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The Comet's Tale, and Therefore the Object As a Whole Would the Section Director Nick James Highlighted Have a Low Surface Brightness
1 Diebold Schilling, Disaster in connection with two comets sighted in 1456, Lucerne Chronicle, 1513 (Wikimedia Commons) THE COMET’S TALE Comet Section – British Astronomical Association Journal – Number 38 2019 June britastro.org/comet Evolution of the comet C/2016 R2 (PANSTARRS) along a total of ten days on January 2018. Composition of pictures taken with a zoom lens from Teide Observatory in Canary Islands. J.J Chambó Bris 2 Table of Contents Contents Author Page 1 Director’s Welcome Nick James 3 Section Director 2 Melvyn Taylor’s Alex Pratt 6 Observations of Comet C/1995 01 (Hale-Bopp) 3 The Enigma of Neil Norman 9 Comet Encke 4 Setting up the David Swan 14 C*Hyperstar for Imaging Comets 5 Comet Software Owen Brazell 19 6 Pro-Am José Joaquín Chambó Bris 25 Astrophotography of Comets 7 Elizabeth Roemer: A Denis Buczynski 28 Consummate Comet Section Secretary Observer 8 Historical Cometary Amar A Sharma 37 Observations in India: Part 2 – Mughal Empire 16th and 17th Century 9 Dr Reginald Denis Buczynski 42 Waterfield and His Section Secretary Medals 10 Contacts 45 Picture Gallery Please note that copyright 46 of all images belongs with the Observer 3 1 From the Director – Nick James I hope you enjoy reading this issue of the We have had a couple of relatively bright Comet’s Tale. Many thanks to Janice but diffuse comets through the winter and McClean for editing this issue and to Denis there are plenty of images of Buczynski for soliciting contributions. 46P/Wirtanen and C/2018 Y1 (Iwamoto) Thanks also to the section committee for in our archive. -
Luminous Blue Variables
Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs. -
SHELL BURNING STARS: Red Giants and Red Supergiants
SHELL BURNING STARS: Red Giants and Red Supergiants There is a large variety of stellar models which have a distinct core – envelope structure. While any main sequence star, or any white dwarf, may be well approximated with a single polytropic model, the stars with the core – envelope structure may be approximated with a composite polytrope: one for the core, another for the envelope, with a very large difference in the “K” constants between the two. This is a consequence of a very large difference in the specific entropies between the core and the envelope. The original reason for the difference is due to a jump in chemical composition. For example, the core may have no hydrogen, and mostly helium, while the envelope may be hydrogen rich. As a result, there is a nuclear burning shell at the bottom of the envelope; hydrogen burning shell in our example. The heat generated in the shell is diffusing out with radiation, and keeps the entropy very high throughout the envelope. The core – envelope structure is most pronounced when the core is degenerate, and its specific entropy near zero. It is supported against its own gravity with the non-thermal pressure of degenerate electron gas, while all stellar luminosity, and all entropy for the envelope, are provided by the shell source. A common property of stars with well developed core – envelope structure is not only a very large jump in specific entropy but also a very large difference in pressure between the center, Pc, the shell, Psh, and the photosphere, Pph. Of course, the two characteristics are closely related to each other. -
Temperature, Mass and Size of Stars
Title Astro100 Lecture 13, March 25 Temperature, Mass and Size of Stars http://www.astro.umass.edu/~myun/teaching/a100/longlecture13.html Also, http://www.astro.columbia.edu/~archung/labs/spring2002/spring2002.html (Lab 1, 2, 3) Goal Goal: To learn how to measure various properties of stars 9 What properties of stars can astronomers learn from stellar spectra? Î Chemical composition, surface temperature 9 How useful are binary stars for astronomers? Î Mass 9 What is Stefan-Boltzmann Law? Î Luminosity, size, temperature 9 What is the Hertzsprung-Russell Diagram? Î Distance and Age Temp1 Stellar Spectra Spectrum: light separated and spread out by wavelength using a prism or a grating BUT! Stellar spectra are not continuous… Temp2 Stellar Spectra Photons from inside of higher temperature get absorbed by the cool stellar atmosphere, resulting in “absorption lines” At which wavelengths we see these lines depends on the chemical composition and physical state of the gas Temp3 Stellar Spectra Using the most prominent absorption line (hydrogen), Temp4 Stellar Spectra Measuring the intensities at different wavelength, Intensity Wavelength Wien’s Law: λpeak= 2900/T(K) µm The hotter the blackbody the more energy emitted per unit area at all wavelengths. The peak emission from the blackbody moves to shorter wavelengths as the T increases (Wien's law). Temp5 Stellar Spectra Re-ordering the stellar spectra with the temperature Temp-summary Stellar Spectra From stellar spectra… Surface temperature (Wien’s Law), also chemical composition in the stellar -
Book of Abstracts
UDC 520/524(048) ISBN 978-86-80019-55-0 VIII SERBIAN-BULGARIAN ASTRONOMICAL CONFERENCE Leskovac, Serbia, May 8-12, 2012 BOOK OF ABSTRACTS Eds. Milan S. Dimitrijević and Milcho K. Tsvetkov BELGRADE 2012 SCIENTIFIC COMMITTEE LOCAL ORGANIZING COMMITTEE Milan S. Dimitrijević (Co-chairman) Milan S. Dimitrijević (Co-chairman) Milcho K. Tsvetkov (Co-chairman) Žarko Mijajlović (Co-chairman) Žarko Mijajlović (Co-vice chairman) Ognyan Kounchev (Co-vice Chairman) Scientific secretary: Tanyu Bonev Andjelka Kovačević Dimo Dimov Dragana Ilić Members: Darko Jevremović Luka Č. Popović Predrag Jovanović Darko Jevremović Andjelka Kovačević Nadežda Pejović Jelena Kovačević Petko Nedialkov Jelena Kovačević Marko Stalevski Nadežda Pejović Luka Č. Popović Tanja Milovanov Miodrag Dačić Zoran Simić Katya Tsvetkova Zoran Simić Dejan Urošević Under the auspices of Serbian Ministry of Education and Science Bulgarian Academy of Sciences ORGANIZERS: Society of Astronomers of Serbia and Astronomical Observatory Institute of Astronomy with National Astronomical Observarory, BAS Co-organizers: Faculty of Mathematics and Department of Astronomy, University of Belgrade Institute of Mathematics and Informatics of the Bulgarian Academy of Sciences Department of Astronomy, Faculty of Physics, Sofia University ''St. Kliment Ohridski' On the front cover: Panorama of the town of Leskovac On the back cover: A forest on a secret planet, author Vladimir M. Dimitrijević Text arrangement by computer: Tatjana Milovanov Published and copyright © by Serbian Astronomical Society and Astronomical Observatory, Belgrade, Volgina 7, 11060 Belgrade, Serbia Financially supported by the Ministry of Education and Science of Serbia __________________________________________________________________ Production: “BS PRINT”, Jurija Gagarina 29v, Novi Beograd, in 100 copies UDC 520/524(048) ISBN 978-86-80019-55-0 VIII SERBIAN-BULGARIAN ASTRONOMICAL CONFERENCE Leskovac, Serbia, May 8-12, 2012 BOOK OF ABSTRACTS Eds. -
Year XIX, Supplement Ethnographic Study And/Or a Theoretical Survey of a Their Position in the Article Should Be Clearly Indicated
III. TITLES OF ARTICLES DRU[TVO ANTROPOLOGOV SLOVENIJE The journal of the Slovene Anthropological Society Titles (in English and Slovene) must be short, informa- SLOVENE ANTHROPOLOGICAL SOCIETY Anthropological Notebooks welcomes the submis- tive, and understandable. The title should be followed sion of papers from the field of anthropology and by the name of the author(s), their position, institutional related disciplines. Submissions are considered for affiliation, and if possible, by e-mail address. publication on the understanding that the paper is not currently under consideration for publication IV. ABSTRACT AND KEYWORDS elsewhere. It is the responsibility of the author to The abstract must give concise information about the obtain permission for using any previously published objective, the method used, the results obtained, and material. Please submit your manuscript as an e-mail the conclusions. Authors are asked to enclose in English attachment on [email protected] and enclose your contact information: name, position, and Slovene an abstract of 100 – 200 words followed institutional affiliation, address, phone number, and by three to five keywords. They must reflect the field of e-mail address. research covered in the article. English abstract should be placed at the beginning of an article and the Slovene one after the references at the end. V. NOTES A N T H R O P O L O G I C A L INSTRUCTIONS Notes should also be double-spaced and used sparingly. They must be numbered consecutively throughout the text and assembled at the end of the article just before references. VI. QUOTATIONS Short quotations (less than 30 words) should be placed in single quotation marks with double marks for quotations within quotations. -
Mathematics in African History and Cultures
Paulus Gerdes & Ahmed Djebbar MATHEMATICS IN AFRICAN HISTORY AND CULTURES: AN ANNOTATED BIBLIOGRAPHY African Mathematical Union Commission on the History of Mathematics in Africa (AMUCHMA) Mathematics in African History and Cultures Second edition, 2007 First edition: African Mathematical Union, Cape Town, South Africa, 2004 ISBN: 978-1-4303-1537-7 Published by Lulu. Copyright © 2007 by Paulus Gerdes & Ahmed Djebbar Authors Paulus Gerdes Research Centre for Mathematics, Culture and Education, C.P. 915, Maputo, Mozambique E-mail: [email protected] Ahmed Djebbar Département de mathématiques, Bt. M 2, Université de Lille 1, 59655 Villeneuve D’Asq Cedex, France E-mail: [email protected], [email protected] Cover design inspired by a pattern on a mat woven in the 19th century by a Yombe woman from the Lower Congo area (Cf. GER-04b, p. 96). 2 Table of contents page Preface by the President of the African 7 Mathematical Union (Prof. Jan Persens) Introduction 9 Introduction to the new edition 14 Bibliography A 15 B 43 C 65 D 77 E 105 F 115 G 121 H 162 I 173 J 179 K 182 L 194 M 207 N 223 O 228 P 234 R 241 S 252 T 274 U 281 V 283 3 Mathematics in African History and Cultures page W 290 Y 296 Z 298 Appendices 1 On mathematicians of African descent / 307 Diaspora 2 Publications by Africans on the History of 313 Mathematics outside Africa (including reviews of these publications) 3 On Time-reckoning and Astronomy in 317 African History and Cultures 4 String figures in Africa 338 5 Examples of other Mathematical Books and 343 -
Mass-Radius Relations for Massive White Dwarf Stars
A&A 441, 689–694 (2005) Astronomy DOI: 10.1051/0004-6361:20052996 & c ESO 2005 Astrophysics Mass-radius relations for massive white dwarf stars L. G. Althaus1,, E. García-Berro1,2, J. Isern2,3, and A. H. Córsico4,5, 1 Departament de Física Aplicada, Universitat Politècnica de Catalunya, Av. del Canal Olímpic, s/n, 08860 Castelldefels, Spain e-mail: [leandro;garcia]@fa.upc.es 2 Institut d’Estudis Espacials de Catalunya, Ed. Nexus, c/Gran Capità 2, 08034 Barcelona, Spain e-mail: [email protected] 3 Institut de Ciències de l’Espai, C.S.I.C., Campus UAB, Facultat de Ciències, Torre C-5, 08193 Bellaterra, Spain 4 Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata, Argentina e-mail: [email protected] 5 Instituto de Astrofísica La Plata, IALP, CONICET, Argentina Received 4 March 2005 / Accepted 18 July 2005 Abstract. We present detailed theoretical mass-radius relations for massive white dwarf stars with oxygen-neon cores. This work is motivated by recent observational evidence about the existence of white dwarf stars with very high surface gravities. Our results are based on evolutionary calculations that take into account the chemical composition expected from the evolu- tionary history of massive white dwarf progenitors. We present theoretical mass-radius relations for stellar mass values ranging from1.06to1.30 M with a step of 0.02 M and effective temperatures from 150 000 K to ≈5000 K. A novel aspect predicted by our calculations is that the mass-radius relation for the most massive white dwarfs exhibits a marked dependence on the neutrino luminosity. -
Serbian Astronomical Works in the Virtual Library of the Faculty of Mathematics in Belgrade
Proceedings of the VII Bulgarian-Serbian Astronomical Conference (VII BSAC) Chepelare, Bulgaria, June 1-4, 2010, Editors: M. K. Tsvetkov, M. S. Dimitrijević, K. Tsvetkova, O. Kounchev, Ž. Mijajlović Publ. Astron. Soc. “Rudjer Bošković” No 11, 2012, 311-323 SERBIAN ASTRONOMICAL WORKS IN THE VIRTUAL LIBRARY OF THE FACULTY OF MATHEMATICS IN BELGRADE NADEŽDA PEJOVIĆ1, ŽARKO MIJAJLOVIĆ1, ALEKSANDAR VALJAREVIĆ2, GORAN DAMLJANOVIĆ3 1Faculty of Mathematics, Univ. of Belgrade, Serbia 2Faculty of Science, Univ. of Priština situated at Kosovska Mitrovica, Serbia 3Astronomical Observatory in Belgrade, Belgrade, Serbia E-mail: [email protected], [email protected], [email protected], [email protected] Abstract. The Virtual Library of the Faculty of Mathematics, http://elibrary.matf.bg.ac.rs, contains more than 50 digitized books on astronomy written by Serbian scientists. This article presents a selection of books written in the 18th and 19th century by the authors: Ruđer Bošković, Zaharije Orfelin, Atanasije Stojković, Đorđe Stanojević, Milan Andonović and Kosta Stojanović. For each of these authors a short biography is included. INTRODUCTION The Virtual Library of the Faculty of Mathematics is the largest database of digitized texts in Serbia which is open for public use. At the time of writing this article, it contains nearly 1500 books mostly in mathematical sciences of old Serbian scientists (e.g. N. Pejović, 2009). Important collections in this library are a collection of 360 doctoral dissertations in mathematical science, most of them defended at the Faculty of Mathematics of the University of Belgrade and rare books from the 18th and 19th century. Most of these books are rather rare; some of them exist only in one copy and in fact are unavailable to the general public. -
A Review on Substellar Objects Below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs Or What?
geosciences Review A Review on Substellar Objects below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs or What? José A. Caballero Centro de Astrobiología (CSIC-INTA), ESAC, Camino Bajo del Castillo s/n, E-28692 Villanueva de la Cañada, Madrid, Spain; [email protected] Received: 23 August 2018; Accepted: 10 September 2018; Published: 28 September 2018 Abstract: “Free-floating, non-deuterium-burning, substellar objects” are isolated bodies of a few Jupiter masses found in very young open clusters and associations, nearby young moving groups, and in the immediate vicinity of the Sun. They are neither brown dwarfs nor planets. In this paper, their nomenclature, history of discovery, sites of detection, formation mechanisms, and future directions of research are reviewed. Most free-floating, non-deuterium-burning, substellar objects share the same formation mechanism as low-mass stars and brown dwarfs, but there are still a few caveats, such as the value of the opacity mass limit, the minimum mass at which an isolated body can form via turbulent fragmentation from a cloud. The least massive free-floating substellar objects found to date have masses of about 0.004 Msol, but current and future surveys should aim at breaking this record. For that, we may need LSST, Euclid and WFIRST. Keywords: planetary systems; stars: brown dwarfs; stars: low mass; galaxy: solar neighborhood; galaxy: open clusters and associations 1. Introduction I can’t answer why (I’m not a gangstar) But I can tell you how (I’m not a flam star) We were born upside-down (I’m a star’s star) Born the wrong way ’round (I’m not a white star) I’m a blackstar, I’m not a gangstar I’m a blackstar, I’m a blackstar I’m not a pornstar, I’m not a wandering star I’m a blackstar, I’m a blackstar Blackstar, F (2016), David Bowie The tenth star of George van Biesbroeck’s catalogue of high, common, proper motion companions, vB 10, was from the end of the Second World War to the early 1980s, and had an entry on the least massive star known [1–3]. -
The Connection Between Galaxy Stellar Masses and Dark Matter
The Connection Between Galaxy Stellar Masses and Dark Matter Halo Masses: Constraints from Semi-Analytic Modeling and Correlation Functions by Catherine E. White A dissertation submitted to The Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy. Baltimore, Maryland August, 2016 c Catherine E. White 2016 ⃝ All rights reserved Abstract One of the basic observations that galaxy formation models try to reproduce is the buildup of stellar mass in dark matter halos, generally characterized by the stellar mass-halo mass relation, M? (Mhalo). Models have difficulty matching the < 11 observed M? (Mhalo): modeled low mass galaxies (Mhalo 10 M ) form their stars ∼ ⊙ significantly earlier than observations suggest. Our goal in this thesis is twofold: first, work with a well-tested semi-analytic model of galaxy formation to explore the physics needed to match existing measurements of the M? (Mhalo) relation for low mass galaxies and second, use correlation functions to place additional constraints on M? (Mhalo). For the first project, we introduce idealized physical prescriptions into the semi-analytic model to test the effects of (1) more efficient supernova feedback with a higher mass-loading factor for low mass galaxies at higher redshifts, (2) less efficient star formation with longer star formation timescales at higher redshift, or (3) less efficient gas accretion with longer infall timescales for lower mass galaxies. In addition to M? (Mhalo), we examine cold gas fractions, star formation rates, and metallicities to characterize the secondary effects of these prescriptions. ii ABSTRACT The technique of abundance matching has been widely used to estimate M? (Mhalo) at high redshift, and in principle, clustering measurements provide a powerful inde- pendent means to derive this relation. -
121012-AAS-221 Program-14-ALL, Page 253 @ Preflight
221ST MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY 6-10 January 2013 LONG BEACH, CALIFORNIA Scientific sessions will be held at the: Long Beach Convention Center 300 E. Ocean Blvd. COUNCIL.......................... 2 Long Beach, CA 90802 AAS Paper Sorters EXHIBITORS..................... 4 Aubra Anthony ATTENDEE Alan Boss SERVICES.......................... 9 Blaise Canzian Joanna Corby SCHEDULE.....................12 Rupert Croft Shantanu Desai SATURDAY.....................28 Rick Fienberg Bernhard Fleck SUNDAY..........................30 Erika Grundstrom Nimish P. Hathi MONDAY........................37 Ann Hornschemeier Suzanne H. Jacoby TUESDAY........................98 Bethany Johns Sebastien Lepine WEDNESDAY.............. 158 Katharina Lodders Kevin Marvel THURSDAY.................. 213 Karen Masters Bryan Miller AUTHOR INDEX ........ 245 Nancy Morrison Judit Ries Michael Rutkowski Allyn Smith Joe Tenn Session Numbering Key 100’s Monday 200’s Tuesday 300’s Wednesday 400’s Thursday Sessions are numbered in the Program Book by day and time. Changes after 27 November 2012 are included only in the online program materials. 1 AAS Officers & Councilors Officers Councilors President (2012-2014) (2009-2012) David J. Helfand Quest Univ. Canada Edward F. Guinan Villanova Univ. [email protected] [email protected] PAST President (2012-2013) Patricia Knezek NOAO/WIYN Observatory Debra Elmegreen Vassar College [email protected] [email protected] Robert Mathieu Univ. of Wisconsin Vice President (2009-2015) [email protected] Paula Szkody University of Washington [email protected] (2011-2014) Bruce Balick Univ. of Washington Vice-President (2010-2013) [email protected] Nicholas B. Suntzeff Texas A&M Univ. suntzeff@aas.org Eileen D. Friel Boston Univ. [email protected] Vice President (2011-2014) Edward B. Churchwell Univ. of Wisconsin Angela Speck Univ. of Missouri [email protected] [email protected] Treasurer (2011-2014) (2012-2015) Hervey (Peter) Stockman STScI Nancy S.