Imaging Exoplanets
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The Hunt for Exomoons with Kepler (Hek)
The Astrophysical Journal, 777:134 (17pp), 2013 November 10 doi:10.1088/0004-637X/777/2/134 C 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE HUNT FOR EXOMOONS WITH KEPLER (HEK). III. THE FIRST SEARCH FOR AN EXOMOON AROUND A HABITABLE-ZONE PLANET∗ D. M. Kipping1,6, D. Forgan2, J. Hartman3, D. Nesvorny´ 4,G.A.´ Bakos3, A. Schmitt7, and L. Buchhave5 1 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA; [email protected] 2 Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK 3 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 05844, USA 4 Department of Space Studies, Southwest Research Institute, Boulder, CO 80302, USA 5 Niels Bohr Institute, Copenhagen University, Denmark Received 2013 June 4; accepted 2013 September 8; published 2013 October 22 ABSTRACT Kepler-22b is the first transiting planet to have been detected in the habitable zone of its host star. At 2.4 R⊕, Kepler-22b is too large to be considered an Earth analog, but should the planet host a moon large enough to maintain an atmosphere, then the Kepler-22 system may yet possess a telluric world. Aside from being within the habitable zone, the target is attractive due to the availability of previously measured precise radial velocities and low intrinsic photometric noise, which has also enabled asteroseismology studies of the star. For these reasons, Kepler-22b was selected as a target-of-opportunity by the “Hunt for Exomoons with Kepler” (HEK) project. In this work, we conduct a photodynamical search for an exomoon around Kepler-22b leveraging the transits, radial velocities, and asteroseismology plus several new tools developed by the HEK project to improve exomoon searches. -
2018 Workshop on Autonomy for Future NASA Science Missions
NOTE: This document was prepared by a team that participated in the 2018 Workshop on Autonomy for Future NASA Science Missions. It is for informational purposes to inform discussions regarding the use of autonomy in notional science missions and does not specify Agency plans or directives. 2018 Workshop on Autonomy for Future NASA Science Missions: Ocean Worlds Design Reference Mission Reports Table of Contents Introduction .................................................................................................................................... 2 The Ocean Worlds Design Reference Mission Report .................................................................... 3 Ocean Worlds Design Reference Mission Report Summary ........................................................ 20 1 NOTE: This document was prepared by a team that participated in the 2018 Workshop on Autonomy for Future NASA Science Missions. It is for informational purposes to inform discussions regarding the use of autonomy in notional science missions and does not specify Agency plans or directives. Introduction Autonomy is changing our world; commercial enterprises and academic institutions are developing and deploying drones, robots, self-driving vehicles and other autonomous capabilities to great effect here on Earth. Autonomous technologies will also play a critical and enabling role in future NASA science missions, and the Agency requires a specific strategy to leverage these advances and infuse them into its missions. To address this need, NASA sponsored the -
Breakthrough Propulsion Study Assessing Interstellar Flight Challenges and Prospects
Breakthrough Propulsion Study Assessing Interstellar Flight Challenges and Prospects NASA Grant No. NNX17AE81G First Year Report Prepared by: Marc G. Millis, Jeff Greason, Rhonda Stevenson Tau Zero Foundation Business Office: 1053 East Third Avenue Broomfield, CO 80020 Prepared for: NASA Headquarters, Space Technology Mission Directorate (STMD) and NASA Innovative Advanced Concepts (NIAC) Washington, DC 20546 June 2018 Millis 2018 Grant NNX17AE81G_for_CR.docx pg 1 of 69 ABSTRACT Progress toward developing an evaluation process for interstellar propulsion and power options is described. The goal is to contrast the challenges, mission choices, and emerging prospects for propulsion and power, to identify which prospects might be more advantageous and under what circumstances, and to identify which technology details might have greater impacts. Unlike prior studies, the infrastructure expenses and prospects for breakthrough advances are included. This first year's focus is on determining the key questions to enable the analysis. Accordingly, a work breakdown structure to organize the information and associated list of variables is offered. A flow diagram of the basic analysis is presented, as well as more detailed methods to convert the performance measures of disparate propulsion methods into common measures of energy, mass, time, and power. Other methods for equitable comparisons include evaluating the prospects under the same assumptions of payload, mission trajectory, and available energy. Missions are divided into three eras of readiness (precursors, era of infrastructure, and era of breakthroughs) as a first step before proceeding to include comparisons of technology advancement rates. Final evaluation "figures of merit" are offered. Preliminary lists of mission architectures and propulsion prospects are provided. -
100 Closest Stars Designation R.A
100 closest stars Designation R.A. Dec. Mag. Common Name 1 Gliese+Jahreis 551 14h30m –62°40’ 11.09 Proxima Centauri Gliese+Jahreis 559 14h40m –60°50’ 0.01, 1.34 Alpha Centauri A,B 2 Gliese+Jahreis 699 17h58m 4°42’ 9.53 Barnard’s Star 3 Gliese+Jahreis 406 10h56m 7°01’ 13.44 Wolf 359 4 Gliese+Jahreis 411 11h03m 35°58’ 7.47 Lalande 21185 5 Gliese+Jahreis 244 6h45m –16°49’ -1.43, 8.44 Sirius A,B 6 Gliese+Jahreis 65 1h39m –17°57’ 12.54, 12.99 BL Ceti, UV Ceti 7 Gliese+Jahreis 729 18h50m –23°50’ 10.43 Ross 154 8 Gliese+Jahreis 905 23h45m 44°11’ 12.29 Ross 248 9 Gliese+Jahreis 144 3h33m –9°28’ 3.73 Epsilon Eridani 10 Gliese+Jahreis 887 23h06m –35°51’ 7.34 Lacaille 9352 11 Gliese+Jahreis 447 11h48m 0°48’ 11.13 Ross 128 12 Gliese+Jahreis 866 22h39m –15°18’ 13.33, 13.27, 14.03 EZ Aquarii A,B,C 13 Gliese+Jahreis 280 7h39m 5°14’ 10.7 Procyon A,B 14 Gliese+Jahreis 820 21h07m 38°45’ 5.21, 6.03 61 Cygni A,B 15 Gliese+Jahreis 725 18h43m 59°38’ 8.90, 9.69 16 Gliese+Jahreis 15 0h18m 44°01’ 8.08, 11.06 GX Andromedae, GQ Andromedae 17 Gliese+Jahreis 845 22h03m –56°47’ 4.69 Epsilon Indi A,B,C 18 Gliese+Jahreis 1111 8h30m 26°47’ 14.78 DX Cancri 19 Gliese+Jahreis 71 1h44m –15°56’ 3.49 Tau Ceti 20 Gliese+Jahreis 1061 3h36m –44°31’ 13.09 21 Gliese+Jahreis 54.1 1h13m –17°00’ 12.02 YZ Ceti 22 Gliese+Jahreis 273 7h27m 5°14’ 9.86 Luyten’s Star 23 SO 0253+1652 2h53m 16°53’ 15.14 24 SCR 1845-6357 18h45m –63°58’ 17.40J 25 Gliese+Jahreis 191 5h12m –45°01’ 8.84 Kapteyn’s Star 26 Gliese+Jahreis 825 21h17m –38°52’ 6.67 AX Microscopii 27 Gliese+Jahreis 860 22h28m 57°42’ 9.79, -
Metallicities of the Β Cephei Stars from Low-Resolution Ultraviolet Spectra
A&A 433, 659–669 (2005) Astronomy DOI: 10.1051/0004-6361:20040396 & c ESO 2005 Astrophysics Metallicities of the β Cephei stars from low-resolution ultraviolet spectra E. Niemczura and J. Daszynska-Daszkiewicz´ Astronomical Institute, Wrocław University, ul. Kopernika 11, 51-622 Wrocław, Poland e-mail: [email protected] Received 5 March 2004 / Accepted 22 November 2004 Abstract. We derive basic stellar parameters (angular diameters, effective temperatures, metallicities) and interstellar reddening for all β Cephei stars observed during the IUE satellite mission, including those belonging to three open clusters. The parameters are derived by means of an algorithmic procedure of fitting theoretical flux distributions to the low-resolution IUE spectra and ground-based spectrophotometric observations. Since the metallicity has a special importance for pulsating B-type stars, we focus our attention in particular on this parameter. Key words. stars: early-type – stars: abundances – stars: variables: general 1. Introduction In this paper we analyze the IUE (International Ultraviolet Explorer) data combined with ground-based spectrophotomet- β Cephei variables are a well-known group of early B-type ric observations of β Cephei stars. The ultraviolet (UV) part pulsating stars. Their pulsations are driven by the classical of the spectra of main-sequence B-type stars is very rich in κ-mechanism, operating in the layer of the metal opacity bump lines of the iron-group elements. Because the greatest amount ≈ × 5 at T 2 10 K caused by the large number of absorption of energy for these objects is emitted in the spectral region be- lines of the iron-group elements. -
物理雙月刊29-3 621-772.Pdf
ᒳृݧ ʳ ౨ᄭઝݾറᙀ ᚮࣔᏕ/֮ ΔࢨუԵᛵᇞݺଚشଶಬߨጿጿլឰऱਞ ၦऱࠌ ౨ᄭऱ࣠Δኙ٤شॸΔ᠏ณհၴԾࠩԱքΕԮִ መ৫ࠌ ഏᎾၴऱڇऱᐙګԳพஒऱ ᛩቼࢬທח᥆࣍ङऱֲΔ עء۶ΔլោᥦԫՀڕټᚰۖࠐΖ ඈچᑷԫंंլឰ Δᑷ รԼᒧറ֮ΚψൕഏᎾᛩቼਐᑇࡌ௧ᛩ៥ऱ ऱ࿇ሽ౨ᄭऱᛘΔ ֗ IEA อૠװထԫैཀհլ݈ ωΔᇠᒧ֮ີტխᘋՕᖂ܉ऱՕհխΔᨃԳ ։ᗺ៥࣍ ᤚຑ़Εຑ௧ຟआᤴ ढߓ୪ւࣳඒ࣍ඒᖂઔߒ խࢼ़ݺଚᐷᐊΖڦۍऱ ᎩհᎾΔڼԱΖՈࠌଖ ᆖᛎࡉഏԺऱ࿇୶זᆏᆏՂ چሽլឰشڞऱ ᎅ࠷ެ࣍౨ᄭױሽ ፖᑓΔ༓شڇΔኚ໌ΖྥۖΔ֒ Δޡݾऱၞشࠡሎ֗شழΔݺଚՈՕ ऱࠌٵཚऱ ᎅਢԫഏᆖᛎ࿇୶ऱױCO2 ऱඈ࣋ၦࡉᄵயᚨ ౨ᄭ ٺΔ౨ᄭᤜᠲኙ࣍ڼڂऱ༞֏ΔထኔఎՀԱլ֟լߜ ೯ԺΖ ࡳࢤެڶᏆऱ࿇୶ࠠٺڇᄊ֏ ഏچຒףԱګऱધᙕΔՈ ߪᣂএࠩԫषᄎՕฒऱ壂ઘࡉֲൄढ֊ޓயᚨऱං֫հԫΖ ऱᐙΔ ฒاڇवኙ࣍ Ꮭऱं೯ΖᅝഏᎾईᏝՂཆΔഏփढᏝঁஓஓױݺଚࠆ࠹ԫաऱ堚ළፖঁ൸հᎾΔڇ ՂይΖچΔ ऱৼᜢխᆥྤݲᐫᇷᄭᤖ៲ຆΔ౨ᄭ༓٤ᑇٛᘸၞՑऱྥ֚ 9 ڣ ࣍ 2005ޓࠐΔईᏝᆏᆏ֒Δڣၦথբ २༓شࢬऱؓ݁ሽၦࡉ౨ᄭࠌڣޢԳޢݺଚ ද࣍ US$70 ऱ໌ޢࠐऱᖵᄅΔሒڣۍሽ ִٝડధڇ౨ᄭΕڇऱছૄΜૉ൞უڇټਢඈ ᄭ۞ᖏञࡉైڂຝ։ڶᄅધᙕΖईᏝऱं೯ឈ ᚮࣔᏕ ౨ᄭفՂ֏چլ؆ਢڂԫ܀ਙएࠃٙΔ 堚ဎՕᖂढߓمഏ ڶईΕ֚ྥࡉᅁ౨ᄭᗏற)ऱᤖ៲ၦึߒفऑਐ) E-mail: [email protected] ࢤΔૉشऱ౨ᄭࠌڶૻΖറ୮ေ۷ૉᖕԳᣊ Ϯ621Ϯʳ քִʳڣ ˊ˃˃˅ʻ֥࠴Կཚʼʳעढᠨִ ᒳृݧ ༚ྼऱႨΖᅝᓫᓵᇠ֘ுΛࢨਢᇠᖑுΛംᠲڶۖ ࠩބயऱᆏ౨ֱூΔࢨլᕣݶ༈ڶإటנ༼౨آᙈᙈ ᇞு౨ᗏறऱ፹ທመچհছΔषᄎՕฒᚨᇠ٣堚ᄑ ڶՂೈᅁᇷᄭࡸچ౨ᄭऱᇩΔঞזࠠயհཙ ؆ਜ਼ழऱۆுᘿ୴֗אΔ܂࿓ࡉு౨࿇ሽऱՠ فईࡉ֚ྥ֏فڕהऱᤖ៲ၦ؆Δࠡ׳ؐڣ 200 ࢤড়ᨠऱኪ৫אթ౨ڼڕୌࠄΔڶՂऱ ᥨൻਜࠩࢍאڣ ౨ྤऄ֭ᐶመ 50ױၦቃ۷ژᗏறऱᚏ ཚءΔڼڂᖗΖހᒔऱإԫנு౨࿇ሽشࠌܡၦΖ ਢޣ౨ᄭ᜔Ꮑ ሽֆுԿᐗૠቤิ९ದ໑Փऱᑷ֧֨ᗏ ܑຘመف᠏ངயለհႚอ֏܅ءګΔᆖᛎۖྥ ሽֆு౨࿇ሽኔ೭ᆖ᧭ऱڣڍڶࠩԱٍࠠބऱሽ౨ Δشऴ൷ࠌאԫՕฒګ᠏ངڇΔشறऱࠌ ،ݺଚ֮റ૪ψࢢسࢨᑷ౨ऱመ࿓խΔᄎ ு֨ᛜሎᓰᓰ९׆ᐚᆠ٣(شԺ࿇ሽ)Ε೯౨(ሎᙁ־อጠ) ॺൄ᧩࣐ᚩऱאԱᇞ،--ு౨࿇ሽᓫωΔᇠ֮ڕլ ۆᎨॸΔᖄીᣤૹऱᛩቼګඈ࣋Օၦऱᄵ᧯ࡉݮ ຝٺᎅࣔԱு౨࿇ሽऱچᦰृ堚ᄑڗऱؓ݁ᄵ৫ 壄֮چࡉֲᣤૹऱᄵயᚨΔၞۖᖄી ኪؓᘝ ੌ࿓ࡉுᗏறՄऱ፹ທመ࿓Δਢԫᒧॺൄଖԫᦰऱسऱڶऱ۞ྥᛩቼࡉچኙۖڂດዬՂ֒Ζ ኪᛩቼ૿ ֮ີΖسऱچऱᣤૹᓢᚰΔࠌڃனױլګؘലທ ٤ᤜᠲǵഏᎾईᏝࡺլڜईفᜯ؎ՕऱਗᖏΖ ࠹ࠩ٤ ՂഏᎾၴᒤᄵ᧯ඈ࣋྇ၦࢭᘭհᛩঅֆףࡉଢऱ᧢ᔢࢬທ ՀΔ᧢ޏኙᛩቼऱشᣂ౨ᄭሎڶ ڂᛩঅრᢝይ֗אඔ೯ΔڤإऱᐙຍଡૹᤜᠲΔݺଚܑࡡᓮՠᄐݾઔߒ પψࠇຟᤜࡳωګ ԳᣊؘߨհሁΖ۶ᘯګ౨ᄭسᡖᐚ ైऱᓢᚰՀΔං೯٦ۂ(Հ១ጠՠઔೃ౨ᛩࢬא)ೃ౨ᄭፖᛩቼઔߒࢬ ౨ᄭ࿇ሽωٍᆖسรքᒧറ֮ψ٦עء౨ᄭΛس٦ -
The Transfiguration in the Theology of Gregory Palamas And
Duquesne University Duquesne Scholarship Collection Electronic Theses and Dissertations Spring 2015 Deus in se et Deus pro nobis: The rT ansfiguration in the Theology of Gregory Palamas and Its Importance for Catholic Theology Cory Hayes Follow this and additional works at: https://dsc.duq.edu/etd Recommended Citation Hayes, C. (2015). Deus in se et Deus pro nobis: The rT ansfiguration in the Theology of Gregory Palamas and Its Importance for Catholic Theology (Doctoral dissertation, Duquesne University). Retrieved from https://dsc.duq.edu/etd/640 This Immediate Access is brought to you for free and open access by Duquesne Scholarship Collection. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Duquesne Scholarship Collection. For more information, please contact [email protected]. DEUS IN SE ET DEUS PRO NOBIS: THE TRANSFIGURATION IN THE THEOLOGY OF GREGORY PALAMAS AND ITS IMPORTANCE FOR CATHOLIC THEOLOGY A Dissertation Submitted to the McAnulty Graduate School of Liberal Arts Duquesne University In partial fulfillment of the requirements for the degree of Doctor of Philosophy By Cory J. Hayes May 2015 Copyright by Cory J. Hayes 2015 DEUS IN SE ET DEUS PRO NOBIS: THE TRANSFIGURATION IN THE THEOLOGY OF GREGORY PALAMAS AND ITS IMPORTANCE FOR CATHOLIC THEOLOGY By Cory J. Hayes Approved March 31, 2015 _______________________________ ______________________________ Dr. Bogdan Bucur Dr. Radu Bordeianu Associate Professor of Theology Associate Professor of Theology (Committee Chair) (Committee Member) _______________________________ Dr. Christiaan Kappes Professor of Liturgy and Patristics Saints Cyril and Methodius Byzantine Catholic Seminary (Committee Member) ________________________________ ______________________________ Dr. James Swindal Dr. -
Useful Constants
Appendix A Useful Constants A.1 Physical Constants Table A.1 Physical constants in SI units Symbol Constant Value c Speed of light 2.997925 × 108 m/s −19 e Elementary charge 1.602191 × 10 C −12 2 2 3 ε0 Permittivity 8.854 × 10 C s / kgm −7 2 μ0 Permeability 4π × 10 kgm/C −27 mH Atomic mass unit 1.660531 × 10 kg −31 me Electron mass 9.109558 × 10 kg −27 mp Proton mass 1.672614 × 10 kg −27 mn Neutron mass 1.674920 × 10 kg h Planck constant 6.626196 × 10−34 Js h¯ Planck constant 1.054591 × 10−34 Js R Gas constant 8.314510 × 103 J/(kgK) −23 k Boltzmann constant 1.380622 × 10 J/K −8 2 4 σ Stefan–Boltzmann constant 5.66961 × 10 W/ m K G Gravitational constant 6.6732 × 10−11 m3/ kgs2 M. Benacquista, An Introduction to the Evolution of Single and Binary Stars, 223 Undergraduate Lecture Notes in Physics, DOI 10.1007/978-1-4419-9991-7, © Springer Science+Business Media New York 2013 224 A Useful Constants Table A.2 Useful combinations and alternate units Symbol Constant Value 2 mHc Atomic mass unit 931.50MeV 2 mec Electron rest mass energy 511.00keV 2 mpc Proton rest mass energy 938.28MeV 2 mnc Neutron rest mass energy 939.57MeV h Planck constant 4.136 × 10−15 eVs h¯ Planck constant 6.582 × 10−16 eVs k Boltzmann constant 8.617 × 10−5 eV/K hc 1,240eVnm hc¯ 197.3eVnm 2 e /(4πε0) 1.440eVnm A.2 Astronomical Constants Table A.3 Astronomical units Symbol Constant Value AU Astronomical unit 1.4959787066 × 1011 m ly Light year 9.460730472 × 1015 m pc Parsec 2.0624806 × 105 AU 3.2615638ly 3.0856776 × 1016 m d Sidereal day 23h 56m 04.0905309s 8.61640905309 -
Open Batalha-Dissertation.Pdf
The Pennsylvania State University The Graduate School Eberly College of Science A SYNERGISTIC APPROACH TO INTERPRETING PLANETARY ATMOSPHERES A Dissertation in Astronomy and Astrophysics by Natasha E. Batalha © 2017 Natasha E. Batalha Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2017 The dissertation of Natasha E. Batalha was reviewed and approved∗ by the following: Steinn Sigurdsson Professor of Astronomy and Astrophysics Dissertation Co-Advisor, Co-Chair of Committee James Kasting Professor of Geosciences Dissertation Co-Advisor, Co-Chair of Committee Jason Wright Professor of Astronomy and Astrophysics Eric Ford Professor of Astronomy and Astrophysics Chris Forest Professor of Meteorology Avi Mandell NASA Goddard Space Flight Center, Research Scientist Special Signatory Michael Eracleous Professor of Astronomy and Astrophysics Graduate Program Chair ∗Signatures are on file in the Graduate School. ii Abstract We will soon have the technological capability to measure the atmospheric compo- sition of temperate Earth-sized planets orbiting nearby stars. Interpreting these atmospheric signals poses a new challenge to planetary science. In contrast to jovian-like atmospheres, whose bulk compositions consist of hydrogen and helium, terrestrial planet atmospheres are likely comprised of high mean molecular weight secondary atmospheres, which have gone through a high degree of evolution. For example, present-day Mars has a frozen surface with a thin tenuous atmosphere, but 4 billion years ago it may have been warmed by a thick greenhouse atmosphere. Several processes contribute to a planet’s atmospheric evolution: stellar evolution, geological processes, atmospheric escape, biology, etc. Each of these individual processes affects the planetary system as a whole and therefore they all must be considered in the modeling of terrestrial planets. -
The Impact of Giant Stellar Outflows on Molecular Clouds
The Impact of Giant Stellar Outflows on Molecular Clouds A thesis presented by H´ector G. Arce Nazario to The Department of Astronomy in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Astronomy Harvard University Cambridge, Massachusetts October, 2001 c 2001, by H´ector G. Arce Nazario All Rights Reserved ABSTRACT Thesis Advisor: Alyssa A. Goodman Thesis by: H´ector G. Arce Nazario We use new millimeter wavelength observations to reveal the important effects that giant (parsec-scale) outflows from young stars have on their surroundings. We find that giant outflows have the potential to disrupt their host cloud, and/or drive turbulence there. In addition, our study confirms that episodicity and a time-varying ejection axis are common characteristics of giant outflows. We carried out our study by mapping, in great detail, the surrounding molecular gas and parent cloud of two giant Herbig-Haro (HH) flows; HH 300 and HH 315. Our study shows that these giant HH flows have been able to entrain large amounts of molecular gas, as the molecular outflows they have produced have masses of 4 to 7 M |which is approximately 5 to 10% of the total quiescent gas mass in their parent clouds. These outflows have injected substantial amounts of −1 momentum and kinetic energy on their parent cloud, in the order of 10 M km s and 1044 erg, respectively. We find that both molecular outflows have energies comparable to their parent clouds' turbulent and gravitationally binding energies. In addition, these outflows have been able to redistribute large amounts of their surrounding medium-density (n ∼ 103 cm−3) gas, thereby sculpting their parent cloud and affecting its density and velocity distribution at distances as large as 1 to 1.5 pc from the outflow source. -
Physical Processes in the Interstellar Medium
Physical Processes in the Interstellar Medium Ralf S. Klessen and Simon C. O. Glover Abstract Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understand- ing its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolu- tion, the formation of stars, cosmic nucleosynthesis, the origin of large com- plex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the interstellar medium. However, despite its importance, its structure and evolution is still not fully understood. Observations reveal that the interstellar medium is highly tur- bulent, consists of different chemical phases, and is characterized by complex structure on all resolvable spatial and temporal scales. Our current numerical and theoretical models describe it as a strongly coupled system that is far from equilibrium and where the different components are intricately linked to- gether by complex feedback loops. Describing the interstellar medium is truly a multi-scale and multi-physics problem. In these lecture notes we introduce the microphysics necessary to better understand the interstellar medium. We review the relations between large-scale and small-scale dynamics, we con- sider turbulence as one of the key drivers of galactic evolution, and we review the physical processes that lead to the formation of dense molecular clouds and that govern stellar birth in their interior. Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, 69120 Heidelberg, Germany e-mail: [email protected], [email protected] 1 Contents Physical Processes in the Interstellar Medium ............... -
AD Leonis: Flares Observed by XMM-Newton and Chandra
A&A 411, 587–593 (2003) Astronomy DOI: 10.1051/0004-6361:20031398 & c ESO 2003 Astrophysics AD Leonis: Flares observed by XMM-Newton and Chandra E. J. M. van den Besselaar1;2, A. J. J. Raassen1;3,R.Mewe1,R.L.J.vanderMeer1,M.G¨udel4, and M. Audard5 1 SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: [email protected];[email protected];[email protected] 2 Department of Astrophysics, University of Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands 3 Astronomical Institute “Anton Pannekoek”, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands 4 Paul Scherrer Institut, W¨urenlingen & Villigen, 5232 Villigen PSI, Switzerland e-mail: [email protected] 5 Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027, USA e-mail: [email protected] Received 3 February 2003 / Accepted 2 September 2003 Abstract. The M-dwarf AD Leonis has been observed with the Reflection Grating Spectrometers and the European Photon Imaging Camera aboard XMM-Newton and also with the Low Energy Transmission Grating Spectrometer aboard the Chandra X-ray Observatory. In the observation taken with XMM-Newton five large flares produced by AD Leo were identified and only one in the observation taken with Chandra. A quiescent level to the lightcurves is difficult to define, since several smaller flares mutually overlap each other. However, we defined a quasi-steady state outside of obvious flares or flare decays. The spectra from the flare state and the quasi-steady state are analysed separately.