DOCSLIB.ORG

Study of Physical Characteristics and Superhump – Orbital Period Relationship of Su Ursae Majoris Type Stars

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Study of Physical Characteristics and Superhump – Orbital Period Relationship of Su Ursae Majoris Type Stars Study of physical characteristics and superhump – orbital period relationship of Su Ursae Majoris type stars By Pestheruwe Liyanaralalage Sujith Lakshan Cooray B.Sc(Special) 2018 Study of physical characteristics and superhump – orbital period relationship of Su Ursae Majoris type stars By Pestheruwe Liyanaralalage Sujith Lakshan Cooray Index No: AS2013336 Dissertation submitted in partial fulfillment of the requirement for the degree of Bachelor of Science in Physics University of Sri Jayewardenepura On 10-01-2018 DECLARATION The work described in this dissertation was carried out by me in collaboration with the Department of Physics, University of Sri Jayewardenepura, Sri Lanka under the guidance Dr. Shantha Gamage, senior lecturer, University of Sri Jayewardenepura, Sri Lanka and Mr. Indika Medagangoda, Research Scientist (Astronomy), Arthur C Clarke Institute for Modern Technologies, Sri Lanka and has not submitted elsewhere. 10th January 2018 ……………………………. Date of submission P.L.S.L.Cooray …………………………….. …………………………….. Dr. Shantha Gamage Mr. Indika Medagangoda, Supervisor /Department of Physics, Research Scientist (Astronomy), University of Sri Jayewardenepura Arthur C Clarke Institute for Modern Technologies, Sri Lanka …………………………... …………………………... Dr. W. D. A.T. Wijerathne, Prof. Sudantha Liyanage, Head/Department of Physics, Dean/Faculty of Applied Sciences, University of Sri Jayewardenepura. University of Sri Jayewardenepura. i Acknowledgements I would like to express my deepest gratitude to my internal supervisor Dr. Shantha Gamage, Faculty of Applied Sciences, University of Sri Jayawardenepura, Sri Lanka, for make the way for me to attend of Arthur C Clarke Institute for Modern Technologies, Katubadda and guidance me throughout the study. I hereby acknowledge, with deep sense of gratitude to my external supervisor Mr. Indika Madagangoda whose Research Scientist in astronomy of Arthur C Clarke Institute for Modern Technologies, Katubadda. Great thanks are also due to the Eng.Sanath Panawannage, Director of Arthur C Clarke Institute for Modern Technologies; Head of Space Application Division Mr. Saraj Gunasekara; Research Scientist Janaka Adassuriya & all staff members of Arthur C Clarke Institute for Modern Technologies for their invaluable support and sharing knowledge with me. I specially remind my parents who made me interest about field of Astronomy when I was a kid. Finally would like to thanks all my friends and my loved one giving their support and encouraging words to success this study. Sujith Lakshan Cooray January 2018 ii Abstract The photometric study of the main characteristics of the SU Ursae Majoris (SU UMa) stars is the main objective of this research. SU Ursae Majoris (SU UMa) stars belongs to the dwarf novae class of intrinsic cataclysmic variable (CV) stars. The relevant data obtained through Arthur C. Clarke Institute (ACCIMT) were analyzed from Image Reduction and Analysis Facility (IRAF), a professional astronomical data reduction and analysis software in Linux platform. During the period of the study raw image frames of four SU UMa stars such as SDSS0932, IY UMa, J0426 and J0711 were obtained. A set of time series raw images were analyzed by construction of light curves after reducing their dark, flat and bias noises. Since the obtained data samples were very faint, beyond 15 mag, a careful precise attention was made to reduce the noises of these frames. While Qphot and Phot packages in IRAF were mainly used for this data reduction and analysis the obtained results were compared with an IRAF script program (a program program that was written in iraf based programming method). Although it is found that there is a 0.5 magnification difference between IRAF Phot task and IRAF script the shapes of the features in their light curves were almost same. The main result of this research was obtained through the constructed light curve of the IY UMa system where it was observed normal bursts, one of the main characteristics of SU UMa systems, and an eclipse between normal star and the white dwarf the main components of a SU UMa system. The orbital period of the IY UMa was determined as 0.0743 days. The flux variation of the hotspot of the binary system was also clearly identified through the light curve iii Contents Declaration .................................................................................................................... i Acknowledgements ........................................................................................................ ii Abstract ........................................................................................................................ iii Contents ....................................................................................................................... iv List of Abbreviations ................................................................................................... vii List of Figures ............................................................................................................ viii Chapter 1 ......................................................................................................................... 1 GENERAL INTRODUCTION .................................................................................. 1 1.1 INTRODUCTION .......................................................................................... 1 1.2 VARIABLE STARS ...................................................................................... 3 1.2.1 CATACLYSMIC VARIABLE STARS ...................................................... 5 1.2.2 SU URSAE MAJORIS TYPE STARS ................................................... 7 1.3 SCOPE OF THE STUDY ............................................................................... 8 Chapter 2 ....................................................................................................................... 10 THEORETICAL BACKGROUND OF THE SU UMA STARS .......................... 10 2.1 INTRODUCTION ........................................................................................ 10 2.2 ORBITAL PERIOD ...................................................................................... 11 2.3 ROCHE LOBE GEOMETRY ...................................................................... 12 2.4 MASS TRANSFER ...................................................................................... 13 2.4.1 ROCHE LOBE OVERFLOW ............................................................... 14 iv 2.4.2 STREAM TRAJECTORY .................................................................... 15 2.4.3 BRIGHT SPOT ..................................................................................... 18 2.5 ACCRETION DICS ..................................................................................... 20 2.5.1 VISCOSITY .......................................................................................... 21 2.5.2 BOUNDARY LAYER .......................................................................... 22 2.5.3 TIDAL LIMITATION .......................................................................... 22 2.5.4 DISC PRECESSION ............................................................................. 22 Chapter 3 ....................................................................................................................... 24 METHODOLOGY .................................................................................................... 24 3.1 OBSERVING STARS .................................................................................. 24 3.1.1 SRI LANKAN LARGEST TELESCOPE IN ARTHUR C CLARKE INSTITUTE FOR MODERN TECHNOLOGIES (ACCIMT) .......................... 24 3.1.2 ONLINE OBSERVATION ................................................................... 25 3.1.3 KEPLER TELESCOPE DATA ............................................................. 26 3.2 IMAGE REDUCTION AND ANALYSIS FACILITY (IRAF) ................... 27 3.3 FIELD CORRECTIONS .............................................................................. 28 3.3.1 BIAS CORRECTION ........................................................................... 30 3.3.2 DARK CORRECTION ......................................................................... 30 3.3.3 FLAT CORRECTION .......................................................................... 30 3.4 PHOTOMETRY ........................................................................................... 31 3.5 IRAF SCRIPT ............................................................................................... 32 v Chapter 4 ....................................................................................................................... 42 RESULTS .................................................................................................................. 42 4.1 INTRODUCTION ........................................................................................ 42 4.2 IY UMa ......................................................................................................... 43 4.3 SDSS0932 ..................................................................................................... 46 4.4 J0426 ............................................................................................................. 47 4.5 J0711 ............................................................................................................. 49 Chapter 5 ......................................................................................................................
Load more

Recommended publications
  • Whole Earth Telescope Observations of AM Canum Venaticorum – Discoseismology at Last
    Astron. Astrophys. 332, 939–957 (1998) ASTRONOMY AND ASTROPHYSICS Whole Earth Telescope observations of AM Canum Venaticorum – discoseismology at last J.-E. Solheim1;14, J.L. Provencal2;15, P.A. Bradley2;16, G. Vauclair3, M.A. Barstow4, S.O. Kepler5, G. Fontaine6, A.D. Grauer7, D.E. Winget2, T.M.K. Marar8, E.M. Leibowitz9, P.-I. Emanuelsen1, M. Chevreton10, N. Dolez3, A. Kanaan5, P. Bergeron6, C.F. Claver2;17, J.C. Clemens2;18, S.J. Kleinman2, B.P. Hine12, S. Seetha8, B.N. Ashoka8, T. Mazeh9, A.E. Sansom4;19, R.W. Tweedy4, E.G. Meistasˇ 11;13, A. Bruvold1, and C.M. Massacand1 1 Nordlysobservatoriet, Institutt for Fysikk, Universitetet i Tromsø, N-9037 Tromsø, Norway 2 McDonald Observatory and Department of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA 3 Observatoire Midi–Pyrenees, 14 Avenue E. Belin, F-31400 Toulouse, France 4 Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK 5 Instituto de Fisica, Universidade Federal do Rio Grande do Sul, 91500-970 Porto Alegre - RS, Brazil 6 Department de Physique, Universite´ de Montreal,´ C.P. 6128, Succ A., Montreal,´ PQ H3C 3J7, Canada 7 Department of Physics and Astronomy, University of Arkansas, 2801 S. University Ave, Little Rock, AR 72204, USA 8 Technical Physics Division, ISRO Satelite Centre, Airport Rd, Bangalore, 560 017 India 9 University of Tel Aviv, Department of Physics and Astronomy, Ramat Aviv, Tel Aviv 69978, Israel 10 Observatoire de Paris-Meudon, F-92195 Meudon Principal Cedex, France 11 Institute of Material Research and Applied Sciences, Vilnius University, Ciurlionio 29, Vilnius 2009, Lithuania 12 NASA Ames Research Center, M.S.
    [Show full text]
  • 1000 Cataclysmic Variables from the Catalina Real-Time Transient Survey
    MNRAS 443, 3174–3207 (2014) doi:10.1093/mnras/stu1377 1000 cataclysmic variables from the Catalina Real-time Transient Survey E. Breedt,1‹ B. T. Gansicke,¨ 1 A. J. Drake,2 P. Rodr´ıguez-Gil,3,4 S. G. Parsons,5 T. R. Marsh,1 P. Szkody,6 M. R. Schreiber5 and S. G. Djorgovski2 1Department of Physics, University of Warwick, Coventry, CV4 7AL, UK 2California Institute of Technology, 1200 E. California Blvd, CA 91225, USA 3Instituto de Astrof´ısica de Canarias, V´ıa Lactea´ s/n, La Laguna, E-38205, Santa Cruz de Tenerife, Spain 4Departamento de Astrof´ısica, Universidad de La Laguna, La Laguna, E-38206, Santa Cruz de Tenerife, Spain 5Instituto de F´ısica y Astronom´ıa, Universidad de Valpara´ıso, Avenida Gran Bretana 1111, 2360102 Valpara´ıso, Chile 6Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580, USA Downloaded from Accepted 2014 July 6. Received 2014 July 5; in original form 2014 May 13 ABSTRACT Over six years of operation, the Catalina Real-time Transient Survey (CRTS) has identified http://mnras.oxfordjournals.org/ 1043 cataclysmic variable (CV) candidates – the largest sample of CVs from a single survey to date. Here, we provide spectroscopic identification of 85 systems fainter than g ≥ 19, including three AM Canum Venaticorum binaries, one helium-enriched CV, one polar and one new eclipsing CV. We analyse the outburst properties of the full sample and show that it contains a large fraction of low-accretion-rate CVs with long outburst recurrence times. We argue that most of the high-accretion-rate dwarf novae in the survey footprint have already been found and that future CRTS discoveries will be mostly low-accretion-rate systems.
    [Show full text]
  • A Photometric and Spectroscopic Study of the Cataclysmic Variable Sx Leonis Minoris in Quiescence and Superoutburst1 R
    THE ASTRONOMICAL JOURNAL, 115:787È800, 1998 February ( 1998. The American Astronomical Society. All rights reserved. Printed in U.S.A. A PHOTOMETRIC AND SPECTROSCOPIC STUDY OF THE CATACLYSMIC VARIABLE SX LEONIS MINORIS IN QUIESCENCE AND SUPEROUTBURST1 R. MARK WAGNER,2 JOHN R.THORSTENSEN,3 R. K.HONEYCUTT,4 S. B.HOWELL,5 R. H. KAITCHUCK,6 T. J.KREIDL,7 J. W.ROBERTSON,4 E. M. SION,8 AND S. G. STARRFIELD9 Received 1996 December 17; revised 1997 October 27 ABSTRACT We present CCD imaging, CCD photometry on long and short timescales, and time-resolved spectros- copy of SX LMi, a new SU Ursae Majoris type dwarf nova. The quiescent optical spectrum shows broad double-peaked Balmer, He I, and He II emission lines, similar to other quiescent dwarf novae. Absorption lines from a late-type secondary are not detected. Time-resolved spectra obtained in quies- cence reveal radial velocity variations of the Balmer emission lines on a period of 0.06717 ^ 0.00011 days, or 96.72 ^ 0.16 minutes, with only a slight possibility of a daily cycle-count error. Optical photometry obtained between 1987 and 1991 shows Ñickering with a peak-to-peak amplitude of ^0.18 mag. The binary orbital period can sometimes be seen in the photometric record. Long-term photometric monitor- ing by Indiana UniversityÏs robotic telescope RoboScope for a 3 year period between 1992 October and 1995 June shows seven well-deÐned outbursts and marginally detects a few others. The outburst interval varies between 34 and 64 days. During the 1994 December outburst, optical photometric observations show that SX LMi exhibited superhumps with a period of 0.06893 ^ 0.00012 days, which is 2.6% ^ 0.2% longer than the orbital period, as expected for a normal SU UMa star at this period.
    [Show full text]
  • Superwasp Observations of Long Timescale Photometric Variations in Cataclysmic Variables
    A&A 514, A30 (2010) Astronomy DOI: 10.1051/0004-6361/200912650 & c ESO 2010 Astrophysics SuperWASP observations of long timescale photometric variations in cataclysmic variables N. L. Thomas1,A.J.Norton1, D. Pollacco2,R.G.West3,P.J.Wheatley4, B. Enoch5, and W. I. Clarkson6 1 Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA, UK e-mail: [email protected] 2 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University, University Road, Belfast BT7 1NN, UK 3 Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK 4 Department of Physics, University of Warwick, Coventry CV4 7AL, UK 5 SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St. Andrews, Fife KY16 9SS, UK 6 STScI, 3700 San Martin Drive, Baltimore, MD 21218, USA Received 7 June 2009 / Accepted 26 January 2010 ABSTRACT Aims. We investigated whether the predictions and results of Stanishev et al. (2002, A&A, 394, 625) concerning a possible relation- ship between eclipse depths in PX And and its retrograde disc precession phase, could be confirmed in long term observations made by SuperWASP. In addition, two further CVs (DQ Her and V795 Her) in the same SuperWASP data set were investigated to see whether evidence of superhump periods and disc precession periods were present and what other, if any, long term periods could be detected. Methods. Long term photometry of PX And, V795 Her and DQ Her was carried out and Lomb-Scargle periodogram analysis under- taken on the resulting light curves. For the two eclipsing CVs, PX And and DQ Her, we analysed the potential variations in the depth of the eclipse with cycle number.
    [Show full text]
  • Arxiv:1810.09864V2 [Astro-Ph.SR] 6 Nov 2018
    Manuscript for Revista Mexicana de Astronomía y Astrofísica (2007) EXTENSIVE PHOTOMETRY OF V1838 AQL DURING THE 2013 SUPEROUTBURST J. Echevarría1, E. de Miguel2, J. V. Hernández Santisteban3, R. Michel4, R. Costero1, L. J. Sánchez1, A. Ruelas-Mayorga1, J. Olivares5, D. González-Buitrago6, J.L. Jones7, A. Oskanen8, W. Goff9, J. Ulowetz10, G. Bolt11, R. Sabo12, F.-J Hambsch13, D. Slauson14, and W. Stein15 Draft version: September 6, 2021 RESUMEN Presentamos un estudio fotométrico detallado de la super-erupción de V1838 Aql, una variable cataclísmica recientemente descubierta, desde el máx- imo en 2013 hasta su regreso al mínimo. Examinamos en detalle la evolución de los superhumps. Determinamos el período orbital Porb = 0:05698(9) d a partir de la periodicidad de los superhumps tempranos. Comparando los períodos de superhumps en las etapas A y B con el valor del período orbital, derivamos un valor del cambio en el período orbital de = 0:024(2) y un cociente de masa para el sistema de q = 0:10(1). Sugerimos que V1838 Aql se está acercando al mínimo período orbital, por lo que la secundaria sería una estrella de baja masa y no un objeto sub-estelar. ABSTRACT We present an in-depth photometric study of the 2013 superoutburst of the recently discovered cataclysmic variable V1838 Aql and subsequent pho- tometry near its quiescent state. A careful examination of the development of the superhumps is presented. Our best determination of the orbital period is Porb = 0:05698(9) days, based on the periodicity of early superhumps. Com- paring the superhump periods at stages A and B with the early superhump 1Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70-264, Ciudad Universitaria, México D.F., C.P.
    [Show full text]
  • SAS-2019 the Symposium on Telescope Science
    Proceedings for the 38th Annual Conference of the Society for Astronomical Sciences SAS-2019 The Symposium on Telescope Science Joint Meeting with the Center for Backyard Astrophysics Editors: Robert K. Buchheim Robert M. Gill Wayne Green John C. Martin John Menke Robert Stephens May, 2019 Ontario, CA i Disclaimer The acceptance of a paper for the SAS Proceedings does not imply nor should it be inferred as an endorsement by the Society for Astronomical Sciences of any product, service, method, or results mentioned in the paper. The opinions expressed are those of the authors and may not reflect those of the Society for Astronomical Sciences, its members, or symposium Sponsors Published by the Society for Astronomical Sciences, Inc. Rancho Cucamonga, CA First printing: May 2019 Photo Credits: Front Cover: NGC 2024 (Flame Nebula) and B33 (Horsehead Nebula) Alson Wong, Center for Solar System Studies Back Cover: SA-200 Grism spectrum of Wolf-Rayet star HD214419 Forrest Sims, Desert Celestial Observatory ii TABLE OF CONTENTS PREFACE v SYMPOSIUM SPONSORS vi SYMPOSIUM SCHEDULE viii PRESENTATION PAPERS Robert D. Stephens, Brian D. Warner THE SEARCH FOR VERY WIDE BINARY ASTEROIDS 1 Tom Polakis LESSONS LEARNED DURING THREE YEARS OF ASTEROID PHOTOMETRY 7 David Boyd SUDDEN CHANGE IN THE ORBITAL PERIOD OF HS 2325+8205 15 Tom Kaye EXOPLANET DETECTION USING BRUTE FORCE TECHNIQUES 21 Joe Patterson, et al FORTY YEARS OF AM CANUM VENATICORIUM 25 Robert Denny ASCOM – NOT JUST FOR WINDOWS ANY MORE 31 Kalee Tock HIGH ALTITUDE BALLOONING 33 William Rust MINIMIZING DISTORTION IN TIME EXPOSED CELESTIAL IMAGES 43 James Synge PROJECT PANOPTES 49 Steve Conard, et al THE USE OF FIXED OBSERVATORIES FOR FAINT HIGH VALUE OCCULTATIONS 51 John Martin, Logan Kimball UPDATE ON THE M31 AND M33 LUMINOUS STARS SURVEY 53 John Morris CURRENT STATUS OF “VISUAL” COMET PHOTOMETRY 55 Joe Patterson, et al ASASSN-18EY = MAXIJ1820+070 = “MAXIE”: KING OF THE BLACK HOLE 61 SUPERHUMPS Richard Berry IMAGING THE MOON AT THERMAL INFRARED WAVELENGTHS 67 iii Jerrold L.
    [Show full text]
  • Pos(HTRA-IV)023 , 1 , 9 , B.T
    ULTRACAM observations of SDS 0926+3624: the first known eclipsing AM CVn star PoS(HTRA-IV)023 C.M. Copperwheat∗ Department of Physics, University of Warwick, Coventry, CV4 7AL, UK E-mail: [email protected] T.R. Marsh1, S.P. Littlefair2, V.S. Dhillon2, G. Ramsay3, A.J. Drake4, B.T. Gänsicke1, P.J. Groot5, P. Hakala6, D. Koester7, G. Nelemans5, G. Roelofs8, J. Southworth9, D. Steeghs1 and S. Tulloch2 1 Department of Physics, University of Warwick, Coventry, CV4 7AL, UK 2 Department of Physics and Astronomy, University of Sheffield, S3 7RH, UK 3 Armagh Observatory, College Hill, Armagh, BT61 9DG, UK 4 California Institute of Technology, 1200 E. California Blvd., CA 91225, USA 5 Department of Astrophysics, IMAPP, Radboud University Nijmegen, PO Box 9010, NL-6500 GL Nijmegen, the Netherlands 6 Finnish Centre for Astronomy with ESO, Tuorla Observatory, Väisäläntie 20, FIN-21500 Piikkiö, University of Turku, Finland 7 Institut für Theoretische Physik und Astrophysik, Universität Kiel, 24098 Kiel, Germany 8 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 9 Astrophysics Group, Keele University, Newcastle-under-Lyme, ST5 5BG, UK The AM Canum Venaticorum (AM CVn) stars are ultracompact binaries with the lowest periods of any binary subclass, and consist of a white dwarf accreting material from a donor star that is it- self fully or partially degenerate. These objects offer new insight into the formation and evolution of binary systems, and are predicted to be among the strongest gravitational wave sources in the sky. To date, the only known eclipsing source of this type is the 28 min binary SDSS 0926+3624.
    [Show full text]
  • Prof. Tansel AK
    Prof. Tansel AK OPfefricseo Pnhaol nIen:f +or9m0 2a1t2io 4n40 0000 Extension: 10296 EFmaxa iPl:h otannes:e l+ak9@0 i2st1a2n b4u4l0.e 0d3u7.t0r AWdedbr:e hstst:p :İ/s/tawnwbuwl. iÜstnainvebrusli.etedsui .Ftre/nfe Fna/kpüelrtessoin Aeslatrkoanfeonm.pi hvpe? Uidz=ay2 6B9ilimleri Bölümü, 34119, Üniversite, Beyazıt, İstanbul EDodcutocraatteio, İnst aInnbfuol rÜmniavetriosintesi, Institute of Graduate Studies In Sciences, Astronomi Ve Uzay Bilimleri Anabilim Dalı, PTousrtkgerya d1u9a9t2e ,- İ1st9a9n9bul Üniversitesi, Institute of Graduate Studies In Sciences, Astronomi Ve Uzay Bilimleri Anabilim Dalı, UTunrdkeeryg r1a9d9u0a t-e 1, 9İs9ta2nbul Üniversitesi, Faculty of Science, Astronomy and Space Sciences, Turkey 1983 - 1990 FEnogrliesihg, nB2 L Uapnpgeru Iangteersmediate Dissertations ADsotcrtoonroamtei, CVüec Uez Nayo vBaillaimrılne rUi zAunna Dbiölinme mDalil ıD, 1av9r9a9nışları, Istanbul University, Institute of Graduate Studies In Sciences, SPcoisetngcreasd, uYaıltdeı,z K Aatmakolissfmerilke rDi ePğrioşegnra DmQı, H1e9r9 2Yıldızının Morötesi Tayfı, Istanbul University, Institute of Graduate Studies In RPheysseicas,r Acshtr Aonroemays and Astrophysics, Astronomy and Astrophysics: Instrumentation Techniques and Observations, Star Scyisetnecmess, Interstellar Medium, The Galaxy, Galactic and Extragalactic Objets and Systems, Cosmology, Stars, Natural Academic Titles / Tasks APrsosofecsiastoer ,P Irsotafensbsuolr U, Insitvaenrbsuitly U, Fnaivceurltsyit yo,f FSaccieunltcye o, Af sStcrioencoem, Ay satnrodn Sopmacye a Sncdie Snpcaecse, 2S0c1ie2n
    [Show full text]
  • Appendix: Spectroscopy of Variable Stars
    Appendix: Spectroscopy of Variable Stars As amateur astronomers gain ever-increasing access to professional tools, the science of spectroscopy of variable stars is now within reach of the experienced variable star observer. In this section we shall examine the basic tools used to perform spectroscopy and how to use the data collected in ways that augment our understanding of variable stars. Naturally, this section cannot cover every aspect of this vast subject, and we will concentrate just on the basics of this field so that the observer can come to grips with it. It will be noticed by experienced observers that variable stars often alter their spectral characteristics as they vary in light output. Cepheid variable stars can change from G types to F types during their periods of oscillation, and young variables can change from A to B types or vice versa. Spec­ troscopy enables observers to monitor these changes if their instrumentation is sensitive enough. However, this is not an easy field of study. It requires patience and dedication and access to resources that most amateurs do not possess. Nevertheless, it is an emerging field, and should the reader wish to get involved with this type of observation know that there are some excellent guides to variable star spectroscopy via the BAA and the AAVSO. Some of the workshops run by Robin Leadbeater of the BAA Variable Star section and others such as Christian Buil are a very good introduction to the field. © Springer Nature Switzerland AG 2018 M. Griffiths, Observer’s Guide to Variable Stars, The Patrick Moore 291 Practical Astronomy Series, https://doi.org/10.1007/978-3-030-00904-5 292 Appendix: Spectroscopy of Variable Stars Spectra, Spectroscopes and Image Acquisition What are spectra, and how are they observed? The spectra we see from stars is the result of the complete output in visible light of the star (in simple terms).
    [Show full text]
  • Annual Report / Rapport Annuel / Jahresbericht 1996
    Annual Report / Rapport annuel / Jahresbericht 1996 ✦ ✦ ✦ E U R O P E A N S O U T H E R N O B S E R V A T O R Y ES O✦ 99 COVER COUVERTURE UMSCHLAG Beta Pictoris, as observed in scattered light Beta Pictoris, observée en lumière diffusée Beta Pictoris, im Streulicht bei 1,25 µm (J- at 1.25 microns (J band) with the ESO à 1,25 microns (bande J) avec le système Band) beobachtet mit dem adaptiven opti- ADONIS adaptive optics system at the 3.6-m d’optique adaptative de l’ESO, ADONIS, au schen System ADONIS am ESO-3,6-m-Tele- telescope and the Observatoire de Grenoble télescope de 3,60 m et le coronographe de skop und dem Koronographen des Obser- coronograph. l’observatoire de Grenoble. vatoriums von Grenoble. The combination of high angular resolution La combinaison de haute résolution angu- Die Kombination von hoher Winkelauflö- (0.12 arcsec) and high dynamical range laire (0,12 arcsec) et de gamme dynamique sung (0,12 Bogensekunden) und hohem dy- (105) allows to image the disk to only 24 AU élevée (105) permet de reproduire le disque namischen Bereich (105) erlaubt es, die from the star. Inside 50 AU, the main plane jusqu’à seulement 24 UA de l’étoile. A Scheibe bis zu einem Abstand von nur 24 AE of the disk is inclined with respect to the l’intérieur de 50 UA, le plan principal du vom Stern abzubilden. Innerhalb von 50 AE outer part. Observers: J.-L. Beuzit, A.-M.
    [Show full text]
  • Arxiv:2003.02360V2 [Astro-Ph.HE] 4 Apr 2020 Datsu Et Al
    Draft version April 7, 2020 Typeset using LATEX twocolumn style in AASTeX62 THE BINARY MASS RATIO IN THE BLACK HOLE TRANSIENT MAXI J1820+070 M. A. P. Torres,1, 2 J. Casares,1, 2 F. Jimenez-Ibarra,´ 1, 2 A. Alvarez-Hern´ andez´ ,1, 2 T. Munoz-Darias~ ,1, 2 M. Armas Padilla,1, 2 P.G. Jonker,3, 4 and M. Heida5 1Instituto de Astrof´ısica de Canarias, E-38205 La Laguna, Tenerife, Spain 2Departamento de Astrof´ısica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain 3SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, NL-3584 CA Utrecht, the Netherlands 4Department of Astrophysics/IMAPP, Radboud University, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands 5ESO, Karl-Schwarzschild-Str 2, 85748 Garching bei Mnchen, Germany (Received April 7, 2020) ABSTRACT We present intermediate resolution spectroscopy of the optical counterpart to the black hole X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained with the OSIRIS spectrograph on the 10.4-m Gran Telescopio Canarias. The observations were performed with the source close to the quiescent state and before the onset of renewed activity in August 2019. We make use of these data and K-type dwarf templates taken with the same instrumental configuration to measure the projected rotational −1 velocity of the donor star. We find vrot sin i = 84±5 km s (1−σ), which implies a donor to black-hole mass ratio q = M2=M1 = 0:072 ± 0:012 for the case of a tidally locked and Roche-lobe filling donor −3 star. The derived dynamical masses for the stellar components are M1 = (5:95 ± 0:22) sin i M and −3 M2 = (0:43 ± 0:08) sin i M .
    [Show full text]
  • Cataclysmic Variables
    Cataclysmic variables Article (Accepted Version) Smith, Robert Connon (2006) Cataclysmic variables. Contemporary Physics, 47 (6). pp. 363-386. ISSN 0010-7514 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/2256/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk Cataclysmic variables Robert Connon Smith Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH, UK E-mail: [email protected] Abstract. Cataclysmic variables are binary stars in which a relatively normal star is transferring mass to its compact companion.
    [Show full text]