IAU Xxiind General Assembly -The Hague 1994 Editor: SETH SHOSTAK Associate Editor: RENÉ GENEE No
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Helium-Star Mass Loss and Its Implications for Black-Hole
Helium-Star Mass Loss and its Implications for Black-Hole Formation and Supernova Progenitors Onno R. Pols1,2 and Jasinta D.M. Dewi3,4 1 Department of Mathematics, PO Box 28M, Monash University, Vic 3800, Australia 2 Astronomical Institute, Postbus 80000, 3508 TA Utrecht, The Netherlands [email protected] 3 Astronomical Institute, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands [email protected] 4 Bosscha Observatory and Department of Astronomy, Lembang 40391, Bandung, Indonesia Abstract Recently the observationally derived stellar-wind mass-loss rates for Wolf- Rayet stars, or massive naked helium stars, have been revised downwards by a substantial amount. We present evolutionary calculations of helium stars incor- porating such revised mass-loss rates, as well as mass transfer to a close compact binary companion. Our models reach final masses well in excess of 10 M⊙, con- sistent with the observed masses of black holes in X-ray binaries. This resolves the discrepancy found with previously assumed high mass-loss rates between the final masses of stars which spend most of their helium-burning lifetime as Wolf- Rayet stars (∼ 3 M⊙) and the minimum observed black hole masses (6 M⊙). Our arXiv:astro-ph/0203308v1 19 Mar 2002 calculations also suggest that there are two distinct classes of progenitors for Type Ic supernovae: one with very large initial masses (∼> 35 M⊙), which are still massive when they explode and leave black hole remnants, and one with moderate initial masses (∼ 12 − 20 M⊙) undergoing binary interaction, which end up with small pre-explosion masses and leave neutron star remnants. -
Summer Constellations
Night Sky 101: Summer Constellations The Summer Triangle Photo Credit: Smoky Mountain Astronomical Society The Summer Triangle is made up of three bright stars—Altair, in the constellation Aquila (the eagle), Deneb in Cygnus (the swan), and Vega Lyra (the lyre, or harp). Also called “The Northern Cross” or “The Backbone of the Milky Way,” Cygnus is a horizontal cross of five bright stars. In very dark skies, Cygnus helps viewers find the Milky Way. Albireo, the last star in Cygnus’s tail, is actually made up of two stars (a binary star). The separate stars can be seen with a 30 power telescope. The Ring Nebula, part of the constellation Lyra, can also be seen with this magnification. In Japanese mythology, Vega, the celestial princess and goddess, fell in love Altair. Her father did not approve of Altair, since he was a mortal. They were forbidden from seeing each other. The two lovers were placed in the sky, where they were separated by the Celestial River, repre- sented by the Milky Way. According to the legend, once a year, a bridge of magpies form, rep- resented by Cygnus, to reunite the lovers. Photo credit: Unknown Scorpius Also called Scorpio, Scorpius is one of the 12 Zodiac constellations, which are used in reading horoscopes. Scorpius represents those born during October 23 to November 21. Scorpio is easy to spot in the summer sky. It is made up of a long string bright stars, which are visible in most lights, especially Antares, because of its distinctly red color. Antares is about 850 times bigger than our sun and is a red giant. -
Constellations with Prominent Stars That Can Be Found Near the Meridian at 10 Pm on January 15
ONSTELLATIONS C Altitude Ruler The rotation of the Earth on its axis causes the stars to rise and set each evening. In addition, the orbit of the Earth around the Sun places different regions of the sky in our Horizon night-time view. The PLANISPHERE is an extremely useful tool for finding stars and 10 constellation in the sky, depicting not only what is currently in the sky but it also allows the 20 prediction of the rising and setting times of various celestial objects. 30 THE LAYOUT OF THE PLANISPHERE 40 50 The outer circumference of the dark blue circular disk (which is called the star wheel) you’ll notice that the wheel is divided into the 12 months, and that each month is divided into 60 individual dates. The star wheel rotates about the brass fastener, which represents the 70 North Celestial Pole. The frame of the planisphere has times along the outer edge. 80 Holding the planisphere on the southern corner you'll see "midnight" at the top. Moving Zenith counterclockwise, notice how the hours progress, through 1 AM, 2 AM, and so on through "noon" at the bottom. The hours then proceed through the afternoon and evening (1 PM, 2 PM, etc.) back toward midnight. Once you have the wheel set properly for the correct time and day, the displayed part represents what you see if you stand with the star and planet locator held directly over your head with the brass fastener toward the north. (Notice that the compass directions are also written on the corners of the frame.) Of course, you don't have to actually stand that way to make use of the Star and Planet Locator--this is just a description to help you understand what is displayed. -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
Fifi'; 11( from the Editor
S P R I N G 1 9 9 4 ammo CAN HE TRADITI OF HONESTY * SURVIVE DAY'S WORLD? fifi'; 11( From The Editor Rhode S (ISSN 40891-6446) is (From left) published tour times a year in spring, summer, Executive fall and winter by Rhodes College, 2000 N. Editor Helen Norman, Parkway, Memphis, TN 38112-1690. It is pub- Contributing lished as a service to all alumni, students, par- Editor Susan ents, faculty, staff and friends of the college. McLain Sullivan, Art Spring 1994 —Volume 1, Number I. Second Director Trey class postage paid at Memphis, Tennessee and Clark '89, additional mailing offices. and Editor Martha Hunter EXECUTIVE EDITOR: Helen Watkins Norman Shepard '66. EDITOR: Martha Hunter Shepard '66 Welcome to Rhodes, the magazine created especially for and about Rhodes Art Director: Trey Clark '89 alumni, parents, friends, faculty, staff and students. CONTRIBUTING EDITOR: Susan McLain Like the Rhodes Today, which it replaces, the magazine will continue to keep Sullivan you informed about what's happening day to day on campus and in the lives of POSTMASTER: Send address changes to: our alumni. But it will also offer you the chance to sample a broader mix of Rhodes, 2000 North Parkway, Memphis, TN 38112-1690. Rhodes-related articles and in greater depth than possible in the former publica- tion. The aim is for Rhodes to be more visually appealing as well, with an up-to- CHANGE OF ADDRESS: Please mail the complet- ed form below and label from this issue of Rhodes date design (for which we thank Memphis designer Eddie Tucker) and an ample to: Alumni Office, Rhodes College, 2000 North serving of color photography. -
Arxiv:0809.1275V2
How eccentric orbital solutions can hide planetary systems in 2:1 resonant orbits Guillem Anglada-Escud´e1, Mercedes L´opez-Morales1,2, John E. Chambers1 [email protected], [email protected], [email protected] ABSTRACT The Doppler technique measures the reflex radial motion of a star induced by the presence of companions and is the most successful method to detect ex- oplanets. If several planets are present, their signals will appear combined in the radial motion of the star, leading to potential misinterpretations of the data. Specifically, two planets in 2:1 resonant orbits can mimic the signal of a sin- gle planet in an eccentric orbit. We quantify the implications of this statistical degeneracy for a representative sample of the reported single exoplanets with available datasets, finding that 1) around 35% percent of the published eccentric one-planet solutions are statistically indistinguishible from planetary systems in 2:1 orbital resonance, 2) another 40% cannot be statistically distinguished from a circular orbital solution and 3) planets with masses comparable to Earth could be hidden in known orbital solutions of eccentric super-Earths and Neptune mass planets. Subject headings: Exoplanets – Orbital dynamics – Planet detection – Doppler method arXiv:0809.1275v2 [astro-ph] 25 Nov 2009 Introduction Most of the +300 exoplanets found to date have been discovered using the Doppler tech- nique, which measures the reflex motion of the host star induced by the planets (Mayor & Queloz 1995; Marcy & Butler 1996). The diverse characteristics of these exoplanets are somewhat surprising. Many of them are similar in mass to Jupiter, but orbit much closer to their 1Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Rd. -
Mobility Statistics and Automated Hazard Mapping for Debris Flows and Rock Avalanches
Mobility Statistics and Automated Hazard Mapping for Debris Flows and Rock Avalanches Scientific Investigations Report 2007–5276 Version 1.1 U.S. Department of the Interior U.S. Geological Survey Mobility Statistics and Automated Hazard Mapping for Debris Flows and Rock Avalanches By Julia P. Griswold and Richard M. Iverson Scientific Investigations Report 2007–5276 Version 1.1 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director U.S. Geological Survey, Reston, Virginia: 2008 Revised 2014 This report and any updates to it are available at: http://pubs.usgs.gov/sir/2007/5276/ For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS--the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Griswold, J.P., and Iverson, R.M., 2008, Mobility statistics and automated hazard mapping for debris flows and rock avalanches (ver. 1.1, April 2014): U.S. Geological Survey Scientific Investigations Report 2007-5276, 59 p. Manuscript approved for publication, December 12, 2007 Text edited by Tracey L. -
Dirk Brouwer
NATIONAL ACADEMY OF SCIENCES D I R K B R O U W ER 1902—1966 A Biographical Memoir by G . M . C LEMENCE Any opinions expressed in this memoir are those of the author(s) and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoir COPYRIGHT 1970 NATIONAL ACADEMY OF SCIENCES WASHINGTON D.C. DIRK BROUWER September 1, 1902-January 31, 1966 BY G. M. CLEMENCE IRK BROUWER, who contributed more to dynamical astron- D omy than any other astronomer of his time, died on January 31, 1966, after a week in hospital; his death was occa- sioned by an acute disorder of the heart. He is survived by his widow and an only son, James. Brouwer was born in Rotterdam, the Netherlands, on September 1, 1902, the son of a civil service employee. As a stu- dent in the University of Leiden he studied mathematics and astronomy, coming under the influence of Willem de Sitter, who in his own day was the dean of that branch of astronomy in which Brouwer was to do most of his work. Receiving the Ph.D. degree in 1927 under de Sitter, Brouwer came to the United States as a fellow of the International Education Board, spending a year at the University of California in Berkeley and at Yale University, where he was to remain the rest of his life. His initial appointment at Yale was in 1928 as research as- sistant to Ernest W. Brown, who was then the greatest living authority on the motion of the moon. -
Anton Pannekoek: Ways of Viewing Science and Society
STUDIES IN THE HISTORY OF KNOWLEDGE Tai, Van der Steen & Van Dongen (eds) Dongen & Van Steen der Van Tai, Edited by Chaokang Tai, Bart van der Steen, and Jeroen van Dongen Anton Pannekoek: Ways of Viewing Science and Society Ways of Viewing ScienceWays and Society Anton Pannekoek: Anton Pannekoek: Ways of Viewing Science and Society Studies in the History of Knowledge This book series publishes leading volumes that study the history of knowledge in its cultural context. It aspires to offer accounts that cut across disciplinary and geographical boundaries, while being sensitive to how institutional circumstances and different scales of time shape the making of knowledge. Series Editors Klaas van Berkel, University of Groningen Jeroen van Dongen, University of Amsterdam Anton Pannekoek: Ways of Viewing Science and Society Edited by Chaokang Tai, Bart van der Steen, and Jeroen van Dongen Amsterdam University Press Cover illustration: (Background) Fisheye lens photo of the Zeiss Planetarium Projector of Artis Amsterdam Royal Zoo in action. (Foreground) Fisheye lens photo of a portrait of Anton Pannekoek displayed in the common room of the Anton Pannekoek Institute for Astronomy. Source: Jeronimo Voss Cover design: Coördesign, Leiden Lay-out: Crius Group, Hulshout isbn 978 94 6298 434 9 e-isbn 978 90 4853 500 2 (pdf) doi 10.5117/9789462984349 nur 686 Creative Commons License CC BY NC ND (http://creativecommons.org/licenses/by-nc-nd/3.0) The authors / Amsterdam University Press B.V., Amsterdam 2019 Some rights reserved. Without limiting the rights under copyright reserved above, any part of this book may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording or otherwise). -
Exoplanet Community Report
JPL Publication 09‐3 Exoplanet Community Report Edited by: P. R. Lawson, W. A. Traub and S. C. Unwin National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California March 2009 The work described in this publication was performed at a number of organizations, including the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Publication was provided by the Jet Propulsion Laboratory. Compiling and publication support was provided by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, or the Jet Propulsion Laboratory, California Institute of Technology. © 2009. All rights reserved. The exoplanet community’s top priority is that a line of probeclass missions for exoplanets be established, leading to a flagship mission at the earliest opportunity. iii Contents 1 EXECUTIVE SUMMARY.................................................................................................................. 1 1.1 INTRODUCTION...............................................................................................................................................1 1.2 EXOPLANET FORUM 2008: THE PROCESS OF CONSENSUS BEGINS.....................................................2 -
Cfa in the News ~ Week Ending 3 January 2010
Wolbach Library: CfA in the News ~ Week ending 3 January 2010 1. New social science research from G. Sonnert and co-researchers described, Science Letter, p40, Tuesday, January 5, 2010 2. 2009 in science and medicine, ROGER SCHLUETER, Belleville News Democrat (IL), Sunday, January 3, 2010 3. 'Science, celestial bodies have always inspired humankind', Staff Correspondent, Hindu (India), Tuesday, December 29, 2009 4. Why is Carpenter defending scientists?, The Morning Call, Morning Call (Allentown, PA), FIRST ed, pA25, Sunday, December 27, 2009 5. CORRECTIONS, OPINION BY RYAN FINLEY, ARIZONA DAILY STAR, Arizona Daily Star (AZ), FINAL ed, pA2, Saturday, December 19, 2009 6. We see a 'Super-Earth', TOM BEAL; TOM BEAL, ARIZONA DAILY STAR, Arizona Daily Star, (AZ), FINAL ed, pA1, Thursday, December 17, 2009 Record - 1 DIALOG(R) New social science research from G. Sonnert and co-researchers described, Science Letter, p40, Tuesday, January 5, 2010 TEXT: "In this paper we report on testing the 'rolen model' and 'opportunity-structure' hypotheses about the parents whom scientists mentioned as career influencers. According to the role-model hypothesis, the gender match between scientist and influencer is paramount (for example, women scientists would disproportionately often mention their mothers as career influencers)," scientists writing in the journal Social Studies of Science report (see also ). "According to the opportunity-structure hypothesis, the parent's educational level predicts his/her probability of being mentioned as a career influencer (that ism parents with higher educational levels would be more likely to be named). The examination of a sample of American scientists who had received prestigious postdoctoral fellowships resulted in rejecting the role-model hypothesis and corroborating the opportunity-structure hypothesis. -
Incidental Tables
Sp.-V/AQuan/1999/10/27:16:16 Page 667 Chapter 27 Incidental Tables Alan D. Fiala, William F. Van Altena, Stephen T. Ridgway, and Roger W. Sinnott 27.1 The Julian Date ...................... 667 27.2 Standard Epochs ...................... 668 27.3 Reduction for Precession ................. 669 27.4 Solar Coordinates and Related Quantities ....... 670 27.5 Constellations ....................... 672 27.6 The Messier Objects .................... 674 27.7 Astrometry ......................... 677 27.8 Optical and Infrared Interferometry ........... 687 27.9 The World’s Largest Optical Telescopes ........ 689 27.1 THE JULIAN DATE by A.D. Fiala The Julian Day Number (JD) is a sequential count that begins at Noon 1 Jan. 4713 B.C. Julian Calendar. 27.1.1 Julian Dates of Specific Years Noon 1 Jan. 4713 B.C. = JD 0.0 Noon 1 Jan. 1 B.C. = Noon 1 Jan. 0 A.D. = JD 172 1058.0 Noon 1 Jan. 1 A.D. = JD 172 1424.0 A Modified Julian Day (MJD) is defined as JD − 240 0000.5. Table 27.1 gives the Julian Day of some centennial and decennial dates in the Gregorian Calendar. 667 Sp.-V/AQuan/1999/10/27:16:16 Page 668 668 / 27 INCIDENTAL TABLES Table 27.1. Julian date of selected years in the Gregorian calendar [1, 2]. Julian day at noon (UT) on 0 January, Gregorian calendar Jan. 0.5 JD Jan. 0.5 JD Jan. 0.5 JD Jan. 0.5 JD 1500 226 8923 1910 241 8672 1960 243 6934 2010 245 5197 1600 230 5447 1920 242 2324 1970 244 0587 2020 245 8849 1700 234 1972 1930 242 5977 1980 244 4239 2030 246 2502 1800 237 8496 1940 242 9629 1990 244 7892 2040 246 6154 1900 241 5020 1950 243 3282 2000 245 1544 2050 246 9807 Century years evenly divisible by 400 (e.g., 1600, 2000) are leap years.