Evidence for Binary Interaction?!
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Eversberg2011b.Pdf
AMATEUR ASTRONOMERS have always admired pro fessionals for their awesome telescopes and equipment, their access to the world's best observing sites, and also for their detailed, methodical planning to do the most productive possible projects. Compared to what most of us do, professional astronomy is in a different league. This is a story ofhow some of us went there and played on the same field. Backyard amateurs have always contributed to astron omy research, but digital imaging and data collection have broadened their range enormously. One new field for amateurs is taking spectra of bright, massive stars to monitor variable emission lines and other stellar activity. Skilled amateurs today can build, or buy off-the-shelf, small, high quality spectrographs that meet professional HIDDEN IN PLAIN SICHT In one ofthe summer Milky requirements for such projects. Way's most familiar rich fields for binoculars, the colliding-wind Professional spectrographs, meanwhile, binary star WR 140 (also known as HO 193793 and V1687 Cygni) are usually found on heavily oversubscribed is almost lost among other 7th-magnitude specks. telescopes that emphasize "fashionable" BY THOMAS research and projects that can be accom plished with the fewest possible telescope EVERSBERG hours granted by a time-allocation commit- tee. H's hard to get large amounts of time for an extended observing campaign. So we created an unusual pro-am collaboration in order to bypass this problem. Theldea In 2006 I had a discussion with my mentor and friend Anthony Moffat at the University ofMontreal, who for many years has been a specialist in massive hot stars. -
On the Apparent Absence of Wolf–Rayet+Neutron Star Systems: the Urc Ious Case of WR124 Jesus A
East Tennessee State University Digital Commons @ East Tennessee State University ETSU Faculty Works Faculty Works 12-10-2018 On the Apparent Absence of Wolf–Rayet+Neutron Star Systems: The urC ious Case of WR124 Jesus A. Toala UNAM Campus Morelia Lidi Oskinova University of Potsdam W.R. Hamann University of Potsdam Richard Ignace East Tennessee State University, [email protected] A.A. C. Sander University of Potsdam See next page for additional authors Follow this and additional works at: https://dc.etsu.edu/etsu-works Citation Information Toala, Jesus A.; Oskinova, Lidi; Hamann, W.R.; Ignace, Richard; Sander, A.A. C.; Todt, H.; Chu, Y.H.; Guerrero, M. A.; Hainich, R.; Hainich, R.; and Terrejon, J. M.. 2018. On the Apparent Absence of Wolf–Rayet+Neutron Star Systems: The urC ious Case of WR124. Astrophysical Journal Letters. Vol.869 https://doi.org/10.3847/2041-8213/aaf39d ISSN: 2041-8205 This Article is brought to you for free and open access by the Faculty Works at Digital Commons @ East Tennessee State University. It has been accepted for inclusion in ETSU Faculty Works by an authorized administrator of Digital Commons @ East Tennessee State University. For more information, please contact [email protected]. On the Apparent Absence of Wolf–Rayet+Neutron Star Systems: The Curious Case of WR124 Copyright Statement © 2018. The American Astronomical Society. Reproduced by permission of the AAS. Creator(s) Jesus A. Toala, Lidi Oskinova, W.R. Hamann, Richard Ignace, A.A. C. Sander, H. Todt, Y.H. Chu, M. A. Guerrero, R. Hainich, R. Hainich, and J. M. -
POSTERS SESSION I: Atmospheres of Massive Stars
Abstracts of Posters 25 POSTERS (Grouped by sessions in alphabetical order by first author) SESSION I: Atmospheres of Massive Stars I-1. Pulsational Seeding of Structure in a Line-Driven Stellar Wind Nurdan Anilmis & Stan Owocki, University of Delaware Massive stars often exhibit signatures of radial or non-radial pulsation, and in principal these can play a key role in seeding structure in their radiatively driven stellar wind. We have been carrying out time-dependent hydrodynamical simulations of such winds with time-variable surface brightness and lower boundary condi- tions that are intended to mimic the forms expected from stellar pulsation. We present sample results for a strong radial pulsation, using also an SEI (Sobolev with Exact Integration) line-transfer code to derive characteristic line-profile signatures of the resulting wind structure. Future work will compare these with observed signatures in a variety of specific stars known to be radial and non-radial pulsators. I-2. Wind and Photospheric Variability in Late-B Supergiants Matt Austin, University College London (UCL); Nevyana Markova, National Astronomical Observatory, Bulgaria; Raman Prinja, UCL There is currently a growing realisation that the time-variable properties of massive stars can have a funda- mental influence in the determination of key parameters. Specifically, the fact that the winds may be highly clumped and structured can lead to significant downward revision in the mass-loss rates of OB stars. While wind clumping is generally well studied in O-type stars, it is by contrast poorly understood in B stars. In this study we present the analysis of optical data of the B8 Iae star HD 199478. -
PDF Version in Chronological Order (Updated May 17, 2013)
Complete Bibliography for Ritter Observatory May 17, 2013 The following papers are based in whole or in part on observations made at Ritter Observatory. External collaborators are listed in parentheses unless the research was done while they were University of Toledo students. Refereed or invited: 1. A. H. Delsemme and J. L. Moreau 1973, Astrophys. Lett., 14, 181–185, “Brightness Profiles in the Neutral Coma of Comet Bennett (1970 II)” 2. B. W. Bopp and F. Fekel Jr. 1976, A. J., 81, 771–773, “HR 1099: A New Bright RS CVn Variable” 3. A. H. Delsemme and M. R. Combi 1976, Ap. J. (Letters), 209, L149–L151, “The Production Rate and Possible Origin of O(1D) in Comet Bennett 1970 II” 4. A. H. Delsemme and M. R. Combi 1976, Ap. J. (Letters), 209, L153–L156, “Production + Rate and Origin of H2O in Comet Bennett 1970 II” 5. D. W. Willmarth 1976, Pub. A. S. P., 88, 86–87, “The Orbit of 71 Draconis” 6. W. F. Rush and R. W. Thompson 1977, Ap. J., 211, 184–188, “Rapid Variations of Emission-Line Profiles in Nova Cygni 1975” 7. S. E. Smith and B. W. Bopp 1980, Pub. A. S. P., 92, 225–232, “A Microcomputer-Based System for the Automated Reduction of Astronomical Spectra” 8. B. W. Bopp and P. V. Noah 1980, Pub. A. S. P., 92, 333–337, “Spectroscopic Observations of the Surface-Activity Binary II Pegasi (HD 224085)” 9. M. R. Combi and A. H. Delsemme 1980, Ap. J., 237, 641–645, “Neutral Cometary Atmospheres. II. -
PHAS 1102 Physics of the Universe 3 – Magnitudes and Distances
PHAS 1102 Physics of the Universe 3 – Magnitudes and distances Brightness of Stars • Luminosity – amount of energy emitted per second – not the same as how much we observe! • We observe a star’s apparent brightness – Depends on: • luminosity • distance – Brightness decreases as 1/r2 (as distance r increases) • other dimming effects – dust between us & star Defining magnitudes (1) Thus Pogson formalised the magnitude scale for brightness. This is the brightness that a star appears to have on the sky, thus it is referred to as apparent magnitude. Also – this is the brightness as it appears in our eyes. Our eyes have their own response to light, i.e. they act as a kind of filter, sensitive over a certain wavelength range. This filter is called the visual band and is centred on ~5500 Angstroms. Thus these are apparent visual magnitudes, mv Related to flux, i.e. energy received per unit area per unit time Defining magnitudes (2) For example, if star A has mv=1 and star B has mv=6, then 5 mV(B)-mV(A)=5 and their flux ratio fA/fB = 100 = 2.512 100 = 2.512mv(B)-mv(A) where !mV=1 corresponds to a flux ratio of 1001/5 = 2.512 1 flux(arbitrary units) 1 6 apparent visual magnitude, mv From flux to magnitude So if you know the magnitudes of two stars, you can calculate mv(B)-mv(A) the ratio of their fluxes using fA/fB = 2.512 Conversely, if you know their flux ratio, you can calculate the difference in magnitudes since: 2.512 = 1001/5 log (f /f ) = [m (B)-m (A)] log 2.512 10 A B V V 10 = 102/5 = 101/2.5 mV(B)-mV(A) = !mV = 2.5 log10(fA/fB) To calculate a star’s apparent visual magnitude itself, you need to know the flux for an object at mV=0, then: mS - 0 = mS = 2.5 log10(f0) - 2.5 log10(fS) => mS = - 2.5 log10(fS) + C where C is a constant (‘zero-point’), i.e. -
Revisiting the Impact of Dust Production from Carbon-Rich Wolf-Rayet Binaries
Draft version June 17, 2020 Typeset using LATEX twocolumn style in AASTeX62 Revisiting the Impact of Dust Production from Carbon-Rich Wolf-Rayet Binaries Ryan M. Lau,1 J.J. Eldridge,2 Matthew J. Hankins,3 Astrid Lamberts,4 Itsuki Sakon,5 and Peredur M. Williams6 1Institute of Space & Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan 2Department of Physics, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand 3Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 4Universit´eC^oted'Azur, Observatoire de la C^oted'Azur, CNRS, Laboratoire Lagrange, Laboratoire ARTEMIS, France 5Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 6Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (Accepted June 12, 2020) Submitted to ApJ ABSTRACT We present a dust spectral energy distribution (SED) and binary stellar population analysis revisiting the dust production rates (DPRs) in the winds of carbon-rich Wolf-Rayet (WC) binaries and their impact on galactic dust budgets. DustEM SED models of 19 Galactic WC \dustars" reveal DPRs of −10 −6 −1 M_ d ∼ 10 − 10 M yr and carbon dust condensation fractions, χC , between 0:002 − 40%. A large (0:1 − 1:0 µm) dust grain size composition is favored for efficient dustars where χC & 1%. Results for dustars with known orbital periods verify a power-law relation between χC , orbital period, WC mass-loss rate, and wind velocity consistent with predictions from theoretical models of dust formation in colliding-wind binaries. -
Amateur Astronomical Pro-Am Spectroscopy
AmateurAmateur AstronomicalAstronomical Olivier Thizy Pro-AmPro-Am [email protected] --- SpectroscopySpectroscopy May 25th, 2011 -- SAS ; big Bear, CA -- the “menu”... • Introduction • Educational • Pro/Am projects ● Be stars, delta Sco focus ● WR 140, «covento» group ● epsilon Aurigae campaign 25/05/11 (c)Introduction 2006 - Shelyak Instruments 3 Take some good Resolutions ! Resolution R = λ / ∆λ 20000 eShel 10000 Lhires III 1000 LISA 100 Star Analyser 25/05/11 (c) 2006 - Shelyak Instruments Spectral Domain Coverage4 Applications eShel High level education Bright stars line profile (Be stars, pulsations...) Abundances, classification Spectroscopic binaries & exoplanets Lhires III (self) education with low / medium / high resolution modes Stellar classification Bright stars line profile (Be stars, eps Aur, Wolf-Rayet, Slow Pulsating B stars, Herbig Ae/Be...) LISA Education: lamp, classification, nebulae, galaxie redshift... Faint variable stars: cataclysmics, novae, mira... Comets classification Asteroids classification ... Star Analyser Education: star temperature & classification Novae Faint variable stars Supernovae 25/05/11 (c) 2006 - Shelyak Instruments 5 Some steps back... 25/05/11 (c) 2006 - Shelyak Instruments 6 Oleron 2003 ➢The situation ➢Very few pro/am collaboration (e.g. Buil Be star atlas, Maurice Gavin, Dale Mais...), done with custom designed spectrographs. ➢Oleron 2003 ➢AUDE/CNRS pro/am official school ➢Preceedings book to be published soon ➢Kick off for Lhires III design ➢Kick off Spectro-L list ➢Kick off ARAS website front-end La Rochelle: 2006 ➢Be Stars Spectra (BeSS) database kick off ➢Structuring spectra collection & archiving ➢Defining a spectra file format (FITS based) ➢Workshop on Lhires III (AUDE first kits just received !) La Rochelle: 2009 ➢10000 amateur spectra in BeSS.. -
Spatial Distribution of Galactic Wolf–Rayet Stars and Implications for the Global Population
MNRAS 447, 2322–2347 (2015) doi:10.1093/mnras/stu2525 Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population C. K. Rosslowe‹ andP.A.Crowther Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, UK Accepted 2014 November 26. Received 2014 November 26; in original form 2014 September 5 ABSTRACT We construct revised near-infrared absolute magnitude calibrations for 126 Galactic Wolf– Rayet (WR) stars at known distances, based in part upon recent large-scale spectroscopic surveys. Application to 246 WR stars located in the field permits us to map their Galactic distribution. As anticipated, WR stars generally lie in the thin disc (∼40 pc half-width at half- maximum) between Galactocentric radii 3.5–10 kpc, in accordance with other star formation tracers. We highlight 12 WR stars located at vertical distances of ≥300 pc from the mid-plane. Analysis of the radial variation in WR subtypes exposes a ubiquitously higher NWC/NWN ratio than predicted by stellar evolutionary models accounting for stellar rotation. Models for non- rotating stars or accounting for close binary evolution are more consistent with observations. We consolidate information acquired about the known WR content of the Milky Way to build a simple model of the complete population. We derive observable quantities over a range of wavelengths, allowing us to estimate a total number of 1900 ± 250 Galactic WR stars, implying an average duration of ∼ 0.4 Myr for the WR phase at the current Milky Way star formation rate. Of relevance to future spectroscopic surveys, we use this model WR population to predict follow-up spectroscopy to KS 17.5 mag will be necessary to identify 95 per cent of Galactic WR stars. -
Herschel Observations of the Nebula M1-67 Around the Wolf-Rayet Star WR 124 ,
A&A 588, A92 (2016) Astronomy DOI: 10.1051/0004-6361/201527667 & c ESO 2016 Astrophysics Herschel observations of the nebula M1-67 around the Wolf-Rayet star WR 124, C. Vamvatira-Nakou1, D. Hutsemékers1,,P.Royer2,C.Waelkens2,M.A.T.Groenewegen3, and M. J. Barlow4 1 Institut d’Astrophysique et de Géophysique, Université de Liège, Quartier Agora, Allée du 6 août, 19C − Bât. B5c, 4000 Liège (Sart-Tilman), Belgium e-mail: [email protected] 2 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, Bus 2401, 3001 Leuven, Belgium 3 Koninklijke Sterrenwacht van België, Ringlaan 3, 1180 Brussels, Belgium 4 Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK Received 30 October 2015 / Accepted 29 January 2016 ABSTRACT Infrared Herschel imaging and spectroscopic observations of the nebula M1-67 around the Wolf-Rayet star WR 124 have been obtained along with optical imaging observations. The infrared images reveal a clumpy dusty nebula that extends up to 1 pc. The comparison with the optical images shows that the ionized gas nebula coincides with the dust nebula, the dust and the gas being mixed together. A photodissociation region is revealed from the infrared spectroscopic analysis. The analysis of the infrared spectrum of the nebula, where forbidden emission lines of ionized elements were detected, showed that the nebula consists of mildly processed material with the calculated abundance number ratios being N/O = 1.0 ± 0.5 and C/O = 0.46 ± 0.27. Based on a radiative transfer model, the dust mass of the nebula was estimated to be 0.22 M with a population of large grains being necessary to reproduce the observations. -
Downloaded From
MNRAS Advance Access published May 30, 2016 The dusty pinwheel WR 98a 1 Pinwheels in the sky, with dust: 3D modeling of the Wolf-Rayet 98a environment Tom Hendrix1, Rony Keppens1?, Allard Jan van Marle1, Peter Camps2, Maarten Baes2, and Zakaria Meliani3 1Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium 2Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent, Belgium 3Observatoire de Paris, 5 place Jules Janssen 92195 Meudon, France Downloaded from Accepted XXX. Received YYY; in original form ZZZ ABSTRACT The Wolf-Rayet 98a (WR 98a) system is a prime target for interferometric surveys, since its identi- http://mnras.oxfordjournals.org/ fication as a \rotating pinwheel nebulae", where infrared images display a spiral dust lane revolving with a 1.4 year periodicity. WR 98a hosts a WC9+OB star, and the presence of dust is puzzling given the extreme luminosities of Wolf-Rayet stars. We present 3D hydrodynamic models for WR 98a, where dust creation and redistribution are self-consistently incorporated. Our grid-adaptive simulations resolve details in the wind collision region at scales below one percent of the orbital separation (∼ 4 AU), while simulating up to 1300 AU. We cover several orbital periods under condi- tions where the gas component alone behaves adiabatic, or is subject to effective radiative cooling. In the adiabatic case, mixing between stellar winds is effective in a well-defined spiral pattern, where optimal conditions for dust creation are met. When radiative cooling is incorporated, the interac- at KU Leuven University Library on May 31, 2016 tion gets dominated by thermal instabilities along the wind collision region, and dust concentrates in clumps and filaments in a volume-filling fashion, so WR 98a must obey close to adiabatic evo- lutions to demonstrate the rotating pinwheel structure. -
Introduction to Astronomical Spectroscopy Trough the Eyes of an Alpy 600 Spectrograph in Cygnus Constellation
Introduction to astronomical spectroscopy trough the eyes of an Alpy 600 spectrograph in Cygnus constellation Olivier THIZY Webb Society annual meeting Cambridge, 20 june 2015 Photo: Jim Edlin, OHP AgendaAgenda ● How does a slit spectroscope works? ● Kirchhoff's law through Albireo exemple ● P Cygni: Doppler Fizeau effect ● Nova Del 2013: Spectro-photometry, pro/am ● Pulsating stars: quest for higher resolution ● Some other variable stars ● Conclusions InsideInside thethe AlpyAlpy 600600 spectroscopespectroscope objective collimator lens lens disperser (prism or grating) sensor source slit ImportanceImportance ofof thethe slitslit 3mm slit (hole) 300µm slit 25µm slit Cat'sCat's eyeeye nebulanebula // nono slitslit VsVs slitslit R=100, without slit R=17000, slit R=1000, 23µm slit © Torsten Hansen, Robin Leadbeater, O. Thizy MirrorMirror slitslit ● Centering ● (auto)Guiding © C. Buil, O. Thizy TheThe AlpyAlpy 600600 systemsystem onon aa scopescope a spectrum is an image that can be also displayed as a spectral profile Kirchhoff's law's through Albireo beta Cygni (Albireo) Photos: Jim Edlin (Cygne), Eric Coustal (Albireo) Albireo (1) (1) Overshape profile (2) Absorption lines (3) Emission line (3) (1) (2) Perfect exemple of Kirchhoff's laws... Photos: Eric Coustal (Albireo) & Wikipedia 1: overall profile --> Temp. 4000K Wikipedia: 4080K 13000K Wikipedia: 13200K Analyse: VisualSpec; photo Aliréo: Eric Coustal 2: stellar atmosphere Hydrogen lines Spectral classification hydrogène 68 Cyg O5V lam Cyg B5V 40 Cyg A3V the Cyg F4V zet Cyg G8II 61 Cyg K5V 19 Cyg M2IIIa H/K Na (D) atmosphère Oh, Be A Fine Girl/Guy... Kiss Me ! Absorption lines physics Exemple for the hydrogen atom Sources: http://culturesciencesphysique.ens-lyon.fr/ressource/Quantique.xml &: http://e.m.c.2.free.fr/niveaux-energie-hydrogene-emission-absorption.htm Temperature Vs line strength 40 Cyg A3V the Cyg F4V 19 Cyg M2IIIa ex: calcium 'Ca II' hydrogène toward cooler effective temperature Luminosity class Alp Cyg (A2I) 40 Cyg (A3V) Hertzspring-Russell diagram © J. -
Self-Evaluation Document of the Research Institute of Physics and Astronomy Faculty of Physics and Astronomy Utrecht University
SELF-EVALUATION DOCUMENT OF THE RESEARCH INSTITUTE OF PHYSICS AND ASTRONOMY FACULTY OF PHYSICS AND ASTRONOMY UTRECHT UNIVERSITY This is the self-evaluation document of the Research Institute of Physics and Astronomy prepared for its upcoming research assessment organized by the Governing Board of Utrecht University. It is prepared on the basis of the Evaluation Protocol [1] which is derived from the Standard Evaluation Protocol 2003-2009 for public research organizations in the Netherlands [2]. The purpose of the evaluation is to assess against international standard the quality, productivity, relevance and viability of the activities of the Research Institute and its thirteen research programs during the seven-year period that ended on 31 December 2002. Part A describes the Research Institute as a whole and Part B the separate research programs. Part B is prepared in close collaboration with the program leaders of the respective programs. Besides extensive descriptions of the mission and the organization of the Institute and its programs, detailed annual data are presented regarding the research staff, the productivity and the funding. This report has been approved by the Governing Board of Utrecht University. It will be submitted as an input document for the evaluation of the Research Institute of Physics and Astronomy to the Evaluation Committee. The Evaluation Committee consists of Prof. dr. Edouard Brézin, (ENS, Paris; Chair); Prof. dr. Marcel Arnould, (Université Libre de Bruxelles); Prof. dr. Paul M. Chaikin, (Princeton University); Prof. dr. Jos Eggermont, (University of Calgary); Prof. dr. Michael Ghil, (UCLA, ENS Paris); Prof. dr. Jürgen Mlynek, (Humboldt Universität zu Berlin). The site visit is set for 10-12 September 2003.