Long-Term Spectroscopic Monitoring of the Luminous Blue Variable
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The Rotationally Modulated Polarization of Ξ Boo A
MNRAS 000,1–8 (2018) Preprint 12 February 2019 Compiled using MNRAS LATEX style file v3.0 The Rotationally Modulated Polarization of ξ Boo A Daniel V. Cotton1;2?, Dag Evensberget3, Stephen C. Marsden3, Jeremy Bailey1;2, Jinglin Zhao1, Lucyna Kedziora-Chudczer1;2, Bradley D. Carter3, Kimberly Bott4;5, Aline A. Vidotto6, Pascal Petit7;8, Julien Morin9 and Sandra V. Jeffers10. 1School of Physics, UNSW Sydney, NSW 2052, Australia. 2Australian Centre for Astrobiology, UNSW Sydney, NSW 2052, Australia. 3University of Southern Queensland, Centre for Astrophysics, Springfield, Qld. 4300/Toowoomba, Qld. 4350, Australia. 4University of Washington Astronomy Department, Box 351580, UW Seattle, WA 98195, USA. 5NExSS Virtual Planetary Laboratory, Box 351580, UW Seattle, WA 98195, USA. 6School of Physics, Trinity College Dublin, College Green, Dublin 2, Ireland. 7Université de Toulouse, UPS-OMP, IRAP, Toulouse, France. 8CNRS, Institut de Recherche en Astrophysique et Planetologie, 14, avenue Edouard Belin, F-31400 Toulouse, France. 9LUPM-UMR 5299, CNRS & Université Montpellier, place Eugène Bataillon, 34095 Montpellier Cedex 05, France. 10Institute for Astrophysics, University of Goettingen, Friedrich Hund Platz 1, 37077, Goettingen, Germany. Accepted . Received ; in original form ABSTRACT We have observed the active star ξ Boo A (HD 131156A) with high precision broad- band linear polarimetry contemporaneously with circular spectropolarimetry. We find both signals are modulated by the 6.43 day rotation period of ξ Boo A. The signals from the two techniques are 0.25 out of phase, consistent with the broadband linear po- larization resulting from differential saturation of spectral lines in the global transverse magnetic field. The mean magnitude of the linear polarization signal is ∼4 ppm/G but its structure is complex and the amplitude of the variations suppressed relative to the longitudinal magnetic field. -
An Atlas of Spectra of B6–A2 Hypergiants and Supergiants from 4800 to 6700 Å?
A&A 397, 1035–1042 (2003) Astronomy DOI: 10.1051/0004-6361:20021430 & c ESO 2003 Astrophysics An atlas of spectra of B6–A2 hypergiants and supergiants from 4800 to 6700 Å? E. L. Chentsov1;2,S.V.Ermakov1;2, V.G. Klochkova1;2,V.E.Panchuk1;2, K. S. Bjorkman3, and A. S. Miroshnichenko3;4 1 Special Astrophysical Observatory of the Russian Academy of Sciences, Karachai-Cirkassian Republic, Nizhnij Arkhyz, 369167, Russia 2 Isaac Newton Institute of Chile, SAO Branch 3 Ritter Observatory, Dept. of Physics & Astronomy, University of Toledo, Toledo, OH 43606-3390, USA 4 Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 196140, Saint-Petersburg, Russia Received 20 March 2002 / Accepted 24 September 2002 Abstract. We present an atlas of spectra of 5 emission-line stars: the low-luminosity luminous blue variables (LBVs) HD 168625 and HD 160529, the white hypergiants (and LBV candidates) HD 168607 and AS 314, and the supergiant HD 183143. The spectra were obtained with 2 echelle spectrometers at the 6-m telescope of the Russian Academy of Sciences in the spectral range 4800 to 6700 Å, with a resolution of 0.4 Å. We have identified 380 spectral lines and diffuse interstellar bands within the spectra. Specific spectral features of the objects are described. Key words. stars: emission-line, Be – stars: individual: HD 160529, HD 168607, HD 168625, HD 183143, AS 314 1. Introduction The amplitude of variations in brightness and temperature de- crease as the luminosity decreases. In the least luminous LBVs (M 9 mag), the temperature varies between 12 000– This paper presents a comparative description of the optical bol ∼− spectra of several white hypergiants and supergiants. -
Annual Report 1972
I I ANNUAL REPORT 1972 EUROPEAN SOUTHERN OBSERVATORY ANNUAL REPORT 1972 presented to the Council by the Director-General, Prof. Dr. A. Blaauw, in accordance with article VI, 1 (a) of the ESO Convention Organisation Europeenne pour des Recherches Astronomiques dans 1'Hkmisphtre Austral EUROPEAN SOUTHERN OBSERVATORY Frontispiece: The European Southern Observatory on La Silla mountain. In the foreground the "old camp" of small wooden cabins dating from the first period of settlement on La Silln and now gradually being replaced by more comfortable lodgings. The large dome in the centre contains the Schmidt Telescope. In the background, from left to right, the domes of the Double Astrograph, the Photo- metric (I m) Telescope, the Spectroscopic (1.>2 m) Telescope, and the 50 cm ESO and Copen- hagen Telescopes. In the far rear at right a glimpse of the Hostel and of some of the dormitories. Between the Schmidt Telescope Building and the Double Astrograph the provisional mechanical workshop building. (Viewed from the south east, from a hill between thc existing telescope park and the site for the 3.6 m Telescope.) TABLE OF CONTENTS INTRODUCTION General Developments and Special Events ........................... 5 RESEARCH ACTIVITIES Visiting Astronomers ........................................ 9 Statistics of Telescope Use .................................... 9 Research by Visiting Astronomers .............................. 14 Research by ESO Staff ...................................... 31 Joint Research with Universidad de Chile ...................... -
A Study of Two Open Clusters Containing Wolf-Rayet Stars
A STUDY OF TWO OPEN CLUSTERS CONTAINING WOLF-RAYET STARS by Stephen L. Shorlin A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF ASTRONOlMY AND PHYSICS SAINT MARY'S UMNERSITY MAY 1998 HALIFAX, NOVA SCOTIA Ostephen L. Shorlin, 1998 National Library Bibliothèque nationale I*m of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. nie Wellington Ottawa ON K1A ON4 Ottawa ON KIA ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loau, distribute or seU reproduire, prêter, distribuer ou copies of this thesis in microfoq vendre des copies de cette thèse sous paper or electronic formats. la fome de microfiche/nIm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimes reproduced *out the author's ou autrement reproduits sans son permission. autorisation- Abstract The results of UBV CCD photornetry are presented for a newly discovered open cluster, as well as new photornetry for thirty-seven members of the open cluster HM 1. The new open cluster, to be designated OCL 1104610, has a distance modulus of Vo - l'LIV = 15.5 & 0.2: corresponding to a distance of 12.61::: kpc, and is several Myr old. -
A Constellation of 6 Nanosatellites 3 Countries
1 BRIght Target Explorer: a Constellation of 6 nanosatellites 3 countries AUSTRIA CANADA POLAND u www.tugraz.at u www.brite-constellation.at 2 BRITE-Constellation: operating five nano-satellites to serve one mission picture: pre-launch lab at ISRO India, courtesy of SFL Rainer Kuschnig – University of Technology Graz / University Vienna Rainer Kuschnig, 26 June 2017, EWASS, Prague 3 Why BRITE Constellation ? • Collect time series photometry for some of the brightest stars in the sky, mag(V)<4(..6) with high precision ~0.1-0.5% (mmag)/orbit mean • ~ 15-30 stars per observing field at once 15min/orbit • Measurements in two colors: red and blue (two wavelength well separated ranges) • Time bases of up to 180 days for a single observing campaign Rainer Kuschnig, 26 June 2017, EWASS, Prague 4 BRITE-Constellation: Data sampling Rainer Kuschnig, 26 June 2017, EWASS, Prague 5 BRITE - Constellation 3 countries – 6(5) satellites – ONE MISSION BRITE-CA2 “Montreal” was launched with the same rocket as BRITE-CA1 “Toronto”, but did not separate from the upper stage 83% 5 satellites collect science data Rainer Kuschnig, 26 June 2017, EWASS, Prague 6 Satellite Design – BRITE nano satellites • 20cm cubes mass ~ 7kg • Pre-deployed antennas and booms • Power (peak) 7 Watts • Star tracker • Three-axis attitude control (~1.5 arcminute stability) • UHF (up) and S-Band (down) communication all BRITE satellite have the same design except instrument and star tracker Rainer Kuschnig, 26 June 2017, EWASS, Prague 7 Satellite Design: Instrument • 3 cm aperture • 5 -
Patrick Moore's Practical Astronomy Series
Patrick Moore’s Practical Astronomy Series Other Titles in this Series Navigating the Night Sky Astronomy of the Milky Way How to Identify the Stars and The Observer’s Guide to the Constellations Southern/Northern Sky Parts 1 and 2 Guilherme de Almeida hardcover set Observing and Measuring Visual Mike Inglis Double Stars Astronomy of the Milky Way Bob Argyle (Ed.) Part 1: Observer’s Guide to the Observing Meteors, Comets, Supernovae Northern Sky and other transient Phenomena Mike Inglis Neil Bone Astronomy of the Milky Way Human Vision and The Night Sky Part 2: Observer’s Guide to the How to Improve Your Observing Skills Southern Sky Michael P. Borgia Mike Inglis How to Photograph the Moon and Planets Observing Comets with Your Digital Camera Nick James and Gerald North Tony Buick Telescopes and Techniques Practical Astrophotography An Introduction to Practical Astronomy Jeffrey R. Charles Chris Kitchin Pattern Asterisms Seeing Stars A New Way to Chart the Stars The Night Sky Through Small Telescopes John Chiravalle Chris Kitchin and Robert W. Forrest Deep Sky Observing Photo-guide to the Constellations The Astronomical Tourist A Self-Teaching Guide to Finding Your Steve R. Coe Way Around the Heavens Chris Kitchin Visual Astronomy in the Suburbs A Guide to Spectacular Viewing Solar Observing Techniques Antony Cooke Chris Kitchin Visual Astronomy Under Dark Skies How to Observe the Sun Safely A New Approach to Observing Deep Space Lee Macdonald Antony Cooke The Sun in Eclipse Real Astronomy with Small Telescopes Sir Patrick Moore and Michael Maunder Step-by-Step Activities for Discovery Transit Michael K. -
The Spitzer Atlas of Stellar Spectra (Sass)
The Astrophysical Journal Supplement Series, 191:301–339, 2010 December doi:10.1088/0067-0049/191/2/301 C 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE SPITZER ATLAS OF STELLAR SPECTRA (SASS) David R. Ardila1, Schuyler D. Van Dyk2, Wojciech Makowiecki2, John Stauffer2, Inseok Song3, Jeonghee Rho2,4, Sergio Fajardo-Acosta2,5, D. W. Hoard2, and Stefanie Wachter2 1 NASA Herschel Science Center, California Institute of Technology, Mail Code 100-22, Pasadena, CA 91125, USA; [email protected] 2 Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125, USA 3 Department of Physics and Astronomy, University of Georgia at Athens, GA 30602-2451, USA 4 SOFIA Science Center, USRA/NASA Ames Research Center, Moffet Field, CA 94035, USA 5 WISE Science Data Center, California Institute of Technology, Pasadena, CA 91125, USA Received 2010 June 17; accepted 2010 October 22; published 2010 November 30 ABSTRACT We present the Spitzer Atlas of Stellar Spectra, which includes 159 stellar spectra (5–32 μm; R ∼ 100) taken with the Infrared Spectrograph on the Spitzer Space Telescope. This Atlas gathers representative spectra of a broad section of the Hertzsprung–Russell diagram, intended to serve as a general stellar spectral reference in the mid-infrared. It includes stars from all luminosity classes, as well as Wolf-Rayet (WR) objects. Furthermore, it includes some objects of intrinsic interest, such as blue stragglers and certain pulsating variables. All of the spectra have been uniformly reduced, and all are available online. For dwarfs and giants, the spectra of early-type objects are relatively featureless, characterized by the presence of hydrogen lines in A spectral types. -
The Electric Sun Hypothesis
Basics of astrophysics revisited. II. Mass- luminosity- rotation relation for F, A, B, O and WR class stars Edgars Alksnis [email protected] Small volume statistics show, that luminosity of bright stars is proportional to their angular momentums of rotation when certain relation between stellar mass and stellar rotation speed is reached. Cause should be outside of standard stellar model. Concept allows strengthen hypotheses of 1) fast rotation of Wolf-Rayet stars and 2) low mass central black hole of the Milky Way. Keywords: mass-luminosity relation, stellar rotation, Wolf-Rayet stars, stellar angular momentum, Sagittarius A* mass, Sagittarius A* luminosity. In previous work (Alksnis, 2017) we have shown, that in slow rotating stars stellar luminosity is proportional to spin angular momentum of the star. This allows us to see, that there in fact are no stars outside of “main sequence” within stellar classes G, K and M. METHOD We have analyzed possible connection between stellar luminosity and stellar angular momentum in samples of most known F, A, B, O and WR class stars (tables 1-5). Stellar equatorial rotation speed (vsini) was used as main parameter of stellar rotation when possible. Several diverse data for one star were averaged. Zero stellar rotation speed was considered as an error and corresponding star has been not included in sample. RESULTS 2 F class star Relative Relative Luminosity, Relative M*R *eq mass, M radius, L rotation, L R eq HATP-6 1.29 1.46 3.55 2.950 2.28 α UMi B 1.39 1.38 3.90 38.573 26.18 Alpha Fornacis 1.33 -
Florida State University Libraries
Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School Constraining the Evolution of Massive StarsMojgan Aghakhanloo Follow this and additional works at the DigiNole: FSU's Digital Repository. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF ARTS AND SCIENCES CONSTRAINING THE EVOLUTION OF MASSIVE STARS By MOJGAN AGHAKHANLOO A Dissertation submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2020 Copyright © 2020 Mojgan Aghakhanloo. All Rights Reserved. Mojgan Aghakhanloo defended this dissertation on April 6, 2020. The members of the supervisory committee were: Jeremiah Murphy Professor Directing Dissertation Munir Humayun University Representative Kevin Huffenberger Committee Member Eric Hsiao Committee Member Harrison Prosper Committee Member The Graduate School has verified and approved the above-named committee members, and certifies that the dissertation has been approved in accordance with university requirements. ii I dedicate this thesis to my parents for their love and encouragement. I would not have made it this far without you. iii ACKNOWLEDGMENTS I would like to thank my advisor, Professor Jeremiah Murphy. I could not go through this journey without your endless support and guidance. I am very grateful for your scientific advice and knowledge and many insightful discussions that we had during these past six years. Thank you for making such a positive impact on my life. I would like to thank my PhD committee members, Professors Eric Hsiao, Kevin Huf- fenberger, Munir Humayun and Harrison Prosper. I will always cherish your guidance, encouragement and support. I would also like to thank all of my collaborators. -
1970Aj 75. . 602H the Astronomical Journal
602H . 75. THE ASTRONOMICAL JOURNAL VOLUME 75, NUMBER 5 JUNE 19 70 The Space Distribution and Kinematics of Supergiants 1970AJ Roberta M. Humphreys *f University of Michigan, Ann Arbor, Michigan (Received 15 January 1970; revised 1 April 1970) The distribution and kinematics of the supergiants of all spectral types are investigated with special emphasis on the correlation of these young stars and the interstellar gas. The stars used for this study are included as a catalogue of supergiants. Sixty percent of these supergiants occur in stellar groups. Least- squares solutions for the Galactic rotation constants yield 14 km sec-1 kpc-1 for Oort’s constant and a meaningful result for the second-order coefficient of —0.6 km sec-1 kpc-2. A detailed comparison of the stellar and gas velocities in the same regions shows good agreement, and these luminous stars occur in relatively dense gas. The velocity residuals for the stars also indicate noncircular group motions. In the Carina-Centaurus region, systematic motions of 10 km/sec were found between the two sides of the arm in agreement with Lin’s density-wave theory. The velocity residuals in the Perseus arm may also be due in part to these shearing motions. I. INTRODUCTION II. THE CATALOGUE OF SUPERGIANTS SINCE the pioneering work of Morgan et al. (1952) The observational data required for this study were on the distances of Galactic H 11 regions, many largely obtained from the literature. Use of a card file investigators have studied the space distribution of compiled by Dr. W. P. Bidelman was very helpful in various Population I objects, the optical tracers of this regard. -
A Revised Calibration of the Mv-W (OI 7774) Relationship Using Hipparcos
Revista Mexicana de Astronom´ıa y Astrof´ısica, XX, ??–12 (2002) A REVISED CALIBRATION OF THE MV − W (OI 7774) RELATIONSHIP USING HIPPARCOS DATA: ITS APPLICATION TO CEPHEIDS AND EVOLVED STARS1 A. Arellano Ferro2, Sunetra Giridhar3 and E. Rojo Arellano2 Received July 2002; accepted —— RESUMEN Se ha calculado una nueva calibraci´on de la correlaci´on MV − W (OI 7774) usando mejores estimaciones de enrojecimientos y distancias de 27 estrellas ca- libradoras de tipos A-G, basadas en los paralajes y movimientos propios de los cat´alogos Hiparcos y Tycho. La nueva calibraci´on predice magnitudes absolutas con precisiones de ± 0.38 mag. para una muestra que cubre el rango de −9.5 a +0.35 mag. El t´ermino de color, usado en calibraciones anteriores, no fue encontrado significativo y fue eliminado. Las variaciones del triplete OI7774 a lo largo del ciclo de pulsaci´on en la cefeida cl´asica SS Sct fueron estudiadas. Calculamos una correcci´on dependiente de la fase, a la intensidad del triplete de OI obtenida en fase al azar en Cefeidas, para determinar su magnitud absoluta media a traves de la relaci´on MV − W (OI 7774). Despu´es de aplicar esta correcci´on a una muestra de 31 Cefeidas, pudimos incrementar la lista de calibradoras a 58. La desviaci´on estandar de la calibraci´on usando la muestra combinada es comparable a la obtenida a partir de las 27 calibradoras primarias, lo que indica que el m´etodo permite obtener luminosidades medias de Cefeidas a partir de observaciones de OI7774 obtenidas al azar. -
European Southern Observatory
+ +lES+ OBSERVATORY (()) EUROPEAN SOUTHERN + COVER COUVfRTURf UMSCHLAG This cover highlights two IIhljor events Cette couverture met en evidence deux Dieser Umschl<lg hebt zwei 'wichl ofthe ye<lr, Clflmin<ltion ofsever<ll ye<lrs' evenements m<ljeurs de l',mnee - points Ereignisse des j,z/nes herv0/' - Hö of prep<lr<ltory development work. The Clflmirhlrzts de plusieurs <lrmees de tr<l punkte j<llnel,mger 'lHn'bereitender f contr<lct for the Unit Telescopes' M<lin V"'tX de developpements pnip,maoires. wicklungs<lrbeiten. Der Vertr,lg iiber Structure W,IS signed on September 24 Le contr,ll rel<ltzj"'ll<l structure principde Struktltr der vier finzelteleskope (see ,l!so the introdltction on p<lge 11). in des telescopes individuels du VLT <I ete VLT wurde <Im 24. September Imt October it W<lS decided to <ldopt ,m en signe le 24 septembre (voir l'intraduc zeichnet (siehe <!uch die finleitung I, c!osure type for the VLT which IIhlxi tion et LI photo 'Il<l p<lge 11). En octobre, d,ls Foto 'I/tf Seite 11). im Oktober m<llly protects the telescope <lrul its sensi l<l deeision fut prise d'<ldopter Itri type de die Entscheidung ji'ir einen Gelltiude tive prillhlry mirror while en<lbling ex bitiment qui, d'une p<lrt, ojji'e une pro ji'ir d,IS VLT, der einerseits einen md cellent therrn<ll <lnd <lir flow control to tection m<lximde du telescope et de son mden Schutz der Teleskope und ih elimin,lle deterior<ltion of seeing by this mirair princip,1! delic<lt et (jui, d'<lutre empfirul/ichen H'I/Iptspiegel ge·ühi.