DOCSLIB.ORG

The Local Bubble

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Local Bubble International Journal of Astronomy and Astrophysics, 2020, 10, 11-27 https://www.scirp.org/journal/ijaa ISSN Online: 2161-4725 ISSN Print: 2161-4717 On the Shape of the Local Bubble Lorenzo Zaninetti Physics Department, Turin, Italy How to cite this paper: Zaninetti, L. Abstract (2020) On the Shape of the Local Bubble. International Journal of Astronomy and The shape of the local bubble is modeled in the framework of the thin layer Astrophysics, 10, 11-27. approximation. The asymmetric shape of the local bubble is simulated by in- https://doi.org/10.4236/ijaa.2020.101002 troducing axial profiles for the density of the interstellar medium, such as Received: December 19, 2019 exponential, Gaussian, inverse square dependence and Navarro-Frenk-White. Accepted: February 3, 2020 The availability of some observed asymmetric profiles for the local bubble al- Published: February 6, 2020 lows us to match theory and observations via the observational percentage of Copyright © 2020 by author(s) and reliability. The model is compatible with the presence of radioisotopes on Scientific Research Publishing Inc. Earth. This work is licensed under the Creative Commons Attribution International Keywords License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ ISM: Bubbles, ISM: Clouds, Galaxy: Disk Open Access 1. Introduction The local bubble (LB) is a low-density region that surrounds the Sun. Because it is emitting in the X-rays, it is also called Local Hot Bubble (LHB), see [1] [2]. In the framework of thermal ionization equilibrium, the temperature is kT =(0.097 ± 0.013) keV or T =(1.1252 ±× 0.15) 106 K , see [3]. Recently, the following features of the LB have been discussed: the variations of the polariza- tion degree P, see [4]; and the polarization from the interstellar medium, due to irregular dust grains aligned with the magnetic field, see [5]. The presence of 60Fe in deep-sea measurements on Earth has triggered the study of the LB-sun inte- raction, see [6]. We now select some theoretical efforts that model the LB, as follows: the one-dimensional hydrocode with non-equilibrium ion evolution and dust, see [7] [8]; different tests to explain the FUSE data, see [9] [10]; the use of the parallel adaptive mesh refinement code EAF-PAMR, see [11]; hydrodynam- ical simulations of the LB, see [12]; and the study of the 3D structure of the magnetic field, see [13]. These models leave some questions unanswered, or only partially answered, as DOI: 10.4236/ijaa.2020.101002 Feb. 6, 2020 11 International Journal of Astronomy and Astrophysics L. Zaninetti follows: - Can we model the LB in the framework of the thin layer expansion of a shell in an interstellar medium (ISM) with symmetry in respect to the equatorial plane of the explosion? - Can we compare the data of the theoretical expansion, which is a function of the latitude, with the observed profiles of expansion of the LB? - What is the range of reliability of the Taylor expansion and Padé approxima- tion of the theoretical expansion in the framework of the thin layer? - Can we model the LB-Sun interaction? To answer these questions: Section 2 analyzes four profiles of density for the interstellar medium (ISM); Section 3 derives four equations of motion for the LB; and Section 4 discusses the results for the four equations of motion in terms of reliability of the model, it also introduces the interaction of many bubbles, dis- cusses the 60Fe-signature and explores the interaction of many bubbles. 2. The Density Profiles A point in Cartesian coordinates is characterized by x, y and z, and the position of the origin is the center of the LB. The same point in spherical coordinates is characterized by the radial distance r ∈∞[0, ], the polar angle θ ∈π[0, ] , and the azimuthal angle ϕ ∈π[0,2 ]. The following profiles are considered: exponential, Gaussian, inverse square dependence and Navarro-Frenk-White. 2.1. An Exponential Profile The density is assumed to have the following exponential dependence on z in Cartesian coordinates: ρ( zb; , ρρ00) = exp( − zb) , (1) where b represents the scale. In spherical coordinates, the density has the fol- lowing piecewise dependence ρ00if rr≤ ρρ(rr;00 ,, b ) = r cos(θ ) (2) ρ00exp−>if rr b which has a jump discontinuity at rr= 0 when θ > 0 . Given a solid angle ∆Ω , the total mass swept, M( rr;00 ,,, bθρ ,∆Ω) , in the interval [0,r] is M( rr;00 ,,, bθρ ,∆Ω) 222 b r cosθ++ 2rb cos θρ 2 b r cos(θ ) 1 ( ( ( )) ( ) ) 0 − =ρ 3 − b 00r 3 e (3) 3 (cos(θ )) 222 b r cosθ++ 2rb cos θρ 2 b r0 cos(θ ) ( 00( ( )) ( ) ) 0− + b ∆Ω 3 e (cos(θ )) DOI: 10.4236/ijaa.2020.101002 12 International Journal of Astronomy and Astrophysics L. Zaninetti 2.2. A Gaussian Profile The density is assumed to have the following Gaussian dependence on z in Car- tesian coordinates: 1 z2 − 2 b2 ρ( zb;, ρρ00) = e , (4) where b represents a parameter. In spherical coordinates, the density is ρ if rr≤ 00 ρρ= 1 z2 (rr;00 ,, b ) − (5) 2 b2 ρ00e if rr> and presents a jump discontinuity at rr= 0 when θ > 0 . The total mass swept, M( rr;00 ,,, bθρ) , in the interval [0,r] is M( rr;00 ,,, bθρ) 2 2 1 r (cos(θ )) 23− θ 13 rb 2 2 1b π 212 cos( )r =ρρr +− e b + erf (6) 00 023 3cos(θθ) 22cos( ) b ( ) ( ) 2 2 1 r0 (cos(θ )) 2 − 3 rb 2 1b π 212 cos(θ )r0 −ρ − 0 e 2 b + erf ∆Ω 0 23 cos(θθ) 22cos( ) b ( ) ( ) where erf ( x) is the error function, defined by 2 x 2 erf ( xt) = e−t d . (7) π ∫0 2.3. The Inverse Square Dependence The density is assumed to have the following dependence on z in Cartesian coordinates, −2 z ρ( zz;,00 ρρ) = 0 1 + . (8) z0 In this paper, we will adopt the following density profile in spherical coordinates ρ00if rr≤ −2 ρρ(rr;00 ,, b ) = r cos(θ ) (9) ρ001+>if rr z0 where the parameter z0 fixes the scale and ρ0 is the density at zz= 0 . The above density presents a jump discontinuity at rr= 0 when θ > 0 . The mass M 0 swept in the interval [0,r0 ] is 1 Mr=ρ 3 ∆Ω (10) 03 00 The total mass swept, M( rr;00 , z ,,θρ 0 ,∆Ω) , in the interval [0,r] is M( rr;00 , z ,,θρ 0 ,∆Ω) DOI: 10.4236/ijaa.2020.101002 13 International Journal of Astronomy and Astrophysics L. Zaninetti 243 1 ρρbr ρθ0brln( cos( ) + b) b =+− ρ r3 002 − 3 00 2 33 (cos(θ)) (cos( θ)) (cos( θθ)) (rb cos( ) + ) (11) 243 ρρbr ρθ00brln( cos( ) + b) b −00 + + 0 ∆Ω 22 33 θ θ θθ+ (cos( )) (cos( )) (cos( )) (rb0 cos( ) ) 2.4. Navarro-Frenk-White Profile The usual Navarro-Frenk-White (NFW) distribution has a dependence on r in spherical coordinates of the type 2 ρ rbr( + ) ρρ= 00 0 (rr;00 ,, b ) 2 , (12) rb( + r) where b represents the scale, see [14] for more details. The NFW profile along the axis z can be obtained by substituting r with rzcos(θ ) = 2 ρ rbr( + ) ρ ρθ= 00 0 (rr;00 ,, b , ) 2 , (13) rcos(θθ)( br+ cos( )) The piece-wise density is ρ00if rr≤ 2 ρ(rr; ,, b ρθ) = ρ00rbr( + 0) (14) 00 > 2 if rr0 rcos(θθ)( br+ cos( )) and has a jump discontinuity at rr= 0 when θ > 0 . The total mass swept, M( rr;00 ,, bρθ) , in the interval [0,r] is M( rr;00 ,,, bθρ ,∆Ω) 2 1 ρθ0((br+cos( )) ln( br + cos( θ)) ++ bbr)( 00) r = ρ r3 + = (15) 3 00 3 (cos(θθ)) (br+ cos( )) 2 ρθ0((br+ 0cos( )) ln( br +0 cos( θ)) ++ bbr)( 00) r − ∆Ω 3 θθ+ (cos( )) (br0 cos( )) 3. The Thin Layer Approximation The conservation of the momentum in spherical coordinates along the solid an- gle ∆Ω in the framework of the thin layer approximation states that M00( r) v 0= Mrv( ) , (16) where Mr00( ) and Mr( ) are the swept masses at r0 and r, and v0 and v are the velocities of the thin layer at r0 and r. This conservation law can be ex- dr pressed as a differential equation of the first order by inserting v = : dt dr Mr( ) = M( r) v. (17) dt 00 0 DOI: 10.4236/ijaa.2020.101002 14 International Journal of Astronomy and Astrophysics L. Zaninetti In the first phase from r = 0 to rr= 0 the density is constant and the explo- sion is symmetrical. In the second phase the density is function of the polar an- gle θ and therefore the shape of the advancing expansion is asymmetrical. The equation of motion for the four profiles is now derived. 3.1. Motion with a Constant Density In the case of constant density of the ISM, the analytical solution for the trajec- tory is 4 34 r( tt;,,0 r 0 v 0) = 4 rv 00( t −+ t 0) r 0, (18) and the velocity is 3 rv00 vtt( ;,,00 r v 0) = , (19) 3434 (4rv00( t−+ t 0) r 0) where r0 and v0 are the position and the velocity when tt= 0 , see [15] [16]. 3.2. Motion with an Exponential Profile In the case of an exponential density profile for the ISM, as given by Equation (2), the differential equation that models momentum conservation is 22 2 b rt cosθθ++ 2rtb cos 2 b cos(θ )rt( ) 1 (( ( )) ( ( )) ( ) ( ) ) − 3 − b r0 3 e 3 (cos(θ )) (20) 222 b r cosθθ++ 2rb cos 2 b r0 cos(θ ) ( 00( ( )) ( ) ) − d1 +=b 3 3 e.
Load more

Recommended publications
  • Upon Reconstructing the Origin of the Local Bubble and Loop I Via Radioisotopic Signatures on Earth
    galaxies Conference Report A Way Out of the Bubble Trouble?—Upon Reconstructing the Origin of the Local Bubble and Loop I via Radioisotopic Signatures on Earth Michael Mathias Schulreich 1,* ID , Dieter Breitschwerdt 1, Jenny Feige 1 and Christian Dettbarn 2 1 Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany; [email protected] (D.B.); [email protected] (J.F.) 2 Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12–14, 69120 Heidelberg, Germany; [email protected] * Correspondence: [email protected] Received: 31 January 2018; Accepted: 22 February 2018; Published: 25 February 2018 Abstract: Deep-sea archives all over the world show an enhanced concentration of the radionuclide 60Fe, isolated in layers dating from about 2.2 Myr ago. Since this comparatively long-lived isotope is not naturally produced on Earth, such an enhancement can only be attributed to extraterrestrial sources, particularly one or several nearby supernovae in the recent past. It has been speculated that these supernovae might have been involved in the formation of the Local Superbubble, our Galactic habitat. Here, we summarize our efforts in giving a quantitative evidence for this scenario. Besides analytical calculations, we present results from high-resolution hydrodynamical simulations of the Local Superbubble and its presumptive neighbor Loop I in different environments, including a self-consistently evolved supernova-driven interstellar medium. For the superbubble modeling, the time sequence and locations of the generating core-collapse supernova explosions are taken into account, which are derived from the mass spectrum of the perished members of certain, carefully preselected stellar moving groups.
    [Show full text]
  • Science Fiction Stories with Good Astronomy & Physics
    Science Fiction Stories with Good Astronomy & Physics: A Topical Index Compiled by Andrew Fraknoi (U. of San Francisco, Fromm Institute) Version 7 (2019) © copyright 2019 by Andrew Fraknoi. All rights reserved. Permission to use for any non-profit educational purpose, such as distribution in a classroom, is hereby granted. For any other use, please contact the author. (e-mail: fraknoi {at} fhda {dot} edu) This is a selective list of some short stories and novels that use reasonably accurate science and can be used for teaching or reinforcing astronomy or physics concepts. The titles of short stories are given in quotation marks; only short stories that have been published in book form or are available free on the Web are included. While one book source is given for each short story, note that some of the stories can be found in other collections as well. (See the Internet Speculative Fiction Database, cited at the end, for an easy way to find all the places a particular story has been published.) The author welcomes suggestions for additions to this list, especially if your favorite story with good science is left out. Gregory Benford Octavia Butler Geoff Landis J. Craig Wheeler TOPICS COVERED: Anti-matter Light & Radiation Solar System Archaeoastronomy Mars Space Flight Asteroids Mercury Space Travel Astronomers Meteorites Star Clusters Black Holes Moon Stars Comets Neptune Sun Cosmology Neutrinos Supernovae Dark Matter Neutron Stars Telescopes Exoplanets Physics, Particle Thermodynamics Galaxies Pluto Time Galaxy, The Quantum Mechanics Uranus Gravitational Lenses Quasars Venus Impacts Relativity, Special Interstellar Matter Saturn (and its Moons) Story Collections Jupiter (and its Moons) Science (in general) Life Elsewhere SETI Useful Websites 1 Anti-matter Davies, Paul Fireball.
    [Show full text]
  • Solar System
    Solar System From Wikipedia, the free encyclopedia This article is about the Sun and its planetary system. For other systems, see planetary system and star system. Solar System The Sun and planets of the Solar System. Sizes are to scale, distances and illumination are not. Age 4.568 billion years Location Local Interstellar Cloud, Local Bubble, Orion–Cygnus Arm, Milky Way System mass 1.0014 solar masses Nearest star Proxima Centauri (4.22 ly), Alpha Centauri system (4.37 ly) Nearest Alpha Centauri system (4.37 ly) knownplanetary system Planetary system Semi-major axis 30.10 AU (4.503 billion km) of outer planet (Neptune) Distance 50 AU to Kuiper cliff No. of stars 1 Sun No. of planets 8 Mercury, Venus, Earth, Mars,Jupiter, Saturn, Uranus, Neptune No. of Possibly several hundred.[1] known dwarf 5 (Ceres, Pluto, Haumea,Makemake, Eris) are currently planets recognized by the IAU No. of 422 (173 of planets[2] and 249 of minor planets[3]) known natural satellites No. of 628,057 (as of 2013-12-12)[4] known minor planets No. of 3,244 (as of 2013-12-12)[4] known comets No. of 19 identified round satellites Orbit about the Galactic Center Inclination 60.19° (ecliptic) ofinvariable plane to thegalactic plane Distance to 27,000±1,000 ly Galactic Center Orbital speed 220 km/s Orbital period 225–250 Myr Star-related properties Spectral type G2V [5] Frost line ≈5 AU Distance ≈120 AU toheliopause Hill ≈1–2 ly sphere radius The Solar System[a] is the Sun and the objects that orbit the Sun.
    [Show full text]
  • Solar Wind Charge Exchange Contributions to the Diffuse X-Ray Emission
    Solar Wind Charge Exchange Contributions to the Diffuse X-Ray Emission T. E. Cravensa, I. P. Robertsona, S. Snowdenb, K. Kuntzc, M. Collierb and M. Medvedeva aDept. of Physics and Astronomy, Malott Hall, 1251 Wescoe Hall Dr., University of Kansas, Lawrence, KS 66045 USA bNASA Goddard Space Flight Center, Greenbelt, MD, 20771 USA cDept. of Physics and Astronomy, Johns Hopkins University, 366 Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218 USA Abstract: Astrophysical x-ray emission is typically associated with hot collisional plasmas, such as the million degree gas residing in the solar corona or in supernova remnants. However, x-rays can also be produced in cooler gas by charge exchange collisions between highly-charged ions and neutral atoms or molecules. This mechanism produces soft x-ray emission plasma when the solar wind interacts with neutral gas in the solar system. Examples of such x-ray sources include comets, the terrestrial magnetosheath, and the heliosphere (where the solar wind interacts with incoming interstellar neutral gas). Heliospheric emission is thought to make a significant contribution to the observed soft x-ray background (SXRB). This emission needs to be better understood so that it can be distinguished from the SXRB emission associated with hot interstellar gas and the galactic halo. Keywords: x-rays, charge exchange, local bubble, heliosphere, solar wind PACS: 95.85 Nv; 96.60 Vg; 96.50 Ci; 96.50 Zc INTRODUCTION A key diagnostic tool for hot astrophysical plasmas is x-ray emission [e.g., 1]. Hot plasmas produce x-rays collisionally, both in the continuum from free-free and bound- free (e.g., electron-ion recombination) transitions and as line emission from highly ionized species (bound-bound transitions).
    [Show full text]
  • Physical Properties of the Local Interstellar Medium
    Space Sci Rev (2009) 143: 323–331 DOI 10.1007/s11214-008-9422-4 Physical Properties of the Local Interstellar Medium Seth Redfield Received: 3 April 2008 / Accepted: 23 July 2008 / Published online: 12 September 2008 © Springer Science+Business Media B.V. 2008 Abstract The observed properties of the local interstellar medium (LISM) have been facil- itated by a growing ultraviolet and optical database of high spectral resolution observations of interstellar absorption toward nearby stars. Such observations provide insight into the physical properties (e.g., temperature, turbulent velocity, and depletion onto dust grains) of the population of warm clouds (e.g., 7000 K) that reside within the Local Bubble. In particu- lar, I will focus on the dynamical properties of clouds within ∼15 pc of the Sun. This simple dynamical model addresses a wide range of issues, including, the location of the Sun as it pertains to the relationship between local interstellar clouds and the circumheliospheric in- terstellar medium (CHISM), the creation of small cold clouds inside the Local Bubble, and the association of interacting warm clouds and small-scale density fluctuations that cause interstellar scintillation. Local interstellar clouds that can be easily distinguished based on their dynamical properties also differentiate themselves by other physical properties. For example, the two nearest local clouds, the Local Interstellar Cloud (LIC) and the Galactic (G) Cloud, show distinct properties in temperature and depletion of iron and magnesium. The availability of large-scale observational surveys allows for studies of the global charac- teristics of our local interstellar environment, which will ultimately be necessary to address fundamental questions regarding the origins and evolution of the local interstellar medium.
    [Show full text]
  • Interstellar Heliospheric Probe/Heliospheric Boundary Explorer Mission—A Mission to the Outermost Boundaries of the Solar System
    Exp Astron (2009) 24:9–46 DOI 10.1007/s10686-008-9134-5 ORIGINAL ARTICLE Interstellar heliospheric probe/heliospheric boundary explorer mission—a mission to the outermost boundaries of the solar system Robert F. Wimmer-Schweingruber · Ralph McNutt · Nathan A. Schwadron · Priscilla C. Frisch · Mike Gruntman · Peter Wurz · Eino Valtonen · The IHP/HEX Team Received: 29 November 2007 / Accepted: 11 December 2008 / Published online: 10 March 2009 © Springer Science + Business Media B.V. 2009 Abstract The Sun, driving a supersonic solar wind, cuts out of the local interstellar medium a giant plasma bubble, the heliosphere. ESA, jointly with NASA, has had an important role in the development of our current under- standing of the Suns immediate neighborhood. Ulysses is the only spacecraft exploring the third, out-of-ecliptic dimension, while SOHO has allowed us to better understand the influence of the Sun and to image the glow of The IHP/HEX Team. See list at end of paper. R. F. Wimmer-Schweingruber (B) Institute for Experimental and Applied Physics, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 11, 24098 Kiel, Germany e-mail: [email protected] R. McNutt Applied Physics Laboratory, John’s Hopkins University, Laurel, MD, USA N. A. Schwadron Department of Astronomy, Boston University, Boston, MA, USA P. C. Frisch University of Chicago, Chicago, USA M. Gruntman University of Southern California, Los Angeles, USA P. Wurz Physikalisches Institut, University of Bern, Bern, Switzerland E. Valtonen University of Turku, Turku, Finland 10 Exp Astron (2009) 24:9–46 interstellar matter in the heliosphere. Voyager 1 has recently encountered the innermost boundary of this plasma bubble, the termination shock, and is returning exciting yet puzzling data of this remote region.
    [Show full text]
  • THE INTERSTELLAR MEDIUM (ISM) • Total Mass ~ 5 to 10 X 109 Solar Masses of About 5 – 10% of the Mass of the Milky Way Galaxy Interior to the SunS Orbit
    THE INTERSTELLAR MEDIUM (ISM) • Total mass ~ 5 to 10 x 109 solar masses of about 5 – 10% of the mass of the Milky Way Galaxy interior to the suns orbit • Average density overall about 0.5 atoms/cm3 or ~10-24 g cm-3, but large variations are seen The Interstellar Medium • Elemental Composition - essentially the same as the surfaces of Population I stars, but the gas may be ionized, neutral, or in molecules or dust. H I – neutral atomic hydrogen http://apod.nasa.gov/apod/astropix.html H2 - molecular hydrogen H II – ionized hydrogen He I – neutral helium Carbon, nitrogen, oxygen, dust, molecules, etc. THE INTERSTELLAR MEDIUM • Energy input – starlight (especially O and B), supernovae, cosmic rays • Cooling – line radiation from atoms and molecules and infrared radiation from dust • Largely concentrated (in our Galaxy) in the disk Evolution in the ISM of the Galaxy As a result the ISM is continually stirred, heated, and cooled – a dynamic environment, a bit like the Stellar winds earth’s atmosphere but more so because not gravitationally Planetary Nebulae confined Supernovae + Circulation And its composition evolves as the products of stellar evolution are mixed back in by stellar winds, supernovae, etc.: Stellar burial ground metal content The The 0.02 Stars Interstellar Big Medium Galaxy Bang Formation star formation White Dwarfs and Collisions Neutron stars Black holes of heavy elements fraction Total Star Formation 10 billion Time years The interstellar medium (hereafter ISM) was first discovered in 1904, with the observation of stationary calcium absorption lines superimposed on the Doppler shifting spectrum of a spectroscopic binary.
    [Show full text]
  • Probing the Local Bubble with Diffuse Interstellar Bands I
    A&A 585, A12 (2016) Astronomy DOI: 10.1051/0004-6361/201526656 & c ESO 2015 Astrophysics Probing the Local Bubble with diffuse interstellar bands I. Project overview and southern hemisphere survey Mandy Bailey1,2, Jacco Th. van Loon1, Amin Farhang3, Atefeh Javadi3, Habib G. Khosroshahi3, Peter J. Sarre4, and Keith T. Smith4,5, 1 Lennard-Jones Laboratories, Keele University, ST5 5BG, UK e-mail: [email protected] 2 Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, Liverpool L3 5RF, UK 3 School of Astronomy, Institute for Research in Fundamental Sciences (IPM), PO Box 19395-5746, Tehran, Iran 4 School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK 5 Royal Astronomical Society, Burlington House, Piccadilly, London W1J 0BQ, UK Received 2 June 2015 / Accepted 26 September 2015 ABSTRACT Context. The Sun traverses a low-density, hot entity called the Local Bubble. Despite its relevance to life on Earth, the conditions in the Local Bubble and its exact configuration are not very well known. Besides that, there is some unknown interstellar substance that causes a host of absorption bands across the optical spectrum, called diffuse interstellar bands (DIBs). Aims. We have started a project to chart the Local Bubble in a novel way and learn more about the carriers of the DIBs, by using DIBs as tracers of diffuse gas and environmental conditions. Methods. We conducted a high signal-to-noise spectroscopic survey of 670 nearby early-type stars to map DIB absorption in and around the Local Bubble. The project started with a southern hemisphere survey conducted at the European Southern Observatory’s New Technology Telescope and has since been extended to an all-sky survey using the Isaac Newton Telescope.
    [Show full text]
  • The Interstellar Medium Surrounding the Sun
    AA49CH07-Frisch ARI 5 August 2011 9:10 The Interstellar Medium Surrounding the Sun Priscilla C. Frisch,1 Seth Redfield,2 and Jonathan D. Slavin3 1Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637; email: [email protected] 2Astronomy Department, Wesleyan University, Middletown, Connecticut 06459; email: sredfi[email protected] 3Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, 02138; email: [email protected] Annu. Rev. Astron. Astrophys. 2011. 49:237–79 Keywords First published online as a Review in Advance on interstellar medium, heliosphere, interstellar dust, magnetic fields, May 31, 2011 interstellar abundances, exoplanets The Annual Review of Astronomy and Astrophysics is online at astro.annualreviews.org Abstract This article’s doi: The Solar System is embedded in a flow of low-density, warm, and partially 10.1146/annurev-astro-081710-102613 ionized interstellar material that has been sampled directly by in situ mea- Copyright c 2011 by Annual Reviews. surements of interstellar neutral gas and dust in the heliosphere. Absorption All rights reserved line data reveal that this interstellar gas is part of a larger cluster of local 0066-4146/11/0922-0237$20.00 interstellar clouds, which is spatially and kinematically divided into addi- by Wesleyan University - CT on 01/05/12. For personal use only. tional small-scale structures indicating ongoing interactions. An origin for the clouds that is related to star formation in the Scorpius-Centaurus OB association is suggested by the dynamic characteristics of the flow. Variable Annu. Rev. Astro. Astrophys. 2011.49:237-279. Downloaded from www.annualreviews.org depletions observed within the local interstellar medium (ISM) suggest an in- homogeneous Galactic environment, with shocks that destroy grains in some regions.
    [Show full text]
  • CHIPS): Studying the Interstellar Medium
    FS-2002-11-048-GSFC Cosmic Hot Interstellar Plasma Spectrometer (CHIPS): Studying the Interstellar Medium The Cosmic Hot Interstellar Plasma extreme ultraviolet region of the electromag- Spectrometer satellite is the first NASA netic spectrum, centered around 170 University-Class Explorer mission. The Angstroms (Å). This is a relatively unsurveyed CHIPS mission is studying the very hot, very band and the emissions at this wavelength low-density gas in the vast spaces between may contain important clues about the the stars in our local astronomical neighbor- process of cooling that takes place in the hood. The majority of the power radiated by Local Bubble of the Interstellar Medium. this hot gas occurs in the short-wavelength, In our galaxy alone, there are several hun- About 99% of the ISM is gas (hydrogen and dred billion stars. Nearby stars are easy to helium), the remaining one percent consists see, although most of the stars in the Milky of heavier elements and dust. The gas is Way are so distant that their combined light extremely dilute, with an average density of appears as a fuzzy band stretching across about 1 atom per cubic centimeter. The air we the sky on a clear night. Equally easy to see breathe is approximately 30 quintillion is the space between the stars - but how often (30,000,000,000,000,000,000) times more do you wonder about this space? Most of us dense than the ISM. Picture this: an "empty" have an idea that these vast spaces are coffee mug in the ISM would contain about empty, a perfect vacuum.
    [Show full text]
  • Local ISM 3D Distribution and Soft X-Ray Background Inferences on Nearby Hot Gas and the North Polar Spur
    A&A 566, A13 (2014) Astronomy DOI: 10.1051/0004-6361/201322942 & c ESO 2014 Astrophysics Local ISM 3D distribution and soft X-ray background Inferences on nearby hot gas and the North Polar Spur L. Puspitarini1,R.Lallement1,J.-L.Vergely2, and S. L. Snowden3 1 GEPI Observatoire de Paris, CNRS, Université Paris Diderot, place Jules Janssen, 92190 Meudon, France e-mail: [lucky.puspitarini;rosine.lallement]@obspm.fr 2 ACRI-ST, 260 route du Pin Montard, 06904 Sophia Antipolis, France e-mail: [email protected] 3 Code 662, NASA/Goddard Space Flight Center, Greenbelt MD 20771, USA e-mail: [email protected] Received 29 October 2013 / Accepted 27 January 2014 ABSTRACT Three-dimensional (3D) interstellar medium (ISM) maps can be used to locate not only interstellar (IS) clouds, but also IS bubbles between the clouds that are blown by stellar winds and supernovae, and that are filled by hot gas. To demonstrate this and to derive a clearer picture of the local ISM, we compare our recent 3D maps of the IS dust distribution to the ROSAT diffuse X-ray background maps after removing heliospheric emission. In the Galactic plane, there is a good correspondence between the locations and extents of the mapped nearby cavities and the soft (0.25 keV) background emission distribution, showing that most of these nearby cavities contribute to this soft X-ray emission. Assuming a constant dust-to-gas ratio and homogeneous 106 K hot gas filling the cavities, we modeled the 0.25 keV surface brightness in a simple way along the Galactic plane as seen from the Sun, taking the absorption by the mapped clouds into account.
    [Show full text]
  • The Solar System and Beyond Ten Years of ISSI Johannes Geiss & Bengt Hultqvist (Eds.)
    COVER-ISSI-SR-003 16-12-2005 12:56 Pagina 1 SR-003 ISSI Scientific Report SR-003 The Solar ofISSI Years Ten SystemandBeyond: The Solar System and Beyond Ten Years of ISSI Johannes Geiss & Bengt Hultqvist (Eds.) Contact: ESA Publications Division c/o ESTEC, PO Box 299, 2200 AG Noordwijk, The Netherlands Tel. (31) 71 565 3400 - Fax (31) 71 565 5433 colofon 16-12-2005 12:54 Pagina i i SR-003 June 2005 The Solar System and Beyond Ten Years of ISSI Editors Johannes Geiss and Bengt Hultqvist The Solar System and Beyond: Ten Years of ISSI colofon 16-12-2005 12:54 Pagina ii ii J. Geiss & B. Hultqvist Cover: Earth rising above the lunar horizon as seen by the Apollo 8 crew - Frank Borman, James Lovell and William Anders - when orbiting the Moon in December 1968 (Photo: NASA/Apollo 8 crew) The International Space Science Institute is organized as a foundation under Swiss law. It is funded through recurrent contributions from the European Space Agency, the Swiss Confederation, the Swiss National Science Foundation, and the University of Bern. Published for: The International Space Science Institute Hallerstrasse 6, CH-3012 Bern, Switzerland by: ESA Publications Division ESTEC, PO Box 299, 2200 AG Noordwijk, The Netherlands Publication Manager: Bruce Battrick Layout: Jules Perel Copyright: © 2005 ISSI/ESA ISBN: 1608-280X Price: 30 Euros Contents 16-12-2005 11:27 Pagina iii iii Contents R.-M. Bonnet Foreword . v PART A J. Geiss and B. Hultqvist Introduction . 3 R. Lallement The Need for Interdisciplinarity . 5 L.A. Fisk The Exploration of the Heliosphere in Three Dimensions with Ulysses .
    [Show full text]