Phase Separation in Giant Planets: Inhomogeneous Evolution of Saturn
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Problems of Metallic Hydrogen and Room Temperature Superconductivity
EHPRG 2019 - Abstracts Problems of metallic hydrogen and room temperature superconductivity M.I. Eremets Max-Planck-Institut fur Chemie, Hahn-Meitner Weg 1, 55128 Mainz, Germany Keywords: high pressure, mrtallic hydrogen, room temperature superconductivity. *e-mail: [email protected] Metallic Hydrogen and Room-temperature hydrides at high pressures. We will present recent studies superconductivity (RTSC) are one the most challenging on YHx, CaHx, MgHx- other compounds which are and very long standing problems in solid-state physics. In considered as potential RTSCs. both, there is a significant progress over the recent years. We will consider various directions to explore high temperature conventional superconductivity at low and In 1935, Wigner and Huntington [1] predicted that ambient pressures. solid molecular hydrogen would dissociate at high pressure to form a metallic atomic solid at pressures Acknowledgments: This work was supported by the Max P370-500 GPa [1-3]. Besides the ultimate simplicity, Planck Society. atomic metallic hydrogen is attractive because of the 1. Wigner, E. and H.B. Huntington, On the possibility of predicted very high, room temperature for a metallic modification of hydrogen. J. Chem. Phys., 1935. 3: p. 764-770. superconductivity [4]. In another scenario, the 2. Pickard, C.J. and R.J. Needs, Structure of phase III of metallization first occurs in the 250-500 GPa pressure solid hydrogen. Nature Physics, 2007. 3. range in molecular hydrogen through overlapping of 3. McMinis, J., et al., Molecular to Atomic Phase electronic bands [5-8]. The calculations are not accurate Transition in Hydrogen under High Pressure. Phys. enough to predict which option is realized. -
Will Solid Hydrogen Ever Be a Metal?
news and views tures. The consequences of squeezing solid hydrogen are clearly a good deal more subtle Will solid hydrogen than at first thought, and it turns out that this, the ‘simplest’ of all molecular solids, has a rich and remarkably complex phase ever be a metal? diagram2,4,5 (Fig. 2). In phase I of solid hydrogen, the so-called orientationally disordered state, the individ- Peter P. Edwards and Friedrich Hensel ual molecules execute complete rotational At ultra-high pressures, liquid hydrogen becomes metallic. So should motion in addition to the usual molecular solid hydrogen, yet it stubbornly resists. A newly predicted vibrations. spontaneous asymmetry of molecules in the solid may be the reason. Below a temperature of about 120 K, solid hydrogen undergoes a transition at about n 1926 J. D. Bernal proposed that all The pressure-induced metallization of 1.5 million atmospheres to phase II, a state matter, when subjected to a high enough solid hydrogen can be viewed in terms of in which the constituent H2 molecules Ipressure, will inevitably become metallic electronic band theory. At low pressures the become ‘frozen’ in a random orientation in — that is, it will be permeated by a sea of solid is an infinite crystalline assembly of iso- the crystal. completely free electrons that conduct elec- lated H2 molecules, all weakly interacting. Phase III is undoubtedly the most tricity easily. The most enticing substance for The electrons are all bound to their mole- intriguing, because elemental hydrogen pressure-induced metallization is, in fact, cules, and need to be freed to conduct elec- remains in this state up to the highest pres- the lightest and supposedly the simplest of all tricity: in band-theory terms, we have a com- sures yet achieved, and still does not become the elements in the periodic table — hydro- pletely filled valence band separated by a very metallic. -
Saturn — from the Outside In
Saturn — From the Outside In Saturn — From the Outside In Questions, Answers, and Cool Things to Think About Discovering Saturn:The Real Lord of the Rings Saturn — From the Outside In Although no one has ever traveled ing from Saturn’s interior. As gases in from Saturn’s atmosphere to its core, Saturn’s interior warm up, they rise scientists do have an understanding until they reach a level where the tem- of what’s there, based on their knowl- perature is cold enough to freeze them edge of natural forces, chemistry, and into particles of solid ice. Icy ammonia mathematical models. If you were able forms the outermost layer of clouds, to go deep into Saturn, here’s what you which look yellow because ammonia re- trapped in the ammonia ice particles, First, you would enter Saturn’s up- add shades of brown and other col- per atmosphere, which has super-fast ors to the clouds. Methane and water winds. In fact, winds near Saturn’s freeze at higher temperatures, so they equator (the fat middle) can reach turn to ice farther down, below the am- speeds of 1,100 miles per hour. That is monia clouds. Hydrogen and helium rise almost four times as fast as the fast- even higher than the ammonia without est hurricane winds on Earth! These freezing at all. They remain gases above winds get their energy from heat ris- the cloud tops. Saturn — From the Outside In Warm gases are continually rising in Earth’s Layers Saturn’s atmosphere, while icy particles are continually falling back down to the lower depths, where they warm up, turn to gas and rise again. -
A Milestone in the Hunt for Metallic Hydrogen
News & views e-mails: [email protected]; Catterall, W. A. Sci. Signal. 3, ra70 (2010). Conventional techniques have been the [email protected] 11. Lemke, T. et al. J. Biol. Chem. 283, 34738–34744 (2008). bottleneck in applying extreme pressures to 12. Brandmayr, J. et al. J. Biol. Chem. 287, 22584–225924 1. Cannon, W. B. Bodily Changes in Pain, Hunger, Fear, and (2012). highly compressible materials such as hydro- Rage: An Account of Recent Researches into the Function 13. Fu, Y., Westenbroek, R. E., Scheuer, T. & Catterall, W. A. gen. Over the past few decades, research of Emotional Excitement (Appleton, 1915). Proc. Natl Acad. Sci. USA 110, 19621–19626 (2013). groups around the world have pushed the 2. Reuter, H. J. Physiol. (Lond.) 192, 479–492 (1967). 14. Rhee, H.-W. et al. Science 339, 1328–1331 (2013). 3. Liu, G. et al. Nature 577, 695–700 (2020). 15. Finlin, B. S., Crump, S. M., Satin, J. & Andres, D. A. boundaries of pressure generation. They have 4. Tsien, R. W., Giles, W. & Greengard, P. Nature New Biol. Proc. Natl Acad. Sci. USA 100, 14469–14474 (2003). also refined the tools and methods needed 240, 181–183 (1972). 16. Manning, J. R. et al. J. Am. Heart Assoc. 2, e000459 (2013). to accurately estimate pressures applied to a 5. Reuter, H. J. Physiol. (Lond.) 242, 429–451 (1974). 17. Yang, L. et al. J. Clin. Invest. 129, 647–658 (2019). 6. Osterrieder, W. et al. Nature 298, 576–578 (1982). 18. Bean, B. P., Nowycky, M. C. & Tsien, R. -
The University of Chicago Glimpses of Far Away
THE UNIVERSITY OF CHICAGO GLIMPSES OF FAR AWAY PLACES: INTENSIVE ATMOSPHERE CHARACTERIZATION OF EXTRASOLAR PLANETS A DISSERTATION SUBMITTED TO THE FACULTY OF THE DIVISION OF THE PHYSICAL SCIENCES IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF ASTRONOMY AND ASTROPHYSICS BY LAURA KREIDBERG CHICAGO, ILLINOIS AUGUST 2016 Copyright c 2016 by Laura Kreidberg All Rights Reserved Far away places with strange sounding names Far away over the sea Those far away places with strange sounding names Are calling, calling me. { Joan Whitney & Alex Kramer TABLE OF CONTENTS LIST OF FIGURES . vii LIST OF TABLES . ix ACKNOWLEDGMENTS . x ABSTRACT . xi 1 INTRODUCTION . 1 1.1 Exoplanets' Greatest Hits, 1995 - present . 1 1.2 Moving from Discovery to Characterization . 2 1.2.1 Clues from Planetary Atmospheres I: How Do Planets Form? . 2 1.2.2 Clues from Planetary Atmospheres II: What are Planets Like? . 3 1.2.3 Goals for This Work . 4 1.3 Overview of Atmosphere Characterization Techniques . 4 1.3.1 Transmission Spectroscopy . 5 1.3.2 Emission Spectroscopy . 5 1.4 Technical Breakthroughs Enabling Atmospheric Studies . 7 1.5 Chapter Summaries . 10 2 CLOUDS IN THE ATMOSPHERE OF THE SUPER-EARTH EXOPLANET GJ 1214b . 12 2.1 Introduction . 12 2.2 Observations and Data Reduction . 13 2.3 Implications for the Atmosphere . 14 2.4 Conclusions . 18 3 A PRECISE WATER ABUNDANCE MEASUREMENT FOR THE HOT JUPITER WASP-43b . 21 3.1 Introduction . 21 3.2 Observations and Data Reduction . 23 3.3 Analysis . 24 3.4 Results . 27 3.4.1 Constraints from the Emission Spectrum . -
Liquid Metallic Hydrogen and the Structure of Brown Dwarfs and Giant Planets W.B
CORE Metadata, citation and similar papers at core.ac.uk Provided by CERN Document Server Liquid metallic hydrogen and the structure of brown dwarfs and giant planets W.B. Hubbard, T. Guillot, J.I. Lunine Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 [email protected] A. Burrows Departments of Physics and Astronomy, University of Arizona, Tucson, AZ 85721 D. Saumon Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 M.S. Marley Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 R.S. Freedman Sterling Software, NASA Ames Research Center, Moffett Field, CA 94035 ABSTRACT Electron-degenerate, pressure-ionized hydrogen (usually referred to as metallic hydrogen) is the principal constituent of brown dwarfs, the long-sought objects which lie in the mass range between the lowest-mass stars (about eighty times the mass of Jupiter) and the giant planets. The thermodynamics and transport properties of metallic hydrogen are important for understanding the properties of these objects, which, unlike stars, continually and slowly cool from initial nondegenerate (gaseous) states. Within the last year, a brown dwarf (Gliese 229 B) has been detected and its spectrum observed and analyzed, and several examples of extrasolar giant planets have been discovered. The brown dwarf appears to have a mass of about forty to fifty Jupiter masses and is now too cool to be fusing hydrogen or deuterium, although we predict that it will have consumed all of its primordial deuterium. This paper reviews the current understanding of the interrelationship between its interior properties and its observed spectrum, and also discusses the current status of research on the structure of giant planets, both in our solar system and elsewhere. -
Alamos Scientific Laboratory of the University of California 10S ALAMOS, NEW MEXICO A7545
LA-61 72-MS Informal Report UC-34a Reporting Date: November 1975 Issued: January 1976 CIC-14 REPORT COLLECTION REPRODUCTION COPY Metallic Hydrogen: A Brief Technical Assessment by L. A. Gritzo N. H. Krikorian —L Contributors D. T. Vier A. T. Peaslee, Jr. r ) } alamos scientific laboratory of the university of California 10s ALAMOS, NEW MEXICO a7545 \ An Affirmative Action/Equal Opportunity Employer uNITEO STATES ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION CONTRACT W.7405.ENG. 36 In the interest of prompt distribution, this report was not edited by the Technical Information staff. This work was supported by the DoD Defense Advanced Research Projects Agency. The views and conclusions contained in this report are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the Defense Advanced Research Pro- jects Agency or of the United States Government. Printed in the United States of America. Available from Nationsl Technical Information Service U.S. Department of Commerce 6286 Port Royal Road Springfield. VA 22161 Price: Printed CopY $4.50 Microfiche $2.26 7%1, ,ePort w., Prep. red ,, . ●ccount ofwork ,p.a.,.,ed h k UnitedSW- Government. Neither the UqiwJSm- .or the U“itrd Stat” l?nersy Scwarch ..d Development Ad- ministration, nor any or their ●mpl.yccs. “or any of their con. tractors. ..bco.tr.clors, or their empl.>~, !n.kes .ny wmr..tv. ●xpress or implied, . ..s. nms .ny Irr.1 Ii.btlity or rcspywibility for the ●ccuracy, campleten”., or .sef.lnts. of an? mformattom apparatus, LWXIuct, w D,,JWSJ di~lo,~, or rrr.ramt. -
Saturn a Featured Article from Wikipedia, the Free Encyclopedia
Saturn A featured article from Wikipedia, the free encyclopedia This article is about the planet. For other uses, see Saturn (disambiguation). Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius about nine times that of Earth.[10][11] Although only one-eighth the average density of Earth, with its larger volume Saturn is just over 95 times more massive.[12][13][14] Saturn is named after the Ro- man god of agriculture; its astronomical symbol () represents the god's sickle. Saturn's interior is probably composed of a core of iron–nickel and rock (silicon and oxygen com- pounds). This core is surrounded by a deep layer of Saturn in natural color, photographed by Cassini in metallic hydrogen, an intermediate layer of liquid July 2008, approaching equinox. hydrogen and liquid helium, and finally outside the Frenkel line a gaseous outer layer.[15] Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. Electrical current within the metallic hydrogen layer is thought to give rise to Sat- urn's planetary magnetic field, which is weaker than Earth's, but has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's.[16] The outer atmosphere is generally bland and lacking in contrast, although long-lived fea- tures can appear. Wind speeds on Saturn can reach 1,800 km/h (500 m/s), higher than on Jupiter, but not as high as those on Neptune.[17] Saturn has a prominent ring system that consists of nine continuous main rings and three discontin- uous arcs and that is composed mostly of ice particles with a smaller amount of rocky debris and dust. -
REVIEW Doi:10.1038/Nature13782
REVIEW doi:10.1038/nature13782 Highlights in the study of exoplanet atmospheres Adam S. Burrows1 Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends. he modern era of exoplanet research started in 1995 with the Earth-like planet requires the ability to measure transit depths 100 times discovery of the planet 51 Pegasi b1, when astronomers detected more precisely. It was not long before many hundreds of gas giants were the periodic radial-velocity Doppler wobble in its star, 51 Peg, detected both in transit and by the radial-velocity method, the former Tinduced by the planet’s nearly circular orbit. With these data, and requiring modest equipment and the latter requiring larger telescopes knowledge of the star, the orbital period (P) and semi-major axis (a) with state-of-the-art spectrometers with which to measure the small could be derived, and the planet’s mass constrained. However, the incli- stellar wobbles. Both techniques favour close-in giants, so for many nation of the planet’s orbit was unknown and, therefore, only a lower years these objects dominated the bestiary of known exoplanets. -
The Spherical Bolometric Albedo of Planet Mercury
The Spherical Bolometric Albedo of Planet Mercury Anthony Mallama 14012 Lancaster Lane Bowie, MD, 20715, USA [email protected] 2017 March 7 1 Abstract Published reflectance data covering several different wavelength intervals has been combined and analyzed in order to determine the spherical bolometric albedo of Mercury. The resulting value of 0.088 +/- 0.003 spans wavelengths from 0 to 4 μm which includes over 99% of the solar flux. This bolometric result is greater than the value determined between 0.43 and 1.01 μm by Domingue et al. (2011, Planet. Space Sci., 59, 1853-1872). The difference is due to higher reflectivity at wavelengths beyond 1.01 μm. The average effective blackbody temperature of Mercury corresponding to the newly determined albedo is 436.3 K. This temperature takes into account the eccentricity of the planet’s orbit (Méndez and Rivera-Valetín. 2017. ApJL, 837, L1). Key words: Mercury, albedo 2 1. Introduction Reflected sunlight is an important aspect of planetary surface studies and it can be quantified in several ways. Mayorga et al. (2016) give a comprehensive set of definitions which are briefly summarized here. The geometric albedo represents sunlight reflected straight back in the direction from which it came. This geometry is referred to as zero phase angle or opposition. The phase curve is the amount of sunlight reflected as a function of the phase angle. The phase angle is defined as the angle between the Sun and the sensor as measured at the planet. The spherical albedo is the ratio of sunlight reflected in all directions to that which is incident on the body. -
Physical Characterization of NEA Large Super-Fast Rotator (436724) 2011 UW158
EPJ manuscript No. (will be inserted by the editor) Physical characterization of NEA Large Super-Fast Rotator (436724) 2011 UW158 A. Carbognani1, B. L. Gary2, J. Oey3, G. Baj4, and P. Bacci5 1 Astronomical Observatory of the Autonomous Region of Aosta Valley (OAVdA), Aosta - Italy 2 Hereford Arizona Observatory (Hereford, Cochise - U.S.A.) 3 Blue Mountains Observatory (Leura, Sydney - Australia) 4 Astronomical Station of Monteviasco (Monteviasco, Varese - Italy) 5 Astronomical Observatory of San Marcello Pistoiese (San Marcello Pistoiese, Pistoia - Italy) Received: date / Revised version: date Abstract. Asteroids of size larger than 0.15 km generally do not have periods smaller than 2.2 hours, a limit known as cohesionless spin-barrier. This barrier can be explained by the cohesionless rubble-pile structure model. There are few exceptions to this “rule”, called LSFRs (Large Super-Fast Rotators), as (455213) 2001 OE84, (335433) 2005 UW163 and 2011 XA3. The near-Earth asteroid (436724) 2011 UW158 was followed by an international team of optical and radar observers in 2015 during the flyby with Earth. It was discovered that this NEA is a new candidate LSFR. With the collected lightcurves from optical observations we are able to obtain the amplitude-phase relationship, sideral rotation period (PS = 0.610752 ± 0.000001 ◦ ◦ ◦ ◦ h), a unique spin axis solution with ecliptic coordinates λ = 290 ± 3 , β = 39 ± 2 and the asteroid 3D model. This model is in qualitative agreement with the results from radar observations. PACS. PACS-key discribing text of that key – PACS-key discribing text of that key 1 Introduction The near-Earth asteroid (436724) 2011 UW158 was discovered on 2011 Oct 25 by the Pan-STARRS 1 Observatory at Haleakala (Hawaii, USA). -
The H and G Magnitude System for Asteroids
Meetings The BAA Observers’ Workshops The H and G magnitude system for asteroids This article is based on a presentation given at the Observers’ Workshop held at the Open University in Milton Keynes on 2007 February 24. It can be viewed on the Asteroids & Remote Planets Section website at http://homepage.ntlworld.com/ roger.dymock/index.htm When you look at an asteroid through the eyepiece of a telescope or on a CCD image it is a rather unexciting point of light. However by analysing a number of images, information on the nature of the object can be gleaned. Frequent (say every minute or few min- Figure 2. The inclined orbit of (23) Thalia at opposition. utes) measurements of magnitude over periods of several hours can be used to generate a lightcurve. Analysis of such a lightcurve Absolute magnitude, H: the V-band magnitude of an asteroid if yields the period, shape and pole orientation of the object. it were 1 AU from the Earth and 1 AU from the Sun and fully Measurements of position (astrometry) can be used to calculate illuminated, i.e. at zero phase angle (actually a geometrically the orbit of the asteroid and thus its distance from the Earth and the impossible situation). H can be calculated from the equation Sun at the time of the observations. These distances must be known H = H(α) + 2.5log[(1−G)φ (α) + G φ (α)], where: in order for the absolute magnitude, H and the slope parameter, G 1 2 φ (α) = exp{−A (tan½ α)Bi} to be calculated (it is common for G to be given a nominal value of i i i = 1 or 2, A = 3.33, A = 1.87, B = 0.63 and B = 1.22 0.015).