Sample records for extrasolar planetary atmospheres

  1. Ionisation in ultra-cool, cloud forming extrasolar planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Helling, Christiane; the LEAP Team

    2015-04-01

    Transit spectroscopy provides evidence that extrasolare planets are covered in clouds, a finding that has been forecast by cloud model simulations 15 years ago. Atmospheres are strongly affected by clouds through their large opacity and their chemical activity. Cloud formation models allow to predict cloud particle sizes, their chemical composition and the composition of the remaining atmospheric gas (Woitke & Helling 2004, A&A 414; Helling & Woitke 2006, A&A 455), for example, as input for radiative transfer codes like Drift-Phoenix (Witte et al. 2009; A&A 506). These cloud particles are charged and can discharge, for example in form of lighting (Helling et al. 2013, ApJ 767; Bailey et al. 2014, ApJ 784). Earth observations demonstrate that lighting effects not only the local chemistry but also the electron budget of the atmosphere. This talk will present our work on cloud formation modelling and ionisation processes in cloud forming atmospheres. An hierarchy of ionisation processes leads to a vertically inhomogenously ionised atmosphere which has implications for planetary mass loss and global circulation pattern of planetary atmospheres. Processes involved, like Cosmic Ray ionisation, do also activate the local chemistry such that large hydrocarbon molecules form (Rimmer et al. 2014, IJAsB 13).

  2. Transonic Hydrodynamic Escape of Hydrogen from Extrasolar Planetary Atmospheres

    Microsoft Academic Search

    Feng Tian; Owen B. Toon; Alexander A. Pavlov; H. De Sterck

    2005-01-01

    Hydrodynamic escape is an important process in the formation and evolution of planetary atmospheres. Tran- sonic steady state solutions of the time-independent hydrodynamic equations are difficult to find because of the existence of a singularity point. A numerical model is developed to study the hydrodynamic escape of neutral gas from planetary atmospheres by solving the time-dependent hydrodynamic equations. The model

  3. Atmospheric Lensing and Oblateness Effects during an Extrasolar Planetary Transit

    Microsoft Academic Search

    Lam Hui; Sara Seager

    2002-01-01

    Future high-precision photometric measurements of transiting extrasolar planets promise to tell us much about the characteristics of these systems. We examine how atmospheric lensing and (projected) planet oblateness\\/ellipticity modify transit light curves. The large density gradients expected in planet atmospheres can offset the unfavorably large observer lens-to-source lens distance ratio and allow the existence of caustics. Under such conditions of

  4. The Atmospheres of Extrasolar Planets

    NASA Technical Reports Server (NTRS)

    Richardson, L. J.; Seager, S.

    2007-01-01

    In this chapter we examine what can be learned about extrasolar planet atmospheres by concentrating on a class of planets that transit their parent stars. As discussed in the previous chapter, one way of detecting an extrasolar planet is by observing the drop in stellar intensity as the planet passes in front of the star. A transit represents a special case in which the geometry of the planetary system is such that the planet s orbit is nearly edge-on as seen from Earth. As we will explore, the transiting planets provide opportunities for detailed follow-up observations that allow physical characterization of extrasolar planets, probing their bulk compositions and atmospheres.

  5. Atmospheres of Extrasolar Giant Planets

    E-print Network

    Mark S. Marley; Jonathan Fortney; Sara Seager; Travis Barman

    2006-02-21

    The key to understanding an extrasolar giant planet's spectrum--and hence its detectability and evolution--lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of extrasolar giant planets and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a single stellar system leads to the study of comparative planetary architectures.

  6. Planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Leovy, C.

    1987-03-01

    Observations and theoretical models of planetary atmospheres published during the period 1983-1986 are reviewed, including Vega and Voyager data and results from ground-based remote sensing. Consideration is given to water-vapor and sulfur-compound distributions, electrical phenomena, and dynamics in the Venus atmosphere; dust storms, water cycles, and water and ice erosion on Mars; the compositions, temperature profiles, and dynamics of the Jovian and Saturnian atmospheres; chemical processes and zonal winds on Titan; and the radiation budgets and chemical compositions of the outer planets.

  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. Specific Angular Momentum of Extrasolar Planetary Systems

    E-print Network

    John C. Armstrong; Shane L. Larson; Rhett R. Zollinger

    2011-09-02

    As the number of known planetary systems increases, the ability to follow-up and characterize the extent of any system becomes limited. This paper considers the use of specific angular momentum as a metric to prioritize future observations. We analyze 431 planets in 367 known extrasolar planetary systems from Butler et al. (2006) (including updates to their online catalog, current to April, 2011) and estimate each system's orbital angular momentum. The range of partition- ing of specific angular momentum in these systems is found to be large, spanning several orders of magnitude. The analysis shows that multi-planet systems tend to have the highest values of specific angular momentum normalized against the planetary masses. This suggests that in high angular momentum systems, the dominant contributors have already been discovered, and that single-planet sys- tems with low observed angular momentum may be the most likely candidates for additional undiscovered companions compared to their high angular momentum, single-planet counterparts. The multi-planet system, GJ 581, is considered as a historical case study to demonstrate the concept, examining how the specific angular momentum of the know planetary system evolved with each discovery.

  9. Stellar Ablation of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.; Horwitz, J. L.

    2007-01-01

    We review observations and theories of the solar ablation of planetary atmospheres, focusing on the terrestrial case where a large magnetosphere holds off the solar wind, so that there is little direct atmospheric impact, but also couples the solar wind electromagnetically to the auroral zones. We consider the photothermal escape flows known as the polar wind or refilling flows, the enhanced mass flux escape flows that result from localized solar wind energy dissipation in the auroral zones, and the resultant enhanced neutral atom escape flows. We term these latter two escape flows the "auroral wind." We review observations and theories of the heating and acceleration of auroral winds, including energy inputs from precipitating particles, electromagnetic energy flux at magnetohydrodynamic and plasma wave frequencies, and acceleration by parallel electric fields and by convection pickup processes also known as "centrifugal acceleration." We consider also the global circulation of ionospheric plasmas within the magnetosphere, their participation in magnetospheric disturbances as absorbers of momentum and energy, and their ultimate loss from the magnetosphere into the downstream solar wind, loading reconnection processes that occur at high altitudes near the magnetospheric boundaries. We consider the role of planetary magnetization and the accumulating evidence of stellar ablation of extrasolar planetary atmospheres. Finally, we suggest and discuss future needs for both the theory and observation of the planetary ionospheres and their role in solar wind interactions, to achieve the generality required for a predictive science of the coupling of stellar and planetary atmospheres over the full range of possible conditions.

  10. Planetary Science (mostly atmospheres)

    E-print Network

    Withers, Paul

    Planetary Science (mostly atmospheres) at Boston University Paul Withers withers@bu.edu Planetary Science Decadal Survey Town Hall Meeting Boston University 2011.03.26 #12;Selected people Supriya John

  11. Extrasolar Planetary Imaging Coronagraph: Visible Nulling Coronagraph Testbed Results

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.

    2008-01-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC will provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F stars, observed the inner spatial structure and colors of inner Spitzer selected debris disks. EPIC would be launched to heliocentric Earth trailing drift-away orbit, with a 3-year mission lifetime ( 5 year goal) and will revisit planets at least three times at intervals of 9 months. The starlight suppression approach consists of a visible nulling coronagraph (VNC) that enables high order starlight suppression in broadband light. To demonstrate the VNC approach and advance it's technology readiness the NASA Goddard Space Flight Center and Lockheed-Martin have developed a laboratory VNC and have demonstrated white light nulling. We will discuss our ongoing VNC work and show the latest results from the VNC testbed,

  12. Uses of Linear Polarization as a Probe of Extrasolar Planet Atmospheres

    E-print Network

    S. Saar; S. Seager

    2003-05-22

    We point out some advantages of making observations of extrasolar planets in linearly polarized (LP) light. Older cool stars have quite low levels (~ 10^-4 to 10^-5) of fractional LP, while extrasolar planets can have relatively high fractional LP (~0.1). Observations in LP light can therefore significantly enhance contrast between the planet and its parent star. Data on LP as a function of planetary orbital phase can be used to diagnose the properties (e.g., composition, size, and shape) of the scatterers in the planetary atmosphere. We discuss the feasibility of LP observations of extrasolar planets.

  13. Transmission Spectra as Diagnostics of Extrasolar Giant Planet Atmospheres

    E-print Network

    Timothy M. Brown

    2001-01-17

    Atmospheres of transiting extrasolar giant planets (EGPs) such as HD 209458 b must impose features on the spectra of their parent stars during transits; these features contain information about the physical conditions and chemical composition of the atmospheres. The most convenient observational index showing these features is the ``spectrum ratio'', defined as the wavelength-dependent ratio of spectra taken in and out of transit. I describe a model that estimates this ratio and its dependence upon parameters of the planetary atmosphere, including its cloud structure, temperature, chemical composition, and wind fields. For giant planets in close orbits, the depths of atomic and molecular features in the spectrum ratio may be as large as 0.001. Observations in visible and near-IR wavelengths using existing and planned spectrographs should be adequate to detect these features, and to provide some diagnostics of the conditions within the planetary atmosphere. I give numerous examples of such diagnostics, and I discuss their practicality.

  14. Exploring Extrasolar Planetary Systems: New Observations of Extrasolar Planets Enabled by the James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Clampin, Mark

    2012-01-01

    The search for extrasolar planets has been increasingly success over the last few years. In excess of 700 systems are now known, and Kepler has approx.2500 additional candidate systems, yet to be confirmed. Recently, progress has also been made in directly imaging extrasolar planets, both from the ground and in space. In this presentation will discuss the techniques employed to discover planetary systems, and highlight the capabilities, enabled by the James Webb Space Telescope (JWST). JWST is a large 6.5 meter aperture infrared telescope that is scheduled for launch in 2018, and will allow us to transition to characterizing the properties of these extrasolar planets and the planetary systems in which they reside.

  15. Space Science I: Planetary Atmospheres

    E-print Network

    Johnson, Robert E.

    Space Science I: Planetary Atmospheres Atmospheric Structure and Transport Origins and Evolution of Planetary Atmospheres Books The New Solar System Chapters 8,9,11,13,15,17,18,20 #12;Space Science I, is crucial and is one goal of this course. #12;Space Science I: Planetary Atmospheres Goals To understand- 1

  16. Inclination Excitation in Compact Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Becker, Juliette; Adams, Fred C.

    2015-05-01

    The Kepler Mission has detected dozens of compact planetary systems with more than four transiting planets. This sample provides a collection of close-packed planetary systems with relatively little spread in the inclination angles of the inferred orbits. We have explored the effectiveness of dynamical mechanisms in exciting orbital inclination in this class of solar systems. The two mechanisms we discuss are self-excitation of orbital inclination in initially (nearly) coplanar planetary systems and perturbations by additional unseen larger bodies in the outer regions of the solar systems. For both of these scenarios, we determine the regimes of parameter space for which orbital inclination can be effectively excited. For compact planetary systems with the observed architectures, we find that the orbital inclination angles are not spread out appreciably through self-excitation, resulting in a negligible scatter in impact parameter and a subsequently stable transiting system. In contrast, companions in the outer solar system can be effective in driving variations of the inclination angles of the inner planetary orbits, leading to significant scatter in impact parameter and resultantly non-transiting systems. We present the results of our study, the regimes in which each excitation method - self-excitation of inclination and excitation by a perturbing secondary - are relevant, and the magnitude of the effects.

  17. Theoretical Spectra and Atmospheres of Extrasolar Giant Planets

    Microsoft Academic Search

    David Sudarsky; Adam Burrows; Ivan Hubeny

    2003-01-01

    We present a comprehensive theory of the spectra and atmospheres of irradiated extrasolar giant planets. We explore the dependences on stellar type, orbital distance, cloud characteristics, planet mass, and surface gravity. Phase-averaged spectra for specific known extrasolar giant planets that span a wide range of the relevant parameters are calculated, plotted, and discussed. The connection between atmospheric composition and emergent

  18. IONIZATION OF EXTRASOLAR GIANT PLANET ATMOSPHERES

    SciTech Connect

    Koskinen, Tommi T. [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ (United States); Cho, James Y-K. [Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Achilleos, Nicholas; Aylward, Alan D., E-mail: tommi@lpl.arizona.ed [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    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.

  19. 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 the effect of stellar distance (e.g., incident ultraviolet flux, atmospheric temperature) on the chemical properties of EGPs. The model is applied to two generic Class II and III intermediate temperature EGPs located at 3.3 and 0.27 AU from a solar-like parent star, and the results are compared with a model for Jupiter at 5.2 AU.

  20. On Orbital Elements of Extrasolar Planetary Candidates and Spectroscopic Binaries

    NASA Technical Reports Server (NTRS)

    Stepinski, T. F.; Black, D. C.

    2001-01-01

    We estimate probability densities of orbital elements, periods, and eccentricities, for the population of extrasolar planetary candidates (EPC) and, separately, for the population of spectroscopic binaries (SB) with solar-type primaries. We construct empirical cumulative distribution functions (CDFs) in order to infer probability distribution functions (PDFs) for orbital periods and eccentricities. We also derive a joint probability density for period-eccentricity pairs in each population. Comparison of respective distributions reveals that in all cases EPC and SB populations are, in the context of orbital elements, indistinguishable from each other to a high degree of statistical significance. Probability densities of orbital periods in both populations have P(exp -1) functional form, whereas the PDFs of eccentricities can he best characterized as a Gaussian with a mean of about 0.35 and standard deviation of about 0.2 turning into a flat distribution at small values of eccentricity. These remarkable similarities between EPC and SB must be taken into account by theories aimed at explaining the origin of extrasolar planetary candidates, and constitute an important clue us to their ultimate nature.

  1. Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets.

    PubMed

    Des Marais, David J; Harwit, Martin O; Jucks, Kenneth W; Kasting, James F; Lin, Douglas N C; Lunine, Jonathan I; Schneider, Jean; Seager, Sara; Traub, Wesley A; Woolf, Neville J

    2002-01-01

    The major goals of NASA's Terrestrial Planet Finder (TPF) and the European Space Agency's Darwin missions are to detect terrestrial-sized extrasolar planets directly and to seek spectroscopic evidence of habitable conditions and life. Here we recommend wavelength ranges and spectral features for these missions. We assess known spectroscopic molecular band features of Earth, Venus, and Mars in the context of putative extrasolar analogs. The preferred wavelength ranges are 7-25 microns in the mid-IR and 0.5 to approximately 1.1 microns in the visible to near-IR. Detection of O2 or its photolytic product O3 merits highest priority. Liquid H2O is not a bioindicator, but it is considered essential to life. Substantial CO2 indicates an atmosphere and oxidation state typical of a terrestrial planet. Abundant CH4 might require a biological source, yet abundant CH4 also can arise from a crust and upper mantle more reduced than that of Earth. The range of characteristics of extrasolar rocky planets might far exceed that of the Solar System. Planetary size and mass are very important indicators of habitability and can be estimated in the mid-IR and potentially also in the visible to near-IR. Additional spectroscopic features merit study, for example, features created by other biosignature compounds in the atmosphere or on the surface and features due to Rayleigh scattering. In summary, we find that both the mid-IR and the visible to near-IR wavelength ranges offer valuable information regarding biosignatures and planetary properties; therefore both merit serious scientific consideration for TPF and Darwin. PMID:12469366

  2. Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets

    NASA Technical Reports Server (NTRS)

    Des Marais, David J.; Harwit, Martin O.; Jucks, Kenneth W.; Kasting, James F.; Lin, Douglas N C.; Lunine, Jonathan I.; Schneider, Jean; Seager, Sara; Traub, Wesley A.; Woolf, Neville J.

    2002-01-01

    The major goals of NASA's Terrestrial Planet Finder (TPF) and the European Space Agency's Darwin missions are to detect terrestrial-sized extrasolar planets directly and to seek spectroscopic evidence of habitable conditions and life. Here we recommend wavelength ranges and spectral features for these missions. We assess known spectroscopic molecular band features of Earth, Venus, and Mars in the context of putative extrasolar analogs. The preferred wavelength ranges are 7-25 microns in the mid-IR and 0.5 to approximately 1.1 microns in the visible to near-IR. Detection of O2 or its photolytic product O3 merits highest priority. Liquid H2O is not a bioindicator, but it is considered essential to life. Substantial CO2 indicates an atmosphere and oxidation state typical of a terrestrial planet. Abundant CH4 might require a biological source, yet abundant CH4 also can arise from a crust and upper mantle more reduced than that of Earth. The range of characteristics of extrasolar rocky planets might far exceed that of the Solar System. Planetary size and mass are very important indicators of habitability and can be estimated in the mid-IR and potentially also in the visible to near-IR. Additional spectroscopic features merit study, for example, features created by other biosignature compounds in the atmosphere or on the surface and features due to Rayleigh scattering. In summary, we find that both the mid-IR and the visible to near-IR wavelength ranges offer valuable information regarding biosignatures and planetary properties; therefore both merit serious scientific consideration for TPF and Darwin.

  3. Detectability of planetary rings around an extrasolar planet from reflected-light photometry

    E-print Network

    L. Arnold; J. Schneider

    2005-10-19

    The next generation of high-contrast imaging instruments will provide the first unresolved image of an extrasolar planet. While the emitted infrared light from the planet in thermal equilibrium should show almost no phase effect, the reflected visible light will vary with the orbital phase angle. We study the photometric variation of the reflected light with orbital phase of a ringed extrasolar planet. We show that a ring around an extrasolar planet, both obviously unresolved, can be detected by its specific photometric signature. Keywords: Stars: planetary systems -- Planets: rings -- Extrasolar planet characterization

  4. Comparative Understanding of Planetary Atmospheres

    Microsoft Academic Search

    D. L. Huestis; S. K. Atreya; S. J. Bolton; S. W. Bougher; A. Coustenis; S. G. Edgington; A. J. Friedson; C. A. Griffith; S. L. Guberman; H. B. Hammel; J. I. Lunine; M. Mendillo; J. Moses; I. Mueller-Wodarg; G. S. Orton; K. A. Rages; T. G. Slanger; D. V. Titov; R. Yelle

    2001-01-01

    Observing, characterizing, and understanding planetary atmospheres are key components of solar system exploration. A planet's atmosphere is the interface between the surface and external energy and mass sources. Understanding how atmospheres are formed, evolve, and respond to perturbations is essential for addressing the long-range science objectives of identifying the conditions that are favorable for producing and supporting biological activity, managing

  5. The 1/1 Resonance in Extrasolar Planetary Systems John D. Hadjidemetriou1

    E-print Network

    Hadjidemetriou, John D.

    are in antialignment and in the unstable family the planetary orbits are in alignment. Along the stable resonant familyThe 1/1 Resonance in Extrasolar Planetary Systems John D. Hadjidemetriou1 , Dionyssia Psychoyos2 planets, for planar motion, at the 1/1 resonance. This means that the semimajor axes of the two planets

  6. PICTURE: a sounding rocket experiment for direct imaging of an extrasolar planetary environment

    E-print Network

    PICTURE: a sounding rocket experiment for direct imaging of an extrasolar planetary environment 90278, USA ABSTRACT The Planetary Imaging Concept Testbed Using a Rocket Experiment (PICTURE 36.225 UG.5 AU. PICTURE carried four key enabling technologies on board a NASA sounding rocket at 4:25 MDT

  7. The signature of hot hydrogen in the atmosphere of the extrasolar planet HD 209458b.

    PubMed

    Ballester, Gilda E; Sing, David K; Herbert, Floyd

    2007-02-01

    About ten per cent of the known extrasolar planets are gas giants that orbit very close to their parent stars. The atmospheres of these 'hot Jupiters' are heated by the immense stellar irradiation. In the case of the planet HD 209458b, this energy deposition results in a hydrodynamic state in the upper atmosphere, allowing for sizeable expansion and escape of neutral hydrogen gas. HD 209458b was the first extrasolar planet discovered that transits in front of its parent star. The size of the planet can be measured using the total optical obscuration of the stellar disk during an observed transit, and the structure and composition of the planetary atmosphere can be studied using additional planetary absorption signatures in the stellar spectrum. Here we report the detection of absorption by hot hydrogen in the atmosphere of HD 209458b. Previously, the lower atmosphere and the full extended upper atmosphere of HD 209458b have been observed, whereas here we probe a layer where the escaping gas forms in the upper atmosphere of HD 209458b. PMID:17268463

  8. About putative Neptune-like extrasolar planetary candidates

    E-print Network

    Krzysztof Gozdziewski; Cezary Migaszewski

    2005-11-10

    We re-analyze the precision radial velocity (RV) data of HD188015, HD114729, HD190360, HD147513 and HD208487. All these stars are supposed to host Jovian companions in long-period orbits. We test a hypothesis that the residuals of the 1-planet model of the RV or an irregular scatter of the measurements about the synthetic RV curve may be explained by the existence of additional planets in short-period orbits. We perform a global search for the best fits in the orbital parameters space with genetic algorithms and simplex method. This makes it possible to verify and extend the results obtained with an application of commonly used FFT-based periodogram analysis for identifying the leading periods. Our analysis confirms the presence of a periodic component in the RV data of HD190360 which may correspond to a hot-Neptune planet. We found four new cases when the 2-planet model yields significantly better fits to the RV data than the best 1-planet solutions. If the periodic variability of the residuals of single-planet fits has indeed a planetary origin then hot-Neptune planets may exist in these extrasolar systems. We estimate their orbital periods in the range of 7-20d and minimal masses about of 20 masses od the Earth.

  9. The Virtual Planetary Laboratory: Towards Characterizing Extrasolar Terrestrial Planets

    Microsoft Academic Search

    V. S. Meadows; M. Allen; L. Brown; D. Crisp; A. Fijany; M. Storrie-Lombardi; E. Ustinov; T. Velusamy; M. Richardson; Y. Yung; W. Huntress; D. DesMarais; K. Zahnle; J. Kasting; C. Morrow; N. Sleep; M. Cohen; K. Nealson; R. Rye; M. Coleman

    2001-01-01

    The Virtual Plantary Laboratory (VPL) is a recently funded 5-yr project which seeks to improve our understanding of the range of plausible environments and the likely signatures for life on extrasolar terrestrial planets. To achieve these goals we are developing a suite of innovative modeling tools to simulate the environments and spectra of extrasolar planets. The core of the VPL

  10. Terrestrial Planet Formation in Extra-Solar Planetary Systems

    E-print Network

    Sean N. Raymond

    2008-01-16

    Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called "planetary embryos". Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass and surface density profile of the disk, and the perturbations from giant planets and binary companions if they exist. Simple accretion models predicts that low-mass stars should form small, dry planets in their habitable zones. The migration of a giant planet through a disk of rocky bodies does not completely impede terrestrial planet growth. Rather, "hot Jupiter" systems are likely to also contain exterior, very water-rich Earth-like planets, and also "hot Earths", very close-in rocky planets. Roughly one third of the known systems of extra-solar (giant) planets could allow a terrestrial planet to form in the habitable zone.

  11. Water vapour in the atmosphere of a transiting extrasolar planet

    Microsoft Academic Search

    Giovanna Tinetti; Alfred Vidal-Madjar; Mao-Chang Liang; Jean-Philippe Beaulieu; Yuk Yung; Sean Carey; Robert J. Barber; Jonathan Tennyson; Ignasi Ribas; Nicole Allard; Gilda E. Ballester; David K. Sing; Franck Selsis

    2007-01-01

    Water is predicted to be among the most abundant (if not the most abundant) molecular species after hydrogen in the atmospheres of close-in extrasolar giant planets (`hot Jupiters'). Several attempts have been made to detect water on such planets, but have either failed to find compelling evidence for it or led to claims that should be taken with caution. Here

  12. Clouds in Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    West, R.

    1999-01-01

    In the terrestrial atmosphere clouds are familiar as vast collections of small water drops or ice cyrstals suspended in the air. The study of clouds touches on many facets of armospheric science. The chemistry of clouds is tied to the chemistry of the surrounding atmosphere.

  13. Understanding Microbial Contributions to Planetary Atmosphere

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.

    2000-01-01

    Should our search of distant, extrasolar planetary atmospheres encounter evidence of life, that evidence will most likely be the gaseous products of microorganisms. Our biosphere was exclusively microbial for over 80 percent of its history and, even today, microbes strongly influence atmospheric composition. Life's greatest environmental impact arises from its capacity for harvesting energy and creating organic matter. Microorganisms catalyze the equilibration of C, S and transition metal species at temperatures where such reactions can be very slow in the absence of life. Sunlight has been harvested through photosynthesis to create enormous energy reservoirs that exist in the form of coexisting reservoirs of reduced, organic C and S stored in Earth's crust, and highly oxidized species (oxygen, sulfate and ferric iron) stored in the crust, oceans and atmosphere. Our civilization taps that storehouse of energy by burning fossil fuels. As astrobiologists, we identify the chemical consequences of distant biospheres as expressed in the atmospheres of their planets. Our approach must recognize that planets, biospheres and atmospheres evolve and change. For example, a tectonically more active early Earth hosted a thermophilic, non-photosynthetic biosphere and a mildly reducing, carbon dioxide-rich and oxygen-poor atmosphere. Microorganisms acquired energy by consuming hydrogen and sulfide and producing a broad array of reduced C and S gases, most notably, methane. Later, diverse types of bacterial photosynthesis developed that enhanced productivity but were incapable of splitting water to produce oxygen. Later, but still prior to 2.6 billion years ago, oxygenic photosynthesis developed. We can expect to encounter distant biospheres that represent various stages of evolution and that coexist with atmospheres ranging from mildly reducing to oxidizing compositions. Accordinaly, we must be prepared to interpret a broad range of atmospheric compositions, all containing signatures of life. Remarkably little is known about the composition of our own earlier atmosphere, particularly prior to the rise of oxygen levels some 2.0 to 2.2 billion years ago. Thus, field and laboratory observations and theoretical simulations should be conducted to examine the relationships between the structure and function of microbial ecosystems and their gaseous products. Ecosystems that are analogs of our ancient biosphere (e.g., based upon chemosynthesis or non-oxygenic photosynthesis, thermophilic and subsurface communities, etc.) should be included. Because key environmental parameters such as temperature and levels of hydrogen, carbon dioxide and oxygen varied during planetary evolution, their consequences for microbial ecosystems should be explored.

  14. Phase-Dependent Properties of Extrasolar Planet Atmospheres

    Microsoft Academic Search

    Travis S. Barman; Peter H. Hauschildt; France Allard

    2005-01-01

    Recently the Spitzer Space Telescope observed the transiting extrasolar\\u000aplanets, TrES-1 and HD209458b. These observations have provided the first\\u000aestimates of the day side thermal flux from two extrasolar planets orbiting\\u000aSun-like stars. In this paper, synthetic spectra from atmospheric models are\\u000acompared to these observations. The day-night temperature difference is\\u000aexplored and phase-dependent flux densities are predicted for both

  15. Sprites in other planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Yair, Y.; Yaniv, R.

    Lightning have been detected in clouds on other planets either by direct imaging of the optical emissions from flashes emanating through the atmosphere or else by remote sensing of electromagnetic signals such as sferics or whistlers guided by the planet's magnetosphere. While the intensity of the electrical activity on Venus may be still inconclusive, there is little doubt, based on the Voyager, Galileo and Cassini missions, that lightning are prevalent on Jupiter and Saturn, and that their total power is much stronger than on Earth (Desch et al., 2002; Gurnett et al., 2005). Sprites are a type of a transient luminous emission which accompanies powerful lightning flashes (Lyons et al. 2001). They are caused the quasi-electrostatic electric field between the charged cloud top and the planetary ionosphere. They can take weird and magnificent shapes resembling jelly-fish, carrot heads, pearls or columns. On Earth, they emit in red and blue wavelengths, mostly from molecular Nitrogen species, and span a vertical range between 50 and 90 km. The emission spectra of sprites, their height and occurrence frequency reflect the properties of the planetary atmosphere and are directly related to the intensity of the parent lightning. We present results of theoretical calculations of the expected emissions in sprites, occurring above thunderstorms in the CO2 atmosphere of Venus and the Hydrogen-Helium atmospheres of Jupiter and Saturn. Detection methodology of sprites in planetary atmospheres by orbiting spacecraft will be discussed

  16. Transmission Spectra as Diagnostics of Extrasolar Giant Planet Atmospheres

    Microsoft Academic Search

    Timothy M. Brown

    2001-01-01

    Atmospheres of transiting extrasolar giant planets (EGPs) such as HD 209458 b\\u000amust impose features on the spectra of their parent stars during transits;\\u000athese features contain information about the physical conditions and chemical\\u000acomposition of the atmospheres. The most convenient observational index showing\\u000athese features is the ``spectrum ratio'', defined as the wavelength-dependent\\u000aratio of spectra taken in and

  17. Impact erosion of planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Shuvalov, Valery

    1999-06-01

    The problem of planetary atmospheres evolution due to impacts of large cosmic bodies was investigated by Ahrens, O'Keefe, Cameron, Hunten and others. These studies were focused mainly on the atmosphere growth under impact devolatilization and atmosphere losses due to escape of high velocity ejecta. Most of the results concerning atmosphere erosion were based on assumption that atmosphere itself does not influence significantly on the ejecta evolution. However more detailed investigations show that atmospheric drag is important at least for 1-10km impactors. From the other hand the theory of large explosions in an exponential atmosphere is not applicable in the case under consideration because of the influence of a trail created during the body flight through the atmosphere. In the present study the problem of 1-10km asteroid impacts against the Earth is investigated with the use of multi-material hydrocode SOVA. This code is similar to the widely used CTH system and allows to model all stages of the impact (penetration into the atmosphere, collision with the ground surface covered by water basin, ejecta evolution). The air mass ejected from each altitude depending on impactor size and velocity is determined. Apart from the impacts into the present-day atmosphere, the erosion of the dense Proto-Atmosphere is also considered.

  18. Recognition of the First Observational Evidence of an Extrasolar Planetary System

    NASA Astrophysics Data System (ADS)

    Zuckerman, B.

    2015-06-01

    With 20-20 hindsight, it is now possible to say that the first observational indication – by any means – of the existence of an extrasolar planetary system came almost a century ago when van Maanen discovered and noted the spectrum of the nearest single white dwarf to Earth.

  19. Stability of Earth-Mass Planets in the Habitable Zones of Extrasolar Planetary Systems

    E-print Network

    Bjørnstad, Ottar Nordal

    Stability of Earth-Mass Planets in the Habitable Zones of Extrasolar Planetary Systems Dr. Ravi Kumar Kopparapu Dept. of Geosciences, College of Earth and Mineral Science Over 500 planets orbiting and Saturn but in the last couple of years several "super-earths", planets with mass less than 10 times Earth

  20. Theoretical Spectra and Atmospheres of Extrasolar Giant Planets

    E-print Network

    David Sudarsky; Adam Burrows; Ivan Hubeny

    2003-02-19

    We present a comprehensive theory of the spectra and atmospheres of irradiated extrasolar giant planets. We explore the dependences on stellar type, orbital distance, cloud characteristics, planet mass, and surface gravity. Phase-averaged spectra for specific known extrasolar giant planets that span a wide range of the relevant parameters are calculated, plotted, and discussed. The connection between atmospheric composition and emergent spectrum is explored in detail. Furthermore, we calculate the effect of stellar insolation on brown dwarfs. We review a variety of representative observational techniques and programs for their potential for direct detection, in light of our theoretical expectations, and we calculate planet-to-star flux ratios as a function of wavelength. Our results suggest which spectral features are most diagnostic of giant planet atmospheres and reveal the best bands in which to image planets of whatever physical or orbital characteristics.

  1. The ability of the space telescope to detect extra-solar planetary systems

    NASA Technical Reports Server (NTRS)

    Baum, W. A.

    1979-01-01

    The space telescope can plan a key role in searching for and investigating the contents of extra-solar planetary systems. For about 90 nearby stars, positional variations due to major planets would be well within the astrometric capability of the wide-field/planetary camera system. Since the centroids of star images will be determined to within a milliarcsecond down to 22d magnitude, there will be an abundance of reference stars at very small angular distances from each planetary system candidate, and they will have small enough motions of their own to provide a reference frame of the stability required.

  2. Retrieval of atmospheric properties of extrasolar planets

    E-print Network

    Nikku, Madhusudhan, 1980-

    2009-01-01

    We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. Our method allows us to run millions of 1-D atmosphere models in order to cover the ...

  3. DETECTION OF AN EXTRASOLAR PLANET ATMOSPHERE1

    Microsoft Academic Search

    David Charbonneau; Timothy M. Brown; Robert W. Noyes; Ronald L. Gilliland

    We report high-precision spectrophotometric observations of four planetary transits of HD 209458, in the region of the sodium resonance doublet at 589.3 nm. We find that the photometric dimming during transit in a bandpass centered on the sodium feature is deeper by (2.32 ? 0.57) ? 10? 4 relative to simultaneous obser- vations of the transit in adjacent bands. We

  4. Detection of an Extrasolar Planet Atmosphere

    Microsoft Academic Search

    David Charbonneau; Timothy M. Brown; Robert W. Noyes; Ronald L. Gilliland

    2001-01-01

    We report high precision spectrophotometric observations of four planetary\\u000atransits of HD 209458, in the region of the sodium resonance doublet at 589.3\\u000anm. We find that the photometric dimming during transit in a bandpass centered\\u000aon the sodium feature is deeper by (2.32 +\\/- 0.57) x 10^{-4} relative to\\u000asimultaneous observations of the transit in adjacent bands. We interpret

  5. Extra-Solar Planetary Imager (ESPI) for Space Based Jovian Planetary Detection

    NASA Technical Reports Server (NTRS)

    Lyon, Rick G.; Melnick, Gary J.; Nisenson, Peter; Papaliolios, Costa; Ridgeway, Steve; Friedman, Edward; Gezari, Dan Y.; Harwit, Martin; Graf, Paul

    2002-01-01

    We report on out Extra-Solar Planetary Imager (ESPI) study for a recent Midex (NASA Medium Class Explorer Mission) proposal. Proposed for ESPI was a 1.5 x 1.5 square meter Jacquinot apodized square aperture telescope. The combination of apodization and a square aperture telescope significantly reduces the diffracted light from a bright central source over much of the telescope focal plane. As a result, observations of very faint astronomical objects next to bright sources with angular separations as small as 0.32 arcseconds become possible. This permits a sensitive search for exo-planets in reflected light. The system is capable of detecting a Jupiter-like planet in a relatively long-period orbit around as many as 160 to 175 stars with a signal-to-noise ratio greater than 5 in observations lasting maximally 100 hours per star. We discuss the effects of wavefront error, mirror speckle, pointing error and signal-to-noise issues, as well as the scalability of our ESPI study with respect to NASA's Terrestrial Planet Finder mission.

  6. An extrasolar planetary system with three Neptune-mass planets

    Microsoft Academic Search

    Christophe Lovis; Michel Mayor; Francesco Pepe; Yann Alibert; Willy Benz; François Bouchy; Alexandre C. M. Correia; Jacques Laskar; Christoph Mordasini; Didier Queloz; Nuno C. Santos; Stéphane Udry; Jean-Loup Bertaux; Jean-Pierre Sivan

    2006-01-01

    Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called `hot Neptunes' or `super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15days. Here we report a system of three Neptune-mass planets with periods of 8.67,

  7. Isotopic ratios in planetary atmospheres.

    PubMed

    de Bergh, C

    1995-03-01

    Recent progress on measurements of isotopic ratios in planetary or satellite atmospheres include measurements of the D/H ratio in the methane of Uranus, Neptune and Titan and in the water of Mars and Venus. Implications of these measurements on our understanding of the formation and evolution of the planets and satellite are discussed. Our current knowledge of the carbon, nitrogen and oxygen isotopic ratios in the atmospheres of these planets, as well as on Jupiter and Saturn, is also reviewed. We finally show what progress can be expected in the very near future due to some new ground-based instrumentation particularly well suited to such studies, and to forthcoming space missions. PMID:11539257

  8. Radial Velocity Detection of Extra-Solar Planetary Systems

    NASA Technical Reports Server (NTRS)

    Cochran, William D.

    1998-01-01

    The McDonald Observatory Planetary Search (MOPS) was designed to search for Jovian-mass planets in orbit around solar-type stars by making high-precision measurements of the Radial Velocity (RV) of a star, to attempt to detect the reflex orbital motion of the star around the star-planet barycenter. In our solar system, the velocity of the Sun around the Sun-Jupiter barycenter averages 12.3 m/ s. The MOPS survey started operation in September 1987, and searches 36 bright, nearby, solar-type dwarfs to 10 m/s precision. The survey was started using telluric O2 absorption lines as the velocity reference metric. Observations use the McDonald Observatory 2.7-m Harlan Smith Telescope coude spectrograph with the six-foot camera. This spectrograph configuration isolates a single order of the echelle grating on a Texas Instruments 800 x 800 CCD. The telluric line method gave us a routine radial velocity precision of about 15 m/s for stars down to about 5-th magnitude. However, the data obtained with this technique suffered from some source of long-term systematic errors, which was probably the intrinsic velocity variability of the terrestrial atmosphere, i.e. winds. In order to eliminate this systematic error and to improve our overall measurement precision, we installed a stabilized I2 gas absorption cell as the velocity metric for the MOPS in October 1990. In use at the telescope, the cell is placed directly in front of the spectrograph entrance slit, with starlight passing through the cell. The use of this sealed stabilized I2 cell removes potential problems with possible long-term drifts in the velocity metric. The survey now includes a sample of 36 nearby F, G, and K type stars of luminosity class V or IV-V.

  9. The Significance of the Sodium Detection in the Extrasolar Planet HD209458b Atmosphere

    E-print Network

    S. Seager

    2003-05-19

    The Hubble Space Telescope (HST) detection of an extrasolar planet atmosphere in 2001 was a landmark step forward for the characterization of extrasolar planets. HST detected the trace element sodium, via the neutral atomic resonance doublet at 593 nm, in the transiting extrasolar giant planet HD209458b. In this paper I discuss the significance of this first ever extrasolar planet atmosphere detection. I explain how the sodium measurement can be used as a constraint on HD209458b atmosphere models and review recent interpretations of the lower-than-expected sodium line strength.

  10. The role of planetary formation and evolution in shaping the composition of exoplanetary atmospheres

    NASA Astrophysics Data System (ADS)

    Turrini, D.; Nelson, R. P.; Barbieri, M.

    2014-07-01

    Over the last twenty years, the search for extrasolar planets has revealed the rich diversity of outcomes from the formation and evolution of planetary systems. In order to fully understand how these extrasolar planets came to be, however, the orbital and physical data we possess are not enough, and they need to be complemented with information about the composition of the exoplanets. Ground-based and space-based observations provided the first data on the atmospheric composition of a few extrasolar planets, but a larger and more detailed sample is required before we can fully take advantage of it. The primary goal of a dedicated space mission like the Exoplanet Characterization Observatory (EChO) proposal is to fill this gap and to expand the limited data we possess by performing a systematic survey of extrasolar planets. The full exploitation of the data that space-based and ground-based facilities will provide in the near future, however, requires knowledge about the sources and sinks of the chemical species and molecules that will be observed. Luckily, the study of the past history of the Solar System provides several indications about the effects of processes like migration, late accretion and secular impacts, and on the time they occur in the life of planetary systems. In this work we will review what is already known about the factors influencing the composition of planetary atmospheres, focusing on the case of gaseous giant planets, and what instead still need to be investigated.

  11. Water vapour in the atmosphere of a transiting extrasolar planet

    E-print Network

    Giovanna Tinetti; Alfred Vidal-Madjar; Mao-Chang Liang; Jean-Philippe Beaulieu; Yuk Yung; Sean Carey; Robert J. Barber; Jonathan Tennyson; Ignasi Ribas; Nicole Allard; Gilda E. Ballester; David K. Sing; Franck Selsis

    2007-07-20

    Water is predicted to be among, if not the most abundant molecular species after hydrogen in the atmospheres of close-in extrasolar giant planets (hot-Jupiters) Several attempts have been made to detect water on an exoplanet, but have failed to find compelling evidence for it or led to claims that should be taken with caution. Here we report an analysis of recent observations of the hot-Jupiter HD189733b taken during the transit, where the planet passed in front of its parent star. We find that absorption by water vapour is the most likely cause of the wavelength-dependent variations in the effective radius of the planet at the infrared wavelengths 3.6, 5.8 and 8 microns. The larger effective radius observed at visible wavelengths may be due to either star variability or the presence of clouds/hazes. We explain the most recent thermal infrared observations of the planet during secondary transit behind the star, reporting a non-detection of water on HD189733b, as being a consequence of the nearly isothermal vertical profile of the planet.s atmosphere. Our results show that water is detectable on extrasolar planets using the primary transit technique and that the infrared should be a better wavelength region than the visible, for such searches.

  12. PLANETARY MIGRATION AND ECCENTRICITY AND INCLINATION RESONANCES IN EXTRASOLAR PLANETARY SYSTEMS

    SciTech Connect

    Lee, Man Hoi [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Thommes, Edward W. [Department of Physics, University of Guelph, Guelph, ON N1G 2W1 (Canada)], E-mail: mhlee@hku.hk, E-mail: ethommes@physics.uoguelph.ca

    2009-09-10

    The differential migration of two planets due to planet-disk interaction can result in capture into the 2:1 eccentricity-type mean-motion resonances. Both the sequence of 2:1 eccentricity resonances that the system is driven through by continued migration and the possibility of a subsequent capture into the 4:2 inclination resonances are sensitive to the migration rate within the range expected for type II migration due to planet-disk interaction. If the migration rate is fast, the resonant pair can evolve into a family of 2:1 eccentricity resonances different from those found by Lee. This new family has outer orbital eccentricity e {sub 2} {approx}> 0.4-0.5, asymmetric librations of both eccentricity resonance variables, and orbits that intersect if they are exactly coplanar. Although this family exists for an inner-to-outer planet mass ratio m {sub 1}/m {sub 2} {approx}> 0.2, it is possible to evolve into this family by fast migration only for m {sub 1}/m {sub 2} {approx}> 2. Thommes and Lissauer have found that a capture into the 4:2 inclination resonances is possible only for m {sub 1}/m {sub 2} {approx}< 2. We show that this capture is also possible for m {sub 1}/m {sub 2} {approx}> 2 if the migration rate is slightly slower than that adopted by Thommes and Lissauer. There is significant theoretical uncertainty in both the sign and the magnitude of the net effect of planet-disk interaction on the orbital eccentricity of a planet. If the eccentricity is damped on a timescale comparable to or shorter than the migration timescale, e {sub 2} may not be able to reach the values needed to enter either the new 2:1 eccentricity resonances or the 4:2 inclination resonances. Thus, if future observations of extrasolar planetary systems were to reveal certain combinations of mass ratio and resonant configuration, they would place a constraint on the strength of eccentricity damping during migration, as well as on the rate of the migration itself.

  13. Predicting Planets in Known Extra-Solar Planetary Systems III: Forming Terrestrial Planets

    E-print Network

    Raymond, S N

    2004-01-01

    Recent results have shown that many of the known extrasolar planetary systems contain regions which are stable for both massless and massive test particles. We simulate the formation of terrestrial planets in four planetary systems: HD37124, HD38529, 55Cnc, and HD74156. In each case, Moon- to Mars-sized planetary embryos are placed in between the giant planets and evolved for 100 Myr. We find that no terrestrial planets form in HD37124 and HD74156, although in some cases 1-2 lone embryos will survive for 100 Myr. Planets form relatively easily in 55Cnc, with masses up to 0.6 Earth masses and in some cases substantial water contents. HD38529 is likely to support an asteroid belt but no terrestrial planets of significant mass.

  14. Planetary Formation: From The Earth And Moon To Extrasolar Planets

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    An overview of current theories of planetary growth, emphasizing the formation of habitable planets, 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. 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 if they become massive enough before the protoplanetary disk dissipates, then they are able to accumulate substantial amounts of gas. Specific issues to be discussed include: (1) how do giant planets influence the formation and habitability of terrestrial planets? (2) could a giant impact leading to lunar formation have occurred - 100 million years after the condensation of the oldest meteorites?

  15. Radial Velocity Detection of Extra-Solar Planetary Systems

    NASA Technical Reports Server (NTRS)

    Cochran, William D.

    2004-01-01

    This NASA Origins Program grant supported four closely related research programs at The University of Texas at Austin: 1) The McDonald Observatory Planetary Search (MOPS) Program, using the McDonald Observatory 2.7m Harlan Smith telescope and its 2dcoud6 spectrometer, 2) A high-precision radial-velocity survey of Hyades dwarfs, using the Keck telescope and its HIRES spectrograph, 3) A program at McDonald Observatory to obtain spectra of the parent stars of planetary systems at R = 210,000, and 4) the start of high precision radial velocity surveys using the Hobby-Eberly Telescope. The most important results from NASA support of these research programs are described below. A list of all papers published under support of this grant is included at the end.

  16. Radial Velocity Detection of Extra-Solar Planetary Systems

    NASA Technical Reports Server (NTRS)

    Cochran, William D.

    2004-01-01

    This NASA Origins Program grant supported four closely related research programs at The University of Texas at Austin: 1) The McDonald Observatory Planetary Search (MOPS) Program, using the McDonald Observatory 2.7m Harlan Smith telescope and its 2dcoude spectrometer, 2) A high-precision radial-velocity survey of Hyades dwarfs, using the Keck telescope and its HIRES spectrograph, 3) A program at McDonald Observatory to obtain spectra of the parent stars of planetary systems at R = 210,000, and 4) the start of high precision radial velocity surveys using the Hobby-Eberly Telescope. The most important results from NASA support of these research programs are described. A list of all papers published under support of this grant is included at the end.

  17. Radial velocity detection of extra-solar planetary systems

    NASA Technical Reports Server (NTRS)

    Cochran, William D.

    1991-01-01

    The goal of this program was to detect planetary systems in orbit around other stars through the ultra high precision measurement of the orbital motion of the star around the star-planet barycenter. The survey of 33 nearby solar-type stars is the essential first step in understanding the overall problem of planet formation. The program will accumulate the necessary statistics to determine the frequency of planet formation as a function of stellar mass, age, and composition.

  18. An extrasolar planetary system with three Neptune-mass planets

    E-print Network

    C. Lovis; M. Mayor; F. Pepe; Y. Alibert; W. Benz; F. Bouchy; A. C. M. Correia; J. Laskar; C. Mordasini; D. Queloz; N. C. Santos; S. Udry; J. -L. Bertaux; J. -P. Sivan

    2007-03-01

    Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 AU (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.

  19. The search for extra-solar planetary systems.

    PubMed

    Paresce, F

    1992-01-01

    I review the observational evidence for planetary systems around nearby stars and, using our own solar system as a guide, assess the stringent requirements that new searches need to meet in order to unambiguously establish the presence of another planetary system. Basically, these requirements are: 1 milliarcsecond or better positional accuracy for astrometric techniques, 9 orders of magnitude or better star to planet luminosity ratio discrimination at 0.5 to 1" separation in the optical for direct imaging techniques, 10 meters sec-1 or better radial velocity accuracy for reflex motion techniques and +/-1% or better brightness fluctuation accuracy for planet/star occultation measurements. The astrometric accuracy is in reach of HST, direct imaging will require much larger telescopes and/or a 50 times smoother mirror than HST while the reflex motion and occultation techniques best performed on the ground are just becoming viable and promise exciting new discoveries. On the other band, new indirect evidence on the existence of other planetary systems also comes from the observation of large dusty disks around nearby main sequence stars not too dissimilar from our sun. In one particular case, that of Beta Pictoris, a flattened disk seen nearly edge-on has been imaged in the optical and near IR down to almost 70 AU of the star. It probably represents a young planetary system in its clearing out phase as planetesimals collide, erode and are swept out of the inner system by radiation pressure. The hypothesized Kuiper belt around our solar system may be the analogous structure in a later evolutionary stage. Features of this type have been detected in the far IR and sub-millimeter wavelength regions around 50-100 nearby main sequence and pre-main sequence stars. I discuss a battery of new accurate observations planned in the near future of these objects some of which may actually harbour planets or planetesimals that will certainly dramatically improve our knowledge of planetary system formation processes and our peculiar position in this scheme. PMID:11538135

  20. IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS. III. BREAKDOWN CONDITIONS FOR MINERAL CLOUDS

    SciTech Connect

    Helling, Ch.; Jardine, M.; Stark, C. [SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Diver, D., E-mail: ch@leap2010.eu [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2013-04-20

    Electric discharges were detected directly in the cloudy atmospheres of Earth, Jupiter, and Saturn, are debatable for Venus, and indirectly inferred for Neptune and Uranus in our solar system. Sprites (and other types of transient luminous events) have been detected only on Earth, and are theoretically predicted for Jupiter, Saturn, and Venus. Cloud formation is a common phenomenon in ultra-cool atmospheres such as in brown dwarf and extrasolar planetary atmospheres. Cloud particles can be expected to carry considerable charges which may trigger discharge events via small-scale processes between individual cloud particles (intra-cloud discharges) or large-scale processes between clouds (inter-cloud discharges). We investigate electrostatic breakdown characteristics, like critical field strengths and critical charge densities per surface, to demonstrate under which conditions mineral clouds undergo electric discharge events which may trigger or be responsible for sporadic X-ray emission. We apply results from our kinetic dust cloud formation model that is part of the DRIFT-PHOENIX model atmosphere simulations. We present a first investigation of the dependence of the breakdown conditions in brown dwarf and giant gas exoplanets on the local gas-phase chemistry, the effective temperature, and primordial gas-phase metallicity. Our results suggest that different intra-cloud discharge processes dominate at different heights inside mineral clouds: local coronal (point discharges) and small-scale sparks at the bottom region of the cloud where the gas density is high, and flow discharges and large-scale sparks near, and maybe above, the cloud top. The comparison of the thermal degree of ionization and the number density of cloud particles allows us to suggest the efficiency with which discharges will occur in planetary atmospheres.

  1. Chemical kinetics on extrasolar planets.

    PubMed

    Moses, Julianne I

    2014-04-28

    Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures approximately <2000K, and in the uppermost atmosphere at any temperature, chemical kinetics matters. The two key mechanisms by which kinetic processes drive an exoplanet atmosphere out of equilibrium are photochemistry and transport-induced quenching. I review these disequilibrium processes in detail, discuss observational consequences and examine some of the current evidence for kinetic processes on extrasolar planets. PMID:24664912

  2. Predicting Planets in Known Extra-Solar Planetary Systems I: Test Particle Simulations

    E-print Network

    Rory Barnes; Sean N. Raymond

    2004-02-25

    Recent work has suggested that many planetary systems lie near instability. If all systems are near instability, an additional planet must exist in stable regions of well-separated extra-solar planetary systems to push these systems to the edge of stability. We examine the known systems by placing massless test particles in between the planets and integrating for 1-10 million years. We find that some systems, HD168443 and HD74156, eject nearly all test particles within 2 million years. However we find that HD37124, HD38529, and 55Cnc have large contiguous regions in which particles survive for 10 million years. These three systems, therefore, seem the most likely candidates for additional companions. Furthermore HD74156 and HD168443 must be complete and therefore radial velocity surveys should only focus on detecting more distant companions. We also find that several systems show stable regions that only exist at nonzero eccentricities.

  3. Terrestrial Planet Formation in Extra-Solar Planetary Systems

    E-print Network

    Raymond, Sean N

    2008-01-01

    Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called "planetary embryos". Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass an...

  4. The photochemistry of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Dalgarno, A.

    1988-01-01

    Recent theoretical and observational investigations of photochemical processes in the atmospheres of the planets and their satellites are reviewed. Particular attention is given to the CO2-dominated atmospheres of Mars and Venus, the hydrogen-dominated atmospheres of the Jovian planets, the SO2 atmosphere of Io, and the massive atmospheres of Titan and Triton. The principal reaction paths involved are listed and briefly characterized, and numerical data on atmospheric compositions are given in tables.

  5. Spin of Planetary Probes in Atmospheric Flight

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    Probes that enter planetary atmospheres are often spun during entry or descent for a variety of reasons. Their spin rate histories are influenced by often subtle effects. The spin requirements, control methods and flight experience from planetary and earth entry missions are reviewed. An interaction of the probe aerodynamic wake with a drogue parachute, observed in Gemini wind tunnel tests, is discussed in connection with the anomalous spin behaviour of the Huygens probe.

  6. Application of MODTRAN to Planetary Atmospheres

    Microsoft Academic Search

    L. Bernstein; R. Sundberg; A. Singer-Berk

    2007-01-01

    MODTRAN(TM) is a widely used radiative-transfer (RT) code for computing the transmission, emission and scattering in the Earth's atmosphere. However, the RT algorithms used in MODTRAN(TM) are generally applicable to any layered atmosphere, and, in principle, can be applied to any planetary atmosphere. The primary required modification required for this application is the development of the appropriate spectral properties data

  7. Detection techniques for tenuous planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hoenig, S. A. (principal investigator)

    1975-01-01

    Electrostatic charging of dust and its effect on planetary atmospheres is discussed, along with its applications to Martian atmosphere. Laboratory and field experiments in dust storms indicate that the major atmospheric parameters on Mars include: (1) pressure, temperature, and relative humidity; (2) wind velocity and direction; (3) particulate size and composition; and (4) electrostatic charge and field gradient. Various instrumentation techniques adapted for a Mars Lander are briefly reviewed. The effect of exoelectron emission on surface catalysis is studied.

  8. Review of methodology and technology available for the detection of extrasolar planetary systems.

    PubMed

    Tarter, J C; Black, D C; Billingham, J

    1986-01-01

    Anyone undertaking an interstellar voyage might wish to be assured of the existence of a safe planetary harbor at the other end! Aside from the obvious interest of the participants in this Symposium, astronomers and astrophysicists are also eager to detect and study other planetary systems in order to better understand the formation of our own Solar System. Scientists involved in the search for extraterrestrial intelligence argue that planets suitable for the evolution of life may abound elsewhere within our own Milky Way Galaxy. On theoretical grounds, they are probably correct, but they lack any observational support. For in spite of decades of claimed astrometric detections of planetary companions and the recent exciting and tantalizing observations from the IRAS satellite and the IR speckle observations of Van Biesbroeck 8 and other cool stars, there is no unambiguous proof for the existence of another planetary system beyond our own. In this paper we review the various methods for detecting extrasolar planets and briefly describe the Earth and space based technology currently available and discuss the near-term plans to implement these different search techniques. In each case an attempt is made to identify the limiting source of systematic error inherent to the methodology and to assess the potential for technological improvements. PMID:11539063

  9. Toward a Deterministic Model of Planetary Formation. I. A Desert in the Mass and Semimajor Axis Distributions of Extrasolar Planets

    Microsoft Academic Search

    S. Ida; D. N. C. Lin

    2004-01-01

    In an attempt to develop a deterministic theory for planet formation, we examine the accretion of cores of giant planets from planetesimals, gas accretion onto the cores, and their orbital migration. We adopt a working model for nascent protostellar disks with a wide variety of surface density distributions in order to explore the range of diversity among extrasolar planetary systems.

  10. ROCKY EXTRASOLAR PLANETARY COMPOSITIONS DERIVED FROM EXTERNALLY POLLUTED WHITE DWARFS

    SciTech Connect

    Klein, B.; Jura, M.; Zuckerman, B. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562 (United States); Koester, D., E-mail: kleinb@astro.ucla.edu, E-mail: jura@astro.ucla.edu, E-mail: ben@astro.ucla.edu, E-mail: koester@astrophysik.uni-kiel.de [Institut fuer Theoretische Physik und Astrophysik, University of Kiel, D-24098 Kiel (Germany)

    2011-11-01

    We report Keck High Resolution Echelle Spectrometer data and model atmosphere analysis of two helium-dominated white dwarfs, PG1225-079 and HS2253+8023, whose heavy pollutions most likely derive from the accretion of terrestrial-type planet(esimal)s. For each system, the minimum accreted mass is {approx}10{sup 22} g, that of a large asteroid. In PG1225-079, Mg, Cr, Mn, Fe, and Ni have abundance ratios similar to bulk Earth values, while we measure four refractory elements, Ca, Sc, Ti, and V, all at a factor of {approx}2-3 higher abundance than in the bulk Earth. For HS2253+8023 the swallowed material was compositionally similar to bulk Earth in being more than 85% by mass in the major element species, O, Mg, Si, and Fe, and with abundances in the distinctive proportions of mineral oxides-compelling evidence for an origin in a rocky parent body. Including previous studies we now know of four heavily polluted white dwarfs where the measured oxygen and hydrogen are consistent with the view that the parents' bodies formed with little ice, interior to any snow line in their nebular environments. The growing handful of polluted white dwarf systems with comprehensive abundance measurements form a baseline for characterizing rocky exoplanet compositions that can be compared with bulk Earth.

  11. The presence of methane in the atmosphere of an extrasolar planet

    Microsoft Academic Search

    Mark R. Swain; Gautam Vasisht; Giovanna Tinetti

    2008-01-01

    Molecules present in the atmospheres of extrasolar planets are expected to influence strongly the balance of atmospheric radiation, to trace dynamical and chemical processes, and to indicate the presence of disequilibrium effects. As molecules have the potential to reveal atmospheric conditions and chemistry, searching for them is a high priority. The rotational-vibrational transition bands of water, carbon monoxide and methane

  12. Faculty Positions Department of Earth, Atmospheric, and Planetary Sciences

    E-print Network

    Kihara, Daisuke

    Faculty Positions Department of Earth, Atmospheric, and Planetary Sciences Purdue University In support of its significant existing strengths in climate and extreme weather, the Department of Earth, Atmospheric and Planetary Sciences (EAPS), within the College of Science, Purdue University, invites

  13. Chemical kinetics and modeling of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Yung, Yuk L.

    1990-01-01

    A unified overview is presented for chemical kinetics and chemical modeling in planetary atmospheres. The recent major advances in the understanding of the chemistry of the terrestrial atmosphere make the study of planets more interesting and relevant. A deeper understanding suggests that the important chemical cycles have a universal character that connects the different planets and ultimately link together the origin and evolution of the solar system. The completeness (or incompleteness) of the data base for chemical kinetics in planetary atmospheres will always be judged by comparison with that for the terrestrial atmosphere. In the latter case, the chemistry of H, O, N, and Cl species is well understood. S chemistry is poorly understood. In the atmospheres of Jovian planets and Titan, the C-H chemistry of simple species (containing 2 or less C atoms) is fairly well understood. The chemistry of higher hydrocarbons and the C-N, P-N chemistry is much less understood. In the atmosphere of Venus, the dominant chemistry is that of chlorine and sulfur, and very little is known about C1-S coupled chemistry. A new frontier for chemical kinetics both in the Earth and planetary atmospheres is the study of heterogeneous reactions. The formation of the ozone hole on Earth, the ubiquitous photochemical haze on Venus and in the Jovian planets and Titan all testify to the importance of heterogeneous reactions. It remains a challenge to connect the gas phase chemistry to the production of aerosols.

  14. PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS

    SciTech Connect

    Raymond, Sean N. [Universite de Bordeaux, Observatoire Aquitain des Sciences de l'Univers, 2 rue de l'Observatoire, BP 89, F-33271 Floirac Cedex (France); Armitage, Philip J. [JILA, University of Colorado, Boulder, CO 80309 (United States); Gorelick, Noel, E-mail: pja@jilau1.colorado.ed [Google, Inc., 1600 Amphitheatre Parkway, Mountain View, CA 94043 (United States)

    2010-03-10

    We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ('planetesimals'). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M{sub +} from 10 to 20 AU. For large planet masses (M {approx}> M{sub Sat}), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a {approx}< 3 AU) is consistent with isolated planet-planet scattering. We explain the observed mass dependence-which is in the opposite sense from that predicted by the simplest scattering models-as a consequence of strong correlations between planet masses in the same system. At somewhat larger radii, initial planetary mass correlations and disk effects can yield similar modest changes to the eccentricity distribution. Nonetheless, strong damping of eccentricity for low-mass planets at large radii appears to be a secure signature of the dynamical influence of disks. Radial velocity measurements capable of detecting planets with K {approx} 5 m s{sup -1} and periods in excess of 10 years will provide constraints on this regime. Finally, we present an analysis of the predicted separation of planets in two-planet systems, and of the population of planets in mean-motion resonances (MMRs). We show that, if there are systems with {approx} Jupiter-mass planets that avoid close encounters, the planetesimal disk acts as a damping mechanism and populates MMRs at a very high rate (50%-80%). In many cases, resonant chains (in particular the 4:2:1 Laplace resonance) are set up among all three planets. We expect such resonant chains to be common among massive planets in outer planetary systems.

  15. Planet-Planet Scattering in Planetesimal Disks. II. Predictions for Outer Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

    2010-03-01

    We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ("planetesimals"). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M ? from 10 to 20 AU. For large planet masses (M >~ M Sat), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a <~ 3 AU) is consistent with isolated planet-planet scattering. We explain the observed mass dependence—which is in the opposite sense from that predicted by the simplest scattering models—as a consequence of strong correlations between planet masses in the same system. At somewhat larger radii, initial planetary mass correlations and disk effects can yield similar modest changes to the eccentricity distribution. Nonetheless, strong damping of eccentricity for low-mass planets at large radii appears to be a secure signature of the dynamical influence of disks. Radial velocity measurements capable of detecting planets with K ? 5 m s-1 and periods in excess of 10 years will provide constraints on this regime. Finally, we present an analysis of the predicted separation of planets in two-planet systems, and of the population of planets in mean-motion resonances (MMRs). We show that, if there are systems with ~ Jupiter-mass planets that avoid close encounters, the planetesimal disk acts as a damping mechanism and populates MMRs at a very high rate (50%-80%). In many cases, resonant chains (in particular the 4:2:1 Laplace resonance) are set up among all three planets. We expect such resonant chains to be common among massive planets in outer planetary systems.

  16. Convective storms in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sánchez-Lavega, A.

    2013-05-01

    The atmospheres of the planets in the Solar System have different physical properties that in some cases can be considered as extreme when compared with our own planet's more familiar atmosphere. From the tenuous and cold atmosphere of Mars to the dense and warm atmosphere of Venus in the case of the terrestrial planets, to the gigantic atmospheres of the outer planets, or the nitrogen and methane atmosphere of Saturn's moon Titan, we can find a large variety of physical environments. The comparative study of these atmospheres provides a better understanding of the physics of a geophysical fluid. In many of these worlds convective storms of different intensity appear. They are analogous to terrestrial atmospheres fed by the release of latent heat when one of the gases in the atmosphere condenses and they are therefore called moist convective storms. In many of these planets they can produce severe meteorological phenomena and by studying them in a comparative way we can aspire to get a further insight in the dynamics of these atmospheres even beyond the scope of moist convection. A classical example is the structure of the complex systems of winds in the giant planets Jupiter and Saturn. These winds are zonal and alternate in latitude but their deep structure is not accessible to direct observation. However the behaviour of large--scale convective storms vertically extending over the "weather layer" allows to study the buried roots of these winds. Another interesting atmosphere with a rather different structure of convection is Titan, a world where methane is close to its triple point in the atmosphere and can condense in bright clouds with large precipitation fluxes that may model part of the orography of the surface making Titan a world with a methane cycle similar to the hydrological cycle of Earth's atmosphere.

  17. Predicting Planets in Known Extra-Solar Planetary Systems III: Forming Terrestrial Planets

    E-print Network

    Sean N. Raymond; Rory Barnes; Nathan A. Kaib

    2006-05-15

    Recent results have shown that many of the known extrasolar planetary systems contain regions which are stable for both Earth-mass and Saturn-mass planets. Here we simulate the formation of terrestrial planets in four planetary systems -- 55 Cancri, HD 38529, HD 37124, and HD 74156 -- under the assumption that these systems of giant planets are complete and that their orbits are well-determined. Assuming the giant planets formed and migrated quickly, then terrestrial planets may form from a second generation of planetesimals. In each case, Moon- to Mars-sized planetary embryos are placed in between the giant planets and evolved for 100 Myr. We find that planets form relatively easily in 55 Cnc, with masses up to 0.6 Earth masses and in some cases substantial water contents and orbits in the habitable zone. HD 38529 is likely to support an asteroid belt but no terrestrial planets of significant mass. No terrestrial planets form in HD 37124 and HD 74156, although in some cases 1-2 lone embryos survive for 100 Myr. If migration occurred later, depleting the planetesimal disk, then massive terrestrial planets are unlikely to form in any of these systems.

  18. Detection techniques for tenuous planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hoenig, S. A.

    1972-01-01

    The research for the development of new types of detectors for analysis of planetary atmospheres is summarized. Topics discussed include: corona discharge humidity detector, surface catalysis and exo-electron emission, and analysis of soil samples by means of exo-electron emission. A report on the exo-electron emission during heterogeneous catalysis is included.

  19. The Role of Clouds in Brown Dwarf and Extrasolar Giant Planet Atmospheres

    E-print Network

    M. S. Marley; A. S. Ackerman

    2001-03-16

    Clouds and hazes are important throughout our solar system and in the atmospheres of brown dwarfs and extrasolar giant planets. Among the brown dwarfs, clouds control the colors and spectra of the L-dwarfs; the disappearance of clouds helps herald the arrival of the T-dwarfs. The structure and composition of clouds will be among the first remote-sensing results from the direct detection of extrasolar giant planets.

  20. Atmospheric planetary wave response to external forcing

    NASA Technical Reports Server (NTRS)

    Stevens, D. E.; Reiter, E. R.

    1985-01-01

    The tools of observational analysis, complex general circulation modeling, and simpler modeling approaches were combined in order to attack problems on the largest spatial scales of the earth's atmosphere. Two different models were developed and applied. The first is a two level, global spectral model which was designed primarily to test the effects of north-south sea surface temperature anomaly (SSTA) gradients between the equatorial and midlatitude north Pacific. The model is nonlinear, contains both radiation and a moisture budget with associated precipitation and surface evaporation, and utilizes a linear balance dynamical framework. Supporting observational analysis of atmospheric planetary waves is briefly summarized. More extensive general circulation models have also been used to consider the problem of the atmosphere's response, especially in the horizontal propagation of planetary scale waves, to SSTA.

  1. Detection techniques for tenuous planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hoenig, S. A.

    1978-01-01

    The application of detectors developed for analysis of planetary atmospheres under partial vacuum conditions, and data obtained during dust charging studies to various industrial problems is summarized. A specialized apparatus for dust measurements on a planetary lander was designed with the capability of measuring ambient dust density as a function of particle size, as well as for observing the charge of the collected dust. the optical system operates on an intermittent basis and requires only low power. No radioactive source or delicate detection equipment is required. Advances in monitoring catalyst operation by means of exoelection emission are also reported.

  2. Signatures of hot hydrogen in the atmosphere of the extrasolar planet HD209458b

    Microsoft Academic Search

    David Sing; G. Ballester; Floyd Herbert

    2007-01-01

    Of the extrasolar planets detected so far, about 10% consist of giant planets which orbit very close to their parent stars. The atmospheres of these ``hot-Jupiters'' are largely heated by the immense stellar irradiation. In the case of the planet HD209458b, this energy deposition results in a hydrodynamic state in the upper atmosphere, allowing for sizable expansion and escape of

  3. Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets

    E-print Network

    Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets Matthias bang nucleosynthesis, the chemical evolution of the Galaxy, mixing processes in stellar interiors Steffen and Elisabetta Caffau Sternphysik In metal-poor stellar atmospheres, the Lithium line at 6707 Ã?

  4. Studies of Tenuous Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Combi, Michael R.

    1998-01-01

    The final report includes an overall project overview as well as scientific background summaries of dust and sodium in comets, and tenuous atmospheres of Jupiter's natural satellites. Progress and continuing work related to dust coma and tenuous atmospheric studies are presented. Also included are published articles written during the course of the report period. These are entitled: (1) On Europa's Magnetospheric Interaction: An MHD Simulation; (2) Dust-Gas Interrelations in Comets: Observations and Theory; and (3) Io's Plasma Environment During the Galileo Flyby: Global Three Dimensional MHD Modeling with Adaptive Mesh Refinement.

  5. Photochemistry of planetary atmospheres. [Mars atmospheric composition

    NASA Technical Reports Server (NTRS)

    Stief, L. J.

    1973-01-01

    The atmospheric composition of Mars is presented, and the applicability of laboratory data on CO2 absorption cross sections and quantum yields of dissociation is discussed. A summary and critical evaluation are presented on the various mechanisms proposed for converting the photodissociation products CO and O2 back to CO2.

  6. Ionization in Atmospheres of Brown Dwarfs and Extrasolar Planets VI: Properties of Large-scale Discharge Events

    NASA Astrophysics Data System (ADS)

    Bailey, R. L.; Helling, Ch.; Hodosán, G.; Bilger, C.; Stark, C. R.

    2014-03-01

    Mineral clouds in substellar atmospheres play a special role as a catalyst for a variety of charge processes. If clouds are charged, the surrounding environment becomes electrically activated, and ensembles of charged grains are electrically discharging (e.g., by lightning), which significantly influences the local chemistry creating conditions similar to those thought responsible for life in early planetary atmospheres. We note that such lightning discharges contribute also to the ionization state of the atmosphere. We apply scaling laws for electrical discharge processes from laboratory measurements and numerical experiments to DRIFT-PHOENIX model atmosphere results to model the discharge's propagation downward (as lightning) and upward (as sprites) through the atmospheric clouds. We evaluate the spatial extent and energetics of lightning discharges. The atmospheric volume affected (e.g., by increase of temperature or electron number) is larger in a brown dwarf atmosphere (108-1010 m3) than in a giant gas planet (104-106 m3). Our results suggest that the total dissipated energy in one event is <1012 J for all models of initial solar metallicity. First attempts to show the influence of lightning on the local gas phase indicate an increase of small carbohydrate molecules like CH and CH2 at the expense of CO and CH4. Dust-forming molecules are destroyed and the cloud particle properties are frozen in unless enough time is available for complete evaporation. We summarize instruments potentially suitable to observe lightning on extrasolar objects.

  7. Planetary atmospheric physics and solar physics research

    NASA Technical Reports Server (NTRS)

    1973-01-01

    An overview is presented on current and planned research activities in the major areas of solar physics, planetary atmospheres, and space astronomy. The approach to these unsolved problems involves experimental techniques, theoretical analysis, and the use of computers to analyze the data from space experiments. The point is made that the research program is characterized by each activity interacting with the other activities in the laboratory.

  8. Origin and evolution of planetary and satellite atmospheres

    SciTech Connect

    Atreya, S.K.; Pollack, J.B.; Matthews, M.S.

    1989-01-01

    The present volume on the origin and evolution of planet and satellite atmospheres discusses the chemistry of interstellar gas and grains, planetary accretion, cometary composition, the inventories of asteroid volatiles, key similarities and differences among the terrestrial planets' atmospheric compositions, and planets' atmospheric escape and water loss. Also discussed are planetary atmosphere-planetary interior evolutionary coupling, the atmospheric composition of the outer planets, the structure and composition of giant planet interiors, the tenuous atmosphere of Io, the sources of the atmospheres of the outer solar system's satellites, the present state and chemical evolution of the Titan, Triton, and Pluto atmospheres, and the thermal structure and heat balance of the outer planets.

  9. Origin and evolution of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Lewis, John S.

    1992-01-01

    This report concerns several research tasks related to the origin and evolution of planetary atmospheres and the large-scale distribution of volatile elements in the Solar System. These tasks and their present status are as follows: (1) we have conducted an analysis of the volatility and condensation behavior of compounds of iron, aluminum, and phosphorus in the atmosphere of Venus in response to publish interpretations of the Soviet Venera probe XRF experiment data, to investigate the chemistry of volcanic gases, injection of volatiles by cometary and asteroidal impactors, and reactions in the troposphere; (2) we have completed and are now writing up our research on condensation-accretion modeling of the terrestrial planets; (3) we have laid the groundwork for a detailed study of the effects of water transport in the solar nebula on the bulk composition, oxidation state, and volatile content of preplanetary solids; (4) we have completed an extensive laboratory study of cryovolcanic materials in the outer solar system; (5) we have begun to study the impact erosion and shock alteration of the atmosphere of Mars resulting from cometary and asteroidal bombardment; and (6) we have developed a new Monte Carlo model of the cometary and asteroidal bombardment flux on the terrestrial planets, including all relevant chemical and physical processes associated with atmospheric entry and impact, to assess both the hazards posed by this bombardment to life on Earth and the degree of cross-correlation between the various phenomena (NO(x) production, explosive yield, crater production, iridium signature, etc.) that characterize this bombardment. The purpose of these investigations has been to contribute to the developing understanding of both the dynamics of long-term planetary atmosphere evolution and the short-term stability of planetary surface environments.

  10. Relativistic breakdown in planetary atmospheres

    SciTech Connect

    Dwyer, J. R. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, Florida 32901 (United States)

    2007-04-15

    In 2003, a new electrical breakdown mechanism involving the production of runaway avalanches by positive feedback from runaway positrons and energetic photons was introduced. This mechanism, which shall be referred to as 'relativistic feedback', allows runaway discharges in gases to become self-sustaining, dramatically increasing the flux of runaway electrons, the accompanying high-energy radiation, and resulting ionization. Using detailed Monte Carlo calculations, properties of relativistic feedback are investigated. It is found that once relativistic feedback fully commences, electrical breakdown will occur and the ambient electric field, extending over cubic kilometers, will be discharged in as little as 2x10{sup -5} s. Furthermore, it is found that the flux of energetic electrons and x rays generated by this mechanism can exceed the flux generated by the standard relativistic runaway electron model by a factor of 10{sup 13}, making relativistic feedback a good candidate for explaining terrestrial gamma-ray flashes and other high-energy phenomena observed in the Earth's atmosphere.

  11. Diurnal Forcing of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Houben, Howard C.

    1997-01-01

    Much progress has been made on calculations of the Martian seasonal water cycle using the Mars Climate Model developed for this purpose. Two papers, documenting the model and the water transport results obtained with it have been published in the Journal of Geophysical Research - Planets. An additional paper describing results related to the evolution of the seasonal water cycle as a result of orbital changes was published in Advances in Space Research. Since that time, further studies have concentrated on the consequences of the soil adsorption required to match the observed water cycle and its relation to the stability of ground ice and other potential water reservoirs. Earth-related studies have concentrated on incorporating an efficient and realistic microphysical model into the Ames Stratospheric General Circulation Model used to simulate the spread of the ML Pinatubo and other volcanic clouds in the stratosphere. In addition, visualizations of the simulations are being incorporated into a video describing the UARS mission. A paper describing the new stratospheric aerosol microphysics package (and its consequences for volcanic cloud evolution) will be submitted in the near future. The paper will discuss the relative importance of condensation and coagulation to early particle growth and the separation of the cloud by sedimentation of the larger particles. A more general paper which highlights the observation that particle number densities did not increase dramatically after the ML Pinatubo eruption is planned. Simulations of atmospheric transport will be extended to include studies of terrestrial tropospheric tracers using the Fifth-Generation Penn State/NCAR Mesoscale Model.

  12. Purdue University Department of Earth, Atmospheric, and Planetary Sciences

    E-print Network

    Kihara, Daisuke

    Purdue University Department of Earth, Atmospheric, and Planetary Sciences Visiting Assistant Professor The Department of Earth, Atmospheric, and Planetary Sciences at Purdue University seeks a visiting. Applicants should have a Ph.D. in atmospheric or related sciences. The successful candidate will teach

  13. Chemical Equilibrium Abundances in Brown Dwarf and Extrasolar Giant Planet Atmospheres

    Microsoft Academic Search

    Adam Burrows; C. M. Sharp

    1999-01-01

    We explore detailed chemical equilibrium abundance profiles for a variety of brown dwarf and extrasolar giant planet atmosphere models, focusing in particular on Gl 229B, and derive the systematics of the changes in the dominant reservoirs of the major elements with altitude and temperature. We assume an Anders & Grevesse solar composition of 27 chemical elements and track 330 gas-phase

  14. Predicting Planets in Known Extra-Solar Planetary Systems II: Testing for Saturn-mass Planets

    E-print Network

    Sean N. Raymond; Rory Barnes

    2004-04-09

    Recent results have shown that many of the known extrasolar planetary systems contain regions which are stable for massless test particles. We examine the possibility that Saturn-mass planets exist in these systems, just below the detection threshold, and attempt to predict likely orbital parameters for such unseen planets. To do this, we insert a Saturn-mass planet into the stable regions of these systems and integrate its orbit for 100 million years. We conduct 200-600 of these experiments to test parameter space in HD37124, HD38529, 55Cnc, and HD74156. In HD37124 the global maximum of the survival rate of Saturns in parameter space is at semimajor axis a = 1.03 AU, eccentricity e=0.1. In HD38529, only 5% of Saturns are unstable, and the region in which a Saturn could survive is very broad, centered on 0.5

  15. Thorium Abundances in Solar Twins and Analogs: Implications for the Habitability of Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Unterborn, Cayman T.; Johnson, Jennifer A.; Panero, Wendy R.

    2015-06-01

    We present the first investigation of Th abundances in solar twins and analogues to understand the possible range of this radioactive element and its effect on rocky planet interior dynamics and potential habitability. The abundances of the radioactive elements Th and U are key components of a planet’s energy budget, making up 30%–50% of the Earth’s. Radiogenic heat drives interior mantle convection and surface plate tectonics, which sustains a deep carbon and water cycle and thereby aides in creating Earth’s habitable surface. Unlike other heat sources that are dependent on the planet’s specific formation history, the radiogenic heat budget is directly related to the mantle concentration of these nuclides. As a refractory element, the stellar abundance of Th is faithfully reflected in the terrestrial planet’s concentration. We find that log {{? }Th} varies from 59% to 251% that of solar, suggesting extrasolar planetary systems may possess a greater energy budget with which to support surface to interior dynamics and thus increase their likelihood to be habitable compared to our solar system.

  16. Updated Review of Planetary Atmospheric Electricity

    NASA Astrophysics Data System (ADS)

    Yair, Y.; Fischer, G.; Simões, F.; Renno, N.; Zarka, P.

    2008-06-01

    This paper reviews the progress achieved in planetary atmospheric electricity, with focus on lightning observations by present operational spacecraft, aiming to fill the hiatus from the latest review published by Desch et al. (Rep. Prog. Phys. 65:955 997, 2002). The information is organized according to solid surface bodies (Earth, Venus, Mars and Titan) and gaseous planets (Jupiter, Saturn, Uranus and Neptune), and each section presents the latest results from space-based and ground-based observations as well as laboratory experiments. Finally, we review planned future space missions to Earth and other planets that will address some of the existing gaps in our knowledge.

  17. Updated Review of Planetary Atmospheric Electricity

    NASA Astrophysics Data System (ADS)

    Yair, Y.; Fischer, G.; Simões, F.; Renno, N.; Zarka, P.

    This paper reviews the progress achieved in planetary atmospheric electricity, with focus on lightning observations by present operational spacecraft, aiming to fill the hiatus from the latest review published by Desch et al. (Rep. Prog. Phys. 65:955-997, 2002). The information is organized according to solid surface bodies (Earth, Venus, Mars and Titan) and gaseous planets (Jupiter, Saturn, Uranus and Neptune), and each section presents the latest results from space-based and ground-based observations as well as laboratory experiments. Finally, we review planned future space missions to Earth and other planets that will address some of the existing gaps in our knowledge.

  18. Reflected Spectra and Albedos of Extrasolar Giant Planets. I. Clear and Cloudy Atmospheres

    Microsoft Academic Search

    Mark S. Marley; Christopher Gelino; Denise Stephens; Jonathan I. Lunine; Richard Freedman

    1999-01-01

    The reflected spectra of extrasolar giant planets are primarily influenced by Rayleigh scattering, molecular absorption, and atmospheric condensates. We present model geometric albedo and phase-integral spectra and Bond albedos for planets and brown dwarfs with masses between 0.8 and 70 Jupiter masses. Rayleigh scattering predominates in the blue while molecular absorption removes most red and infrared photons. Thus cloud-free atmospheres,

  19. Cryptic photosynthesis--extrasolar planetary oxygen without a surface biological signature.

    PubMed

    Cockell, Charles S; Kaltenegger, Lisa; Raven, John A

    2009-09-01

    On Earth, photosynthetic organisms are responsible for the production of virtually all the oxygen in the atmosphere. On land, vegetation reflects in the visible and leads to a "red edge," which developed about 450 million years ago on Earth and has been proposed as a biosignature for life on extrasolar planets. However, in many regions on Earth, particularly where surface conditions are extreme--in hot and cold deserts, for example--photosynthetic organisms can be driven into and under substrates where light is still sufficient for photosynthesis. These communities exhibit no detectable surface spectral signature to indicate life. The same is true of the assemblages of photosynthetic organisms at more than a few meters' depth in water bodies. These communities are widespread and dominate local photosynthetic productivity. We review known cryptic photosynthetic communities and their productivity. We have linked geomicrobiology with observational astronomy by calculating the disk-averaged spectra of cryptic habitats and identifying detectable features on an exoplanet dominated by such a biota. The hypothetical cryptic photosynthesis worlds discussed here are Earth analogues that show detectable atmospheric biosignatures like our own planet but do not exhibit a discernable biological surface feature in the disc-averaged spectrum. PMID:19778274

  20. Search for Double Transit Extrasolar Planetary Systems: Another Transiting Planet Around OGLE-TR-111 or a False Positive Detection?

    E-print Network

    Dante Minniti

    2005-01-20

    The search for double transit planetary systems opens new possibilities for the transit searches and for studies of orbital stability, stellar irradiation, and migration scenarios, among others. We explore the OGLE lightcurves of stars with confirmed planetary companions (OGLE-TR-10, OGLE-TR-56, OGLE-TR-111, OGLE-TR-113, and OGLE-TR-132), searching for additional transits. The most promising candidate is OGLE-TR-111, where the photometric measurements and the radial velocities are consistent with the presence of a second planet. If confirmed, OGLE-TR-111 would be the first extrasolar planetary system detected by transits. The parameters of the possible new planet OGLE-TR-111c would be: period P = 16.0644 d, semimajor axis a = 0.12 AU, orbital inclination i = 88-89 deg, mass M = 0.7 M_J, radius R = 0.85 R_J, density \\rho = 1.4 g/cm^3. If confirmed, OGLE-TR-111c would be the smallest and densest extrasolar planet measured todate, truly a Jovian planet, with properties intermediate between Jupiter and Saturn, albeit with shorter period. Additional photometric and spectroscopic data would allow to discriminate between a second transiting planet around OGLE-TR-111 and a false positive detection.

  1. Models of Polarized Light from Oceans and Atmospheres of Earth-like Extrasolar Planets

    E-print Network

    P. R. McCullough

    2006-10-17

    Specularly reflected light, or glint, from an ocean surface may provide a useful observational tool for studying extrasolar terrestrial planets. Detection of sea-surface glints would differentiate ocean-bearing terrestrial planets, i.e. those similar to Earth, from other terrestrial extrasolar planets. The brightness and degree of polarization of both sea-surface glints and atmospheric Rayleigh scattering are strong functions of the phase angle of the extrasolar planet. We modify analytic expressions for the bi-directional reflectances previously validated by satellite imagery of the Earth to account for the fractional linear polarization of sea-surface reflections and of Rayleigh scattering in the atmosphere. We compare our models with Earth's total visual light and degree of linear polarization as observed in the ashen light of the Moon, or Earthshine. We predict the spatially-integrated reflected light and its degree of polarization as functions of the diurnal cycle and orbital phase of Earth and Earth-like planets of various imagined types. The difference in polarized reflectances of Earth-like planets may increase greatly the detectability of such planets in the glare of their host star. Finally, sea-surface glints potentially may provide a practical means to map the boundaries between oceans and continents on extrasolar planets.

  2. A spectrum of an extrasolar planet

    Microsoft Academic Search

    L. Jeremy Richardson; Drake Deming; Karen Horning; Sara Seager; Joseph Harrington

    2007-01-01

    Of the over 200 known extrasolar planets, 14 exhibit transits in front of their parent stars as seen from Earth. Spectroscopic observations of the transiting planets can probe the physical conditions of their atmospheres. One such technique can be used to derive the planetary spectrum by subtracting the stellar spectrum measured during eclipse (planet hidden behind star) from the combined-light

  3. Extrasolar Giant Planets under Strong Stellar Irradiation

    Microsoft Academic Search

    S. Seager; D. D. Sasselov

    1998-01-01

    We investigate irradiation of extrasolar giant planets (EGPs) by treating the radiative transfer in detail, so that the flux from the parent star interacts with all relevant depths of the planetary atmosphere with no need for a preassumed albedo. Rayleigh scattering (in dust-free models) increases the EGP's flux by orders of magnitude shortward of the Ca II H and K

  4. University of Oxford: Atmospheric, Oceanic, and Planetary Physics

    NSDL National Science Digital Library

    The University of Oxford's Atmospheric, Oceanic, and Planetary Physics group "focuses on the study of physical processes in the atmospheres and oceans of the Earth and other planets, using experimental and theoretical techniques." Users can discover the group's innumerable projects and research tools in the areas involving the development of instruments and carrying out experiments mostly on satellites; analyses of data; and modeling and theoretical work related primarily to climate change, the middle atmosphere, planetary atmospheres, and to laboratory experiments on fluids. Individuals can find informational materials about its facilities and capabilities. The website answers a host of questions related to climate change, the ozone, and planetary phenomena.

  5. IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS. I. THE ROLE OF ELECTRON AVALANCHE

    SciTech Connect

    Helling, Ch.; Jardine, M. [SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Witte, S. [Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg (Germany); Diver, D. A., E-mail: ch80@st-andrews.ac.uk [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2011-01-20

    Brown dwarf and extrasolar planet atmospheres form clouds which strongly influence the local chemistry and physics. These clouds are globally neutral obeying dust-gas charge equilibrium which is, on short timescales, inconsistent with the observation of stochastic ionization events of the solar system planets. We argue that a significant volume of the clouds in brown dwarfs and extrasolar planets is susceptible to local discharge events. These are electron avalanches triggered by charged dust grains. Such intra-cloud discharges occur on timescales shorter than the time needed to neutralize the dust grains by collisional processes. An ensemble of discharges is likely to produce enough free charges to suggest a partial and stochastic coupling of the atmosphere to a large-scale magnetic field.

  6. Radio Detection of Extrasolar Planets

    E-print Network

    Ellingson, Steven W.

    Radio Detection of Extrasolar Planets: Present and Future Prospects T. Joseph W. Lazio1 & W. M.23 (Fisher et al. 2003) In last decade, exciting discovery of extrasolar planets n ~ 100 planetary systems n of extrasolar planets n ~ 100 planetary systems n Indirect detection via optical signature from host star

  7. Spectral signatures of photosynthesis. II. Coevolution with other stars and the atmosphere on extrasolar worlds.

    PubMed

    Kiang, Nancy Y; Segura, Antígona; Tinetti, Giovanna; Govindjee; Blankenship, Robert E; Cohen, Martin; Siefert, Janet; Crisp, David; Meadows, Victoria S

    2007-02-01

    As photosynthesis on Earth produces the primary signatures of life that can be detected astronomically at the global scale, a strong focus of the search for extrasolar life will be photosynthesis, particularly photosynthesis that has evolved with a different parent star. We take previously simulated planetary atmospheric compositions for Earth-like planets around observed F2V and K2V, modeled M1V and M5V stars, and around the active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as well as very low O2 content in case anoxygenic photosynthesis dominates. With a line-by-line radiative transfer model, we calculate the incident spectral photon flux densities at the surface of the planet and under water. We identify bands of available photosynthetically relevant radiation and find that photosynthetic pigments on planets around F2V stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in the near-infrared, in bands at 0.93-1.1 microm, 1.1-1.4 microm, 1.5-1.8 microm, and 1.8-2.5 microm. However, underwater organisms will be restricted to wavelengths shorter than 1.4 microm and more likely below 1.1 microm. M star planets without oxygenic photosynthesis will have photon fluxes above 1.6 microm curtailed by methane. Longer-wavelength, multi-photo-system series would reduce the quantum yield but could allow for oxygenic photosystems at longer wavelengths. A wavelength of 1.1 microm is a possible upper cutoff for electronic transitions versus only vibrational energy; however, this cutoff is not strict, since such energetics depend on molecular configuration. M star planets could be a half to a tenth as productive as Earth in the visible, but exceed Earth if useful photons extend to 1.1 microm for anoxygenic photosynthesis. Under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth. PMID:17407410

  8. Aerodynamic Heating and Deceleration During Entry into Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Aerodynamic Heating and Deceleration During Entry into Planetary Atmospheres. Dr. Chapman's lecture examines the physics behind spacecraft entry into planetary atmospheres. He explains how scientists determine if a planet has an atmosphere and how scientists can compute deceleration when the atmospheric conditions are unknown. Symbols and equations used for calculations for aerodynamic heating and deceleration are provided. He also explains heat transfer in bodies approaching an atmosphere, deceleration, and the use of ablation in protecting spacecraft from high temperatures during atmospheric entry. [Entire movie available on DVD from CASI as Doc ID 20070030962. Contact help@sti.nasa.gov

  9. Meteoric Material: An Important Component of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Moses, Julianne I.; Pesnell, W. Dean; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Interplanetary dust particles (IDPs) interact with all planetary atmospheres and leave their imprint as perturbations of the background atmospheric chemistry and structure. They lead to layers of metal ions that can become the dominant positively charged species in lower ionospheric regions. Theoretical models and radio occultation measurements provide compelling evidence that such layers exist in all planetary atmospheres. In addition IDP ablation products can affect neutral atmospheric chemistry, particularly at the outer planets where the IDPs supply oxygen compounds like water and carbon dioxide to the upper atmospheres. Aerosol or smoke particles from incomplete ablation or recondensation of ablated IDP vapors may also have a significant impact on atmospheric properties.

  10. Composition and origin of the atmosphere of Jupiter—an update, and implications for the extrasolar giant planets

    Microsoft Academic Search

    S. k. Atreya; P. R Mahaffy; H. b. Niemann; M. h. Wong; T. c. Owen

    2003-01-01

    New developments have led to this update of the composition and origin of Jupiter's atmosphere that were originally discussed in our Planet. Space Sci. 47 (1999) 1243 paper. Since Jupiter can provide important insight into the atmospheres of extrasolar giant planets (EGP), we also discuss here the possible implications of the first detection of an atmosphere on an EGP. The

  11. Atmospheric Circulation of Close-In Extrasolar Giant Planets: I. Global, Barotropic, Adiabatic Simulations

    E-print Network

    James Y-K. Cho; Kristen Menou; Brad Hansen; Sara Seager

    2007-10-21

    We present results from a set of over 300 pseudospectral simulations of atmospheric circulation on extrasolar giant planets with circular orbits. The simulations are of high enough resolution (up to 341 total and sectoral modes) to resolve small-scale eddies and waves, required for reasonable physical accuracy. In this work, we focus on the global circulation pattern that emerges in a shallow, ``equivalent-barotropic'', turbulent atmosphere on both tidally synchronized and unsynchronized planets. A full exploration of the large physical and numerical parameter-space is performed to identify robust features of the circulation. For some validation, the model is first applied to Solar System giant planets. For extrasolar giant planets with physical parameters similar to HD209458b--a presumably synchronized extrasolar giant planet, representative in many dynamical respects--the circulation is characterized by the following features: 1) a coherent polar vortex that revolves around the pole in each hemisphere; 2) a low number--typically two or three--of slowly-varying, broad zonal (east-west) jets that form when the maximum jet speed is comparable to, or somewhat stronger than, those observed on the planets in the Solar System; and, 3) motion-associated temperature field, whose detectability and variability depend on the strength of the net heating rate and the global root mean square wind speed in the atmosphere. In many ways, the global circulation is Earth-like, rather than Jupiter-like. However, if extrasolar giant planets rotate faster and are not close-in (therefore not synchronized), their circulations become more Jupiter-like, for Jupiter-like rotation rates.

  12. The Blue Dot Workshop: Spectroscopic Search for Life on Extrasolar Planets

    NASA Technical Reports Server (NTRS)

    Des Marais, David J. (Editor)

    1997-01-01

    This workshop explored the key questions and challenges associated with detecting life on an extrasolar planet. The final product will be a NASA Conference Publication which includes the abstracts from 21 talks, summaries of key findings, and recommendations for future research. The workshop included sessions on three related topics: the biogeochemistry of biogenic gases in the atmosphere, the chemistry and spectroscopy of planetary atmospheres, and the remote sensing of planetary atmospheres and surfaces. With the observation that planetary formation is probably a common phenomenon, together with the advent of the technical capability to locate and describe extrasolar planets, this research area indeed has an exciting future.

  13. Application of MODTRAN ™ to ExtraTerrestrial Planetary Atmospheres

    Microsoft Academic Search

    Lawrence S. Bernstein; Alexander Berk; Robert L. Sundberg

    MODTRAN ™ (1) is a widely used radiative-transfer (RT) code for computing the transmission and emission of the Earth's atmosphere. However, the RT algorithms used in MODTRAN ™ are generally applicable to any layered atmosphere, and, in principle, can be applied to any planetary atmosphere. The primary modification required for this application is the development of the appropriate spectral properties

  14. Aerodynamic Heating and Deceleration During Entry into Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Chapman, Dean R.

    1962-01-01

    Dr. Chapman's lecture examines the physics behind spacecraft entry into planetary atmospheres. He explains how scientists determine if a planet has an atmosphere and how scientists can compute deceleration when the atmospheric conditions are unknown. Symbols and equations used for calculations for aerodynamic heating and deceleration are provided. He also explains heat transfer in bodies approaching an atmosphere, deceleration, and the use of ablation in protecting spacecraft from high temperatures during atmospheric entry.

  15. Dynamics and Origin of Extra-solar Planetary Systems and Microlensing Detection of Extra-solar Planets

    NASA Technical Reports Server (NTRS)

    Peale, S. J.

    2003-01-01

    We compare a space-based microlensing search for planets, with a ground based microlensing search originally proposed by D. Tytler (Beichman, et al. 1996). Perturbations of microlensing light curves when the lens star has a planetary companion are sought by one wide angle survey telescope and an array of three or four followup narrow angle telescopes distributed in longitude that follow events with high precision, high time resolution photometry. Alternative ground based programs are considered briefly. With the four 2 meter telescopes distributed in longitude in the southern hemisphere in the Tytler proposal, observational constraints on a ground-based search for planets during microlensing events toward the center of the galaxy are severe. Probably less than 100 events could be monitored per year with high precision, high time resolution photometry with only about 42% coverage on the average regardless of how many events were discovered by the survey telescope. Statistics for the occurrence and properties for Jupiter-mass planets would be meaningful but relatively meager four years after the program was started, and meaningful statistics for Earth-mass planets would be non existent. In contrast, the 14,500 events in a proposed 4 year space based program (GEST = Galactic Exoplanet Survey Telescope) would yield very sound statistics on the occurrence, masses and separations of Jupiter-mass planets, and significant constraints on similar properties for Earth-mass planets. The significance of the Jupiter statistics would be to establish the frequency of planetary systems like our own, where terrestrial planets could exist inside the orbits of the giants.

  16. First International Conference on Laboratory Research for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Fox, Kenneth (editor); Allen, John E., Jr. (editor); Stief, Louis J. (editor); Quillen, Diana T. (editor)

    1990-01-01

    Proceedings of the First International Conference on Laboratory Research for Planetary Atmospheres are presented. The covered areas of research include: photon spectroscopy, chemical kinetics, thermodynamics, and charged particle interactions. This report contains the 12 invited papers, 27 contributed poster papers, and 5 plenary review papers presented at the conference. A list of attendees and a reprint of the Report of the Subgroup on Strategies for Planetary Atmospheres Exploration (SPASE) are provided in two appendices.

  17. Vibrational-Rotational Spectroscopy For Planetary Atmospheres, volume 1

    NASA Technical Reports Server (NTRS)

    Mumma, M. J. (editor); Fox, K. (editor); Hornstein, J. (editor)

    1982-01-01

    Comprehensive information on the composition and dynamics of the varied planetary atmospheres is summarized. New observations resulted in new demands for supporting laboratory studies. Spectra observed from spacecraft used to interpret planetary atmospheric structure measurements, to aid in greenhouse and cloud physics calculations, and to plan future experiments are discussed. Current findings and new ideas of physicists, chemists, and planetry astronomers relating to the knowledge of the structure of things large and small, of planets and of molecules are summarized.

  18. The search for extra-solar terrestrial planets: techniques and technology. Proceedings. Conference, Boulder, CO (USA), 14 - 17 May 1995

    Microsoft Academic Search

    J. M. Shull; H. A. Thronson Jr.; S. A. Stern

    1996-01-01

    The following topics were dealt with: search for extrasolar terrestrial planets, techniques, technology, planetary atmosphere evolution, solar system evolution, photometric search, radial velocity searches, photon-noise limit, astrometric searches, OSI mission, GAIA mission, ground-based interferometry, FRESIP mission, DARWIN project, and public involvement in extrasolar planet detection.

  19. Infrared experiments for spaceborne planetary atmospheres research. Full report

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The role of infrared sensing in atmospheric science is discussed and existing infrared measurement techniques are reviewed. Proposed techniques for measuring planetary atmospheres are criticized and recommended instrument developments for spaceborne investigations are summarized for the following phenomena: global and local radiative budget; radiative flux profiles; winds; temperature; pressure; transient and marginal atmospheres; planetary rotation and global atmospheric activity; abundances of stable constituents; vertical, lateral, and temporal distribution of abundances; composition of clouds and aerosols; radiative properties of clouds and aerosols; cloud microstructure; cloud macrostructure; and non-LTE phenomena.

  20. 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

  1. 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.

  2. Understanding other worlds: NASA's missions to find and characterize extrasolar planetary systems

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.

    2005-01-01

    About 150 extrasolar planets, mostly much more massive the Earth, are now known from ground-based observations. Earth-mass planets are very hard, if not impossible, to detect from the ground. The study of planets like our own Earth, orbiting in a 'habitable zone' around their parent stars, will require a new generation of space-based instruments.

  3. Remote Sensing of Planetary Properties and Biosignatures on Extrasolar Terrestrial Planets

    Microsoft Academic Search

    David J. Des Marais; Martin O. Harwit; Kenneth W. Jucks; James F. Kasting; Douglas N. C. Lin; Jonathan I. Lunine; Jean Schneider; Sara Seager; Wesley A. Traub; Neville J. Woolf

    2002-01-01

    The major goals of NASA's Terrestrial Planet Finder (TPF) and the European Space Agency's Darwin missions are to detect terrestrial-sized extrasolar planets directly and to seek spectroscopic evidence of habitable conditions and life. Here we recommend wavelength ranges and spectral features for these missions. We assess known spectroscopic molecular band features of Earth, Venus, and Mars in the context of

  4. Aerosols and chemistry in the planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Zhang, Xi

    This dissertation is devoted to studying aerosols and their roles in regulating chemistry, radiation, and dynamics of planetary atmospheres. In chapter I, we provided a fundamental mathematical basis for the quasi-equilibrium growth assumption, a well-accepted approach to representing formation of secondary organic aerosols (SOAs) in microphysical simulations in the Earth's atmosphere. Our analytical work not only explains the quasi-equilibrium growth, which emerges as a limiting case in our theory, but also predicts the other types of condensational growth, confirmed by the recent laboratory and field experiments. In chapter II, we presented a new photochemical mechanism in which the evaporation of the aerosols composed of sulfuric acid or polysulfur on the nightside of Venus could provide a sulfur source above 90 km. Our model results imply the enhancements of sulfur oxides such as SO, SO2, and SO3. This is inconsistent with the previous model results but in agreement with the recent ground-based and spacecraft observations. In chapters III and IV, we developed a nonlinear optimization approach to retrieve the aerosol and cloud structure on Jupiter from the visible and ultraviolet images acquired by the Cassini spacecraft, combined with the ground-based near-infrared observations. We produced the first realistic spatial distribution of Jovian stratospheric aerosols in latitudes and altitudes. We also retrieved the stratospheric temperature and hydrocarbon species based on the mid-infrared spectra from the Cassini and Voyager spacecrafts. Based on the above information, the accurate and detailed maps of the instantaneous radiative forcing in Jovian stratosphere are obtained, revealing a significant heating effect from the polar dark aerosols in the high latitude region and therefore a strong modulation on the global meridional circulation in the stratosphere of Jupiter. In chapter V, we study the transport of passive tracers, such as aerosols, acetylene (C2H 2) and ethane (C2H6) in the Jovian stratosphere, using both analytical and numerical approaches. We established several benchmark analytical solutions for the coupled photochemical-advective-diffusive system to understand its basic behaviors under different assumptions. A numerical two-dimensional chemical transport model is applied to Jupiter, and the effects of eddy mixing process and meridional circulation on the distributions of stratospheric species are discussed.

  5. Identification of Absorption Features in an Extrasolar Planet Atmosphere

    E-print Network

    T. S. Barman

    2007-04-09

    Water absorption is identified in the atmosphere of HD209458b by comparing models for the planet's transmitted spectrum to recent, multi-wavelength, eclipse-depth measurements (from 0.3 to 1 microns) published by Knutson et al. (2007). A cloud-free model which includes solar abundances, rainout of condensates, and photoionization of sodium and potassium is in good agreement with the entire set of eclipse-depth measurements from the ultraviolet to near-infrared. Constraints are placed on condensate removal by gravitational settling, the bulk metallicity, and the redistribution of absorbed stellar flux. Comparisons are also made to the Charbonneau et al. (2002) sodium measurements.

  6. A systematic retrieval analysis of secondary eclipse spectra. III. Diagnosing chemical disequilibrium in planetary atmospheres

    SciTech Connect

    Line, Michael R.; Yung, Yuk L., E-mail: mrl@gps.caltech.edu [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-12-10

    Chemical disequilibrium has recently become a relevant topic in the study of the atmospheres of transiting extrasolar planets, brown dwarfs, and directly imaged exoplanets. We present a new way of assessing whether or not a Jovian-like atmosphere is in chemical disequilibrium from observations of detectable or inferred gases such as H{sub 2}O, CH{sub 4}, CO, and H{sub 2}. Our hypothesis, based on previous kinetic modeling studies, is that cooler atmospheres will show stronger signs of disequilibrium than hotter atmospheres. We verify this with chemistry-transport models and show that planets with temperatures less than ?1200 K are likely to show the strongest signs of disequilibrium due to the vertical quenching of CO, and that our new approach is able to capture this process. We also find that in certain instances a planetary composition may appear in equilibrium when it actually is not due to the degeneracy in the shape of the vertical mixing ratio profiles. We determine the state of disequilibrium in eight exoplanets using the results from secondary eclipse temperature and abundance retrievals. We find that all of the planets in our sample are consistent with thermochemical equilibrium to within 3?. Future observations are needed to further constrain the abundances in order to definitively identify disequilibrium in exoplanet atmospheres.

  7. MEP and planetary climates: insights from a two-box climate model containing atmospheric dynamics

    PubMed Central

    Jupp, Tim E.; Cox, Peter M.

    2010-01-01

    A two-box model for equator-to-pole planetary heat transport is extended to include simple atmospheric dynamics. The surface drag coefficient CD is treated as a free parameter and solutions are calculated analytically in terms of the dimensionless planetary parameters ? (atmospheric thickness), ? (rotation rate) and ? (advective capability). Solutions corresponding to maximum entropy production (MEP) are compared with solutions previously obtained from dynamically unconstrained two-box models. As long as the advective capability ? is sufficiently large, dynamically constrained MEP solutions are identical to dynamically unconstrained MEP solutions. Consequently, the addition of a dynamical constraint does not alter the previously obtained MEP results for Earth, Mars and Titan, and an analogous result is presented here for Venus. The rate of entropy production in an MEP state is shown to be independent of rotation rate if the advective capability ? is sufficiently large (as for the four examples in the solar system), or if the rotation rate ? is sufficiently small. The model indicates, however, that the dynamical constraint does influence the MEP state when ? is small, which might be the case for some extrasolar planets. Finally, results from the model developed here are compared with previous numerical simulations in which the effect of varying surface drag coefficient on entropy production was calculated. PMID:20368254

  8. MEP and planetary climates: insights from a two-box climate model containing atmospheric dynamics.

    PubMed

    Jupp, Tim E; Cox, Peter M

    2010-05-12

    A two-box model for equator-to-pole planetary heat transport is extended to include simple atmospheric dynamics. The surface drag coefficient CD is treated as a free parameter and solutions are calculated analytically in terms of the dimensionless planetary parameters eta (atmospheric thickness), omega (rotation rate) and xi (advective capability). Solutions corresponding to maximum entropy production (MEP) are compared with solutions previously obtained from dynamically unconstrained two-box models. As long as the advective capability xi is sufficiently large, dynamically constrained MEP solutions are identical to dynamically unconstrained MEP solutions. Consequently, the addition of a dynamical constraint does not alter the previously obtained MEP results for Earth, Mars and Titan, and an analogous result is presented here for Venus. The rate of entropy production in an MEP state is shown to be independent of rotation rate if the advective capability xi is sufficiently large (as for the four examples in the solar system), or if the rotation rate omega is sufficiently small. The model indicates, however, that the dynamical constraint does influence the MEP state when xi is small, which might be the case for some extrasolar planets. Finally, results from the model developed here are compared with previous numerical simulations in which the effect of varying surface drag coefficient on entropy production was calculated. PMID:20368254

  9. Constraints on planetary formation from the discovery & study of transiting Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Triaud, A. H. M. J.

    2011-08-01

    After centuries of wondering about the presence of other worlds outside our Solar System, the first extrasolar planets were discovered about fifteen years ago. Since the quest continued. The greatest discovery of our new line of research, exoplanetology, has probably been the large diversity that those new worlds have brought forward; a diversity in mass, in size, in orbital periods, as well as in the architecture of the systems we discover. Planets very different from those composing our system have been detected. As such, we found hot Jupiters, gas giants which orbital period is only of a few days, mini-Neptunes, bodies five to ten time the mass of the Earth but covered by a thick gas layer, super-Earths of similar masses but rocky, lava worlds, and more recently, maybe the first ocean planet. Many more surprises probably await us. This thesis has for subject this very particular planet class: the hot Jupiters. Those astonishing worlds are still badly understood. Yet, thanks to the evolution of observational techniques and of the treatment of their signals, we probably have gathered as much knowledge from these worlds, than what was known of our own gas giants prior to their visit by probes. They are laboratories for a series of intense physical phenomena caused by their proximity to their star. Notably, these planets are found in average much larger than expected. In addition to these curiosities, their presence so close to their star is abnormal, the necessary conditions for the formation of such massive bodies, this close, not being plausible. Thus it is more reasonable to explain their current orbits by a formation far from their star, followed by an orbital migration. It is on this last subject that this thesis is on: the origin of hot Jupiters. The laws of physics are universal. Therefore, using the same physical phenomena, we need to explain the existence of hot Jupiters, while explaining why the Jupiter within our Solar System is found five times the Earth-Sun distance. In Astronomy, we cannot do experiments; we are a part of it. Instead, we search and characterise several similar objects in order to extract information out of them statistically. To answer our question, we needed to find several objects and detect the clues from their past history bringing us back to the processes that led to their formation. There are several manners with which one can find planets. For this thesis, the so-called transit method was used. It consists in detecting a periodic loss of light from a star in front of which a planet passes: a transit. This method is particularly sensitive to the presence of hot Jupiters. During this thesis, about fifty planets of such type have been discovered, about a third of the known hot Jupiters. Those planets are confirmed thanks to radial velocity measurements, the same technique that led to the discovery of the first extrasolar planet, around the star 51 Pegasi. The analysis of the stellar light affected by the presence of a planet around it, notably the light received during transit, allows us to know about the mass, the size of the planet, its orbital period, the shape of its orbit, its temperature, even the chemical composition of its atmosphere. Furthermore, these observations give us the occasion to study the star around which is found the planet, such as its mass, its size, its rotation speed, as well as give estimates on its age. One type of observations was employed in particular: the Rossiter-McLaughlin effect. During transit, this effect creates an anomaly compared to the expected radial velocities. Through a modelisation of this anomaly, it is possible to measure the projection of the angle between the orbital plane of the planet and the equatorial plane of the star, on the sky. In our System, all planets are located more or less in a same plane : the ecliptic. The equatorial plane of the Sun is also almost aligned with the ecliptic. This observation led Kant and Laplace to postulate on the formation of planets from matter spread in the form of a primordial disc around the Sun; such

  10. Time-dependent simulations of disk-embedded planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Stökl, A.; Dorfi, E. A.

    2014-03-01

    At the early stages of evolution of planetary systems, young Earth-like planets still embedded in the protoplanetary disk accumulate disk gas gravitationally into planetary atmospheres. The established way to study such atmospheres are hydrostatic models, even though in many cases the assumption of stationarity is unlikely to be fulfilled. Furthermore, such models rely on the specification of a planetary luminosity, attributed to a continuous, highly uncertain accretion of planetesimals onto the surface of the solid core. We present for the first time time-dependent, dynamic simulations of the accretion of nebula gas into an atmosphere around a proto-planet and the evolution of such embedded atmospheres while integrating the thermal energy budget of the solid core. The spherical symmetric models computed with the TAPIR-Code (short for The adaptive, implicit RHD-Code) range from the surface of the rocky core up to the Hill radius where the surrounding protoplanetary disk provides the boundary conditions. The TAPIR-Code includes the hydrodynamics equations, gray radiative transport and convective energy transport. The results indicate that diskembedded planetary atmospheres evolve along comparatively simple outlines and in particular settle, dependent on the mass of the solid core, at characteristic surface temperatures and planetary luminosities, quite independent on numerical parameters and initial conditions. For sufficiently massive cores, this evolution ultimately also leads to runaway accretion and the formation of a gas planet.

  11. Extrasolar Cosmochemistry

    NASA Astrophysics Data System (ADS)

    Jura, M.; Young, E. D.

    2014-05-01

    Evidence is now compelling that elements heavier than helium in many white dwarf atmospheres have accumulated by accretion from orbiting rocky bodies, often larger than 100 km in diameter, such as asteroids. Consequently, we now possess a powerful tool to measure the elemental constituents of extrasolar minor planets. To zeroth order, the accreted extrasolar parent bodies resemble bulk Earth: They are at least 85% by mass composed of oxygen, magnesium, silicon, and iron; carbon and ice are only trace constituents. Assembled data for white dwarf pollutions suggest that differentiation of extrasolar planetesimals, leading to iron-rich cores and aluminum-rich crusts, is common. Except for instances of unexpectedly high calcium abundances, the compositions of extrasolar planetesimals can be understood as resulting from processes similar to those controlling the formation and evolution of objects in the inner Solar System.

  12. Space and atmospheric planetary communication links as scientific tools

    Microsoft Academic Search

    H. U. Eichelberger; G. Prattes; K. Schwingenschuh; O. Aydogar; B. P. Besser; I. Jernej; H. Lammer; E. Leitgeb; H. I. M. Lichtenegger; M. Stachel; T. Tokano

    2008-01-01

    We investigate the combined use of acoustic, radio frequency and optical links for communication and scientific purposes for possible upcoming planetary missions, e.g., the proposed TandEM mission to the Saturnian moons Enceladus and Titan in the frame of ESApsilas Cosmic Vision 2015-2025 call. Based on experience with balloon flights and in-situ measurements in the venusian and terrestrial atmospheres and planetary

  13. Extrasolar Planet Research at Universidad de Chile

    NASA Astrophysics Data System (ADS)

    Rojo, Patricio; Hoyer, S.; Jenkins, J.; Jones, M.

    2010-10-01

    I will present the latest publications and current status on projects lead by researchers and doctoral candidates at Universidad de Chile in the area of extrasolar planets. Making use of the privileged access to world-class telescopes, the research efforts are focused in ground-based observations. Long- and short-term projects are currently underway: (1) exoplanetary atmospheric characterization, (2) monitoring of southern transiting planets searching for transit-timing variations, (3) the Calan-Hertfordshire Extrasolar planet RV search (CHEPS), and (4) study of post main-sequence planetary hosts.

  14. Planetary Research Center. [astronomical photography of planetary surfaces and atmospheres

    NASA Technical Reports Server (NTRS)

    Baum, W. A.; Millis, R. L.; Bowell, E. L. G.

    1974-01-01

    Extensive Earth-based photography of Mars, Jupiter, and Venus is presented which monitors the atmospheric and/or surface changes that take place day to day. Color pictures are included of the 1973 dust storm on Mars, showing the daily cycle of the storm's regeneration. Martian topography, and the progress of the storm is examined. Areas most affected by the storm are summarized.

  15. Planetary Atmospheres and the Search for Life.

    ERIC Educational Resources Information Center

    Owen, Tobias

    1982-01-01

    Different ways in which the atmospheres of different planets have originated and evolved are discussed. Includes tables on the atmospheric composition of: (1) Earth; (2) Mars; (3) Venus; (4)Titan (Saturn's Satellite); and (5) the outer planets. (SK)

  16. Planetary Radio Interferometry and Doppler Experiment (PRIDE) for Planetary Atmospheric Studies

    NASA Astrophysics Data System (ADS)

    Bocanegra Bahamon, Tatiana; Cimo, Giuseppe; Duev, Dmitry; Gurvits, Leonid; Molera Calves, Guifre; Pogrebenko, Sergei

    2015-04-01

    The Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique that allows the determination of the radial velocity and lateral coordinates of planetary spacecraft with very high accuracy (Duev, 2012). The setup of the experiment consists of several ground stations from the European VLBI Network (EVN) located around the globe, which simultaneously perform Doppler tracking of a spacecraft carrier radio signal, and are subsequently processed in a VLBI-style in phase referencing mode. Because of the accurate examination of the changes in phase and amplitude of the radio signal propagating from the spacecraft to the multiple stations on Earth, the PRIDE technique can be used for several fields of planetary research, among which planetary atmospheric studies, gravimetry and ultra-precise celestial mechanics of planetary systems. In the study at hand the application of this technique for planetary atmospheric investigations is demonstrated. As a test case, radio occultation experiments were conducted with PRIDE having as target ESA's Venus Express, during different observing sessions with multiple ground stations in April 2012 and March 2014. Once each of the stations conducts the observation, the raw data is delivered to the correlation center at the Joint Institute for VLBI in Europe (JIVE) located in the Netherlands. The signals are processed with a high spectral resolution and phase detection software package from which Doppler observables of each station are derived. Subsequently the Doppler corrected signals are correlated to derive the VLBI observables. These two sets of observables are used for precise orbit determination. The reconstructed orbit along with the Doppler observables are used as input for the radio occultation processing software, which consists of mainly two modules, the geometrical optics module and the ray tracing inversion module, from which vertical density profiles, and subsequently, temperature and pressure profiles of Venus' atmosphere were derived. The demonstration of the capability of PRIDE as a radio science instrument for planetary atmospheric studies is developed in the framework of the upcoming ESA's JUICE mission to study Jupiter's system.

  17. NASA Planetary Astronomy Lunar Atmospheric Imaging Study

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1996-01-01

    Authors have conducted a program of research focused on studies of the lunar atmosphere. Also present preliminary results of an ongoing effort to determine the degree that metal abundances in the lunar atmosphere are stoichiometric, that is, reflective of the lunar surface composition. We make the first-ever mid-ultraviolet spectroscopic search for emission from the lunar atmosphere.

  18. Understanding the Outer Planets and Planetary Atmospheres

    E-print Network

    Mojzsis, Stephen J.

    with the volcanic atmospheres of Io and Enceladus · Escape of atmospheres from Mars, Mercury, Europa, and Pluto Rings One of the most enduring symbols of space exploration is a planet surrounded by a system of rings for Atmospheric and Space Physics (LASP) combines all aspects of space exploration through our expertise

  19. Crossing the Boundaries in Planetary Atmospheres - From Earth to Exoplanets

    NASA Technical Reports Server (NTRS)

    Simon-Miller, Amy A.; Genio, Anthony Del

    2013-01-01

    The past decade has been an especially exciting time to study atmospheres, with a renaissance in fundamental studies of Earths general circulation and hydrological cycle, stimulated by questions about past climates and the urgency of projecting the future impacts of humankinds activities. Long-term spacecraft and Earth-based observation of solar system planets have now reinvigorated the study of comparative planetary climatology. The explosion in discoveries of planets outside our solar system has made atmospheric science integral to understanding the diversity of our solar system and the potential habitability of planets outside it. Thus, the AGU Chapman Conference Crossing the Boundaries in Planetary Atmospheres From Earth to Exoplanets, held in Annapolis, MD from June 24-27, 2013 gathered Earth, solar system, and exoplanet scientists to share experiences, insights, and challenges from their individual disciplines, and discuss areas in which thinking broadly might enhance our fundamental understanding of how atmospheres work.

  20. Saturn's rotation period from its atmospheric planetary-wave configuration

    E-print Network

    Read, Peter L.

    LETTERS Saturn's rotation period from its atmospheric planetary-wave configuration P. L. Read1 , T III reference frame) is commonly used to infer its bulk rotation1 . Saturn's dipole magnetic field s measured 28 years ago by Voyager2 . Here we report a determination of Saturn's rotation period based

  1. An application of gas chromatography to planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Oyama, V.

    1974-01-01

    A gas chromatography developed for the Viking experiment is described. The instrument is designed to measure gases in planetary atmospheres and head space in a chamber. It is hoped that the chromatograph will also measure any biological activity present in these environments.

  2. Dynamical Simulations of Extrasolar Planetary Systems with Debris Disks Using a GPU Accelerated N-Body Code

    NASA Astrophysics Data System (ADS)

    Moore, Alexander

    This thesis begins with a description of a hybrid symplectic integrator named QYMSYM which is capable of planetary system simulations. This integrator has been programmed with the Compute Unified Device Architecture (CUDA) language which allows for implementation on Graphics Processing Units (GPUs). With the enhanced compute performance made available by this choice, QYMSYM was used to study the effects debris disks have on the dynamics of the extrasolar planetary systems HR 8799 and KOI-730. The four planet system HR 8799 was chosen because it was known to have relatively small regions of stability in orbital phase space. Using this fact, it can be shown that a simulated debris disk of moderate mass around HR 8799 can easily pull this system out of these regions of stability. In other cases it is possible to migrate the system to a region of stability - although this requires significantly more mass and a degree of fine tuning. These findings suggest that previous studies on the stability of HR 8799 which do not include a debris disk may not accurately report on the size and location of the stable orbital phase space available for the planets. This insight also calls into question the practice of using dynamical simulations to help constrain observed planetary orbital data. Next, by studying the stability of another four planet system, KOI-730, whose planets are in an 8:6:4:3 mean motion resonance, we were additionally able to determine mass constraints on debris disks for KOI-730 like Kepler objects. Noting that planet inclinations increase by a couple of degrees when migrating through a Neptune mass debris disk, and that planet candidates discovered by the Kepler Space Telescope are along the line of site, it is concluded that significant planetary migration did not occur among the Kepler objects. This result indicates that Kepler objects like KOI-730 have relatively small or stable debris disks which did not cause migration of their planets - ruling out late-heavy bombardment style events. In both cases, the inclusion of debris disks in our simulations provided new results or useful constraints.

  3. In situ observations of the atmospheres of terrestrial planetary bodies

    NASA Astrophysics Data System (ADS)

    Harri, Ari-Matti

    2005-11-01

    Direct observations of planetary atmospheres are scarce and significantly more data are needed for the understanding of their behavior. The principal theme of this dissertation is the exploration of planetary atmospheres by means of in situ observations, focusing on investigations performed by payloads operating on the planetary surface. The contextual frame includes the whole palette of planetary exploration including definition of scientific objectives, observational strategies, scientific payload and data analysis, as well as development of technological solutions and simulation models for planetary missions. Thus approach also led to the initiation of the planetary missions MetNet and NetLander to Mars. This work contributes to both in situ atmospheric observations and atmospheric modeling, which are strongly intertwined. Modeling efforts require observations to give solid background and foundation for the simulations, and on the other hand, definition of observational strategies and instrumentation gets guidance from modeling efforts to optimize the use of mission resources, as is successfully demonstrated in this dissertation. The dissertation consists of Summary and nine original scientific publications. Publications 1 to 7 and Summary address the development of new atmospheric science payloads for exploration missions to Mars and Titan, a Saturnian moon. Actual and planned missions included are the Mars-96 Program and its Small Surface Stations and Penetrators during the years 1988-1996, PPI/HASI onboard the Cassini/Huygens spacecraft to Saturn and its moon Titan in 1989-2005, the MET-P payload onboard the Mars Polar Lander in 1997-1999, the BAROBIT instrument for the Beagle 2 lander in 2001-2003, the NetLander Mars Mission in 1997-2001 and the ongoing Mars MetNet Mission, started in 2000. Specifically, Publication 4 reviews the sensor qualification process that facilitated the use of new type of atmospheric sensors at Mars, while Publications 2 and 7, as well as Summary, address the highly successful determination of the Titan atmospheric pressure profile. Publication 8 combines in situ observations and simulations by analyzing Mars Pathfinder measurements with the help of a Martian mesoscale atmospheric model. Finally, in Publication 9 the effect of airborne dust and CO 2 on the radiative transfer in the Martian atmosphere is assessed and a new radiative transfer paramerization scheme for the mesoscale model is introduced.

  4. The Presence of Methane in the Atmosphere of an Extrasolar Planet

    NASA Technical Reports Server (NTRS)

    Swain, Mark R.; Vasisht, Gautam; Tinetti, Giovanna

    2008-01-01

    Molecules present in the atmospheres of extrasolar planets are expected to influence strongly the balance of atmospheric radiation, to trace dynamical and chemical processes, and to indicate the presence of disequilibrium effects. As molecules have the potential to reveal atmospheric conditions and chemistry, searching for them is a high priority. The rotational-vibrational transition bands of water, carbon monoxide and methane are anticipated to be the primary sources of non-continuum opacity in hot-Jupiter planets. As these bands can overlap in wavelength, and the corresponding signatures from them are weak, decisive identification requires precision infrared spectroscopy. Here we report a near-infrared transmission spectrum of the planet HD 189733b that shows the presence of methane. Additionally, a resolved water vapour band at 1.9 (micro)m confirms the recent claim4 of water in this object. On thermochemical grounds, carbon monoxide is expected to be abundant in the upper atmosphere of hot-Jupiter planets, but is not identifiable here; therefore the detection of methane rather than carbon monoxide in such a hot planet could signal the presence of a horizontal chemical gradient away from the permanent dayside, or it may imply an ill-understood photochemical mechanism that leads to an enhancement of methane.

  5. The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres.

    PubMed

    Goldblatt, Colin; Watson, Andrew J

    2012-09-13

    The ultimate climate emergency is a 'runaway greenhouse': a hot and water-vapour-rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only after the surface reaches approximately 1400 K and emits radiation in the near-infrared, where water is not a good greenhouse gas. This would evaporate the entire ocean and exterminate all planetary life. Venus experienced a runaway greenhouse in the past, and we expect that the Earth will in around 2 billion years as solar luminosity increases. But could we bring on such a catastrophe prematurely, by our current climate-altering activities? Here, we review what is known about the runaway greenhouse to answer this question, describing the various limits on outgoing radiation and how climate will evolve between these. The good news is that almost all lines of evidence lead us to believe that is unlikely to be possible, even in principle, to trigger full a runaway greenhouse by addition of non-condensible greenhouse gases such as carbon dioxide to the atmosphere. However, our understanding of the dynamics, thermodynamics, radiative transfer and cloud physics of hot and steamy atmospheres is weak. We cannot therefore completely rule out the possibility that human actions might cause a transition, if not to full runaway, then at least to a much warmer climate state than the present one. High climate sensitivity might provide a warning. If we, or more likely our remote descendants, are threatened with a runaway greenhouse, then geoengineering to reflect sunlight might be life's only hope. Injecting reflective aerosols into the stratosphere would be too short-lived, and even sunshades in space might require excessive maintenance. In the distant future, modifying Earth's orbit might provide a sustainable solution. The runaway greenhouse also remains relevant in planetary sciences and astrobiology: as extrasolar planets smaller and nearer to their stars are detected, some will be in a runaway greenhouse state. PMID:22869797

  6. On the stability of extrasolar planetary systems and other closely orbiting pairs

    NASA Astrophysics Data System (ADS)

    Adams, Fred C.; Bloch, Anthony M.

    2015-02-01

    This paper considers the stability of tidal equilibria for planetary systems in which stellar rotation provides a significant contribution to the angular momentum budget. We begin by applying classic stability considerations for two bodies to planetary systems - where one mass is much smaller than the other. The application of these stability criteria to a subset of the Kepler sample indicates that the majority of the systems are not in a stable equilibrium state. Motivated by this finding, we generalize the stability calculation to include the quadrupole moment for the host star. In general, a stable equilibrium requires that the total system angular momentum exceeds a minimum value (denoted here as LX) and that the orbital angular momentum of the planet exceeds a minimum fraction of the total. Most, but not all, of the observed planetary systems in the sample have enough total angular momentum to allow an equilibrium state. Even with the generalizations of this paper, however, most systems have too little orbital angular momentum (relative to the total) and are not in an equilibrium configuration. Finally, we consider the time evolution of these planetary systems; the results constrain the tidal quality factor of the stars and suggest that 106 ? Q* ? 107.

  7. Planetary migration and extrasolar planets in the 2\\/1 mean-motion resonance

    Microsoft Academic Search

    C. Beaugé; T. A. Michtchenko; S. Ferraz-Mello

    2006-01-01

    In this paper, we present a new set of corotational solutions for the 2\\/1 commensurability, including previously known solutions and new results. Comparisons with observed exoplanets show that current orbital fits of three proposed resonant planetary systems are consistent with apsidal corotations. We also discuss the possible relationship between the current orbital elements fits of known exoplanets in the 2\\/1

  8. Understanding the formation and composition of hazes in planetary atmospheres that contain carbon monoxide

    NASA Astrophysics Data System (ADS)

    Hörst, S. M.; Yoon, Y. H.; Hicks, R. K.; Tolbert, M. A.

    2012-09-01

    Measurements from the Cassini Plasma Spectrometer (CAPS) have revealed the presence of molecules in Titan's ionosphere with masses in excess of hundreds of amu. Negative ions with mass/charge (m/z) up to 10,000 amu/q [1] and positive ions with m/z up to 400 amu/q [2] have been detected. CAPS has also observed O+ flowing into Titan's upper atmosphere [3], which appears to originate from Enceladus and is likely the source of oxygen bearing molecules in Titan's atmosphere [4]. The observed O+ is deposited in the region now known to contain large organic molecules. A recent Titan atmosphere simulation experiment has shown that incorporation of oxygen into Titan aerosol analogues results in the formation of all five nucleotide bases and the two smallest amino acids, glycine and alanine [5]. Similar chemical processes may have occurred in the atmosphere of the early Earth, or in the atmospheres of extrasolar planets; atmospheric aerosols may be an important source of the building blocks of life. Atmospheric aerosols play an important role in determining the radiation budget of an atmosphere and can also provide a wealth of organic material to the surface. The presence of atmospheric aerosols has been invoked to explain the relatively featureless spectrum of HD 189773b, including the lack of predicted atmospheric Na and K spectral lines [9]. The majority of the O+ precipitating into Titan's atmosphere forms CO (O(3P)+CH3 -> CO+H2+H) [4]. CO has also been detected in the atmospheres of a number of exoplanets including HD 189733b, HD 209458b, and WASP-12b [6-8]. It is therefore important to understand the role CO plays in the formation and composition of hazes in planetary atmospheres. Using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) (see e.g. [10]) we have obtained in situ composition measurements of aerosol particles (so-called "tholins") produced in N2/CH4/CO gas mixtures subjected to either FUV radiation (deuterium lamp, 115-400 nm) or a spark discharge for a range of initial CO mixing ratios. A comparison of the composition of tholins produced using the two different energy sources will be presented. The effect of variation of CO mixing ratio on aerosol production and composition will also be discussed.

  9. What maintains the zonal circulation in planetary atmospheres

    SciTech Connect

    Mayr, H.G.; Chan, K.L.; Harris, I.; Schatten, K. (NASA, Goddard Space Flight Center, Greenbelt, MD (USA))

    1991-01-01

    The latest Voyager observations have shown large zonal velocities in Neptune's atmosphere, with some indication of alternating jets. Similar wind velocities have also been observed on Venus and are characteristic of planetary atmospheres in general, which is remarkable considering that the available solar or internal heating varies by more than a factor of 1000. A simplified model of the planetary circulation which provides some qualitative understanding is discussed. The basic assumption is that the source driving the circulation is also generating the dissipating eddies which are simulated by diffusion. Thus, the magnitude and structure of the zonal circulation are independent both of the source and the dissipation rate. The zonal velocities are related to the speed of sound and are of comparable magnitude in different atmospheres; although the available heating varies by a large factor, and the planetary parameters vary over a wide range. The alternating jets are described by a convective eigenmode which develops when energy transport out of the planetary interior is important, as is the case on Jupiter, Neptune, and Saturn. 26 refs.

  10. Consequences of planetary migration: Kuiper belt dynamics and atmospheric escape from hot Jupiters

    NASA Astrophysics Data System (ADS)

    Murray-Clay, Ruth Ann

    The current resonance structure of the Kuiper belt suggests that during the late stages of planet formation, Neptune migrated outward as it scattered residual planetesimal debris. Extrasolar planetary systems also show evidence for planetary migration. Approximately 1/5 of the extrasolar planets discovered to date are "hot Jupiters," which likely exchanged angular momentum with gas disks, migrating large distances inward to reach their current semi-major axes of ~0.05 AU. In this thesis, I discuss three consequences of planetary migration. (1) During its migration, Neptune captured Kuiper belt objects (KBOs) into mean motion resonances. The current spatial distribution of KBOs in a particular resonance, the 2:1, acts as a celestial speedometer--fast planetary migration generates a larger population of 2:1 resonant KBOs trailing rather than leading Neptune on the sky. We provide an explanation of this phenomenon for the first time. Central to our understanding is how planetary migration shifts the equilibrium points of the superposed direct and indirect potentials felt by a KBO. The currently observed distribution of 2:1 KBOs excludes total migration times < 20 Myr with >99.65% confidence and is statistically consistent with the even population generated by slow migration. However, these observations are beset by systematic uncertainties. Observations with new telescopes such as PanSTARRS or LSST will tell us how quickly Neptune could have migrated. (2) Neptune's migration, powered by scattering planetesimal debris, was stochastic ("noisy"). Extreme stochasticity defeats resonance capture. We construct a theory analogous to Brownian motion for how a planet's orbital semi-major axis fluctuates in response to random planetesimal scatterings. The degree of stochasticity in Neptune's migration depends both on the sizes of the planetesimals driving migration and on their orbital elements and cannot currently be computed using N-body simulations. We find that capture of resonant Kuiper belt objects by a migrating Neptune remains effective if the bulk of the primordial disk was locked in bodies having sizes [Special characters omitted.] km and if the fraction of disk mass in objects with sizes [Special characters omitted.] 1000 km was less than a few percent. Coagulation simulations produce a size distribution of primordial planetesimals that easily satisfies these constraints. We conclude that stochasticity did not interfere with Neptune's ability to capture and retain KBOs in first-order resonances during its migration. (3) Photoionization heating from UV radiation incident on the atmospheres of hot Jupiters drives planetary mass loss. Observations of stellar Lyman- a absorption at high velocities (±100 km s -1 ) have suggested that the hot Jupiter HD 209458b is losing atomic hydrogen. We show that mass loss takes the form of a hydrodynamic ("Parker") wind, emitted either from the planet's dayside during lulls in the stellar wind, or from the nightside when heat is transported there by horizontal flows. A hot Jupiter loses at most ~0.06% of its mass during its host star's pre-main-sequence phase and ~0.6% of its mass during the star's main sequence lifetime. At no stage do planetary winds reach velocities of ±100 km s -1 . We conclude that while UV radiation does indeed drive winds from hot Jupiters, such winds cannot significantly alter planet ary masses during any evolutionary stage, nor can they generate the observed decrements in Lya flux in HD 209458b.

  11. Conservation of Total Escape from Hydrodynamic Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Tian, F.

    2013-12-01

    Atmosphere escape is one key process controlling the evolution of planets. However, estimating the escape rate in any detail is difficult because there are many physical processes contributing to the total escape rate. Here we show that as a result of energy conservation the total escape rate from hydrodynamic planetary atmospheres where the outflow remains subsonic is nearly constant under the same stellar XUV photon flux when increasing the escape efficiency from the exobase level, consistent with the energy limited escape approximation. Thus the estimate of atmospheric escape in a planet's evolution history can be greatly simplified.

  12. Tectonic implications of radiogenic noble gases in planetary atmospheres

    SciTech Connect

    Turcotte, D.L.; Schubert, G.

    1988-04-01

    An account is given of the ways in which the He-4 and Ar-40 radiogenic isotopes furnish important constraints on planetary interior tectonics. In the case of the earth, where there are such independent constraints on radiogenic isotope concentrations as observed surface heat flow, the specification of radiogenic isotope concentration allows the interpretation of data on the Ar-40 atmospheric mass and mantle He-4 in terms of models for the entire mantle and of layered mantle convection. He loss rate estimates through the Venus atmosphere indicate a flux that is nearly equal to that through the earth atmosphere. 34 references.

  13. Spectroscopic analyses of the parent stars of extrasolar planetary system candidates

    Microsoft Academic Search

    Guillermo Gonzalez

    1998-01-01

    The stars rho () 1 Cnc, rho CrB, 16 Cyg B, 51 Peg, 47 UMa, 70 Vir, and HD 114762 have recently been proposed to harbor planetary mass companions based on small amplitude radial velocity variations. From spectroscopic analyses we derive the following values of [Fe\\/H] for these stars: 0.29, -0.29, 0.06, 0.21, 0.01, -0.03, and -0.60 (all with an

  14. Direct detection of extra-solar planetary systems from the ground and space

    NASA Technical Reports Server (NTRS)

    Terrile, R. J.

    1986-01-01

    This paper discusses recent work in the development of instrumentation used for the direct detection of planetary systems from ground-based and space-based observatories. Direct methods such as CCD coronagraphic imaging of nearby stars must overcome the large contrast differences between parent star and the circumstellar material. However, these methods have the advantage over indirect methods in that more advanced space-based direct detection instrumentation can lead to a significantly greater science return.

  15. Infrared quantitative spectroscopy and planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Flaud, J.-M.

    2009-04-01

    Optical measurements of atmospheric minor constituents are carried out using spectrometers working in the UV-visible, infrared and microwave spectral ranges. In all cases the quality of the analysis and of the interpretation of the atmospheric spectra requires the best possible knowledge of the molecular parameters of the species of interest. To illustrate this point we will concentrate on recent laboratory studies of nitric acid, chlorine nitrate and formaldehyde. Nitric acid is one of the important minor constituent of the terrestrial atmosphere. Using new and accurate experimental results concerning the spectroscopic properties of the H14NO3 and H15NO3 molecules, as well as improved theoretical methods (Perrin et al., 2004), it has been possible to generate an improved set of line parameters for these molecules in the 11.2 ?m spectral region. These line parameters were used to detect for the first time the H15NO3 molecule in the atmosphere analyzing atmospheric spectra recorded by the MIPAS experiment. The retrievals of chlorine nitrate profiles are usually performed using absorption cross sections (Birk and Wagner, 2003). Following a high resolution analysis of the ?3 and ?4bands of this species in the 12.8 ?m region wepropose, as a possibility, to use line by line calculation simulating its ?4Q-branch for the atmospheric temperature and pressure ranges. For the measurement of atmospheric formaldehyde concentrations, mid-infrared and ultraviolet absorptions are both used by ground, air or satellite instruments. It is then of the utmost importance to have consistent spectral parameters in these various spectral domains. Consequently the aim of the study performed at LISA (Gratien et al., 2007) was to intercalibrate formaldehyde spectra in the infrared and ultraviolet regions acquiring simultaneously UV and IR spectra using a common optical cell. The results of the work will be presented. Also high resolution infrared data derived from Perrin et al., 2003 have been used to determine vertical distributions from the upper troposphere to the stratopause using the high spectral resolution measurements of MIPAS (Steck et al., 2008). References: M. Birk, G. Wagner, J. Quant. Spectros. Radiat.Transfer, 82, 443, 2003. G. Brizzi, M. Carlotti, J.-M. Flaud, A. Perrin and M. Ridolfi, Geophys. Res. Lett., 34, L03802, 2006. A. Gratien, B. Picquet-Varrault, J. Orphal, E. Perraudin, J.-F. Doussin and J.-M. Flaud, J. Geophys. Res., 112, D05305, 2007. A. Perrin, F. Keller and J.-M. Flaud, J. Mol. Spectrosc., 221, 192, 2003. A. Perrin, J. Orphal, J.-M. Flaud, S. Klee, G. Mellau, H. Mader, D. Walbrodt and M. Winnewisser, J. Mol. Spectrosc, 228, 375, 2004. T. Steck, N. Glatthor, T. von Clarmann, H. Fischer, J. M. Flaud, B. Funke, U. Grabowski, M. Hopfner, S. Kellmann, A. Linden, A. Perrin, and G. P. Stiller, Atm. Chem. Phys., 8, 463, 2008.

  16. A Novel Diagnosis of Chemical Disequilibrium in Extrasolar Planet and Substellar Object Atmospheres

    NASA Astrophysics Data System (ADS)

    Line, Michael R.; Yung, Y. L.

    2013-10-01

    With recent advancements in spectroscopic capabilities, characterization of the temperatures and compositions of extra-solar planets is becoming more prevalent. One outstanding issue one can address with temperature and abundance determinations is the role that disequilibrium plays in sculpting the atmospheric compositions. A variety of disequilibrium models now exist in the literature to explore various planets and the effects that photochemistry and vertical mixing have on the molecular abundances. In this investigation we introduce a novel approach to diagnosing disequilibrium without the need of sophisticated photochemical/kinetics models. In short, we define an “equilibrium” line as a function of a representative planet temperature. If we can determine the abundances of H2O, CH4, CO, and H2, we can evaluate a simple analytic formula to quickly assess whether or not the atmospheric composition is in disequilibrium. We verify the usefulness of this approach with state-of-the-art chemistry-transport models and find that, as expected, cooler planets tend to show the strongest signs of disequilibrium.

  17. The Edison infrared space observatory and the study of extra-solar planetary material

    NASA Technical Reports Server (NTRS)

    Thronson, H. A., Jr.; Hawarden, T. G.; Bally, J.; Rapp, D.; Stern, S. A.

    1994-01-01

    Edison is a proposed large-aperture, radiatively-cooled space observatory planned to operate at wavelengths between 2 and 130 micrometers or longer. Current estimates for the telescope allow an aperture of 1.7 m which will achieve a final equilibrium temperature of about 30 K, although use of cryocoolers may permit temperatures below 20 K. Edison will be a powerful tool to investigate our Solar System, as well as planetary material around distant stars. At near- and mid-infrared wavelengths, where planetary material emits most of its radiation, Edison will be the most sensitive photometric and spectroscopic observatory under current consideration by the space agencies. With its large aperture, Edison will be able both to resolve the structure in nearby circumstellar 'Vega disks' and to discriminate faint IR emission in the crowded environment of the galactic plane. With its long lifetime, Edison will allow extensive follow-up observations and increase the likelihood of catching transient events. We propose Edison as a precursor to elements of a future space-based IR interferometer.

  18. The Explicit Planetary Isentropic-Coordinate (EPIC) Atmospheric Model

    Microsoft Academic Search

    T. E. Dowling; A. S. Fischer; P. J. Gierasch; J. Harrington; R. P. LeBeau; C. M. Santori

    1998-01-01

    We describe a new general circulation model (GCM) designed for planetary atmospheric studies called the EPIC model. This is a finite-difference model based on the isentropic-coordinate scheme of Hsu and Arakawa (1990.Mon. Wea. Rev.118, 1933–1959). We report on previously undocumented modifications, additions, and key practical issues that experience running the model has revealed to be important. The model integrates the

  19. The Explicit Planetary Isentropic-Coordinate (EPIC) Atmospheric Model

    Microsoft Academic Search

    T. E. Dowling; A. S. Fischer; P. J. Gierasch; J. Harrington; R. P. Lebeau; C. M. Santori

    1998-01-01

    We describe a new general circulation model (GCM) designed for planetary atmospheric studies called the EPIC model. This is a finite-difference model based on the isentropic-coordinate scheme of Hsu and Arakawa (1990. Mon. Wea. Rev. 118, 1933-1959). We report on previously undocumented modifications, additions, and key practical issues that experience running the model has revealed to be important. The model

  20. Infrared laboratory studies of synthetic planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Williams, D.

    1974-01-01

    Research involving a test of multiplicative transmittance for mixed absorbing gases when their lines are broadened by H2 and He, which are constituents of the atmospheres of the major planets was conducted. The results indicate that the multiplicative law as originally formulated can be applied with confidence. The broadening of individual lines in the CO fundamental by various gases has been investigated. The results indicate that the ratio of the self-broadening ability of CO to the line-broadening ability of foreign gases is greater for lines in the band wings than for lines near the band center when the molecular mass of the broadener is less than that of CO. The results have been interpreted in terms of a phenomenological theory. Studies of the relative line broadening abilities of foreign gases have provided information that can be used to provide optical collision cross sections for individual lines in the CO fundamental.

  1. Dications and thermal ions in planetary atmospheric escape

    NASA Astrophysics Data System (ADS)

    Lilensten, J.; Simon Wedlund, C.; Barthélémy, M.; Thissen, R.; Ehrenreich, D.; Gronoff, G.; Witasse, O.

    2013-01-01

    In the recent years, the presence of dications in the atmospheres of Mars, Venus, Earth and Titan has been modeled and assessed. These studies also suggested that these ions could participate to the escape of the planetary atmospheres because a large fraction of them is unstable and highly energetic. When they dissociate, their internal energy is transformed into kinetic energy which may be larger than the escape energy. The goal of this study is to assess the impact of the doubly-charged ions in the escape of CO2-dominated planetary atmospheres and to compare it to the escape of thermal photo-ions. We solve a Boltzmann transport equation at daytime taking into account the dissociative states of CO2++ for a simplified single constituent atmosphere of a case-study planet. We compute the escape of fast ions using a Beer-Lambert approach. We study three test-cases. On a Mars-analog planet in today's conditions, we retrieve the measured electron escape flux. When comparing the two mechanisms (i.e. excluding solar wind effects, sputtering, etc.), the escape due to the fast ions issuing from the dissociation of dications may account for up to 6% of the total and the escape of thermal ions for the remaining. We show that these two mechanisms cannot explain the escape of the atmosphere since the magnetic field vanished and even contribute only marginally to this loss. We show that with these two mechanisms, the atmosphere of a Mars analog planet would empty in another giga years and a half. At Venus orbit, the contribution of the dications in the escape rate is negligible. When simulating the hot Jupiter HD 209458 b, the two processes cannot explain the measured escape flux of C+. This study shows that the dications may constitute a source of the escape of planetary atmospheres which had not been taken into account until now. This source, although marginal, is not negligible. The influence of the photoionization is of course large, but cannot explain alone the loss of Mars' atmosphere nor the atmospheric escape of HD 209458 b.

  2. Periastron Precession Measurements in Transiting Extrasolar Planetary Systems at the Level of General Relativity

    E-print Network

    Pál, András

    2008-01-01

    Transiting exoplanetary systems are surpassingly important among the planetary systems since they provide the widest spectrum of information for both the planet and the host star. If a transiting planet is on an eccentric orbit, the duration of transits T_D is sensitive to the orientation of the orbital ellipse relative to the line of sight. The precession of the orbit results in a systematic variation in both the duration of individual transit events and the observed period between successive transits, P_obs. The periastron of the ellipse slowly precesses due to general relativity and possibly the presence of other planets in the system. This secular precession can be detected through the long-term change in P_obs (transit timing variations, TTV) or in T_D (transit duration variations, TDV). We estimate the corresponding precession measurement precision for repeated future observations of the known eccentric transiting exoplanetary systems (XO-3b, HD 147506b, GJ 436b and HD 17156b) using existing or planned ...

  3. Periastron precession measurements in transiting extrasolar planetary systems at the level of general relativity

    NASA Astrophysics Data System (ADS)

    Pál, András; Kocsis, Bence

    2008-09-01

    Transiting exoplanetary systems are surpassingly important among the planetary systems since they provide the widest spectrum of information for both the planet and the host star. If a transiting planet is on an eccentric orbit, the duration of transits TD is sensitive to the orientation of the orbital ellipse relative to the line of sight. The precession of the orbit results in a systematic variation in both the duration of individual transit events and the observed period between successive transits, Pobs. The periastron of the ellipse slowly precesses due to general relativity and possibly the presence of other planets in the system. This secular precession can be detected through the long-term change in Pobs (transit timing variations, TTV) or in TD (transit duration variations, TDV). We estimate the corresponding precession measurement precision for repeated future observations of the known eccentric transiting exoplanetary systems (XO-3b, HD 147506b, GJ 436b and HD 17156b) using existing or planned space-borne instruments. The TDV measurement improves the precession detection sensitivity by orders of magnitude over the TTV measurement. We find that TDV measurements over a approximately 4yr period can typically detect the precession rate to a precision well exceeding the level predicted by general relativity.

  4. Periastron Precession Measurements in Transiting Extrasolar Planetary Systems at the Level of General Relativity

    E-print Network

    András Pál; Bence Kocsis

    2008-06-04

    Transiting exoplanetary systems are surpassingly important among the planetary systems since they provide the widest spectrum of information for both the planet and the host star. If a transiting planet is on an eccentric orbit, the duration of transits T_D is sensitive to the orientation of the orbital ellipse relative to the line of sight. The precession of the orbit results in a systematic variation in both the duration of individual transit events and the observed period between successive transits, P_obs. The periastron of the ellipse slowly precesses due to general relativity and possibly the presence of other planets in the system. This secular precession can be detected through the long-term change in P_obs (transit timing variations, TTV) or in T_D (transit duration variations, TDV). We estimate the corresponding precession measurement precision for repeated future observations of the known eccentric transiting exoplanetary systems (XO-3b, HD 147506b, GJ 436b and HD 17156b) using existing or planned space-borne instruments. The TDV measurement improves the precession detection sensitivity by orders of magnitude over the TTV measurement. We find that TDV measurements over a ~4 year period can typically detect the precession rate to a precision well exceeding the level predicted by general relativity.

  5. 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?

  6. 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?

  7. The Circumstellar Imager: Direct detection of extra-solar planetary systems

    NASA Technical Reports Server (NTRS)

    Ftaclas, Christ; Nonnenmacher, Andreas L.; Terrile, Richard J.; Pravdo, Steven H.; Gatewood, George D.; Levy, Eugene

    1994-01-01

    The Astrometric Imaging Telescope (AIT) is designed to probe the circumstellar environment by both direct imaging and indirect astrometric measurements. The Circumstellar Imager (CI) is a coronagraphic camera and is the direct imaging component of the AIT. The CI is designed to obtain high-sensitivity images of the circumstellar region. It provides crucial non-inferential information relating to the frequency, origin, and evolution of planetary systems and all forms of circumstellar matter. Such imaging is usually limited by the scattered and diffracted light halos of the star itself, which are greatly suppressed in the CI by mating a novel high-efficiency coronagraph with a phase-compensated optical system. For faint point sources in the circumstellar region, the CI will have a sensitivity in excess of 5 magnitudes fainter than the as-designed Hubble Space Telescope (HST). Laboratory data are shown for the coronagraph, which, in a diffraction-limited environment, is capable of suppressing the stellar diffraction sidelobes by several orders of magnitude without significant sacrifice of field of view. In order to realize the high rejection levels inherent in the coronagraph design, it is necessary to limit scatter in the optical systems, imposing a mid-spatial frequency figure error requirement an order of magnitude smaller than that of the HST. Experimental data directed toward meeting this requirement are also shown.

  8. AN ANALYTIC RADIATIVE-CONVECTIVE MODEL FOR PLANETARY ATMOSPHERES

    SciTech Connect

    Robinson, Tyler D. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Catling, David C., E-mail: robinson@astro.washington.edu [Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 (United States)

    2012-09-20

    We present an analytic one-dimensional radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power-law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric-pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries; (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation; and (3) strongly irradiated giant planets (including hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

  9. Studies on possible propagation of microbial contamination in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Dimmick, R. L.; Wolochow, H.; Chatigny, M. A.

    1975-01-01

    Maintained aerosols were studied to demonstrate the metabolism and propagation of microbes in clouds which could occur in the course of a probe of a planetary atmosphere. Bacteriophage was used as a tool to test whether the mechanisms for DNA production remain intact and functional within the airborne bacterial cell. In one test method, bacteria were mixed with coliphage in an atomizer to allow attachment before aerosolization; in another, two suspensions were atomized saperately into a common air stream prior to aerosolization. Results show that biochemical and physiological mechanisms to allow aerobic microbes to propagate in the airborne state do exist.

  10. Studying Extrasolar Planets with WFIRST

    NASA Astrophysics Data System (ADS)

    Spergel, David N.

    2014-06-01

    The WFIRST mission will be a powerful tool for studying extrasolar planets. Through observations of gravitational microlensing, the mission will probe the demographics of extrasolar planetary systems. Its coronagraph will enable imaging and spectroscopic study of nearby planets. It will also be able to complement GAIA's astrometric measurements of masses and orbits of nearby planets.

  11. Rocky Extrasolar Planetary Compositions Derived from Externally-Polluted White Dwarfs

    E-print Network

    Klein, B; Koester, D; Zuckerman, B

    2011-01-01

    We report Keck High Resolution Echelle Spectrometer data and model atmosphere analysis of two helium-dominated white dwarfs, PG1225-079 and HS2253+8023, whose heavy pollutions most likely derive from the accretion of terrestrial-type planet(esimal)s. For each system, the minimum accreted mass is ~10^22 g, that of a large asteroid. In PG1225-079, Mg, Cr, Mn, Fe and Ni have abundance ratios similar to bulk Earth values, while we measure four refractory elements, Ca, Sc, Ti and V, all at a factor of ~2-3 higher abundance than in the bulk Earth. For HS2253+8023 the swallowed material was compositionally similar to bulk Earth in being more than 85% by mass in the major element species, O, Mg, Si, and Fe, and with abundances in the distinctive proportions of mineral oxides - compelling evidence for an origin in a rocky parent body. Including previous studies we now know of four heavily polluted white dwarfs where the measured oxygen and hydrogen are consistent with the view that the parents bodies formed with littl...

  12. Electrodynamics on extrasolar giant planets

    E-print Network

    Koskinen, T T; Lavvas, P; Cho, J Y-K

    2014-01-01

    Strong ionization on close-in extrasolar giant planets 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 MHD 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 conduc...

  13. Composition/Structure/Dynamics of comet and planetary satellite atmospheres

    NASA Technical Reports Server (NTRS)

    Combi, Michael R. (Principal Investigator)

    1995-01-01

    This research program addresses two cases of tenuous planetary atmospheres: comets and Io. The comet atmospheric research seeks to analyze a set of spatial profiles of CN in comet Halley taken in a 7.4-day period in April 1986; to apply a new dust coma model to various observations; and to analyze observations of the inner hydrogen coma, which can be optically thick to the resonance scattering of Lyman-alpha radiation, with the newly developed approach that combines a spherical radiative transfer model with our Monte Carlo H coma model. The Io research seeks to understand the atmospheric escape from Io with a hybrid-kinetic model for neutral gases and plasma given methods and algorithms developed for the study of neutral gas cometary atmospheres and the earth's polar wind and plasmasphere. Progress is reported on cometary Hydrogen Lyman-alpha studies; time-series analysis of cometary spatial profiles; model analysis of the dust comae of comets; and a global kinetic atmospheric model of Io.

  14. The role of H+3 in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Miller, S.; Achilleos, N.; Ballester, G. E.; Geballe, T. R.; Joseph, R. D.; Prangé, R.; Rego, D.; Stallard, T.; Tennyson, J.; Trafton, L. M.; Waite, J. H., Jr.

    2000-09-01

    Spectroscopic studies of the upper atmospheres of the giant planets using in frared wavelengths sensitive to the H3+ molecular ion sho w that this species plays a critical role in determining the physical condition s there. For Jupiter, we propose that the recently detected H3+ electrojet holds the key to the mechanism by which the equatorial plasma sheet is kept in (partial) co-rotation with the planet, and that this mechanis m also provides a previously unconsidered source of energy that helps explain w hy the jovian thermosphere is considerably hotter than expected. For Saturn, we show that the H3+ auroral emission is ca. 1% of t hat of Jupiter because of the lower ionospheric/thermospheric temperature and t he lower flux of ionizing particles precipitated there; it is probably unnecess ary to invoke additional chemistry in the auroral/polar regions. For Uranus, we report further evidence that its emissio! n intensity is controlled by the cycle of solar activity. And we propose that H 3+ emission may just be detectable using current technolo gy from some of the giant extra-solar planets that have been detected orbiting nearby stars, such as Tau Bootes.

  15. A Spectrum of an Extrasolar Planet

    E-print Network

    L. Jeremy Richardson; Drake Deming; Karen Horning; Sara Seager; Joseph Harrington

    2007-02-20

    Of the over 200 known extrasolar planets, 14 exhibit transits in front of their parent stars as seen from Earth. Spectroscopic observations of the transiting planets can probe the physical conditions of their atmospheres. One such technique can be used to derive the planetary spectrum by subtracting the stellar spectrum measured during eclipse (planet hidden behind star) from the combined-light spectrum measured outside eclipse (star + planet). Although several attempts have been made from Earth-based observatories, no spectrum has yet been measured for any of the established extrasolar planets. Here we report a measurement of the infrared spectrum (7.5--13.2 micron) of the transiting extrasolar planet HD209458b. Our observations reveal a hot thermal continuum for the planetary spectrum, with approximately constant ratio to the stellar flux over this wavelength range. Superposed on this continuum is a broad emission peak centered near 9.65 micron that we attribute to emission by silicate clouds. We also find a narrow, unidentified emission feature at 7.78 micron. Models of these ``hot Jupiter'' planets predict a flux peak near 10 micron, where thermal emission from the deep atmosphere emerges relatively unimpeded by water absorption, but models dominated by water fit the observed spectrum poorly.

  16. Theoretical studies of important processes in planetary and comet atmospheres

    NASA Technical Reports Server (NTRS)

    Guberman, Steven L.

    1990-01-01

    Dissociative recombination (DR) reactions in planetary and comet atmospheres are discussed. A computer program was developed which determines DR cross sections and rates using potential curves and electronic capture widths. It uses Multi-Channel Quantum Defect Theory (MQDT) to include excited Rydberg resonance levels in the DR cross section and rate calculations. Each vibrational level of a molecular ion is the limit for an infinite series of Rydberg states. Above each ion vibrational level are Rydberg vibrational levels having higher ion levels as their series limit. These Rydberg vibrational levels are resonances, i.e., neutral states which are imbedded in the electron-molecular ion continuum. The process in which the Rydberg level causes an abrupt perturbation in the cross section for DR (because of interference between capture into the Rydberg level and capture into the repulsive dissociative state) is referred to as indirect recombination. The process in which the Rydberg levels are excluded and recombination goes from the entrance channel to the repulsive state is called direct recombination. The full DR process, i.e., both direct and indirect recombination, is the process of importance for planetary atmospheres. These ideas are illustrated with the new results for DR from excited ion vibrational levels of O2(+) into the dissociative state which leads to O(1S) + O(1D).

  17. Atmospheric circulation modeling of super Earths and terrestrial extrasolar planets using the SPARC/MITgcm

    NASA Astrophysics Data System (ADS)

    Kataria, T.; Showman, A. P.; Haberle, R. M.; Marley, M. S.; Fortney, J. J.; Freedman, R. S.

    2013-12-01

    The field of exoplanets continues to be a booming field of research in astronomy and planetary science, with numerous ground-based (e.g., SuperWASP, HARPS-N and S) and space-based surveys (e.g., Kepler) that detect and characterize planets ranging from hot Jupiters, Jovian-sized planets orbiting less than 0.1 AU from their star, to super Earths and terrestrial exoplanets, planets that have masses equal to or less than 10 times that of Earth with a range of orbital distances. Atmospheric circulation modeling plays an important role in the characterization of these planets, helping to constrain observations that probe their atmospheres. These models have proven successful in understanding observations of transiting exoplanets (when the planet passes in front of the star along our line of sight) particularly when the planet is passing through secondary eclipse (when the planet's dayside is visible). In modeling super Earths and terrestrial exoplanets, we must consider not only planets with thick fluid envelopes, but also traditional terrestrial planets with solid surfaces and thinner atmospheres. To that end, we present results from studies investigating the atmospheric circulation of these classes of planets using the SPARC/MITgcm, a state-of-the-art model which couples the MIT General Circulation Model with a plane-parallel, two-stream, non-gray radiative transfer model. We will present results from two studies, the first focusing on the circulation of GJ 1214b, a super-Earth detected by the MEarth ground-based survey, and a second study which explores the circulation of terrestrial exoplanets orbiting M-dwarfs.

  18. Data Assimilation and Data Fusion for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Houben, Howard

    2005-01-01

    The overarching goal of this Cooperative Agreement was to develop a model and procedures for the data assimilation of planetary spacecraft atmospheric observations. Data assimilation - in its application to weather analysis and prediction - is the process of finding an initial state of the meteorological variables (winds, temperatures, pressures, etc.) of an atmosphere, which, when propagated forward in time using a deterministic general circulation model, reproduces all of the available observations over that time to within the measurement and computational errors. With this definition, data assimilation is seen to be a natural extension of well-known least-squares minimization techniques. The primary complication arises from the scale of the problem: For the Martian atmosphere with the available nadir-viewing Thermal Emission Spectrometer data from Mars Global Surveyor, approximately 1,000,000 individual measurements of channel radiances (in the 15-micrometer region, where these radiances relate directly to the surface and atmospheric temperature) were made per day. A suitable general circulation model for dealing with this data set has on the order of 20,000 independent variables. After some spatial and temporal averaging of the data - which provides a necessary statistical estimate of the representativeness of the measurements, a crucial issue in data assimilation - the problem reduces in scale to the solution of approximately 50,000 equations for the 20,000 variables.

  19. Continuing Studies in Support of Ultraviolet Observations of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Clark, John

    1997-01-01

    This program was a one-year extension of an earlier Planetary Atmospheres program grant, covering the period 1 August 1996 through 30 September 1997. The grant was for supporting work to complement an active program observing planetary atmospheres with Earth-orbital telescopes, principally the Hubble Space Telescope (HST). The recent concentration of this work has been on HST observations of Jupiter's upper atmosphere and aurora, but it has also included observations of Io, serendipitous observations of asteroids, and observations of the velocity structure in the interplanetary medium. The observations of Jupiter have been at vacuum ultraviolet wavelengths, including imaging and spectroscopy of the auroral and airglow emissions. The most recent HST observations have been at the same time as in situ measurements made by the Galileo orbiter instruments, as reflected in the meeting presentations listed below. Concentrated efforts have been applied in this year to the following projects: The analysis of HST WFPC 2 images of Jupiter's aurora, including the Io footprint emissions. We have performed a comparative analysis of the lo footprint locations with two magnetic field models, studied the statistical properties of the apparent dawn auroral storms on Jupiter, and found various other repeated patterns in Jupiter's aurora. Analysis and modeling of airglow and auroral Ly alpha emission line profiles from Jupiter. This has included modeling the aurora] line profiles, including the energy degradation of precipitating charged particles and radiative transfer of the emerging emissions. Jupiter's auroral emission line profile is self-absorbed, since it is produced by an internal source, and the resulting emission with a deep central absorption from the overlying atmosphere permits modeling of the depth of the emissions, plus the motion of the emitting layer with respect to the overlying atmospheric column from the observed Doppler shift of the central absorption. By contrast the airglow emission line, which is dominated by resonant scattering of solar emission, has no central absorption, but displays rapid time variations and broad wings, indicative of a superthermal component (or corona) in Jupiter's upper atmosphere. Modeling of the observed motions of the plumes produced after the impacts of the fragments of Comet S/L-9 with Jupiter in July 1994, from the HST WFPC 2 imaging series.

  20. Characterization of Extrasolar Planets with JWST\\/NIRSpec

    Microsoft Academic Search

    J. A. Valenti; S. Arribas; P. Ferruit; R. Gilliland; T. Boeker; A. Bunker; S. Charlot; D. Crampton; G. de Marchi; M. Franx; P. Jakobsen; R. Maiolino; H. Moseley; B. Rauscher; M. Regan; H. W. Rix

    2005-01-01

    We explore the potential of the Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) to characterize extrasolar planets around cool stars. NIRSpec will be able to study the temperature and composition of planetary atmospheres by separating the thermal emission spectrum (0.1%) of known short-period planets from the emission spectrum (99.9%) of their host stars. Separation of the two

  1. Extrasolar planets and brown dwarfs around A-F type stars V. A planetary system found with HARPS around the F6IV-V star HD 60532

    E-print Network

    M. Desort; A. -M. Lagrange; F. Galland; H. Beust; S. Udry; M. Mayor; G. Lo Curto

    2008-09-23

    Aims: In the frame of the search for extrasolar planets and brown dwarfs around early-type stars, we present the results obtained for the F-type main-sequence star HD 60532 (F6V) with HARPS. Methods: Using 147 spectra obtained with HARPS at La Silla on a time baseline of two years, we study the radial velocities of this star. Results: HD 60532 radial velocities are periodically variable, and the variations have a Keplerian origin. This star is surrounded by a planetary system of two planets with minimum masses of 1 and 2.5 Mjup and orbital separations of 0.76 and 1.58 AU respectively. We also detect high-frequency, low-amplitude (10 m/s peak-to-peak) pulsations. Dynamical studies of the system point toward a possible 3:1 mean-motion resonance which should be confirmed within the next decade.

  2. Meteoric Ablation in Planetary Atmospheres and the Laboratory

    NASA Astrophysics Data System (ADS)

    Sternovsky, Z.; Robertson, S. H.; Horanyi, M.; Szalay, J.

    2013-12-01

    The chemistry and energetics of all planetary atmospheres are influenced by the influx of interplanetary dust particles and the layers of material deposited through ablation. Even for the well-monitored terrestrial atmosphere, the amount of the incoming cosmic material remains uncertain. Radar and lidar systems make valuable measurements of the incoming particles and the atomic and ion layers, as well as the particulate remnants. However, the measurement methods are biased due to the wide ranges of mass, velocity and composition of the incoming material. Further ambiguity is introduced through the uncertainty of some of the ablation parameters, e.g., the ionization probability. Laboratory measurements can be used to benchmark the ablation of different materials over a wide range of speeds. In this talk, we give and overview of the state of the art ablation models and the applicability of laboratory measurements to verify these models and how fundamental quantities can be measured, including ionization and luminous efficiencies. There are upcoming mission to Mars (MAVEN) and Pluto (New Horizons) that are expected to return data on the distribution of the ablated material and the effect on their atmospheres. These data could potentially be used to further constrain the ablation processes and the parameters used.

  3. Construction of an advanced software tool for planetary atmospheric modeling

    NASA Technical Reports Server (NTRS)

    Friedland, Peter; Keller, Richard M.; Mckay, Christopher P.; Sims, Michael H.; Thompson, David E.

    1992-01-01

    Scientific model-building can be a time intensive and painstaking process, often involving the development of large complex computer programs. Despite the effort involved, scientific models cannot be distributed easily and shared with other scientists. In general, implemented scientific models are complicated, idiosyncratic, and difficult for anyone but the original scientist/programmer to understand. We propose to construct a scientific modeling software tool that serves as an aid to the scientist in developing, using and sharing models. The proposed tool will include an interactive intelligent graphical interface and a high-level domain-specific modeling language. As a test bed for this research, we propose to develop a software prototype in the domain of planetary atmospheric modeling.

  4. Hydrogen atom initiated chemistry. [chemical evolution in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hong, J. H.; Becker, R. S.

    1979-01-01

    H Atoms have been created by the photolysis of H2S. These then initiated reactions in mixtures involving acetylene-ammonia-water and ethylene-ammonia-water. In the case of the acetylene system, the products consisted of two amino acids, ethylene and a group of primarily cyclic thio-compounds, but no free sulfur. In the case of the ethylene systems, seven amino acids, including an aromatic one, ethane, free sulfur, and a group of solely linear thio-compounds were produced. Total quantum yields for the production of amino acids were about 3 x 10 to the -5th and about 2 x 10 to the -4th with ethylene and acetylene respectively as carbon substrates. Consideration is given of the mechanism for the formation of some of the products and implications regarding planetary atmosphere chemistry, particularly that of Jupiter, are explored.

  5. How do Atmospheres Affect Planetary Temperatures: Activity A How do Atmospheres Interact with Solar Energy?

    NSDL National Science Digital Library

    2012-08-03

    In this 2-part inquiry-based lesson, students conduct a literature search to determine the characteristics of the atmospheres of different planets (Venus, Mercury, Mars and Earth). After collecting and analyzing data, student teams design and conduct a controlled physical experiment using a lab apparatus to learn about the interaction of becomes CO², air, and temperature. The resource includes student worksheets, a design proposal, and student questions. Connections to contemporary climate change are addressed. This lesson is the first of four in Topic 4, "How do Atmospheres Affect Planetary Temperatures?" within the resource, Earth Climate Course: What Determines a Planet's Climate?

  6. Biomarkers of extrasolar planets and their observability

    NASA Astrophysics Data System (ADS)

    Selsis, Franck; Paillet, Jimmy; Allard, France

    The first space-borne instruments able to detect and characterize extrasolar terrestrial planets, Darwin (ESA) and TPF-C (Terrestrial Planet Finder-Coronograph, NASA), should be launched at the end of the next decade. Beyond the challenge of planet detection itself, the ability to measure mid-infrared (Darwin) and visible (TPF-C) spectra at low resolution will allow us to characterize the exoplanets discovered. The spectral analysis of these planets will extend the field of planetary science beyond the Solar System to the nearby Universe: It will give access to certain planetary properties (albedo, brightness temperature, radius) and reveal the presence of atmospheric compounds, which, together with the radiative budget of the planet, will provide the keys to understanding how the climate system works on these worlds. If terrestrial planets are sufficiently abundant, these missions will collect data for numerous planetary systems of different ages and orbiting different types of stars. Theories for the formation, evolution and habitability of the terrestrial planets will at last face the test observation. The most fascinating perspective offered by these space observatories is the ability to detect spectral signatures indicating biological activity. In this chapter, we review and discuss the concept of extrasolar biosignatures or biomarkers. We focus mainly on the identification of oxygen-rich atmospheres through the detection of O2 and O3 features, addressing also the case of other possible biomarkers and indicators of habitability.

  7. The Explicit Planetary Isentropic-Coordinate (EPIC) Atmospheric Model

    NASA Astrophysics Data System (ADS)

    Dowling, T. E.; Fischer, A. S.; Gierasch, P. J.; Harrington, J.; LeBeau, R. P.; Santori, C. M.

    1998-04-01

    We describe a new general circulation model (GCM) designed for planetary atmospheric studies called the EPIC model. This is a finite-difference model based on the isentropic-coordinate scheme of Hsu and Arakawa (1990.Mon. Wea. Rev.118, 1933-1959). We report on previously undocumented modifications, additions, and key practical issues that experience running the model has revealed to be important. The model integrates the hydrostatic primitive equations, which are valid for large-scale atmospheric dynamics and include gravity waves (buoyancy waves), planetary waves (Rossby waves), and horizontally propagating sound waves (Lamb waves), but not vertically propagating sound waves because of the hydrostatic approximation. The vertical coordinate is entropy in the form of potential temperature, which coincides with material surfaces for adiabatic motion. This means that there is no vertical velocity except where there is heating, which improves accuracy and helps the model maintain conservation properties over long integrations. An isentropic vertical coordinate is natural for the atmospheres of Jupiter, Saturn, Uranus, and Neptune, which are believed to have essentially adiabatic interiors that match up with the bottom of the model and is also excellent for middle-atmosphere studies on any planet. Radiative processes are parameterized by Newtonian cooling, and the latent heat of ortho-para hydrogen conversion is included when appropriate, with a suitably defined mean potential temperature. The model is written with general map factors that make it easy to configure in oblate spherical, cylindrical, or Cartesian coordinates. The code includes optional Message Passing Interface (MPI) library calls and hence runs on any Unix-based parallel computer or network cluster. An optional graphical user interface to commercial visualization software facilitates control of the model and analysis of output. Memory is allocated dynamically such that the user does not recompile to change horizontal or vertical resolution or range. Applications to date include comet impact forecasts and hindcasts for Jupiter, meridional circulation studies of Uranus and Neptune, and the accompanying paper on three-dimensional simulations of Neptune's Great Dark Spot (1998.Icarus132, 239-265).

  8. Detection of the Magnetospheric Emissions from Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Lazio, J.

    2014-12-01

    Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. These internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind, a planet's magnetic field can produce electron cyclotron masers in its magnetic polar regions. The most well known example of this process is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior as well as improved understanding of the basic planetary dynamo process. The magnetospheric emissions from solar system planets and the discovery of extrasolar planets have motivated both theoretical and observational work on magnetospheric emissions from extrasolar planets. Stimulated by these advances, the W.M. Keck Institute for Space Studies hosted a workshop entitled "Planetary Magnetic Fields: Planetary Interiors and Habitability." I summarize the current observational status of searches for magnetospheric emissions from extrasolar planets, based on observations from a number of ground-based radio telescopes, and future prospects for ground-based studies. Using the solar system planetary magnetic fields as a guide, future space-based missions will be required to study planets with magnetic field strengths lower than that of Jupiter. I summarize mission concepts identified in the KISS workshop, with a focus on the detection of planetary electron cyclotron maser emission. The authors acknowledge ideas and advice from the participants in the "Planetary Magnetic Fields: Planetary Interiors and Habitability" workshop organized by the Keck Institute for Space Studies. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

  9. Physico-Chemistry of Planetary Atmospheric Entry Plasmas

    NASA Astrophysics Data System (ADS)

    Bultel, Arnaud; Annaloro, Julien; Morel, Vincent

    2012-11-01

    This contribution deals with the description of the physico-chemistry in the reactive flow produced near the surface of a body entering a planetary atmosphere in hypersonic regime. A shock layer is formed in which a boundary layer is developed where energy is released to the body surface. N2 is chosen as a test-case of Earth atmospheric reentry to illustrate the main characteristics of the flow. The vibrational and electronic specific Collisional-Radiative model CoRaM-N2 is described and implemented in a one-dimensional Euler flow solver. The well-known FIRE II flight experiment conditions are used to illustrate the behaviour of the different ground and excited states of atomic and molecular species. The results show that the three successive phases occur: vibrational excitation, dissociation and ionisation. Radiation plays a minor role. According to the upstream thermodynamic conditions, the boundary layer edge can be in local thermodynamic equilibrium or not. The different strategies using thermal protection systems are discussed to reduce the damaging of the entering body.

  10. Theory for the Secondary Eclipse Fluxes, Spectra, Atmospheres, and Light Curves of Transiting Extrasolar Giant Planets

    Microsoft Academic Search

    A. Burrows; D. Sudarsky; I. Hubeny

    2006-01-01

    We have created a general methodology for calculating the wavelength-dependent light curves of close-in extrasolar giant planets (EGPs) as they traverse their orbits. Focusing on the transiting EGPs HD 189733b, TrES-1, and HD 209458b, we calculate planet\\/star flux ratios during secondary eclipse and compare them with the Spitzer data points obtained so far in the mid-infrared. We introduce a simple

  11. 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 of its chromosphere.

  12. Probing the extreme planetary atmosphere of WASP-12b Mark Swain a,

    E-print Network

    Probing the extreme planetary atmosphere of WASP-12b Mark Swain a, , Pieter Deroo a , Giovanna of the exoplanet WASP-12b obtained using the HST WFC3 instrument. The disk-aver- age dayside brightness temperature for C/O > 1 in the atmosphere of WASP-12b. Assuming a physically plausible atmosphere, we find evidence

  13. Atmospheric Eclipses Now and Then: Probes of Stellar and Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Guinan, Edward F.; Engle, S. G.; Recker, G.; Kullberg, E.

    2013-07-01

    Eclipses have played major roles in the development of Astronomy from antiquity up the present time. Lunar eclipses first showed that the Earth is sphere and solar eclipses revealed the Sun's chromosphere and corona. More recently a wealth of important astrophysical data has been gleamed from eclipsing binary stars and from planetary transits and occultations within our solar system and from transiting exoplanets orbiting other stars. Since the 1930s a small number of long-period eclipsing binary systems consisting of supergiant (or giant) primary stars and smaller hotter (typically B-type) companions - such as zeta Aur, 31 Cyg ,32 Cyg & VV Cep were found to undergo "atmospheric" eclipses. Atmospheric eclipses arise as the light of the small hot stars passes through the extended outer atmospheres of their K - M supergiant companions shortly before and after the primary eclipses. Also included with these systems is the 27-yr eclipsing binary eps Aur which consists of an F-supergiant and large, cool disk object. These stars are important astrophysical laboratories in which the atmospheric eclipses permit the extent and structure of the outer atmospheres of cool supergiants to be probed. In more recent years the powerful technique of atmospheric eclipses has been extended to short period white dwarf/cool star eclipsing binaries (e.g.-V471 Tau) as well as rare eclipsing binary systems with Cepheid components. Also during the last decade, the technique has been extended to transiting exoplanets in which the "transmission spectrum" of the exoplanet is studied as the light of star passes through the planet's atmosphere during the transit eclipse. These studies have revealed water vapor, CH4, CO2 and Na and other elements and molecules in exoplanet's atmospheres. An overview will be given with emphasis on some recent developments. This research is supported by grants from NSF/RUI and HST/NASA.

  14. Extrasolar Planets

    Microsoft Academic Search

    P. Butler

    2003-01-01

    None of the roughly one hundred hundred extrasolar planets found to date closely resembles the Solar System. Unlike the Solar System, most extrasolar planets are in eccentric orbits. The giant planets in the Solar System all orbit beyond 5 AU, while the known extrasolar planets (with one exception) all orbit within 4 AU, with several in extraordinarily small orbits with

  15. Frequency Analysis and Extrasolar Planets

    Microsoft Academic Search

    Maciej Konacki; Andrzej J. Maciejewski

    1999-01-01

    \\u000a The discovery [13] (and confirmation [14]) of the first extrasolar planetary system by Wolszczan & Frail (1991) around the pulsar B1257+12 began a new era in this\\u000a exciting field of astronomy. A few years later, in 1995, the first extrasolar planet around a normal star was found by Queloz\\u000a & Mayor [10]. This was followed by other such discoveries [9].

  16. Effects of the seasonal cycle on superrotation in planetary atmospheres

    SciTech Connect

    Mitchell, Jonathan L. [Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA 90095 (United States); Vallis, Geoffrey K. [College of Engineering, Mathematics and Physical Science, Exeter University, Exeter (United Kingdom); Potter, Samuel F. [Atmospheric and Oceanic Sciences Program, Princeton University, NJ 08544 (United States)

    2014-05-20

    The dynamics of dry atmospheric general circulation model simulations forced by seasonally varying Newtonian relaxation are explored over a wide range of two control parameters and are compared with the large-scale circulation of Earth, Mars, and Titan in their relevant parameter regimes. Of the parameters that govern the behavior of the system, the thermal Rossby number (Ro) has previously been found to be important in governing the spontaneous transition from an Earth-like climatology of winds to a superrotating one with prograde equatorial winds, in the absence of a seasonal cycle. This case is somewhat unrealistic as it applies only if the planet has zero obliquity or if surface thermal inertia is very large. While Venus has nearly vanishing obliquity, Earth, Mars, and Titan (Saturn) all have obliquities of ?25° and varying degrees of seasonality due to their differing thermal inertias and orbital periods. Motivated by this, we introduce a time-dependent Newtonian cooling to drive a seasonal cycle using idealized model forcing, and we define a second control parameter that mimics non-dimensional thermal inertia of planetary surfaces. We then perform and analyze simulations across the parameter range bracketed by Earth-like and Titan-like regimes, assess the impact on the spontaneous transition to superrotation, and compare Earth, Mars, and Titan to the model simulations in the relevant parameter regime. We find that a large seasonal cycle (small thermal inertia) prevents model atmospheres with large thermal Rossby numbers from developing superrotation by the influences of (1) cross-equatorial momentum advection by the Hadley circulation and (2) hemispherically asymmetric zonal-mean zonal winds that suppress instabilities leading to equatorial momentum convergence. We also demonstrate that baroclinic instabilities must be sufficiently weak to allow superrotation to develop. In the relevant parameter regimes, our seasonal model simulations compare favorably to large-scale, seasonal phenomena observed on Earth and Mars. In the Titan-like regime the seasonal cycle in our model acts to prevent superrotation from developing, and it is necessary to increase the value of a third parameter—the atmospheric Newtonian cooling time—to achieve a superrotating climatology.

  17. Extrasolar Planet Orbits and Eccentricities

    E-print Network

    Scott Tremaine; Nadia L. Zakamska

    2003-12-01

    The known extrasolar planets exhibit many interesting and surprising features--extremely short-period orbits, high-eccentricity orbits, mean-motion and secular resonances, etc.--and have dramatically expanded our appreciation of the diversity of possible planetary systems. In this review we summarize the orbital properties of extrasolar planets. One of the most remarkable features of extrasolar planets is their high eccentricities, far larger than seen in the solar system. We review theoretical explanations for large eccentricities and point out the successes and shortcomings of existing theories.

  18. Analytic theory of orbit contraction and ballistic entry into planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Longuski, J. M.; Vinh, N. X.

    1980-01-01

    A space object traveling through an atmosphere is governed by two forces: aerodynamic and gravitational. On this premise, equations of motion are derived to provide a set of universal entry equations applicable to all regimes of atmospheric flight from orbital motion under the dissipate force of drag through the dynamic phase of reentry, and finally to the point of contact with the planetary surface. Rigorous mathematical techniques such as averaging, Poincare's method of small parameters, and Lagrange's expansion, applied to obtain a highly accurate, purely analytic theory for orbit contraction and ballistic entry into planetary atmospheres. The theory has a wide range of applications to modern problems including orbit decay of artificial satellites, atmospheric capture of planetary probes, atmospheric grazing, and ballistic reentry of manned and unmanned space vehicles.

  19. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1992-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The use of theoretically derived microwave absorption properties for such atmospheric constituents, or using laboratory measurements of such properties under environmental conditions which are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. The recognition of the need to make such laboratory measurements of simulated planetary atmospheres over a range of temperatures and pressures which correspond to the altitudes probed by both radio occultation experiments and radio astronomical observations, and over a range of frequencies which correspond to those used in both radio occultation experiments and radio astronomical observations, has led to the development of a facility at Georgia Tech which is capable of making such measurements. The goal of this investigation was to conduct such measurements and to apply the results to a wide range of planetary observations, both spacecraft and earth-based, in order to determine the identity and abundance profiles of constituents in those planetary atmospheres.

  20. Validation of Atmospheric Dynamics (VADY) - connections between planetary waves and atmospheric circulation types

    NASA Astrophysics Data System (ADS)

    Lang, Benjamin; Jacobeit, Jucundus; Beck, Christoph; Philipp, Andreas

    2015-04-01

    The climate research program "Medium-range Climate Predictions" (MiKlip), funded by the Federal Ministry of Education and Research in Germany (BMBF), has the aim to develop a climate model system (MPI-ESM) that can provide reliable decadal predictions of climate, including extreme weather events. A substantial part of the development process is a comprehensive model validation. Within MiKlip, it includes comparisons of model simulations and observations in order to allow statements about the performance of the model and to give particular recommendations for the further development of the model. The research project "Validation of Atmospheric Dynamics" (VADY), conducted by the cooperation partners "Institute of Geography at the University of Augsburg" (IGUA) and the "German Aerospace Centre" (DLR), contributes to model validation within MiKlip with a special focus on atmospheric waves and circulation dynamics. Within the framework of VADY, DLR validates the representation of atmospheric waves on different levels and scales based on suitable activity indices (e.g. the so-called large-scale dynamical activity index (LDAI), which is a measure for the activity of planetary waves). The focus of IGUA is on the model validation with respect to the representation of atmospheric circulation types, dynamical modes and the teleconnectivity of the atmospheric circulation. Currently, the connection between LDAI and atmospheric circulation types on different levels and for different seasons in the North Atlantic-European region is analysed by considering, in particular, the North Atlantic Oscillation. Results will be shown for the connection between LDAI and atmospheric circulation types and subsequently for the representation of the identified connections in the decadal-prediction model system of MPI-ESM.

  1. The HARPS search for southern extra-solar planets XXXV. Planetary systems and stellar activity of the M dwarfs GJ 3293, GJ 3341, and GJ 3543

    E-print Network

    Astudillo-Defru, N; Delfosse, X; Segransan, D; Forveille, T; Bouchy, F; Gillon, M; Lovis, C; Mayor, M; Neves, V; Pepe, F; Perrier, C; Queloz, D; Rojo, P; Santos, N C; Udry, S

    2014-01-01

    Context. Planetary companions of a fixed mass induce larger amplitude reflex motions around lower-mass stars, which helps make M dwarfs excellent targets for extra-solar planet searches. State of the art velocimeters with $\\sim$1m/s stability can detect very low-mass planets out to the habitable zone of these stars. Low-mass, small, planets are abundant around M dwarfs, and most known potentially habitable planets orbit one of these cool stars. Aims. Our M-dwarf radial velocity monitoring with HARPS on the ESO 3.6m telescope at La Silla observatory makes a major contribution to this sample. Methods. We present here dense radial velocity (RV) time series for three M dwarfs observed over $\\sim5$ years: GJ 3293 (0.42M$_\\odot$), GJ 3341 (0.47M$_\\odot$), and GJ 3543 (0.45M$_\\odot$). We extract those RVs through minimum $\\chi^2$ matching of each spectrum against a high S/N ratio stack of all observed spectra for the same star. We then vet potential orbital signals against several stellar activity indicators, to dis...

  2. Laboratory Evaluation and Application of Microwave Absorption Properties Under Simulated Conditions for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1997-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and earth-based radio astronomical observations can be used to infer abundances of microwave absorbing constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The use of theoretically-derived microwave absorption properties for such atmospheric constituents, or using laboratory measurements of such properties under environmental conditions which are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. Laboratory measurements completed under this grant (NAGW-533), have shown that the opacity from, SO2 under simulated Venus conditions is best described by a different lineshape than was previously used in theoretical predictions. The recognition of the need to make such laboratory measurements of simulated planetary atmospheres over a range of temperatures and pressures which correspond to the altitudes probed by both radio occultation experiments and radio astronomical observations, and over a range of frequencies which correspond to those used in both radio occultation experiments and radio astronomical observations, has led to the development of a facility at Georgia Tech which is capable of making such measurements. It has been the goal of this investigation to conduct such measurements and to apply the results to a wide range of planetary observations, both spacecraft and earth-based, in order to determine the identity and abundance profiles of constituents in those planetary atmospheres.

  3. Meteoric Material - One of the Least Explored Components of Planetary Atmospheres

    Microsoft Academic Search

    J. I. Moses; J. M. Grebowsky; W. D. Pesnell; A. L. Weisman

    2001-01-01

    Interplanetary dust particles (IDPs) continuously impact all the planets and their satellites in the solar system. In all planetary atmospheres IDPs leave their imprint as aerosols or smoke particles that are left behind when the IDPs do not ablate completely or when the ablated vapors recondense. In addition, in all atmospheres they produce ionization layers comprised of metallic ions, predominantly

  4. Negative ions in the ionospheres of planetary bodies without atmospheres

    NASA Technical Reports Server (NTRS)

    Wekhof, A.

    1981-01-01

    It is noted that negative ions may be formed in the ionospheres of Mercury, the moon, and Jupiter's satellites with densities of a few percent of the ionospheric electron density. Negative ions result from three mechanisms at the planetary surface: charge inversion during energetic proton scattering, with simultaneous secondary negative ion emission, and micrometeorite impacts. The density and distribution of negative ions around planetary bodies depends primarily on the negative ion lifetimes determined through photodetachment by solar radiation.

  5. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1987-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and Earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorping properties of potential constituents is available. The use of theoretically derived microwave absorption properties for such atmospheric constituents, or laboratory measurements of such properties under environmental conditions which are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. Laboratory measurement of the microwave properties of atmospheric gases under simulated conditions for the outer planets were conducted. Results of these measurements are discussed.

  6. Seeing the Invisible: Educating the Public on Planetary Magnetic Fields and How they Affect Atmospheres

    NASA Astrophysics Data System (ADS)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Schultz, G.; Yan, D.; Guevara, S.; Randol, S.

    2010-08-01

    Magnetic fields and charged particles are difficult for school children, the general public, and scientists alike to visualize. But studies of planetary magnetospheres and ionospheres have broad implications for planetary evolution, from the deep interior to the ancient climate, that are important to communicate to each of these audiences. This presentation will highlight the visualization materials that we are developing to educate audiences on the magnetic fields of planets and how they affect the atmosphere. The visualization materials that we are developing consist of simplified data sets that can be displayed on spherical projection systems and portable 3-D rigid models of planetary magnetic fields.

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

    SciTech Connect

    Kobayashi, Hiroshi; Krivov, Alexander V. [Astrophysical Institute and University Observatory, Friedrich Schiller University, Schillergaesschen 2-3, 07745 Jena (Germany); Tanaka, Hidekazu, E-mail: hkobayas@astro.uni-jena.de [Institute of Low Temperature Science, Hokkaido University, Kita-Ku Kita 19 Nishi 8, Sapporo 060-0819 (Japan)

    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).

  8. An extended upper atmosphere around the extrasolar planet HD209458b

    Microsoft Academic Search

    A. Vidal-Madjar; A. Lecavelier des Etangs; J.-M. Désert; G. E. Ballester; R. Ferlet; G. Hébrard; M. Mayor

    2003-01-01

    The planet in the system HD209458 is the first one for which repeated transits across the stellar disk have been observed. Together with radial velocity measurements, this has led to a determination of the planet's radius and mass, confirming it to be a gas giant. But despite numerous searches for an atmospheric signature, only the dense lower atmosphere of HD209458b

  9. 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

  10. Abundances of refractory elements in the atmospheres of stars with extrasolar planets

    E-print Network

    G. Gilli; G. Israelian; A. Ecuvillon; N. C. Santos; M. Mayor

    2005-12-08

    This work presents a uniform and homogeneous study of chemical abundances of refractory elements in 101 stars with and 94 without known planetary companions. We carry out an in-depth investigation of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Na, Mg and Al. The new comparison sample, spanning the metallicity range -0.70< [Fe/H]< 0.50, fills the gap that previously existed, mainly at high metallicities, in the number of stars without known planets. We used an enlarged set of data including new observations, especially for the field ``single'' comparison stars. The line list previously studied by other authors was improved: on average we analysed 90 spectral lines in every spectrum and carefully measured more than 16600 equivalent widths (EW) to calculate the abundances. We investigate possible differences between the chemical abundances of the two groups of stars, both with and without planets. The results are globally comparable to those obtained by other authors, and in most cases the abundance trends of planet-host stars are very similar to those of the comparison sample. This work represents a step towards the comprehension of recently discovered planetary systems. These results could also be useful for verifying galactic models at high metallicities and consequently improve our knowledge of stellar nucleosynthesis and galactic chemical evolution.

  11. INTERACTION OF THE SOLAR WIND WITH PLANETARY ATMOSPHERES

    Microsoft Academic Search

    Richard A. Elco

    1969-01-01

    Neither Venus nor the moon have a significant dipole magnetic field, and their atmospheres are exposed to the solar wind and the interplanetary magnetic field. As the solar wind ions penetrate the atmosphere, photo and charge-exchange ionization reactions alter the density and velocity of the ion stream. A collisionless reacting hydromagnetic model is used to describe the flow of atmospheric

  12. Planetary Atmospheres Earth and the Other Terrestrial Worlds

    E-print Network

    Crenshaw, Michael

    of molecular nitrogen (N2 - 78%) and oxygen (O2 - 21%) Atmospheric Pressure Gas pressure depends on both increases the pressure. #12;2 Atmospheric Pressure · Pressure and density decrease with altitude because of Atmospheres · Create pressure that determines whether liquid water can exist on surface · Absorb and scatter

  13. Laboratory measurements of microwave and millimeter-wave properties of planetary atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1989-01-01

    Accurate data on microwave and millimeter-wave properties of potential planetary atmospheric constituents is critical for the proper interpretation of radio occultation measurements, and of radio astronomical observations of both continuum and spectral line emissions. Such data is also needed to correct for atmospheric effects on radar studies of surface reflectivity. Since the refractive and absorptive properties of atmospheric constituents often vary drastically from theoretically-predicted profiles, especially under the extreme conditions characteristic of the planetary atmosphere, laboratory measurements under simulated planetary conditions are required. This paper reviews the instrumentation and techniques used for laboratory measurement of the refractivity and absorptivity of atmospheric constituents at wavelengths longward of 1 mm, under simulated planetary conditions (temperature, pressure, and broadening gases). Techniques for measuring both gases and condensates are considered. Also reviewed are the relative accuracies of the various techniques. Laboratory measurements are reviewed which have already been made, and additional measurements which are needed for interpretation of data from Venus and the outer planets, are highlighted.

  14. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1989-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. Work performed has shown that laboratory measurements of the millimeter-wave opacity of ammonia between 7.5 mm and 9.3 mm and also at the 3.2 mm wavelength require a different lineshape to be used in the theoretical prediction for millimeter-wave ammonia opacity than was previously used. The recognition of the need to make such laboratory measurements of simulated planetary atmospheres over a range of temperatures and pressures which correspond to the altitudes probed by both radio occultation experiments and radio astronomical observations, and over a range of frequencies which correspond to those used in both radio occultation experiments and radio astronomical observations, has led to the development of a facility at Georgia Tech which is capable of making such measurements. It has been the goal of this investigation to conduct such measurements and to apply the results to a wide range of planetary observations, both spacecraft and earth-based, in order to determine the identity and abundance profiles of constituents in those planetary atmospheres.

  15. Laboratory Evaluation and Application of Microwave Absorption Properties under Simulated Conditions for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    2002-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments, entry probe radio signal absorption measurements, and earth-based or spacecraft-based radio astronomical (emission) observations can be used to infer abundances of microwave absorbing constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The use of theoretically-derived microwave absorption properties for such atmospheric constituents, or the use of laboratory measurements of such properties taken under environmental conditions that are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. Laboratory measurements have shown that the centimeter-wavelength opacity from gaseous phosphine (PH3) under simulated conditions for the outer planets far exceeds that predicted from theory over a wide range of temperatures and pressures. This fundamentally changed the resulting interpretation of Voyager radio occultation data at Saturn and Neptune. It also directly impacts planning and scientific goals for study of Saturn's atmosphere with the Cassini Radio Science Experiment and the Rossini RADAR instrument. The recognition of the need to make such laboratory measurements of simulated planetary atmospheres over a range of temperatures and pressures which correspond to the altitudes probed by both radio occultation experiments and radio astronomical observations, and over a range of frequencies which correspond to those used in both spacecraft entry probe and orbiter (or flyby) radio occultation experiments and radio astronomical observations, has led to the development of a facility at Georgia Tech which is capable of making such measurements. It has been the goal of this investigation to conduct such measurements and to apply the results to a wide range of planetary observations, both spacecraft- and earth-based, in order to determine the identity and abundance profiles of constituents in those planetary atmospheres,

  16. Laboratory Evaluation and Application of Microwave Absorption Properties under Simulated Conditions for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    2005-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments, entry probe radio signal absorption measurements, and earth- based or spacecraft-based radio astronomical (emission) observations can be used to infer abundances of microwave absorbing constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The use of theoretically-derived microwave absorption properties for such atmospheric constituents, or the use of laboratory measurements of such properties taken under environmental conditions that are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. For example, new laboratory measurements completed recently by Mohammed and Steffes (2003 and 2004) under this grant (NAG5-12122,5/1/02-4/30/05), have shown that the millimeter-wavelength opacities from both gaseous phosphine (PH3) and gaseous ammonia ("3) under simulated conditions for the outer planets vary significantly from that predicted by theory over a wide range of temperatures and pressures. These results have directly impacted planning and scientific goals for study of Saturn's atmosphere with the Cassini Radio Science Experiment, as discussed below. The recognition of the need to make such laboratory measurements of simulated planetary atmospheres over a range of temperatures and pressures which correspond to the altitudes probed by both radio occultation experiments and radio astronomical observations, and over a range of frequencies which correspond to those used in both spacecraft entry probe and orbiter (or flyby) radio occultation experiments and radio astronomical observations, has led to the development of a facility at Georgia Tech which is capable of making such measurements. It has been the goal of this investigation to conduct such measurements and to apply the results to a wide range of planetary observations, both spacecraft and earth-based, in order to determine the identity and abundance profiles of constituents in those planetary atmospheres.

  17. Extrasolar Planet Science with the Antarctic Planet Interferometer

    E-print Network

    Lloyd, James P.

    Extrasolar Planet Science with the Antarctic Planet Interferometer James P. Lloyda, Ben F. Lanea. The unique properties of the polar atmosphere can be exploited for Extrasolar Planet studies on the properties of the atmosphere at the South Pole and other Antarctic plateau sites for Extrasolar Planet

  18. The effect of carbon monoxide on planetary haze formation

    SciTech Connect

    Hörst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

    2014-01-20

    Organic haze plays a key role in many planetary processes ranging from influencing the radiation budget of an atmosphere to serving as a source of prebiotic molecules on the surface. Numerous experiments have investigated the aerosols produced by exposing mixtures of N{sub 2}/CH{sub 4} to a variety of energy sources. However, many N{sub 2}/CH{sub 4} atmospheres in both our solar system and extrasolar planetary systems also contain carbon monoxide (CO). We have conducted a series of atmosphere simulation experiments to investigate the effect of CO on the formation and particle size of planetary haze analogues for a range of CO mixing ratios using two different energy sources, spark discharge and UV. We find that CO strongly affects both number density and particle size of the aerosols produced in our experiments and indicates that CO may play an important, previously unexplored, role in aerosol chemistry in planetary atmospheres.

  19. The Effect of Carbon Monoxide on Planetary Haze Formation

    NASA Astrophysics Data System (ADS)

    Hörst, S. M.; Tolbert, M. A.

    2014-01-01

    Organic haze plays a key role in many planetary processes ranging from influencing the radiation budget of an atmosphere to serving as a source of prebiotic molecules on the surface. Numerous experiments have investigated the aerosols produced by exposing mixtures of N2/CH4 to a variety of energy sources. However, many N2/CH4 atmospheres in both our solar system and extrasolar planetary systems also contain carbon monoxide (CO). We have conducted a series of atmosphere simulation experiments to investigate the effect of CO on the formation and particle size of planetary haze analogues for a range of CO mixing ratios using two different energy sources, spark discharge and UV. We find that CO strongly affects both number density and particle size of the aerosols produced in our experiments and indicates that CO may play an important, previously unexplored, role in aerosol chemistry in planetary atmospheres.

  20. IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS. V. ALFVÉN IONIZATION

    SciTech Connect

    Stark, C. R.; Helling, Ch.; Rimmer, P. B. [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS (United Kingdom); Diver, D. A., E-mail: craig.stark@st-andrews.ac.uk [SUPA, School of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)

    2013-10-10

    Observations of continuous radio and sporadic X-ray emission from low-mass objects suggest they harbor localized plasmas in their atmospheric environments. For low-mass objects, the degree of thermal ionization is insufficient to qualify the ionized component as a plasma, posing the question: what ionization processes can efficiently produce the required plasma that is the source of the radiation? We propose Alfvén ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization (?10{sup –7}) that they constitute plasmas. We outline the criteria required for Alfvén ionization and demonstrate its applicability in the atmospheres of low-mass objects such as giant gas planets, brown dwarfs, and M dwarfs with both solar and sub-solar metallicities. We find that Alfvén ionization is most efficient at mid to low atmospheric pressures where a seed plasma is easier to magnetize and the pressure gradients needed to drive the required neutral flows are the smallest. For the model atmospheres considered, our results show that degrees of ionization of 10{sup –6}-1 can be obtained as a result of Alfvén ionization. Observable consequences include continuum bremsstrahlung emission, superimposed with spectral lines from the plasma ion species (e.g., He, Mg, H{sub 2}, or CO lines). Forbidden lines are also expected from the metastable population. The presence of an atmospheric plasma opens the door to a multitude of plasma and chemical processes not yet considered in current atmospheric models. The occurrence of Alfvén ionization may also be applicable to other astrophysical environments such as protoplanetary disks.

  1. On detecting biospheres from thermodynamic disequilibrium in planetary atmospheres

    E-print Network

    Krissansen-Totton, Joshua; Catling, David C

    2015-01-01

    Atmospheric chemical disequilibrium has been proposed as a method for detecting extraterrestrial biospheres from exoplanet observations. Chemical disequilibrium is potentially a generalized biosignature since it makes no assumptions about particular biogenic gases or metabolisms. Here, we present the first rigorous calculations of the thermodynamic chemical disequilibrium in the atmospheres of Solar System planets, in which we quantify the difference in Gibbs free energy of an observed atmosphere compared to that of all the atmospheric gases reacted to equilibrium. The purely gas phase disequilibrium in Earth's atmosphere, as measured by this available Gibbs free energy, is not unusual by Solar System standards and smaller than that of Mars. However, Earth's atmosphere is in contact with a surface ocean, which means that gases can react with water, and so a multiphase calculation that includes aqueous species is required. We find that the disequilibrium in Earth's atmosphere-ocean system (in joules per mole o...

  2. Outer satellite atmospheres: Their nature and planetary interactions

    NASA Technical Reports Server (NTRS)

    Smyth, W. H.; Combi, M. R.

    1984-01-01

    Significant insights regarding the nature and interactions of Io and the planetary magnetosphere were gained through modeling studies of the spatial morphology and brightness of the Io sodium cloud. East-west intensity asymmetries in Region A are consistent with an east-west electric field and the offset of the magnetic and planetary-spin axes. East-west orbital asymmetries and the absolute brightness of Region B suggest a low-velocity (3 km/sec) satellite source of 1 to 2 x 10(26) sodium atoms/sec. The time-varying spatial structure of the sodium directional features in near Region C provides direct evidence for a magnetospheric-wind-driven escape mechanism with a high-velocity (20 km/sec) source of 1 x 10(26) atoms/sec and a flux distribution enhanced at the equator relative to the poles. A model for the Io potassium cloud is presented and analysis of data suggests a low velocity source rate of 5 x 10(24) atoms/sec. To understand the role of Titan and non-Titan sources for H atoms in the Saturn system, the lifetime of hydrogen in the planetary magnetosphere was incorporated into the earlier Titan torus model of Smyth (1981) and its expected impact discussed. A particle trajectory model for cometary hydrogen is presented and applied to the Lyman-alpha distribution of Comet Kohoutek (1973XII).

  3. IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS. II. DUST-INDUCED COLLISIONAL IONIZATION

    SciTech Connect

    Helling, Ch.; Jardine, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS (United Kingdom); Mokler, F., E-mail: ch80@st-andrews.ac.uk [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr. 1, D-85748 Garching (Germany)

    2011-08-10

    Observations have shown that continuous radio emission and also sporadic H{alpha} and X-ray emission are prominent in singular, low-mass objects later than spectral class M. These activity signatures are interpreted as being caused by coupling of an ionized atmosphere to the stellar magnetic field. What remains a puzzle, however, is the mechanism by which such a cool atmosphere can produce the necessary level of ionization. At these low temperatures, thermal gas processes are insufficient, but the formation of clouds sets in. Cloud particles can act as seeds for electron avalanches in streamers that ionize the ambient gas, and can lead to lightning and indirectly to magnetic field coupling, a combination of processes also expected for protoplanetary disks. However, the precondition is that the cloud particles are charged. We use results from DRIFT-PHOENIX model atmospheres to investigate collisional processes that can lead to the ionization of dust grains inside clouds. We show that ionization by turbulence-induced dust-dust collisions is the most efficient kinetic process. The efficiency is highest in the inner cloud where particles grow quickly and, hence, the dust-to-gas ratio is high. Dust-dust collisions alone are not sufficient to improve the magnetic coupling of the atmosphere inside the cloud layers, but the charges supplied either on grains or within the gas phase as separated electrons can trigger secondary nonlinear processes. Cosmic rays are likely to increase the global level of ionization, but their influence decreases if a strong, large-scale magnetic field is present as on brown dwarfs. We suggest that although thermal gas ionization declines in objects across the fully convective boundary, dust charging by collisional processes can play an important role in the lowest mass objects. The onset of atmospheric dust may therefore correlate with the anomalous X-ray and radio emission in atmospheres that are cool, but charged more than expected by pure thermal ionization.

  4. Laboratory Evaluation and Application of Microwave Absorption Properties Under Simulated Conditions for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1998-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments, entry probe radio signal absorption measurements, and earth-based radio astronomical observations can be used to infer abundances of microwave absorbing constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The use of theoretically-derived microwave absorption properties for such atmospheric constituents, or using laboratory measurements of such properties taken under environmental conditions which are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. For example, laboratory measurements completed recently by Kolodner and Steffes (ICARUS 132, pp. 151-169, March 1998, attached as Appendix A) under this grant (NAGS-4190), have shown that the opacity from gaseous H2SO4 under simulated Venus conditions is best described by a different formalism than was previously used. The recognition of the need to make such laboratory measurements of simulated planetary atmospheres over a range of temperatures and pressures which correspond to the altitudes probed by both spacecraft entry probe and orbiter radio occultation experiments and by radio astronomical observations, and over a range of frequencies which correspond to those used in such experiments, has led to the development of a facility at Georgia Tech which is capable of making such measurements. It has been the goal of this investigation to conduct such measurements and to apply the results to a wide range of planetary observations, both spacecraft and earth-based, in order to determine the identity and abundance profiles of constituents in those planetary atmospheres.

  5. Extrasolar Planets and the Power of the Dark Side

    SciTech Connect

    Charbonneau, David (California Institute of Technology) [California Institute of Technology

    2002-04-24

    It is only in the last decade that we have direct evidence for planets orbiting nearby Sun-like stars. If such planets happen to pass in front of their stars, we are presented with a golden opportunity to learn about the nature of these objects. Measurements of the dimming of starlight and gravitational wobble allow us to derive the planetary radius and mass, and, by inference, its composition. Recently, we used the Hubble Telescope to detect and study the atmosphere of an extrasolar planet for the first time. I will describe what we have learned about these planets

  6. Extrasolar Planets & The Power of the Dark Side

    SciTech Connect

    Dr. David Charbonneau

    2009-04-24

    It is only in the last decade that we have direct evidence for planets orbiting nearby Sun-like stars. If such planets happen to pass in front of their stars, we are presented with a golden opportunity to learn about the nature of these objects. Measurements of the dimming of starlight and gravitational wobble allow us to derive the planetary radius and mass, and, by inference, its composition. Recently, we used the Hubble Telescope to detect and study the atmosphere of an extrasolar planet for the first time. I will describe what we have learned about these planets 

  7. Large scale modulations of spectral aerosol optical depths by atmospheric planetary waves

    Microsoft Academic Search

    S. Naseema Beegum; K. Krishna Moorthy; S. Suresh Babu; R. Ramakrishna Reddy; K. Rama Gopal

    2009-01-01

    Analysis of 6 years of spectral aerosol optical depths (AOD), obtained during boreal winter at the tropical semi-arid location Anantapur, India, revealed significant modulations (to the seasonal mean AOD) by planetary scale atmospheric waves. Most significant contributions came from 30 to 50 day, and quasi-16 day periodicities; each contributing ?10% to 24%, and jointly up to 45% to the seasonal

  8. AIAA JOURNAL VOL. 1, NO. 1 Structure of Planetary Atmospheres

    E-print Network

    of the atmospheres of Venus and Jupiter. Recent measurements of the intensity of the radiation emitted by the planet of the planet. Also, there is evidence that the atmosphere of Venus may not be composed pre- dominantly of C02 reflected by the planet; total integratedalbedo corresponds to the albedo over the whole solar spectrum

  9. Possibility of growth of airborne microbes in outer planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Dimmick, R. L.; Chatigny, M. A.

    1975-01-01

    It is shown that airborne bacteria can maintain metabolic functions in a suitable atmosphere. It is theorized that particles in the Jovian atmosphere would have physical half-lives of 10 to 1500 years, depending upon which of two turbulent models is chosen.

  10. VUV photochemistry simulation of planetary upper atmosphere using synchrotron radiation.

    PubMed

    Carrasco, Nathalie; Giuliani, Alexandre; Correia, Jean Jacques; Cernogora, Guy

    2013-07-01

    The coupling of a gas reactor, named APSIS, with a vacuum-ultraviolet (VUV) beamline at the SOLEIL synchrotron radiation facility, for a photochemistry study of gas mixtures, is reported. The reactor may be irradiated windowless with gas pressures up to hundreds of millibar, and thus allows the effect of energetic photons below 100 nm wavelength to be studied on possibly dense media. This set-up is perfectly suited to atmospheric photochemistry investigations, as illustrated by a preliminary report of a simulation of the upper atmospheric photochemistry of Titan, the largest satellite of Saturn. Titan's atmosphere is mainly composed of molecular nitrogen and methane. Solar VUV irradiation with wavelengths no longer than 100 nm on the top of the atmosphere enables the dissociation and ionization of nitrogen, involving a nitrogen chemistry specific to nitrogen-rich upper atmospheres. PMID:23765300

  11. Microlensing Extrasolar Planets

    E-print Network

    Gaudi, B. Scott

    Microlensing Searches for Extrasolar Planets Microlensing Searches for Extrasolar Planets Microlensing Searches for Extrasolar Planets, B. Scott Gaudi, IAS Scientific Frontiers in Research on Extrasolar Planets, June 19, 2002 #12;Microlensing and PlanetsMicrolensing and Planets Microlensing Searches

  12. Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b

    SciTech Connect

    Barman, T S; Macintosh, B A; Konopacky, Q M; Marois, C

    2011-03-21

    Using the integral field spectrograph OSIRIS, on the Keck II telescope, broad near-infrared H and K-band spectra of the young exoplanet HR8799b have been obtained. In addition, six new narrow-band photometric measurements have been taken across the H and K bands. These data are combined with previously published photometry for an analysis of the planet's atmospheric properties. Thick photospheric dust cloud opacity is invoked to explain the planet's red near-IR colors and relatively smooth near-IR spectrum. Strong water absorption is detected, indicating a Hydrogen-rich atmosphere. Only weak CH{sub 4} absorption is detected at K band, indicating efficient vertical mixing and a disequilibrium CO/CH{sub 4} ratio at photospheric depths. The H-band spectrum has a distinct triangular shape consistent with low surface gravity. New giant planet atmosphere models are compared to these data with best fitting bulk parameters, T{sub eff} = 1100K {+-} 100 and log(g) = 3.5 {+-} 0.5 (for solar composition). Given the observed luminosity (log L{sub obs}/L{sub {circle_dot}} {approx} -5.1), these values correspond to a radius of 0.75 R{sub Jup{sub 0.12}{sup +0.17}} and mass {approx} 0.72 M{sub Jup{sub -0.6}{sup +2.6}} - strikingly inconsistent with interior/evolution models. Enhanced metallicity (up to {approx} 10 x that of the Sun) along with thick clouds and non-equilibrium chemistry are likely required to reproduce the complete ensemble of spectroscopic and photometric data and the low effective temperatures (< 1000K) required by the evolution models.

  13. The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs

    E-print Network

    Bailey, Jeremy

    2014-01-01

    The last few years has seen a dramatic increase in the number of exoplanets known and in the range of methods for characterising their atmospheric properties. At the same time, new discoveries of increasingly cooler brown dwarfs have pushed down their temperature range which now extends down to Y-dwarfs of planets there is good evidence for the presence of CO and H2O absorptions in the IR. Sodium absorption is observed in a number of objects. Reflected light measurements show that some giant exo...

  14. Aerobots and Hydrobots for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Barrett, Chris

    2000-01-01

    In this new Millennium, NASA will expand its presence in space. Many new planetary bodies have been discovered, and some previously known bodies are now believed to have oceans. We now know of 66 moons in our own Solar System, one with an atmosphere, 16 with water ice or oceans, and 5 with both. In addition, we now know of 20 extra-solar planets. In order to expand our presence in space and explore in a cost effective manner, we need a repertoire of new types of planetary exploration vehicles to explore both atmospheres and oceans. To address this need a spectrum of new classes of vehicles are being developed. These include aerobots and hydrobots, and incorporate Department of Defense miniaturization developments and smart materials. This paper outlines: the remarkable miniaturization developments applicable to robotic vehicles for the exploration of planetary atmospheres and oceans; Aerobots, the vehicles designed for planetary atmospheric exploration; Hydrobots, those designed for planetary ocean exploration; planetary atmospheric data; and Europa ocean exploration missions.

  15. Planetary host stars: evaluating uncertainties in cool model atmospheres

    NASA Astrophysics Data System (ADS)

    Bozhinova, I.; Helling, Ch.; Scholz, A.

    2015-06-01

    M-dwarfs are emerging in the literature as promising targets for detecting low-mass, Earth-like planets. An important step in this process is to determine the stellar parameters of the M-dwarf host star as accurately as possible. Different well-tested stellar model atmosphere simulations from different groups are widely applied to undertake this task. This paper provides a comparison of different model atmosphere families to allow a better estimate of systematic errors on host-star stellar parameter introduced by the use of one specific model atmosphere family only. We present a comparison of the ATLAS9, MARCS, PHOENIX and DRIFT-PHOENIX model atmosphere families including the M-dwarf parameter space (Teff = 2500-4000 K, log(g) = 3.0-5.0, [M/H] = -2.5to0.5). We examine the differences in the (Tgas, pgas)-structures, in synthetic photometric fluxes and in colour indices. Model atmospheres results for higher log(g) deviate considerably less between different models families than those for lower log(g) for all Teff = 2500-4000 K examined. We compiled the broad-band synthetic photometric fluxes for all available model atmospheres (incl. M-dwarfs and brown dwarfs) for the UKIRT WFCAM ZYJHK, 2MASS JHKs and Johnson UBVRI filters, and calculated related colour indices. Synthetic colours in the IR wavelengths diverge by no more than 0.15 dex amongst all model families. For all spectral bands considered, model discrepancies in colour diminish for higher Teff atmosphere simulations. We notice differences in synthetic colours between all model families and observed example data (including Kepler 42 and GJ1214).

  16. PLATO: PLAnetary Transits and Oscillations of stars

    NASA Astrophysics Data System (ADS)

    Rauer, Heike

    2013-04-01

    This decade is witnessing a rapid increase in our understanding of the nature of extra-solar planet systems and their host stars. Missions such as Corot and Kepler have confirmed that not only are extra-solar planets a common occurrence, but that multiple planetary systems are also the norm. Whilst there has been significant progress in discovery and to some extent understanding of extra solar planets and their host star(s), major questions remain as we seek to reveal the presence of extra-solar planets harbouring life. PLATO is a proposed ESA M3 mission which will revolutionise our understanding of extra-solar planets, through its discovery of planets around hundreds of thousands of stars, orders of magnitudes more than previously known. Its exquisite sensitivity will ensure that it detects planets to Earth masses and within the 'habitable' zone. PLATO will probe the interiors of both the host star(s) and their orbiting planetary systems. This presentation will describe the PLATO science yield: detecting Earth-sized planets in the habitable zone with known radii and masses, including planets orbiting solar-like stars; obtaining statistically significant numbers of characterized small planets at different orbits, around various star types; thus providing a set of well characterised small terrestrial planets around bright stars as constraints to planet formation theories and as targets for future atmosphere spectroscopy.

  17. Wide-Band Heterodyne Submillimetre Wave Spectrometer for Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Schlecht, Erich

    2010-01-01

    We present calculations and measurements on a passive submillimetre wave spectroscopic sounder to gather data on the thermal structure, dynamics and composition of the upper atmosphere of a planet, e.g. the stratosphere of Jupiter, or the entire thickness of the atmosphere of Mars. The instrument will be capable of measuring wind speeds, temperature, pressure, and key constituent concentrations in the stratosphere of the target planet. This instrument consists of a Schottky diode based front end and a digital back-end spectrometer. It differs from previous space-based spectrometers in its combination of wide tunability (520-590 GHz), and rapid frequency switching between widely spaced lines within that range. This will enable near simultaneous observation of multiple lines, which is critical to the reconstruction of atmospheric pressure and density versus altitude profiles. At the same time frequency accuracy must be high to enable wind speeds to be determined directly by measurement of the line's Doppler shift.

  18. 3.6 AND 4.5 {mu}m PHASE CURVES AND EVIDENCE FOR NON-EQUILIBRIUM CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HD 189733b

    SciTech Connect

    Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Lewis, Nikole; Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Fortney, Jonathan J.; Laughlin, Gregory [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Cowan, Nicolas B. [CIERA, Northwestern University, Evanston, IL 60208 (United States); Agol, Eric [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Aigrain, Suzanne [Sub-department of Astrophysics, Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom); Charbonneau, David; Desert, Jean-Michel [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Langton, Jonathan, E-mail: hknutson@caltech.edu [Department of Physics, Principia College, 1 Maybeck Place, Elsah, IL 62028 (United States)

    2012-07-20

    We present new, full-orbit observations of the infrared phase variations of the canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 {mu}m bands using the Spitzer Space Telescope. When combined with previous phase curve observations at 8.0 and 24 {mu}m, these data allow us to characterize the exoplanet's emission spectrum as a function of planetary longitude and to search for local variations in its vertical thermal profile and atmospheric composition. We utilize an improved method for removing the effects of intrapixel sensitivity variations and robustly extracting phase curve signals from these data, and we calculate our best-fit parameters and uncertainties using a wavelet-based Markov Chain Monte Carlo analysis that accounts for the presence of time-correlated noise in our data. We measure a phase curve amplitude of 0.1242% {+-} 0.0061% in the 3.6 {mu}m band and 0.0982% {+-} 0.0089% in the 4.5 {mu}m band, corresponding to brightness temperature contrasts of 503 {+-} 21 K and 264 {+-} 24 K, respectively. We find that the times of minimum and maximum flux occur several hours earlier than predicted for an atmosphere in radiative equilibrium, consistent with the eastward advection of gas by an equatorial super-rotating jet. The locations of the flux minima in our new data differ from our previous observations at 8 {mu}m, and we present new evidence indicating that the flux minimum observed in the 8 {mu}m is likely caused by an overshooting effect in the 8 {mu}m array. We obtain improved estimates for HD 189733b's dayside planet-star flux ratio of 0.1466% {+-} 0.0040% in the 3.6 {mu}m band and 0.1787% {+-} 0.0038% in the 4.5 {mu}m band, corresponding to brightness temperatures of 1328 {+-} 11 K and 1192 {+-} 9 K, respectively; these are the most accurate secondary eclipse depths obtained to date for an extrasolar planet. We compare our new dayside and nightside spectra for HD 189733b to the predictions of one-dimensional radiative transfer models from Burrows et al. and conclude that fits to this planet's dayside spectrum provide a reasonably accurate estimate of the amount of energy transported to the night side. Our 3.6 and 4.5 {mu}m phase curves are generally in good agreement with the predictions of general circulation models for this planet from Showman et al., although we require either excess drag or slower rotation rates in order to match the locations of the measured maxima and minima in the 4.5, 8.0, and 24 {mu}m bands. We find that HD 189733b's 4.5 {mu}m nightside flux is 3.3{sigma} smaller than predicted by these models, which assume that the chemistry is in local thermal equilibrium. We conclude that this discrepancy is best explained by vertical mixing, which should lead to an excess of CO and correspondingly enhanced 4.5 {mu}m absorption in this region. This result is consistent with our constraints on the planet's transmission spectrum, which also suggest excess absorption in the 4.5 {mu}m band at the day-night terminator.

  19. Atmospheric tides on Venus. III - The planetary boundary layer

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, A. R.

    1983-10-01

    Diurnal solar heating of Venus' surface produces variable temperatures, winds, and pressure gradients within a shallow layer at the bottom of the atmosphere. The corresponding asymmetric mass distribution experiences a tidal torque tending to maintain Venus' slow retrograde rotation. It is shown that including viscosity in the boundary layer does not materially affect the balance of torques. On the other hand, friction between the air and ground can reduce the predicted wind speeds from about 5 to about 1 m/sec in the lower atmosphere, more consistent with the observations from Venus landers and descent probes. Implications for aeolian activity on Venus' surface and for future missions are discussed.

  20. Mechanisms and observations for isotope fractionation of molecular species in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Kaye, Jack A.

    1987-01-01

    Chemcial and physical processes which may give rise to isotope fractionation of molecular species in the atmospheres of both earth and other planets are reviewed, along with observations of isotopically substituted molecules in planetary atmospheres. Mechanisms for production of isotope fractionation considered include atmospheric escape and the effect of isotope substitution on equilibrium constants (including those of phase changes), photolysis rates, and chemical reaction rates. The isotopes considered for compounds in the terrestrial atmosphere include D, T, C-13, C-14, N-15, O-18, and S-34. Compounds for which data about isotopic composition in the terrestrial atmosphere are summarized include CO, CO2, O3, N2O, NH3, SO2, H2S, H2O, H, H2, and CH4. Planetary atmospheres discussed include those of Venus, Mars, Jupiter, Saturn, Uranus, and Titan; isotopes reviewed are D, C-13, N-15, and O-18. Suggestions for additional research in the area of isotopically substituted molecules in atmospheres are offered.

  1. Seeing the Invisible: Educating the Public on Planetary Magnetic Fields and How they Affect Atmospheres

    NASA Astrophysics Data System (ADS)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Schultz, G.; Yan, D.; Guevara, S.; Randol, S.

    2009-12-01

    Magnetic fields and charged particles are difficult for school children, the general public, and scientists alike to visualize. But studies of planetary magnetospheres and ionospheres have broad implications for planetary evolution, from the deep interior to the ancient climate, that are important to communicate to each of these audiences. This presentation will highlight the visualization materials that we are developing to educate audiences on the magnetic fields of planets and how they affect atmospheres. The visualization materials that we are developing consist of simplified data sets that can be displayed on spherical projection systems and portable 3-D rigid models of planetary magnetic fields.We are developing presentations for science museums and classrooms that relate fundamental information about the Martian magnetic field, how it differs from Earth’s, and why the differences are significant.

  2. Volatile inventory and early evolution of the planetary atmospheres

    Microsoft Academic Search

    Mikhail Ya. Marov; Sergei I. Ipatov

    2001-01-01

    Formation of atmospheres of the inner planets involved the concurrent processes of mantle degassing and collisions that culminated during the heavy bombardment. Volatile-rich icy planetesimals impacting on the planets as a late veneer strongly contributed to the volatile inventory. Icy remnants of the outer planet accretion significantly complemented the accumulation of the lithophile and atmophile elements forced out onto the

  3. Observations of Extrasolar Planet Transits: What's next?

    NASA Astrophysics Data System (ADS)

    Rauer, H.

    2014-03-01

    Transits of extrasolar planets are a goldmine for our understanding of the physical nature of planets beyond the Solar System. Measurements of radii from transit observations combined with mass determinations from radial velocity spectroscopy, or transit timing variations, have provided the first indications to the planetary composition and interior structure. It turns out that planets show a much richer diversity than found in our own planetary system, considering e.g. the so-called 'super-Earths', 'mini-Neptunes', and inflated giant planets. Transiting exoplanets also allow for spectroscopic observations of their atmospheres, either during transit or near secondary eclipse. Exoplanets showing transits have therefore been identified as key observables, not only for planet detection, but in particular for investigating further planetary nature. As a result, a new generation of instruments (space- and groundbased) for exoplanet transit observations is already in the construction phase and is planned for the near future. Most of these target specifically stars bright enough for spectroscopic follow-up observations, a èlesson learned' from past transit surveys. A clear goal for future investigations of habitable planets is the detection and characterization of terrestrial planets which potentially could harbor life. This talk will review the status and in particular the future of transit observations, with a focus on rocky planets in the habitable zone of their host stars.

  4. Can We Probe the Atmospheric Composition of an Extrasolar Planet from its Reflection Spectrum in a High-Magnification Microlensing Event?

    E-print Network

    David S. Spiegel; Michel Zamojski; Alan Gersch; Jennifer Donovan; Zoltan Haiman

    2005-06-17

    We revisit the possibility of detecting an extrasolar planet around a background star as it crosses the fold caustic of a foreground binary lens. During such an event, the planet's flux can be magnified by a factor of ~100 or more. The detectability of the planet depends strongly on the orientation of its orbit relative to the caustic. If the source star is inside the inter-caustic region, detecting the caustic-crossing planet is difficult against the magnified flux of its parent star. In the more favorable configuration, when the star is outside the inter-caustic region when the planet crosses the caustic, a close-in Jupiter-like planet around a Sun-like star at a distance of 8 kpc is detectable in 8-minute integrations with a 10m telescope at maximal S/N~15 for phase angle ~10 degrees. In this example, we find further that the presence of methane, at its measured abundance in Jupiter, and/or water, sodium and potassium, at the abundances expected in theoretical atmosphere models of close-in Jupiters, could be inferred from a non-detection of the planet in strong broad absorption bands at 0.6-1.4 microns caused by these compounds, accompanied by a S/N~10 detection in adjacent bands. We conclude that future generations of large telescopes might be able to probe the composition of the atmospheres of distant extrasolar planets.

  5. On the temperature distribution in a planetary atmosphere.

    NASA Technical Reports Server (NTRS)

    Young, L. D. G.; Young, A. T.

    1972-01-01

    Criteria for the appearance of a double maximum in the absorption spectra are derived. A very oversimplified model atmosphere which consists of two isothermal layers of gas is considered. The model involves the presence of two absorption cells in series, in front of a light source that has a higher temperature than either of the cells. The possibility that the double maximum is due to a quantum-mechanical interaction is studied. It is concluded that the effect reported by Kaplan (1962) was due to noise, and that it is impossible to detect temperatures as high as 700 K in the atmosphere of Venus by means of ground-based observations of the 7820 A carbon dioxide band.

  6. Acoustic measurements of atmospheric electrical discharges for planetary probes

    NASA Astrophysics Data System (ADS)

    Eichelberger, H.; Prattes, G.; Schwingenschuh, K.; Jaffer, G.; Aydogar, Ö.; Jernej, I.; Besser, B.; Stachel, M.; Tokano, T.; Falkner, P.

    2010-05-01

    We present acoustic measurements carried out in a high voltage laboratory in order to characterise signals from various discharge processes, e.g. lightning or corona discharge. The investigations are in the frame of the Acoustic Sensor Package (ACU) for Titan Saturn System Mission (TSSM), a proposed post Cassini-Huygens mission. The multi-microphone system ACU has the scientific objective to characterise acoustical phenomena in Titan's atmosphere with heritage from Huygens Atmospheric Structure Instrument (HASI/PWA) on Huygens probe. We investigate the possibility to use acoustic measurements for the study of atmospheric electrical discharges. The experiments in the high voltage lab used a generator with voltages up to 1.9 million volts with different polarities. Various discharges have been generated and acoustical signals detected. From the sound signature we derive parameters which influence the technical design of ACU, e.g. filter coefficients for capturing fast transient acoustic phenomena and intermittent signals. In addition multi-microphone sound systems can be used to estimate the location of discharges.

  7. PHYSICS OF PLANETS: OBSERVING EXTRASOLAR GIANT PLANETS WITH Tristan Guillot

    E-print Network

    Guillot, Tristan

    1 PHYSICS OF PLANETS: OBSERVING EXTRASOLAR GIANT PLANETS WITH DARWIN/TPF Tristan Guillot/TPF. Extrasolar giant planets are milestones on the quest for our origins: they hold crucial information con for those objects with little or no atmosphere). On the other hand, extrasolar giant planets represent a new

  8. Decadal regime shift linkage between global marine fish landings and atmospheric planetary wave forcing

    NASA Astrophysics Data System (ADS)

    Powell, A. M., Jr.; Xu, J.

    2014-08-01

    This investigation focuses on a global forcing mechanism for decadal regime shifts and their subsequent impacts. The proposed global forcing mechanism is the global atmospheric planetary waves that can lead to changes in the global surface air-sea conditions and subsequently fishery changes. In this study, the five decadal regime shifts (1956-1957, 1964-1965, 1977-1978, 1988-1989, and 1998-1999) in the recent 59 years (1950-2008) have been identified based on student t tests and their association with global marine ecosystem change has been discussed. Changes in the three major oceanic (Pacific, Atlantic and Indian) ecosystems will be explored with the goal of demonstrating the linkage between stratospheric planetary waves and the ocean surface forcing that leads to fisheries impacts. Due to the multidisciplinary audience, the global forcing mechanism is described from a top-down approach to help the multidisciplinary audience follow the analysis. Following previous work, this analysis addresses how changes in the atmospheric planetary waves may influence the vertical wind structure, surface wind stress, and their connection with the global ocean ecosystems based on a coupling of the atmospheric regime shifts with the decadal regime shifts determined from marine life changes. The multiple decadal regime shifts related to changes in marine life are discussed using the United Nations Food and Agriculture Organization's (FAO) global fish capture data (catch/stock). Analyses are performed to demonstrate the interactions between the atmosphere, ocean, and fisheries are a plausible approach to explaining decadal climate change in the global marine ecosystems and its impacts. The results show a consistent mechanism, ocean wind stress, responsible for marine shifts in the three major ocean basins. Changes in the planetary wave pattern affect the ocean wind stress patterns. A change in the ocean surface wind pattern from long wave (relatively smooth and less complex) to shorter wave (more convoluted and more complex) ocean surface wind stress creates changes in the ocean marine fisheries.

  9. When Extrasolar Planets Transit Their Parent Stars

    E-print Network

    David Charbonneau; Timothy M. Brown; Adam Burrows; Greg Laughlin

    2006-03-14

    When extrasolar planets are observed to transit their parent stars, we are granted unprecedented access to their physical properties. It is only for transiting planets that we are permitted direct estimates of the planetary masses and radii, which provide the fundamental constraints on models of their physical structure. In particular, precise determination of the radius may indicate the presence (or absence) of a core of solid material, which in turn would speak to the canonical formation model of gas accretion onto a core of ice and rock embedded in a protoplanetary disk. Furthermore, the radii of planets in close proximity to their stars are affected by tidal effects and the intense stellar radiation. As a result, some of these "hot Jupiters" are significantly larger than Jupiter in radius. Precision follow-up studies of such objects (notably with the space-based platforms of the Hubble and Spitzer Space Telescopes) have enabled direct observation of their transmission spectra and emitted radiation. These data provide the first observational constraints on atmospheric models of these extrasolar gas giants, and permit a direct comparison with the gas giants of the Solar system. Despite significant observational challenges, numerous transit surveys and quick-look radial velocity surveys are active, and promise to deliver an ever-increasing number of these precious objects. The detection of transits of short-period Neptune-sized objects, whose existence was recently uncovered by the radial-velocity surveys, is eagerly anticipated. Ultra-precise photometry enabled by upcoming space missions offers the prospect of the first detection of an extrasolar Earth-like planet in the habitable zone of its parent star, just in time for Protostars and Planets VI.

  10. Spectrophotometry of planetary atmosphere from the X-15 rocket airplane

    NASA Technical Reports Server (NTRS)

    Murcray, W. B.

    1973-01-01

    Nike-Apache and Nike-Tomahawk rocket flights using spectrophotometric techniques to investigate auroral activity are reported. The specific objectives were to obtain data relative to typical auroral situations, including quiet pre-breakup auroras, westward traveling surges, breakup auroras, and post-breakup auroras. It was found that excited atoms move considerable distances between excitation and emission owing to the high velocity wind conditions prevailing above 200 km. Based on the results of these observations, recommendations are made for future studies of ionized atmospheric activity at higher altitudes.

  11. Spectropolarimetric signatures of Earth-like extrasolar planets

    E-print Network

    D. M. Stam

    2007-07-26

    We present results of numerical simulations of the flux (irradiance), F, and the degree of polarization (i.e. the ratio of polarized to total flux), P, of light that is reflected by Earth-like extrasolar planets orbiting solar-type stars, as functions of the wavelength (from 0.3 to 1.0 micron, with 0.001 micron spectral resolution) and as functions of the planetary phase angle. We use different surface coverages for our model planets, including vegetation and a Fresnel reflecting ocean, and clear and cloudy atmospheres. Our adding-doubling radiative transfer algorithm, which fully includes multiple scattering and polarization, handles horizontally homogeneous planets only; we simulate fluxes and polarization of horizontally inhomogeneous planets by weighting results for homogeneous planets. Like the flux, F, the degree of polarization, P, of the reflected starlight is shown to depend strongly on the phase angle, on the composition and structure of the planetary atmosphere, on the reflective properties of the underlying surface, and on the wavelength, in particular in wavelength regions with gaseous absorption bands. The sensitivity of P to a planet's physical properties appears to be different than that of F. Combining flux with polarization observations thus makes for a strong tool for characterizing extrasolar planets. The calculated total and polarized fluxes will be made available through the CDS.

  12. ON THE PERIOD DISTRIBUTION OF CLOSE-IN EXTRASOLAR GIANT PLANETS B. Scott Gaudi,1

    E-print Network

    Gaudi, B. Scott

    ON THE PERIOD DISTRIBUTION OF CLOSE-IN EXTRASOLAR GIANT PLANETS B. Scott Gaudi,1 S. Seager,2) surveys for extrasolar planets have recently uncovered a population of ``very hot Jupiters,'' planets properties of extrasolar planets. This information, in turn, provides clues to the nature of planetary

  13. How do Atmospheres Affect Planetary Temperatures? Activity B How do Atmospheres Produce their Effect Upon Surface Temperatures?

    NSDL National Science Digital Library

    2012-08-03

    In this kinesthetic activity, the concept of energy budget is strengthened as students conduct three simulations using play money as units of energy, and students serve as parts of a planetary radiation balance model. Students will determine the energy budget of a planet by manipulating gas concentrations, energy inputs and outputs in the system in this lesson that supports the study of climate on Mars, Mercury, Venus and Earth. The lesson supports understanding of the real-world problem of contemporary climate change. The resource includes a teacher's guide and several student worksheets. This is the second of four activities in the lesson, How do Atmospheres affect planetary temperatures?, within Earth Climate Course: What Determines a Planet's Climate? The resource aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

  14. Grain opacity and the bulk composition of extrasolar planets. II. An analytical model for the grain opacity in protoplanetary atmospheres

    E-print Network

    Mordasini, C

    2014-01-01

    Context. We investigate the grain opacity k_gr in the atmosphere of protoplanets. This is important for the planetary mass-radius relation since k_gr affects the H/He envelope mass of low-mass planets and the critical core mass of giant planets. Aims. The goal of this study is to derive an analytical model for k_gr. Methods. Our model is based on the comparison of the timescales of microphysical processes like grain settling in the Stokes and Epstein regime, growth by Brownian motion coagulation and differential settling, grain evaporation, and grain advection due to envelope contraction. With these timescales we derive the grain size, abundance, and opacity. Results. We find that the main growth process is differential settling. In this regime, k_gr has a simple functional form and is given as 27 Q/8 H rho in the Epstein regime and as 2 Q/H rho for Stokes drag. Grain dynamics lead to a typical radial structure of k_gr with high ISM-like values in the top layers but a strong decrease in the deeper parts where...

  15. Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

    NASA Astrophysics Data System (ADS)

    Lammer, Helmut; Güdel, Manuel; Kulikov, Yuri; Ribas, Ignasi; Zaqarashvili, Teimuraz V.; Khodachenko, Maxim L.; Kislyakova, Kristina G.; Gröller, Hannes; Odert, Petra; Leitzinger, Martin; Fichtinger, Bibiana; Krauss, Sandro; Hausleitner, Walter; Holmström, Mats; Sanz-Forcada, Jorge; Lichtenegger, Herbert I. M.; Hanslmeier, Arnold; Shematovich, Valery I.; Bisikalo, Dmitry; Rauer, Heike; Fridlund, Malcolm

    2012-02-01

    It is shown that the evolution of planetary atmospheres can only be understood if one recognizes the fact that the radiation and particle environment of the Sun or a planet's host star were not always on the same level as at present. New insights and the latest observations and research regarding the evolution of the solar radiation, plasma environment and solar/stellar magnetic field derived from the observations of solar proxies with different ages will be given. We show that the extreme radiation and plasma environments of the young Sun/stars have important implications for the evolution of planetary atmospheres and may be responsible for the fact that planets with low gravity like early Mars most likely never build up a dense atmosphere during the first few 100 Myr after their origin. Finally we present an innovative new idea on how hydrogen clouds and energetic neutral atom (ENA) observations around transiting Earth-like exoplanets by space observatories such as the WSO-UV, can be used for validating the addressed atmospheric evolution studies. Such observations would enhance our understanding on the impact on the activity of the young Sun on the early atmospheres of Venus, Earth, Mars and other Solar System bodies as well as exoplanets.

  16. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1988-01-01

    Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The key activity for this grant year has continued to be laboratory measurements of the microwave and millimeter-wave properties of the simulated atmospheres of the outer planets and their satellites. A Fabry-Perot spectrometer system capable of operation from 32 to 41 GHz was developed. Initially this spectrometer was used to complete laboratory measurements of the 7.5 to 9.3 mm absorption spectrum of ammonia. Laboratory measurements were begun at wavelengths near 3.2 mm, where a large number of observations of the emission from the outer planets were made. A description of this system is presented.

  17. Superrotation planetary atmospheres: Mechanical analogy, angular momentum budget and simulation of the spin up process

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Harris, I.; Conrath, B. J.

    1981-01-01

    Superrotation rates observed in planetary atmospheres are analyzed based on the concept of a thermally driven zonally symmetric circulation. Specifically, how this superrotation is produced and maintained against the tendency for friction to oppose differential motions between the atmosphere and the underlying planet is addressed. The time evolution of a fluid leading from corotation under uniform heating to superrotation under globally nonuniform heating is simulated using a three dimensional zonally symmetric spectral model and Laplace transformation. The increased tendency toward geostrophy combined with the increase of surface pressure toward the poles (due to meridional mass transport), induces the atmosphere to subrotate temporarily at lower altitudes. The resulting viscous shear near the surface thus permits angular momentum to flow from the planet into the atmosphere where it propagates upwards and, combined with the change in moment of inertia, produces large superrotation rates at higher viscosities.

  18. Detecting tree-like multicellular life on extrasolar planets.

    PubMed

    Doughty, Christopher E; Wolf, Adam

    2010-11-01

    Over the next two decades, NASA and ESA are planning a series of space-based observatories to find Earth-like planets and determine whether life exists on these planets. Previous studies have assessed the likelihood of detecting life through signs of biogenic gases in the atmosphere or a red edge. Biogenic gases and the red edge could be signs of either single-celled or multicellular life. In this study, we propose a technique with which to determine whether tree-like multicellular life exists on extrasolar planets. For multicellular photosynthetic organisms on Earth, competition for light and the need to transport water and nutrients has led to a tree-like body plan characterized by hierarchical branching networks. This design results in a distinct bidirectional reflectance distribution function (BRDF) that causes differing reflectance at different sun/view geometries. BRDF arises from the changing visibility of the shadows cast by objects, and the presence of tree-like structures is clearly distinguishable from flat ground with the same reflectance spectrum. We examined whether the BRDF could detect the existence of tree-like structures on an extrasolar planet by using changes in planetary albedo as a planet orbits its star. We used a semi-empirical BRDF model to simulate vegetation reflectance at different planetary phase angles and both simulated and real cloud cover to calculate disk and rotation-averaged planetary albedo for a vegetated and non-vegetated planet with abundant liquid water. We found that even if the entire planetary albedo were rendered to a single pixel, the rate of increase of albedo as a planet approaches full illumination would be comparatively greater on a vegetated planet than on a non-vegetated planet. Depending on how accurately planetary cloud cover can be resolved and the capabilities of the coronagraph to resolve exoplanets, this technique could theoretically detect tree-like multicellular life on exoplanets in 50 stellar systems. PMID:21118020

  19. Extrasolar Planetary Imaging Coronagraph (EPIC)

    NASA Technical Reports Server (NTRS)

    Clampin, Mark

    2009-01-01

    EPIC is a NASA mission being studied to detect and characterize Jovian and superEarth planets, and, the dust/debris disks surrounding the parent star. It will be launched into a heliocentric Earth trailing orbit and operate for 5 years. EPIC would operate over the wavelength range of 480 - 960 nm with spectral resolutions of R < 50 and employs a visible nulling coronagraph (VNC) to suppress the starlight, yielding contrast ratios of greater than 9 orders of magnitude. We will discuss the science mission, and its role in the search for habitable planets.

  20. Microlensing search for extrasolar planets

    E-print Network

    A. Cassan; D. Kubas

    2006-12-01

    Microlensing has recently proven to be a valuable tool to search for extrasolar planets of Neptune- to super-Earth-mass planets at orbits of few AU. Since planetary signals are of very short duration, an intense and continuous monitoring is required, which is achieved by PLANET : ``Probing Lensing Anomalies NETwork''. Up to now the detection number amounts to four, one of them being OGLE 2005-BLG-390Lb, an extrasolar planet of only ~5.5 M_earth orbiting its M-dwarf host star at ~2.6 AU. For non-planetary microlensing events observed from 1995 to 2006, we compute detection efficiency diagrams which can then be used to derive an estimate of the limit on the Galactic abundance of sub-Jupiter-mass planets, as well as relative abundance of Neptune-like planets.

  1. Kinetics of Suprathermal Atoms and Molecules in the Rarefied Planetary Atmospheres

    SciTech Connect

    Shematovich, Valery I. [Institute of Astronomy of the Russian Academy of Sciences, 48 Pyatnitskaya str., Moscow 119017 (Russian Federation)

    2008-12-31

    Ground-based and space observations have revealed that the upper layers of planetary atmospheres contain both a thermal fraction of neutral atoms and molecules with the mean particle kinetic energy corresponding to the local gas temperature and a suprathermal (hot) fraction of neutral particles with the mean kinetic energy much higher than the local atmospheric temperature. Atmospheric photochemistry and solar wind/magnetospheric plasma inflow play an important role in the formation of suprathermal atoms and molecules in the rarefied atmospheric gas. The current physical and mathematical models of suprathermal atom formation are presented. These models are used to investigate the formation and kinetics of suprathermal carbon, nitrogen, and oxygen atoms in the upper atmospheres of Venus, Earth, and Mars where they are formed in significant amounts due to the atmospheric photochemistry. The role and input of such photochemical reactions as photo- and electron impact dissociation of the main atmospheric constituents as well as in the exothermic ion-molecular reactions including the dissociative recombination of the ionospheric ions into the formation of hot O populations in the upper atmospheres of the terrestrial planets are estimated.

  2. Extrasolar planets

    Microsoft Academic Search

    M. A. C. Perryman

    2000-01-01

    The discovery of the first extra-solar planet surrounding a main-sequence star was announced in 1995, based on very precise radial velocity (Doppler) measurements. A total of 34 such planets were known by the end of March 2000, and their numbers are growing steadily. The newly discovered systems confirm some of the features predicted by standard theories of star and planet

  3. Planetary atmosphere models: A research and instructional web-based resource

    NASA Astrophysics Data System (ADS)

    Gray, Samuel Augustine

    The effects of altitude change on the temperature, pressure, density, and speed of sound were investigated. These effects have been documented in Global Reference Atmospheric Models (GRAMs) to be used in calculating the conditions in various parts of the atmosphere for several planets. Besides GRAMs, there are several websites that provide online calculators for the 1976 US Standard Atmosphere. This thesis presents the creation of an online calculator of the atmospheres of Earth, Mars, Venus, Titan, and Neptune. The websites consist of input forms for altitude and temperature adjustment followed by a results table for the calculated data. The first phase involved creating a spreadsheet reference based on the 1976 US Standard Atmosphere and other planetary GRAMs available. Microsoft Excel was used to input the equations and make a graphical representation of the temperature, pressure, density, and speed of sound change as altitude changed using equations obtained from the GRAMs. These spreadsheets were used later as a reference for the JavaScript code in both the design and comparison of the data output of the calculators. The websites were created using HTML, CSS, and JavaScript coding languages. The calculators could accurately display the temperature, pressure, density, and speed of sound of these planets from surface values to various stages within the atmosphere. These websites provide a resource for students involved in projects and classes that require knowledge of these changes in these atmospheres. This project also created a chance for new project topics to arise for future students involved in aeronautics and astronautics.

  4. On the role of electron-driven processes in planetary atmospheres and comets

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Brunger, M. J.

    2009-11-01

    After the presence of ionized layers in the Earth's atmosphere was inferred, it took 50 years to quantitatively understand them. The electron density could not be accounted for until Sir David Bates first suggested (along with Sir Harrie Massey) that the main electron-loss process was dissociative recombination with molecular ions, and he and colleagues then developed a theory to predict those rates of dissociative recombination. However, electron impact processes, particularly excitation, have been considered insignificant in most situations, in both planetary and cometary atmospheres. Here we describe cases where recent calculations have shown that electron impact excitation of molecules is important, suggesting that, just as in the time of Sir David Bates, electron-driven processes remain fundamental to our quantitative understanding of atmospheric and cometary phenomena.

  5. Ultra-High Resolution Spectroscopic Remote Sensing: A Microscope on Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodor

    2010-01-01

    Remote sensing of planetary atmospheres is not complete without studies of all levels of the atmosphere, including the dense cloudy- and haze filled troposphere, relatively clear and important stratosphere and the upper atmosphere, which are the first levels to experience the effects of solar radiation. High-resolution spectroscopy can provide valuable information on these regions of the atmosphere. Ultra-high spectral resolution studies can directly measure atmospheric winds, composition, temperature and non-thermal phenomena, which describe the physics and chemistry of the atmosphere. Spectroscopy in the middle to long infrared wavelengths can also probe levels where dust of haze limit measurements at shorter wavelength or can provide ambiguous results on atmospheric species abundances or winds. A spectroscopic technique in the middle infrared wavelengths analogous to a radio receiver. infrared heterodyne spectroscopy [1], will be describe and used to illustrate the detailed study of atmospheric phenomena not readily possible with other methods. The heterodyne spectral resolution with resolving power greater than 1,000.000 measures the true line shapes of emission and absorption lines in planetary atmospheres. The information on the region of line formation is contained in the line shapes. The absolute frequency of the lines can be measured to I part in 100 ,000,000 and can be used to accurately measure the Doppler frequency shift of the lines, directly measuring the line-of-sight velocity of the gas to --Im/s precision (winds). The technical and analytical methods developed and used to measure and analyze infrared heterodyne measurements will be described. Examples of studies on Titan, Venus, Mars, Earth, and Jupiter will be presented. 'These include atmospheric dynamics on slowly rotating bodies (Titan [2] and Venus [3] and temperature, composition and chemistry on Mars 141, Venus and Earth. The discovery and studies of unique atmospheric phenomena will also be described, such as non-thermal and lasing phenomena on Mars and Venus, mid-infrared aurora on Jupiter [5], and results of small body impacts on Jupiter [6]. The heterodyne technique can also be applied for detailed study of the Earth's stratosphere and mesosphere by measuring trace constituent abundances and temporal and spatial variability as well as winds, which provide information of transport. All ground-based measurements will be described as complementary and supporting studies for on-going and future space missions [7] (Mars Express, Venus Express, Cassini Huygens, JUNO, ExoMars Trace Gas Orbiter, and the Europa Jupiter System Mission, an Earth Science Venture Class missions), Proposed instrument and technology development for a space flight infrared heterodyne spectrometer will be described.

  6. GRAVITY WAVES ON HOT EXTRASOLAR PLANETS. I. PROPAGATION AND INTERACTION WITH THE BACKGROUND

    SciTech Connect

    Watkins, Chris [Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Cho, J. Y-K., E-mail: c.watkins@qmul.ac.u, E-mail: J.Cho@qmul.ac.u [Visiting Scientist, Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015 (United States)

    2010-05-01

    We study the effects of gravity waves, or g-modes, on hot extrasolar planets. These planets are expected to possess stably stratified atmospheres, which support gravity waves. In this paper, we review the derivation of the equation that governs the linear dynamics of gravity waves and describe its application to a hot extrasolar planet, using HD 209458 b as a generic example. We find that gravity waves can exhibit a wide range of behaviors, even for a single atmospheric profile. The waves can significantly accelerate or decelerate the background mean flow, depending on the difference between the wave phase and mean flow speeds. In addition, the waves can provide significant heating ({approx}10{sup 2} to {approx}10{sup 3} K per planetary rotation), especially to the region of the atmosphere above about 10 scale heights from the excitation region. Furthermore, by propagating horizontally, gravity waves provide a mechanism for transporting momentum and heat from the dayside of a tidally locked planet to its nightside. We discuss work that needs to be undertaken to incorporate these effects in current atmosphere models of extrasolar planets.

  7. Application of the Stogryn-Hirschfelder treatment of weak dimers to planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Slanina, Zdenek; Fox, Kenneth; Kim, Sang J.

    1992-01-01

    The thermodynamics of carbon dioxide dimerization is treated as an example of the evaluation of weak dimer populations in planetary atmospheres (e.g., Mars and Venus). Two approaches considered are the Stogryn-Hirschfelder (1960) treatment using the Lennard-Jones interaction and calculations based on recent quantum chemical data. Several improvements of these treatments are developed. It is indicated that carbon dioxide dimers may be less or more abundant at the surfaces of Mars or Venus, respectively, than is suggested by previous calculations.

  8. Small mass spectrometer with extended measurement capabilities at high pressures. [for planetary atmosphere analysis

    NASA Technical Reports Server (NTRS)

    Von Zahn, U.; Mauersberger, K.

    1978-01-01

    For the in situ investigation of planetary atmospheres a small Mattauch-Herzog mass spectrometer has been developed. Its high-pressure performance has been improved by incorporating differential pumping between the ion source and the analyzing fields, shortening the path-length as well as increasing the extraction field in the ion source. In addition doubly ionized and dissociated ions are used for mass analysis. These measures make possible operation up to 0.01 millibars. Results of laboratory tests related to linearity, dynamic range, and mass resolution are presented, in particular for CO2.

  9. Radio scintillations during occultations by turbulent planetary atmospheres. [remote sensing via flyby spacecraft

    NASA Technical Reports Server (NTRS)

    Woo, R.; Ishimaru, A.; Yang, F.-C.

    1980-01-01

    The radio occultation experiment which uses the radio link between the earth and spacecraft passing behind planets has proven to be an important method for remote sensing turbulence in planetary atmospheres. The effects of defocusing and anisotropic irregularities on the turbulence-induced fluctuations of the radio occultation signal are examined. Rytov's method along with geometrical optics is employed to study the frequency spectra and coherences of the log amplitude and phase fluctuations of spherical waves operating at one as well as two frequencies. Comparison with the Mariner 5 2.3-GHz measurements shows good agreement with the theoretical results.

  10. Planetary atmosphere evolution: do other habitable planets exist and can we detect them?

    PubMed

    Kasting, J F

    1996-01-01

    The goal of this conference is to consider whether it is possible within the next few decades to detect Earth-like planets around other stars using telescopes or interferometers on the ground or in space. Implicit in the term "Earth-like" is the idea that such planets might be habitable by Earth-like organisms, or that they might actually be inhabited. Here, I shall address two questions from the standpoint of planetary atmosphere evolution. First, what are the chances that habitable planets exist around other stars? And, second, if inhabited planets exist, what would be the best way to detect them? PMID:11542303

  11. 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

  12. Sloping convection: A paradigm for large-scale waves and eddies in planetary atmospheres?

    PubMed

    Hide, Raymond; Lewis, Stephen R.; Read, Peter L.

    1994-06-01

    In laboratory studies and associated theoretical and numerical work covering a very wide range of conditions (as specified by the key dimensionless parameters of the systems used) the phenomenon of sloping convection in rotating fluids can manifest itself in one of several spatial forms (waves, closed eddies, and combinations thereof), but all with strong local gradients (fronts, jet streams) and exhibiting various types of temporal behavior [steady, periodic vacillation, aperiodic (geostrophic) turbulence]. These general properties were first discovered in cylindrical (annular) systems, but they do not depend critically on geometry; differences between spherical and cylindrical systems are largely to be found in quantitative details. In all cases, the raison d'e tre of sloping convection is horizontal advective transfer, a process accompanied by upward advective heat transfer, which affects and may control vertical potential density gradients. It has been argued that sloping convection is the basic dynamical process underlying a wide variety of large-scale flow phenomena seen in planetary atmospheres (e.g., irregular waves in the Earth's atmosphere, regular waves in the Martian atmosphere, the Jovian Great Red Spot and other long-lived eddies seen in the atmospheres of the giant planets). In this review the extent to which this paradigm is upheld in the atmospheres of the major planets by recent work is discussed. PMID:12780096

  13. Light scattering by randomly oriented cubes and parallelepipeds. [for interpretation of observed data from planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Liou, K. N.; Cai, Q.; Pollack, J. B.; Cuzzi, J. N.

    1983-01-01

    In this paper, the geometric ray tracing theory for the scattering of light by hexagonal cylinders to cubes and parallelepipeds has been modified. Effects of the real and imaginary parts of the refractive index and aspect ratio of the particle on the scattering phase function and the degree of linear polarization are investigated. Causes of the physical features in the scattering polarization patterns are identified in terms of the scattering contribution due to geometric reflections and refractions. The single-scattering phase function and polarization data presented in this paper should be of some use for the interpretation of observed scattering and polarization data from planetary atmospheres and for the physical understanding of the transfer of radiation in an atmosphere containing nonspherical particles.

  14. Evidence for Water in the Rocky Debris of a Disrupted Extrasolar Minor Planet

    NASA Astrophysics Data System (ADS)

    Farihi, J.; Gänsicke, B. T.; Koester, D.

    2013-10-01

    The existence of water in extrasolar planetary systems is of great interest because it constrains the potential for habitable planets and life. We have identified a circumstellar disk that resulted from the destruction of a water-rich and rocky extrasolar minor planet. The parent body formed and evolved around a star somewhat more massive than the Sun, and the debris now closely orbits the white dwarf remnant of the star. The stellar atmosphere is polluted with metals accreted from the disk, including oxygen in excess of that expected for oxide minerals, indicating that the parent body was originally composed of 26% water by mass. This finding demonstrates that water-bearing planetesimals exist around A- and F-type stars that end their lives as white dwarfs.

  15. Infrared spectra of van de Waals complexes of importance in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Fraser, G. T.; Pine, A. S.; Lafferty, W. J.

    1990-01-01

    It has been suggested that (CO2)2 and Ar-CO2 are important constituents of the planetary atmospheres of Venus and Mars. Recent results on the laboratory spectroscopy of CO2 containing van der Waals complexes which may be of use in the modeling of the spectra of planetary atmospheres are presented. Sub-Doppler infrared spectra were obtained for (CO2)2, (CO2)3, and rare-gas-CO2 complexes in the vicinity of the CO2 Fermi diad at 2.7 micrometers using a color-center-laser optothermal spectrometer. From the spectroscopic constants the geometries of the complexes have been determined and van der Waals vibrational frequencies have been estimated. The equilibrium configurations are C2h, C3h, and C2v, for (CO2)2, (CO2)3, and the rare-gas-CO2 complexes, respectively. Most of the homogeneous linewidths for the revibrational transitions range from 0.5 to 22 MHz, indicating that predissociation is as much as four orders of magnitude faster than radiative processes for vibrational relaxation in these complexes.

  16. How do Atmospheres Affect Planetary Temperatures? Activity C Can we Model an Atmosphere's Effect Upon a Planet's Surface Temperature?

    NSDL National Science Digital Library

    2012-08-03

    In this activity, students simulate the interaction of variables, including carbon dioxide, in a radiation balance exercise using a spreadsheet-based radiation balance model. Through a series of experiments, students attempt to mimic the surface temperatures of Earth, Mercury, Venus and Mars, and account for the influence of greenhouse gases in atmospheric temperatures. The activity supports inquiry into the real-world problem of contemporary climate change. Student-collected data is needed from activity A in the same module, "How do atmospheres interact with solar energy?" to complete this activity. Included in the resource are several student data sheets and a teacher's guide. This activity is part of module 4, "How do Atmospheres Affect Planetary Temperatures?" in Earth Climate Course: What Determines a Planet's Climate? The course aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

  17. Extrasolar Visions

    NSDL National Science Digital Library

    The Extrasolar Visions Web site provides a searchable guide to extra solar planets. These include planets of normal stars, pulsar planets, brown dwarfs, protoplanetary disks and protoplanets, extragalactic worlds, massive compact halo objects, and disproven or doubtful worlds. Visitors can search for these objects or view the week's 20 most popular systems, 20 most interesting systems, or the 20 most recently updated systems. Once chosen, the objects name, mass, average distance, and type is given along with a link for further information. This well designed site does a good job of combining quality information and graphics resulting in a pleasurable surfing experience for anyone exploring it.

  18. Interactives: Comets, Orbital Motions, and Virtual Ballooning to Explore Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Russell, R. M.; Johnson, R. M.; Genyuk, J.

    2009-12-01

    We will demonstrate interactives and animations from the Windows to the Universe web site (www.windows.ucar.edu) covering three topics: cometary orbits and tails, orbit shapes and orbital motions, and virtual ballooning to explore planetary atmospheres. The comet interactive illustrates the range of shapes and sizes of cometary orbits, the formation of tails when a comet nears the Sun, and the orientations of the dust and ion tails. Our suite of animations and interactives about orbits and orbital motions help learners understand the shapes (eccentricity) and sizes (semi-major axis) of orbits as well as variations in orbital velocity from perihelion to aphelion. Our Mars orbit interactive illustrates the variations in distance between Earth and Mars as the planets orbit and at successive oppositions (closest approaches), which has influenced the history of both telescopic observations of the Red Planet as well as the timing of space missions to Mars. The virtual ballooning interactive enables students to explore the structures of atmospheres by launching virtual weather balloons that send back data on the variation of pressure and temperature with altitude. Learners set the altitude ranges and sampling frequencies for their balloon-borne virtual instruments and collect data over the course of four flights. Students learn about the pressure variation with altitude, temperature vs. altitude relationships in different atmospheric layers, and how to be thoughtful and selective during experimental data collection. Students can explore the atmospheres of Mars, Venus, and Titan as well as Earth.

  19. The molecular physics of photolytic fractionation of sulfur and oxygen isotopes in planetary atmospheres (Invited)

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Schmidt, J. A.; Hattori, S.; Danielache, S.; Meusinger, C.; Schinke, R.; Ueno, Y.; Nanbu, S.; Kjaergaard, H. G.; Yoshida, N.

    2013-12-01

    Atmospheric photochemistry is able to produce large mass independent anomalies in atmospheric trace gases that can be found in geological and cryospheric records. This talk will present theoretical and experimental investigations of the molecular mechanisms producing photolytic fractionation of isotopes with special attention to sulfur and oxygen. The zero point vibrational energy (ZPE) shift and reflection principle theories are starting points for estimating isotopic fractionation, but these models ignore effects arising from isotope-dependent changes in couplings between surfaces, excited state dynamics, line densities and hot band populations. The isotope-dependent absorption spectra of the isotopologues of HCl, N2O, OCS, CO2 and SO2 have been examined in a series of papers and these results are compared with experiment and ZPE/reflection principle models. Isotopic fractionation in planetary atmospheres has many interesting applications. The UV absorption of CO2 is the basis of photochemistry in the CO2-rich atmospheres of the ancient Earth, and of Mars and Venus. For the first time we present accurate temperature and isotope dependent CO2 absorption cross sections with important implications for photolysis rates of SO2 and H2O, and the production of a mass independent anomaly in the Ox reservoir. Experimental and theoretical results for OCS have implications for the modern stratospheric sulfur budget. The absorption bands of SO2 are complex with rich structure producing isotopic fractionation in photolysis and photoexcitation.

  20. Direct modeling of transiting planet light curves from model stellar atmospheres

    NASA Astrophysics Data System (ADS)

    Mcneil, Joseph; Neilson, H.; Ignace, R.

    2014-01-01

    Recent and new observations of extrasolar planets via the transit method are provided unparalleled measurements that enhance our understanding of both the planets and their host stars. However, analysis techniques assume simple parameters to describe the stellar intensity profile. In this work, we compare new planetary transit light curves computed directly from model stellar atmosphere intensity profiles with light curves computed using limb-darkening coefficients. This comparison highlights the need for better models of stellar intensities and atmospheres to better understand the extrasolar planets themselves, especially in the upcoming eras of TESS and PLATO.

  1. The Search for Extrasolar Earth-like planets

    E-print Network

    S. Seager

    2003-05-19

    The search for extrasolar Earth-like planets is underway. Over 100 extrasolar giant planets are known to orbit nearby sun-like stars, including several in multiple-planet systems. These planetary systems are stepping stones for the search for Earth-like planets; the technology development, observational strategies, and science results can all be applied to Earth-like planets. Stars much less massive than the sun the most common stars in our Galaxy are being monitored for the gravitational influence of Earth-like planets. Although Earth-like planets orbiting sun-like stars are much more difficult to detect, space missions are being built to detect them indirectly due to their effects on the parent star and to quantify fundamental factors such as terrestrial planet frequency, size distribution, and mass distribution. Extremely ambitious space programs are being developed to directly detect Earth-like planets orbiting sun-like stars, and must tackle the immense technological challenge of blocking out the light of the parent star, which is brighter than the planet by six to ten orders of magnitude. Direct detection of radiation from the planet is necessary for the definitive goal of the search for Earth-like planets: the study of atmospheric spectral signatures for signs of severe disequilibrium chemistry that could be indicative of biological activity. In addition to technological development, a growing flurry of scientific activity has begun to: understand terrestrial planet formation and terrestrial planet frequency; model terrestrial-like planet atmospheres and evolution; articulate the biological signatures of our own Earth; and even to study Earth as an extrasolar planet by observation and analysis of the spatially unresolved Earth.

  2. Microlensing Searches for Extrasolar Planets

    E-print Network

    Gaudi, B. Scott

    Microlensing Searches for Extrasolar Planets Microlensing Searches for Extrasolar Planets I for Extrasolar Planets, B. Scott Gaudi, IAS #12;The Search for Extrasolar PlanetsThe Search for Extrasolar Planets Why Search for Extrasolar Planets ? Frequency of Life Clues to Star Formation Low End

  3. UV Photoabsorption Cross Sections of CO, N2, and SO2 for Studies of the ISM and Planetary Atmospheres

    Microsoft Academic Search

    Peter L. Smith; J. Rufus; K. Yoshino; W. H. Parkinson; Glenn Stark; J. C. Pickering; A. P. Thorne

    2002-01-01

    We report on high-resolution laboratory measurements of photoabsorption cross sections of simple molecules in the wavelength range 80 to 320 nm. The motivation is to provide the quantitative data that are needed to analyze observations of absorption by, and to model photochemical processes in the interstellar medium and a number of planetary atmospheres. Because of the high resolution of the

  4. The solar wind interaction with Mars: Recent progress and future directions The Sun has a powerful influence on planetary atmospheres.

    E-print Network

    California at Berkeley, University of

    Editorial The solar wind interaction with Mars: Recent progress and future directions The Sun has a powerful influence on planetary atmospheres. This is especially true for planets lacking a global magnetic field, because the solar wind can interact directly with the upper atmo- sphere. Neutral particles

  5. Internal variability of the tropical Pacific ocean Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

    E-print Network

    Jochum, Markus

    Internal variability of the tropical Pacific ocean M. Jochum Earth, Atmospheric and Planetary model of the tropical Pacific ocean is analyzed to quantify the interannual variability caused by internal variability of ocean dynamics. It is found that along the Pacific cold tongue internal variability

  6. Water Planetary and Cometary Atmospheres: H2O/HDO Transmittance and Fluorescence Models

    NASA Technical Reports Server (NTRS)

    Villanueva, G. L.; Mumma, M. J.; Bonev, B. P.; Novak, R. E.; Barber, R. J.; DiSanti, M. A.

    2012-01-01

    We developed a modern methodology to retrieve water (H2O) and deuterated water (HDO) in planetary and cometary atmospheres, and constructed an accurate spectral database that combines theoretical and empirical results. Based on a greatly expanded set of spectroscopic parameters, we built a full non-resonance cascade fluorescence model and computed fluorescence efficiencies for H2O (500 million lines) and HDO (700 million lines). The new line list was also integrated into an advanced terrestrial radiative transfer code (LBLRTM) and adapted to the CO2 rich atmosphere of Mars, for which we adopted the complex Robert-Bonamy formalism for line shapes. We then retrieved water and D/H in the atmospheres of Mars, comet C/2007 WI, and Earth by applying the new formalism to spectra obtained with the high-resolution spectrograph NIRSPEC/Keck II atop Mauna Kea (Hawaii). The new model accurately describes the complex morphology of the water bands and greatly increases the accuracy of the retrieved abundances (and the D/H ratio in water) with respect to previously available models. The new model provides improved agreement of predicted and measured intensities for many H2O lines already identified in comets, and it identifies several unassigned cometary emission lines as new emission lines of H2O. The improved spectral accuracy permits retrieval of more accurate rotational temperatures and production rates for cometary water.

  7. Linear relationships between root-zone soil moisture and atmospheric processes in the planetary boundary layer

    NASA Astrophysics Data System (ADS)

    Basara, Jeffrey B.; Crawford, Kenneth C.

    2002-08-01

    Soil moisture modulates the exchange of mass and energy between the atmosphere and the land surface. This study focuses on the relationship between soil moisture and atmospheric processes at and near the Norman Mesonet site using both automated and field samples of hydrologic and atmospheric parameters. During 1999, measurements were made during an intensive observing period (IOP) that spanned the dates of 1 June to 12 August. Analysis of the observations revealed 13 days were characterized by strong radiative forcing and weak shear in the lower troposphere (defined as ideal or golden days). Though the total number of ideal study days was somewhat limited, observations were collected over a wide range of atmospheric and soil moisture conditions. The results of this study demonstrate that soil water content in the root-zone at the Norman Mesonet site during the summer of 1999 was linearly correlated with daily-maximum values of sensible heat flux and latent heat flux on ideal days. Furthermore, the relationship between the mean evaporative fraction calculated during daylight hours and soil water in the root-zone was strong and linear. However, the relationship between soil water in the surface layer and the mean evaporative fraction was weak and nonlinear. Significant linear relationships were also found to exist between soil water in the root-zone and atmospheric parameters in the planetary boundary layer including the daily maximum air temperature at 1.5 m, mean potential temperature in the 925-850 mbar layer, mixing ratio at 1.5 m, and mean mixing ratio in the 925-850 mbar layer.

  8. Proposal for constructing an advanced software tool for planetary atmospheric modeling

    NASA Technical Reports Server (NTRS)

    Keller, Richard M.; Sims, Michael H.; Podolak, Esther; Mckay, Christopher P.; Thompson, David E.

    1990-01-01

    Scientific model building can be a time intensive and painstaking process, often involving the development of large and complex computer programs. Despite the effort involved, scientific models cannot easily be distributed and shared with other scientists. In general, implemented scientific models are complex, idiosyncratic, and difficult for anyone but the original scientist/programmer to understand. We believe that advanced software techniques can facilitate both the model building and model sharing process. We propose to construct a scientific modeling software tool that serves as an aid to the scientist in developing and using models. The proposed tool will include an interactive intelligent graphical interface and a high level, domain specific, modeling language. As a testbed for this research, we propose development of a software prototype in the domain of planetary atmospheric modeling.

  9. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, P. G.

    1986-01-01

    After long arduous work with the simulator, measurements of the refractivity and absorptivity of nitrogen under conditions similar to those for Titan were completed. The most significant measurements, however, were those of the microwave absorption from gaseous ammonia under simulated conditions for the Jovian atmospheres over wavelengths from 1.3 to 22 cm. The results of these measurements are critical in that they confirm the theoretical calculation of the ammonia opacity using the Ben-Reuven lineshape. The application of both these results, and results obtained previously, to planetary observations at microwave frequencies were especially rewarding. Applications of the results for ammonia to radio astronomical observations of Jupiter in the 1.3 to 20 cm wavelength range and the application of results for gaseous H2SO4 under simulated Venus conditions are discussed.

  10. Vapor pressure isotope fractionation effects in planetary atmospheres: application to deuterium

    E-print Network

    Thierry Fouchet; Emmanuel Lellouch

    1999-11-15

    The impact of the vapor pressure difference between deuterated and nondeuterated condensing molecules in planetary atmospheres is quantitatively assessed. This difference results in a loss of deuterium in the vapor phase above the condensation level. In Titan, Uranus and Neptune, the effect on CH3D is too subtle to alter current D/H ratio determinations. In Mars, the effect can induce a large depletion of HDO, starting about one scale height above the condensation level. Although the current infrared measurements of the D/H ratio appear to be almost unaffected, the intensity of disk-averaged millimetric HDO lines can be modified by about 10%. The effect is much stronger in limb sounding, and can be easily detected from orbiter observations.

  11. Electron conic distributions produced by solar ionizing radiation in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Peterson, W. K.; Brain, D. L.; Yau, A. W.; Richards, P. G.

    2015-06-01

    Electron conic distributions have angular distributions with peak fluxes well separated from the field aligned-direction. They have previously been reported at Earth on auroral field lines and at the Moon and Mars on closed crustal magnetic field lines. Here we report observations of electron conics at Earth on closed magnetic field lines well removed from the aurora. We show how these distributions could be produced without plasma wave interactions when magnetic field lines are illuminated by solar ionizing radiation at relatively high altitudes in the ionosphere. Examination of previous reports of electron conic distributions observed in planetary atmospheres show that there are a variety of physical mechanisms that can lead to their formation, not all of which require wave-particle interactions.

  12. Submillimeter Remote Sensing of Planetary and Cometary Atmospheres and LRO/LCROSS Observations of the Moon

    NASA Technical Reports Server (NTRS)

    Chin, Gordon

    2011-01-01

    Submillimeter remote sensing of planetary and cometary atmospheres have been proposed for Venus and Mars while MIRO on Rosetta will observe the coma of Comet 67P/Churyumov - Cierasimenko in December 2015, UARS and AURA MLS have observed millimeter and submillimeter molecule emissions in the Earth's stratosphere for many decades, Observations of submillimeter wave molecular emissions provide a wealth of information not obtainable by alternative techniques. Submillimeter line emissions exhibit linear temperature dependence, insensitivity to aerosol scattering, extinction, and have separated transitions with well determined line-shapes. These observations have high sensitivities to trace chemical species and can; 1) Fully resolve the line profiles of molecules with high resolution, 2) Provide deterministic retrievals of species abundance, temperature, and pressure, and 3) Measure Doppler shifts of detected molecules for wind velocities.

  13. Proposal for constructing an advanced software tool for planetary atmospheric modeling

    NASA Astrophysics Data System (ADS)

    Keller, Richard M.; Sims, Michael H.; Podolak, Esther; McKay, Christopher P.; Thompson, David E.

    1990-03-01

    Scientific model building can be a time intensive and painstaking process, often involving the development of large and complex computer programs. Despite the effort involved, scientific models cannot easily be distributed and shared with other scientists. In general, implemented scientific models are complex, idiosyncratic, and difficult for anyone but the original scientist/programmer to understand. We believe that advanced software techniques can facilitate both the model building and model sharing process. We propose to construct a scientific modeling software tool that serves as an aid to the scientist in developing and using models. The proposed tool will include an interactive intelligent graphical interface and a high level, domain specific, modeling language. As a testbed for this research, we propose development of a software prototype in the domain of planetary atmospheric modeling.

  14. Using the transit of Venus to probe the upper planetary atmosphere.

    PubMed

    Reale, Fabio; Gambino, Angelo F; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-01-01

    During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultraviolet and soft X-rays with Hinode and Solar Dynamics Observatory missions. We find that, while Venus's optical radius is about 80?km larger than the solid body radius (the top of clouds and haze), the radius increases further by >70?km in the extreme ultraviolet and soft X-rays. This measures the altitude of the densest ion layers of Venus's ionosphere (CO2 and CO), useful for planning missions in situ, and a benchmark case for detecting transits of exoplanets in high-energy bands with future missions, such as the ESA Athena. PMID:26102562

  15. Noble gas isotopic composition as a key reference parameter in a planetary atmospheric evolution model

    NASA Astrophysics Data System (ADS)

    Ozima, M.

    2010-12-01

    The isotopic composition of noble gases is a key reference parameter in discussing the evolution of planetary atmospheres. Currently, two widely occurring noble gas components are identified in the early solar system, one is the Solar Wind noble gas (SW-noble gas, hereafter) and another is the Q-noble gas in unaltered meteorites: both noble gases are characterized by their ubiquitous occurrence and high isotopic homogeneity. Since the SW-noble gas is directly ejected from the Sun, it has been assumed to be a good proxy of the average noble gas isotopic composition in the Sun, namely the solar noble gas. The systematic enrichment of the heavier isotopes in the Q-noble gas relative to the SW-noble gas is then commonly attributed to its isotopic fractionation from the SW-noble gas. However, the isotopic compositions of the SW-noble gas either implanted on lunar soils or trapped by artificial targets show considerable isotopic variation depending on the velocity of the Solar Wind. Therefore, it is important to examine how closely the SW-noble gas represents the indigenous solar noble gas component or the mean isotopic composition of noble gases of the Sun. Here we show that the isotopic composition of the SW-noble gas is substantially fractionated relative to the solar value, and therefore should not be used as a reference parameter. We further suggest that the post D-burning Q-noble gas (see below) is the better proxy of the solar noble gas, and this should be used as a reference of the Solar noble gas isotopic composition in discussing the planetary atmospheric evolution. The most distinct difference between the Q- and the SW-noble gas is apparent in a 3He/4He isotopic ratio: 4.64e-4 in Q-He [1], but 1.23e-4 in SW-He[2]. The difference is attributed to the conversion of deuteron (D) to 3He in the Sun, namely the D-burning [3], due to high temperature during the pre-main sequence stage of the Sun. With the use of recent data on D/H ratios from helio-seismology [4] and spectroscopic observation of the inter-stellar cloud [5], we estimated that the 3He/4He ratio in the post D-burning He in the Sun is 3.98e-4. The latter value is considerably smaller than the recent estimate of the SW-He ratio by the GENESIS mission of 3He/4He = 4.64e-4 [2]. We conclude that this difference is due to isotopic fractionation during the ejection of the Solar Wind from the solar atmosphere. The further interesting implication of this conclusion is that the marked difference in 3He/4He between the SW- and Q-noble gases can be used as an unique chronological marker in the planetary atmospheric evolution. [1] Busemann H. et al., Meteoritics & Planetary Science, 35, 949-973, 2000. [2] Heber V. et al. Geochimica Cosmochimica Acta, 73, 7414-7432, 2009. [3] Geiss J. and Reeve H. Astronomy Astrophysics, 18, 126-132, 1972. [4] Basu S. and Antia H.M. Astrophysical J. , 606:L85-L88, 2004. [5] Linsky J.L. et al. Astrophysical J., 647:1106-1124, 2006.

  16. Theortetical Models of Extrasolar Giant Planets

    E-print Network

    A. Burrows; W. B. Hubbard; J. I. Lunine; T. Guillot; D. Saumon; M. Marley; R. S. Freedman

    1996-08-28

    The recent discoveries of giant planets around nearby stars have galvanized the planetary science community, astronomers, and the public at large. Since {\\it direct} detection is now feasible, and is suggested by the recent acquisition of Gl229 B, it is crucial for the future of extrasolar planet searches that the fluxes, evolution, and physical structure of objects from Saturn's mass to 15 Juipter masses be theoretically investigated. We discuss our first attempts to explore the characteristics of extrasolar giant planets (EGPs), in aid of both NASA's and ESA's recent plans to search for such planets around nearby stars.

  17. A method for the direct determination of the surface gravities of transiting extrasolar planets

    E-print Network

    John Southworth; Peter J. Wheatley; Giles Sams

    2007-04-12

    We show that the surface gravity of a transiting extrasolar planet can be calculated from only the spectroscopic orbit of its parent star and the analysis of its transit light curve. This does not require additional constraints, such as are often inferred from theoretical stellar models or model atmospheres. The planet's surface gravity can therefore be measured precisely and from only directly observable quantities. We outline the method and apply it to the case of the first known transiting extrasolar planet, HD 209458b. We find a surface gravity of g_p = 9.28 +/- 0.15 m/s, which is an order of magnitude more precise than the best available measurements of its mass, radius and density. This confirms that the planet has a much lower surface gravity that that predicted by published theoretical models of gas giant planets. We apply our method to all fourteen known transiting extrasolar planets and find a significant correlation between surface gravity and orbital period, which is related to the known correlation between mass and period. This correlation may be the underlying effect as surface gravity is a fundamental parameter in the evaporation of planetary atmospheres.

  18. Extrasolar Planets: A Galactic Perspective

    E-print Network

    I. N. Reid

    2006-08-15

    The host stars of extrasolar planets tend to be metal-rich. We have examined the data for these stars for evidence of trends in other galactic parameters, without success. However, several ESP hosts are likely to be members of the thick disk population, indicating that planet formation has occurred throughout the full lifetime of the Galactic disk. We briefly consider the radial metallicity gradient and age-metallicity relation of the Galactic disk, and complete a back-of-the envelope estimate of the likely number of solar-type stars with planetary companions with 6 < R < 10 kpc.

  19. Aerial Vehicle Surveys of other Planetary Atmospheres and Surfaces: Imaging, Remote-sensing, and Autonomy Technology Requirements

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Pisanich, Gregory; Ippolito, Corey; Alena, Rick

    2005-01-01

    The objective of this paper is to review the anticipated imaging and remote-sensing technology requirements for aerial vehicle survey missions to other planetary bodies in our Solar system that can support in-atmosphere flight. In the not too distant future such planetary aerial vehicle (a.k.a. aerial explorers) exploration missions will become feasible. Imaging and remote-sensing observations will be a key objective for these missions. Accordingly, it is imperative that optimal solutions in terms of imaging acquisition and real-time autonomous analysis of image data sets be developed for such vehicles.

  20. Formation, Habitability, and Detection of Extrasolar Moons

    E-print Network

    Heller, René; Kipping, David; Limbach, Mary Anne; Turner, Edwin; Greenberg, Richard; Sasaki, Takanori; Bolmont, Émeline; Grasset, Olivier; Lewis, Karen; Barnes, Rory; Zuluaga, Jorge I

    2014-01-01

    The diversity and quantity of moons in the Solar System suggest a manifold population of natural satellites exist around extrasolar planets. Of peculiar interest from an astrobiological perspective, the number of sizable moons in the stellar habitable zones may outnumber planets in these circumstellar regions. With technological and theoretical methods now allowing for the detection of sub-Earth-sized extrasolar planets, the first detection of an extrasolar moon appears feasible. In this review, we summarize formation channels of massive exomoons that are potentially detectable with current or near-future instruments. We discuss the orbital effects that govern exomoon evolution, we present a framework to characterize an exomoon's stellar plus planetary illumination as well as its tidal heating, and we address the techniques that have been proposed to search for exomoons. Most notably, we show that natural satellites in the range of 0.1 - 0.5 Earth mass (i) are potentially habitable, (ii) can form within the c...

  1. Habitable extrasolar planets: from theory to observations

    NASA Astrophysics Data System (ADS)

    Haghighipour, N.

    The discovery of planets around other stars is undoubtedly one of the most significant achievements of modern astronomy. The detection of more than 700 extrasolar planets combined with more than 2300 planetary candidates identified by the Kepler space telescope has proven the fact that our solar system is not unique and many planets, in particular those similar to our Earth, may exist elsewhere in the universe. Although the detection of an Earth-sized planet in the habitable zone of a Sun-like star is still a chal- lenging task, astronomers have been able to identify slightly larger objects known as super-Earths in the habitable zones of M stars. These objects, with their capability in retaining a moderate atmosphere, a possible dynam- ics interior, and a magnetic field, present promising venues for searching for habitable planets. This paper presents a short review of the current state of research on the formation of Earth-sized planets and super-Earths, and their detection around low-mass stars.

  2. ExtraSolar Planets Finding Extrasolar Planets. I

    E-print Network

    Walter, Frederick M.

    ExtraSolar Planets #12;Finding Extrasolar Planets. I Direct Searches Direct searches are difficult #12;Finding Extrasolar Planets. II Transits #12;Transits Transits requires an edge-on orbit. ·Jupiter;How Transits Work #12;Finding Extrasolar Planets. III Astrometric Wobble #12;Finding Extrasolar

  3. SURVEY FOR TRANSITING EXTRASOLAR PLANETS IN STELLAR SYSTEMS. III. A LIMIT ON THE FRACTION OF STARS WITH PLANETS IN THE OPEN CLUSTER NGC 1245

    E-print Network

    Gaudi, B. Scott

    SURVEY FOR TRANSITING EXTRASOLAR PLANETS IN STELLAR SYSTEMS. III. A LIMIT ON THE FRACTION OF STARS photometric search for transiting extrasolar planets in the open cluster NGC 1245. An automated transit search: individual (NGC 1245) -- planetary systems 1. INTRODUCTION Extrasolar planet detections and analysis

  4. Detection of Extrasolar Planets by Transit Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William; Koch, David; Webster, Larry; Dunham, Edward; Witteborn, Fred; Jenkins, Jon; Caldwell, Douglas; Showen, Robert; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    A knowledge of other planetary systems that includes information on the number, size, mass, and spacing of the planets around a variety of star types is needed to deepen our understanding of planetary system formation and processes that give rise to their final configurations. Recent discoveries show that many planetary systems are quite different from the solar system in that they often possess giant planets in short period orbits. The inferred evolution of these planets and their orbital characteristics imply the absence of Earth-like planets near the habitable zone. Information on the properties of the giant-inner planets is now being obtained by both the Doppler velocity and the transit photometry techniques. The combination of the two techniques provides the mass, size, and density of the planets. For the planet orbiting star HD209458, transit photometry provided the first independent confirmation and measurement of the diameter of an extrasolar planet. The observations indicate a planet 1.27 the diameter of Jupiter with 0.63 of its mass (Charbonneau et al. 1999). The results are in excellent agreement with the theory of planetary atmospheres for a planet of the indicated mass and distance from a solar-like star. The observation of the November 23, 1999 transit of that planet made by the Ames Vulcan photometer at Lick Observatory is presented. In the future, the combination of the two techniques will greatly increase the number of discoveries and the richness of the science yield. Small rocky planets at orbital distances from 0.9 to 1.2 AU are more likely to harbor life than the gas giant planets that are now being discovered. However, new technology is needed to find smaller, Earth-like planets, which are about three hundred times less massive than Jupiter-like planets. The Kepler project is a space craft mission designed to discover hundreds of Earth-size planets in and near the habitable zone around a wide variety of stars. To demonstrate that the technology exists to find such small planets, our group has conducted an end-to-end system test. The results of the laboratory tests are presented and show that we are ready to start the search for Earth-size planets.

  5. Tidal interactions of close-in extrasolar planets with their central star

    Microsoft Academic Search

    M. Pätzold; H. Rauer

    2003-01-01

    Many extrasolar planets have been discovered very close to sun-like stars (<0.1 AU). These planets are exposed to extreme tidal interactions with the star. We review several aspects of tidal interactions as orbit evolution and circularisation, the tidal locking of planetary rotation and revolution, and changes in the stellar rotation. These concepts are applied to the known extrasolar planets with

  6. Extrasolar planet taxonomy: a new statistical approach

    E-print Network

    Simone Marchi

    2007-05-07

    In this paper we present the guidelines for an extrasolar planet taxonomy. The discovery of an increasing number of extrasolar planets showing a vast variety of planetary parameters, like Keplerian orbital elements and environmental parameters, like stellar masses, spectral types, metallicity etc., prompts the development of a planetary taxonomy. In this work via principal component analysis followed by hierarchical clustering analysis, we report the definition of five robust groups of planets. We also discuss the physical relevance of such analysis, which may provide a valid basis for disentangling the role of the several physical parameters involved in the processes of planet formation and subsequent evolution. For instance, we were able to divide the hot Jupiters into two main groups on the basis of their stellar masses and metallicities. Moreover, for some groups, we find strong correlations between metallicity, semi-major axis and eccentricity. The implications of these findings are discussed.

  7. Search for hydrogen peroxide in the Martian atmosphere by the Planetary Fourier Spectrometer onboard Mars Express

    NASA Astrophysics Data System (ADS)

    Aoki, Shohei; Giuranna, Marco; Kasaba, Yasumasa; Nakagawa, Hiromu; Sindoni, Giuseppe; Geminale, Anna; Formisano, Vittorio

    2015-01-01

    We searched for hydrogen peroxide (H2O2) in the Martian atmosphere using data measured by the Planetary Fourier Spectrometer (PFS) onboard Mars Express during five martian years (MY27-31). It is well known that H2O2 plays a key role in the oxidizing capacity of the Martian atmosphere. However, only a few studies based on ground-based observations can be found in the literature. Here, we performed the first analysis of H2O2 using long-term measurements by a spacecraft-borne instrument. We used the ?4 band of H2O2 in the spectral range between 359 cm-1 and 382 cm-1 where strong features of H2O2 are present around 362 cm-1 and 379 cm-1. Since the features were expected to be very weak even at the strong band, sensitive data calibrations were performed and a large number of spectra were selected and averaged. We made three averaged spectra for different seasons over relatively low latitudes (50°S-50°N). We found features of H2O2 at 379 cm-1, whereas no clear features were detected at 362 cm-1 due to large amounts of uncertainty in the data. The derived mixing ratios of H2O2 were close to the detection limits: 16 ± 19 ppb at Ls = 0-120°, 35 ± 32 ppb at Ls = 120-240°, and 41 ± 28 ppb at Ls = 240-360°. The retrieved value showed the detection of H2O2 only for the third seasonal period, and the values in the other periods provided the upper limits. These long-term averaged abundances derived by the PFS generally agreed with the ones reported by ground-based observations. From our derived mixing ratio of H2O2, the lifetime of CH4 in the Martian atmosphere is estimated to be several decades in the shortest case. Our results and sporadic detections of CH4 suggest the presence of strong CH4 sinks not subject to atmospheric oxidation.

  8. Computing planetary atmospheres with algorithms derived from action thermodynamics and a novel version of the virial theorem for gravitating polyatomic molecules

    E-print Network

    Kennedy, Ivan R

    2015-01-01

    An objective revision of the Laplace barometric formula for isothermal planetary atmospheres is proposed. From Clausius virial theorem equating the root mean square kinetic energy to half the gravitational potential energy, planetary atmospheres are required to have declining temperature with altitude as a consequence of the interaction between thermodynamic heat flow and gravity. The virial action hypothesis predicts non adiabatic lapse rates in temperature yielding a practical means to calculate variations with altitude in atmospheric entropy, free energy, molecular density and pressure. Remarkably, the new formulae derived enable prediction of atmospheric profiles with physical properties closely resembling those observed on Earth, Venus and Mars. These new formulae provide an objective basis for computing the dynamic morphology of the atmosphere. Climate scientists may consider this explanatory hypothesis for self organisation of planetary atmospheres for its possible relevance for predicting global surfa...

  9. Dynamical relaxation and massive extrasolar planets

    Microsoft Academic Search

    John C. B. Papaloizou; Caroline Terquem

    2001-01-01

    Following the suggestion of BlackQ1 that some massive extrasolar planets may be associated with the tail of the distribution of stellar companions, we investigate a scenario in which 5<=N<=100 planetary mass objects are assumed to form rapidly through a fragmentation process occuring in a disc or protostellar envelope on a scale of 100au. These are assumed to have formed rapidly

  10. Planetas extrasolares con pequeño semieje orbital

    Microsoft Academic Search

    D. Giuliodori; S. Fernández

    2002-01-01

    The discovery of extra-solar planets, first surrounding a pulsar (PSR1257+12, Malhotra et al 1992) and then main-sequence stars similar to our sun, (http:\\/\\/exoplanets.org) has opened a new field of study inside the dynamic of planetary systems. Although the information we have of these objects is determined by the own limitations of the detection methods that are used, important differences between

  11. A statistical mechanics barotropic energy-enstrophy theory for super-rotation in planetary atmospheres

    E-print Network

    Lim, Chjan C.

    A statistical mechanics barotropic energy-enstrophy theory for super-rotation in planetary and Computational Science, National university of Singapore September 30 2000 Abstract A statistical mechanics

  12. The aurora as a source of planetary-scale waves in the middle atmosphere. [atmospheric turbulence caused by auroral energy absorption

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Straus, J. M.

    1974-01-01

    Photographs of global scale auroral forms taken by scanning radiometers onboard weather satellites in 1972 show that auroral bands exhibit well organized wave motion with typical zonal wave number of 5 or so. The scale size of these waves is in agreement with that of well organized neutral wind fields in the 150- to 200-km region during the geomagnetic storm of May 27, 1967. Further, the horizontal scale size revealed by these observations are in agreement with that of high altitude traveling ionospheric disturbances. It is conjectured that the geomagnetic storm is a source of planetary and synoptic scale neutral atmospheric waves in the middle atmosphere. Although there is, at present, no observation of substorm related waves of this scale size at mesospheric and stratospheric altitudes, the possible existence of a new source of waves of the proper scale size to trigger instabilities in middle atmospheric circulation systems may be significant in the study of lower atmospheric response to geomagnetic activity.

  13. Planetary Systems and the Origins of Life

    NASA Astrophysics Data System (ADS)

    Pudritz, Ralph; Higgs, Paul; Stone, Jonathon

    2013-01-01

    Preface; Part I. Planetary Systems and the Origins of Life: 1. Observations of extrasolar planetary systems Shay Zucker; 2. The atmospheres of extrasolar planets L. Jeremy Richardson and Sara Seager; 3. Terrestrial planet formation Edward Thommes; 4. Protoplanetary disks, amino acids and the genetic code Paul Higgs and Ralph Pudritz; 5. Emergent phenomena in biology: the origin of cellular life David Deamer; Part II. Life on Earth: 6. Extremophiles: defining the envelope for the search for life in the Universe Lynn Rothschild; 7. Hyperthermophilic life on Earth - and on Mars? Karl Stetter; 8. Phylogenomics: how far back in the past can we go? Henner Brinkmann, Denis Baurain and Hervé Philippe; 9. Horizontal gene transfer, gene histories and the root of the tree of life Olga Zhaxybayeva and J. Peter Gogarten; 10. Evolutionary innovation versus ecological incumbency Adolf Seilacher; 11. Gradual origins for the Metazoans Alexandra Pontefract and Jonathan Stone; Part III. Life in the Solar System?: 12. The search for life on Mars Chris McKay; 13. Life in the dark dune spots of Mars: a testable hypothesis Eörs Szathmary, Tibor Ganti, Tamas Pocs, Andras Horvath, Akos Kereszturi, Szaniszlo Berzci and Andras Sik; 14. Titan: a new astrobiological vision from the Cassini-Huygens data François Raulin; 15. Europa, the Ocean Moon: tides, permeable ice, and life Richard Greenberg; Index.

  14. Planetary Surface Instruments Workshop

    NASA Technical Reports Server (NTRS)

    Meyer, Charles (Editor); Treiman, Allan H. (Editor); Kostiuk, Theodor (Editor)

    1996-01-01

    This report on planetary surface investigations and planetary landers covers: (1) the precise chemical analysis of solids; (2) isotopes and evolved gas analyses; (3) planetary interiors; planetary atmospheres from within as measured by landers; (4) mineralogical examination of extraterrestrial bodies; (5) regoliths; and (6) field geology/processes.

  15. Bok Prize Lecture (shared) Towards a Physical Characterization of Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Seager, Sara

    2004-03-01

    We have entered a new era in planetary astrophysics with well over 100 giant planets now known to orbit nearby sun-like stars. Recent theoretical and observational advances have given us new constraints on the physical characteristics of extrasolar planets, while ongoing and proposed observing programs and space missions hold great promise for the future of extrasolar planet science. I will discuss the emerging understanding of the extrasolar transiting planet HD209458b, tying together several recent observational constraints as well as key upcoming measurements.I will also briefly review scientific highlights and prospects for the future detection and study of Earth-like extrasolar planets.

  16. Storms and Variability on Tidally-Locked Extrasolar Planets

    Microsoft Academic Search

    James Cho

    2010-01-01

    Transiting extrasolar planets are expected to be in a tidally-synchronized, 1:1 spin-orbit state. Currently, the flow and temperature structures of these planets -- needed to characterize them -- are not known. General circulation simulations of the lower atmospheric region (~1 bar to ~1 mbar) on tidally-locked extrasolar planets show a surprisingly homogeneous temperature distribution over large height ranges. The atmospheres

  17. ATMOSPHERIC CIRCULATION OF ECCENTRIC HOT NEPTUNE GJ436b

    SciTech Connect

    Lewis, Nikole K.; Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Marley, Mark S.; Freedman, Richard S. [NASA Ames Research Center 245-3, Moffett Field, CA 94035 (United States); Lodders, Katharina, E-mail: nlewis@lpl.arizona.ed [Washington University, One Brookings Drive, St. Louis, MO 63130 (United States)

    2010-09-01

    GJ436b is a unique member of the transiting extrasolar planet population being one of the smallest and least irradiated and possessing an eccentric orbit. Because of its size, mass, and density, GJ436b could plausibly have an atmospheric metallicity similar to Neptune (20-60 times solar abundances), which makes it an ideal target to study the effects of atmospheric metallicity on dynamics and radiative transfer in an extrasolar planetary atmosphere. We present three-dimensional atmospheric circulation models that include realistic non-gray radiative transfer for 1, 3, 10, 30, and 50 times solar atmospheric metallicity cases of GJ436b. Low metallicity models (1 and 3 times solar) show little day/night temperature variation and strong high-latitude jets. In contrast, higher metallicity models (30 and 50 times solar) exhibit day/night temperature variations and a strong equatorial jet. Spectra and light curves produced from these simulations show strong orbital phase dependencies in the 50 times solar case and negligible variations with orbital phase in the 1 times solar case. Comparisons between the predicted planet/star flux ratio from these models and current secondary eclipse measurements support a high metallicity atmosphere (30-50 times solar abundances) with disequilibrium carbon chemistry at play for GJ436b. Regardless of the actual atmospheric composition of GJ436b, our models serve to illuminate how metallicity influences the atmospheric circulation for a broad range of warm extrasolar planets.

  18. Photochemical abiotic synthesis of amino-acid precursors from simulated planetary atmospheres by vacuum ultraviolet light

    SciTech Connect

    Takahashi, Jun-ichi; Masuda, Hitomi; Kaneko, Takeo; Kobayashi, Kensei; Saito, Takeshi; Hosokawa, Teruo [Nippon Telegraph and Telephone Corporation (NTT) Microsystem Integration Laboratories, 3-I Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501 (Japan); Institute for Cosmic Ray Research, The University of Tokyo, 3-2-1 Midori-cho, Tanashi, Tokyo 188-8502 (Japan); NTT Electronics, Co. Ltd., 1841-I, Tsuruma, Machida, Tokyo 194-0004 (Japan)

    2005-07-15

    For the purpose of investigating the photon energy dependence of the photoinduced abiotic synthesis of organic molecules, gas mixtures that simulate typical planetary atmospheres, including a carbon source (CO or CH{sub 4}), a nitrogen source (N{sub 2} or NH{sub 3}), and H{sub 2}O, were irradiated with synchrotron radiation through a vacuum-ultraviolet transmitting window. Three kinds of window material, fused silica, synthetic quartz, and MgF{sub 2}, were used as a high-energy-cutting filter, whose absorption-edge energies are 6.4, 8.1, and 10.5 eV, respectively. Three types of gas mixture, Titan-type (CH{sub 4}-N{sub 2}-H{sub 2}O), comet-type (CO-NH{sub 3}-H{sub 2}O), and primitive-Earth-type (CO-N{sub 2}-H{sub 2}O), were irradiated with vacuum-ultraviolet photons in the three energy ranges. After the irradiation, amino-acid formation yields in the acid-hydrolyzed solution of the product were measured with a high-performance liquid chromatograph method. From the Titan- and comet-type mixtures, amino acids were detected by irradiation with photons lower than 8.1 eV. For both mixtures, the averaged quantum yields of glycine generation in the photon energy region of 7-10.5 eV were of the order of 10{sup -5}, which was larger by about one order than that in the region 5-8 eV. On the other hand, from the primitive-Earth-type mixture, amino-acid formation was difficult to detect even with irradiation as high as 10.5 eV, even though amino acids were generated in comparable yields from the Titan- and comet-type mixtures by irradiation with soft x rays or proton beam, whose energies are much higher. These results suggest that the vacuum ultraviolet light is a more effective energy source for the generation of the precursors of bioorganic compounds in extraterrestrial environments than in primitive-Earth atmosphere.

  19. Characterization of Extrasolar Planets Using SOFIA

    NASA Technical Reports Server (NTRS)

    Deming, Drake

    2010-01-01

    Topics include: the landscape of extrasolar planets, why focus on transiting planets, some history and Spitzer results, problems in atmospheric structure or hot Jupiters and hot super Earths, what observations are needed to make progress, and what SOFIA can currently do and comments on optimized instruments.

  20. Analytic evaluation of the weighting functions for remote sensing of blackbody planetary atmospheres : the case of limb viewing geometry

    NASA Technical Reports Server (NTRS)

    Ustinov, Eugene A.

    2006-01-01

    In a recent publication (Ustinov, 2002), we proposed an analytic approach to evaluation of radiative and geophysical weighting functions for remote sensing of a blackbody planetary atmosphere, based on general linearization approach applied to the case of nadir viewing geometry. In this presentation, the general linearization approach is applied to the limb viewing geometry. The expressions, similar to those obtained in (Ustinov, 2002), are obtained for weighting functions with respect to the distance along the line of sight. Further on, these expressions are converted to the expressions for weighting functions with respect to the vertical coordinate in the atmosphere. Finally, the numerical representation of weighting functions in the form of matrices of partial derivatives of grid limb radiances with respect to the grid values of atmospheric parameters is used for a convolution with the finite field of view of the instrument.

  1. ExtraSolar Planets Finding Extrasolar Planets. I

    E-print Network

    Walter, Frederick M.

    ExtraSolar Planets #12;Finding Extrasolar Planets. I Direct Searches Direct searches are difficult this? Yes, but it takes special techniques, and is not easy. #12;Finding Extrasolar Planets. II Most The three planets of Gl 876: masses = 2.5 MJ, 0.8 MJ, and 7.5 M #12;Gliese 876 #12;Finding Extrasolar

  2. THE COMPOSITIONAL DIVERSITY OF EXTRASOLAR TERRESTRIAL PLANETS. I. IN SITU SIMULATIONS

    SciTech Connect

    Bond, Jade C.; Lauretta, Dante S. [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); O'Brien, David P., E-mail: jbond@psi.ed [Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719 (United States)

    2010-06-01

    Extrasolar planet host stars have been found to be enriched in key planet-building elements. These enrichments have the potential to drastically alter the composition of material available for terrestrial planet formation. Here, we report on the combination of dynamical models of late-stage terrestrial planet formation within known extrasolar planetary systems with chemical equilibrium models of the composition of solid material within the disk. This allows us to determine the bulk elemental composition of simulated extrasolar terrestrial planets. A wide variety of resulting planetary compositions are found, ranging from those that are essentially 'Earth like', containing metallic Fe and Mg silicates, to those that are dominated by graphite and SiC. This shows that a diverse range of terrestrial planets may exist within extrasolar planetary systems.

  3. Observed properties of extrasolar planets.

    PubMed

    Howard, Andrew W

    2013-05-01

    Observational surveys for extrasolar planets probe the diverse outcomes of planet formation and evolution. These surveys measure the frequency of planets with different masses, sizes, orbital characteristics, and host star properties. Small planets between the sizes of Earth and Neptune substantially outnumber Jupiter-sized planets. The survey measurements support the core accretion model, in which planets form by the accumulation of solids and then gas in protoplanetary disks. The diversity of exoplanetary characteristics demonstrates that most of the gross features of the solar system are one outcome in a continuum of possibilities. The most common class of planetary system detectable today consists of one or more planets approximately one to three times Earth's size orbiting within a fraction of the Earth-Sun distance. PMID:23641110

  4. Transit of Extrasolar Planets

    NASA Technical Reports Server (NTRS)

    Doyle, Laurance R.

    1998-01-01

    During the past five years we have pursued the detection of extrasolar planets by the photometric transit method, i.e. the detection of a planet by watching for a drop in the brightness of the light as it crosses in front of a star. The planetary orbit must cross the line-of-sight and so most systems will not be lined up for such a transit to ever occur. However, we have looked at eclipsing binary systems which are already edge-on. Such systems must be very small in size as this makes the differential light change due to a transit much greater for a given planet size (the brightness difference will be proportional to the area of the transiting planet to the disc area of the star). Also, the planet forming region should be closer to the star as small stars are generally less luminous (that is, if the same thermal regime for planet formation applies as in the solar system). This led to studies of the habitable zone around other stars, as well. Finally, we discovered that our data could be used to detect giant planets without transits as we had been carefully timing the eclipses of the stars (using a GPS antenna for time) and this will drift by being offset by any giant planets orbiting around the system, as well. The best summary of our work may be to just summarize the 21 refereed papers produced during the time of this grant. This will be done is chronological order and in each section separately.

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

    E-print Network

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

    2014-01-01

    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 - epsilon 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 th...

  6. The Elemental Compositions of Extrasolar Minor Planets

    NASA Astrophysics Data System (ADS)

    Jura, Michael

    2013-10-01

    We propose to observe five white dwarfs known to be polluted by accretion of their own asteroids in order to investigate three related questions. {1} What determines carbon abundances within extrasolar asteroids? {2} Can we identify water-rich extrasolar planetesimals? {3} Can we find evidence for silicon-rich planetesimals, as would be expected if they are largely composed of crustal material? Data from these 5 proposed targets combined with previous COS observations either by ourselves or others of 6 additional targets, will complete an ultraviolet spectroscopic mini-survey of all known highly polluted white dwarfs with helium-dominated atmospheres within 80 pc of the Sun. This study will provide a unique legacy for understanding the formation and evolution of extrasolar rocky planets.

  7. The effect of tidal locking on the magnetospheric and atmospheric evolution of ``Hot Jupiters''

    Microsoft Academic Search

    J.-M. Grießmeier; A. Stadelmann; T. Penz; H. Lammer; F. Selsis; I. Ribas; E. F. Guinan; U. Motschmann; H. K. Biernat; W. W. Weiss

    2004-01-01

    We study the interaction between the planetary magnetosphere and atmosphere of the close-in extrasolar planets HD 209458b and OGLE-TR-56b with the stellar wind during the evolution of their host stars. Recent astrophysical observations of solar-like stars indicate that the radiation and particle environments of young stars are orders of magnitudes larger than for stars with ages comparable to the sun

  8. Clouds and Hazes in Exoplanet Atmospheres

    E-print Network

    Marley, Mark S; Cuzzi, Jeffrey N; Kitzmann, Daniel

    2013-01-01

    Clouds and hazes are commonplace in the atmospheres of solar system planets and are likely ubiquitous in the atmospheres of extrasolar planets as well. Clouds affect every aspect of a planetary atmosphere, from the transport of radiation, to atmospheric chemistry, to dynamics and they influence - if not control - aspects such as surface temperature and habitability. In this review we aim to provide an introduction to the role and properties of clouds in exoplanetary atmospheres. We consider the role clouds play in influencing the spectra of planets as well as their habitability and detectability. We briefly summarize how clouds are treated in terrestrial climate models and consider the far simpler approaches that have been taken so far to model exoplanet clouds, the evidence for which we also review. Since clouds play a major role in the atmospheres of certain classes of brown dwarfs we briefly discuss brown dwarf cloud modeling as well. We also review how the scattering and extinction efficiencies of cloud p...

  9. Models of Irradiated Extrasolar Giant Planets

    E-print Network

    Adam Burrows; David Sudarsky

    2002-07-23

    We review some of the characteristics of irradiated extrasolar giant planets (EGPs), in anticipation of their direct detection from the ground and from space. Spectral measurements are the key to unlocking their structural and atmospheric characteristics and to determining the true differences between giant planets and brown dwarfs. In this spirit, the theoretical spectral and atmospheric calculations we summarize here are in support of the many searches for EGPs to be conducted in the coming decade by astronomers from around the world.

  10. Atmospheric Biomarkers and their Evolution over Geological Timescales

    NASA Astrophysics Data System (ADS)

    Kaltenegger, Lisa; Jucks, K.; Traub, W.

    The search for life on extrasolar planets is based on the assumption that one can screen extrasolar planets for habitability spectroscopically. The first space born instruments able to detect as well as characterize extrasolar planets, Darwin and terrestrial planet finder (TPF-I and TPF-C) are scheduled to launch before the end of the next decade. The composition of the planetary surface, atmosphere, and its temperature-pressure profile influence a detectable spectroscopic signal considerably. For future space-based missions it will be crucial to know this influence to interpret the observed signals and detect signatures of life in remotely observed atmospheres. We give an overview of biomarkers in the visible and IR range, corresponding to the TPF-C and TPF-I/DARWIN concepts, respectively. We also give an overview of the evolution of biomarkers over time and its implication for the search for life on extrasolar Earth-like planets. We show that atmospheric features on Earth can provide clues of biological activities for at least 2 billion years.

  11. Atmospheric Biomarkers and their Evolution over Geological Timescales

    E-print Network

    L. Kaltenegger; K. Jucks; W. Traub

    2005-12-02

    The search for life on extrasolar planets is based on the assumption that one can screen extrasolar planets for habitability spectroscopically. The first space born instruments able to detect as well as characterize extrasolar planets, Darwin and terrestrial planet finder (TPF-I and TPF-C) are scheduled to launch before the end of the next decade. The composition of the planetary surface, atmosphere, and its temperature-pressure profile influence a detectable spectroscopic signal considerably. For future space-based missions it will be crucial to know this influence to interpret the observed signals and detect signatures of life in remotely observed atmospheres. We give an overview of biomarkers in the visible and IR range, corresponding to the TPF-C and TPF-I/DARWIN concepts, respectively. We also give an overview of the evolution of biomarkers over time and its implication for the search for life on extrasolar Earth-like planets. We show that atmospheric features on Earth can provide clues of biological activities for at least 2 billion years.

  12. Exploring the Potential of Integral Field Spectroscopy Observing Extrasolar Planet Transits: Ground Based Observations of the Atmospheric Na in HD209458b

    Microsoft Academic Search

    Santiago Arribas; Luis L ´ opez-Martin; Evencio Mediavilla; Pedro Gomez-Alvarez

    2005-01-01

    We explore the use of Integral Field Spectroscopy (IFS) to observe extrasolar\\u000aplanet transits. Although this technique should find its full potential in\\u000aspace observations (e.g. JWST, TPF), we have tested its basics with ground\\u000abased time series observations of HD209458b obtained with WHT+INTEGRAL during a\\u000atransit. For this analysis we used 5550 spectra, obtained in 150 exposures\\u000aduring a

  13. Schumann resonance: a tool to study planetary atmospheric electricity and the origin and evolution of the solar system

    NASA Astrophysics Data System (ADS)

    Hamelin, M.; Simoes, F. A.; Pfaff, R. F.; Béghin, C.; Berthelier, J.; Chamberlin, P. C.; Farrell, W. M.; Freudenreich, H.; Grard, R.; Klenzing, J.; Lebreton, J.; Martin, S.; Rowland, D. E.; Yair, Y.

    2012-12-01

    Investigation of extremely low frequency electromagnetic waves produced by lightning activity has been used to assist the characterization of a variety of phenomena related to atmospheric electricity in the Earth environment. Detection of Schumann Resonance spectral features of the earth-ionosphere cavity from outside the cavity offers new remote sensing capabilities to assess tropospheric-space weather connections, namely periodic patterns observed in a variety of tropospheric, ionospheric, and magnetospheric processes. A link between the water mixing ratio and atmospheric electrical conductivity makes Schumann resonance a suitable tool to assess volatile abundance of the outer planets, offering new capabilities to constrain thermodynamic parameters of the protosolar nebula from which the solar system evolved. In this work we discuss a technique and associated instrumentation to detect Schumann resonance signatures of planetary environments and subsequently to infer the fraction of volatiles and to investigate weather patterns in the gaseous envelopes of the giant planets.

  14. Extrasolar Trojan Planets close to Habitable Zones

    E-print Network

    R. Dvorak; E. Pilat-Lohinger; R. Schwarz; F. Freistetter

    2004-08-04

    We investigate the stability regions of hypothetical terrestrial planets around the Lagrangian equilibrium points L4 and L5 in some specific extrasolar planetary systems. The problem of their stability can be treated in the framework of the restricted three body problem where the host star and a massive Jupiter-like planet are the primary bodies and the terrestrial planet is regarded as being massless. From these theoretical investigations one cannot determine the extension of the stable zones around the equilibrium points. Using numerical experiments we determined their largeness for three test systems chosen from the table of the know extrasolar planets, where a giant planet is moving close to the so-called habitable zone around the host star in low eccentric orbits. The results show the dependence of the size and structure of this region, which shrinks significantly with the eccentricity of the known gas giant.

  15. Pressure Effects on Product Channels of Hydrocarbon Radical-Radical Reactions; Implications for Modelling of Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Fahr, A.; Halpern, J.; N'doumi, M.

    2011-10-01

    Previously we had studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modelling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2 and allyl, H2CCCH3) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. We have experimentally determined pressuredependent product yields for self- and cross-radical reactions performed at 298 K and at selected pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final products were determined by gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the observations and provided valuable information on complex reaction mechanisms. These studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report a compilation of our earlier results relevant to planetary atmospheres in addition to recent ones for allyl radical (H2CCCH3) reactions.

  16. The Astrometric Imaging Telescope - A space-based observatory for extra-solar planet detection

    NASA Technical Reports Server (NTRS)

    Pravdo, Steven H.

    1991-01-01

    The paper describes the objectives, techniques, instrumentation, and mission of the planned Astrometric Imaging Telescope. This space-based observatory is designed to detect and characterize extra-solar planetary systems. Results will contribute to the understanding of the astrophysics of stellar and planetary formation and provide an impetus for the study of exobiology.

  17. Planetary Population Synthesis Coupled with Atmospheric Escape: A Statistical View of Evaporation

    NASA Astrophysics Data System (ADS)

    Jin, Sheng; Mordasini, Christoph; Parmentier, Vivien; van Boekel, Roy; Henning, Thomas; Ji, Jianghui

    2014-11-01

    We apply hydrodynamic evaporation models to different synthetic planet populations that were obtained from a planet formation code based on the core-accretion paradigm. We investigated the evolution of the planet populations using several evaporation models, which are distinguished by the driving force of the escape flow (X-ray or EUV), the heating efficiency in energy-limited evaporation regimes, or both. Although the mass distribution of the planet populations is barely affected by evaporation, the radius distribution clearly shows a break at approximately 2 R ?. We find that evaporation can lead to a bimodal distribution of planetary sizes and to an "evaporation valley" running diagonally downward in the orbital distance—planetary radius plane, separating bare cores from low-mass planets that have kept some primordial H/He. Furthermore, this bimodal distribution is related to the initial characteristics of the planetary populations because low-mass planetary cores can only accrete small primordial H/He envelopes and their envelope masses are proportional to their core masses. We also find that the population-wide effect of evaporation is not sensitive to the heating efficiency of energy-limited description. However, in two extreme cases, namely without evaporation or with a 100% heating efficiency in an evaporation model, the final size distributions show significant differences; these two scenarios can be ruled out from the size distribution of Kepler candidates.

  18. Electrodynamics in Giant Planet Atmospheres

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The atmospheres of close-in extrasolar giant planets such as HD209458b are strongly ionized by the UV flux of their host stars. We show that photoionization on such planets creates a dayside ionosphere that extends from the thermosphere to the 100 mbar level. The resulting peak electron density near the 1 mbar level is higher than that encountered in any planetary ionosphere of the solar system, and the model conductivity is in fact comparable to the atmospheres of Sun-like stars. As a result, the momentum and energy balance in the upper atmosphere of HD209458b and similar planets can be strongly affected by ion drag and resistive heating arising from wind-driven electrodynamics. Despite much weaker ionization, electrodynamics is nevertheless also important on the giant planets of the solar system. We use a generic framework to constrain the conductivity regimes on close-in extrasolar planets, and compare the results with conductivites based on the same approach for Jupiter and Saturn. By using a generalized Ohm's law and assumed magnetic fields, we then demonstrate the basic effects of wind-driven ion drag in giant planet atmospheres. Our results show that ion drag is often significant in the upper atmosphere where it can also substantially alter the energy budget through resistive heating.

  19. Planetary astronomy

    NASA Technical Reports Server (NTRS)

    Morrison, David; Hunten, Donald; Ahearn, Michael F.; Belton, Michael J. S.; Black, David; Brown, Robert A.; Brown, Robert Hamilton; Cochran, Anita L.; Cruikshank, Dale P.; Depater, Imke

    1991-01-01

    The authors profile the field of astronomy, identify some of the key scientific questions that can be addressed during the decade of the 1990's, and recommend several facilities that are critically important for answering these questions. Scientific opportunities for the 1990' are discussed. Areas discussed include protoplanetary disks, an inventory of the solar system, primitive material in the solar system, the dynamics of planetary atmospheres, planetary rings and ring dynamics, the composition and structure of the atmospheres of giant planets, the volcanoes of IO, and the mineralogy of the Martian surface. Critical technology developments, proposed projects and facilities, and recommendations for research and facilities are discussed.

  20. Witnessing Extrasolar Asteroid Destruction?

    NASA Astrophysics Data System (ADS)

    Xu, Siyi; Jura, Michael; Su, Kate; Meng, Huan

    2014-11-01

    40 white dwarfs with excess infrared radiation due to a circumstellar dust disk from tidally disrupted asteroids have been identified. Recently, we identified one dusty white dwarf whose infrared fluxes have been increasing since May 2014. Very likely, it is caused by a recent tidal disruption event of extrasolar asteroid. We propose DDT to follow it up in a timely manner because the flare could dissipate very soon. This proposal provides a unique opportunity to study the destruction of an extrasolar asteroid.

  1. Direct Imaging of Warm Extrasolar Planets

    SciTech Connect

    Macintosh, B

    2005-04-11

    One of the most exciting scientific discoveries in the last decade of the twentieth century was the first detection of planets orbiting a star other than our own. By now more than 130 extrasolar planets have been discovered indirectly, by observing the gravitational effects of the planet on the radial velocity of its parent star. This technique has fundamental limitations: it is most sensitive to planets close to their star, and it determines only a planet's orbital period and a lower limit on the planet's mass. As a result, all the planetary systems found so far are very different from our own--they have giant Jupiter-sized planets orbiting close to their star, where the terrestrial planets are found in our solar system. Such systems have overturned the conventional paradigm of planet formation, but have no room in them for habitable Earth-like planets. A powerful complement to radial velocity detections of extrasolar planets will be direct imaging--seeing photons from the planet itself. Such a detection would allow photometric measurements to determine the temperature and radius of a planet. Also, direct detection is most sensitive to planets in wide orbits, and hence more capable of seeing solar systems resembling our own, since a giant planet in a wide orbit does not preclude the presence of an Earth-like planet closer to the star. Direct detection, however, is extremely challenging. Jupiter is roughly a billion times fainter than our sun. Two techniques allowed us to overcome this formidable contrast and attempt to see giant planets directly. The first is adaptive optics (AO) which allows giant earth-based telescopes, such as the 10 meter W.M. Keck telescope, to partially overcome the blurring effects of atmospheric turbulence. The second is looking for young planets: by searching in the infrared for companions to young stars, we can see thermal emission from planets that are still warm with the heat of their formation. Together with a UCLA team that leads the field of young-star identification, we carried out a systematic near-infrared search for young planetary companions to {approx}200 young stars. We also carried out targeted high-sensitivity observations of selected stars surrounded by circumstellar dust rings. We developed advanced image processing techniques to allow detection of even fainter sources buried in the noisy halo of scattered starlight. Even with these techniques, around most of our targets our search was only sensitive to planets in orbits significantly wider than our solar system. With some carefully selected targets--very young dusty stars in the solar neighborhood--we reach sensitivities sufficient to see solar systems like our own. Although we discovered no unambiguous planets, we can significantly constrain the frequency of such planets in wide (>50 AU) orbits, which helps determine which models of planet formation remain plausible. Successful modeling of our observations has led us to the design of a next-generation AO system that will truly be capable of exploring solar systems resembling our own.

  2. Upsilon Andromedae: A Rosetta Stone in Planetary Dynamics

    E-print Network

    E. I. Chiang

    2002-10-18

    We review the orbital dynamics exhibited by the first extra-solar planetary system discovered, Upsilon Andromedae. This system is unique in combining all of the surprising architectural features displayed individually by extrasolar planetary systems found today: (1) a hot Jupiter, (2) two planets on highly eccentric orbits, and (3) a stellar companion. We discuss the system's stability properties and its possible origin. Planet-disk interactions seem critical to the emerging story.

  3. Upsilon Andromedae A Rosetta Stone in Planetary Dynamics

    E-print Network

    Chiang, E I

    2002-01-01

    We review the orbital dynamics exhibited by the first extra-solar planetary system discovered, Upsilon Andromedae. This system is unique in combining all of the surprising architectural features displayed individually by extrasolar planetary systems found today: (1) a hot Jupiter, (2) two planets on highly eccentric orbits, and (3) a stellar companion. We discuss the system's stability properties and its possible origin. Planet-disk interactions seem critical to the emerging story.

  4. HAT-P-15b: A 10.9 DAY EXTRASOLAR PLANET TRANSITING A SOLAR-TYPE STAR

    SciTech Connect

    Kovacs, G. [Konkoly Observatory, Budapest (Hungary); Bakos, G. A.; Hartman, J. D.; Torres, G.; Noyes, R. W.; Latham, D. W.; Sasselov, D. D.; Stefanik, R. P.; Esquerdo, G. A.; Fernandez, J. M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Howard, A. W.; Marcy, G. W.; Isaacson, H. [Department of Astronomy, University of California, Berkeley, CA (United States); Fischer, D. A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Johnson, J. A. [California Institute of Technology, Department of Astrophysics, MC 249-17, Pasadena, CA (United States); Lazar, B. Beky J.; Papp, I.; Sari, P., E-mail: gbakos@cfa.harvard.ed [Hungarian Astronomical Association, Budapest (Hungary)

    2010-12-01

    We report the discovery of HAT-P-15b, a transiting extrasolar planet in the 'period valley', a relatively sparsely populated period regime of the known extrasolar planets. The host star, GSC 2883-01687, is a G5 dwarf with V= 12.16. It has a mass of 1.01 {+-} 0.04 M{sub sun}, radius of 1.08 {+-} 0.04 R{sub sun}, effective temperature 5568 {+-} 90 K, and metallicity [Fe/H] = +0.22 {+-} 0.08. The planetary companion orbits the star with a period P = 10.863502 {+-} 0.000027 days, transit epoch T{sub c} = 2454638.56019 {+-} 0.00048 (BJD), and transit duration 0.2285 {+-} 0.0015 days. It has a mass of 1.946 {+-} 0.066 M{sub J} and radius of 1.072 {+-} 0.043 R{sub J} yielding a mean density of 1.96 {+-} 0.22 g cm{sup -3}. At an age of 6.8{sup +2.5}{sub -1.6} Gyr, the planet is H/He-dominated and theoretical models require about 2% (10 M{sub +}) worth of heavy elements to reproduce its measured radius. With an estimated equilibrium temperature of {approx}820 K during transit, and {approx}1000 K at occultation, HAT-P-15b is a potential candidate to study moderately cool planetary atmospheres by transmission and occultation spectroscopy.

  5. Refraction in planetary atmospheres: improved analytical expressions and comparison with a new ray-tracing algorithm

    E-print Network

    Betremieux, Yan

    2015-01-01

    Atmospheric refraction affects to various degrees exoplanet transit, lunar eclipse, as well as stellar occultation observations. Exoplanet retrieval algorithms often use analytical expressions for the column abundance along a ray traversing the atmosphere as well as for the deflection of that ray, which are first order approximations valid for low densities in a spherically symmetric homogeneous isothermal atmosphere. We derive new analytical formulae for both of these quantities, which are valid for higher densities, and use them to refine and validate a new ray tracing algorithm which can be used for arbitrary atmospheric temperature-pressure profiles. We illustrate with simple isothermal atmospheric profiles the consequences of our model for different planets: temperate Earth-like and Jovian-like planets, as well as HD189733b, and GJ1214b. We find that, for both hot exoplanets, our treatment of refraction does not make much of a difference to pressures as high as 10 atmosphere, but that it is important to ...

  6. Laboratory evaluation of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, P. G.

    1984-01-01

    The microwave absorbing properties of gaseous sulfuric acid (H2SO4) under Venus atmospheric conditions are investigated. The results are applied to measurements from Mariner 5, Mariner 10, and Pioneer/Venus Radio Occultation experiments, to determine abundancies of gaseous sulfuric acid in the Venus atmosphere. The microwave properties of the vapors accompanying liquid H2SO4 are studied to estimate the vapor pressure in an atmospheric model.

  7. * Corresponding author. Present address: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Fax: #617-253-4464.

    E-print Network

    Khatiwala, Samar

    * Corresponding author. Present address: Department of Earth, Atmospheric and Planetary Sciences@ocean.mit.edu (S. Khatiwala). Deep-Sea Research I 48 (2001) 1423}1441 Age tracers in an ocean GCM S. Khatiwala*, M. Visbeck, P. Schlosser Lamont}Doherty Earth Observatory and Department of Earth and Environmental Sciences

  8. Lithium chemistry in brown dwarfs and extrasolar gas giant planets

    NASA Astrophysics Data System (ADS)

    Lodders, K.

    1998-09-01

    Lithium chemistry (and that of all other naturally occurring elements) in brown dwarfs and gas giant planet atmospheres is being investigated by thermochemical equilibrium calculations, using the CONDOR code (Fegley and Lodders, 1994, Icarus 110, 117). The calculations are done for solar composition material over a wide pressure (P) and temperature (T) range appropriate for model atmospheres of Gl 229B, other brown dwarfs and putative extrasolar gas giant planets. Monatomic Li is the major Li gas at high T (but below the Li-Li+ boundary). As T decreases, Li (g) reacts to form LiCl. The abundances of LiH and LiOH also increase with decreasing T, but they are always less important than LiCl. The Li-LiCl boundary (equal abundance of these two gases) is given by the equation: 10,000/T ~ 6.565-0.3574 log P (bar). Between the Li-LiCl boundary and the Li_2S condensation line, which removes all Li from the gas at even lower T, monatomic Li is still present but at lower abundances than LiCl. The presence or absence of detectable monatomic Li in cool, low-mass objects is often used as a discriminant of whether or not the object has reached the stellar mass limit of 0.07-0.08 solar masses (Li absent) or has a lower substellar mass (Li present). However, this work shows that the Li-test for brown dwarf candidates suggested by Rebollo and coworkers (1992, ApJ. 389, L83) may only apply to objects with sufficiently hot atmospheres, where Li is dominantly in its monatomic form. In the coolest brown dwarfs and in gas giant planets low atomic Li abundances or the absence of Li occurs because Li forms LiCl gas or condenses out as Li_2S. Supported by NAG5-6366 from the NASA Planetary Atmospheres Program.

  9. CARBON-RICH MOLECULAR CHAINS IN PROTOPLANETARY AND PLANETARY ATMOSPHERES: QUANTUM MECHANISMS AND ELECTRON ATTACHMENT RATES FOR ANION FORMATION

    SciTech Connect

    Carelli, F.; Grassi, T.; Gianturco, F. A. [Department of Chemistry and CNISM, University of Rome ''Sapienza'', Piazzale Aldo Moro 5, 00185 Rome (Italy); Satta, M., E-mail: francesco.gianturco@uniroma1.it [CNR-ISMN and University of Rome ''Sapienza'', Piazzale Aldo Moro 5, 00185 Rome (Italy)

    2013-09-10

    The elementary mechanisms through which molecular polyynes could form stable negative ions after interacting with free electrons in planetary atmospheres (e.g., Titan's) are analyzed using quantum scattering calculations and quantum structure methods. The case of radical species and of nonpolar partners are analyzed via specific examples for both the C{sub n}H and HC{sub n}H series, with n values from 4 to 12. We show that attachment processes to polar radicals are dominating the anionic production and that the mediating role of dipolar scattering states is crucial to their formation. The corresponding attachment rates are presented as calculated upper limits to their likely values and are obtained down to the low temperatures of interest. The effects of the computed rates, when used in simple evolutionary models, are also investigated and presented in detail.

  10. Characterization of Complex Organic Compounds Formed in Simulated Planetary Atmospheres by the Action of High Energy Particles

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kensei; Kaneko, Takeo; Saito, Takeshi

    1999-01-01

    A wide variety of organic compounds, which are not simple organics but also complex organics, have been found in planets and comets. We reported that complex organics was formed in simulated planetary atmospheres by the action of high energy particles. Here we characterized the experimental products by using chromatographic and mass spectrometric techniques. A gaseous mixture of CO, N2 and H2O was irradiated with high energy protons (major components of cosmic rays). Water-soluble non-volatile substances, which gave amino acids after acid-hydrolysis, were characterized by HPLC and mass spectrometry. Major part of the products were complex compounds with molecular weight of several hundreds. Amino acid precursors were produced even when no water was incorporated with the starting materials. It was suggested that complex molecules including amino acid precursors were formed not in solution from simple molecules like HCN, but directly in gaseous phase

  11. The Bistatic Radar-Occultation Method for the Study of Planetary Atmospheres

    Microsoft Academic Search

    G. Fjeldbo; V. R. Eshleman

    1965-01-01

    Theoretical studies have been made of the characteristics of radio waves dif- fracted at the limb and refracted in the atmosphere of a planet. Sample computations have been made of atmospheric perturbations to the communication links to and from a Mars flyby spacecraft having a trajectory that involves occultation of the spacecraft by the planet as seen from the earth.

  12. THE COMPOSITIONAL DIVERSITY OF EXTRASOLAR TERRESTRIAL PLANETS. II. MIGRATION SIMULATIONS

    SciTech Connect

    Carter-Bond, Jade C. [School of Physics, University of New South Wales, Kensington, NSW 2052 (Australia); O'Brien, David P. [Planetary Science Institute, 1700 East Fort Lowell, Tucson, AZ 85719 (United States); Raymond, Sean N., E-mail: j.bond@unsw.edu.au [Observatoire Aquitain des Sciences de l'Univers, Universite de Bordeaux, 2 rue de l'Observatoire, BP 89, F-33271 Floirac Cedex (France)

    2012-11-20

    Prior work has found that a variety of terrestrial planetary compositions are expected to occur within known extrasolar planetary systems. However, such studies ignored the effects of giant planet migration, which is thought to be very common in extrasolar systems. Here we present calculations of the compositions of terrestrial planets that formed in dynamical simulations incorporating varying degrees of giant planet migration. We used chemical equilibrium models of the solid material present in the disks of five known planetary host stars: the Sun, GJ 777, HD4203, HD19994, and HD213240. Giant planet migration has a strong effect on the compositions of simulated terrestrial planets as the migration results in large-scale mixing between terrestrial planet building blocks that condensed at a range of temperatures. This mixing acts to (1) increase the typical abundance of Mg-rich silicates in the terrestrial planets' feeding zones and thus increase the frequency of planets with Earth-like compositions compared with simulations with static giant planet orbits, and (2) drastically increase the efficiency of the delivery of hydrous phases (water and serpentine) to terrestrial planets and thus produce waterworlds and/or wet Earths. Our results demonstrate that although a wide variety of terrestrial planet compositions can still be produced, planets with Earth-like compositions should be common within extrasolar planetary systems.

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

    Microsoft Academic Search

    Manfred Cuntz; Steven H. Saar; Zdzislaw E. Musielak

    2000-01-01

    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

  14. Tm:germanate Fiber Laser for Planetary Water Vapor Atmospheric Profiling

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; De Young, Russell

    2009-01-01

    The atmospheric profiling of water vapor is necessary for finding life on Mars and weather on Earth. The design and performance of a water vapor lidar based on a Tm:germanate fiber laser is presented.

  15. A Grant from NASA's Office of Space Station Science, Planetary Atmosphere's Program to Boston University

    NASA Technical Reports Server (NTRS)

    Yelle, Roger V.

    2000-01-01

    In the past three years of this program we have made contributions to a variety of subjects in research on Jupiter's Atmosphere, the Ultraviolet Spectroscopy of Jupiter, the abundance of CH4 in Pluto's atmosphere, and the emissivity of Pluto's Surface. We also performed work on two projects related to Titan, and an analysis of the visible spectrum of a brown dwarf. The highpoints are briefly summarized and a list of papers supported partly or wholly by this program is also provided.

  16. The Extrasolar Planets Encyclopaedia

    NSDL National Science Digital Library

    Jean Schneider, of the Observatoire de Paris, put together this no-nonsense site featuring current information on the "detection and study of extrasolar planets, including exobiology." Schneider's commitment to the subject is clear with the inclusion of detailed scientific and technical articles, a tutorial (by Arizona State University) on the detection of extrasolar planets, and a hyperlinked bibliography of some 200 scientific journal articles, books, and reports. A catalog of extrasolar planets (with links to the scientific articles describing them) features dozens of confirmed planets (or brown dwarfs) around main sequence stars or pulsars, in addition to disks and unconfirmed objects. Whether you are a dedicated amateur or pro (and read English or French), these pages are clearly designed and well worth the orbit.

  17. Signs of Planetary Microlensing Signals

    E-print Network

    Cheongho Han; Kyongae Chang

    2003-07-21

    An extrasolar planet can be detected via microlensing from the perturbation it makes in the smooth lensing light curve of the primary. In addition to the conventional photometric microlensing, astrometric observation of the center-of-light motion of the source star image provides a new channel of detecting and characterizing extrasolar planets. It was known that the planet-induced astrometric signals tend to be positive while the photometric signals can be either positive or negative. In this paper, we analytically show the reason for these tendencies of microlensing planetary signals.

  18. Exploring the Potential of Integral Field Spectroscopy Observing Extrasolar Planet Transits: Ground Based Observations of the Atmospheric Na in HD209458b

    E-print Network

    Santiago Arribas; Ronald L. Gilliland; William B. Sparks; Luis Lopez-Martin; Evencio Mediavilla; Pedro Gomez-Alvarez; .

    2005-09-14

    We explore the use of Integral Field Spectroscopy (IFS) to observe extrasolar planet transits. Although this technique should find its full potential in space observations (e.g. JWST, TPF), we have tested its basics with ground based time series observations of HD209458b obtained with WHT+INTEGRAL during a transit. For this analysis we used 5550 spectra, obtained in 150 exposures during a period of >7 hours. We found that IFS offers 3 fundamental advantages with respect to previously used methods. (i) It improves the effective S/N in photon limited observations by distributing the light coming from the star into the 2 dimensions of the detector. (ii) This type of IFS data allows to 'auto-calibrate' instrumental and background effects. (iii) Since the star image characteristics as well as its photometric properties are extracted from the same data-cube, it is possible to decorrelate photometric instabilities induced by PSF variations. These data have also allowed us to explore the accuracy limits of ground based 'relative' spectrophotometry. This was done using a photometric index that probes the NaD lines, for which we obtained a nominal 1-sigma error of ~1.0x10^-4. This result, based on observations of only 1 transit, indicates that this type of ground observation can constrain the characterization of the transmission spectrum of extrasolar planets. The present observations are compatible with no extra NaD depression during the transit. Though this result seems to be inconsistent with the recently reported HST-STIS findings we point out its limited statistical meaning: the results disagree within 1-sigma, but agree within 2-sigma. We also give some recommenda-tions to instrument developers in order to enhance the efficiency of the method.

  19. Phase transition to super-rotating atmospheres in a simple planetary model for a nonrotating massive planet: Exact solution

    NASA Astrophysics Data System (ADS)

    Lim, Chjan C.

    2012-12-01

    An energy-enstrophy model for the equilibrium statistical mechanics of barotropic flow on a massive nonrotating sphere is introduced and solved exactly for phase transitions to rotating solid-body atmospheres when the kinetic energy level is high. Unlike the Kraichnan theory which is a Gaussian model, we substitute a microcanonical enstrophy constraint for the usual canonical one, a step which is based on sound physical principles. This yields a spherical model with zero total circulation, microcanonical enstrophy constraint, and canonical constraint on energy, leaving angular momentum free as is required for any model whose objective is to predict super-rotation in planetary atmospheres. A closed-form solution of this spherical model, obtained by the Kac-Berlin method of steepest descent, provides critical temperatures and amplitudes of the symmetry-breaking rotating solid-body flows. The critical values depend linearly on the relative enstrophy, with proportionality constant derived from the spectrum of the Laplace-Beltrami operator on the sphere, as expected within an energy-enstrophy theory for macroscopic turbulent flows. This model and its results differ from previous solvable models for related phenomena in the sense that the model is not based on a mean-field assumption.

  20. Spectral properties of condensed phases of disulfur monoxide, polysulfur oxide, and irradiated sulfur. [In planetary atmospheres

    SciTech Connect

    Hapke, B.; Graham, F. (Pittsburgh Univ., PA (USA))

    1989-05-01

    The spectral reflectances of S2O, as well as the polysulfur oxide (PSO) condensate dissociation products of SO2 and condensates of elemental sulfur irradiated with UV light and X-rays, have been ascertained in the 200-1700 nm range with a view to the relevance of these compounds to the interpretation of planetary data. While S2O is a dark red solid, PSO is a pale yellow one that absorbs strongly in the UV but exhibits no bands in either the visible or near IR. Elemental S produces strong bands in the UV, and while it is normally white at room temperature, UV irradiation causes it to turn yellow. X-ray irradiation of S turns it orange. 24 refs.

  1. Spectral properties of condensed phases of disulfur monoxide, polysulfur oxide, and irradiated sulfur. [in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hapke, Bruce; Graham, Francis

    1989-01-01

    The spectral reflectances of S2O, as well as the polysulfur oxide (PSO) condensate dissociation products of SO2 and condensates of elemental sulfur irradiated with UV light and X-rays, have been ascertained in the 200-1700 nm range with a view to the relevance of these compounds to the interpretation of planetary data. While S2O is a dark red solid, PSO is a pale yellow one that absorbs strongly in the UV but exhibits no bands in either the visible or near IR. Elemental S produces strong bands in the UV, and while it is normally white at room temperature, UV irradiation causes it to turn yellow. X-ray irradiation of S turns it orange.

  2. High resolution infrared spectroscopy: Some new approaches and applications to planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Mumma, M. J.

    1978-01-01

    The principles of spectral line formation and of techniques for retrieval of atmospheric temperature and constituent profiles are discussed. Applications to the atmospheres of Earth, Mars, Venus, and Jupiter are illustrated by results obtained with Fourier transform and infrared heterodyne spectrometers at resolving powers (lambda/delta hyperon lambda of approximately 10,000 and approximately 10 to the seventh power), respectively, showing the high complementarity of spectroscopy at these two widely different resolving powers. The principles of heterodyne spectroscopy are presented and its applications to atmospheric probing and to laboratory spectroscopy are discussed. Direct absorption spectroscopy with tuneable semiconductor lasers is discussed in terms of precision frequency-and line strength-measurements, showing substantial advances in laboratory infrared spectroscopy.

  3. Pervasive orbital eccentricities dictate the habitability of extrasolar earths.

    PubMed

    Kita, Ryosuke; Rasio, Frederic; Takeda, Genya

    2010-09-01

    The long-term habitability of Earth-like planets requires low orbital eccentricities. A secular perturbation from a distant stellar companion is a very important mechanism in exciting planetary eccentricities, as many of the extrasolar planetary systems are associated with stellar companions. Although the orbital evolution of an Earth-like planet in a stellar binary system is well understood, the effect of a binary perturbation on a more realistic system containing additional gas-giant planets has been very little studied. Here, we provide analytic criteria confirmed by a large ensemble of numerical integrations that identify the initial orbital parameters leading to eccentric orbits. We show that an extrasolar earth is likely to experience a broad range of orbital evolution dictated by the location of a gas-giant planet, which necessitates more focused studies on the effect of eccentricity on the potential for life. PMID:20879864

  4. A Hybrid Method for Modeling Polarized Radiative Transfer in a Spherical-shell Planetary Atmosphere

    NASA Astrophysics Data System (ADS)

    Xu, F.; West, R. A.; Davis, A. B.

    2012-12-01

    The Markov chain method is formulated for polarized radiative transfer in a pseudo-spherical atmosphere. It is used as an initial guess of the solution to a full spherical-shell atmosphere. By use of the short characteristic method, a convergent radiant field throughout the atmosphere is achieved after a few Picard iterations. This hybrid method was validated by comparing the numerical results to those obtained by a backward Monte Carlo method. Demonstration calculations were then performed to simulate images of Titan's haze in reflectance intensity (I) and in polarization (including Q and U, degree of polarization, and angle of polarization) at the wavelength 934.8 nm. Comparison of the measured I and Q images by Imaging Science Subsystem (ISS) instrument on the Cassini spacecraft to those modeled by our method shows that hybrid method has great potential for radiative transfer analysis for a thick (both physically and optically) spherical-shell atmospheres (see Figs.1-2 as an example of comparison of measured and modeled Q/F for Titan haze). Fig. 1 Titan haze: Measured Q/F by ISS Camera from Day of Year 309 of 2008. The white circle marks the edge of Titan plate Fig. 2 Titan haze: Modeled Q/F.

  5. Work output of planetary atmospheric engines: dissipation in clouds and rain

    E-print Network

    Lorenz, Ralph D.

    of clouds ``floating'' in air, each and every cloud droplet is pulled towards the ground by gravity as the original function of steam engines was to lift water, a principal output of the atmospheric heat engine is to raise water vertically. [3] In this paper, we discuss the dissipation of the work output of the climate

  6. The Martian atmospheric planetary boundary layer stability, fluxes, spectra, and similarity

    Microsoft Academic Search

    James E. Tillman

    1994-01-01

    This is the first analysis of the high frequency data from the Viking lander and spectra of wind, in the Martian atmospheric surface layer, along with the diurnal variation of the height of the mixed surface layer, are calculated for the first time for Mars. Heat and momentum fluxes, stability, and zO are estimated for early spring, from a surface

  7. Stellar wind regimes of close-in extrasolar planets

    Microsoft Academic Search

    S. Preusse; A. Kopp; J. Büchner; U. Motschmann

    2005-01-01

    Close-in extrasolar planets of Sun-like stars are exposed to stellar wind conditions that differ considerably from those for planets in the solar system. Unfortunately, these stellar winds belong to the still unknown parameters of these planetary systems. On the other hand, they play a crucial role in a number of star-planet interaction processes that may lead to observable radiation events.

  8. Low-temperature Kinetic Studies of OH Radical Reactions Relevant to Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Townsend, T. M.; Antiñolo, M.; Ballesteros, B.; Jimenez, E.; Canosa, A.

    2011-05-01

    In the solar system, the temperature (T) of the atmosphere of giant planets or their satellites is only several tens of Kelvin (K). The temperature of the tropopause of Titan (satellite of Saturn) and the surface of Mars is 70 K and 210 K, respectively. In the Earth's atmosphere, T decreases from 298 K (surface) to 210 K close to the T-inversion region (tropopause). The principal oxidants in the Earth's lower atmosphere are ozone, the hydroxyl (OH) radical and hydrogen peroxide. A number of critical atmospheric chemical problems depend on the Earth's oxidising capacity, which is essentially the global burden of these oxidants. In the interstellar clouds and circumstellar envelopes, OH radicals have also been detected. As the chemistry of atmospheres is highly influenced by temperature, the knowledge of the T-dependence of the rate coefficients for OH-reactions (k) is the key to understanding the underlying molecular mechanisms. In general, these reactions take place on a short temporal scale. Therefore, a detection technique with high temporal resolution is required. Measurements of k at low temperatures can be achieved by maintaining a thermalised environment using either cryogenic cooling (T>200 K) or supersonic gas expansion with a Laval nozzle (several tens of K). The pulsed laser photolysis technique coupled with laser induced fluorescence detection has been widely used in our laboratory to determine the rate coefficients of OH-reactions with different volatile organic compounds, such as alcohols (1), saturated and unsaturated aliphatic aldehydes (2), linear ketones (3), as a function of temperature (260 350 K). An experimental system based on the CRESU (Cinetique de Reaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique is currently under construction. This technique will allow the performance of kinetic studies of OH-reactions of astrophysical interest at temperatures lower than 200 K.

  9. The Search for the Extrasolar Planets: A Brief History of the Search, the Findings and the Future Implications

    NSDL National Science Digital Library

    Bell, George

    This website, authored by George Bell of Arizona State University, gives an extensive outline of the history and results of the discovery of extrasolar planets. Topics include planetary like objects, orbiting pulsars and recent work being done by scientists detecting extra solar planetary systems and objects. External references for further research are included.

  10. Extrasolar Planet Inferometric Survey (EPIcS)

    NASA Technical Reports Server (NTRS)

    Shao, Michael; Baliunas, Sallie; Boden, Andrew; Kulkarni, Shrinivas; Lin, Douglas N. C.; Loredo, Tom; Queloz, Didier; Shaklan, Stuart; Tremaine, Scott; Wolszczan, Alexander

    2004-01-01

    The discovery of the nature of the solar system was a crowning achievement of Renaissance science. The quest to evaluate the properties of extrasolar planetary systems is central to both the intellectual understanding of our origins and the cultural understanding of humanity's place in the Universe; thus it is appropriate that the goals and objectives of NASA's breakthrough Origins program emphasize the study of planetary systems, with a focus on the search for habitable planets. We propose an ambitious research program that will use SIM - the first major mission of the Origins program - to explore planetary systems in our Galactic neighborhood. Our program is a novel two-tiered SIM survey of nearby stars that exploits the capabilities of SIM to achieve two scientific objectives: (i) to identify Earth-like planets in habitable regions around nearby Sunlike stars: and (ii) to explore the nature and evolution of planetary systems in their full variety. The first of these objectives was recently recommended by the Astronomy and Astrophysics Survey Committee (the McKee-Taylor Committee) as a prerequisite for the development of the Terrestrial Planet Finder mission later in the decade. Our program combines this two-part survey with preparatory and contemporaneous research designed to maximize the scientific return from the limited and thus precious observing resources of SIM.

  11. Perturbative approach to the astrometric microlensing due to an extrasolar planet

    E-print Network

    Hideki Asada

    2002-03-25

    We have developed a perturbative approach to microlensing due to an extrasolar planetary lens. In particular, we have found analytic formulae for triple images. We have used the formulae to investigate the astrometric microlensing due to the extrasolar planetary lens, in expectation of dramatic improvements in the precision of the future astrometric measurements. For a weak lensing case, we have shown how the maximum angular size and the typical time scale of the anomalous shift of the lightcentroid are dependent on the mass ratio and angular separation between the star and the planet.

  12. Impact of variations of gravitational acceleration on the general circulation of the planetary atmosphere

    NASA Astrophysics Data System (ADS)

    Kilic, Cevahir; Raible, Christoph C.; Stocker, Thomas F.

    2015-04-01

    Instrumentation to detect new planets has been continually developed over the last decades. Thus, exoplanets can be characterised in terms of physical parameters, such as size and mass, as well as identify possible atmospheres. The increasing number of newly detected planets raises issues of possible other habitable worlds. In this study, the atmospheric dynamics of potential habitable planets is investigated using a three-dimensional atmospheric general circulation model (Planet Simulator) of intermediate complexity (Lunkeit et al. 2011). A set of sensitivity simulations varying the gravitational acceleration from 1/4g0 to 5g0 (with g0 = 9.81ms-2) are performed in an aquaplanet configuration. Except of that all simulations are performed with Earth-like initial conditions, which reach after 4 to 10 years a steady-state. The gravitation of a terrestrial planet significantly influences atmospheric dynamics. Up to 1g0, the meridional atmospheric circulation is driven by a three-cell structure on one hemisphere: a thermally direct cell between 0°and ±30°(Hadley cell), a thermally indirect cell between ±30°and ±60°(Ferrel cell) and a third cell (polar cell), which is also a thermally direct cell. Further, all cells illustrated by the mass stream function become more intense with increasing gravity from 1/4g0 to 1g0. However, for experiments greater than 1g0 the general atmospheric circulation begins to change fundamentally. The thermally indirect cell becomes weaker and vanishes completely with 3g0, whereas both direct thermal cells enhance and merge around 3g0. Hence, one strong thermally direct cell remains, which becomes stronger with increasing gravity acceleration (> 3g0). To understand the physical processes leading to a one-cell structure, the main drivers are considered separately: diabatic heating, meridional eddy fluxes of heat and momentum, and zonal shear. The results show that all main processes enhance with increasing gravity up to 1g0. For g > g0, both eddy processes, heat and momentum flux, become weaker, whereas the contribution of diabatic heating and zonal shear still increase. The increase of zonal shear is explained by a denser air due to increased gravity. The increase of the diabatic heating caused by an increasing Brunt-Väisälä frequency and the weakening of the eddy processes at the same time lead to a direct thermally driven circulation from the equator to the poles, i.e., a one-cell structure on each hemisphere. References Lunkeit, F., et al., Planet Simulator - Reference Manual Version 16, Meteorological Institute, University of Hamburg, 2011.

  13. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1991-01-01

    Laboratory measurements of microwave and millimeter wave properties of the simulated atmosphere of the outer planets and their satellites has continued. One of the focuses is on the development of a radiative transfer model of the Jovian atmosphere at wavelengths from 1 mm to 10 cm. This modeling effort led to laboratory measurements of the millimeter wave opacity of hydrogen sulfide (H2S) under simulated Jovian conditions. Descriptions of the modeling effort, the Laboratory experiment, and the observations are presented. Correlative studies of measurements with Pioneer-Venus radio occultation measurements with longer wavelength emission measurements have provided new ways for characterizing temporal and spatial variations in the abundance of both gases H2SO4 and SO2, and for modeling their roles in the subcloud atmosphere. Laboratory measurements were conducted on 1.35 cm (and 13 cm) opacity of gaseous SO2 and absorptivity of gaseous SO2 at the 3.2 mm wavelength under simulated Venus conditions. Laboratory measurements were completed on millimeter wave dielectric properties of liquid H2SO4, in order to model the effects of the opacity of the clouds of Venus onto millimeter wave emission spectrum.

  14. Planet Formation and the Characteristics of Extrasolar Planets

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    An overview of current theories of planetary growth, emphasizing the formation of extrasolar planets, is presented. Models of planet formation are based upon observations of the Solar System, extrasolar planets, and young stars and their environments. 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 if they become massive enough before the protoplanetary disk dissipates, then they are able to accumulate substantial amounts of gas. These models predict that rocky planets should form in orbit about most single 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. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. The implications of the giant planets found in recent radial velocity searches for the abundances of habitable planets are discussed.

  15. Atomic carbon emission from photodissociation of CO2. [planetary atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Wu, C. Y. R.; Phillips, E.; Lee, L. C.; Judge, D. L.

    1978-01-01

    Atomic carbon fluorescence, C I 1561, 1657, and 1931 A, has been observed from photodissociation of CO2, and the production cross sections have been measured. A line emission source provided the primary photons at wavelengths from threshold to 420 A. The present results suggest that the excited carbon atoms are produced by total dissociation of CO2 into three atoms. The cross sections for producing the O I 1304-A fluorescence through photodissociation of CO2 are found to be less than 0.01 Mb in the wavelength region from 420 to 835 A. The present data have implications with respect to photochemical processes in the atmospheres of Mars and Venus.

  16. ExoMol: Large-scale production of line lists for molecules important for modelling of planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Yurchenko, S.; Tennyson, J.

    2013-09-01

    The spectral characterization of astrophysical objects cool enough to form polyatomic molecules (the atmospheres of planets, brown dwarfs, planetary discs etc.) requires a huge amount of fundamental molecular data. With a few exceptions the existing molecular line lists are not sufficiently accurate and complete. The aim of ExoMol [1] is to generate comprehensive line lists for all molecules likely to be observable in exoplanet atmospheres in the foreseeable future (see www.exomol.com for more details). We identified the following 40 species that are important sources of opacity in (exo)planets and brown dwarfs and where there is currently a lack of fundamental data on wavelength and temperature-dependent absorption: • Diatomics: AlO, AlH, BeH, CaH, C2, CrH, FeH, HF, HCl, KCl, MgH, MgO, NaH, NaCl, NiH, O2,SiO, SiH, S2, SH, TiH, TiO, VO, YO • Triatomics: C3, H2S, SO2 • Tetratomics: H2CO, H2CS, HCCH, HOOH, PH3,SO3 • Pentatomics: CH4, HNO3 • Larger molecules: C2H4, C2H6, C3H8, P2H2, P2H4 The production of comprehensive and very large rotation-vibration and rotation-vibration-electronic line lists requires a mixture of first principles quantum mechanical methods and empirical tuning based on laboratory spectroscopic data and makes extensive use of state-of-the-art computing. These and other aspects of molecular line lists, their production and astrophysical applications will be discussed. The contribution will make specific reference to molecules for which line lists have recently been completed or are nearing completion: phosphine, hydrogen sulphide, hydrogen peroxide, methane, formaldehyde, nitric acid as well as to a number of diatomic molecules of astrophysical importance, see Fig. 1.

  17. Compact remote Raman and LIBS system for detection of minerals, water, ices, and atmospheric gases for planetary exploration

    NASA Astrophysics Data System (ADS)

    Misra, Anupam K.; Sharma, Shiv K.; Acosta, Tayro E.; Bates, David E.

    2011-06-01

    At the University of Hawaii, we have developed a compact, portable remote Raman and Laser-Induced Breakdown Spectroscopy (LIBS) system with a 532 nm pulsed laser for planetary exploration under the Mars Instrument Development Program. The compact time-resolved remote Raman and LIBS system consists of (i) a regular 85 mm Nikon (F/1.8) camera lens with clear aperture of 50 mm as collection optics, (ii) a miniature spectrograph that occupies 1/14th the volume of a comparable commercial spectrograph from Kaiser Optical Systems Inc., (iii) a custom mini-ICCD detector, and (iv) a small frequency-doubled 532 nm Nd:YAG pulsed laser (30 mJ/pulse, 20 Hz) with a 10x beam expander. In the standoff Raman mode the system is capable of measuring various minerals, water, ices, and atmospheric gases from a 50 meter range with a 10 s integration time. At shorter distances of 10 m or less, good quality Raman spectra can be obtained within 1 s. The time-gated system is capable of detecting both the target mineral as well as the atmospheric gases before the target using their Raman fingerprints. Various materials can easily be identified through glass, plastic, and water media. The time-gating capability makes the system insensitive to window material, which is highly desirable for future missions to Venus where instruments are expected to be within the lander. The standoff LIBS range is 10 m and LIBS spectra of various minerals can be obtained with single laser pulse excitation. The standoff LIBS capability provides additional elemental verification of the targeted material.

  18. Elaboration of collisional-radiative models for flows related to planetary entries into the Earth and Mars atmospheres

    NASA Astrophysics Data System (ADS)

    Bultel, Arnaud; Annaloro, Julien

    2013-04-01

    The most relevant way to predict the excited state number density in a nonequilibrium plasma is to elaborate a collisional-radiative (CR) model taking into account most of the collisional and radiative elementary processes. Three examples of such an elaboration are given in this paper in the case of various plasma flows related to planetary atmospheric entries. The case of theoretical determination of nitrogen atom ionization or recombination global rate coefficients under electron impact is addressed first. The global rate coefficient can be implemented in multidimensional computational fluid dynamics calculations. The case of relaxation after a shock front crossing a gas of N2 molecules treated in the framework of the Rankine-Hugoniot assumptions is also studied. The vibrational and electronic specific CR model elaborated in this case allows one to understand how the plasma reaches equilibrium and to estimate the role of the radiative losses. These radiative losses play a significant role at low pressure in the third case studied. This case concerns CO2 plasma jets inductively generated in high enthalpy wind tunnels used as ground test facilities. We focus our attention on the behaviour of CO and C2 electronic excited states, the radiative signature of which can be particularly significant in this type of plasma. These three cases illustrate the elaboration of CR models and their coupling with balance equations.

  19. Using the transit of Venus to probe the upper planetary atmosphere

    E-print Network

    Reale, Fabio; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-01-01

    The atmosphere of a transiting planet shields the stellar radiation providing us with a powerful method to estimate its size and density. In particular, because of their high ionization energy, atoms with high atomic number (Z) absorb short-wavelength radiation in the upper atmosphere, undetectable with observations in visible light. One implication is that the planet should appear larger during a primary transit observed in high energy bands than in the optical band. The last Venus transit in 2012 offered a unique opportunity to study this effect. The transit has been monitored by solar space observations from Hinode and Solar Dynamics Observatory (SDO). We measure the radius of Venus during the transit in three different bands with subpixel accuracy: optical (4500A), UV (1600A, 1700A), Extreme UltraViolet (EUV, 171-335A) and soft X-rays (about 10A). We find that, while the Venus optical radius is about 80 km larger than the solid body radius (the expected opacity mainly due to clouds and haze), the radius i...

  20. High-Contrast Imaging using Adaptive Optics for Extrasolar Planet Detection

    SciTech Connect

    Evans, J W

    2006-08-18

    Direct imaging of extrasolar planets is an important, but challenging, next step in planetary science. Most planets identified to date have been detected indirectly--not by emitted or reflected light but through the effect of the planet on the parent star. For example, radial velocity techniques measure the doppler shift in the spectrum of the star produced by the presence of a planet. Indirect techniques only probe about 15% of the orbital parameter space of our solar system. Direct methods would probe new parameter space, and the detected light can be analyzed spectroscopically, providing new information about detected planets. High contrast adaptive optics systems, also known as Extreme Adaptive Optics (ExAO), will require contrasts of between 10{sup -6} and 10{sup -7} at angles of 4-24 {lambda}/D on an 8-m class telescope to image young Jupiter-like planets still warm with the heat of formation. Contrast is defined as the intensity ratio of the dark wings of the image, where a planet might be, to the bright core of the star. Such instruments will be technically challenging, requiring high order adaptive optics with > 2000 actuators and improved diffraction suppression. Contrast is ultimately limited by residual static wavefront errors, so an extrasolar planet imager will require wavefront control with an accuracy of better than 1 nm rms within the low- to mid-spatial frequency range. Laboratory demonstrations are critical to instrument development. The ExAO testbed at the Laboratory for Adaptive Optics was designed with low wavefront error and precision optical metrology, which is used to explore contrast limits and develop the technology needed for an extrasolar planet imager. A state-of-the-art, 1024-actuator micro-electrical-mechanical-systems (MEMS) deformable mirror was installed and characterized to provide active wavefront control and test this novel technology. I present 6.5 x 10{sup -8} contrast measurements with a prolate shaped pupil and flat mirror demonstrating that the testbed can operate in the necessary contrast regime. Wavefront measurements and simulations indicate that contrast is limited by wavefront error, not diffraction. I demonstrate feasibility of the MEMS deformable mirror for meeting the stringent residual wavefront error requirements of an extrasolar planet imager with closed-loop results of 0.54 nm rms within controllable spatial frequencies. Individual contributors to final wavefront quality have been identified and characterized. I also present contrast measurements of 2 x 10{sup -7} made with the MEMS device and identify amplitude errors as the limiting error source. Closed-loop performance and simulated far-field measurements using a Kolmogorov phase plate to introduce atmosphere-like optical errors are also presented.

  1. Shock-induced CO2 loss from CaCO3: Implications for early planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Lange, M. A.; Ahrens, T. J.

    1984-01-01

    Recovered samples from shock recovery experiments on single crystal calcite were subjected to thermogravimetric analysis to determine the amount of post-shock CO2, the decarbonization interval and the activation energy, for the removal of remaining CO2 in shock-loaded calcite. Comparison of post-shock CO2 with that initially present determines shock-induced CO2 loss as a function of shock pressure. Incipient to complete CO2 loss occurs over a pressure range of approximately 10 to approximately 70 GPa. Optical and scanning electron microscopy reveal structural changes, which are related to the shock-loading. The occurrence of dark, diffuse areas, which can be resolved as highly vesicular areas as observed with a scanning electron microscope are interpreted as representing quenched partial melts, into which shock-released CO2 was injected. The experimental results are used to constrain models of shock-produced, primary CO2 atmospheres on the accreting terrestrial planets.

  2. Impact induced dehydration of serpentine and the evolution of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Lange, M. A.; Ahrens, T. J.

    1982-01-01

    Results of shock recovery experiments carried out on antigorite serpentine Mg3Si2O5(OH)4 are reported. The main objective of the present study is the determination of critical shock pressures for partial and complete dehydration of serpentine under shock loading. It is pointed out that serpentine and serpentine-like layer silicates are the major water-bearing phases in carbonaceous chondrites. It appears that these minerals, and a poorly defined cometary contribution, were the most likely water-bearing phases in accreting planetesimals which led to the formation of the terrestrial planets. The obtained results imply that the process of impact induced devolatilization of volatile bearing minerals during accretion is likely to have occurred on earth. The findings lend support to the model of a terrestrial atmosphere/hydrosphere forming during the later stages of accretion of the earth.

  3. An investigation of low-frequency planetary wave forcing and predictability in a simple global atmospheric circulation model

    NASA Astrophysics Data System (ADS)

    Stewart, Douglas A.

    1992-01-01

    Dynamically consistent data generated by a simple 2-level global spectral model are used in conjunction with a diagnostic method to study the forcing of large-scale low-frequency (LF) atmospheric fluctuations. Run in perpetual January mode at moderate spatial resolution (i.e., R15 truncation), the model realistically simulates pertinent features of the observed time-mean climate and variability. The diagnostic method consists of calculating, from the R15 model output, the terms of the governing equations of a hypothetical low-order model that simulates only the slowly-evolving planetary-scale flow. The right hand sides of these low-pass-filtered equations are expressed in terms of resolved forcing and unresolved forcing, with the former representing autonomous processes involving only the large-scale LF components of the flow, and the latter containing the effects of high-frequency (HF) transient eddies. The roles of resolved and unresolved forcing during the various stages of composite positive and negative persistent anomalies are assessed. During anomaly maintenance, HF transient eddies anchor anomalies against downstream propagation and resist local decay. In contrast, the thermal forcing of the HF eddies acts in a destructive sense. Applying the diagnostic method to the onset stage suggests that autonomous processes typically determine the local growth of both positive and negative anomalies, consistent with interpreting their origin as a large-scale instability. The development of anomalies in HF transient eddy forcing, in general, stem from the evolution of the large-scale flow, rather than acting independently to initiate the large-scale anomaly development. A low-order model is constructed to simulate the dynamics of slowly-evolving planetary-scale flow. Relationships between the resolved and unresolved forcing gleaned from the diagnostic phase of the study are exploited in the development of a quasi-stochastic parameterization of the latter in terms of the former. The skill of the low-order model is tested against the low-pass-filtered output from the R15 model by performing a series of Monte Carlo experiments. The low-order model produces skillful forecasts out to ten days. RMS errors in the upper layer streamfunction predictions grow most rapidly in the storm track regions, and are correlated most strongly with the HF transient kinetic energy patterns.

  4. A Investigation of Low-Frequency Planetary Wave Forcing and Predictability in a Simple Global Atmospheric Circulation Model

    NASA Astrophysics Data System (ADS)

    Stewart, Douglas A.

    Dynamically consistent data generated by a simple 2-level global spectral model are used in conjunction with a diagnostic method to study the forcing of large-scale low-frequency (LF) atmospheric fluctuations. Run in perpetual January mode at moderate spatial resolution (i.e., R15 truncation), the model realistically simulates pertinent features of the observed time-mean climate and variability. The diagnostic method consists of calculating, from the R15 model output, the terms of the governing equations of a hypothetical low-order model that simulates only the slowly -evolving planetary-scale flow. The right hand sides of these low-pass-filtered equations are expressed in terms of resolved forcing and unresolved forcing, with the former representing autonomous processes involving only the large -scale LF components of the flow, and the latter containing the effects of high-frequency (HF) transient eddies. The roles of resolved and unresolved forcing during the various stages of composite positive and negative persistent anomalies are assessed. During anomaly maintenance, HF transient eddies anchor anomalies against downstream propagation and resist local decay. In contrast, the thermal forcing of the HF eddies acts in a destructive sense. Applying the diagnostic method to the onset stage suggests that autonomous processes typically determine the local growth of both positive and negative anomalies, consistent with interpreting their origin as a large-scale instability. The development of anomalies in HF transient eddy forcing, in general, stem from the evolution of the large-scale flow, rather than acting independently to initiate the large-scale anomaly development. A low-order model is constructed to simulate the dynamics of slowly-evolving planetary-scale flow. Relationships between the resolved and unresolved forcing gleaned from the diagnostic phase of the study are exploited in the development of a quasi-stochastic parameterization of the latter in terms of the former. The skill of the low-order model is tested against the low-pass-filtered output from the R15 model by performing a series of Monte Carlo experiments. The low-order model produces skillful forecasts out to ten days. RMS errors in the upper layer streamfunction predictions grow most rapidly in the storm track regions, and are correlated most strongly with the HF transient kinetic energy patterns.

  5. The Twenty-Fifth Lunar and Planetary Science Conference. Part 1: A-G

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, and planetary mantles.

  6. Detecting Extrasolar Planets with Integral Field Spectroscopy

    E-print Network

    A. Berton; R. G. Gratton; M. Feldt; T. Henning; S. Desidera; M. Turatto; H. M. Schmid; R. Waters

    2006-05-11

    Observations of extrasolar planets using Integral Field Spectroscopy (IFS), if coupled with an extreme Adaptive Optics system and analyzed with a Simultaneous Differential Imaging technique (SDI), are a powerful tool to detect and characterize extrasolar planets directly; they enhance the signal of the planet and, at the same time, reduces the impact of stellar light and consequently important noise sources like speckles. In order to verify the efficiency of such a technique, we developed a simulation code able to test the capabilities of this IFS-SDI technique for different kinds of planets and telescopes, modelling the atmospheric and instrumental noise sources. The first results obtained by the simulations show that many significant extrasolar planet detections are indeed possible using the present 8m-class telescopes within a few hours of exposure time. The procedure adopted to simulate IFS observations is presented here in detail, explaining in particular how we obtain estimates of the speckle noise, Adaptive Optics corrections, specific instrumental features, and how we test the efficiency of the SDI technique to increase the signal-to-noise ratio of the planet detection. The most important results achieved by simulations of various objects, from 1 M_J to brown dwarfs of 30 M_J, for observations with an 8 meter telescope, are then presented and discussed.

  7. A Nongray Theory of Extrasolar Giant Planets and Brown Dwarfs

    Microsoft Academic Search

    A. Burrows; M. Marley; W. B. Hubbard; J. I. Lunine; T. Guillot; D. Saumon; R. Freedman; D. Sudarsky; C. Sharp

    1997-01-01

    We present the results of a new series of nongray calculations of the atmospheres, spectra, colors, and evolution of extrasolar giant planets (EGPs) and brown dwarfs for effective temperatures below 1300 K. This theory encompasses most of the mass\\/age parameter space occupied by substellar objects and is the first spectral study down to 100 K. These calculations are in aid

  8. The Survival of Water Within Extrasolar Minor Planets

    Microsoft Academic Search

    M. Jura; S. Xu

    2010-01-01

    We compute that extrasolar minor planets can retain much of their internal H2O during their host star's red giant evolution. The eventual accretion of a water-rich body or bodies onto a helium white dwarf might supply an observable amount of atmospheric hydrogen, as seems likely for GD 362. More generally, if hydrogen pollution in helium white dwarfs typically results from

  9. The Outer Architecture of M Dwarf Planetary Systems

    NASA Astrophysics Data System (ADS)

    Bowler, Brendan P.; Liu, Michael C.; Shkolnik, Evgenya; Tamura, Motohide

    2015-01-01

    High-contrast imaging probes the outer architecture of planetary systems and enables direct studies of extrasolar giant planet atmospheres. M dwarfs have largely been neglected from previous surveys despite having more favorable planet-star contrasts and representing about 75% of all stars. As a result, little is known about the population of gas-giant planets at moderate separations (10-100 AU) in this stellar mass regime. I will describe results from the Planets Around Low-Mass Stars (PALMS) high-contrast adaptive optics imaging program targeting nearby (<35 pc) young (<300 Myr) M dwarfs with Keck/NIRC2 and Subaru/HiCIAO. With a sample size of over 120 stars, PALMS is the largest direct imaging planet search in this stellar mass regime. I will present the survey discoveries, statistical results, and implications for the formation of gas-giant planets around the most common stars in our galaxy.

  10. Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.

    1988-01-01

    In the first half of this grant year, laboratory measurements were conducted on the millimeter-wave properties of atmospheric gases under simulated conditions for the outer planet. Significant improvements in the current system have made it possible to accurately characterize the opacity from gaseous NH3 at longer millimeter wavelengths (7 to 10 mm) under simulated Jovian conditions. In the second half of the grant year, it is hoped to extend such measurements to even shorter millimeter-wavelengths. Further analysis and application of the laboratory results to microwave and millimeter-wave absorption data for the outer planets, such as results from Voyager Radio Occultation experiments and earth-based radio astronomical observations will be continued. The analysis of available multispectral microwave opacity data from Venus, including data from the most recent radio astronomical ovservations in the 1.3 to 3.6 cm wavelength range and newly obtained Pioneer-Venus Radio Occulatation measurements at 13 cm, using the laboratory measurements as an interpretative tool will be pursued.

  11. Microfabricated silicon leak for sampling planetary atmospheres with a mass spectrometer

    SciTech Connect

    Jamieson, B. G.; Lynch, B. A.; Harpold, D. N.; Niemann, H. B.; Shappirio, M. D.; Mahaffy, P. R. [Scientific and Biomedical Microsystems, Severna Park, Maryland 21146 (United States); MEI Technologies, Seabrook, Maryland 20706 (United States); NASA/Goddard Spaceflight Center Greenbelt, Maryland 20771 (United States)

    2007-06-15

    A microfabricated silicon mass spectrometer inlet leak has been designed, fabricated, and tested. This leak achieves a much lower conductance in a smaller volume than is possible with commonly available metal or glass capillary tubing. It will also be shown that it is possible to integrate significant additional functionality, such as inlet heaters and valves, into a silicon microleak with very little additional mass. The fabricated leak is compatible with high temperature (up to 500 deg. C) and high pressure (up to 100 bars) conditions, as would be encountered on a Venus atmospheric probe. These leaks behave in reasonable agreement with their theoretically calculated conductance, although this differs between devices and from the predicted value by as much as a factor of 2. This variation is believed to be the result of nonuniformity in the silicon etching process which is characterized in this work. Future versions of this device can compensate for characterized process variations in order to produce devices in closer agreement with designed conductance values. The integration of an inlet heater into the leak device has also been demonstrated in this work.

  12. Microfabricated silicon leak for sampling planetary atmospheres with a mass spectrometer.

    PubMed

    Jamieson, B G; Lynch, B A; Harpold, D N; Niemann, H B; Shappirio, M D; Mahaffy, P R

    2007-06-01

    A microfabricated silicon mass spectrometer inlet leak has been designed, fabricated, and tested. This leak achieves a much lower conductance in a smaller volume than is possible with commonly available metal or glass capillary tubing. It will also be shown that it is possible to integrate significant additional functionality, such as inlet heaters and valves, into a silicon microleak with very little additional mass. The fabricated leak is compatible with high temperature (up to 500 degrees C) and high pressure (up to 100 bars) conditions, as would be encountered on a Venus atmospheric probe. These leaks behave in reasonable agreement with their theoretically calculated conductance, although this differs between devices and from the predicted value by as much as a factor of 2. This variation is believed to be the result of nonuniformity in the silicon etching process which is characterized in this work. Future versions of this device can compensate for characterized process variations in order to produce devices in closer agreement with designed conductance values. The integration of an inlet heater into the leak device has also been demonstrated in this work. PMID:17614640

  13. The transport of nitric oxide in the upper atmosphere by planetary waves and the zonal mean circulation

    NASA Technical Reports Server (NTRS)

    Jones, G. A.; Avery, S. K.

    1982-01-01

    A time-dependent numerical model was developed and used to study the interaction between planetary waves, the zonal mean circulation, and the trace constituent nitric oxide in the region between 55 km and 120 km. The factors which contribute to the structure of the nitric oxide distribution were examined, and the sensitivity of the distribution to changes in planetary wave amplitude was investigated. Wave-induced changes in the mean nitric oxide concentration were examined as a possible mechanism for the observed winter anomaly. Results indicate that vertically-propagating planetary waves induce a wave-like structure in the nitric oxide distribution and that at certain levels, transports of nitric oxide by planetary waves could significantly affect the mean nitric oxide distribution. The magnitude and direction of these transports at a given level was found to depend not only on the amplitude of the planetary wave, but also on the loss rate of nitric oxide at that level.

  14. Extrasolar Planets in the Classroom

    ERIC Educational Resources Information Center

    George, Samuel J.

    2011-01-01

    The field of extrasolar planets is still, in comparison with other astrophysical topics, in its infancy. There have been about 300 or so extrasolar planets detected and their detection has been accomplished by various different techniques. Here we present a simple laboratory experiment to show how planets are detected using the transit technique.…

  15. 34Modeling a Planetary Nebula Planetary nebula are the outer

    E-print Network

    34Modeling a Planetary Nebula Planetary nebula are the outer atmospheres of dying stars ejected into space. Astronomers model these nebulae to learn about the total mass they contain, and the details of how they were ejected. The image is of a rare, spherical-shell planetary nebula, Abell 38

  16. Secular Resonances In Planetary Systems

    NASA Astrophysics Data System (ADS)

    Malhotra, Renu

    2006-06-01

    Secular effects introduce very low frequencies in planetary systems. The consequences are quite varied. They include mundane effects on the planetary ephemerides and on Earthly seasons, but also more esoteric effects such as apsidal alignment or anti-alignment, fine-splitting of mean motion resonances, broadening of chaotic zones, and dramatic orbital instabilities. Secular effects may shape the overall architecture of mature planetary systems by determining the long term stability of major and minor planetary bodies. This talk will be partly tutorial and partly a review of secular resonance phenomena here in the solar system and elsewhere in extra-solar systems. I acknowledge research support from NASA-Origins of Solar Systems and NASA-Outer Planets research programs.

  17. Toward a Model for Detecting Life on Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Rye, R.; Storrie-Lombardi, M.

    2001-12-01

    The search for life extraterrestrial life has rapidly expanded during the past several years. In addition to missions to Mars and Europa, NASA now envisions launching an orbiting telescope, Terrestrial Planet Finder (TPF), capable of resolving Earth-sized planets around stars as far away as 50 parsecs within the next 10-15 years. By that time we need to develop our understanding of the effects of life on such planets in order to confidently distinguish inhabited planets from barren ones. Our group is in the process of developing a fully coupled generalized 1-D radiative transfer-atmospheric chemistry model. Around this core we are building the Virtual Planetary Laboratory (VPL) to generate synthetic spectra of hypothetical extrasolar terrestrial planets. Computational modules mimicking the influence of life on atmospheric chemistry/climate are of central importance for analyzing data from TPF and related missions. Here we describe our rationale and initial efforts to parameterize the effects of life using a Virtual Microbial Community (VMC). At first glance, the task of modeling hypothetical inhabited planets appears intractable. However, we may assume that most planets settle into a fairly small number of stable climate/chemistry regimes during their history. These regimes are maintained by negative feedback loops. Transitions from one stable solution to another are singularities, times during which the system is unregulated and may vary wildly. In this context, life is one of several processes modifying the chemical composition of a planetary atmosphere, potentially modifying climate. We seek to elucidate those processes and signatures unique to life and visible from space. The VMC is a first attempt at quantifying the possible range of effects of life on the atmosphere of a planet. We start from the presumption that kinetics and thermodynamics are the same throughout the universe. Given the remarkable metabolic diversity of life on Earth, we assume that all available energy sources may be used by biology on detectably colonized planets. Simple feedback loops such as those governing Lovelock?s famous Daisyworld or the Walker CO2 feedback, offer starting points for thinking about global scale feedbacks. Feedbacks in microbial communities, e.g. those postulated in anaerobic methane oxidation communities, involving the use of one or more organisms? waste products as nutrients by another, hint at the local complexity from which we need to scale up. Our first attempt at bridging this gap involves describing the processes that may have helped stabilize the Archean climate. Archean biogenic methane production could have been rapid enough to provide 100s ppm atmospheric CH4. At such CH4 levels Earth would have remained ice free. Sudden increases in CH4 production might have led to runaway greenhouse conditions. However, if CH4/CO2 > 1 a UV absorbing aerosol haze should form. UV-labile ammonia could have accumulated in the atmosphere under the haze, quickly making rain pH > 7, dramatically slowing chemical weathering on the continents and interrupting vital phosphate delivery to the oceans. The residence time of P is ca.10,000 years. Thus, over a time scale of ca.10,000 years primary productivity dropped sharply. Biogenic methane production, near the base of the trophic ladder, suffered disproportionately. With little CH4 production CH4/CO2 fell to < 1. The UV screen and atmospheric NH3 disappeared in a few years. Rain pH dropped. Weathering restarted. Biological productivity recovered. The above testable scenario serves as an example of a plausible feedback involving interplay between biological, geochemical, atmospheric and stellar processes. Feedback loops of this sort will be central features of the fully realized VMC module for the VPL.

  18. Photometric Light Curves and Polarization of Close-in Extrasolar Giant Planets

    Microsoft Academic Search

    S. Seager; B. A. Whitney; D. D. Sasselov

    2000-01-01

    The close-in extrasolar giant planets (CEGPs), <~0.05 AU from their parent stars, may have a large component of optically reflected light. We present theoretical optical photometric light curves and polarization curves for the CEGP systems from reflected planetary light. Different particle sizes of three condensates are considered. In the most reflective case, the variability is ~100 mumag, which will be

  19. The Use of High-Magnification Microlensing Events in Discovering Extrasolar Planets

    Microsoft Academic Search

    Kim Griest; Neda Safizadeh

    1998-01-01

    Hundreds of gravitational microlensing events have now been detected toward the Galactic bulge, with many more to come. The detection of fine structure in these events has been theorized as an excellent way to discover extrasolar planetary systems along the line of sight to the Galactic center. We show that by focusing on high-magnification events, the probability of detecting planets

  20. CO Emissions from Cometary and Planetary Atmospheres as a Marker for CO2

    NASA Astrophysics Data System (ADS)

    Kalogerakis, K.; Romanescu, C.; Ahmed, M.; Wilson, K. R.; Slanger, T. G.

    2012-12-01

    Photodissociation of CO2 in the atmosphere of Mars leads to dayglow emissions in the 190-250 nm region from the CO(a-X) Cameron bands, the 290-nm CO2+ (B-X) band, the 300-400 nm CO2+ (A-X) system, and the 297-nm O(1S-3P) line [1]. Very recently, detectors on Venus Express have shown the same emissions at that planet with an order of magnitude higher intensity [2], approximately 2 MR on the limb. It has been generally assumed that production of the CO(a) state is direct, i.e., CO2 is photodissociated by photons with wavelengths less than the 108-nm threshold to produce CO(a) + O(3P). Experiments at the Advanced Light Source (ALS) in Berkeley indicate that this scenario is incorrect, and that CO(a) production arises mainly from cascading from higher CO triplet states with a threshold of 100 nm [3]. The cascading process results in initial emission in the visible and infrared (IR), followed by the Cameron band emission. As a result, there are discrepancies between the observations and models and, furthermore, there has never been an attempt to monitor the strong unquenched CO dayglow emission in the visible and IR at Mars/Venus. On the other hand, cometary spectra in these wavelength regions are obtained from the ground, and a serious effort should be made to identify the very complex CO bands. [1] C. A. Barth et al., J. Geophys. Res. 76, 2213-2227 (1971). [2] J.-L. Bertaux et al., Geophys. Res. Abstracts, 14, EGU 2012-8097 (2012). [3] K. S. Kalogerakis et al., Icarus 220, 205-210 (2012). The ALS experiments were performed under grant NNX06AB82G from the NASA Outer Planets Research Program to SRI International. Partial support for K.S. Kalogerakis from NSF grants AST-0709173 and AST-1109372 is also acknowledged. M. Ahmed, K.R. Wilson, and the ALS are supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Chemical Sciences Division of the U.S. Department of Energy under contract No. DE-AC02-05CH11231.

  1. 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.

  2. Direct imaging of extra-solar planets

    SciTech Connect

    Olivier, S.S.; Max, V.E.; Brase, J.M.; Caffano, C.J.; Gavel, D.T.; Macintosh, B.A.

    1997-03-01

    Direct imaging of extra-solar planets may be possible with the new generation of large ground-based telescopes equipped with state- of- the-art adaptive optics (AO) systems to compensate for the blurring effect of the Earth`s atmosphere. The first of these systems is scheduled to begin operation in 1998 on the 10 in Keck II telescope. In this paper, general formulas for high-contrast imaging with AO systems are presented and used to calculate the sensitivity of the Keck AO system. The results of these calculations show that the Keck AO system should achieve the sensitivity necessary to detect giant planets around several nearby bright stars.

  3. Twenty-Fourth Lunar and Planetary Science Conference. Part 2: G-M

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The topics covered include the following: meteorites, meteoritic composition, geochemistry, planetary geology, planetary composition, planetary craters, the Moon, Mars, Venus, asteroids, planetary atmospheres, meteorite craters, space exploration, lunar geology, planetary surfaces, lunar surface, lunar rocks, lunar soil, planetary atmospheres, lunar atmosphere, lunar exploration, space missions, geomorphology, lithology, petrology, petrography, planetary evolution, Earth surface, planetary surfaces, volcanology, volcanos, lava, magma, mineralogy, minerals, ejecta, impact damage, meteoritic damage, tectonics, etc.

  4. 3D climate modeling of Earth-like extrasolar planets orbiting different types of host stars

    NASA Astrophysics Data System (ADS)

    Godolt, M.; Grenfell, J. L.; Hamann-Reinus, A.; Kitzmann, D.; Kunze, M.; Langematz, U.; von Paris, P.; Patzer, A. B. C.; Rauer, H.; Stracke, B.

    2015-06-01

    The potential habitability of a terrestrial planet is usually defined by the possible existence of liquid water on its surface, since life as we know it needs liquid water at least during a part of its life cycle. The potential presence of liquid water on a planetary surface depends on many factors such as, most importantly, surface temperatures. The properties of the planetary atmosphere and its interaction with the radiative energy provided by the planet's host star are thereby of decisive importance. In this study we investigate the influence of different main-sequence stars (F, G, and K-type stars) upon the climate of Earth-like extrasolar planets and their potential habitability by applying a state-of-the-art three-dimensional (3D) Earth climate model accounting for local and dynamical processes. The calculations have been performed for planets with Earth-like atmospheres at orbital distances (and corresponding orbital periods) where the total amount of energy received from the various host stars equals the solar constant. In contrast to previous 3D modeling studies, we include the effect of ozone radiative heating upon the vertical temperature structure of the atmospheres. The global orbital mean results obtained have been compared to those of a one-dimensional (1D) radiative convective climate model to investigate the approximation of global mean 3D results by those of 1D models. The different stellar spectral energy distributions lead to different surface temperatures and due to ozone heating to very different vertical temperature structures. As previous 1D studies we find higher surface temperatures for the Earth-like planet around the K-type star, and lower temperatures for the planet around the F-type star compared to an Earth-like planet around the Sun. However, this effect is more pronounced in the 3D model results than in the 1D model because the 3D model accounts for feedback processes such as the ice-albedo and the water vapor feedback. Whether the 1D model may approximate the global mean of the 3D model results strongly depends on the choice of the relative humidity profile in the 1D model, which is used to determine the water vapor profile. Hence, possible changes in the hydrological cycle need to be accounted for when estimating the potential habitability of an extrasolar planet.

  5. Earth as an extrasolar planet: Earth model validation using EPOXI earth observations.

    PubMed

    Robinson, Tyler D; Meadows, Victoria S; Crisp, David; Deming, Drake; A'hearn, Michael F; Charbonneau, David; Livengood, Timothy A; Seager, Sara; Barry, Richard K; Hearty, Thomas; Hewagama, Tilak; Lisse, Carey M; McFadden, Lucy A; Wellnitz, Dennis D

    2011-06-01

    The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ?100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ?10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ?7% and brightness temperature errors of less than 1?K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be used to simulate Earth's time-dependent brightness and spectral properties for wavelengths from the far ultraviolet to the far infrared. Key Words: Astrobiology-Extrasolar terrestrial planets-Habitability-Planetary science-Radiative transfer. Astrobiology 11, 393-408. PMID:21631250

  6. Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations

    PubMed Central

    Meadows, Victoria S.; Crisp, David; Deming, Drake; A'Hearn, Michael F.; Charbonneau, David; Livengood, Timothy A.; Seager, Sara; Barry, Richard K.; Hearty, Thomas; Hewagama, Tilak; Lisse, Carey M.; McFadden, Lucy A.; Wellnitz, Dennis D.

    2011-01-01

    Abstract The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ?100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ?10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ?7% and brightness temperature errors of less than 1?K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be used to simulate Earth's time-dependent brightness and spectral properties for wavelengths from the far ultraviolet to the far infrared. Key Words: Astrobiology—Extrasolar terrestrial planets—Habitability—Planetary science—Radiative transfer. Astrobiology 11, 393–408. PMID:21631250

  7. PHOTOMETRIC ORBITS OF EXTRASOLAR PLANETS

    SciTech Connect

    Brown, Robert A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)], E-mail: rbrown@stsci.edu

    2009-09-10

    We define and analyze the photometric orbit (PhO) of an extrasolar planet observed in reflected light. In our definition, the PhO is a Keplerian entity with six parameters: semimajor axis, eccentricity, mean anomaly at some particular time, argument of periastron, inclination angle, and effective radius, which is the square root of the geometric albedo times the planetary radius. Preliminarily, we assume a Lambertian phase function. We study in detail the case of short-period giant planets (SPGPs) and observational parameters relevant to the Kepler mission: 20 ppm photometry with normal errors, 6.5 hr cadence, and three-year duration. We define a relevant 'planetary population of interest' in terms of probability distributions of the PhO parameters. We perform Monte Carlo experiments to estimate the ability to detect planets and to recover PhO parameters from light curves. We calibrate the completeness of a periodogram search technique, and find structure caused by degeneracy. We recover full orbital solutions from synthetic Kepler data sets and estimate the median errors in recovered PhO parameters. We treat in depth a case of a Jupiter body-double. For the stated assumptions, we find that Kepler should obtain orbital solutions for many of the 100-760 SPGP that Jenkins and Doyle estimate Kepler will discover. Because most or all of these discoveries will be followed up by ground-based radial velocity observations, the estimates of inclination angle from the PhO may enable the calculation of true companion masses: Kepler photometry may break the 'msin i' degeneracy. PhO observations may be difficult. There is uncertainty about how low the albedos of SPGPs actually are, about their phase functions, and about a possible noise floor due to systematic errors from instrumental and stellar sources. Nevertheless, simple detection of SPGPs in reflected light should be robust in the regime of Kepler photometry, and estimates of all six orbital parameters may be feasible in at least a subset of cases.

  8. Predicting low-frequency radio fluxes of known extrasolar planets

    E-print Network

    J. -M. Grießmeier; P. Zarka; H. Spreeuw

    2008-06-02

    Context. Close-in giant extrasolar planets (''Hot Jupiters'') are believed to be strong emitters in the decametric radio range. Aims. We present the expected characteristics of the low-frequency magnetospheric radio emission of all currently known extrasolar planets, including the maximum emission frequency and the expected radio flux. We also discuss the escape of exoplanetary radio emission from the vicinity of its source, which imposes additional constraints on detectability. Methods. We compare the different predictions obtained with all four existing analytical models for all currently known exoplanets. We also take care to use realistic values for all input parameters. Results. The four different models for planetary radio emission lead to very different results. The largest fluxes are found for the magnetic energy model, followed by the CME model and the kinetic energy model (for which our results are found to be much less optimistic than those of previous studies). The unipolar interaction model does not predict any observable emission for the present exoplanet census. We also give estimates for the planetary magnetic dipole moment of all currently known extrasolar planets, which will be useful for other studies. Conclusions. Our results show that observations of exoplanetary radio emission are feasible, but that the number of promising targets is not very high. The catalog of targets will be particularly useful for current and future radio observation campaigns (e.g. with the VLA, GMRT, UTR-2 and with LOFAR).

  9. Quantifying the Uncertainty in the Orbits of Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Ford, Eric B.

    2005-03-01

    Precise radial velocity measurements have led to the discovery of ~100 extrasolar planetary systems. We investigate the uncertainty in the orbital solutions that have been fitted to these observations. Understanding these uncertainties will become more and more important as the discovery space for extrasolar planets shifts to longer and longer periods. While detections of short-period planets can be rapidly refined, planets with long orbital periods will require observations spanning decades to constrain the orbital parameters precisely. Already in some cases, multiple distinct orbital solutions provide similarly good fits, particularly in multiple-planet systems. We present a method for quantifying the uncertainties in orbital fits and addressing specific questions directly from the observational data rather than relying on best-fit orbital solutions. This Markov chain Monte Carlo (MCMC) technique has the advantage that it is well suited to the high-dimensional parameter spaces necessary for the multiple-planet systems. We apply the MCMC technique to several extrasolar planetary systems, assessing the uncertainties in orbital elements for several systems. Our MCMC simulations demonstrate that for some systems there are strong correlations between orbital parameters and/or significant non-Gaussianities in parameter distributions, even though the measurement errors are nearly Gaussian. Once these effects are considered, the actual uncertainties in orbital elements can be significantly larger or smaller than the published uncertainties. We also present simple applications of our methods, such as predicting the times of possible transits for GJ 876.

  10. Planetary Astronomy

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1998-01-01

    This 1-year project was an augmentation grant to my NASA Planetary Astronomy grant. With the awarded funding, we accomplished the following tasks: (1) Conducted two NVK imaging runs in conjunction with the ILAW (International Lunar Atmosphere Week) Observing Campaigns in 1995 and 1997. In the first run, we obtained repeated imaging sequences of lunar Na D-line emission to better quantify the temporal variations detected in earlier runs. In the second run we obtained extremely high resolution (R=960.000) Na line profiles using the 4m AAT in Australia. These data are being analyzed under our new 3-year Planetary Astronomy grant. (2) Reduced, analyzed, and published our March 1995 spectroscopic dataset to detect (or set stringent upper limits on) Rb. Cs, Mg. Al. Fe, Ba, Ba. OH, and several other species. These results were reported in a talk at the LPSC and in two papers: (1) A Spectroscopic Survey of Metallic Abundances in the Lunar Atmosphere. and (2) A Search for Magnesium in the Lunar Atmosphere. Both reprints are attached. Wrote up an extensive, invited Reviews of Geophysics review article on advances in the study of the lunar atmosphere. This 70-page article, which is expected to appear in print in 1999, is also attached.

  11. Spectroscopic planetary detection

    NASA Technical Reports Server (NTRS)

    Deming, Drake

    1991-01-01

    One of the most promising methods for the detection of extra-solar planets is the spectroscopic method, where a small Doppler shift (approx. 10 meter/sec) in the spectrum of the parent star reveals the presence of planetary companions. However, solar type stars may show spurious Doppler shifts due to surface activity. If these effects are periodic, as is the solar activity cycle, then they may masquerade as planetary companions. The goal of this study was to determine whether the solar cycle affects the Doppler stability of integrated sunlight. Observations of integrated sunlight were made in the near infrared (approx. 2 micron), using the Kitt Peak McMath Fourier transform spectrometer, with a N2O gas absorption cell for calibration. An accuracy of approx. 5 meter/sec was achieved.

  12. Theoretical Transmission Spectra during Extrasolar Giant Planet Transits

    Microsoft Academic Search

    S. Seager; D. D. Sasselov

    2000-01-01

    The recent transit observation of HD 209458 b-an extrasolar planet orbiting a Sun-like star-confirmed that it is a gas giant and determined that its orbital inclination is 85°. This inclination makes possible investigations of the planet atmosphere. In this paper we discuss the planet transmission spectra during a transit. The basic tenet of the method is that the planet atmosphere

  13. Schumann Resonance: A Tool for Investigating Planetary Atmospheric Electricity and the Origin and Evolution of the Solar System

    NASA Astrophysics Data System (ADS)

    Simoes, F.; Pfaff, R. F.; Hamelin, M.; Beghin, C.; Berthelier, J.-J.; Chamberlin, P.; Farrell, W.; Freudenreich, H.; Grard, R.; Klenzing, J.; Lebreton, J.-P.; Martin, S.; Rowland, D.; Yair, Y.

    2012-10-01

    In this work we discuss a new technique and associated instrumentation to detect Schumann resonance signatures of planetary environments and subsequently to infer the fraction of volatiles in the gaseous envelopes of the giant planets.

  14. Detection of Thermal Emission from an Extrasolar Planet

    E-print Network

    David Charbonneau; Lori E. Allen; S. Thomas Megeath; Guillermo Torres; Roi Alonso; Timothy M. Brown; Ronald L. Gilliland; David W. Latham; Georgi Mandushev; Francis T. O'Donovan; Alessandro Sozzetti

    2005-03-21

    We present Spitzer Space Telescope infrared photometric time series of the transiting extrasolar planet system TrES-1. The data span a predicted time of secondary eclipse, corresponding to the passage of the planet behind the star. In both bands of our observations, we detect a flux decrement with a timing, amplitude, and duration as predicted by published parameters of the system. This signal represents the first direct detection of (i.e. the observation of photons emitted by) a planet orbiting another star. The observed eclipse depths (in units of relative flux) are 0.00066 +/- 0.00013 at 4.5um and 0.00225 +/- 0.00036 at 8.0um. These estimates provide the first observational constraints on models of the thermal emission of hot Jupiters. Assuming that the planet emits as a blackbody, we estimate an effective temperature of T_p=1060 +/- 50 K. Under the additional assumptions that the planet is in thermal equilibrium with the radiation from the star and emits isotropically, we find a Bond albedo of A = 0.31 +/- 0.14. This would imply that the planet absorbs the majority of stellar radiation incident upon it, a conclusion of significant impact to atmospheric models of these objects. We compare our data to a previously-published model of the planetary thermal emission, which predicts prominent spectral features in our observational bands due to water and carbon monoxide. Based on the time of secondary eclipse, we present an upper limit on the orbital eccentricity that is sufficiently small that we conclude that tidal dissipation is unlikely to provide a significant source of energy interior to the planet.(abridged)

  15. Constraints on planetary habitability from interior modelling

    NASA Astrophysics Data System (ADS)

    Noack, Lena; Godolt, Mareike; von Paris, Philip; Plesa, Ana-Catalina; Stracke, Barbara; Breuer, Doris; Rauer, Heike

    2013-04-01

    The most interesting planetary bodies outside the Solar System regarding the search for life are potentially rocky extrasolar planets. Some of them may feature surface conditions that allow for liquid water, which is the elementary prerequisite for life as we know it. The amount of greenhouse gases, like e.g. carbon dioxide (CO2), plays an important role for the determination of the surface temperature, hence the habitability of an extrasolar planet. The amount of greenhouse gases is strongly influenced by their outgassing from the interior. In this study, we investigate under which conditions the planetary interior structure and dynamics allow for the build-up of planetary atmospheres which may lead to habitable surface conditions. We investigate the evolution of a secondary atmosphere for Earth-sized planets with different interior structures (i.e. iron-silicate mixing ratios) by applying a two-dimensional model of interior dynamics [1], which allows for the calculation of the production of partial melt [2]. From this, we estimate the amount of CO2 outgassing for Earth-sized planets with different core and mantle radii after adapting the total CO2 outgassing in 4.5 Gyr for a Venus reference simulation to the present-day atmosphere of Venus. We furthermore investigate the possible influence of plate tectonics on outgassing and the likelihood of plate tectonics depending on the interior structure of the planet. We find that the size of the iron core has a large impact on the production of partial melt, hence on the possible outgassing of CO2, which is due to the pressure-dependence of the melting temperature of silicate rocks: for planets with a large core the planetary mass is larger than for a planet with a small iron core, leading to larger melting temperatures in the upper mantle. Therefore only little outgassing from the interior can be expected. However, for the determination of the outer edge of the habitable zone it is typically assumed that enough greenhouse gas CO2 is available in the atmosphere to lead to liquid water at the surface - independent of the interior of the planet [3]. Our results on the other hand suggest that the outer boundary of the habitable zone may be constrained by the production of partial melt in the interior for planets with a large iron core and a thin silicate mantle. However, if plate tectonics initiates, several tens of bars of CO2 can be outgassed in a short time also for planets with a large iron core. In this case the outer boundary of the habitable zone would not be limited by outgassing as is the case for stagnant-lid planets. It is, however, questionable if planets with a very thin mantle are able to initiate plate tectonics. References [1] Hüttig, C. and Stemmer, K. (2008), PEPI, 171(1-4):137-146. [2] Plesa, A.-C. and Spohn, T. (2012), Transactions of the HLRS 2011, Springer, 551-565. [3] Kasting, J., Whitmire, D.P. and Reynolds, R.T. (1993), Icarus, 101:108-128.

  16. A survey of bimolecular ion-molecule reactions for use in modeling the chemistry of planetary atmospheres, cometary comae, and interstellar clouds - 1993 supplement

    NASA Technical Reports Server (NTRS)

    Anicich, V. G.

    1993-01-01

    This is a supplement to a previous paper (Anicich & Huntress 1986). It is a survey of bimolecular positive ion-molecule reactions with potential importance to the chemistry of planetary atmospheres, cometary comae, and interstellar clouds. This supplement covers the literature from 1986 through 1991, with some additional citations missed in the original survey. Over 200 new citations are included. A table of reactions is listed by reactant ion, and cross-references are provided for both ionic and neutral reactants and also for both ionic and neutral products.

  17. Planetary migration

    E-print Network

    Philip J. Armitage; W. K. M. Rice

    2005-09-08

    Gravitational torques between a planet and gas in the protoplanetary disk result in orbital migration of the planet, and are likely to play an important role in the formation and early evolution of planetary systems. For masses comparable to those of observed giant extrasolar planets, the interaction with the disk is strong enough to form a gap, leading to coupled evolution of the planet and disk on a viscous time scale (Type II migration). Both the existence of hot Jupiters, and the statistical distribution of observed orbital radii, are consistent with an important role for Type II migration in the history of currently observed systems. We discuss the possibility of improving constraints on migration by including information on the host stars' metallicity, and note that migration could also form a population of massive planets at large orbital radii that may be indirectly detected via their influence on debris disks. For lower mass planets with masses of the order of that of the Earth, surface density perturbations created by the planet are small, and migration in a laminar disk is driven by an intrinsic and apparently robust asymmetry between interior and exterior torques. Analytic and numerical calculations of this Type I migration are in reasonable accord, and predict rapid orbital decay during the final stages of the formation of giant planet cores. The difficulty of reconciling Type I migration with giant planet formation may signal basic errors in our understanding of protoplanetary disks, core accretion, or both. We discuss physical effects that might alter Type I behavior, in particular the possibility that for sufficiently low masses turbulent fluctuations in the gas surface density dominate the torque, leading to random walk migration of very low mass bodies.

  18. Discovery of Planetary Systems With SIM

    NASA Technical Reports Server (NTRS)

    Marcy, Geoffrey W.; Butler, Paul R.; Frink, Sabine; Fischer, Debra; Oppenheimer, Ben; Monet, David G.; Quirrenbach, Andreas; Scargle, Jeffrey D.

    2004-01-01

    We are witnessing the birth of a new observational science: the discovery and characterization of extrasolar planetary systems. In the past five years, over 70 extrasolar planets have been discovered by precision Doppler surveys, most by members of this SIM team. We are using the data base of information gleaned from our Doppler survey to choose the best targets for a new SIN planet search. In the same way that our Doppler database now serves SIM, our team will return a reconnaissance database to focus Terrestrial Planet Finder (TPF) into a more productive, efficient mission.

  19. A TIME-DEPENDENT RADIATIVE MODEL FOR THE ATMOSPHERE OF THE ECCENTRIC EXOPLANETS

    SciTech Connect

    Iro, N. [LESIA, Observatoire de Paris-Meudon, place Jules Janssen, 92395 Meudon Cedex (France); Deming, L. D., E-mail: nicolas.iro@nasa.go, E-mail: leo.d.deming@nasa.go [NASA/Goddard Space Flight Center, Planetary Systems Laboratory, Code 693, Greenbelt, MD 20771 (United States)

    2010-03-20

    We present a time-dependent radiative model for the atmosphere of extrasolar planets that takes into account the eccentricity of their orbit. In addition to the modulation of stellar irradiation by the varying planet-star distance, the pseudo-synchronous rotation of the planets may play a significant role. We include both of these time-dependent effects when modeling the planetary thermal structure. We investigate the thermal structure and spectral characteristics for time-dependent stellar heating for two highly eccentric planets. Finally, we discuss observational aspects for those planets suitable for Spitzer measurements and investigate the role of the rotation rate.

  20. Mean Motion Resonances and the Origins of Extrasolar Orbital Architectures

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin; Morbidelli, Alessandro

    2015-05-01

    The early stages of dynamical evolution of planetary systems are often shaped by dissipative processes that drive orbital migration. In multi-planet systems, convergent amassing of orbits inevitably leads to encounters with rational period ratios, which may result in establishment of mean motion resonances. The success or failure of resonant capture yields exceedingly different subsequent evolutions, and thus plays a central role in determining the ensuing orbital architecture of planetary systems. In this talk, we will show how an integrable Hamiltonian formalism for planetary resonances that allows both secondary bodies to have finite masses and eccentricities, can be used to construct a comprehensive theory for resonant capture. Employing the developed analytical model, we shall examine the origins of the dominantly non-resonant orbital distribution of sub-Jovian extrasolar planets, and demonstrate that the commonly observed extrasolar orbital structure can be understood if planet pairs encounter mean motion commensurabilities on slightly eccentric (e ~ 0.02) orbits. Accordingly, we speculate that resonant capture among low-mass planets is typically rendered unsuccessful due to subtle axial asymmetries inherent to the global structure of protoplanetary disks.

  1. Microlensing search for extrasolar planets: observational strategy, discoveries and implications

    E-print Network

    Arnaud Cassan; Takahiro Sumi; Daniel Kubas

    2007-11-29

    Microlensing has proven to be a valuable tool to search for extrasolar planets of Jovian- to Super-Earth-mass planets at orbits of a few AU. Since planetary signals are of very short duration, an intense and continuous monitoring is required. This is achieved by ground-based networks of telescopes (PLANET/RoboNET, microFUN) following up targets, which are identified as microlensing events by single dedicated telescopes (OGLE, MOA). Microlensing has led to four already published detections of extrasolar planets, one of them being OGLE-2005-BLG-390Lb, a planet of only ~5.5 M_earth orbiting its M-dwarf host star at ~2.6 AU. Very recent observations (May--September 2007) provided more planetary candidates, still under study, that will double the number of detections. For non-planetary microlensing events observed from 1995 to 2006 we compute detection efficiency diagrams, which can then be used to derive an estimate of the Galactic abundance of cool planets in the mass regime from Jupiters to Sub-Neptunes.

  2. 50&100YEARSAGO EXTRASOLAR PLANETS

    E-print Network

    Royer, Dana

    of the powerful greenhouse gas methane (CH4) in planetary atmospheres. In Earth'satmosphere,thedominant sources of alcohol and road safety has been much in the public eye, there has hitherto been little precise evidence widespread interest. This report describes the effects of small doses of alcohol (the highest being roughly

  3. UNIVERSITY OF COLORADO BOULDER Planetary science focuses on many aspects of

    E-print Network

    Mojzsis, Stephen J.

    UNIVERSITY OF COLORADO BOULDER Planetary science focuses on many aspects of planetary objects, from across the university. (CourtesyNASA/JPL) Planetary Science LASP scientists study geological- ated departments: · Geological sciences · Astrophysics and planetary sciences · Atmospheric and oceanic

  4. Taxonomy of the extrasolar planet.

    PubMed

    Plávalová, Eva

    2012-04-01

    When a star is described as a spectral class G2V, we know that the star is similar to our Sun. We know its approximate mass, temperature, age, and size. When working with an extrasolar planet database, it is very useful to have a taxonomy scale (classification) such as, for example, the Harvard classification for stars. The taxonomy has to be easily interpreted and present the most relevant information about extrasolar planets. I propose an extrasolar planet taxonomy scale with four parameters. The first parameter concerns the mass of an extrasolar planet in the form of units of the mass of other known planets, where M represents the mass of Mercury, E that of Earth, N Neptune, and J Jupiter. The second parameter is the planet's distance from its parent star (semimajor axis) described in a logarithm with base 10. The third parameter is the mean Dyson temperature of the extrasolar planet, for which I established four main temperature classes: F represents the Freezing class, W the Water class, G the Gaseous class, and R the Roasters class. I devised one additional class, however: P, the Pulsar class, which concerns extrasolar planets orbiting pulsar stars. The fourth parameter is eccentricity. If the attributes of the surface of the extrasolar planet are known, we are able to establish this additional parameter where t represents a terrestrial planet, g a gaseous planet, and i an ice planet. According to this taxonomy scale, for example, Earth is 1E0W0t, Neptune is 1N1.5F0i, and extrasolar planet 55 Cnc e is 9E-1.8R1. PMID:22506608

  5. Simulation of large scale motions and small scale structures in planetary atmospheres and oceans: From laboratory to space experiments on ISS

    NASA Astrophysics Data System (ADS)

    Egbers, Christoph; Futterer, Birgit; Zaussinger, Florian; Harlander, Uwe

    2014-05-01

    Baroclinic waves are responsible for the transport of heat and momentum in the oceans, in the Earth's atmosphere as well as in other planetary atmospheres. The talk will give an overview on possibilities to simulate such large scale as well as co-existing small scale structures with the help of well defined laboratory experiments like the baroclinic wave tank (annulus experiment). The analogy between the Earth's atmosphere and the rotating cylindrical annulus experiment only driven by rotation and differential heating between polar and equatorial regions is obvious. From the Gulf stream single vortices seperate from time to time. The same dynamics and the co-existence of small and large scale structures and their separation can be also observed in laboratory experiments as in the rotating cylindrical annulus experiment. This experiment represents the mid latitude dynamics quite well and is part as a central reference experiment in the German-wide DFG priority research programme ("METSTRÖM", SPP 1276) yielding as a benchmark for lot of different numerical methods. On the other hand, those laboratory experiments in cylindrical geometry are limited due to the fact, that the surface and real interaction between polar and equatorial region and their different dynamics can not be really studied. Therefore, I demonstrate how to use the very successful Geoflow I and Geoflow II space experiment hardware on ISS with future modifications for simulations of small and large scale planetary atmospheric motion in spherical geometry with differential heating between inner and outer spheres as well as between the polar and equatorial regions. References: Harlander, U., Wenzel, J., Wang, Y., Alexandrov, K. & Egbers, Ch., 2012, Simultaneous PIV- and thermography measurements of partially blocked flow in a heated rotating annulus, Exp. in Fluids, 52 (4), 1077-1087 Futterer, B., Krebs, A., Plesa, A.-C., Zaussinger, F., Hollerbach, R., Breuer, D. & Egbers, Ch., 2013, Sheet-like and plume-like thermal flow in a spherical convection experiment performed under microgravity, J. Fluid Mech., vol. 75, p 647-683

  6. Extrasolar Carbon Planets

    E-print Network

    Marc J. Kuchner; S. Seager

    2005-05-02

    We suggest that some extrasolar planets planets and low-mass white dwarf planets are especially good candidate members of this new class of planets, but these objects could also conceivably form around stars like the Sun. This planet-formation pathway requires only a factor of two local enhancement of the protoplanetary disk's C/O ratio above solar, a condition that pileups of carbonaceous grains may create in ordinary protoplanetary disks. Hot, Neptune-mass carbon planets should show a significant paucity of water vapor in their spectra compared to hot planets with solar abundances. Cooler, less massive carbon planets may show hydrocarbon-rich spectra and tar-covered surfaces. The high sublimation temperatures of diamond, SiC, and other carbon compounds could protect these planets from carbon depletion at high temperatures.

  7. The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)

    E-print Network

    M. Mayor; S. Udry; C. Lovis; F. Pepe; D. Queloz; W. Benz; J. -L. Bertaux; F. Bouchy; C. Mordasini; D. Segransan

    2008-06-27

    This paper reports on the detection of a planetary system with three Super-Earths orbiting HD40307. HD40307 is a K2V metal-deficient star at a distance of only 13 parsec, part of the HARPS GTO high-precision planet-search programme. The three planets on circular orbits have very low minimum masses of respectively 4.2, 6.9 and 9.2 Earth masses and periods of 4.3, 9.6 and 20.5 days. The planet with the shortest period is the lightest planet detected to-date orbiting a main sequence star. The detection of the correspondingly low amplitudes of the induced radial-velocity variations is completely secured by the 135 very high-quality HARPS observations illustrated by the radial-velocity residuals around the 3-Keplerian solution of only 0.85 m/s. Activity and bisector indicators exclude any significant perturbations of stellar intrinsic origin, which supports the planetary interpretation. Contrary to most planet-host stars, HD40307 has a marked sub-solar metallicity ([Fe/H]=-0.31), further supporting the already raised possibility that the occurrence of very light planets might show a different dependence on host star's metallicity compared to the population of gas giant planets. In addition to the 3 planets close to the central star, a small drift of the radial-velocity residuals reveals the presence of another companion in the system the nature of which is still unknown.

  8. Dynamical Evolution of Planetary Embryos

    NASA Technical Reports Server (NTRS)

    Wetherill, George W.

    2002-01-01

    During the past decade, progress has been made by relating the 'standard model' for the formation of planetary systems to computational and observational advances. A significant contribution to this has been provided by this grant. The consequence of this is that the rigor of the physical modeling has improved considerably. This has identified discrepancies between the predictions of the standard model and recent observations of extrasolar planets. In some cases, the discrepancies can be resolved by recognition of the stochastic nature of the planetary formation process, leading to variations in the final state of a planetary system. In other cases, it seems more likely that there are major deficiencies in the standard model, requiring our identifying variations to the model that are not so strongly constrained to our Solar System.

  9. NAAP ExtraSolar Planets 1/10 ExtraSolar Planets Student Guide

    E-print Network

    Farritor, Shane

    Name: NAAP ­ ExtraSolar Planets 1/10 ExtraSolar Planets ­ Student Guide Background Material, Center of Mass, and ExtraSolar Planet Detection. Question 1: Label the positions on the star's orbit be moving. #12;NAAP ­ ExtraSolar Planets 2/10 Part I: Exoplanet Radial Velocity Simulator Introduction Open

  10. Earth, Jupiter and Saturn as guides for extrasolar planets and brown dwarfs: a lightning climatology study

    NASA Astrophysics Data System (ADS)

    Hodosán, Gabriella; Asensio Torres, Rubén; Helling, Christiane; Vorgul, Irena

    2015-04-01

    Large-scale electrostatic discharges (i.e. lightning) have been observed in the Solar System. Apart from Earth there are direct detections from Jupiter and Saturn and indirect (only radio) detection from Uranus and Neptune. Recent observations made by the Venus Explorer revealed radio signals that may be related to lightning. Observations indicate that clouds form on extrasolar planets and brown dwarfs. The conditions in these clouds may be good for lightning to occur, which can be a main ionization process in these atmospheres (lightning in mineral clouds e.g.: Bailey et al. 2014, ApJ, 784, 43; Helling at al. 2013, ApJ, 767, 136; Helling et al. 2013, P&SS, 77, 152). In this study our aim is to compare lightning climatology from Earth, Jupiter and Saturn and use these statistics as a guide to study potential lightning on extrasolar planetary objects. Earth is a fair analogy for rocky or ocean planets while Jupiter and Saturn resemble giant planets and brown dwarfs. To give an estimate on the total lightning energy (or power) that can reach us from a particular extrasolar body, we need to know how much lightning can occur on the object globally. We will show the possibilities in the number and quality of the giant planet data sets, which may give a fine comparison of future observations of extrasolar giant gas planets and even brown dwarfs. Data were obtained from Lightning Imaging Sensor (LIS)/Optical Transient Detector (OTD) (e.g.: Cecil et al. 2014, Atmospheric Research, 135, 404), Sferics Timing and Ranging Network (STARNET) (e.g.: Morales Rodrigues et al. 2011, 2014, XIV and XV International Conference on Atmospheric Electricity) and World Wide Lightning Location Network (WWLLN) (e.g.: Hutchins et al. 2012, Radio Science, 47, RS6005), four major lightning detecting networks, which monitor lightning occurrence in the optical or radio range on Earth. We compare flash/stroke rates in space and time and use the data to refer to Earth as a transiting exoplanet. We analyze flash rates from a certain celestial direction (as if looked at Earth from outside the Solar System from a fixed location) to see how they vary as the planet orbits the star. The same comparison studies are conducted for Jupiter and Saturn from Galileo, Cassini and New Horizons data. The comparison of Earth-data shows the importance of the networks' detection efficiency (detected lightning over the total amount of lightning in percentages) and the location of the individual instruments of the networks. Characterizing exoplanets is a difficult task, however, there are planets in our Solar System, which are better studied. Here we show how using the knowledge we have on these planets is a key aspect of exoplanetary sciences. Acknowledgement: We thank Daniel J. Cecil from LIS/OTD, Carlos Augusto Morales Rodrigues from STARNET and Robert H. Holzworth from WWLLN who kindly helped us obtaining data from the lightning detecting networks. The authors wish to thank the World Wide Lightning Location Network (http://wwlln.net), a collaboration among over 50 universities and institutions, for providing the lightning location data used in this work.

  11. A Photometric Search for Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Howell, S. B.; Everett, M.; Davis, D. R.; Weidenschilling, S. J.; McGruder, C. H., III; Gelderman, R.

    2000-10-01

    We describe a new program for the photometric detection of extrasolar planets using the 1.3 m telescope on Kitt Peak, which will be operated by a consortium of universities headed by Western Kentucky Univ. and including South Carolina State Univ., Planetary Science Institute, Boston Univ., and UC-Berkeley (SSL). This approach will complement the existing, highly successful, spectroscopic searches. The theory of photometric transit detection has been discussed by a number of authors (e.g. Borucki & Summers 1984; Howell & Merline 1995; Howell et al. 1996) and shown to be well within the capabilities of both photomultiplier and CCD observations. The first photometric transit detection was recently accomplished for the spectroscopically discovered planet orbiting HD209458 (Henry et al. 2000). The detection of extrasolar planet transits requires high photometric precision rather than accuracy. The necessary photometric precision to detect Jupiter-, Neptune-, and Earth-sized planets in orbit around F-M dwarfs is 1%, 0.1% and 0.00001%, respectively. The required precision to observe transits by Jupiter-sized extrasolar planets is easily obtained with modern CCD detectors and the differential ensemble photometric techniques pioneered by Howell et al. (1988). The use of such a technique for ultra-high precision photometry has been described in numerous papers (Charbonneau et al. 2000, Howell 2000, plus many others). Everett and Howell recently used the Kitt Peak NOAO 0.9 m telescope with the wide-field MOSAIC camera to search for extrasolar planet transits. During this run, they achieved a photometric precision of 0.024% for this dataset. With the 1.3 m telescope, we expect to reach a photometric precision of ~ 0.01% (10-4 mag). Our consortium has recently begun to refurbish and automate the 1.3 m telescope, which will be known as the Remote-Controlled Telescope (RCT). The primary instrument will be a CCD camera with a SITe 2048 x 2048 CCD having pixel well depths of 363,000 electrons, read noise of 5 electrons, and quantum efficiency of 80% between 4000 and 7000 Angstroms. The camera will be able to image a 20 x 20 arcmin field of view with 0.6 arcsec/pixel to provide well-sampled PSFs. About 40% of the time on the RCT will be devoted to the search for extrasolar planets. Search observations are expected to begin in mid-2001. References: Borucki & Summers 1984, Icarus 58:121; Charbonneau et al. 2000, ApJ 529:L45; Henry et al. 2000, ApJ 529:L41; Howell 2000, Handbook of CCD Astronomy, Cambridge Univ. Press; Howell et al. 1996, AJ 112:1302; Howell & Merline 1995, Exp. Ast. 6:163; Howell et al. 1988, AJ 95:247.

  12. Dynamical Relaxation and Massive Extrasolar Planets

    E-print Network

    J. C. B. Papaloizou; Caroline Terquem

    2000-12-18

    Following the suggestion of Black (1997) that some massive extrasolar planets may be associated with the tail of the distribution of stellar companions, we investigate a scenario in which 5 < N < 100 planetary mass objects are assumed to form rapidly through a fragmentation process occuring in a disc or protostellar envelope on a scale of 100 au. These are assumed to have formed rapidly enough through gravitational instability or fragmentation that their orbits can undergo dynamical relaxation on a timescale of about 100 orbits. Under a wide range of initial conditions and assumptions the relaxation process ends with either (i) one potential 'hot Jupiter' plus up to two 'external' companions, i.e. planets orbiting near the outer edge of the initial distribution; (ii) one or two 'external' planets or even none at all; (iii) one planet on an orbit with a semi--major axis 10 to a 100 times smaller than the outer boundary radius of the inital distribution together with an 'external' companion. Most of the other objects are ejected and could contribute to a population of free floating planets. Apart from the potential 'hot Jupiters', all the bound objects are on highly eccentric orbits. We found that, apart from the close orbiters, the probability of ending up with a planet orbiting at a given distance from the central star increases with the distance. This is because of the tendency of the relaxation process to lead to collisions with the central star. We discuss the application of these results to some of the more massive extrasolar planets.

  13. Equations of State: Gateway to Planetary Origin and Evolution (Invited)

    NASA Astrophysics Data System (ADS)

    Melosh, J.

    2013-12-01

    Research over the past decades has shown that collisions between solid bodies govern many crucial phases of planetary origin and evolution. The accretion of the terrestrial planets was punctuated by planetary-scale impacts that generated deep magma oceans, ejected primary atmospheres and probably created the moons of Earth and Pluto. Several extrasolar planetary systems are filled with silicate vapor and condensed 'tektites', probably attesting to recent giant collisions. Even now, long after the solar system settled down from its violent birth, a large asteroid impact wiped out the dinosaurs, while other impacts may have played a role in the origin of life on Earth and perhaps Mars, while maintaining a steady exchange of small meteorites between the terrestrial planets and our moon. Most of these events are beyond the scale at which experiments are possible, so that our main research tool is computer simulation, constrained by the laws of physics and the behavior of materials during high-speed impact. Typical solar system impact velocities range from a few km/s in the outer solar system to 10s of km/s in the inner system. Extrasolar planetary systems expand that range to 100s of km/sec typical of the tightly clustered planetary systems now observed. Although computer codes themselves are currently reaching a high degree of sophistication, we still rely on experimental studies to determine the Equations of State (EoS) of materials critical for the correct simulation of impact processes. The recent expansion of the range of pressures available for study, from a few 100 GPa accessible with light gas guns up to a few TPa from current high energy accelerators now opens experimental access to the full velocity range of interest in our solar system. The results are a surprise: several groups in both the USA and Japan have found that silicates and even iron melt and vaporize much more easily in an impact than previously anticipated. The importance of these findings is illustrated by the impact origin of our Moon. Computer simulations that do not take account of the liquid/vapor phase change are unable to retain any material in orbit around the Earth after a planetary impact. A purely gaseous disk around the Earth is wracked by gravitational instabilities and soon collapses back onto the Earth. Only if the silicate EoS also includes a liquid phase can a disk remain stable long enough to condense into a moon. The implications of this new-found ease of vaporization have yet to be fully explored, but it seems clear that current ideas must undergo extensive revision. More melt and vapor production in impacts implies much larger volume changes of the impacted materials and hence more energetic post-impact expansion. EoSs are thus of vital importance to our understanding of the evolution of planetary systems. Computer simulations can (and must!) substitute for experiments for many aspects of large planetary collisions, but so far experiments are leading theory in accurate determination of equations of state. Yet, the fidelity of the computer simulations to Nature can be only as good as the accuracy of the inputs, making further experimental study of EoS a central task in the exploration and elucidation of our solar system and of planetary systems in general.

  14. An Astrometrically Measured Mass for Extrasolar Planet

    E-print Network

    An Astrometrically Measured Mass for Extrasolar Planet Gliese 876b By Michael McElwain Presented March 14, 2003 #12;Paper details A Mass For the Extrasolar Planet Gliese 876b Determined from Hubble Extrasolar Planets Radial Velocity Measurements Astrometry Photometry Interferometry Gravitational

  15. Characterising Extrasolar Planets in Reflected Light and Thermal Emission

    E-print Network

    Jean Schneider

    2002-10-29

    The physical bases of the detection and characterisation of extrasolar planets in the reflected light and thermal emission regimes are reviewed. They both have their advantages and disadvantages, including artefacts, in the determination of planet physical parameters (mass, size, albedo, surface and atmospheric conditions etc. A special attention is paid for Earth-like planets and new perspectives for these different aspects are also presented.

  16. Observational studies of transiting extrasolar planets (invited review)

    E-print Network

    Southworth, John

    2014-01-01

    The study of transiting extrasolar planets is only 15 years old, but has matured into a rich area of research. I review the observational aspects of this work, concentrating on the discovery of transits, the characterisation of planets from photometry and spectroscopy, the Homogeneous Studies project, starspots, orbital obliquities, and the atmospheric properties of the known planets. I begin with historical context and conclude with a glance to a future of TESS, CHEOPS, Gaia and PLATO.

  17. Spectrophotometry near the atmospheric cutoff of the strongest Bowen resonance fluorescence lines of O III in two planetary nebulae

    NASA Technical Reports Server (NTRS)

    O'Dell, C. R.; Opal, Chet B.

    1989-01-01

    Spectrophotometric results are presented for the stronger, well-resolved Bowen O III resonance fluorescence emission lines in the planetary nebulae 7027 and NGC 7662 down to and including the intrinsically strong line at 3133 A. These data are combined with results from the IUE atlas of spectra and similar results for the longer wavelength lines by Likkel and Aller (1986) to give the first full coverage of the Bowen lines. Good agreement is found with fluorescence theory for the primary cascade lines, except for the Likkel and Aller results. The efficiency of conversion of the exciting He II Ly-alpha into O III lines is determined, and values comparable to other planetary nebulae are found.

  18. The Microlensing Planet Finder: Completing the Census of Extrasolar Planets in the Milky Way

    E-print Network

    D. P. Bennett; I. Bond; E. Cheng; S. Friedman; P. Garnavich; B. Gaudi; R. Gilliland; A. Gould; M. Greenhouse; K. Griest; R. Kimble; J. Lunine; J. Mather; D. Minniti; M. Niedner; B. Paczynski; S. Peale; B. Rauscher; M. Rich; K. Sahu; D. Tenerelli; A. Udalski; N. Woolf; P. Yock

    2004-09-09

    The Microlensing Planet Finder (MPF) is a proposed Discovery mission that will complete the first census of extrasolar planets with sensitivity to planets like those in our own solar system. MPF will employ a 1.1m aperture telescope, which images a 1.3 sq. deg. field-of-view in the near-IR, in order to detect extrasolar planets with the gravitational microlensing effect. MPF's sensitivity extends down to planets of 0.1 Earth masses, and MPF can detect Earth-like planets at all separations from 0.7AU to infinity. MPF's extrasolar planet census will provide critical information needed to understand the formation and frequency of extra solar planetary systems similar to our own.

  19. Taxonomy of the extrasolar planet

    E-print Network

    Plávalová, E

    2011-01-01

    When a star is described as a spectral class G2V, we know that the star is similar to our Sun.We know its approximate mass, temperature, age and size. In our work with extrasolar planets database, it is very useful to have a taxonomy scale (classification), for example, like the Harvard classification for stars. This new taxonomy has to be comprehensible and present the important information about extrasolar planets. The important information of extrasolar planets are their mass, radius, period, density, eccentricity, temperature, and their distance from the parent star. There are too many parameters, that is, taxonomy with six parameters would be complicated and difficult to apply. We propose following the extrasolar planet taxonomy scale with only four parameters. The first parameter is the information about the mass of an extrasolar planet in the form of the units of the mass of other known planets, where M - Mercury, E - Earth, N - Neptune, and J - Jupiter. The second parameter is the distance from its pa...

  20. Origin theories for the eccentricities of extrasolar planets

    E-print Network

    Fathi Namouni

    2007-02-07

    Half the known extrasolar planets have orbital eccentricities in excess of 0.3. Such large eccentricities are surprising as it is thought that planets form in a protoplanetary disk on nearly circular orbits much like the current states of the solar system planets. Possible explanations for the large planetary eccentricities include the perturbations that accompany planet-planet scattering, the tidal interaction between the gas disk and the planets, Kozai's secular eccentricity cycles, the eccentricity excitation during planetary pair migration in mean motion resonance, the perturbations by stellar encounters, stellar-like relaxation that occurs if planets formed through gravitational instability, and the relative acceleration by the stellar jet system of the host star with respect to the companion. In this chapter, we comment on the relevance and characteristics of the various eccentricity origin theories.

  1. Planetary System Physics

    NASA Technical Reports Server (NTRS)

    Peale, S. J.

    2002-01-01

    Contents include a summary of publications followed by their abstracts titeled: 1. On microlensing rates and optical depth toward the Galactic center. 2. Newly discovered brown dwarfs not seen in microlensing timescale frequency distribution? 3. Origin and evolution of the natural satellites. 4. Probing the structure of the galaxy with microlensing. 5. Tides, Encyclopedia of Astronomy and Astrophysics. 6. The Puzzle of the Titan-Hyperion 4:3 Orbital Resonance. 7. On the Validity of the Coagulation Equation and the Nature of Runaway Growth. 8. Making Hyperion. 9. The MESSENGER mission to Mercury: Scientific objectives and implementation. 10. A Survey of Numerical Solutions to the Coagulation. 11. Probability of detecting a planetary companion during a microlensing event. 12. Dynamics and origin of the 2:l orbital resonances of the GJ876 planets. 13. Planetary Interior Structure Revealed by Spin Dynamics. 14. A primordial origin of the Laplace relation among the Galilean Satellites. 15. A procedure for determining the nature of Mercury's core. 16. Secular evolution of hierarchical planetary systems. 17. Tidally induced volcanism. 18. Extrasolar planets and mean motion resonances. 19. Comparison of a ground-based microlensing search for planets with a search from space.

  2. Extrasolar planet detection

    NASA Technical Reports Server (NTRS)

    Korechoff, R. P.; Diner, D. J.; Tubbs, E. F.; Gaiser, S. L.

    1994-01-01

    This paper discusses the concept of extrasolar planet detection using a large-aperture infared imaging telescope. Coronagraphic stellar apodization techniques are less efficient at infrared wavelengths compared to the visible, as a result of practical limitations on aperture dimensions, thus necessitating additional starlight suppression to make planet detection feasible in this spectral domain. We have been investigating the use of rotational shearing interferometry to provide up to three orders of magnitude of starlight suppression over broad spectral bandwidths. We present a theoretical analysis of the system performance requirements needed to make this a viable instrument for planet detection, including specifications on the interferometer design and telescope aperture characteristics. The concept of using rotational shearing interferometry as a wavefront error detector, thus providing a signal that can be used to adaptively correct the wavefront, will be discussed. We also present the status of laboratory studies of on-axis source suppression using a recently constructed rotational shearing interferometer that currently operates in the visible.

  3. An Investigation on the role of Planetary Boundary Layer Parameterization scheme on the performance of a hydrostatic atmospheric model over a Coastal Region

    NASA Astrophysics Data System (ADS)

    Anurose, J. T.; Subrahamanyam, Bala D.

    2012-07-01

    As part of the ocean/land-atmosphere interaction, more than half of the total kinetic energy is lost within the lowest part of atmosphere, often referred to as the planetary boundary layer (PBL). A comprehensive understanding of the energetics of this layer and turbulent processes responsible for dissipation of kinetic energy within the PBL require accurate estimation of sensible and latent heat flux and momentum flux. In numerical weather prediction (NWP) models, these quantities are estimated through different surface-layer and PBL parameterization schemes. This research article investigates different factors influencing the accuracy of a surface-layer parameterization scheme used in a hydrostatic high-resolution regional model (HRM) in the estimation of surface-layer turbulent fluxes of heat, moisture and momentum over the coastal regions of the Indian sub-continent. Results obtained from this sensitivity study of a parameterization scheme in HRM revealed the role of surface roughness length (z_{0}) in conjunction with the temperature difference between the underlying ground surface and atmosphere above (?T = T_{G} - T_{A}) in the estimated values of fluxes. For grid points over the land surface where z_{0} is treated as a constant throughout the model integration time, ?T showed relative dominance in the estimation of sensible heat flux. In contrast to this, estimation of sensible and latent heat flux over ocean were found to be equally sensitive on the method adopted for assigning the values of z_{0} and also on the magnitudes of ?T.

  4. CALIBRATION OF EQUILIBRIUM TIDE THEORY FOR EXTRASOLAR PLANET SYSTEMS

    SciTech Connect

    Hansen, Brad M. S., E-mail: hansen@astro.ucla.ed [Department of Physics and Astronomy and Institute of Geophysics and Planetary Physics, University of California Los Angeles, Los Angeles, CA 90095 (United States)

    2010-11-01

    We provide an 'effective theory' of tidal dissipation in extrasolar planet systems by empirically calibrating a model for the equilibrium tide. The model is valid to high order in eccentricity and parameterized by two constants of bulk dissipation-one for dissipation in the planet and one for dissipation in the host star. We are able to consistently describe the distribution of extrasolar planetary systems in terms of period, eccentricity, and mass (with a lower limit of a Saturn mass) with this simple model. Our model is consistent with the survival of short-period exoplanet systems, but not with the circularization period of equal mass stellar binaries, suggesting that the latter systems experience a higher level of dissipation than exoplanet host stars. Our model is also not consistent with the explanation of inflated planetary radii as resulting from tidal dissipation. The paucity of short-period planets around evolved A stars is explained as the result of enhanced tidal inspiral resulting from the increase in stellar radius with evolution.

  5. Charging of A Conductive Body In Relative Motion Within An Electrically Quiet Planetary Atmosphere: The Peasma Balloon Experiment

    Microsoft Academic Search

    M. Hamelin; J. J. Berthelier; L. Duvet; J. P. Lebreton

    2002-01-01

    The PEASMA (Perturbations Aéro-Electrodynamiques et Sonde Martienne) main sci- entific objective is to study the electrical charging of a conductive body in vertical motion in the atmosphere. During the COMAS-SOLA balloon flight experiment be- tween León and Taffala, Spain, 1995, a relaxation probe to measure the polar ionic conductivities in the atmosphere of Titan with the Huygens spacecraft was tested

  6. Planetary Science Advances with the International X-ray Observatory

    NASA Astrophysics Data System (ADS)

    Feigelson, Eric; Elsner, R.; Glassgold, A.; Guedel, M.; Montmerle, T.; Wargelin, B.; Wolk, S.

    2009-01-01

    X-ray studies of planetary systems are beginning to provide important insights inaccessible at other wavelengths. In our Solar System, charge exchange emission from solar particles is faint and variable with complex spectra, a situation well-matched to the planned International X-ray Observatory's high-throughput and high spectral resolution. Solar-type stars universally exhibit enhanced magnetic activity during their youth so that X-ray studies reveal the high-energy inputs to protoplanetary disks and planetary atmospheres. It is possible that X-ray illumination is a critical regulator to the formation of planets. This paper is based on the report of the Con-X ``Solar System, Planet Formation and Evolution'' Science Panel. (1) X-ray irradiation of protoplanetary disks can be probed with the 6.4 keV iron fluorescent line. Seen in a handful of protostars with Chandra and XMM, IXO will survey the line in hundreds of young stellar systems and will quantify the 10-30 keV emission stellar emission that can penetrate deep into the disk. In a few cases, X-ray `superflares' will permit disk reverberation mapping. Combined with infrared and submillimeter studies, IXO will establish the importance of X-ray illumination on protoplanetary disk physics and chemistry. (2) Planetary atmospheres show rapidly varying X-ray components from charge exchange of heavy solar wind ions, electron bremsstrahlung continuum from ion-neutral interactions, and scattering and fluorescence of solar X-ray emission. IXO will produce a movie of these effects in Jupiter as the planet rotates and responds to solar flare/CME events. IXO study of the remarkable Martian X-ray exosphere will constrain the evaporation of planetary atmospheres. Three additional science programs are outlined: study of charge exchange processes in cometary comae; spectroscopy of diffuse heliospheric charge exchange X-rays previously attributed to the hot local interstellar medium; and measurements of flaring in stars hosting extrasolar planets in the Habitable Zone to evaluate atmospheric evaporation.

  7. Transiting planetary system WASP7 (Southworth+, 2011)

    Microsoft Academic Search

    J. Southworth; M. Dominik; U. G. Jorgensen; S. Rahvar; C. Snodgrass; K. Alsubai; V. Bozza; P. Browne; M. Burgdorf; S. Calchi Novati; P. Dodds; S. Dreizler; F. Finet; T. Gerner; S. Hardis; K. Harpsoe; C. Hellier; T. C. Hinse; M. Hundertmark; N. Kains; E. Kerins; C. Liebig; L. Mancini; M. Mathiasen; M. T. Penny; S. Proft; D. Ricci; G. Scarpetta; S. Schaefer; F. Schoenebeck; J. Surdej

    2011-01-01

    A light curve of one transit of the extrasolar planetary system WASP-7 is presented. The data were obtained using the Danish 1.5m telescope and DFOSC camera at ESO La Silla in 2010, with substantial telescope defocussing in order to improve the photometric precision of the observations. A Johnson I filter and exposure times of 60s were used. (1 data file).

  8. Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations

    NASA Technical Reports Server (NTRS)

    Robinson, Tyler D.; Meadows, Victoria S.; Crisp, David; Deming, Drake; A'Hearn, Michael F.; Charbonneau, David; Livengood, Timothy A.; Seager, Sara; Barry, Richard; Hearty, Thomas; Hewagama, Tilak; Lisse, Carey M.; McFadden, Lucy; Wellnitz, Dennis D.

    2011-01-01

    The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole disk Earth model simulations used to better under- stand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute s Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model (Tinetti et al., 2006a,b). This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of approx.100 pixels on the visible disk, and four categories of water clouds, which were defined using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to the Earth s lightcurve, absolute brightness, and spectral data, with a root-mean-square error of typically less than 3% for the multiwavelength lightcurves, and residuals of approx.10% for the absolute brightness throughout the visible and NIR spectral range. We extend our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of approx.7%, and temperature errors of less than 1K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be used to simulate Earth s time dependent brightness and spectral properties for wavelengths from the far ultraviolet to the far infrared.brightness

  9. High Resolution UV Emission Cross Section for Analysis of Satellite Observations of Aurora and Dayglow of Planetary Atmosphere

    NASA Technical Reports Server (NTRS)

    Alvarez, J. M.

    1997-01-01

    A new generation of high resolution UV imaging spacecraft (Polar, Galileo, HST) are studying the airglow and aurora of the Earth and the Jovian planets. To keep pace with these technological improvements we have developed a laboratory program to provide electron collision cross sections of the major molecular planetary gases (H(sub 2), H, O, N(sub 2), CO(sub 2), SO(sub 2), O(sub 2), H(sub 2)O, and CO).

  10. Magnetospheric Radio Emission from Extrasolar Giant Planets: The Role of the Host Stars

    E-print Network

    Ian R. Stevens

    2004-10-25

    We present a new analysis of the expected magnetospheric radio emission from extrasolar giant planets for a distance limited sample of the nearest known extrasolar planets. Using recent results on the correlation between stellar X-ray flux and mass-loss rates from nearby stars, we estimate the expected mass-loss rates of the host stars of extrasolar planets that lie within 20pc of the Earth. We find that some of the host stars have mass-loss rates that are more than 100 times that of the Sun, and given the expected dependence of the planetary magnetospheric radio flux on stellar wind properties this has a very substantial effect. Using these results and extrapolations of the likely magnetic properties of the extrasolar planets we infer their likely radio properties. We compile a list of the most promising radio targets, and conclude that the planets orbiting Tau Bootes, Gliese 86, Upsilon Andromeda and HD1237 (as well as HD179949) are the most promising candidates, with expected flux levels that should be detectable in the near future with upcoming telescope arrays. The expected emission peak from these candidate radio emitting planets is typically \\~40-50 MHz. We also discuss a range of observational considerations for detecting extrasolar giant planets.

  11. PLANETARY CONSTRUCTION ZONES IN OCCULTATION: DISCOVERY OF AN EXTRASOLAR RING SYSTEM TRANSITING A YOUNG SUN-LIKE STAR AND FUTURE PROSPECTS FOR DETECTING ECLIPSES BY CIRCUMSECONDARY AND CIRCUMPLANETARY DISKS

    SciTech Connect

    Mamajek, Eric E.; Quillen, Alice C.; Pecaut, Mark J.; Moolekamp, Fred; Scott, Erin L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Kenworthy, Matthew A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Cameron, Andrew Collier; Parley, Neil R. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)

    2012-03-15

    The large relative sizes of circumstellar and circumplanetary disks imply that they might be seen in eclipse in stellar light curves. We estimate that a survey of {approx}10{sup 4} young ({approx}10 million year old) post-accretion pre-main-sequence stars monitored for {approx}10 years should yield at least a few deep eclipses from circumplanetary disks and disks surrounding low-mass companion stars. We present photometric and spectroscopic data for a pre-main-sequence K5 star (1SWASP J140747.93-394542.6 = ASAS J140748-3945.7), a newly discovered {approx}0.9 M{sub Sun} member of the {approx}16 Myr old Upper Centaurus-Lupus subgroup of Sco-Cen at a kinematic distance of 128 {+-} 13 pc. This star exhibited a remarkably long, deep, and complex eclipse event centered on 2007 April 29 (as discovered in Super Wide Angle Search for Planets (SuperWASP) photometry, and with portions of the dimming confirmed by All Sky Automated Survey (ASAS) data). At least five multi-day dimming events of >0.5 mag are identified, with a >3.3 mag deep eclipse bracketed by two pairs of {approx}1 mag eclipses symmetrically occurring {+-}12 days and {+-}26 days before and after. Hence, significant dimming of the star was taking place on and off over at least a {approx}54 day period in 2007, and a strong >1 mag dimming event occurring over a {approx}12 day span. We place a firm lower limit on the period of 850 days (i.e., the orbital radius of the eclipser must be >1.7 AU and orbital velocity must be <22 km s{sup -1}). The shape of the light curve is similar to the lopsided eclipses of the Be star EE Cep. We suspect that this new star is being eclipsed by a low-mass object orbited by a dense inner disk, further girded by at least three dusty rings of optical depths near unity. Between these rings are at least two annuli of near-zero optical depth (i.e., gaps), possibly cleared out by planets or moons, depending on the nature of the secondary. For possible periods in the range 2.33-200 yr, the estimated total ring mass is {approx}8-0.4 M{sub Moon} (if the rings have optical opacity similar to Saturn's rings), and the edge of the outermost detected ring has orbital radius {approx}0.4-0.09 AU. In the new era of time-domain astronomy opened by surveys like SuperWASP, ASAS, etc., and soon to be revolutionized by Large Synoptic Survey Telescope, discovering and characterizing eclipses by circumplanetary and circumsecondary disks will provide us with observational constraints on the conditions that spawn satellite systems around gas giant planets and planetary systems around stars.

  12. A much lower density for the transiting extrasolar planet WASP7

    Microsoft Academic Search

    J. Southworth; M. Dominik; U. G. Jørgensen; S. Rahvar; C. Snodgrass; K. Alsubai; V. Bozza; P. Browne; M. Burgdorf; S. Calchi Novati; P. Dodds; S. Dreizler; F. Finet; T. Gerner; S. Hardis; K. Harpsøe; C. Hellier; T. C. Hinse; M. Hundertmark; N. Kains; E. Kerins; C. Liebig; L. Mancini; M. Mathiasen; M. T. Penny; S. Proft; D. Ricci; K. Sahu; G. Scarpetta; S. Schäfer; F. Schönebeck; J. Surdej

    2011-01-01

    We present the first high-precision photometry of the transiting extrasolar planetary system WASP-7, obtained using telescope defocussing techniques and reaching a scatter of 0.68 mmag per point. We find that the transit depth is greater and that the host star is more evolved than previously thought. The planet has a significantly larger radius (1.330 ± 0.093 RJup versus ; RJup)

  13. Changing Face of the Extrasolar Giant Planet, HD 209458b

    E-print Network

    James Y-K. Cho; Kristen Menou; Brad Hansen; Sara Seager

    2003-03-12

    High-resolution atmospheric flow simulations of the tidally-locked extrasolar giant planet, HD 209458b, show large-scale spatio-temporal variability. This is in contrast to the simple, permanent day/night (i.e., hot/cold) picture. The planet's global circulation is characterized by a polar vortex in motion around each pole and a banded structure corresponding to ~3 broad zonal (east-west) jets. For very strong jets, the circulation-induced temperature difference between moving hot and cold regions can reach up to ~1000 K, suggesting that atmospheric variability could be observed in the planet's spectral and photometric signatures.

  14. Extrasolar Planets! Solar System Planets!

    E-print Network

    Nelson, Richard

    Extrasolar Planets! #12;Solar System Planets! #12;Small, rocky planets on the inside Large, gas-giant and ice-giant planets on the outside ! #12;Relative sizes of Solar System planets! #12;Relative sizes of Sun and planets The Sun is ~ 1000 times more massive than Jupiter Jupiter is ~ 300 times more massive

  15. Migration & Extra-solar Terrestrial Planets: Watering the Planets

    NASA Astrophysics Data System (ADS)

    Carter-Bond, Jade C.; O'Brien, David P.; Raymond, Sean N.

    2014-04-01

    A diverse range of terrestrial planet compositions is believed to exist within known extrasolar planetary systems, ranging from those that are relatively Earth-like to those that are highly unusual, dominated by species such as refractory elements (Al and Ca) or C (as pure C, TiC and SiC)(Bond et al. 2010b). However, all prior simulations have ignored the impact that giant planet migration during planetary accretion may have on the final terrestrial planetary composition. Here, we combined chemical equilibrium models of the disk around five known planetary host stars (Solar, HD4203, HD19994, HD213240 and Gl777) with dynamical models of terrestrial planet formation incorporating various degrees of giant planet migration. Giant planet migration is found to drastically impact terrestrial planet composition by 1) increasing the amount of Mg-silicate species present in the final body; and 2) dramatically increasing the efficiency and amount of water delivered to the terrestrial bodies during their formation process.

  16. Encyclopedia of Planetary Sciences

    NASA Astrophysics Data System (ADS)

    Shirley, J. H.; Fairbridge, R. W.

    1997-09-01

    Containing more than 450 entries by some 200 eminent contributors from all over the world, the Encyclopedia of Planetary Sciences is the first book to present this information in an authoritative yet approachable way. This encyclopedia deals with the atmospheres, surfaces and interiors of the planets and moons, and with the interplanetary environment of plasma fields, as well as with asteroids and meteorites. Processes such as accretion, differentiation, thermal evolution and impact cratering form another category of entries. Remote sensing techniques employed in investigation and exploration, such as magnetometry, photometry, and spectroscopy are described in separate articles. In addition the Encyclopedia chronicles the history of planetary science, including biographies of pioneering scientists, and detailed descriptions of all major lunar and planetary missions and programs. The Encyclopedia of Planetary Sciences is superbly illustrated throughout with over 450 line drawings, 180 black and white photographs, and 63 colour illustrations. It will be a key reference source for planetary scientists, astronomers, and workers in related disciplines such as geophysics, geology and the atmospheric sciences. Included in this book is a PC and Mac compatible CD-ROM containing over 200 relevant planetary and related images available from NASA. This CD-ROM has been specially compiled for the Encyclopedia by The United States National Space Science Data Center.

  17. Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z

    SciTech Connect

    Not Available

    1993-01-01

    Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, K-T Boundary Layer, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, planetary mantles, and space exploration. Separate abstracts have been prepared for articles from this report.

  18. The martian atmosphere in the region of Hellas basin as observed by the planetary Fourier spectrometer (PFS-MEX)

    NASA Astrophysics Data System (ADS)

    Grassi, D.; Formisano, V.; Forget, F.; Fiorenza, C.; Ignatiev, N. I.; Maturilli, A.; Zasova, L. V.

    2007-07-01

    This work presents a review of the observations acquired by the planetary Fourier spectrometer (PFS) in the region of the Hellas basin. Taking advantage of the high spectral resolution of PFS, the vertical air temperature profile can be investigated with a previously unexperienced vertical resolution. Extensive comparisons with the expectations of EMCD 4.0 database highlight moderate discrepancies, strongly dependant on season. Namely, the morning observations acquired around Ls=45° show a series of temperature deficiencies with recurrent spatial patterns in different observations, correlated with the topography profile. Trends of integrated dust loads as a function of the field of view (FOV) elevation are also described. Values are consistent with the retrieval hypothesis of a dust scale height equal to the gas one, even far from the season of main dust storms.

  19. Twenty-fourth Lunar and Planetary Science Conference. Part 1: A-F

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The topics covered include the following: petrology, petrography, meteoritic composition, planetary geology, atmospheric composition, astronomical spectroscopy, lunar geology, Mars (planet), Mars composition, Mars surface, volcanology, Mars volcanoes, Mars craters, lunar craters, mineralogy, mineral deposits, lithology, asteroids, impact melts, planetary composition, planetary atmospheres, planetary mapping, cosmic dust, photogeology, stratigraphy, lunar craters, lunar exploration, space exploration, geochronology, tectonics, atmospheric chemistry, astronomical models, and geochemistry.

  20. Theoretical Transmission Spectra During Extrasolar Giant Planet Transits

    E-print Network

    S. Seager; D. D. Sasselov

    2000-06-23

    The recent transit observation of HD 209458 b - an extrasolar planet orbiting a sun-like star - confirmed that it is a gas giant and determined that its orbital inclination is 85 degrees. This inclination makes possible investigations of the planet atmosphere. In this paper we discuss the planet transmission spectra during a transit. The basic tenet of the method is that the planet atmosphere absorption features will be superimposed on the stellar flux as the stellar flux passes through the planet atmosphere above the limb. The ratio of the planet's transparent atmosphere area to the star area is small, approximately 10^{-3} to 10^{-4}; for this method to work very strong planet spectral features are necessary. We use our models of close-in extrasolar giant planets to estimate promising absorption signatures: the alkali metal lines, in particular the Na I and K I resonance doublets, and the He I $2^3S$ - $2^3P$ triplet line at 1083.0 nm. If successful, observations will constrain the line-of-sight temperature, pressure, and density. The most important point is that observations will constrain the cloud depth, which in turn will distinguish between different atmosphere models. We also discuss the potential of this method for EGPs at different orbital distances and orbiting non-solar-type stars.

  1. Development of an Electrostatic Precipitator to Remove Martian Atmospheric Dust from ISRU Gas Intakes During Planetary Exploration Missions

    NASA Technical Reports Server (NTRS)

    Clements, J. Sidney; Thompson, Samuel M.; Cox, Nathan D.; Johansen, Michael R.; Williams, Blakeley S.; Hogue, Michael D.; Lowder, M. Loraine; Calle, Carlos I.

    2011-01-01

    Manned exploration missions to Mars will need dependable in situ resource utilization (ISRU) for the production of oxygen and other commodities. One of these resources is the Martian atmosphere itself, which is composed of carbon dioxide (95.3%), nitrogen (2.7%), argon (1.6%), oxygen (0.13%), carbon monoxide (0.07%), and water vapor (0.03%), as well as other trace gases. However, the Martian atmosphere also contains relatively large amounts of dust, uploaded by frequent dust devils and high Winds. To make this gas usable for oxygen extraction in specialized chambers requires the removal of most of the dust. An electrostatic precipitator (ESP) system is an obvious choice. But with an atmospheric pressure just one-hundredth of Earth's, electrical breakdown at low voltages makes the implementation of the electrostatic precipitator technology very challenging. Ion mobility, drag forces, dust particle charging, and migration velocity are also affected because the low gas pressure results in molecular mean free paths that are approximately one hundred times longer than those at Earth .atmospheric pressure. We report here on our efforts to develop this technology at the Kennedy Space Center, using gases with approximately the same composition as the Martian atmosphere in a vacuum chamber at 9 mbars, the atmospheric pressure on Mars. We also present I-V curves and large particle charging data for various versions of wire-cylinder and rod-cylinder geometry ESPs. Preliminary results suggest that use of an ESP for dust collection on Mars may be feasible, but further testing with Martian dust simulant is required.

  2. 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.

  3. The Long-Term Dynamical Evolution of Planetary Systems

    E-print Network

    Davies, Melvyn B; Armitage, Philip; Chambers, John; Ford, Eric; Morbidelli, Alessandro; Raymond, Sean N; Veras, Dimitri

    2013-01-01

    This chapter concerns the long-term dynamical evolution of planetary systems from both theoretical and observational perspectives. We begin by discussing the planet-planet interactions that take place within our own Solar System. We then describe such interactions in more tightly-packed planetary systems. As planet-planet interactions build up, some systems become dynamically unstable, leading to strong encounters and ultimately either ejections or collisions of planets. After discussing the basic physical processes involved, we consider how these interactions apply to extrasolar planetary systems and explore the constraints provided by observed systems. The presence of a residual planetesimal disc can lead to planetary migration and hence cause instabilities induced by resonance crossing; however, such discs can also stabilise planetary systems. The crowded birth environment of a planetary system can have a significant impact: close encounters and binary companions can act to destabilise systems, or sculpt t...

  4. Equatorial Planetary Waves and Their Signature in Atmospheric Variability KEVIN M. GRISE AND DAVID W. J. THOMPSON

    E-print Network

    in the troposphere and meridio- nally in the vicinity of the tropopause (e.g., Simmons and Hoskins 1978; Edmon et al W. J. THOMPSON Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado and 2) a Kelvin wave response to the east of the heating (e.g., Dima et al. 2005; Dima and Wallace 2007

  5. Asteroidal and planetary analysis

    NASA Technical Reports Server (NTRS)

    Hartmann, W. K.

    1975-01-01

    Photometric, spectrophotometric, and radiometric investigations of asteroids and planets are reported. Profiles of the planetary disk were used to study the physical structure of the Uranus atmosphere, and thermal and photographic properties of Saturn rings were theoretically modelled. Ground-based Mars observations were made for long-term comparison with Mariner 9 results.

  6. Mass Dependency of Isotope Fractionation of Gases Under Thermal Gradient and Its Possible Implications for Planetary Atmosphere Escaping Process

    NASA Technical Reports Server (NTRS)

    Sun, Tao; Niles, Paul; Bao, Huiming; Socki, Richard

    2014-01-01

    Physical processes that unmix elements/isotopes of gas molecules involve phase changes, diffusion (chemical or thermal), effusion and gravitational settling. Some of those play significant roles for the evolution of chemical and isotopic compositions of gases in planetary bodies which lead to better understanding of surface paleoclimatic conditions, e.g. gas bubbles in Antarctic ice, and planetary evolution, e.g. the solar-wind erosion induced gas escaping from exosphere on terrestrial planets.. A mass dependent relationship is always expected for the kinetic isotope fractionations during these simple physical processes, according to the kinetic theory of gases by Chapman, Enskog and others [3-5]. For O-bearing (O16, -O17, -O18) molecules the alpha O-17/ alpha O-18 is expected at 0.5 to 0.515, and for S-bearing (S32,-S33. -S34, -S36) molecules, the alpha S-33/ alpha S-34 is expected at 0.5 to 0.508, where alpha is the isotope fractionation factor associated with unmixing processes. Thus, one isotope pair is generally proxied to yield all the information for the physical history of the gases. However, we recently] reported the violation of mass law for isotope fractionation among isotope pairs of multiple isotope system during gas diffusion or convection under thermal gradient (Thermal Gradient Induced Non-Mass Dependent effect, TGI-NMD). The mechanism(s) that is responsible to such striking observation remains unanswered. In our past studies, we investigated polyatomic molecules, O2 and SF6, and we suggested that nuclear spin effect could be responsible to the observed NMD effect in a way of changing diffusion coefficients of certain molecules, owing to the fact of negligible delta S-36 anomaly for SF6.. On the other hand, our results also showed that for both diffusion and convection under thermal gradient, this NMD effect is increased by lower gas pressure, bigger temperature gradient and lower average temperature, which indicate that the nuclear spin effect may not be the significant contributor as the energies involved in the hyperfine effect are much smaller than those with molecular collisions, especially under convective conditions.

  7. Planetary transit surveys

    NASA Astrophysics Data System (ADS)

    Horne, K.

    2002-01-01

    I review the status and prospects of ground-based planetary transit surveys in the era before the Eddington and Kepler missions. Over 70 extra-solar planets have been found to date by high precision radial velocity searches, but so far only one of these exhibits planetary transits. This situation should dramatically reverse in the next few years as photometric searches begin to find large numbers of "Hot Jupiters" that transit in front of their host stars. I discuss and illustrate the methods being used to assess the planet catch of the Eddington mission. Scaling laws are derived to express the planet catch in terms of instrument parameters and planet type. More detailed Monte Carlo simulations yield simulated planet catalogs. Eddington's survey volume for Earth-analog planets extends to d ? 300 pc, and scales with star mass, planet radius and temperature as M-1/8r2T, strongly favouring large hot planets. The Eddington baseline design is likely to deliver only a handful of habitable Earths. The planet catch can be increased by design changes, subject of course to cost and feasibility constraints, to maximize the figure of merit ?d3 ~ ?(N At)3/2, where N is the number of co-aligned telescopes, A and ? are the effective pupil area and solid angle of each telescope, and t is the duration of the mission.

  8. THERMOCHEMICAL AND PHOTOCHEMICAL KINETICS IN COOLER HYDROGEN-DOMINATED EXTRASOLAR PLANETS: A METHANE-POOR GJ436b?

    SciTech Connect

    Line, Michael R.; Yung, Yuk L. [California Institute of Technology, Pasadena, CA 91106 (United States); Vasisht, Gautam; Chen, Pin [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Angerhausen, D., E-mail: mrl@gps.caltech.edu, E-mail: gv@s383.jpl.nasa.gov [Hamburger Sternwarte, Universitaet Hamburg, 21029 Hamburg (Germany)

    2011-09-01

    We introduce a thermochemical kinetics and photochemical model. We use high-temperature bidirectional reaction rates for important H, C, O, and N reactions (most importantly for CH{sub 4} to CO interconversion), allowing us to attain thermochemical equilibrium, deep in an atmosphere, purely kinetically. This allows the chemical modeling of an entire atmosphere, from deep-atmosphere thermochemical equilibrium to the photochemically dominated regime. We use our model to explore the atmospheric chemistry of cooler (T{sub eff} < 10{sup 3} K) extrasolar giant planets. In particular, we choose to model the nearby hot-Neptune GJ436b, the only planet in this temperature regime for which spectroscopic measurements and estimates of chemical abundances now exist. Recent Spitzer measurements with retrieval have shown that methane is driven strongly out of equilibrium and is deeply depleted on the day side of GJ436b, whereas quenched carbon monoxide is abundant. This is surprising because GJ436b is cooler than many of the heavily irradiated hot Jovians and thermally favorable for CH{sub 4}, and thus requires an efficient mechanism for destroying it. We include realistic estimates of ultraviolet flux from the parent dM star GJ436, to bound the direct photolysis and photosensitized depletion of CH{sub 4}. While our models indicate fairly rich disequilibrium conditions are likely in cooler exoplanets over a range of planetary metallicities, we are unable to generate the conditions for substantial CH{sub 4} destruction. One possibility is an anomalous source of abundant H atoms between 0.01 and 1 bars (which attack CH{sub 4}), but we cannot as yet identify an efficient means to produce these hot atoms.

  9. Anisotropic winds from close-in extra-solar planets

    E-print Network

    James M. Stone; Daniel Proga

    2008-12-13

    We present two-dimensional hydrodynamic models of thermally driven winds from highly irradiated, close-in extra-solar planets. We adopt a very simple treatment of the radiative heating processes at the base of the wind, and instead focus on the differences between the properties of outflows in multidimensions in comparison to spherically symmetric models computed with the same methods. For hot (T > 2 x 10^{4} K) or highly ionized gas, we find strong (supersonic) polar flows are formed above the planet surface which produce weak shocks and outflow on the night-side. In comparison to a spherically symmetric wind with the same parameters, the sonic surface on the day-side is much closer to the planet surface in multidimensions, and the total mass loss rate is reduced by almost a factor of four. We also compute the steady-state structure of interacting planetary and stellar winds. Both winds end in a termination shock, with a parabolic contact discontinuity which is draped over the planet separating the two shocked winds. The planetary wind termination shock and the sonic surface in the wind are well separated, so that the mass loss rate from the planet is essentially unaffected. However, the confinement of the planetary wind to the small volume bounded by the contact discontinuity greatly enhances the column density close to the planet, which might be important for the interpretation of observations of absorption lines formed by gas surrounding transiting planets.

  10. Delivery of Volatiles to Habitable Planets in Extrasolar Planetary Systems

    NASA Technical Reports Server (NTRS)

    Chambers, John E.; Kress, Monika E.; Bell, K. Robbins; Cash, Michele; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The Earth can support life because: (1) its orbit lies in the Sun's habitable zone', and (2) it contains enough volatile material (e.g. water and organics) for life to flourish. However, it seems likely that the Earth was drier when it formed because it accreted in a part of the Sun's protoplanetary nebula that was too hot for volatiles to condense. If this is correct, water and organics must have been delivered to the habitable zone, after dissipation of the solar nebula, from a 'wet zone' in the asteroid belt or the outer solar system, where the nebula was cool enough for volatiles to condense. Material from the wet zone would have been delivered to the Earth by Jupiter and Saturn. Gravitational perturbations from these giant planets made much of the wet zone unstable, scattering volatile-rich planetesimals and protoplanets across the Solar System. Some of these objects ultimately collided with the inner Planets which themselves lie in a stable part of the Solar System. Giant planets are now being discovered orbiting other sunlike stars. To date, these planets have orbits and masses very different from Jupiter and Saturn, such that few if any of these systems is likely to have terrestrial planets in the star's habitable zone. However, new discoveries are anticipated due to improved detector sensitivity and the increase in the timespan of observations. Here we present numerical experiments examining the range of giant-planet characteristics that: (1) allow stable terrestrial Planets to exist in a star's habitable zone, and (2) make a large part of the star's wet zone weakly unstable, thus delivering volatiles to the terrestrial planets over an extended period of time after the dissipation of the solar nebula.

  11. Space optics for studying extra-solar planetary systems

    NASA Technical Reports Server (NTRS)

    Brown, Robert A.

    1990-01-01

    The sharp imaging of telescopes in space will improve the ability to see faint objects near bright ones. One exciting application is the search for planets around other stars. However, because a planet is, at best, 10 exp 9 times fainter than a star in visible light, specialized optical systems are required. Using apodization to remove diffracted light, the limiting source of noise is the intensity of starlight scattered by mirror figure errors. Based on the prelaunch metrology of the HST mirrors, and considering only photonstatistics, months of integration would be needed for HST to detect Jupiter next to the sun at a distance of 5 pc. The integration times will be shorter for future telescopes in space with smoother mirrors and/or larger apertures.

  12. Climate and atmospheric modeling studies. Climate applications of Earth and planetary observations. Chemistry of Earth and environment

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The research conducted during the past year in the climate and atmospheric modeling programs concentrated on the development of appropriate atmospheric and upper ocean models, and preliminary applications of these models. Principal models are a one-dimensional radiative-convective model, a three-dimensional global climate model, and an upper ocean model. Principal applications have been the study of the impact of CO2, aerosols and the solar 'constant' on climate. Progress was made in the 3-D model development towards physically realistic treatment of these processes. In particular, a map of soil classifications on 1 degree x 1 degree resolution has been digitized, and soil properties have been assigned to each soil type. Using this information about soil properties, a method was developed to simulate the hydraulic behavior of soils of the world. This improved treatment of soil hydrology, together with the seasonally varying vegetation cover, will provide a more realistic study of the role of the terrestrial biota in climate change. A new version of the climate model was created which follows the isotopes of water and sources of water (or colored water) throughout the planet. Each isotope or colored water source is a fraction of the climate model's water. It participates in condensation and surface evaporation at different fractionation rates and is transported by the dynamics. A major benefit of this project has been to improve the programming techniques and physical simulation of the water vapor budget of the climate model.

  13. Observations of Extrasolar Planets Enabled by a Return to the Moon

    E-print Network

    P. R. McCullough

    2007-03-13

    Ambitious studies of Earth-like extrasolar planets are outlined in the context of an exploration initiative for a return to the Earth's Moon. Two mechanism for linearly polarizing light reflected from Earth-like planets are discussed: 1) Rayleigh-scattering from a planet's clear atmosphere, and 2) specular reflection from a planet's ocean. Both have physically simple and predictable polarized phase functions. The exoplanetary diurnal variation of the polarized light reflected from a ocean but not from a land surface has the potential to enable reconstruction of the continental boundaries on an Earth-like extrasolar planet. Digressions on the lunar exploration initiative also are presented.

  14. TIDAL EVOLUTION OF CLOSE-IN EXTRASOLAR PLANETS: HIGH STELLAR Q FROM NEW THEORETICAL MODELS

    SciTech Connect

    Penev, Kaloyan; Sasselov, Dimitar [Astronomy Department, Harvard University, 60 Garden St., M.S. 16, Cambridge, MA 02138 (United States)

    2011-04-10

    In recent years it has been shown that the tidal coupling between extrasolar planets and their stars could be an important mechanism leading to orbital evolution. Both the tides the planet raises on the star and vice versa are important and dissipation efficiencies ranging over four orders of magnitude are being used. In addition, the discovery of extrasolar planets extremely close to their stars has made it clear that the estimates of the tidal quality factor, Q, of the stars based on Jupiter and its satellite system and on main-sequence binary star observations are too low, resulting in lifetimes for the closest planets orders of magnitude smaller than their age. We argue that those estimates of the tidal dissipation efficiency are not applicable for stars with spin periods much longer than the extrasolar planets' orbital period. We address the problem by applying our own values for the dissipation efficiency of tides, based on our numerical simulations of externally perturbed volumes of stellar-like convection. The range of dissipation we find for main-sequence stars corresponds to stellar Q{sub *} of 10{sup 8} to 3 x 10{sup 9}. The derived orbit lifetimes are comparable to or much longer than the ages of the observed extrasolar planetary systems. The predicted orbital decay transit timing variations due to the tidal coupling are below the rate of ms yr{sup -1} for currently known systems, but within reach of an extended Kepler mission provided such objects are found in its field.

  15. arXiv:1204.0976v1[astro-ph.EP]4Apr2012 Using Satellites to Probe Extrasolar Planet Formation

    E-print Network

    Withers, Paul

    terrestrial planets (Mercury, Venus, Earth and Mars) or giant planets (Jupiter, Saturn, Uranus and NeptunearXiv:1204.0976v1[astro-ph.EP]4Apr2012 Using Satellites to Probe Extrasolar Planet Formation Paul characteristics, form only around giant planets. If true, the size and duration of a planetary system

  16. Planetary systems: Formation, evolution, and detection; Proceedings of the First International Conference, Pasadena, California, Dec. 8-10, 1992

    NASA Technical Reports Server (NTRS)

    Burke, Bernard F. (editor); Rahe, Jurgen H. (editor); Roettger, Elizabeth E. (editor)

    1994-01-01

    The papers in these proceedings relate to our present understanding about planetary system formation, the various methods and imaging techniques that may be used in searching for planets (or protoplanets) that are outside of the solar system (extrasolar planets), and the stars that seem most likely to have planetary systems, using recent observations. It was noted at the conference that, at this time, the only confirmed example of a planetary system is the one that surrounds our sun.

  17. Ethane in planetary and cometary atmospheres: Transmittance and fluorescence models of the ?7 band at 3.3 ?m

    NASA Astrophysics Data System (ADS)

    Villanueva, G. L.; Mumma, M. J.; Magee-Sauer, K.

    2011-08-01

    Ethane and other hydrocarbon gases have strong rovibrational transitions in the 3.3 ?m spectral region owing to C-H, CH2, and CH3 vibrational modes, making this spectral region prime for searching possible biomarker gases in extraterrestrial atmospheres (e.g., Mars, exoplanets) and organic molecules in comets. However, removing ethane spectral signatures from high-resolution terrestrial transmittance spectra has been imperfect because existing quantum mechanical models have been unable to reproduce the observed spectra with sufficient accuracy. To redress this problem, we constructed a line-by-line model for the ?7 band of ethane (C2H6) and applied it to compute telluric transmittances and cometary fluorescence efficiencies. Our model considers accurate spectral parameters, vibration-rotation interactions, and a functional characterization of the torsional hot band. We integrated the new band model into an advanced radiative transfer code for synthesizing the terrestrial atmosphere (LBLRTM), achieving excellent agreement with transmittance data recorded against Mars using three different instruments located in the Northern and Southern hemispheres. The retrieved ethane abundances demonstrate the strong hemispheric asymmetry noted in prior surveys of volatile hydrocarbons. We also retrieved sensitive limits for the abundance of ethane on Mars. The most critical validation of the model was obtained by comparing simulations of C2H6 fluorescent emission with spectra of three hydrocarbon-rich comets: C/2004 Q2 (Machholz), 8P/Tuttle, and C/2007 W1 (Boattini). The new model accurately describes the complex emission morphology of the ?7 band at low rotational temperatures and greatly increases the confidence of the retrieved production rates (and rotational temperatures) with respect to previously available fluorescence models.

  18. Ethane in Planetary and Cometary Atmospheres: Transmittance and Fluorescence Models of the nu7 Band at 3.3 Micrometers

    NASA Technical Reports Server (NTRS)

    Villanueva, G. L.; Mumma, M. J.; Magee-Sauer, K.

    2011-01-01

    Ethane and other hydrocarbon gases have strong rovibrational transitions in the 3.3 micron spectral region owing to C-H, CH2, and CH3 vibrational modes, making this spectral region prime for searching possible biomarker gases in extraterrestrial atmospheres (e.g., Mars, exoplanets) and organic molecules in comets. However, removing ethane spectral signatures from high-resolution terrestrial transmittance spectra has been imperfect because existing quantum mechanical models have been unable to reproduce the observed spectra with sufficient accuracy. To redress this problem, we constructed a line-by-line model for the n7 band of ethane (C2H6) and applied it to compute telluric transmittances and cometary fluorescence efficiencies. Our model considers accurate spectral parameters, vibration-rotation interactions, and a functional characterization of the torsional hot band. We integrated the new band model into an advanced radiative transfer code for synthesizing the terrestrial atmosphere (LBLRTM), achieving excellent agreement with transmittance data recorded against Mars using three different instruments located in the Northern and Southern hemispheres. The retrieved ethane abundances demonstrate the strong hemispheric asymmetry noted in prior surveys of volatile hydrocarbons. We also retrieved sensitive limits for the abundance of ethane on Mars. The most critical validation of the model was obtained by comparing simulations of C2H6 fluorescent emission with spectra of three hydrocarbon-rich comets: C/2004 Q2 (Machholz), 8P/Tuttle, and C/2007 W1 (Boattini). The new model accurately describes the complex emission morphology of the nu7 band at low rotational temperatures and greatly increases the confidence of the retrieved production rates (and rotational temperatures) with respect to previously available fluorescence models.

  19. Energy Balance Models and Planetary Dynamics

    NASA Technical Reports Server (NTRS)

    Domagal-Goldman, Shawn

    2012-01-01

    We know that planetary dynamics can have a significant affect on the climate of planets. Planetary dynamics dominate the glacial-interglacial periods on Earth, leaving a significant imprint on the geological record. They have also been demonstrated to have a driving influence on the climates of other planets in our solar system. We should therefore expect th.ere to be similar relationships on extrasolar planets. Here we describe a simple energy balance model that can predict the growth and thickness of glaciers, and their feedbacks on climate. We will also describe model changes that we have made to include planetary dynamics effects. This is the model we will use at the start of our collaboration to handle the influence of dynamics on climate.

  20. Changing Face of the Extrasolar Giant Planet, HD 209458b

    Microsoft Academic Search

    James Y-K; Kristen Menou; Bradley M. S. Hansen; Sara Seager

    2002-01-01

    High-resolution atmospheric flow simulations of the tidally-locked extrasolar\\u000agiant planet, HD 209458b, show large-scale spatio-temporal variability. This is\\u000ain contrast to the simple, permanent day\\/night (i.e., hot\\/cold) picture. The\\u000aplanet's global circulation is characterized by a polar vortex in motion around\\u000aeach pole and a banded structure corresponding to ~3 broad zonal (east-west)\\u000ajets. For very strong jets, the circulation-induced

  1. Predictions for the correlation between giant and terrestrial extrasolar planets in dynamically evolved systems

    E-print Network

    Dimitri Veras; Philip J. Armitage

    2006-04-04

    The large eccentricities of many giant extrasolar planets may represent the endpoint of gravitational scattering in initially more crowded systems. If so, the early evolution of the giant planets is likely to be more restrictive of terrestrial planet formation than would be inferred from the current, dynamically quiescent, configurations. Here, we study statistically the extent of the anti-correlation between giant planets and terrestrial planets expected in a scattering model. We use marginally stable systems of three giant planets, with a realistic range of planetary masses, as a simple model for the initial conditions prior to scattering, and show that after scattering the surviving planets reproduce well the known extrasolar planet eccentricities beyond a > 0.5 AU. By tracking the minimum periastron values of all planets during the evolution, we derive the distribution of orbital radii across which strong perturbations (from crossing orbits) are likely to affect low mass planet formation. We find that scattering affects inner planet formation at orbital separations less than 50% of the final periastron distance of the innermost massive planet in approximately 30% of the realizations, and can occasionally influence planet formation at orbital separations less than 20% of the final periastron distance of the innermost massive planet. The domain of influence of the scattering massive planets increases as the mass differential between the massive planets decreases. Observational study of the correlation between massive and terrestrial extrasolar planets in the same system has the potential to constrain the origin of planetary eccentricity.

  2. DARWIN - A Mission to Detect, and Search for Life on, Extrasolar Planets

    E-print Network

    C. S. Cockell; A. Leger; M. Fridlund; T. Herbst; L. Kaltenegger; O. Absil; C. Beichman; W. Benz; M. Blanc; A. Brack; A. Chelli; L. Colangeli; H. Cottin; V. Coude du Foresto; W. Danchi; D. Defrere; J. -W. den Herder; C. Eiroa; J. Greaves; T. Henning; K. Johnston; H. Jones; L. Labadie; H. Lammer; R. Launhardt; P. Lawson; O. P. Lay; J. -M. LeDuigou; R. Liseau; F. Malbet; S. R. Martin; D. Mawet; D. Mourard; C. Moutou; L. Mugnier; F. Paresce; A. Quirrenbach; Y. Rabbia; J. A. Raven; H. J. A. Rottgering; D. Rouan; N. Santos; F. Selsis; E. Serabyn; H. Shibai; M. Tamura; E. Thiebaut; F. Westall; White; J. Glenn

    2008-05-13

    The discovery of extra-solar planets is one of the greatest achievements of modern astronomy. The detection of planets with a wide range of masses demonstrates that extra-solar planets of low mass exist. In this paper we describe a mission, called Darwin, whose primary goal is the search for, and characterization of, terrestrial extrasolar planets and the search for life. Accomplishing the mission objectives will require collaborative science across disciplines including astrophysics, planetary sciences, chemistry and microbiology. Darwin is designed to detect and perform spectroscopic analysis of rocky planets similar to the Earth at mid-infrared wavelengths (6 - 20 micron), where an advantageous contrast ratio between star and planet occurs. The baseline mission lasts 5 years and consists of approximately 200 individual target stars. Among these, 25 to 50 planetary systems can be studied spectroscopically, searching for gases such as CO2, H2O, CH4 and O3. Many of the key technologies required for the construction of Darwin have already been demonstrated and the remainder are estimated to be mature in the near future. Darwin is a mission that will ignite intense interest in both the research community and the wider public.

  3. Sublimation-induced orbital perturbations of extrasolar active asteroids and comets: application to white dwarf systems

    E-print Network

    Veras, Dimitri; Gaensicke, Boris T

    2015-01-01

    The metal budgets in some white dwarf (WD) atmospheres reveal that volatile-rich circumstellar bodies must both exist in extrasolar systems and survive the giant branch phases of stellar evolution. The resulting behaviour of these active asteroids or comets which orbit WDs is not well-understood, but may be be strongly influenced by sublimation due to stellar radiation. Here we develop a model, generally applicable to any extrasolar system with a main sequence or WD star, that traces sublimation-induced orbital element changes in approximately km-sized extrasolar minor planets and comets traveling within hundreds of au. We derive evolution equations on orbital timescales and for arbitrarily steep power-law sublimation dependencies on distance, and place our model in a Solar system context. We also demonstrate the importance of coupling sublimation and general relativity, and the orbital consequences of outgassing in arbitrary directions. We prove that nongravitational accelerations alone cannot result in orbi...

  4. Atmosphere

    NSDL National Science Digital Library

    University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

    2003-01-01

    What is this atmosphere that surrounds the Earth? This instructional tutorial, part of an interactive laboratory series for grades 8-12, introduces students to the structure, effects, and components of the atmosphere. Here students investigate the composition of the atmosphere; effects of temperature, pressure, and ozone; the greenhouse effect; and how Earth compares with other planets. Interactive activities present students with opportunities to explore ideas and answer questions about the atmosphere, including its structure, the making of ozone, rocket launching, and measuring the atmosphere. Pop-up boxes provide additional information on topics such as dust, rain, and atmospheric composition. Students complete a final written review of six questions about the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

  5. The Twenty-Fifth Lunar and Planetary Science Conference. Part 2: H-O

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Various papers on lunar and planetary science are presented, covering such topics as: planetary geology, lunar geology, meteorites, shock loads, cometary collisions, planetary mapping, planetary atmospheres, chondrites, chondrules, planetary surfaces, impact craters, lava flow, achondrites, geochemistry, stratigraphy, micrometeorites, tectonics, mineralogy, petrology, geomorphology, and volcanology.

  6. "Weather" Variability Of Close-in Extrasolar Giant Planets

    E-print Network

    Kristen Menou; James Y-K. Cho; Sara Seager; Brad Hansen

    2003-03-12

    Shallow-water numerical simulations show that the atmospheric circulation of the close-in extrasolar giant planet (EGP) HD 209458b is characterized by moving circumpolar vortices and few bands/jets (in contrast with ~10 bands/jets and absence of polar vortices on cloud-top Jupiter and Saturn). The large spatial scales of moving circulation structures on HD 209458b may generate detectable variability of the planet's atmospheric signatures. In this Letter, we generalize these results to other close-in EGPs, by noting that shallow-water dynamics is essentially specified by the values of the Rossby (Ro) and Burger (Bu) dimensionless numbers. The range of likely values of Ro (~ 0.01 - 10) and Bu (~ 1 - 200) for the atmospheric flow of known close-in EGPs indicates that their circulation should be qualitatively similar to that of HD 209458b. This results mostly from the slow rotation of these tidally-synchronized planets.

  7. Detection and Characterization of Extrasolar Planets through Mean-Motion Resonances: Simulations of Hypothetical Debris Disks

    E-print Network

    Tabeshian, Maryam

    2015-01-01

    The gravitational influence of a planet on a nearby disk provides a powerful tool for detecting and studying extrasolar planetary systems. Here we demonstrate that gaps can be opened in dynamically cold debris disks at the mean-motion resonances of an orbiting planet. The gaps are opened away from the orbit of the planet itself, revealing that not all disk gaps need contain a planetary body. These gaps are large and deep enough to be detectable in resolved disk images for a wide range of reasonable disk-planet parameters, though we are not aware of any such gaps detected to date. The gap shape and size are diagnostic of the planet location, eccentricity and mass, and allow one to infer the existence of unseen planets, as well as many important parameters of both seen and unseen planets in these systems. We present expressions to allow the planetary mass to be calculated from observed gap width and location.

  8. A comprehensive survey of atmospheric quasi 3 day planetary-scale waves and their impacts on the day-to-day variations of the equatorial ionosphere

    NASA Astrophysics Data System (ADS)

    Liu, Guiping; England, Scott L.; Immel, Thomas J.; Frey, Harald U.; Mannucci, Anthony J.; Mitchell, Nicholas J.

    2015-04-01

    This study reports a comprehensive survey of quasi 3 day (2.5-4.5 day period) planetary-scale waves in the low-latitude mesosphere and lower thermosphere using the temperature observations from Thermosphere Ionosphere and Mesosphere Electric Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry throughout 2002-2012. Occurrences and properties of the waves, including the eastward propagating zonal wave numbers of 1-3 (E1-E3) and vertical wavelengths, are determined for each case. The impacts of these waves on the equatorial ionosphere are investigated by searching for the corresponding variations with the same periods and wave numbers in total electron content (TEC) from the concurrent observations of the ground-based GPS network. For a threshold amplitude of 4 K in temperature, a total of 300 waves are identified, of which there are 186 E1, 63 E2, and 51 E3 events. The mean amplitudes and vertical wavelengths of these waves are calculated to be about 7.9 K and 34 km for the E1, 5.7 K and 29 km for the E2, and 5.1 K and 27 km for the E3, having the standard deviations of 1.5 K and 6.5 km, 0.6 K and 5.6 km, and 0.5 K and 6.7 km. Occurrences of the E1 cases are not observed to depend on season, but the large-amplitude (>8 K) cases occur more often during solstices than at equinoxes. Similarly, the E2 and E3 cases are observed to occur most often in January-February and May-August. Among these waves, 199 cases (66%) are found to have the corresponding variations in the equatorial ionosphere with amplitudes ?4.2% relative to the mean TEC values (corresponding to 90th percentile). Most of these waves have long vertical wavelengths and large amplitudes (˜3 times more than short vertical wavelength and small-amplitude waves). Because no seasonal or solar cycle dependence on the frequency at which these waves have corresponding variations in the ionosphere at this TEC perturbation threshold is observed, we conclude that there is no seasonal and solar cycle dependence on the propagation of such waves from the mesopause region to higher altitudes. We also identify that only 28 cases (19%) of the E1 TEC variations do not correspond to any E1 waves, which is consistent with the hypothesis that E1 waves are the primary cause of E1 TEC variations. Conditions that are favorable for 3 day waves to create ionospheric variations are present approximately two thirds of the time. This study quantifies the importance and frequency of atmospheric quasi 3 day planetary-scale waves on the day-to-day variations of the equatorial ionosphere using a statistical rather than case study approach.

  9. Microlensing detection of extrasolar planets.

    PubMed

    Giannini, Emanuela; Lunine, Jonathan I

    2013-05-01

    We review the method of exoplanetary microlensing with a focus on two-body planetary lensing systems. The physical properties of planetary systems can be successfully measured by means of a deep analysis of lightcurves and high-resolution imaging of planetary systems, countering the concern that microlensing cannot determine planetary masses and orbital radii. Ground-based observers have had success in diagnosing properties of multi-planet systems from a few events, but space-based observations will be much more powerful and statistically more complete. Since microlensing is most sensitive to exoplanets beyond the snow line, whose statistics, in turn, allow for testing current planetary formation and evolution theories, we investigate the retrieval of semi-major axis density by a microlensing space-based survey with realistic parameters. Making use of a published statistical method for projected exoplanets quantities (Brown 2011), we find that one year of such a survey might distinguish between simple power-law semi-major axis densities. We conclude by briefly reviewing ground-based results hinting at a high abundance of free-floating planets and describing the potential contribution of space-based missions to understanding the frequency and mass distribution of these intriguing objects, which could help unveil the formation processes of planetary systems. PMID:23604071

  10. ON THE ANOMALOUS RADII OF THE TRANSITING EXTRASOLAR PLANETS

    SciTech Connect

    Laughlin, Gregory; Crismani, Matteo [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Adams, Fred C. [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States)

    2011-03-01

    We present a systematic evaluation of the agreement between the observed radii of 90 well-characterized transiting extrasolar giant planets and their corresponding model radii. Our model radii are drawn from previously published calculations of coreless giant planets that have attained their asymptotic radii, and which have been tabulated for a range of planet masses and equilibrium temperatures. (We report a two-dimensional polynomial fitting function that accurately represents the models.) As expected, the model radii provide a statistically significant improvement over a null hypothesis that the sizes of giant planets are completely independent of mass and effective temperature. As is well known, however, fiducial models provide an insufficient explanation; the planetary radius anomalies, R{identical_to}R{sub obs}-R{sub pred}, are strongly correlated with planetary equilibrium temperature. We find that the radius anomalies have a best-fit dependence, R{proportional_to}T{sub eff}{sup {alpha}}, with {alpha} = 1.4 {+-} 0.6. Incorporating this relation into the model radii leads to substantially less scatter in the radius correlation. The extra temperature dependence represents an important constraint on theoretical models for hot Jupiters. Using simple scaling arguments, we find support for the hypothesis of Batygin and Stevenson that this correlation can be attributed to a planetary heating mechanism that is mediated by magnetohydrodynamic coupling between the planetary magnetic field and near-surface flow that is accompanied by ohmic dissipation at adiabatic depth. Additionally, we find that the temperature dependence is likely too strong to admit kinetic heating as the primary source of anomalous energy generation within the majority of the observed transiting planets.

  11. The WKLMC empirical line lists (5852-7919 cm-1) for methane between 80 K and 296 K: "Final" lists for atmospheric and planetary applications

    NASA Astrophysics Data System (ADS)

    Campargue, A.; Leshchishina, O.; Wang, L.; Mondelain, D.; Kassi, S.

    2013-09-01

    The “final” version of the WKLMC (Wang, Kassi, Leshchishina, Mondelain, Campargue) empirical lists for methane at 80 K and 296 K is provided for the 5852-7919 cm-1 region. It was obtained by combining the WKMC list [A. Campargue, O. Leshchishina, L. Wang, D. Mondelain, S. Kassi, A.V. Nikitin, J. Quant. Spectrosc. Radiat. Transfer 113 (2012) 1855-1873] with new results obtained by differential absorption spectroscopy (DAS) in the 2?3 region (5852-6183 cm-1) [A. Campargue, O. Leshchishina, D. Mondelain, S. Kassi and A. Coustenis, J. Quant. Spectrosc. Radiat. Transfer 118 (2013) 49-59]. Two empirical lists for methane at 296 K and 80 K in “natural” abundance are provided for atmospheric and planetary applications, respectively. They include the isotopologue identification (12CH4, 13CH4 and CH3D) and the lower state energy level, Eemp, derived from the ratio of the line intensities measured at 296 K and 80 K. The 296 K list includes 55 262 absorption lines. The 80 K list is made applicable over a wider range of temperatures by including 30 282 lines observed only at 296 K, with corresponding lower state energy values chosen to make them below the detectivity limit at 80 K. Overall, the 80 K list includes 73 225 absorption lines. For the two temperatures, we provide the list in HITRAN format together with a file allowing for a line by line traceability of the listed spectroscopic parameters. The extrapolation capabilities of the 296 K list towards high temperature (˜1200 K) are discussed.

  12. Excitation of Orbital Eccentricities of Extrasolar Planets by Repeated Resonance Crossings

    E-print Network

    E. I. Chiang; D. Fischer; E. Thommes

    2001-12-05

    Orbits of known extrasolar planets that are located outside the tidal circularization regions of their parent stars are often substantially eccentric. By contrast, planetary orbits in our Solar System are approximately circular, reflecting planet formation within a nearly axisymmetric, circumsolar disk. We propose that orbital eccentricities may be generated by divergent orbital migration of two planets in a viscously accreting circumstellar disk. The migration is divergent in the sense that the ratio of the orbital period of the outer planet to that of the inner planet grows. As the period ratio diverges, the planets traverse, but are not captured into, a series of mean-motion resonances that amplify their orbital eccentricities in rough inverse proportion to their masses. Strong viscosity gradients in protoplanetary disks offer a way to reconcile the circular orbits of Solar System gas giants with the eccentric orbits of currently known extrasolar planets.

  13. Astronomers Report Discovery of New Extra-solar Planets: Four Reports

    NSDL National Science Digital Library

    Weinstock, Maia.

    2000-01-01

    If you are feeling alone in the universe, this news from 2000 of the search for new planets might inspire you. This account is from the popular space science Website, Space.com. It chronicles the latest detection of at least nine possible planetary bodies orbiting stars outside of our solar system. The text includes a discussion of how detection of wobble behavior is used in the search for extra-solar planets and plans for future planet hunts. This site also features links to Websites of the observatories involved in extra-solar planet detection, related Space.com stories, a diagram of Doppler shift due to stellar wobble and a table of the nine planet candidates's size and distance from Earth.

  14. Migration-induced architectures of planetary systems.

    PubMed

    Szuszkiewicz, Ewa; Podlewska-Gaca, Edyta

    2012-06-01

    The recent increase in number of known multi-planet systems gives a unique opportunity to study the processes responsible for planetary formation and evolution. Special attention is given to the occurrence of mean-motion resonances, because they carry important information about the history of the planetary systems. At the early stages of the evolution, when planets are still embedded in a gaseous disc, the tidal interactions between the disc and planets cause the planetary orbital migration. The convergent differential migration of two planets embedded in a gaseous disc may result in the capture into a mean-motion resonance. The orbital migration taking place during the early phases of the planetary system formation may play an important role in shaping stable planetary configurations. An understanding of this stage of the evolution will provide insight on the most frequently formed architectures, which in turn are relevant for determining the planet habitability. The aim of this paper is to present the observational properties of these planetary systems which contain confirmed or suspected resonant configurations. A complete list of known systems with such configurations is given. This list will be kept by us updated from now on and it will be a valuable reference for studying the dynamics of extrasolar systems and testing theoretical predictions concerned with the origin and the evolution of planets, which are the most plausible places for existence and development of life. PMID:22684330

  15. Planetary waves in rotating ionosphere

    SciTech Connect

    Khantadze, A. G.; Jandieri, V. G. [Tbilisi State University (Georgia); Jandieri, G. V. [Georgian Technical University (Georgia)

    2008-06-15

    The problem of propagation of ultralong planetary waves in the Earth's upper atmosphere is considered. A new exact solution to the MHD equations for the ionosphere is obtained in spherical coordinates with allowance for the geomagnetic field and Earth's rotation. A general dispersion relation is derived for planetary waves in the ionospheric E and F regions, and the characteristic features of their propagation in a weakly ionized ionospheric plasma are discussed.

  16. WATER FRACTIONS IN EXTRASOLAR PLANETESIMALS

    SciTech Connect

    Jura, M.; Xu, S., E-mail: jura@astro.ucla.edu, E-mail: sxu@astro.ucla.edu [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095-1562 (United States)

    2012-01-15

    With the goal of using externally polluted white dwarfs to investigate the water fractions of extrasolar planetesimals, we assemble from the literature a sample that we estimate to be more than 60% complete of DB white dwarfs warmer than 13,000 K, more luminous than 3 Multiplication-Sign 10{sup -3} L{sub Sun }, and within 80 pc of the Sun. When considering all the stars together, we find that the summed mass accretion rate of heavy atoms exceeds that of hydrogen by over a factor of 1000. If so, this sub-population of extrasolar asteroids treated as an ensemble has little water and is at least a factor of 20 drier than CI chondrites, the most primitive meteorites. Furthermore, while an apparent 'excess' of oxygen in a single DB can be interpreted as evidence that the accreted material originated in a water-rich parent body, we show that at least in some cases, there can be sufficient uncertainties in the time history of the accretion rate that such an argument may be ambiguous. Regardless of the difficulty associated with interpreting the results from an individual object, our analysis of the population of polluted DBs provides indirect observational support for the theoretical view that a snow line is important in disks where rocky planetesimals form.

  17. THE SURVIVAL OF WATER WITHIN EXTRASOLAR MINOR PLANETS

    SciTech Connect

    Jura, M.; Xu, S., E-mail: jura@astro.ucla.ed, E-mail: xsynju@gmail.co [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562 (United States)

    2010-11-15

    We compute that extrasolar minor planets can retain much of their internal H{sub 2}O during their host star's red giant evolution. The eventual accretion of a water-rich body or bodies onto a helium white dwarf might supply an observable amount of atmospheric hydrogen, as seems likely for GD 362. More generally, if hydrogen pollution in helium white dwarfs typically results from accretion of large parent bodies rather than interstellar gas as previously supposed, then H{sub 2}O probably constitutes at least 10% of the aggregate mass of extrasolar minor planets. One observational test of this possibility is to examine the atmospheres of externally polluted white dwarfs for oxygen in excess of that likely contributed by oxides such as SiO{sub 2}. The relatively high oxygen abundance previously reported in GD 378 can be explained plausibly but not uniquely by accretion of an H{sub 2}O-rich parent body or bodies. Future ultraviolet observations of white dwarf pollutions can serve to investigate the hypothesis that environments with liquid water that are suitable habitats for extremophiles are widespread in the Milky Way.

  18. Spectroscopic planetary detection

    NASA Technical Reports Server (NTRS)

    Deming, Drake

    1988-01-01

    One of the most promising methods for the detection of extra-solar planets is the spectroscopic method, where a small Doppler shift (approximately 10 meters/sec) in the spectrum of the parent star reveals the presence of planetary companions. However, solar-type stars may show spurious Doppler shifts due to surface activity. If these effects are periodic, as is the solar activity cycle, then they may masquerade as planetary companions. The goal of this investigation is to determine whether the solar cycle affects the Doppler stability of integrated sunlight. Observations of integrated sunlight are made in the near infrared (approximately 2 micrometer), using the Kitt Peak McMath Fourier transform spectrometer, with an N2O gas absorption cell for calibration. Researchers currently achieve an accuracy of approximately 5 meters/sec. Solar rotation velocities vary by plus or minus 2000 meters/sec across the solar disk, and imperfect optical integration of these velocities is the principal source of error. We have been monitoring the apparent velocity of integrated sunlight since 1983. They initially saw a decrease of approximately 30 meters/sec in the integrated light velocity from 1983 through 1985, but in 1987 to 1988 the integrated light velocity returned to its 1983 level. It is too early to say whether these changes are solar-cycle related. Although the FTS, unlike a slit spectrograph, has a large field of view, researchers are always looking for ways to improve the optical integration of the solar disk. They recently made an improvement in the method used to optically collimate the FTS, and this has reduced the error level, eliminating some systematic effects seen earlier.

  19. Stellar and planetary remnants in digital sky surveys

    NASA Astrophysics Data System (ADS)

    Girven, Jonathan

    Large scale digital sky surveys have produced an unprecedented volume of uniform data covering both vast proportions of the sky and a wide range of wavelength, from the ultraviolet to the near-infrared. The challenge facing astronomers today is how to use this multitude of information to extract trends, outliers and and rare objects. For example, a large sample of single white dwarf stars has the potential to probe the Galaxy through the luminosity function. The aim of this work was to study stellar and planetary remnants in these surveys. In the last few decades, it has been shown that a handful of white dwarfs have remnants of planetary systems around them, in the form of a dusty disc. These are currently providing the best constraints on the composition of extra-solar planetary systems. Finding significant numbers of dusty discs is only possible in large scale digital sky surveys. I ultilised the SDSS DR7 and colour-colour diagrams to and DA white dwarfs from optical photometry. This nearly doubled the number of spectroscopically confirmed DA white dwarfs in the SDSS compared with DR4 [Eisenstein et al., 2006], and introduced nearly 10; 000 photometric-only DA white dwarf candidates. I further cross-matched our white dwarf catalogue with UKIDSS LAS DR8 to carry out the currently largest and deepest untargeted search for low-mass companions to, and dust discs around, DA white dwarfs. Simultaneously, I analyzed Spitzer observations of 15 white dwarfs with metal-polluted atmospheres, all but one having helium-dominated atmospheres. Three of these stars were found to have an infrared excess consistent with a dusty disc. I used the total sample to estimate a typical disc lifetime of log[tdisc(yr)] = 5:6+1:1, which is compatible with the relatively large range estimated from different theoretical models. Subdwarf population synthesis models predicted a vast population of subdwarfs with F to K-type companions, produced in the effcient RLOF formation channel. I used a cross-match of ultraviolet, optical and infrared surveys to search for this unseen population. I select a complementary sample to those found from radial velocity surveys, offering direct tests of binary evolution pathways. Finally, I present a method to use common proper motion white dwarf pairs to constrain the initial-final mass relation, which is extremely uncertain at low masses. In the example I show, one of the stars is a magnetic white dwarf with B ' 6 MG, making this a rare and intriguing system from a magnetic white dwarf formation point of view.

  20. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry

    2014-03-01

    Preface: a personal view of planetary rings; 1. Introduction: the allure of the ringed planets; 2. Studies of planetary rings 1610-2013; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Uranus' rings and moons; 13. Neptune's partial rings; 14. Jupiter's ring-moon system after Galileo and New Horizons; 15. Ring photometry; 16. Dusty rings; 17. Concluding remarks; Afterword; Glossary; References; Index.