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Density Profiles of Populous Star Clusters in the Magellanic Clouds
Density profiles of populous star clusters in the Magellanic Clouds Grigor Nikolov,1,2 Anastasos Dapergolas,3 Mary Kontizas,2 Valeri Golev,1 Maya Belcheva2 1 Department of Astronomy, Faculty of Physics, Sofia University, BG-1164 Sofia, Bulgaria 2 Department of Astrophysics, Astronomy & Mechanics, Faculty of Physics, University of Athens, GR-15783 Athens, Greece 3 IAA, National Observatory of Athens, GR-11810 Athens, Greece [email protected] (Conference poster) Abstract. The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) provide the unique opportunity to study young and populous star clusters. Some of them are elliptical in shape, or are members of a multiple systems, which are almost absent in the Milky Way. We have selected a sample of Magellanic Clouds’ star clusters, some of them candidates of a multiple system components, to investigate them by means of their number density profiles. This approach allows us to determine the radial distribution of the stars of different magnitude. Since the brighter stars have larger masses than the fainter stars, the profiles can be used to trace mass-segregation in the clusters. We have fitted a theoretical model by Elson, Fall & Freeman [1987] to determine the core radius and the concentration of the stars for each magnitude range. Key words: star clusters Профили на плътността на населени звездни купове в Магелановите облаци Григор Николов, Анастасос Даперголас, Мери Контизас, Валери Голев, Мая Белчева Големият и Малкият Магеланови облаци предлагат уникалната възможност за изуча- ване на млади богато населени звездни купове. Някои от тях имат елиптична форма или са членове на двойни системи, каквито се срещат много рядко в Млечния път. -
The Fall of the Youngest Planetary Nebula, Hen3-1357
IOP Publishing Submitted in this form to ApJ 3 Sept 2020 Astrophysical Journal ApJ (XXXX) XXXXXX https://doi.org/XXXX/XXXX The Fall of the Youngest Planetary Nebula, Hen3-1357 Bruce Balick1*, Martín A. Guerrero2, Gerardo Ramos-Larios3 1 Department of Astronomy, University of Washington, Seattle, WA 98195-1580, USA 2 Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía S/N, 18008 Granada, Spain 3 Instituto de Astronomía y Meteorología, Universidad de Guadalajara, 44130 Guadalajara, Mexico *Corresponding author: [email protected] Received xxxxxx Accepted for publication xxxxxx Published xxxxxx Abstract The Stingray Nebula, aka Hen3-1357, went undetected until 1990 when bright nebular lines and radio emission were unexpectedly discovered. We report changes in shape and rapid and secular decreases in its nebular emission-line fluxes based on well calibrated images obtained by the Hubble Space Telescope in 1996, 2000, and 2016. Hen3-1357 is now a “recombination nebula”. Keywords: planetary nebulae: Planetary nebulae (1249), Post-asymptotic giant branch stars (2121), Ionization (2068) 1. Introduction Planetary nebulae (“PNe”) consist of stellar gas ejected in winds from the surfaces of post Asymptotic Branch Giant (“AGB”) stars. The winds systematically expose deeper and much hotter interior stellar layers until stellar energetic ultraviolet (“UV”) begins to ionize the ejected gas. The PN radiates a rich, luminous, and readily detectable set of emission lines (e.g., 6) as electron recombinations with H+ and He+ and optical forbidden lines of N+, O+, O++, S+, etc. These lines become increasingly visible by about a millennium after the winds begin as the central star shifts towards higher temperatures > 40 kK. -
Indian Institute of Astrophysics Academic Report 1997-1998
INDIAN INSTITUTE OF ASTROPHYSICS ACADEMIC REPORT 1997-1998 ecf1ted by: P.Venkatakrishnan Editorial Assmance : Sandra Rajiva Front Cover Radioheliogram of active region obtained from Gauribidanur. Back Cover Lab simulation of optical interferometry. Interferogram produced with seven holes at High Angular Resolution Laboratory. Bangelore. Prned at Vykat Pmta Pvt. Ud.• Aiport Road Cross, Banga/ore 560017 CONTENTS Page Page Governing Council 1 Library 48 Highlights of the year 1997-98 3 Official Language Implementation 48 Sun and the solar system 7 Personnel 49 Stars and stellar systems 17 Appendixes 51 Theoretical Astrophysics 27 A: Publications 5:1 Physics 35 B: HRD Activities 65 Facilities 39 C: Sky Conditions at VBO and Kodaikanal Observatory 67 GOVERNING COUNCIL 1 Prof. B. V. Sreekantan Chairman Prof. Yash Pal Member S. Radhakrishnan Professor Chairman, Steering Committee National Institute of Advanced Studies Inter-University Consortium for Indian Inst.itute of Science Campus Educational Communication Bangalore 560012 New Delhi 110067 Prof. V.S. Ramamurthy Member Prof. 1. B. S. Passil Member Secretary Professor, Department of Science and Technology Centre for Advanced Study in Mathematics New Delhi 110016 Panjab University Chandigarh 160014 Sri Rahul Sarin, lAS Member Joint Secretary and Financial Advisor Prof. H. S. Mani2 Membpr Department. of Science and Technology Director New Delhi 110016 Mehta Research Institute of Mathematirs & Mathematical Physics Prof. J. C. Bhattacharyya2 Member Chhatnag Road, Jhusi 215, Trinity Enclave Allahabad 221506 Old Madras Road Bangalore 560008 Dr. S.K. Sikka Associate Director, Prof. Ramanath Cowsik Member Solid St.ate & Spectroscopy Group, and Director Head, High Pressure Physics Division Indian Institute of Astrophysics BARC, Trombay, Mumbai 400085 Bangalore 560034 Prof. -
THE MAGELLANIC CLOUDS NEWSLETTER an Electronic Publication Dedicated to the Magellanic Clouds, and Astrophysical Phenomena Therein
THE MAGELLANIC CLOUDS NEWSLETTER An electronic publication dedicated to the Magellanic Clouds, and astrophysical phenomena therein No. 141 — 1 June 2016 http://www.astro.keele.ac.uk/MCnews Editor: Jacco van Loon Editorial Dear Colleagues, It is my pleasure to present you the 141st issue of the Magellanic Clouds Newsletter. There is a lot of interest in massive stars, star clusters, supernova remnants and binaries, but also several exciting new results about the large-scale structure of the Magellanic Clouds System. The next issue is planned to be distributed on the 1st of August 2016. Editorially Yours, Jacco van Loon 1 Refereed Journal Papers Non-radial pulsation in first overtone Cepheids of the Small Magellanic Cloud R. Smolec1 and M. Sniegowska´ 2 1Nicolaus Copernicus Astronomical Center, Warsaw, Poland 2Warsaw University Observatory, Warsaw, Poland We analyse photometry for 138 first overtone Cepheids from the Small Magellanic Cloud, in which Optical Gravitational Lensing Experiment team discovered additional variability with period shorter than first overtone period, and period ratios in the (0.60,0.65) range. In the Petersen diagram, these stars form three well-separated sequences. The additional variability cannot correspond to other radial mode. This form of pulsation is still puzzling. We find that amplitude of the additional variability is small, typically 2–4 per cent of the first overtone amplitude, which corresponds to 2–5 mmag. In some stars, we find simultaneously two close periodicities corresponding to two sequences in the Petersen diagram. The most important finding is the detection of power excess at half the frequency of the additional variability (at subharmonic) in 35 per cent of the analysed stars. -
Orders of Magnitude (Length) - Wikipedia
03/08/2018 Orders of magnitude (length) - Wikipedia Orders of magnitude (length) The following are examples of orders of magnitude for different lengths. Contents Overview Detailed list Subatomic Atomic to cellular Cellular to human scale Human to astronomical scale Astronomical less than 10 yoctometres 10 yoctometres 100 yoctometres 1 zeptometre 10 zeptometres 100 zeptometres 1 attometre 10 attometres 100 attometres 1 femtometre 10 femtometres 100 femtometres 1 picometre 10 picometres 100 picometres 1 nanometre 10 nanometres 100 nanometres 1 micrometre 10 micrometres 100 micrometres 1 millimetre 1 centimetre 1 decimetre Conversions Wavelengths Human-defined scales and structures Nature Astronomical 1 metre Conversions https://en.wikipedia.org/wiki/Orders_of_magnitude_(length) 1/44 03/08/2018 Orders of magnitude (length) - Wikipedia Human-defined scales and structures Sports Nature Astronomical 1 decametre Conversions Human-defined scales and structures Sports Nature Astronomical 1 hectometre Conversions Human-defined scales and structures Sports Nature Astronomical 1 kilometre Conversions Human-defined scales and structures Geographical Astronomical 10 kilometres Conversions Sports Human-defined scales and structures Geographical Astronomical 100 kilometres Conversions Human-defined scales and structures Geographical Astronomical 1 megametre Conversions Human-defined scales and structures Sports Geographical Astronomical 10 megametres Conversions Human-defined scales and structures Geographical Astronomical 100 megametres 1 gigametre -
Astronomers Observe Star Reborn in a Flash 13 September 2016
Astronomers observe star reborn in a flash 13 September 2016 astronomers have observed an exception to this rule. "SAO 244567 is one of the rare examples of a star that allows us to witness stellar evolution in real time", explains Nicole Reindl from the University of Leicester, UK, lead author of the study. "Over only twenty years the star has doubled its temperature and it was possible to watch the star ionising its previously ejected envelope, which is now known as the Stingray Nebula." SAO 244567, 2700 light-years from Earth, is the central star of the Stingray Nebula and has been visibly evolving between observations made over the last 45 years. Between 1971 and 2002 the surface temperature of the star skyrocketed by almost 40 000 degrees Celsius. Now new observations made with the Cosmic Origins Spectrograph (COS) on the NASA/ESA Hubble Space Telescope have revealed that SAO 244567 has started to cool and expand. This image of the Stingray nebula, a planetary nebula This is unusual, though not unheard-of, and the 2400 light-years from Earth, was taken with the Wide rapid heating could easily be explained if one Field and Planetary Camera 2 (WFPC2) in 1998. In the assumed that SAO 244567 had an initial mass of 3 centre of the nebula the fast evolving star SAO 244567 to 4 times the mass of the Sun. However, the data is located. Observations made within the last 45 years show that SAO 244567 must have had an original showed that the surface temperature of the star mass similar to that of our Sun. -
Stellar Rotation the Missing Piece in Stellar Physics
Stellar rotation the missing piece in Stellar physics Collaborators: Richard de Grijs (MQ), Licai Deng (NAOC), Chengyuan Li (SYSU), Michael Albrow (UC), Petri Vaisanen (SAAO), Zara Randriamanakoto (SAAO) Weijia Sun (PKU) 07/14/2021 Why stellar rotation is important? Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Matt & Pudritz 2005 Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Maeder & Meynet 2011 Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Rivinius+2013 extended MSTO and split MS Found in Magellanic Clouds clusters rMS bMS NGC 1846 NGC 1856 1.5 Gyr 350 Myr Mackey et al. 2008 Milone et al. 2015 Not only in MC clusters Niederhofer et al. 2015 But also in Galactic OCs Pattern NGC 5822 0.9 Gyr Sun et al. 2019a Cordoni et al. 2018 What causes eMSTO and split MS? • Extended star formation history (eSFH) • Variability • A wide range of stellar rotations What causes eMSTO and split MS? Stellar rotation 300 0.0 250 Gravity darkening 0.5 1.0 200 (mag) 1.5 150 G M 2.0 100 2.5 50 pole-on (i = 0) 3.0 0.2 0.4 0.6 G G (mag) BP ° RP edge-on (i = 90) It’s mainly v sin i that affects the locus of a star in the CMD Georgy et al. -
The Agb Newsletter
THE AGB NEWSLETTER An electronic publication dedicated to Asymptotic Giant Branch stars and related phenomena Official publication of the IAU Working Group on Red Giants and Supergiants No. 279 — 2 October 2020 https://www.astro.keele.ac.uk/AGBnews Editors: Jacco van Loon, Ambra Nanni and Albert Zijlstra Editorial Board (Working Group Organising Committee): Marcelo Miguel Miller Bertolami, Carolyn Doherty, JJ Eldridge, Anibal Garc´ıa-Hern´andez, Josef Hron, Biwei Jiang, Tomasz Kami´nski, John Lattanzio, Emily Levesque, Maria Lugaro, Keiichi Ohnaka, Gioia Rau, Jacco van Loon (Chair) Figure 1: The Rapid Fading of the Youngest Planetary Nebula, Hen 3-1357. Two composite Hubble images of the Sting Ray Nebula taken in 1996 and 2016 in (R:G:B) = (F658N,F656N,F502N) = the emission lines of ([N ii], Hα, [O iii]). Both images are shown with the same absolute intensities in each filter. Nebular emission from Hen3-1357, the youngest planetary nebula (Bobrowsky, 1994, ApJ, 426, L47), unexpectedly appeared sometime during the 1980s (Parthasarathy et al. 1993, A&A, 267, 19). Since then the central star has rapidly faded (e.g., Schaefer & Edwards, 2015, ApJ, 812, 133). The integrated emission fluxes of these three lines in the images above decreased by factors of 0.20, 0.37, and 0.6, respectively, over 20 years. As expected, the rates of fading are much higher in regions of highest emission measure as N+, H+, and O++ recombine. See Balick et al. in this issue. 1 Editorial Dear Colleagues, It is a pleasure to present you the 279th issue of the AGB Newsletter. -
Resolved Massive Cluster Formation at Low and High Redshift Nate Bastian (Liverpool JMU) Stellar Clusters
Resolved Massive Cluster Formation at Low and High Redshift Nate Bastian (Liverpool JMU) Stellar Clusters Type Age Mass Found where star- Open 0 - (3-10) Gyr 100 - 104 Mo formation is happening where star- Young Massive <100 Myr or > 104 Mo formation is Clusters (YMCs) 0 - (1-10) Gyr happening >10 Gyr or Globular > 104 Mo bulge/halo >6 Gyr Nuclear all ages > 105 Mo nucleus Stellar Clusters Type Age Mass Found where star- Open 0 - (3-10) Gyr 100 - 104 Mo formation is happening where star- Young Massive <100 Myr or > 104 Mo formation is Clusters (YMCs) 0 - (1-10) Gyr happening >10 Gyr or Globular > 104 Mo bulge/halo >6 Gyr Nuclear all ages > 105 Mo nucleus Stellar Clusters Type Age Mass Found where star- Open 0 - (3-10) Gyr 100 - 104 Mo formation is happening where star- Young Massive <100 Myr or > 104 Mo formation is Clusters (YMCs) 0 - (1-10) Gyr happening >10 Gyr or Globular > 104 Mo bulge/halo >6 Gyr Nuclear all ages > 105 Mo nucleus Stellar Clusters Type Age Mass Found where star- Open 0 - (3-10) Gyr 100 - 104 Mo formation is happening where star- Young Massive <100 Myr or > 104 Mo formation is Clusters (YMCs) 0 - (1-10) Gyr happening >10 Gyr or Globular > 104 Mo bulge/halo >6 Gyr see recent review by Neumeyer, Seth and Nuclear all ages > 105 Mo nucleus Boeker ARA&A Stellar Clusters Type Age Mass Found where star- Open 0 - (3-10) Gyr 100 - 104 Mo formation is happening where star- Young Massive <100 Myr or > 104 Mo formation is Clusters (YMCs) 0 - (1-10) Gyr happening >10 Gyr or Globular > 104 Mo bulge/halo >6 Gyr see recent review -
Popular Names of Deep Sky (Galaxies,Nebulae and Clusters) Viciana’S List
POPULAR NAMES OF DEEP SKY (GALAXIES,NEBULAE AND CLUSTERS) VICIANA’S LIST 2ª version August 2014 There isn’t any astronomical guide or star chart without a list of popular names of deep sky objects. Given the huge amount of celestial bodies labeled only with a number, the popular names given to them serve as a friendly anchor in a broad and complicated science such as Astronomy The origin of these names is varied. Some of them come from mythology (Pleiades); others from their discoverer; some describe their shape or singularities; (for instance, a rotten egg, because of its odor); and others belong to a constellation (Great Orion Nebula); etc. The real popular names of celestial bodies are those that for some special characteristic, have been inspired by the imagination of astronomers and amateurs. The most complete list is proposed by SEDS (Students for the Exploration and Development of Space). Other sources that have been used to produce this illustrated dictionary are AstroSurf, Wikipedia, Astronomy Picture of the Day, Skymap computer program, Cartes du ciel and a large bibliography of THE NAMES OF THE UNIVERSE. If you know other name of popular deep sky objects and you think it is important to include them in the popular names’ list, please send it to [email protected] with at least three references from different websites. If you have a good photo of some of the deep sky objects, please send it with standard technical specifications and an optional comment. It will be published in the names of the Universe blog. It could also be included in the ILLUSTRATED DICTIONARY OF POPULAR NAMES OF DEEP SKY. -
Arxiv:0905.1328V3
Spitzer SAGE Infrared Photometry of Massive Stars in the Large Magellanic Cloud A. Z. Bonanos1,2, D.L. Massa2, M. Sewilo2, D. J. Lennon2, N. Panagia2,3, L. J. Smith2, M. Meixner2, B. L. Babler4, S. Bracker4, M. R. Meade4, K.D. Gordon2, J.L. Hora5, R. Indebetouw6, B. A. Whitney7 ABSTRACT We present a catalog of 1750 massive stars in the Large Magellanic Cloud, with accurate spectral types compiled from the literature, and a photometric cat- alog for a subset of 1268 of these stars, with the goal of exploring their infrared properties. The photometric catalog consists of stars with infrared counterparts in the Spitzer SAGE survey database, for which we present uniform photometry from 0.3 − 24 µm in the UBVIJHKs+IRAC+MIPS24 bands. The resulting infrared color–magnitude diagrams illustrate that the supergiant B[e], red super- giant and luminous blue variable (LBV) stars are among the brightest infrared point sources in the Large Magellanic Cloud, due to their intrinsic brightness, and at longer wavelengths, due to dust. We detect infrared excesses due to free– free emission among ∼ 900 OB stars, which correlate with luminosity class. We confirm the presence of dust around 10 supergiant B[e] stars, finding the shape of their spectral energy distributions (SEDs) to be very similar, in contrast to 1Giacconi Fellow. 2Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218, USA; bonanos, massa, sewilo, lennon, panagia, lsmith, meixner, [email protected] 3INAF/Osservatorio Astrofisico di Catania, Via S.Sofia 78, I-95123 Catania, Italy; and Supernova Ltd., arXiv:0905.1328v3 [astro-ph.SR] 11 Aug 2009 VGV #131, Northsound Road, Virgin Gorda, British Virgin Islands. -
The Complete Idiot's Guide to Astronomy
00 1981 FM 6/11/01 9:55 AM Page i Astronomy Second Edition by Christopher De Pree and Alan Axelrod A Pearson Education Company 00 1981 FM 6/11/01 9:55 AM Page ii To my girls, Julia, Claire, and Madeleine (CGD) For my stars, Anita and Ian (AA) Copyright © 2001 by The Ian Samuel Group, Inc. All rights reserved. No part of this book shall be reproduced, stored in a retrieval sys- tem, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without written permission from the publisher. No patent liability is as- sumed with respect to the use of the information contained herein. Although every precaution has been taken in the preparation of this book, the publisher and authors assume no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of information contained herein. For information, ad- dress Alpha Books, 201 West 103rd Street, Indianapolis, IN 46290. THE COMPLETE IDIOT’S GUIDE TO and Design are registered trademarks of Pearson Education, Inc. International Standard Book Number:1-5925-7003-8 Library of Congress Catalog Card Number: 2001091092 03020187654321 Interpretation of the printing code: The rightmost number of the first series of num- bers is the year of the book’s printing; the rightmost number of the second series of numbers is the number of the book’s printing. For example, a printing code of 01-1 shows that the first printing occurred in 2001. Printed in the United States of America Note:This publication contains the opinions and ideas of its authors.