Spectral Classification of Stars
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Spectroscopic Analysis of Accretion/Ejection Signatures in the Herbig Ae/Be Stars HD 261941 and V590 Mon T Moura, S
Spectroscopic analysis of accretion/ejection signatures in the Herbig Ae/Be stars HD 261941 and V590 Mon T Moura, S. Alencar, A. Sousa, E. Alecian, Y. Lebreton To cite this version: T Moura, S. Alencar, A. Sousa, E. Alecian, Y. Lebreton. Spectroscopic analysis of accretion/ejection signatures in the Herbig Ae/Be stars HD 261941 and V590 Mon. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2020, 494 (3), pp.3512-3535. 10.1093/mnras/staa695. hal-02523038 HAL Id: hal-02523038 https://hal.archives-ouvertes.fr/hal-02523038 Submitted on 16 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. MNRAS 000,1–24 (2019) Preprint 27 February 2020 Compiled using MNRAS LATEX style file v3.0 Spectroscopic analysis of accretion/ejection signatures in the Herbig Ae/Be stars HD 261941 and V590 Mon T. Moura1?, S. H. P. Alencar1, A. P. Sousa1;2, E. Alecian2, Y. Lebreton3;4 1Universidade Federal de Minas Gerais, Departamento de Física, Av. Antônio Carlos 6627, 31270-901, Brazil 2Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France 3LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. -
Plotting Variable Stars on the H-R Diagram Activity
Pulsating Variable Stars and the Hertzsprung-Russell Diagram The Hertzsprung-Russell (H-R) Diagram: The H-R diagram is an important astronomical tool for understanding how stars evolve over time. Stellar evolution can not be studied by observing individual stars as most changes occur over millions and billions of years. Astrophysicists observe numerous stars at various stages in their evolutionary history to determine their changing properties and probable evolutionary tracks across the H-R diagram. The H-R diagram is a scatter graph of stars. When the absolute magnitude (MV) – intrinsic brightness – of stars is plotted against their surface temperature (stellar classification) the stars are not randomly distributed on the graph but are mostly restricted to a few well-defined regions. The stars within the same regions share a common set of characteristics. As the physical characteristics of a star change over its evolutionary history, its position on the H-R diagram The H-R Diagram changes also – so the H-R diagram can also be thought of as a graphical plot of stellar evolution. From the location of a star on the diagram, its luminosity, spectral type, color, temperature, mass, age, chemical composition and evolutionary history are known. Most stars are classified by surface temperature (spectral type) from hottest to coolest as follows: O B A F G K M. These categories are further subdivided into subclasses from hottest (0) to coolest (9). The hottest B stars are B0 and the coolest are B9, followed by spectral type A0. Each major spectral classification is characterized by its own unique spectra. -
RADIAL VELOCITIES in the ZODIACAL DUST CLOUD
A SURVEY OF RADIAL VELOCITIES in the ZODIACAL DUST CLOUD Brian Harold May Astrophysics Group Department of Physics Imperial College London Thesis submitted for the Degree of Doctor of Philosophy to Imperial College of Science, Technology and Medicine London · 2007 · 2 Abstract This thesis documents the building of a pressure-scanned Fabry-Perot Spectrometer, equipped with a photomultiplier and pulse-counting electronics, and its deployment at the Observatorio del Teide at Izaña in Tenerife, at an altitude of 7,700 feet (2567 m), for the purpose of recording high-resolution spectra of the Zodiacal Light. The aim was to achieve the first systematic mapping of the MgI absorption line in the Night Sky, as a function of position in heliocentric coordinates, covering especially the plane of the ecliptic, for a wide variety of elongations from the Sun. More than 250 scans of both morning and evening Zodiacal Light were obtained, in two observing periods – September-October 1971, and April 1972. The scans, as expected, showed profiles modified by components variously Doppler-shifted with respect to the unshifted shape seen in daylight. Unexpectedly, MgI emission was also discovered. These observations covered for the first time a span of elongations from 25º East, through 180º (the Gegenschein), to 27º West, and recorded average shifts of up to six tenths of an angstrom, corresponding to a maximum radial velocity relative to the Earth of about 40 km/s. The set of spectra obtained is in this thesis compared with predictions made from a number of different models of a dust cloud, assuming various distributions of dust density as a function of position and particle size, and differing assumptions about their speed and direction. -
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, -
• Classifying Stars: HR Diagram • Luminosity, Radius, and Temperature • “Vogt-Russell” Theorem • Main Sequence • Evolution on the HR Diagram
Stars • Classifying stars: HR diagram • Luminosity, radius, and temperature • “Vogt-Russell” theorem • Main sequence • Evolution on the HR diagram Classifying stars • We now have two properties of stars that we can measure: – Luminosity – Color/surface temperature • Using these two characteristics has proved extraordinarily effective in understanding the properties of stars – the Hertzsprung- Russell (HR) diagram If we plot lots of stars on the HR diagram, they fall into groups These groups indicate types of stars, or stages in the evolution of stars Luminosity classes • Class Ia,b : Supergiant • Class II: Bright giant • Class III: Giant • Class IV: Sub-giant • Class V: Dwarf The Sun is a G2 V star Luminosity versus radius and temperature A B R = R R = 2 RSun Sun T = T T = TSun Sun Which star is more luminous? Luminosity versus radius and temperature A B R = R R = 2 RSun Sun T = T T = TSun Sun • Each cm2 of each surface emits the same amount of radiation. • The larger stars emits more radiation because it has a larger surface. It emits 4 times as much radiation. Luminosity versus radius and temperature A1 B R = RSun R = RSun T = TSun T = 2TSun Which star is more luminous? The hotter star is more luminous. Luminosity varies as T4 (Stefan-Boltzmann Law) Luminosity Law 2 4 LA = RATA 2 4 LB RBTB 1 2 If star A is 2 times as hot as star B, and the same radius, then it will be 24 = 16 times as luminous. From a star's luminosity and temperature, we can calculate the radius. -
Chapter 16 the Sun and Stars
Chapter 16 The Sun and Stars Stargazing is an awe-inspiring way to enjoy the night sky, but humans can learn only so much about stars from our position on Earth. The Hubble Space Telescope is a school-bus-size telescope that orbits Earth every 97 minutes at an altitude of 353 miles and a speed of about 17,500 miles per hour. The Hubble Space Telescope (HST) transmits images and data from space to computers on Earth. In fact, HST sends enough data back to Earth each week to fill 3,600 feet of books on a shelf. Scientists store the data on special disks. In January 2006, HST captured images of the Orion Nebula, a huge area where stars are being formed. HST’s detailed images revealed over 3,000 stars that were never seen before. Information from the Hubble will help scientists understand more about how stars form. In this chapter, you will learn all about the star of our solar system, the sun, and about the characteristics of other stars. 1. Why do stars shine? 2. What kinds of stars are there? 3. How are stars formed, and do any other stars have planets? 16.1 The Sun and the Stars What are stars? Where did they come from? How long do they last? During most of the star - an enormous hot ball of gas day, we see only one star, the sun, which is 150 million kilometers away. On a clear held together by gravity which night, about 6,000 stars can be seen without a telescope. -
Star Systems in the Solar Neighborhood up to 10 Parsecs Distance
Vol. 16 No. 3 June 15, 2020 Journal of Double Star Observations Page 229 Star Systems in the Solar Neighborhood up to 10 Parsecs Distance Wilfried R.A. Knapp Vienna, Austria [email protected] Abstract: The stars and star systems in the solar neighborhood are for obvious reasons the most likely best investigated stellar objects besides the Sun. Very fast proper motion catches the attention of astronomers and the small distances to the Sun allow for precise measurements so the wealth of data for most of these objects is impressive. This report lists 94 star systems (doubles or multiples most likely bound by gravitation) in up to 10 parsecs distance from the Sun as well over 60 questionable objects which are for different reasons considered rather not star systems (at least not within 10 parsecs) but might be if with a small likelihood. A few of the listed star systems are newly detected and for several systems first or updated preliminary orbits are suggested. A good part of the listed nearby star systems are included in the GAIA DR2 catalog with par- allax and proper motion data for at least some of the components – this offers the opportunity to counter-check the so far reported data with the most precise star catalog data currently available. A side result of this counter-check is the confirmation of the expectation that the GAIA DR2 single star model is not well suited to deliver fully reliable parallax and proper motion data for binary or multiple star systems. 1. Introduction high proper motion speed might cause visually noticea- The answer to the question at which distance the ble position changes from year to year. -
Surfing on a Flash of Light from an Exploding Star ______By Abraham Loeb on December 26, 2019
Surfing on a Flash of Light from an Exploding Star _______ By Abraham Loeb on December 26, 2019 A common sight on the beaches of Hawaii is a crowd of surfers taking advantage of a powerful ocean wave to reach a high speed. Could extraterrestrial civilizations have similar aspirations for sailing on a powerful flash of light from an exploding star? A light sail weighing less than half a gram per square meter can reach the speed of light even if it is separated from the exploding star by a hundred times the distance of the Earth from the Sun. This results from the typical luminosity of a supernova, which is equivalent to a billion suns shining for a month. The Sun itself is barely capable of accelerating an optimally designed sail to just a thousandth of the speed of light, even if the sail starts its journey as close as ten times the Solar radius – the closest approach of the Parker Solar Probe. The terminal speed scales as the square root of the ratio between the star’s luminosity over the initial distance, and can reach a tenth of the speed of light for the most luminous stars. Powerful lasers can also push light sails much better than the Sun. The Breakthrough Starshot project aims to reach several tenths of the speed of light by pushing a lightweight sail for a few minutes with a laser beam that is ten million times brighter than sunlight on Earth (with ten gigawatt per square meter). Achieving this goal requires a major investment in building the infrastructure needed to produce and collimate the light beam. -
La Photosynthèse Serait Apparue Chez Certains Organismes Primitifs Entre 2.800 Et -2.400 Millions D’Années Si L’On En Croit Certaines Archives Géologiques Terrestres
La photosynthèse serait apparue chez certains organismes primitifs entre 2.800 et -2.400 millions d’années si l’on en croit certaines archives géologiques terrestres. Mais certains la font remonter bien plus tôt en faisant l’hypothèse que les stromatolites que l’on retrouve dans des couches plus anciennes encore sont bien le produit d’une activité biologique. Actuellement, nous n’en sommes sûrs que pour ceux datant de -2.724 millions d’années mais des stromatolites existaient déjà sur Terre il y a 3,5 milliards d’années environ. Quoiqu'il en soit, une certitude demeure, concernant les immenses dépôts de fer du bassin de Hamersley en Australie. Ils datent de l’époque du Sidérien alors que la surface des continents était devenue suffisamment importante pour que se forment des mers peu profondes entourées de grande plates-formes continentales. Les conditions étaient remplies pour que de grands tapis de bactéries construisent des stromatolites en quantités importantes et dégagent massivement de l’oxygène par photosynthèse. Ce gaz corrosif a alors pu oxyder le fer en solution dans les océans et entraîner sa précipitation sous forme d’hydroxyde de fer, de carbonate de fer, de silicate ou de sulfures, selon des variations de l’acidité et du degré d’oxydoréduction de l’eau de mer. C’est ce qu’on appelle la Grande oxydation ou la Catastrophe de l’oxygène. Vers -1.900 millions d’années, la presque totalité du fer présent dans les océans avait précipité et il se retrouve aujourd’hui dans les grands gisements de minerai mondiaux tels que ceux de Hamersley. -
Sludgefinder 2 Sixth Edition Rev 1
SludgeFinder 2 Instruction Manual 2 PULSAR MEASUREMENT SludgeFinder 2 (SIXTH EDITION REV 1) February 2021 Part Number M-920-0-006-1P COPYRIGHT © Pulsar Measurement, 2009 -21. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form without the written permission of Pulsar Process Measurement Limited. WARRANTY AND LIABILITY Pulsar Measurement guarantee for a period of 2 years from the date of delivery that it will either exchange or repair any part of this product returned to Pulsar Process Measurement Limited if it is found to be defective in material or workmanship, subject to the defect not being due to unfair wear and tear, misuse, modification or alteration, accident, misapplication, or negligence. Note: For a VT10 or ST10 transducer the period of time is 1 year from date of delivery. DISCLAIMER Pulsar Measurement neither gives nor implies any process guarantee for this product and shall have no liability in respect of any loss, injury or damage whatsoever arising out of the application or use of any product or circuit described herein. Every effort has been made to ensure accuracy of this documentation, but Pulsar Measurement cannot be held liable for any errors. Pulsar Measurement operates a policy of constant development and improvement and reserves the right to amend technical details, as necessary. The SludgeFinder 2 shown on the cover of this manual is used for illustrative purposes only and may not be representative -
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 -
1 Director's Message
1 Director’s Message Markus Kissler-Patig 3 Weighing the Black Hole in M101 ULX-1 Stephen Justham and Jifeng Liu 8 World’s Most Powerful Planet Finder Turns its Eye to the Sky: First Light with the Gemini Planet Imager Bruce Macintosh and Peter Michaud 12 Science Highlights Nancy A. Levenson 15 Operations Corner: Update and 2013 Review Andy Adamson 20 Instrumentation Development: Update and 2013 Review Scot Kleinman ON THE COVER: GeminiFocus January 2014 The cover of this issue GeminiFocus is a quarterly publication of Gemini Observatory features first light images from the Gemini 670 N. A‘ohoku Place, Hilo, Hawai‘i 96720 USA Planet Imager that Phone: (808) 974-2500 Fax: (808) 974-2589 were released at the Online viewing address: January 2014 meeting www.gemini.edu/geminifocus of the American Managing Editor: Peter Michaud Astronomical Society Science Editor: Nancy A. Levenson held in Washington, D.C. Associate Editor: Stephen James O’Meara See the press release Designer: Eve Furchgott / Blue Heron Multimedia that accompanied the images starting on Any opinions, findings, and conclusions or recommendations page 8 of this issue. expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Markus Kissler-Patig Director’s Message 2013: A Successful Year for Gemini! As 2013 comes to an end, we can look back at 12 very successful months for Gemini despite strong budget constraints. Indeed, 2013 was the first stage of our three-year transition to a reduced opera- tions budget, and it was marked by a roughly 20 percent cut in contributions from Gemini’s partner countries.