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Interstellar Extinction in Orion. Variation of the Strength of the UV
MNRAS 000, 1–9 (2017) Preprint 9 July 2018 Compiled using MNRAS LATEX style file v3.0 Interstellar extinction in Orion. Variation of the strength of the UV bump across the complex. Leire Beitia-Antero,1⋆ Ana I. G´omez de Castro,1† 1AEGORA Research Group, Universidad Complutense de Madrid, Facultad de CC. Matem´aticas, Plaza de Ciencias 3, E-28040 Madrid Accepted XXX. Received YYY; in original form ZZZ ABSTRACT There is growing observational evidence of dust coagulation in the dense filaments within molecular clouds. Infrared observations show that the dust grains size distri- bution gets shallower and the relative fraction of small to large dust grains decreases as the local density increases. Ultraviolet (UV) observations show that the strength of the 2175 A˚ feature, the so-called UV bump, also decreases with cloud density. In this work, we apply the technique developed for the Taurus study to the Orion molecular cloud and confirm that the UV bump decreases over the densest cores of the cloud as well as in the heavily UV irradiated λ Orionis shell. The study has been extended to the Rosette cloud with uncertain results given the distance (1.3 kpc). Key words: ISM: dust, extinction 1 INTRODUCTION feature of the extinction curve, the so-called UV bump. The UV bump is, by far, the strongest spectral feature in the ex- The Interstellar Medium (ISM) is a complex ensemble of tinction curve but its source remains uncertain (see e.g. the gas, large molecules and dust coupled through the action of review by Draine (2003)). -
Cassiopeia a January2008
CASSIOPEIA A JANUARY2008 Cassiopeia A is the youngest (about 300 years old) known supernova Su Mo Tu We Th Fr Sa remnant in the Milky Way. Astronomers have used Chandra’s long ob - 01 02 03 04 05 servations of this remnant to make a map of the acceleration of elec - trons in this supernova remnant. The analysis shows that the electrons 06 07 08 09 10 11 12 are being accelerated to almost the maximum theoretical limit in some 13 14 15 16 17 18 19 parts of Cassiopeia A (Cas A) in what can be thought of as a “relativistic pinball machine.” Protons and ions, which make up the bulk of cosmic 20 21 22 23 24 25 26 rays, are expected to be accelerated in a similar way to the electrons. The Cas A observations thus provide strong evidence that supernova 27 28 29 30 31 remnants are key sites for energizing cosmic rays. 3C442A FEBRUARY2008 X -ray data from NASA’s Chandra X -ray Observatory and radio obser - Su Mo Tu We Th Fr Sa vations from the NSF’s Very Large Array show that a role reversal is 01 02 taking place in the middle of 3C442A - a system with two merging gal - 03 04 05 06 07 08 09 axies in the center. Chandra detects hot gas (blue) that has been push - ing aside the radio -bright gas (orange). This is the opposite of what 10 11 12 13 14 15 16 is typically found in these systems when jets from the supermassive black hole in the center create cavities in the hot gas surrounding the 17 18 19 20 21 22 23 galaxy. -
Young Super-Neptune Offers Clues to the Origin of Close-In Exoplanet 21 June 2016, by Rebecca Johnson
Young super-Neptune offers clues to the origin of close-in exoplanet 21 June 2016, by Rebecca Johnson planets in the same planetary system, or with more distant stars. These scenarios can be tested observationally by searching for young planets and studying their orbits. If the close-in population formed in place or migrated in through interactions with the natal disk, they reach their final orbital distances early on and will be found close in at young ages. In comparison, migrating a planet inward through interactions with other planets or more distant stars is effective on much longer timescales. If the latter processes dominate, planets will not be found close to their K2-33 b, shown in this illustration, is one of the youngest stars when they are young. exoplanets detected to date. It makes a complete orbit around its star in about five days. These two characteristics combined provide exciting new directions for planet-formation theories. K2-33b could have formed on a farther out orbit and quickly migrated inward. Alternatively, it could have formed in situ, or in place. Credit: NASA/JPL-Caltech A team of astronomers has confirmed the existence of a young planet, only 11 million years old, that orbits very close to its star (at 0.05 AU), with an orbital period of 5.4 days. Approximately 5 times the size of the Earth, the new planet is a "super-Neptune" and the youngest such planet This image shows the K2-33 system, and its planet known. The discovery lends unique insights into K2-33b, compared to our own solar system. -
323 — 15 Nov 2019 Editor: Bo Reipurth ([email protected]) List of Contents
THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 323 — 15 Nov 2019 Editor: Bo Reipurth ([email protected]) List of Contents The Star Formation Newsletter Interview ...................................... 3 Abstracts of Newly Accepted Papers ........... 5 Editor: Bo Reipurth [email protected] Abstracts of Newly Accepted Major Reviews . 35 Associate Editor: Anna McLeod Dissertation Abstracts ........................ 36 [email protected] New Jobs ..................................... 39 Technical Editor: Hsi-Wei Yen Meetings ..................................... 40 [email protected] Summary of Upcoming Meetings ............. 42 Editorial Board New Books ................................... 44 Joao Alves Alan Boss Jerome Bouvier Lee Hartmann Cover Picture Thomas Henning Paul Ho The ρ Ophiuchi clouds are among the nearest star Jes Jorgensen forming regions. While it has been observed in Charles J. Lada great detail at almost all wavelengths, only wide- Thijs Kouwenhoven field astrophotography can capture its magnificent Michael R. Meyer appearance. Ralph Pudritz Luis Felipe Rodr´ıguez Image courtesy Adam Block Ewine van Dishoeck http://www.adamblockphotos.com Hans Zinnecker http://caelumobservatory.com The Star Formation Newsletter is a vehicle for fast distribution of information of interest for as- tronomers working on star and planet formation and molecular clouds. You can submit material for the following sections: Abstracts of recently Submitting your abstracts accepted papers (only for papers sent to refereed journals), Abstracts of recently accepted major re- Latex macros for submitting abstracts views (not standard conference contributions), Dis- and dissertation abstracts (by e-mail to sertation Abstracts (presenting abstracts of new [email protected]) are appended to Ph.D dissertations), Meetings (announcing meet- each Call for Abstracts. -
Educator's Guide: Orion
Legends of the Night Sky Orion Educator’s Guide Grades K - 8 Written By: Dr. Phil Wymer, Ph.D. & Art Klinger Legends of the Night Sky: Orion Educator’s Guide Table of Contents Introduction………………………………………………………………....3 Constellations; General Overview……………………………………..4 Orion…………………………………………………………………………..22 Scorpius……………………………………………………………………….36 Canis Major…………………………………………………………………..45 Canis Minor…………………………………………………………………..52 Lesson Plans………………………………………………………………….56 Coloring Book…………………………………………………………………….….57 Hand Angles……………………………………………………………………….…64 Constellation Research..…………………………………………………….……71 When and Where to View Orion…………………………………….……..…77 Angles For Locating Orion..…………………………………………...……….78 Overhead Projector Punch Out of Orion……………………………………82 Where on Earth is: Thrace, Lemnos, and Crete?.............................83 Appendix………………………………………………………………………86 Copyright©2003, Audio Visual Imagineering, Inc. 2 Legends of the Night Sky: Orion Educator’s Guide Introduction It is our belief that “Legends of the Night sky: Orion” is the best multi-grade (K – 8), multi-disciplinary education package on the market today. It consists of a humorous 24-minute show and educator’s package. The Orion Educator’s Guide is designed for Planetarians, Teachers, and parents. The information is researched, organized, and laid out so that the educator need not spend hours coming up with lesson plans or labs. This has already been accomplished by certified educators. The guide is written to alleviate the fear of space and the night sky (that many elementary and middle school teachers have) when it comes to that section of the science lesson plan. It is an excellent tool that allows the parents to be a part of the learning experience. The guide is devised in such a way that there are plenty of visuals to assist the educator and student in finding the Winter constellations. -
Theoretical Limits of Star Sensor Accuracy †
sensors Article Theoretical Limits of Star Sensor Accuracy † Marcio A. A. Fialho 1,* and Daniele Mortari 2 1 Divisão de Eletrônica Aeroespacial (DIDEA), National Institute for Space Research (INPE), Av. dos Astronautas, 1758, São José dos Campos, SP 12227, Brazil 2 Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA; [email protected] * Correspondence: marcio.fi[email protected]; Tel.: +55-12-3208-6145 † This paper is a revised and extended version of a work previously published as a doctoral thesis chapter. Received: 17 October 2019; Accepted: 25 November 2019; Published: 5 December 2019 Abstract: To achieve mass, power and cost reduction, there is a trend to reduce the volume of many instruments aboard spacecraft, especially for small spacecraft (cubesats or nanosats) with very limited mass, volume and power budgets. With the current trend of miniaturizing spacecraft instruments one could naturally ask if is there a physical limit to this process for star sensors. This paper shows that there is a fundamental limit on star sensor accuracy, which depends on stellar distribution, star sensor dimensions and exposure time. An estimate of this limit is given for our location in the galaxy. Keywords: star sensors; stellar distribution; photometry; astrometry; star catalogs; fundamental limits 1. Introduction Much progress in a variety of fields in science and technology could be accomplished thanks to the miniaturization obtained in microelectronics in the recent decades. One of the most remarkable examples is the prediction by Gordon Moore that the computational power would increase exponentially, an empirical observation that became known as Moore’s law [1–4]. -
Fy10 Budget by Program
AURA/NOAO FISCAL YEAR ANNUAL REPORT FY 2010 Revised Submitted to the National Science Foundation March 16, 2011 This image, aimed toward the southern celestial pole atop the CTIO Blanco 4-m telescope, shows the Large and Small Magellanic Clouds, the Milky Way (Carinae Region) and the Coal Sack (dark area, close to the Southern Crux). The 33 “written” on the Schmidt Telescope dome using a green laser pointer during the two-minute exposure commemorates the rescue effort of 33 miners trapped for 69 days almost 700 m underground in the San Jose mine in northern Chile. The image was taken while the rescue was in progress on 13 October 2010, at 3:30 am Chilean Daylight Saving time. Image Credit: Arturo Gomez/CTIO/NOAO/AURA/NSF National Optical Astronomy Observatory Fiscal Year Annual Report for FY 2010 Revised (October 1, 2009 – September 30, 2010) Submitted to the National Science Foundation Pursuant to Cooperative Support Agreement No. AST-0950945 March 16, 2011 Table of Contents MISSION SYNOPSIS ............................................................................................................ IV 1 EXECUTIVE SUMMARY ................................................................................................ 1 2 NOAO ACCOMPLISHMENTS ....................................................................................... 2 2.1 Achievements ..................................................................................................... 2 2.2 Status of Vision and Goals ................................................................................ -
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. -
At the Harvard Observatory
Book Reviews 117 gravitational wave physicists, all of whom are members of an international group of over a thousand scientists engaged with the detection apparatus at two widely separated sites, one in Livingston, Louisiana and the other in Hanford, Washington. The emails research- ers in the collaboration exchanged and the queries Collins sent to the physicists who acted for him as “key informants” provide the bulk of the material for Collins’ “real- time” observations of this discovery in the making. At times, Collins finds the community of researchers exasperating and wrong-headed in their, in his view, overly secretive attitudes to their results. But Collins is not a detached witness of the events he describes and analyses. Instead, he is overall a highly enthusias- tic fan of the gravitational wave community. Collins has not sought out for Gravity’s Kiss the kinds of evidence one might have expected a historian to have pursued. Gravity’s Kiss, however, should be read on its terms. It is a work of reportage from an “embedded” sociologist of science with long experience of, and valuable connections in, the gravitational wave community. Along the way, he offers sharp insights into the work- ing of these scientists. Collins proves to be an excellent guide to the operations of a “Big Science” collaboration and the intense scrutiny of, and complicated negotiations around, the “[v]ery interesting event on ER8.” Robert W. Smith University of Alberta [email protected] “Girl-Hours” at the Harvard Observatory The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars. -
Variable Star Classification and Light Curves Manual
Variable Star Classification and Light Curves An AAVSO course for the Carolyn Hurless Online Institute for Continuing Education in Astronomy (CHOICE) This is copyrighted material meant only for official enrollees in this online course. Do not share this document with others. Please do not quote from it without prior permission from the AAVSO. Table of Contents Course Description and Requirements for Completion Chapter One- 1. Introduction . What are variable stars? . The first known variable stars 2. Variable Star Names . Constellation names . Greek letters (Bayer letters) . GCVS naming scheme . Other naming conventions . Naming variable star types 3. The Main Types of variability Extrinsic . Eclipsing . Rotating . Microlensing Intrinsic . Pulsating . Eruptive . Cataclysmic . X-Ray 4. The Variability Tree Chapter Two- 1. Rotating Variables . The Sun . BY Dra stars . RS CVn stars . Rotating ellipsoidal variables 2. Eclipsing Variables . EA . EB . EW . EP . Roche Lobes 1 Chapter Three- 1. Pulsating Variables . Classical Cepheids . Type II Cepheids . RV Tau stars . Delta Sct stars . RR Lyr stars . Miras . Semi-regular stars 2. Eruptive Variables . Young Stellar Objects . T Tau stars . FUOrs . EXOrs . UXOrs . UV Cet stars . Gamma Cas stars . S Dor stars . R CrB stars Chapter Four- 1. Cataclysmic Variables . Dwarf Novae . Novae . Recurrent Novae . Magnetic CVs . Symbiotic Variables . Supernovae 2. Other Variables . Gamma-Ray Bursters . Active Galactic Nuclei 2 Course Description and Requirements for Completion This course is an overview of the types of variable stars most commonly observed by AAVSO observers. We discuss the physical processes behind what makes each type variable and how this is demonstrated in their light curves. Variable star names and nomenclature are placed in a historical context to aid in understanding today’s classification scheme. -
Hardy 1 Williamina Fleming
Hardy 1 Williamina Fleming: Breaking Barriers with A Universe of Glass Isabella L. Hardy Junior Division Individual Performance paper 500 words In the past, women in the sciences were often overlooked, so for National History Day, I chose to focus on an under-recognized female scientist. Early in my research, I found Williamina Paton Fleming. I was surprised I had never encountered her although I had heard of her colleagues, Annie Jump Cannon and Henrietta Leavitt. I have always loved studying the stars and am fascinated by the role of women in astronomy whose important contributions are sometimes forgotten. Williamina Fleming’s unique ability to interpret astronomical photographs changed astronomy in nineteenth- century America and beyond, breaking barriers for scientists and for women. In preliminary research, I located Harvard’s digital scans of Fleming's diary and excellent period photographs, as well as many academic articles about her and other women at the Harvard Observatory. I was also privileged to interview Dr. Lindsay Smith, current Curator of Astronomical Photographs at Harvard. She was extremely helpful in suggesting sources and later reviewed the performance script. Not much is known about Fleming’s early years in Scotland. After her husband abandoned her, she worked for Harvard Observatory Director Edward Pickering, who hired her for the new project to map the night sky. The process involved taking images though telescopes, then mapping all the stars in that small section of sky. Using this process, Fleming discovered stars, novae, and nebulae and encouraged the work of other astronomers, while facilitating many important discoveries. I chose performance to give a voice to a person who has been largely unnoticed. -
Meeting Program
A A S MEETING PROGRAM 211TH MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY WITH THE HIGH ENERGY ASTROPHYSICS DIVISION (HEAD) AND THE HISTORICAL ASTRONOMY DIVISION (HAD) 7-11 JANUARY 2008 AUSTIN, TX All scientific session will be held at the: Austin Convention Center COUNCIL .......................... 2 500 East Cesar Chavez St. Austin, TX 78701 EXHIBITS ........................... 4 FURTHER IN GRATITUDE INFORMATION ............... 6 AAS Paper Sorters SCHEDULE ....................... 7 Rachel Akeson, David Bartlett, Elizabeth Barton, SUNDAY ........................17 Joan Centrella, Jun Cui, Susana Deustua, Tapasi Ghosh, Jennifer Grier, Joe Hahn, Hugh Harris, MONDAY .......................21 Chryssa Kouveliotou, John Martin, Kevin Marvel, Kristen Menou, Brian Patten, Robert Quimby, Chris Springob, Joe Tenn, Dirk Terrell, Dave TUESDAY .......................25 Thompson, Liese van Zee, and Amy Winebarger WEDNESDAY ................77 We would like to thank the THURSDAY ................. 143 following sponsors: FRIDAY ......................... 203 Elsevier Northrop Grumman SATURDAY .................. 241 Lockheed Martin The TABASGO Foundation AUTHOR INDEX ........ 242 AAS COUNCIL J. Craig Wheeler Univ. of Texas President (6/2006-6/2008) John P. Huchra Harvard-Smithsonian, President-Elect CfA (6/2007-6/2008) Paul Vanden Bout NRAO Vice-President (6/2005-6/2008) Robert W. O’Connell Univ. of Virginia Vice-President (6/2006-6/2009) Lee W. Hartman Univ. of Michigan Vice-President (6/2007-6/2010) John Graham CIW Secretary (6/2004-6/2010) OFFICERS Hervey (Peter) STScI Treasurer Stockman (6/2005-6/2008) Timothy F. Slater Univ. of Arizona Education Officer (6/2006-6/2009) Mike A’Hearn Univ. of Maryland Pub. Board Chair (6/2005-6/2008) Kevin Marvel AAS Executive Officer (6/2006-Present) Gary J. Ferland Univ. of Kentucky (6/2007-6/2008) Suzanne Hawley Univ.