Shedding Light on the Isolation of Luminous Blue Variables
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SCI/TSPM-PDR/001 Issue: 1.B Date: 20/10/2017 Pages
TSPM Science Document Code: SCI/TSPM-PDR/001 Issue: 1.B Date: 20/10/2017 Pages: 86 Code: SCI/TSPM-PDR/001 TSPM Science Document Issue: 1.B Date: 20/10/2017 Page: 2 of 86 Fernando Fabián Rosales Ortega (Project Scientist) Authors: Jesús González William Lee Revised by: Approved by: Contributors Galactic and stellar astronomy Extragalactic astronomy & Cosmology Carmen Ayala Heinz Andernach Emmanuele Bertone César A. Caretta Mónica W. Blanco Cárdenas Alberto Carramiñana Miguel Chávez Dagostino Marcel Chow-Martínez Luis J. Corral Deborah Dultzin Kessler Arturo Gómez-Ruíz Héctor Javier Ibarra Medel Martin A. Guerrero Simon N. Kemp Silvana G. Navarro Jiménez Omar López Cruz Manuel Nuñez Divakara Mayya Lorenzo Olguín Daniel Rosa Gonzalez Gerardo Ramos Larios Juan Pablo Torres Papaqui Mauricio Reyes Ruíz Olga Vega Michael Richer Carlos Román Zúñiga Future instrumentation Laurence Sabin Edgar Castillo Domínguez Miguel Ángel Trinidad Perla Carolina García Flores Roberto Vázquez Meza Sebastián F. Sánchez Sánchez Juan Luis Verbena Contreras Laurence Sabin Code: SCI/TSPM-PDR/001 TSPM Science Document Issue: 1.B Date: 20/10/2017 Page: 3 of 86 Distribution List Name Affiliation TSPM team All partners Document Change Record Issue Date Section Page Change description 1.A 17/09/2016 All All First issue Document updated from previous version. New science cases and instrumentation proposals included. 1.B 20/10/2017 Comments from the previous PDR panel considered. Comments and contributions from the TSPM Core Science Group included. Applicable and Reference Documents Nº Document Name Code R.1 TSPM: List of acronyms and abbreviations TEC/TSPM/001 Code: SCI/TSPM-PDR/001 TSPM Science Document Issue: 1.B Date: 20/10/2017 Page: 4 of 86 INDEX 1. -
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. -
14476 (Stsci Edit Number: 4, Created: Wednesday, September 7, 2016 4:28:02 PM EST) - Overview
Proposal 14476 (STScI Edit Number: 4, Created: Wednesday, September 7, 2016 4:28:02 PM EST) - Overview 14476 - A collision reversal in HD 5980 Cycle: 24, Proposal Category: GO (Availability Mode: SUPPORTED) INVESTIGATORS Name Institution E-Mail Dr. Yael Naze (PI) (ESA Member) (Contact) Universite de Liege [email protected] Dr. D. John Hillier (CoI) University of Pittsburgh [email protected] Dr. Gloria Koenigsberger (CoI) (Contact) Universidad Nacional Autonoma de Mexico (UNAM) [email protected] Dr. Julian M. Pittard (CoI) (ESA Member) University of Leeds [email protected] Dr. Michael F. Corcoran (CoI) Universities Space Research Association [email protected] Dr. Gregor Rauw (CoI) (ESA Member) Universite de Liege [email protected] VISITS Visit Targets used in Visit Configurations used in Visit Orbits Used Last Orbit Planner Run OP Current with Visit? 01 (1) HD-5980 STIS/CCD 2 07-Sep-2016 17:28:00.0 yes CCDFLAT STIS/FUV-MAMA 2 Total Orbits Used ABSTRACT HD 5980 provides a unique laboratory for studying the properties of wind-wind collisions. It contains one of only two binary systems having a WR- star in orbit with a LBV. The latter star has been observed to undergo major changes in its wind structure over the past 35 years, implying changes in the geometry and emitting conditions of the wind-wind collision region. Ten years ago, when the LBV wind was very strong, XMM observations revealed X-ray emission consistent with the shock cone wrapping around the WR component. Since then, the wind strength has significantly declined, implying that the collision shock cone may be inverting its orientation. -
Fundamental Parameters of Wolf-Rayet Stars VI
Astron. Astrophys. 320, 500–524 (1997) ASTRONOMY AND ASTROPHYSICS Fundamental parameters of Wolf-Rayet stars VI. Large Magellanic Cloud WNL stars? P.A.Crowther and L.J. Smith Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK Received 5 February 1996 / Accepted 26 June 1996 Abstract. We present a detailed, quantitative study of late WN Key words: stars: Wolf-Rayet;mass-loss; evolution; fundamen- (WNL) stars in the LMC, based on new optical spectroscopy tal parameters – galaxies: Magellanic Clouds (AAT, MSO) and the Hillier (1990) atmospheric model. In a pre- vious paper (Crowther et al. 1995a), we showed that 4 out of the 10 known LMC Ofpe/WN9 stars should be re-classified WN9– 10. We now present observations of the remaining stars (except the LBV R127), and show that they are also WNL (WN9–11) 1. Introduction stars, with the exception of R99. Our total sample consists of 17 stars, and represents all but one of the single LMC WN6– Quantitative studies of hot luminous stars in galaxies are im- 11 population and allows a direct comparison with the stellar portant for a number of reasons. First, and probably foremost, parameters and chemical abundances of Galactic WNL stars is the information they provide on the effect of the environment (Crowther et al. 1995b; Hamann et al. 1995a). Previously un- on such fundamental properties as the mass-loss rate and stellar published ultraviolet (HST-FOS, IUE-HIRES) spectroscopy are evolution. In the standard picture (e.g. Maeder & Meynet 1987) presented for a subset of our programme stars. -
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A&A 597, A92 (2017) Astronomy DOI: 10.1051/0004-6361/201628705 & c ESO 2017 Astrophysics Core-collapse supernova progenitor constraints using the spatial distributions of massive stars in local galaxies T. Kangas1, L. Portinari1, S. Mattila1,2,3, M. Fraser3, E. Kankare4, R. G. Izzard3, P. James5, C. González-Fernández3, J. R. Maund6,?, and A. Thompson4 1 Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland e-mail: [email protected] 2 Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland 3 Institute of Astronomy (IoA), University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK 4 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN, UK 5 Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool, L3 5RF, UK 6 The Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, UK Received 12 April 2016 / Accepted 20 August 2016 ABSTRACT We studied the spatial correlations between the Hα emission and different types of massive stars in two local galaxies, the Large Magellanic Cloud (LMC) and Messier 33. We compared these to correlations derived for core-collapse supernovae (CCSNe) in the literature to connect CCSNe of different types with the initial masses of their progenitors and to test the validity of progenitor mass estimates which use the pixel statistics method. We obtained samples of evolved massive stars in both galaxies from catalogues with good spatial coverage and/or completeness, and combined them with coordinates of main-sequence stars in the LMC from the SIMBAD database. -
The Stellar Parameters of the SMC WR Binary HD 5980
Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies Proceedings [AU Symposium No. 193, @1999 [AU K.A. van der Hucht, G. Koenigsberger & P.R.J. Eenens, eds. The stellar parameters of the SMC WR binary HD 5980 Jorg Schweickhardt' and Werner Schmutz/ 1Landessternwarte Koniqstuhl, D-69117 Heidelberg, Germany 2Institut fur Astronomie, ETH-Zentrum, CH-8092 Zurich, Switzerland Abstract. We present the temporal variation of the stellar parameters of the erupting star in HD 5980. We derive the effective temperature and radius from the observed changes of the visual magnitude. Our analysis is based on the assumption that the luminosity of the erupting star remained constant and that the brightness of the second star did not vary. 1. The determination of the stellar parameters T* and R* A simple method to derive the changes of the parameters T* and R* of a star is to analyze the variations of the visual magnitude My. Using Stefan-Boltzmann's law and the dependence of the observed flux, fA' on distance one gets oo 4 _ F Jo fAdA aT*- 1[' A fA . (1) Knowing the luminosity L ex Jooo fAdA and the visual magnitude My ex log fA' A == 5555 A, only the theoretical knowledge of the astrophysical flux FA emitted in the V band is needed to derive the temperature and the radius with equation (1). As a simple approximation we use here the Planck function BA(T*) for FA' If we want to apply this method to the binary system HD 5980, we need additional assumptions: (a) the LBV-like outburst in 1994 is the result of the eruption of only one star (star A, classified as an 071 star before eruption); (b) the luminosity of the erupting star remains constant with time; and (c) there is no variability of the companion (star B, WN 4). -
COMMISSIONS 27 and 42 of the I.A.U. INFORMATION BULLETIN on VARIABLE STARS Nos. 4101{4200 1994 October { 1995 May EDITORS: L. SZ
COMMISSIONS AND OF THE IAU INFORMATION BULLETIN ON VARIABLE STARS Nos Octob er May EDITORS L SZABADOS and K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI KONKOLY OBSERVATORY H BUDAPEST PO Box HUNGARY IBVSogyallakonkolyhu URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN 2 CONTENTS 1994 No page E F GUINAN J J MARSHALL F P MALONEY A New Apsidal Motion Determination For DI Herculis ::::::::::::::::::::::::::::::::::::: D TERRELL D H KAISER D B WILLIAMS A Photometric Campaign on OW Geminorum :::::::::::::::::::::::::::::::::::::::::::: B GUROL Photo electric Photometry of OO Aql :::::::::::::::::::::::: LIU QUINGYAO GU SHENGHONG YANG YULAN WANG BI New Photo electric Light Curves of BL Eridani :::::::::::::::::::::::::::::::::: S Yu MELNIKOV V S SHEVCHENKO K N GRANKIN Eclipsing Binary V CygS Former InsaType Variable :::::::::::::::::::: J A BELMONTE E MICHEL M ALVAREZ S Y JIANG Is Praesep e KW Actually a Delta Scuti Star ::::::::::::::::::::::::::::: V L TOTH Ch M WALMSLEY Water Masers in L :::::::::::::: R L HAWKINS K F DOWNEY Times of Minimum Light for Four Eclipsing of Four Binary Systems :::::::::::::::::::::::::::::::::::::::::: B GUROL S SELAN Photo electric Photometry of the ShortPeriod Eclipsing Binary HW Virginis :::::::::::::::::::::::::::::::::::::::::::::: M P SCHEIBLE E F GUINAN The Sp otted Young Sun HD EK Dra ::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::: M BOS Photo electric Observations of AB Doradus ::::::::::::::::::::: YULIAN GUO A New VR Cyclic Change of H in Tau :::::::::::::: -
Wolf-Rayet Spin at Low Metallicity and Its Implication for Black Hole
Astronomy & Astrophysics manuscript no. vink-wr c ESO 2021 July 27, 2021 Wolf-Rayet spin at low metallicity and its implication for Black Hole formation channels Jorick S. Vink1, Tim J. Harries2 1 Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, Northern Ireland, UK 2 Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK Preprint online version: July 27, 2021 ABSTRACT Context. The spin of Wolf-Rayet (WR) stars at low metallicity (Z) is most relevant for our understanding of gravitational wave sources such as GW 150914, as well as the incidence of long-duration gamma-ray bursts (GRBs). Two scenarios have been suggested for both phenomena: one of them involves rapid rotation and quasi-chemical homogeneous evolution (CHE), the other invokes classical evolution through mass loss in single and binary systems. Aims. The stellar spin of Wolf-Rayet stars might enable us to test these two scenarios. In order to obtain empirical constraints on black hole progenitor spin we infer wind asymmetries in all 12 known WR stars in the Small Magellanic Cloud (SMC) at Z = 1/5Z⊙, as well as within a significantly enlarged sample of single and binary WR stars in the Large Magellanic Cloud (LMC at Z = 1/2Z⊙), tripling the sample of Vink (2007). This brings the total LMC sample to 39, making it appropriate for comparison to the Galactic sample. Methods. We measure WR wind asymmetries with VLT-FORS linear spectropolarimetry, a tool uniquely poised to perform such tasks in extra- galactic environments. Results. We report the detection of new line effects in the LMC WN star BAT99-43 and the WC star BAT99-70, as well as the famous WR/LBV HD 5980 in the SMC, which might be evolving chemically homogeneously. -
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 -
Binocular Certificate Handbook
Irish Federation of Astronomical Societies Binocular Certificate Handbook How to see 110 extraordinary celestial sights with an ordinary pair of binoculars © John Flannery, South Dublin Astronomical Society, August 2004 No ordinary binoculars! This photograph by the author is of the delightfully whimsical frontage of the Chiat/Day advertising agency building on Main Street, Venice, California. Binocular Certificate Handbook page 1 IFAS — www.irishastronomy.org Introduction HETHER NEW to the hobby or advanced am- Wateur astronomer you probably already own Binocular Certificate Handbook a pair of a binoculars, the ideal instrument to casu- ally explore the wonders of the Universe at any time. Name _____________________________ Address _____________________________ The handbook you hold in your hands is an intro- duction to the realm far beyond the Solar System — _____________________________ what amateur astronomers call the “deep sky”. This is the abode of galaxies, nebulae, and stars in many _____________________________ guises. It is here that we set sail from Earth and are Telephone _____________________________ transported across many light years of space to the wonderful and the exotic; dense glowing clouds of E-mail _____________________________ gas where new suns are being born, star-studded sec- tions of the Milky Way, and the ghostly light of far- Observing beginner/intermediate/advanced flung galaxies — all are within the grasp of an ordi- experience (please circle one of the above) nary pair of binoculars. Equipment __________________________________ True, the fixed magnification of (most) binocu- IFAS club __________________________________ lars will not allow you get the detail provided by telescopes but their wide field of view is perfect for NOTES: Details will be treated in strictest confidence. -
UV Spectroscopy of Massive Stars
galaxies Review UV Spectroscopy of Massive Stars D. John Hillier Department of Physics and Astronomy & Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260, USA; [email protected] Received: 11 July 2020; Accepted: 6 August 2020; Published: 12 August 2020 Abstract: We present a review of UV observations of massive stars and their analysis. We discuss O stars, luminous blue variables, and Wolf–Rayet stars. Because of their effective temperature, the UV (912 − 3200 Å) provides invaluable diagnostics not available at other wavebands. Enormous progress has been made in interpreting and analysing UV data, but much work remains. To facilitate the review, we provide a brief discussion on the structure of stellar winds, and on the different techniques used to model and interpret UV spectra. We discuss several important results that have arisen from UV studies including weak-wind stars and the importance of clumping and porosity. We also discuss errors in determining wind terminal velocities and mass-loss rates. Keywords: massive stars; O stars; Wolf–Rayet stars; UV; mass loss; stellar winds 1. Introduction According to Wien’s Law, the peak of a star’s energy distribution occurs in the UV for a star whose temperature exceeds 10,000 K. In practice, the temperature needs to exceed 10,000 K because of the presence of the Balmer jump. Temperatures greater than 10,000 K correspond to main-sequence stars of mass greater than ∼ 2 M and spectral types B9 and earlier. Early UV observations were made by rocket-flown instruments (e.g., [1,2]). -
Wolf-Rayet Spin at Low Metallicity and Its Implication for Black Hole Formation Channels Jorick S
A&A 603, A120 (2017) Astronomy DOI: 10.1051/0004-6361/201730503 & c ESO 2017 Astrophysics Wolf-Rayet spin at low metallicity and its implication for black hole formation channels Jorick S. Vink1 and Tim J. Harries2 1 Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, Northern Ireland, UK e-mail: [email protected] 2 Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK Received 26 January 2017 / Accepted 28 March 2017 ABSTRACT Context. The spin of Wolf-Rayet (WR) stars at low metallicity (Z) is most relevant for our understanding of gravitational wave sources, such as GW 150914, and of the incidence of long-duration gamma-ray bursts (GRBs). Two scenarios have been suggested for both phenomena: one of them involves rapid rotation and quasi-chemical homogeneous evolution (CHE) and the other invokes classical evolution through mass loss in single and binary systems. Aims. The stellar spin of WR stars might enable us to test these two scenarios. In order to obtain empirical constraints on black hole progenitor spin we infer wind asymmetries in all 12 known WR stars in the Small Magellanic Cloud (SMC) at Z = 1=5 Z and within a significantly enlarged sample of single and binary WR stars in the Large Magellanic Cloud (LMC at Z = 1=2 Z ), thereby tripling the sample of Vink from 2007. This brings the total LMC sample to 39, making it appropriate for comparison to the Galactic sample. Methods. We measured WR wind asymmetries with VLT-FORS linear spectropolarimetry, a tool that is uniquely poised to perform such tasks in extragalactic environments.