest continuous phase curve observations obtained to date and the first full-orbit observations of a planet with an eccentricity exceeding 0.2. We present an improved non-parametric method for removing the intrapixel sensitivity variations in Spitzer data at 3.6 and 4.5 {mu}m that robustly maps position-dependent flux variations. We find that the peak in planetary flux occurs at 4.39 {+-} 0.28, 5.84 {+-} 0.39, and 4.68 {+-} 0.37 hr after periapse passage with corresponding maxima in the planet/star flux ratio of 0.1138% {+-} 0.0089%, 0.1162% {+-} 0.0080%, and 0.1888% {+-} 0.0072% in the 3.6, 4.5, and 8.0 {mu}m bands, respectively. Our measured secondary eclipse depths of 0.0996% {+-} 0.0072%, 0.1031% {+-} 0.0061%, 0.071%{sub -0.013%}{sup +0.029,} and 0.1392% {+-} 0.0095% in the 3.6, 4.5, 5.8, and 8.0 {mu}m bands, respectively, indicate that the planet cools significantly from its peak temperature before we measure the dayside flux during secondary eclipse. We compare our measured secondary eclipse depths to the predictions from a one-dimensional radiative transfer model, which suggests the possible presence of a transient day side inversion in HAT-P-2b's atmosphere near periapse. We also derive improved estimates for the system parameters, including its mass, radius, and orbital ephemeris. Our simultaneous fit to the transit, secondary eclipse, and radial velocity data allows us to determine the eccentricity (e = 0.50910 {+-} 0.00048) and argument of periapse ({omega} = 188. Degree-Sign 09 {+-} 0. Degree-Sign 39) of HAT-P-2b's orbit with a greater precision than has been achieved for any other eccentric extrasolar planet. We also find evidence for a long-term linear

  7. The need of Professional-Amateur collaborations to the monitoring of the giant planets

    NASA Astrophysics Data System (ADS)

    Kardasis, E.; Maravelias, G.; Yanamandra-Fisher, P.; Orton, G.; Rogers, J.; Jacquesson, M.; Christou A.; Delcroix M.

    2013-09-01

    The observation of gaseous planets is of high scientific interest. Although they have been the targets of several space missions, still the need for continuous ground-based observations remains. As their atmospheres present a fast dynamic environment the time availability in professional telescopes is not enough to follow them. On the other hand, numerous amateurs with small telescopes (with typical diameters of 15-60cm) and sufficient modern hardware and software equipment can monitor these changes daily (within the 360-900nm wavelength range). Their observations provide a continuous record and it is not uncommon to trigger professional observations in cases of extremely rare and important events. Amateur observations are able to trace the structure and the evolution of atmospheric features, such as major planetary scale disturbances, vortices, and storms. Photometric monitoring of stellar occultation’s by the planets can reveal spatial/temporal atmospheric variabilities. Moreover, 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 of the impactors. Thus, co-ordination and communication between professionals and amateurs is important. We present paradigms of such collaborations that: (i) engage systematic multiwavelength observations and databases, (ii) examine the variability of Jovian cloud features (JUPOSDatabase for Object Positions on Jupiter), (iii) provide, by ground-based professional and mainly amateur observations, the necessary spatial and temporal resolution of features that will be sampled by the space mission Juno, (iv) investigate video observations of Jupiter to recover impacts of small objects (Jovian Impacts Detection-JID and DeTeCtion of bolides in Jupiter atmosphere-DeTeCt software), (v) launch stellar occultation campaigns.

  8. AB INITIO EQUATION OF STATE FOR HYDROGEN-HELIUM MIXTURES WITH RECALIBRATION OF THE GIANT-PLANET MASS-RADIUS RELATION

    SciTech Connect

    Militzer, B.; Hubbard, W. B.

    2013-09-10

    Using density functional molecular dynamics simulations, we determine the equation of state (EOS) for hydrogen-helium mixtures spanning density-temperature conditions typical of giant-planet interiors, {approx}0.2-9 g cm{sup -3} and 1000-80,000 K for a typical helium mass fraction of 0.245. In addition to computing internal energy and pressure, we determine the entropy using an ab initio thermodynamic integration technique. A comprehensive EOS table with 391 density-temperature points is constructed and the results are presented in the form of a two-dimensional free energy fit for interpolation. Deviations between our ab initio EOS and the semi-analytical EOS model by Saumon and Chabrier are analyzed in detail, and we use the results for initial revision of the inferred thermal state of giant planets with known values for mass and radius. Changes are most pronounced for planets in the Jupiter mass range and below. We present a revision to the mass-radius relationship that makes the hottest exoplanets increase in radius by {approx}0.2 Jupiter radii at fixed entropy and for masses greater than {approx}0.5 Jupiter mass. This change is large enough to have possible implications for some discrepant ''inflated giant exoplanets''.

  9. Searching for gas giant planets on Solar system scales - a NACO/APP L'-band survey of A- and F-type main-sequence stars

    NASA Astrophysics Data System (ADS)

    Meshkat, T.; Kenworthy, M. A.; Reggiani, M.; Quanz, S. P.; Mamajek, E. E.; Meyer, M. R.

    2015-11-01

    We report the results of a direct imaging survey of A- and F-type main-sequence stars searching for giant planets. A/F stars are often the targets of surveys, as they are thought to have more massive giant planets relative to solar-type stars. However, most imaging is only sensitive to orbital separations >30 au, where it has been demonstrated that giant planets are rare. In this survey, we take advantage of the high-contrast capabilities of the Apodizing Phase Plate coronagraph on NACO at the Very Large Telescope. Combined with optimized principal component analysis post-processing, we are sensitive to planetary-mass companions (2-12 MJup) at Solar system scales (≤30 au). We obtained data on 13 stars in the L' band and detected one new companion as part of this survey: an M6.0 ± 0.5 dwarf companion around HD 984. We re-detect low-mass companions around HD 12894 and HD 20385, both reported shortly after the completion of this survey. We use Monte Carlo simulations to determine new constraints on the low-mass (<80 MJup) companion frequency, as a function of mass and separation. Assuming solar-type planet mass and separation distributions, normalized to the planet frequency appropriate for A-stars, and the observed companion mass-ratio distribution for stellar companions extrapolated to planetary masses, we derive a truncation radius for the planetary mass companion surface density of <135 au at 95 per cent confidence.

  10. SPIRAL ARMS IN THE ASYMMETRICALLY ILLUMINATED DISK OF MWC 758 AND CONSTRAINTS ON GIANT PLANETS

    SciTech Connect

    Grady, C. A.; Muto, T.; Hashimoto, J.; Kwon, J.; Fukagawa, M.; Sai, S.; Currie, T.; Biller, B.; Thalmann, C.; Sitko, M. L.; Russell, R.; Wisniewski, J.; Dong, R.; Hornbeck, J.; Schneider, G.; Hines, D.; Martin, A. Moro; Feldt, M.; Henning, Th.; Pott, J.-U.; and others

    2013-01-01

    We present the first near-IR scattered light detection of the transitional disk associated with the Herbig Ae star MWC 758 using data obtained as part of the Strategic Exploration of Exoplanets and Disks with Subaru, and 1.1 {mu}m Hubble Space Telescope/NICMOS data. While submillimeter studies suggested there is a dust-depleted cavity with r = 0.''35, we find scattered light as close as 0.''1 (20-28 AU) from the star, with no visible cavity at H, K', or K{sub s} . We find two small-scaled spiral structures that asymmetrically shadow the outer disk. We model one of the spirals using spiral density wave theory, and derive a disk aspect ratio of h {approx} 0.18, indicating a dynamically warm disk. If the spiral pattern is excited by a perturber, we estimate its mass to be 5{sup +3} {sub -4} M{sub J} , in the range where planet filtration models predict accretion continuing onto the star. Using a combination of non-redundant aperture masking data at L' and angular differential imaging with Locally Optimized Combination of Images at K' and K{sub s} , we exclude stellar or massive brown dwarf companions within 300 mas of the Herbig Ae star, and all but planetary mass companions exterior to 0.''5. We reach 5{sigma} contrasts limiting companions to planetary masses, 3-4 M{sub J} at 1.''0 and 2 M{sub J} at 1.''55, using the COND models. Collectively, these data strengthen the case for MWC 758 already being a young planetary system.

  11. Spiral Arms in the Asymmetrically Illuminated Disk of MWC 758 and Constraints on Giant Planets

    NASA Astrophysics Data System (ADS)

    Grady, C. A.; Muto, T.; Hashimoto, J.; Fukagawa, M.; Currie, T.; Biller, B.; Thalmann, C.; Sitko, M. L.; Russell, R.; Wisniewski, J.; Dong, R.; Kwon, J.; Sai, S.; Hornbeck, J.; Schneider, G.; Hines, D.; Moro Martín, A.; Feldt, M.; Henning, Th.; Pott, J.-U.; Bonnefoy, M.; Bouwman, J.; Lacour, S.; Mueller, A.; Juhász, A.; Crida, A.; Chauvin, G.; Andrews, S.; Wilner, D.; Kraus, A.; Dahm, S.; Robitaille, T.; Jang-Condell, H.; Abe, L.; Akiyama, E.; Brandner, W.; Brandt, T.; Carson, J.; Egner, S.; Follette, K. B.; Goto, M.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Hodapp, K.; Ishii, M.; Iye, M.; Janson, M.; Kandori, R.; Knapp, G.; Kudo, T.; Kusakabe, N.; Kuzuhara, M.; Mayama, S.; McElwain, M.; Matsuo, T.; Miyama, S.; Morino, J.-I.; Nishimura, T.; Pyo, T.-S.; Serabyn, G.; Suto, H.; Suzuki, R.; Takami, M.; Takato, N.; Terada, H.; Tomono, D.; Turner, E.; Watanabe, M.; Yamada, T.; Takami, H.; Usuda, T.; Tamura, M.

    2013-01-01

    We present the first near-IR scattered light detection of the transitional disk associated with the Herbig Ae star MWC 758 using data obtained as part of the Strategic Exploration of Exoplanets and Disks with Subaru, and 1.1 μm Hubble Space Telescope/NICMOS data. While submillimeter studies suggested there is a dust-depleted cavity with r = 0.''35, we find scattered light as close as 0.''1 (20-28 AU) from the star, with no visible cavity at H, K', or Ks . We find two small-scaled spiral structures that asymmetrically shadow the outer disk. We model one of the spirals using spiral density wave theory, and derive a disk aspect ratio of h ~ 0.18, indicating a dynamically warm disk. If the spiral pattern is excited by a perturber, we estimate its mass to be 5+3 - 4 MJ , in the range where planet filtration models predict accretion continuing onto the star. Using a combination of non-redundant aperture masking data at L' and angular differential imaging with Locally Optimized Combination of Images at K' and Ks , we exclude stellar or massive brown dwarf companions within 300 mas of the Herbig Ae star, and all but planetary mass companions exterior to 0.''5. We reach 5σ contrasts limiting companions to planetary masses, 3-4 MJ at 1.''0 and 2 MJ at 1.''55, using the COND models. Collectively, these data strengthen the case for MWC 758 already being a young planetary system.

  12. The Transport of Plasma and Magnetic Flux in Giant Planet Magnetospheres

    NASA Astrophysics Data System (ADS)

    Russell, C. T.

    2013-05-01

    Both Jupiter and Saturn have moons that add significant quantities of neutrals and/or dust beyond geosynchronous orbit. This material becomes charged and interacts with the planetary plasma that is "orbiting" the planets at near corotational speeds, driven by the planetary ionospheres. Since this speed is greater than the keplerian orbital speed at these distances, the net force on the newly added charged mass is outward. The charged material is held in place by the magnetic field which stretches to the amount needed to balance centripetal and centrifugal forces. The currents involved in this process close in the ionosphere which is an imperfect conductor and the feet of the field lines hence slip poleward and the material near the equator moves outward. This motion allows the magnetosphere to divest itself of the added mass by transferring it to the magnetotail. The magnetotail in turn can rid itself of the newly added mass by the process of reconnection, interior to the region of added mass, freeing an island of magnetized plasma which then moves down the magnetotail no longer connected to the magnetosphere. This maintains a quasi-stationary conservation of mass in the magnetosphere with roughly constant mass and "periodic" disturbances. However, there is one other steady state the magnetosphere needs to maintain. It needs to replace the mass loaded flux tubes with emptied flux tubes. Thus the "emptied" flux tubes in the tail must move inward against the outgoing mass-loaded flux tubes. That they are buoyant is a help in this regard but it appears also to be helpful if the returning flux separates into thin flux tubes, just like air bubbles rising in a container with a leak in the bottom. In this way the magnetospheres of Jupiter and Saturn maintain their dynamic, steady-state convection patterns.

  13. Spiral Arms in the Asymmetrically Illuminated Disk of MWC 758 and Constraints on Giant Planets

    NASA Technical Reports Server (NTRS)

    Grady, C. A.; Muto, T.; Hashimoto, J.; Fukagawa, M.; Currie, T.; Biller, B.; Thalmann, C.; Sitko, M. L.; Russell, R.; Wisniewski, J.; Dong, R.; Kwon, J.; Sai, S.; Hornbeck, J.; Schneider, G.; Hines, D.; Moro Martin, A.; Feldt, M.; Henning, Th.; Pott, J.-U.; Bonnefoy, M.; Bouwman, J.; Lacour, S.; McElwain, M.; Serabyn, G.

    2013-01-01

    We present the first near-IR scattered light detection of the transitional disk associated with the Herbig Ae star MWC 758 using data obtained as part of the Strategic Exploration of Exoplanets and Disks with Subaru, and 1.1 micrometer Hubble Space Telescope/NICMOS data. While submillimeter studies suggested there is a dust-depleted cavity with r = 0".35, we find scattered light as close as 0".1 (20-28 AU) from the star, with no visible cavity at H, K', or Ks . We find two small-scaled spiral structures that asymmetrically shadow the outer disk. We model one of the spirals using spiral density wave theory, and derive a disk aspect ratio of h approximately 0.18, indicating a dynamically warm disk. If the spiral pattern is excited by a perturber, we estimate its mass to be 5(exp +3)(sub -4) M(sub J), in the range where planet filtration models predict accretion continuing onto the star. Using a combination of non-redundant aperture masking data at L' and angular differential imaging with Locally Optimized Combination of Images at K' and Ks , we exclude stellar or massive brown dwarf companions within 300 mas of the Herbig Ae star, and all but planetary mass companions exterior to 0".5. We reach 5 sigma contrasts limiting companions to planetary masses, 3-4 M(sub J) at 1".0 and 2 M(sub J) at 1".55, using the COND models. Collectively, these data strengthen the case for MWC 758 already being a young planetary system.

  14. Transiting exoplanets from the CoRoT space mission. XX. CoRoT-20b: A very high density, high eccentricity transiting giant planet

    NASA Astrophysics Data System (ADS)

    Deleuil, M.; Bonomo, A. S.; Ferraz-Mello, S.; Erikson, A.; Bouchy, F.; Havel, M.; Aigrain, S.; Almenara, J.-M.; Alonso, R.; Auvergne, M.; Baglin, A.; Barge, P.; Bordé, P.; Bruntt, H.; Cabrera, J.; Carpano, S.; Cavarroc, C.; Csizmadia, Sz.; Damiani, C.; Deeg, H. J.; Dvorak, R.; Fridlund, M.; Hébrard, G.; Gandolfi, D.; Gillon, M.; Guenther, E.; Guillot, T.; Hatzes, A.; Jorda, L.; Léger, A.; Lammer, H.; Mazeh, T.; Moutou, C.; Ollivier, M.; Ofir, A.; Parviainen, H.; Queloz, D.; Rauer, H.; Rodríguez, A.; Rouan, D.; Santerne, A.; Schneider, J.; Tal-Or, L.; Tingley, B.; Weingrill, J.; Wuchterl, G.

    2012-02-01

    We report the discovery by the CoRoT space mission of a new giant planet, CoRoT-20b. The planet has a mass of 4.24 ± 0.23 MJup and a radius of 0.84 ± 0.04 RJup. With a mean density of 8.87 ± 1.10 g cm-3, it is among the most compact planets known so far. Evolutionary models for the planet suggest a mass of heavy elements of the order of 800 M⊕ if embedded in a central core, requiring a revision either of the planet formation models or both planet evolution and structure models. We note however that smaller amounts of heavy elements are expected by more realistic models in which they are mixed throughout the envelope. The planet orbits a G-type star with an orbital period of 9.24 days and an eccentricity of 0.56.The star's projected rotational velocity is vsini = 4.5 ± 1.0 km s-1, corresponding to a spin period of 11.5 ± 3.1 days if its axis of rotation is perpendicular to the orbital plane. In the framework of Darwinian theories and neglecting stellar magnetic breaking, we calculate the tidal evolution of the system and show that CoRoT-20b is presently one of the very few Darwin-stable planets that is evolving toward a triple synchronous state with equality of the orbital, planetary and stellar spin periods. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany, and Spain.

  15. ON THE POSSIBILITY OF ENRICHMENT AND DIFFERENTIATION IN GAS GIANTS DURING BIRTH BY DISK INSTABILITY

    SciTech Connect

    Boley, Aaron C.; Durisen, Richard H.

    2010-11-20

    We investigate the coupling between rock-size solids and gas during the formation of gas giant planets by disk fragmentation in the outer regions of massive disks. In this study, we use three-dimensional radiative hydrodynamic simulations and model solids as a spatial distribution of particles. We assume that half of the total solid fraction is in small grains and half in large solids. The former are perfectly entrained with the gas and set the opacity in the disk, while the latter are allowed to respond to gas drag forces, with the back reaction on the gas taken into account. To explore the maximum effects of gas-solid interactions, we first consider 10 cm size particles. We then compare these results to a simulation with 1 km size particles, which explores the low-drag regime. We show that (1) disk instability planets have the potential to form large cores due to aerodynamic capturing of rock-size solids in spiral arms before fragmentation; (2) temporary clumps can concentrate tens of M{sub +} of solids in very localized regions before clump disruption; (3) the formation of permanent clumps, even in the outer disk, is dependent on the grain-size distribution, i.e., the opacity; (4) nonaxisymmetric structure in the disk can create disk regions that have a solids-to-gas ratio greater than unity; (5) the solid distribution may affect the fragmentation process; (6) proto-gas giants and proto-brown dwarfs can start as differentiated objects prior to the H{sub 2} collapse phase; (7) spiral arms in a gravitationally unstable disk are able to stop the inward drift of rock-size solids, even redistributing them to larger radii; and (8) large solids can form spiral arms that are offset from the gaseous spiral arms. We conclude that planet embryo formation can be strongly affected by the growth of solids during the earliest stages of disk accretion.

  16. Studies of Pressure-Broadening of Alkali Atom Resonance Lines for Modeling Atmospheres of Extrasolar Giant Planets and Brown Dwarfs

    NASA Technical Reports Server (NTRS)

    Kirby, Kate; Babb, J.; Yoshino, K.

    2004-01-01

    In L-dwarfs and T-dwarfs the resonance lines of sodium and potassium are so profoundly pressure-broadened that their wings extend several hundred nanometers from line center. With accurate knowledge of the line profiles as a function of temperature and pressure: such lines can prove to be valuable diagnostics of the atmospheres of such objects. We have initiated a joint program of theoretical and experimental research to study the line-broadening of alkali atom resonance lines due to collisions with species such as helium and molecular hydrogen. Although potassium and sodium are the alkali species of most interest in the atmospheres of cool brown dwarfs and extrasolar giant planets, some of our theoretical focus this year has involved the calculation of pressure-broadening of lithium resonance lines by He, as a test of a newly developed suite of computer codes. In addition, theoretical calculations have been carried out to determine the leading long range van der Waals coefficients for the interactions of ground and excited alkali metal atoms with helium atoms, to within a probable error of 2%. Such data is important in determining the behavior of the resonance line profiles in the far wings. Important progress has been made on the experimental aspects of the program since the arrival of a postdoctoral fellow in September. A new absorption cell has been designed, which incorporates a number of technical improvements over the previous cell, including a larger cell diameter to enhance the signal, and fittings which allow for easier cleaning, thereby significantly reducing the instrument down-time.

  17. Friends of hot Jupiters. I. A radial velocity search for massive, long-period companions to close-in gas giant planets

    SciTech Connect

    Knutson, Heather A.; Ngo, Henry; Johnson, John Asher; Fulton, Benjamin J.; Howard, Andrew W.; Montet, Benjamin T.; Kao, Melodie; Hinkley, Sasha; Morton, Timothy D.; Muirhead, Philip S.; Crepp, Justin R.; Bakos, Gaspar Á.; Batygin, Konstantin

    2014-04-20

    In this paper we search for distant massive companions to known transiting gas giant planets that may have influenced the dynamical evolution of these systems. We present new radial velocity observations for a sample of 51 planets obtained using the Keck HIRES instrument, and find statistically significant accelerations in fifteen systems. Six of these systems have no previously reported accelerations in the published literature: HAT-P-10, HAT-P-22, HAT-P-29, HAT-P-32, WASP-10, and XO-2. We combine our radial velocity fits with Keck NIRC2 adaptive optics (AO) imaging data to place constraints on the allowed masses and orbital periods of the companions responsible for the detected accelerations. The estimated masses of the companions range between 1-500 M {sub Jup}, with orbital semi-major axes typically between 1-75 AU. A significant majority of the companions detected by our survey are constrained to have minimum masses comparable to or larger than those of the transiting planets in these systems, making them candidates for influencing the orbital evolution of the inner gas giant. We estimate a total occurrence rate of 51% ± 10% for companions with masses between 1-13 M {sub Jup} and orbital semi-major axes between 1-20 AU in our sample. We find no statistically significant difference between the frequency of companions to transiting planets with misaligned or eccentric orbits and those with well-aligned, circular orbits. We combine our expanded sample of radial velocity measurements with constraints from transit and secondary eclipse observations to provide improved measurements of the physical and orbital characteristics of all of the planets included in our survey.

  18. Extrasolar planets

    PubMed Central

    Lissauer, Jack J.; Marcy, Geoffrey W.; Ida, Shigeru

    2000-01-01

    The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems. PMID:11035782

  19. Extrasolar planets.

    PubMed

    Lissauer, J J; Marcy, G W; Ida, S

    2000-11-01

    The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems.

  20. Extrasolar planets.

    PubMed

    Lissauer, J J; Marcy, G W; Ida, S

    2000-11-01

    The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems. PMID:11035782

  1. Friends of Hot Jupiters. IV. Stellar Companions Beyond 50 au Might Facilitate Giant Planet Formation, but Most are Unlikely to Cause Kozai-Lidov Migration

    NASA Astrophysics Data System (ADS)

    Ngo, Henry; Knutson, Heather A.; Hinkley, Sasha; Bryan, Marta; Crepp, Justin R.; Batygin, Konstantin; Crossfield, Ian; Hansen, Brad; Howard, Andrew W.; Johnson, John A.; Mawet, Dimitri; Morton, Timothy D.; Muirhead, Philip S.; Wang, Ji

    2016-08-01

    Stellar companions can influence the formation and evolution of planetary systems, but there are currently few observational constraints on the properties of planet-hosting binary star systems. We search for stellar companions around 77 transiting hot Jupiter systems to explore the statistical properties of this population of companions as compared to field stars of similar spectral type. After correcting for survey incompleteness, we find that 47 % +/- 7 % of hot Jupiter systems have stellar companions with semimajor axes between 50 and 2000 au. This is 2.9 times larger than the field star companion fraction in this separation range, with a significance of 4.4σ . In the 1-50 au range, only {3.9}-2.0+4.5 % of hot Jupiters host stellar companions, compared to the field star value of 16.4 % +/- 0.7 % , which is a 2.7σ difference. We find that the distribution of mass ratios for stellar companions to hot Jupiter systems peaks at small values and therefore differs from that of field star binaries which tend to be uniformly distributed across all mass ratios. We conclude that either wide separation stellar binaries are more favorable sites for gas giant planet formation at all separations, or that the presence of stellar companions preferentially causes the inward migration of gas giant planets that formed farther out in the disk via dynamical processes such as Kozai-Lidov oscillations. We determine that less than 20% of hot Jupiters have stellar companions capable of inducing Kozai-Lidov oscillations assuming initial semimajor axes between 1 and 5 au, implying that the enhanced companion occurrence is likely correlated with environments where gas giants can form efficiently.

  2. Friends of Hot Jupiters. IV. Stellar Companions Beyond 50 au Might Facilitate Giant Planet Formation, but Most are Unlikely to Cause Kozai–Lidov Migration

    NASA Astrophysics Data System (ADS)

    Ngo, Henry; Knutson, Heather A.; Hinkley, Sasha; Bryan, Marta; Crepp, Justin R.; Batygin, Konstantin; Crossfield, Ian; Hansen, Brad; Howard, Andrew W.; Johnson, John A.; Mawet, Dimitri; Morton, Timothy D.; Muirhead, Philip S.; Wang, Ji

    2016-08-01

    Stellar companions can influence the formation and evolution of planetary systems, but there are currently few observational constraints on the properties of planet-hosting binary star systems. We search for stellar companions around 77 transiting hot Jupiter systems to explore the statistical properties of this population of companions as compared to field stars of similar spectral type. After correcting for survey incompleteness, we find that 47 % +/- 7 % of hot Jupiter systems have stellar companions with semimajor axes between 50 and 2000 au. This is 2.9 times larger than the field star companion fraction in this separation range, with a significance of 4.4σ . In the 1–50 au range, only {3.9}-2.0+4.5 % of hot Jupiters host stellar companions, compared to the field star value of 16.4 % +/- 0.7 % , which is a 2.7σ difference. We find that the distribution of mass ratios for stellar companions to hot Jupiter systems peaks at small values and therefore differs from that of field star binaries which tend to be uniformly distributed across all mass ratios. We conclude that either wide separation stellar binaries are more favorable sites for gas giant planet formation at all separations, or that the presence of stellar companions preferentially causes the inward migration of gas giant planets that formed farther out in the disk via dynamical processes such as Kozai–Lidov oscillations. We determine that less than 20% of hot Jupiters have stellar companions capable of inducing Kozai–Lidov oscillations assuming initial semimajor axes between 1 and 5 au, implying that the enhanced companion occurrence is likely correlated with environments where gas giants can form efficiently.

  3. The mass of planet GJ 676A b from ground-based astrometry. A planetary system with two mature gas giants suitable for direct imaging

    NASA Astrophysics Data System (ADS)

    Sahlmann, J.; Lazorenko, P. F.; Ségransan, D.; Astudillo-Defru, N.; Bonfils, X.; Delfosse, X.; Forveille, T.; Hagelberg, J.; Lo Curto, G.; Pepe, F.; Queloz, D.; Udry, S.; Zimmerman, N. T.

    2016-11-01

    The star GJ 676A is an M0 dwarf hosting both gas-giant and super-Earth-type planets that were discovered with radial-velocity measurements. Using FORS2/VLT, we obtained position measurements of the star in the plane of the sky that tightly constrain its astrometric reflex motion caused by the super-Jupiter planet "b" in a 1052-day orbit. This allows us to determine the mass of this planet to be , which is 40% higher than the minimum mass inferred from the radial-velocity orbit. Using new HARPS radial-velocity measurements, we improve upon the orbital parameters of the inner low-mass planets "d" and "e" and we determine the orbital period of the outer giant planet "c" to be Pc = 7340 days under the assumption of a circular orbit. The preliminary minimum mass of planet "c" is Mcsini = 6.8 MJ with an upper limit of 39 MJ that we set using NACO/VLT high-contrast imaging. We also determine precise parallaxes and relative proper motions for both GJ 676A and its wide M3 companion GJ 676B. Although the system is probably quite mature, the masses and projected separations ( 0.̋1-0.̋4) of planets "b" and "c" make them promising targets for direct imaging with future instruments in space and on extremely large telescopes. In particular, we estimate that GJ 676A b and GJ 676A c are promising targets for directly detecting their reflected light with the WFIRST space mission. Our study demonstrates the synergy of radial-velocity and astrometric surveys that is necessary to identify the best targets for such a mission. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 385.C-0416 (A,B), 086.C-0515(A), 089.C-0115(D,E), 072.C-0488(E), 180.C-0886(A), 183.C-0437(A), 085.C-0019(A), 091.C-0034(A), 095.C-0551(A), 096.C-0460(A).Full Table A.2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/A77

  4. Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations

    NASA Astrophysics Data System (ADS)

    Nielsen, E. L.; Close, L. M.; Biller, B. A.; Masciadri, E.; Lenzen, R.

    2010-01-01

    We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast curves from Masciadri et al. (2005) and Biller et al. (2007), we consider what distributions of planet masses and semi-major axes can be ruled out by these data, based on Monte Carlo simulations of planet populations. We can set the following upper limit with 95% confidence: the fraction of stars with planets with semi-major axis between 20 and 100 AU, and mass above 4 MJup, is 20% or less. Also, with a distribution of planet mass of {dN}/{dM} ∝ M-1.16 in the range of 0.5-13 M Jup , we can rule out a power-law distribution for semi-major axis ({dN}/{da} ∝ aα) with index 0 and upper cut-off of 18 AU, and index -0.5 with an upper cut-off of 48 AU. For the distribution suggested by Cumming et al. (2008), a power-law of index -0.61, we can place an upper limit of 75 AU on the semi-major axis distribution.

  5. CROWDING-OUT OF GIANTS BY DWARFS: AN ORIGIN FOR THE LACK OF COMPANION PLANETS IN HOT JUPITER SYSTEMS

    SciTech Connect

    Ogihara, Masahiro; Inutsuka, Shu-ichiro; Kobayashi, Hiroshi

    2013-11-20

    We investigate the formation of close-in terrestrial planets from planetary embryos under the influence of a hot Jupiter (HJ) using gravitational N-body simulations that include gravitational interactions between the gas disk and the terrestrial planet (e.g., type I migration). Our simulations show that several terrestrial planets efficiently form outside the orbit of the HJ, making a chain of planets, and all of them gravitationally interact directly or indirectly with the HJ through resonance, which leads to inward migration of the HJ. We call this mechanism of induced migration of the HJ ''crowding-out''. The HJ is eventually lost through collision with the central star, and only several terrestrial planets remain. We also find that the efficiency of the crowding-out effect depends on the model parameters; for example, the heavier the disk is, the more efficient the crowding-out is. When planet formation occurs in a massive disk, the HJ can be lost to the central star and is never observed. On the other hand, for a less massive disk, the HJ and terrestrial planets can coexist; however, the companion planets may be below the detection limit of current observations. In both cases, systems with a HJ and terrestrial planets have little chance of detection. Therefore, our model naturally explains the lack of companion planets in HJ systems regardless of the disk mass. In effect, our model provides a theoretical prediction for future observations; additional planets can be discovered just outside the HJ, and their masses should generally be small.

  6. THERMAL-GRAVITATIONAL WIND EQUATION FOR THE WIND-INDUCED GRAVITATIONAL SIGNATURE OF GIANT GASEOUS PLANETS: MATHEMATICAL DERIVATION, NUMERICAL METHOD, AND ILLUSTRATIVE SOLUTIONS

    SciTech Connect

    Zhang, Keke; Kong, Dali; Schubert, Gerald E-mail: D.Kong@exeter.ac.uk

    2015-06-20

    The standard thermal wind equation (TWE) relating the vertical shear of a flow to the horizontal density gradient in an atmosphere has been used to calculate the external gravitational signature produced by zonal winds in the interiors of giant gaseous planets. We show, however, that in this application the TWE needs to be generalized to account for an associated gravitational perturbation. We refer to the generalized equation as the thermal-gravitational wind equation (TGWE). The generalized equation represents a two-dimensional kernel integral equation with the Green’s function in its integrand and is hence much more difficult to solve than the standard TWE. We develop an extended spectral method for solving the TGWE in spherical geometry. We then apply the method to a generic gaseous Jupiter-like object with idealized zonal winds. We demonstrate that solutions of the TGWE are substantially different from those of the standard TWE. We conclude that the TGWE must be used to estimate the gravitational signature of zonal winds in giant gaseous planets.

  7. Thermal-gravitational Wind Equation for the Wind-induced Gravitational Signature of Giant Gaseous Planets: Mathematical Derivation, Numerical Method, and Illustrative Solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Keke; Kong, Dali; Schubert, Gerald

    2015-06-01

    The standard thermal wind equation (TWE) relating the vertical shear of a flow to the horizontal density gradient in an atmosphere has been used to calculate the external gravitational signature produced by zonal winds in the interiors of giant gaseous planets. We show, however, that in this application the TWE needs to be generalized to account for an associated gravitational perturbation. We refer to the generalized equation as the thermal-gravitational wind equation (TGWE). The generalized equation represents a two-dimensional kernel integral equation with the Green’s function in its integrand and is hence much more difficult to solve than the standard TWE. We develop an extended spectral method for solving the TGWE in spherical geometry. We then apply the method to a generic gaseous Jupiter-like object with idealized zonal winds. We demonstrate that solutions of the TGWE are substantially different from those of the standard TWE. We conclude that the TGWE must be used to estimate the gravitational signature of zonal winds in giant gaseous planets.

  8. A GAS GIANT CIRCUMBINARY PLANET TRANSITING THE F STAR PRIMARY OF THE ECLIPSING BINARY STAR KIC 4862625 AND THE INDEPENDENT DISCOVERY AND CHARACTERIZATION OF THE TWO TRANSITING PLANETS IN THE KEPLER-47 SYSTEM

    SciTech Connect

    Kostov, V. B.; Tsvetanov, Z. I.; McCullough, P. R.; Valenti, J. A.; Hinse, T. C.; Hebrard, G.; Diaz, R. F.; Deleuil, M.

    2013-06-10

    We report the discovery of a transiting, gas giant circumbinary planet orbiting the eclipsing binary KIC 4862625 and describe our independent discovery of the two transiting planets orbiting Kepler-47. We describe a simple and semi-automated procedure for identifying individual transits in light curves and present our follow-up measurements of the two circumbinary systems. For the KIC 4862625 system, the 0.52 {+-} 0.018 R{sub Jupiter} radius planet revolves every {approx}138 days and occults the 1.47 {+-} 0.08 M{sub Sun }, 1.7 {+-} 0.06 R{sub Sun} F8 IV primary star producing aperiodic transits of variable durations commensurate with the configuration of the eclipsing binary star. Our best-fit model indicates the orbit has a semi-major axis of 0.64 AU and is slightly eccentric, e = 0.1. For the Kepler-47 system, we confirm the results of Orosz et al. Modulations in the radial velocity of KIC 4862625A are measured both spectroscopically and photometrically, i.e., via Doppler boosting, and produce similar results.

  9. On turbulence driven by axial precession and tidal evolution of the spin-orbit angle of close-in giant planets

    NASA Astrophysics Data System (ADS)

    Barker, Adrian J.

    2016-08-01

    The spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. This induces internal fluid motions inside the planet that are subject to a hydrodynamic instability. We study the turbulent damping of precessional fluid motions, as a result of this instability, in the simplest local computational model of a giant planet (or star), with and without a weak internal magnetic field. Our aim is to determine the outcome of this instability, and its importance in driving tidal evolution of the spin-orbit angle in precessing planets (and stars). We find that this instability produces turbulent dissipation that is sufficiently strong that it could drive significant tidal evolution of the spin-orbit angle for hot Jupiters with orbital periods shorter than about 10-18 d. If this mechanism acts in isolation, this evolution would be towards alignment or anti-alignment, depending on the initial angle, but the ultimate evolution (if other tidal mechanisms also contribute) is expected to be towards alignment. The turbulent dissipation is proportional to the cube of the precession frequency, so it leads to much slower damping of stellar spin-orbit angles, implying that this instability is unlikely to drive evolution of the spin-orbit angle in stars (either in planetary or close binary systems). We also find that the instability-driven flow can act as a system-scale dynamo, which may play a role in producing magnetic fields in short-period planets.

  10. Atmospheric Dynamics of Brown Dwarfs and Directly Imaged Giant Planets: Emergence of Zonal Jets and Eddies from Small-Scale Convective Perturbations

    NASA Astrophysics Data System (ADS)

    Showman, Adam P.; Zhang, Xi; Tan, Xianyu; Lewis, Nikole K.

    2014-11-01

    A variety of observations now provide evidence for vigorous motion in the atmospheres of brown dwarfs and directly imaged giant planets; these observations include spectral evidence for clouds, disequilibrium chemistry, lightcurve variability, and maps of surface patchiness. These observations raise major questions about the nature of the atmospheric circulation on these exotic worlds, which resemble high-heat-flux, high-gravity, rapidly rotating versions of Jupiter. Although brown dwarfs and directly imaged giant planets generally lack the strong external stellar irradiation that causes the atmospheric circulation on most solar system planets, the vigorous convection in their interiors will drive a wealth of waves and perhaps a coherent large-scale circulation in their overlying stably stratified atmospheres. Here, we investigate this process using state-of-the-art, global 3D simulations of the atmospheric circulation using the MITgcm. We parameterize convective perturbations near the radiative-convective boundary using a spatially and temporally random, isotropic, small-scale thermal forcing at the bottom of the domain. Radiation is parameterized with an idealized Newtonian cooling scheme. Clouds and condensates are neglected. Our simulations show that brown dwarfs can in many cases develop large-scale atmospheric circulations comprising banded flow patterns, zonal jets, turbulence, and in some cases stable vortices. We will describe how the amplitude, length scales, and fundamental nature of the circulation -- in particular, the tendency to favor zonal jets versus quasi-isotropic turbulence -- depends on the radiative time constant, the convective forcing amplitude and timescale, gravity, and other parameters. The simulations provide a foundation for understanding observed lightcurves and surface maps of brown dwarfs, and moreover illuminate the continuum of atmospheric-dynamics processes between brown dwarfs and Jupiter itself.

  11. The GAPS programme with HARPS-N at TNG. II. No giant planets around the metal-poor star HIP 11952

    NASA Astrophysics Data System (ADS)

    Desidera, S.; Sozzetti, A.; Bonomo, A. S.; Gratton, R.; Poretti, E.; Claudi, R.; Latham, D. W.; Affer, L.; Cosentino, R.; Damasso, M.; Esposito, M.; Giacobbe, P.; Malavolta, L.; Nascimbeni, V.; Piotto, G.; Rainer, M.; Scardia, M.; Schmid, V. S.; Lanza, A. F.; Micela, G.; Pagano, I.; Bedin, L. R.; Biazzo, K.; Borsa, F.; Carolo, E.; Covino, E.; Faedi, F.; Hébrard, G.; Lovis, C.; Maggio, A.; Mancini, L.; Marzari, F.; Messina, S.; Molinari, E.; Munari, U.; Pepe, F.; Santos, N.; Scandariato, G.; Shkolnik, E.; Southworth, J.

    2013-06-01

    In the context of the programme Global Architecture of Planetary Systems (GAPS), we have performed radial velocity monitoring of the metal-poor star HIP 11952 on 35 nights during about 150 days using the newly installed high-resolution spectrograph HARPS-N at the TNG and HARPS at the ESO 3.6 m telescope. The radial velocities show a scatter of 7 m s-1, compatible with the measurement errors for such a moderately warm metal-poor star (Teff = 6040 ± 120 K; [Fe/H] = -1.9 ± 0.1). We exclude the presence of the two giant planets with periods of 6.95 ± 0.01 d and 290.0 ± 16.2 d and radial velocity semi-amplitudes of 100.3 ± 19.4 m s-1 and 105.2 ± 14.7 m s-1, respectively, which have recently been announced. This result is important because HIP 11952 was thought to be the most metal-poor star hosting a planetary systemwith giant planets, which challenged some models of planet formation. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF at the Spanish Observatorio del Roque de los Muchachos of the IAC in the frame of the programme Global Architecture of Planetary Systems (GAPS). Based on observations collected at the La Silla Observatory, ESO (Chile): Program 185.D-0056.Table 1 is available in electronic form at http://www.aanda.org

  12. Planet Formation

    NASA Astrophysics Data System (ADS)

    Klahr, Hubert; Brandner, Wolfgang

    2011-02-01

    1. Historical notes on planet formation Bodenheimer; 2. The formation and evolution of planetary systems Bouwman et al.; 3. Destruction of protoplanetary disks by photoevaporation Richling, Hollenbach and Yorke; 4. Turbulence in protoplanetary accretion disks Klahr, Rozyczka, Dziourkevitch, Wunsch and Johansen; 5. The origin of solids in the early solar system Trieloff and Palme; 6. Experiments on planetesimal formation Wurm and Blum; 7. Dust coagulation in protoplanetary disks Henning, Dullemond, Wolf and Dominik; 8. The accretion of giant planet cores Thommes and Duncan; 9. Planetary transits: direct vision of extrasolar planets Lecavelier des Etangs and Vidal-Madjar; 10. The core accretion - gas capture model Hubickyj; 11. Properties of exoplanets Marcy, Fischer, Butler and Vogt; 12. Giant planet formation: theories meet observations Boss; 13. From hot Jupiters to hot Neptures … and below Lovis, Mayor and Udry; 14. Disk-planet interaction and migration Masset and Kley; 15. The Brown Dwarf - planet relation Bate; 16. From astronomy to astrobiology Brandner; 17. Overview and prospective Lin.

  13. Can there be additional rocky planets in the Habitable Zone of tight binary stars with a known gas giant?

    NASA Astrophysics Data System (ADS)

    Funk, B.; Pilat-Lohinger, E.; Eggl, S.

    2015-04-01

    Locating planets in Habitable Zones (HZs) around other stars is a growing field in contemporary astronomy. Since a large percentage of all G-M stars in the solar neighbourhood are expected to be part of binary or multiple stellar systems, investigations of whether habitable planets are likely to be discovered in such environments are of prime interest to the scientific community. As current exoplanet statistics predicts that the chances are higher to find new worlds in systems that are already known to have planets, we examine four known extrasolar planetary systems in tight binaries in order to determine their capacity to host additional habitable terrestrial planets. Those systems are Gliese 86, γ Cephei, HD 41004 and HD 196885. In the case of γ Cephei, our results suggest that only the M dwarf companion could host additional potentially habitable worlds. Neither could we identify stable, potentially habitable regions around HD 196885 A. HD 196885 B can be considered a slightly more promising target in the search for Earth-twins. Gliese 86 A turned out to be a very good candidate, assuming that the system's history has not been excessively violent. For HD 41004, we have identified admissible stable orbits for habitable planets, but those strongly depend on the parameters of the system. A more detailed investigation shows that for some initial conditions stable planetary motion is possible in the HZ of HD 41004 A. In spite of the massive companion HD 41004 Bb, we found that HD 41004 B, too, could host additional habitable worlds.

  14. Terrestrial planet and asteroid formation in the presence of giant planets. I. Relative velocities of planetesimals subject to Jupiter and Saturn perturbations.

    PubMed

    Kortenkamp, S J; Wetherill, G W

    2000-01-01

    We investigate the orbital evolution of 10(13)- to 10(25) -g planetesimals near 1 AU and in the asteroid belt (near 2.6 AU) prior to the stage of evolution when the mutual perturbations between the planetesimals become important. We include nebular gas drag and the effects of Jupiter and Saturn at their present masses and in their present orbits. Gas drag introduces a size-dependent phasing of the secular perturbations, which leads to a pronounced dip in encounter velocities (Venc) between bodies of similar mass. Plantesimals of identical mass have Venc approximately 1 and approximately 10 m s-1 (near 1 and 2.6 AU, respectively) while bodies differing by approximately 10 in mass have Venc approximately 10 and approximately 100 m s-1 (near 1 and 2.6 AU, respectively). Under these conditions, growth, rather than erosion, will occur only by collisions of bodies of nearly the same mass. There will be essentially no gravitational focusing between bodies less than 10(22) to 10(25) g, allowing growth of planetary embryos in the terrestrial planet region to proceed in a slower nonrunaway fashion. The environment in the asteroid belt will be even more forbidding and it is uncertain whether even the severely depleted present asteroid belt could form under these conditions. The perturbations of Jupiter and Saturn are quite sensitive to their semi-major axes and decrease when the planets' heliocentric distances are increased to allow for protoplanet migration. It is possible, though not clearly demonstrated, that this could produce a depleted asteroid belt but permit formation of a system of terrestrial planet embryos on a approximately 10(6)-year timescale, initially by nonrunaway growth and transitioning to runaway growth after approximately 10(5) years. The calculations reported here are valid under the condition that the relative velocities of the bodies are determined only by Jupiter and Saturn perturbations and by gas drag, with no mutual perturbations between

  15. Terrestrial planet and asteroid formation in the presence of giant planets. I. Relative velocities of planetesimals subject to Jupiter and Saturn perturbations

    NASA Technical Reports Server (NTRS)

    Kortenkamp, S. J.; Wetherill, G. W.

    2000-01-01

    We investigate the orbital evolution of 10(13)- to 10(25) -g planetesimals near 1 AU and in the asteroid belt (near 2.6 AU) prior to the stage of evolution when the mutual perturbations between the planetesimals become important. We include nebular gas drag and the effects of Jupiter and Saturn at their present masses and in their present orbits. Gas drag introduces a size-dependent phasing of the secular perturbations, which leads to a pronounced dip in encounter velocities (Venc) between bodies of similar mass. Plantesimals of identical mass have Venc approximately 1 and approximately 10 m s-1 (near 1 and 2.6 AU, respectively) while bodies differing by approximately 10 in mass have Venc approximately 10 and approximately 100 m s-1 (near 1 and 2.6 AU, respectively). Under these conditions, growth, rather than erosion, will occur only by collisions of bodies of nearly the same mass. There will be essentially no gravitational focusing between bodies less than 10(22) to 10(25) g, allowing growth of planetary embryos in the terrestrial planet region to proceed in a slower nonrunaway fashion. The environment in the asteroid belt will be even more forbidding and it is uncertain whether even the severely depleted present asteroid belt could form under these conditions. The perturbations of Jupiter and Saturn are quite sensitive to their semi-major axes and decrease when the planets' heliocentric distances are increased to allow for protoplanet migration. It is possible, though not clearly demonstrated, that this could produce a depleted asteroid belt but permit formation of a system of terrestrial planet embryos on a approximately 10(6)-year timescale, initially by nonrunaway growth and transitioning to runaway growth after approximately 10(5) years. The calculations reported here are valid under the condition that the relative velocities of the bodies are determined only by Jupiter and Saturn perturbations and by gas drag, with no mutual perturbations between

  16. ON THE ORBITAL EVOLUTION OF A GIANT PLANET PAIR EMBEDDED IN A GASEOUS DISK. II. A SATURN-JUPITER CONFIGURATION

    SciTech Connect

    Zhang Hui; Zhou Jilin

    2010-08-10

    We carry out a series of high-resolution (1024 x 1024) hydrodynamic simulations to investigate the orbital evolution of a Saturn-Jupiter pair embedded in a gaseous disk. This work extends the results of our previous work by exploring a different orbital configuration-Jupiter lies outside Saturn (q < 1, where q {identical_to} M{sub i} /M{sub o} is the mass ratio of the inner planet and the outer one). We focus on the effects of different initial separations (d) between the two planets and the various surface density profiles of the disk, where {sigma} {proportional_to} r {sup -}{alpha}. We also compare the results of different orbital configurations of the planet pair. Our results show that (1) when the initial separation is relatively large (d>d {sub iLr}, where d {sub iLr} is the distance between Jupiter and its first inner Lindblad resonance), the two planets undergo divergent migration. However, the inward migration of Saturn could be halted when Jupiter compresses the inner disk in which Saturn is embedded. (2) Convergent migration occurs when the initial separation is smaller (d < d {sub iLr}) and the density slope of the disk is nearly flat ({alpha} < 1/2). Saturn is then forced by Jupiter to migrate inward where the two planets are trapped into mean motion resonances (MMRs), and Saturn may get very close to the central star. (3) In the case of q < 1, the eccentricity of Saturn could be excited to a very high value (e{sub S} {approx} 0.4-0.5) by the MMRs and the system could maintain stability. These results explain the formation of MMRs in the exoplanet systems where the outer planet is more massive than the inner one. It also helps us to understand the origin of the 'hot Jupiter/Saturn' with a highly eccentric orbit.

  17. Reflected Light from Giant Planets in Habitable Zones: Tapping into the Power of the Cross-Correlation Function

    NASA Astrophysics Data System (ADS)

    Martins, J. H. C.; Santos, N. C.; Figueira, P.; Melo, C.

    2016-03-01

    The direct detection of reflected light from exoplanets is an excellent probe for the characterization of their atmospheres. The greatest challenge for this task is the low planet-to-star flux ratio, which even in the most favourable case is of the order of 10-4 in the optical. This ratio decreases even more for planets in their host's habitable zone, typically lower than 10-7. To reach the signal-to-noise level required for such detections, we propose to unleash the power of the Cross Correlation Function in combination with the collecting power of next generation observing facilities. The technique we propose has already yielded positive results by detecting the reflected spectral signature of 51 Pegasi b (see Martins et al. 2015). In this work, we attempted to infer the number of hours required for the detection of several planets in their host's habitable zone using the aforementioned technique from theoretical EELT observations. Our results show that for 5 of the selected planets it should be possible to directly recover their reflected spectral signature.

  18. Planetary Accretion in the Inner Solar System: Dependence on Nebula Surface Density Profile and Giant Planet Eccentricities

    NASA Technical Reports Server (NTRS)

    Chambers, J. E.; Cassen, P.

    2002-01-01

    We present 32 N-body simulations of planetary accretion in the inner Solar System, examining the effect of nebula surface density profile and initial eccentricities of Jupiter and Saturn on the compositions and orbits of the inner planets. Additional information is contained in the original extended abstract.

  19. Reflected Light from Giant Planets in Habitable Zones: Tapping into the Power of the Cross-Correlation Function

    NASA Astrophysics Data System (ADS)

    Martins, J. H. C.; Santos, N. C.; Figueira, P.; Melo, C.

    2016-11-01

    The direct detection of reflected light from exoplanets is an excellent probe for the characterization of their atmospheres. The greatest challenge for this task is the low planet-to-star flux ratio, which even in the most favourable case is of the order of 10-4 in the optical. This ratio decreases even more for planets in their host's habitable zone, typically lower than 10-7. To reach the signal-to-noise level required for such detections, we propose to unleash the power of the Cross Correlation Function in combination with the collecting power of next generation observing facilities. The technique we propose has already yielded positive results by detecting the reflected spectral signature of 51 Pegasi b (see Martins et al. 2015). In this work, we attempted to infer the number of hours required for the detection of several planets in their host's habitable zone using the aforementioned technique from theoretical EELT observations. Our results show that for 5 of the selected planets it should be possible to directly recover their reflected spectral signature.

  20. Contamination from a nearby star cannot explain the anomalous transmission spectrum of the ultrashort period giant planet WASP-103 b

    NASA Astrophysics Data System (ADS)

    Southworth, John; Evans, Daniel F.

    2016-11-01

    The planet in the WASP-103 system is an excellent candidate for transmission spectroscopy because of its large radius and high temperature. Application of this technique found a variation of radius with wavelength which was far too strong to be explained by scattering processes in the planetary atmosphere. A faint nearby star was subsequently detected, whose contamination of the transit light curves might explain this anomaly. We present a reanalysis of published data in order to characterize the faint star and assess its effect on the measured transmission spectrum. The faint star has a mass of 0.72 ± 0.08 M⊙ and is almost certainly gravitationally bound to the planetary system. We find that its effect on the measured physical properties of the planet and host star is small, amounting to a planetary radius larger by 0.6σ and planetary density smaller by 0.8σ. Its influence on the measured transmission spectrum is much greater: the spectrum now has a minimum around 760 nm and opacity rises to both bluer and redder wavelengths. It is a poor match to theoretical spectra and the spectral slope remains too strong for Rayleigh scattering. The existence of the faint nearby star cannot therefore explain the measured spectral properties of this hot and inflated planet. We advocate further observations of the system, both with high spatial resolution in order to improve the measured properties of the faint star, and with higher spectral resolution to confirm the anomalous transmission spectrum of the planet.

  1. The gravitational signature of internal flows in giant planets: Comparing the thermal wind approach with barotropic potential-surface methods

    NASA Astrophysics Data System (ADS)

    Kaspi, Y.; Davighi, J. E.; Galanti, E.; Hubbard, W. B.

    2016-09-01

    The upcoming Juno and Cassini gravity measurements of Jupiter and Saturn, respectively, will allow probing the internal dynamics of these planets through accurate analysis of their gravity spectra. To date, two general approaches have been suggested for relating the flow velocities and gravity fields. In the first, barotropic potential surface models, which naturally take into account the oblateness of the planet, are used to calculate the gravity field. However, barotropicity restricts the flows to be constant along cylinders parallel to the rotation axis. The second approach, calculated in the reference frame of the rotating planet, assumes that due to the large scale and rapid rotation of these planets, the winds are to leading order in geostrophic balance. Therefore, thermal wind balance relates the wind shear to the density gradients. While this approach can take into account any internal flow structure, it is limited to only calculating the dynamical gravity contributions, and has traditionally assumed spherical symmetry. This study comes to relate the two approaches both from a theoretical perspective, showing that they are analytically identical in the barotropic limit, and numerically, through systematically comparing the different model solutions for the gravity harmonics. For the barotropic potential surface models we employ two independent solution methods - the potential-theory and Maclaurin spheroid methods. We find that despite the sphericity assumption, in the barotropic limit the thermal wind solutions match well the barotropic oblate potential-surface solutions.

  2. The Penn State - Toruń Centre for Astronomy Planet Search stars. II. Lithium abundance analysis of the red giant clump sample

    NASA Astrophysics Data System (ADS)

    Adamów, M.; Niedzielski, A.; Villaver, E.; Wolszczan, A.; Nowak, G.

    2014-09-01

    Context. Standard stellar evolution theory does not predict existence of Li-rich giant stars. Several mechanisms for Li-enrichment have been proposed to operate at certain locations inside some stars. The actual mechanism operating in real stars is still unknown. Aims: Using the sample of 348 stars from the Penn State - Toruń Centre for Astronomy Planet Search, for which uniformly determined atmospheric parameters are available, with chemical abundances and rotational velocities presented here, we investigate various channels of Li enrichment in giants. We also study Li-overabundant giants in more detail in search for origin of their peculiarities. Methods: Our work is based on the Hobby-Eberly Telescope spectra obtained with the High Resolution Spectrograph, which we use for determination of abundances and rotational velocities. The Li abundance was determined from the 7Li λ670.8 nm line, while we use a more extended set of lines for α-elements abundances. In a series of Kolmogorov-Smirnov tests, we compare Li-overabundant giants with other stars in the sample. We also use available IR photometric and kinematical data in search for evidence of mass-loss. We investigate properties of the most Li-abundant giants in more detail by using multi-epoch precise radial velocities. Results: We present Li and α-elements abundances, as well as rotational velocities for 348 stars. We detected Li in 92 stars, of which 82 are giants. Eleven of them show significant Li abundance A(Li)NLTE> 1.4 and seven of them are Li-overabundant objects, according to common criterion of A(Li) > 1.5 and their location on HR diagram, including TYC 0684-00553-1 and TYC 3105-00152-1, which are two giants with Li abundances close to meteoritic level. For another 271 stars, upper limits of Li abundance are presented. We confirmed three objects with increased stellar rotation. We show that Li-overabundant giants are among the most massive stars from our sample and show larger than average

  3. Survival of habitable planets in unstable planetary systems

    NASA Astrophysics Data System (ADS)

    Carrera, Daniel; Davies, Melvyn B.; Johansen, Anders

    2016-09-01

    Many observed giant planets lie on eccentric orbits. Such orbits could be the result of strong scatterings with other giant planets. The same dynamical instability that produces these scatterings may also cause habitable planets in interior orbits to become ejected, destroyed, or be transported out of the habitable zone. We say that a habitable planet has resilient habitability if it is able to avoid ejections and collisions and its orbit remains inside the habitable zone. Here we model the orbital evolution of rocky planets in planetary systems where giant planets become dynamically unstable. We measure the resilience of habitable planets as a function of the observed, present-day masses and orbits of the giant planets. We find that the survival rate of habitable planets depends strongly on the giant planet architecture. Equal-mass planetary systems are far more destructive than systems with giant planets of unequal masses. We also establish a link with observation; we find that giant planets with present-day eccentricities higher than 0.4 almost never have a habitable interior planet. For a giant planet with an present-day eccentricity of 0.2 and semimajor axis of 5 AU orbiting a Sun-like star, 50% of the orbits in the habitable zone are resilient to the instability. As semimajor axis increases and eccentricity decreases, a higher fraction of habitable planets survive and remain habitable. However, if the habitable planet has rocky siblings, there is a significant risk of rocky planet collisions that would sterilize the planet.

  4. PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS

    SciTech Connect

    Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

    2009-07-10

    We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets. When planetesimals are included the outcome depends upon the total mass of the planets. For M {sub tot} {approx}> 1 M{sub J} the final eccentricity distribution remains broad, whereas for M {sub tot} {approx}< 1 M{sub J} a combination of divergent orbital evolution and recircularization of scattered planets results in a preponderance of nearly circular final orbits. We also study the fate of marginally stable multiple planet systems in the presence of planetesimal disks, and find that for high planet masses the majority of such systems evolve into resonance. A significant fraction leads to resonant chains that are planetary analogs of Jupiter's Galilean satellites. We predict that a transition from eccentric to near-circular orbits will be observed once extrasolar planet surveys detect sub-Jovian mass planets at orbital radii of a {approx_equal} 5-10 AU.

  5. ON THE ORBITAL EVOLUTION OF A GIANT PLANET PAIR EMBEDDED IN A GASEOUS DISK. I. JUPITER-SATURN CONFIGURATION

    SciTech Connect

    Zhang Hui; Zhou Jilin

    2010-05-01

    We carry out a series of high-resolution (1024 x 1024) hydrodynamical simulations to investigate the orbital evolution of Jupiter and Saturn embedded in a gaseous protostellar disk. Our work extends the results in the classical papers of Masset and Snellgrove and Morbidelli and Crida by exploring various surface density profiles ({sigma}), where {sigma} {proportional_to} r {sup -{alpha}}. The stability of the mean motion resonances (MMRs) caused by the convergent migration of the two planets is studied as well. Our results show that (1) the gap formation process of Saturn is greatly delayed by the tidal perturbation of Jupiter. These perturbations cause inward or outward runaway migration of Saturn, depending on the density profiles on the disk. (2) The convergent migration rate increases as {alpha} increases and the type of MMRs depends on {alpha} as well. When 0 < {alpha} < 1, the convergent migration speed of Jupiter and Saturn is relatively slow, thus they are trapped into 2:1 MMR. When {alpha}>4/3, Saturn passes through the 2:1 MMR with Jupiter and is captured into the 3:2 MMR. (3) The 3:2 MMR turns out to be unstable when the eccentricity of Saturn (e{sub s} ) increases too high. The critical value above which instability will set in is e{sub s} {approx} 0.15. We also observe that the two planets are trapped into 2:1 MMR after the break of 3:2 MMR. This process may provide useful information for the formation of orbital configuration between Jupiter and Saturn in the solar system.

  6. Modelling the effect of radially variable conductivity on dynamo action and zonal flow in the Giant planets

    NASA Astrophysics Data System (ADS)

    Heimpel, M.; Gomez Perez, N.

    2009-05-01

    The surface winds and magnetic fields of Jupiter and Saturn are observed to be broadly comparable. Both planets have strong and prograde equatorial jet and weaker jets, flowing in alternating directions at higher latitudes. Also, both planets exhibit relatively strong, dipolar magnetic fields. Saturn's magnetic field is weaker and more axisymmetric than that of Jupiter. In addition, Saturn's equatorial jet is broader and stronger than that of Jupiter. We have performed a set of numerical simulations of rotating convection and dynamo action in spherical shells. The model fluid is Boussinesq with radially varying electrical conductivity. The electrical conductivity, which is nearly constant in the deeper parts of the shell, exponentially decreases outward, starting at a chosen radius parameter. We find that the character of the dynamo-generated magnetic field, and the fluid flow structure are strongly affected by the afore-mentioned radius parameter, as well as by the size of the inner boundary radius and the temperature boundary conditions. In some of the simulations a strong, magnetostrophic, mainly dipolar dynamo develops in the deeper region of high electrical conductivity. In most cases, a strong zonal flow with an equatorial jet develops near the low-conductivity, free slip outer surface, and penetrates to a depth associated with the conductivity profile. The zonal flow is attenuated by Lorentz forces at depth and is, in some cases, greatly diminished in the dynamo region. The relationship between the structure of equatorial jets and the magnetic fields generated in our models implies that major differences between the surface zonal flow and magnetic fields of Jupiter and Saturn can arise from the presence of a rocky core, and the depth of transition from their low-conductivity molecular envelopes to their liquid metal interiors.

  7. HIGH PRECISION ABUNDANCES IN THE 16 Cyg BINARY SYSTEM: A SIGNATURE OF THE ROCKY CORE IN THE GIANT PLANET

    SciTech Connect

    Maia, Marcelo Tucci; Meléndez, Jorge

    2014-08-01

    We study the stars of the binary system 16 Cygni to determine with high precision their chemical composition. Knowing that the component B has a detected planet of at least 1.5 Jupiter masses, we investigate if there are chemical peculiarities that could be attributed to planet formation around this star. We perform a differential abundance analysis using high resolution (R = 81,000) and high S/N (∼700) CFHT/ESPaDOnS spectra of the 16 Cygni stars and the Sun; the latter was obtained from light reflected of asteroids. We determine differential abundances of the binary components relative to the Sun and between components A and B as well. We achieve a precision of σ ≲ 0.005 dex and a total error ∼0.01 dex for most elements. The effective temperatures and surface gravities found for 16 Cyg A and B are T {sub eff} = 5830 ± 7 K, log g = 4.30 ± 0.02 dex, and T {sub eff} = 5751 ± 6 K, log g = 4.35 ± 0.02 dex, respectively. The component 16 Cyg A has a metallicity ([Fe/H]) higher by 0.047 ± 0.005 dex than 16 Cyg B, as well as a microturbulence velocity higher by 0.08 km s{sup –1}. All elements show abundance differences between the binary components, but while the volatile difference is about 0.03 dex, the refractories differ by more and show a trend with condensation temperature, which could be interpreted as the signature of the rocky accretion core of the giant planet 16 Cyg Bb. We estimate a mass of about 1.5-6 M {sub ⊕} for this rocky core, in good agreement with estimates of Jupiter's core.

  8. Atom Resonance Lines for Modeling Atmosphere: Studies of Pressure-Broadening of Alkali Atom Resonance Lines for Modeling Atmospheres of Extrasolar Giant Planets and Brown Dwarfs

    NASA Technical Reports Server (NTRS)

    Hasan, Hashima (Technical Monitor); Kirby, K.; Babb, J.; Yoshino, K.

    2005-01-01

    We report on progress made in a joint program of theoretical and experimental research to study the line-broadening of alkali atom resonance lines due to collisions with species such as helium and molecular hydrogen. Accurate knowledge of the line profiles of Na and K as a function of temperature and pressure will allow such lines to serve as valuable diagnostics of the atmospheres of brown dwarfs and extra-solar giant planets. A new experimental apparatus has been designed, built and tested over the past year, and we are poised to begin collecting data on the first system of interest, the potassium resonance lines perturbed by collisions with helium. On the theoretical front, calculatio