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The Very Long Mystery of Epsilon Aurigae
A Unique Eclipsing Variable TheThe VeryVery LongLong MMysteryystery ofof EpsilonEpsilon AAurigaeurigae robertrobert e. sstenceltencel one of the great scientifi c advances of the 20th A remarkable naked-eye star century was the theory of stellar evolution, as physicists worked out not just how stars shine, but how they origi- will soon start dimming for nate, live, change, and die. To test theory against reality, however, astronomers had to determine accurate masses the eighth time since 1821. for many diff erent kinds of stars — and this meant analyz- What’s going on is still ing the motions of binary pairs. Theorists also needed the stars’ exact diameters, and this meant analyzing the light not exactly clear. curves of eclipsing binaries in particular. A century ago, S&T ILLUSTRATION BY CASEY REED giants of early astrophysics worked intensely on the prob- lem of eclipsing-binary analysis. Henry Norris Russell’s paper “On the Determination of the Orbital Elements of Eclipsing Variable Stars,” published in 1912, set the stage for what followed. BIG WHITE STAR, BIGGER BLACK PARTNER Epsilon Aurigae, hotter than the Sun and larger than Earth’s entire orbit, pours forth some 130,000 times the Sun’s light — which is why it shines as brightly as 3rd magnitude even from 2,000 light-years away. According to the currently favored model, a long, dark object will start sliding across its middle this summer. The object seems to be an opaque warped disk 10 a.u. wide and appearing roughly 1 a.u. tall. Whatever lies at its center seems to be hidden — though there’s also evidence that we see right through the center. -
Radio Images of a Large Stellar Coronal Loop on Algol
Radio Images of A Large Stellar Coronal Loop on Algol W. M. Peterson*, R. L. Mutel*, M. Gudel**,¨ W. M. Goss† *Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, Iowa 52240, USA **ETH Zurich, Institute of Astronomy, 8093 Zurich, Switzerland †National Radio Astronomy Observatory, Pete V. Domenici Science Operations Center, 1003 Lopezville Road, Socorro, New Mexico 87801, USA The close binary Algol contains a radio-bright K subgiant star in a very close (0.062 AU), rapid (2.86 day) orbit with a main sequence B8 star. Since the rotation periods of the two stars are tidally locked to the orbital period, the consequent rapid rotation drives a robust magnetic dynamo. A large body of evidence points to the existence of an extended, complex coronal magnetosphere originating at the cooler K subgiant1–4. The detailed morphology of the subgiant’s corona and its possible interaction with its companion are unknown, though theory predicts that the coronal plasma should be confined in magnetic loop structure5, as seen on the Sun. Here we report multi-epoch radio imaging of the Algol system, in which we see a large, persistent coronal loop approximately one subgiant diameter in height, whose base is straddling the subgiant and whose apex is oriented toward the B star. This strongly suggests that a persistent asymmetric magnetic field structure is aligned between the two stars. The loop is larger than anticipated theoretically6, 7, but the size may be a result of a magnetic interaction between the two stars. 1 We made six twelve-hour observations of Algol during a period from 6 April to 17 August 2008 with the High Sensitivity Array (HSA), a global very long baseline interferometer array. -
Accretion Flows in Nonmagnetic White Dwarf Binaries As Observed in X-Rays
Accretion Flows in Nonmagnetic White Dwarf Binaries as Observed in X-rays Şölen Balmana,< aKadir Has University, Faculty of Engineering and Natural Sciences, Cibali 34083, Istanbul, Turkey ARTICLEINFO ABSTRACT Keywords: Cataclysmic Variables (CVs) are compact binaries with white dwarf (WD) primaries. CVs and other cataclysmic variables - accretion, accre- accreting WD binaries (AWBs) are useful laboratories for studying accretion flows, gas dynamics, tion disks - thermal emission - non-thermal outflows, transient outbursts, and explosive nuclear burning under different astrophysical plasma con- emission - white dwarfs - X-rays: bina- ditions. They have been studied over decades and are important for population studies of galactic ries X-ray sources. Recent space- and ground-based high resolution spectral and timing studies, along with recent surveys indicate that we still have observational and theoretical complexities yet to an- swer. I review accretion in nonmagnetic AWBs in the light of X-ray observations. I present X-ray diagnostics of accretion in dwarf novae and the disk outbursts, the nova-like systems, and the state of the research on the disk winds and outflows in the nonmagnetic CVs together with comparisons and relations to classical and recurrent nova systems, AM CVns and Symbiotic systems. I discuss how the advective hot accretion flows (ADAF-like) in the inner regions of accretion disks (merged with boundary layer zones) in nonmagnetic CVs explain most of the discrepancies and complexities that have been encountered in the X-ray observations. I stress how flickering variability studies from optical to X-rays can be probes to determine accretion history and disk structure together with how the temporal and spectral variability of CVs are related to that of LMXBs and AGNs. -
Winter Constellations
Winter Constellations *Orion *Canis Major *Monoceros *Canis Minor *Gemini *Auriga *Taurus *Eradinus *Lepus *Monoceros *Cancer *Lynx *Ursa Major *Ursa Minor *Draco *Camelopardalis *Cassiopeia *Cepheus *Andromeda *Perseus *Lacerta *Pegasus *Triangulum *Aries *Pisces *Cetus *Leo (rising) *Hydra (rising) *Canes Venatici (rising) Orion--Myth: Orion, the great hunter. In one myth, Orion boasted he would kill all the wild animals on the earth. But, the earth goddess Gaia, who was the protector of all animals, produced a gigantic scorpion, whose body was so heavily encased that Orion was unable to pierce through the armour, and was himself stung to death. His companion Artemis was greatly saddened and arranged for Orion to be immortalised among the stars. Scorpius, the scorpion, was placed on the opposite side of the sky so that Orion would never be hurt by it again. To this day, Orion is never seen in the sky at the same time as Scorpius. DSO’s ● ***M42 “Orion Nebula” (Neb) with Trapezium A stellar nursery where new stars are being born, perhaps a thousand stars. These are immense clouds of interstellar gas and dust collapse inward to form stars, mainly of ionized hydrogen which gives off the red glow so dominant, and also ionized greenish oxygen gas. The youngest stars may be less than 300,000 years old, even as young as 10,000 years old (compared to the Sun, 4.6 billion years old). 1300 ly. 1 ● *M43--(Neb) “De Marin’s Nebula” The star-forming “comma-shaped” region connected to the Orion Nebula. ● *M78--(Neb) Hard to see. A star-forming region connected to the Orion Nebula. -
Správa O Činnosti Organizácie SAV Za Rok 2017
Astronomický ústav SAV Správa o činnosti organizácie SAV za rok 2017 Tatranská Lomnica január 2018 Obsah osnovy Správy o činnosti organizácie SAV za rok 2017 1. Základné údaje o organizácii 2. Vedecká činnosť 3. Doktorandské štúdium, iná pedagogická činnosť a budovanie ľudských zdrojov pre vedu a techniku 4. Medzinárodná vedecká spolupráca 5. Vedná politika 6. Spolupráca s VŠ a inými subjektmi v oblasti vedy a techniky 7. Spolupráca s aplikačnou a hospodárskou sférou 8. Aktivity pre Národnú radu SR, vládu SR, ústredné orgány štátnej správy SR a iné organizácie 9. Vedecko-organizačné a popularizačné aktivity 10. Činnosť knižnično-informačného pracoviska 11. Aktivity v orgánoch SAV 12. Hospodárenie organizácie 13. Nadácie a fondy pri organizácii SAV 14. Iné významné činnosti organizácie SAV 15. Vyznamenania, ocenenia a ceny udelené organizácii a pracovníkom organizácie SAV 16. Poskytovanie informácií v súlade so zákonom o slobodnom prístupe k informáciám 17. Problémy a podnety pre činnosť SAV PRÍLOHY A Zoznam zamestnancov a doktorandov organizácie k 31.12.2017 B Projekty riešené v organizácii C Publikačná činnosť organizácie D Údaje o pedagogickej činnosti organizácie E Medzinárodná mobilita organizácie F Vedecko-popularizačná činnosť pracovníkov organizácie SAV Správa o činnosti organizácie SAV 1. Základné údaje o organizácii 1.1. Kontaktné údaje Názov: Astronomický ústav SAV Riaditeľ: Mgr. Martin Vaňko, PhD. Zástupca riaditeľa: Mgr. Peter Gömöry, PhD. Vedecký tajomník: Mgr. Marián Jakubík, PhD. Predseda vedeckej rady: RNDr. Luboš Neslušan, CSc. Člen snemu SAV: Mgr. Marián Jakubík, PhD. Adresa: Astronomický ústav SAV, 059 60 Tatranská Lomnica http://www.ta3.sk Tel.: 052/7879111 Fax: 052/4467656 E-mail: [email protected] Názvy a adresy detašovaných pracovísk: Astronomický ústav - Oddelenie medziplanetárnej hmoty Dúbravská cesta 9, 845 04 Bratislava Vedúci detašovaných pracovísk: Astronomický ústav - Oddelenie medziplanetárnej hmoty prof. -
Red Giant Mass-Loss: Studying Evolved Stellar Winds with FUSE and HST/STIS
Red Giant Mass-Loss: Studying Evolved Stellar Winds with FUSE and HST/STIS A dissertation submitted to the University of Dublin for the degree of Doctor of Philosophy Cian Crowley Supervisor: Dr. Brian R. Espey Trinity College Dublin, July 2006 School of Physics University of Dublin Trinity College Dublin ii For Mam and Dad Declaration I hereby declare that this thesis has not been submitted as an exercise for a degree at this or any other University and that it is entirely my own work. I agree that the Library may lend or copy this thesis upon request. Signed, Cian Crowley July 25, 2006. Publications Crowley, C., Espey, B. R.,. & McCandliss, S. R., 2006, In prep., ‘FUSE and HST/STIS Observations of the Eclipsing Symbiotic Binary EG Andromedae’ Acknowledgments I wish to acknowledge and thank Brian Espey, Stephan McCandliss and Peter Hauschildt for their contributions to this work. Most especially I would like to express my gratitude to my supervisor Brian Espey for his enthusiastic supervision, patience and encourage- ment. His help, support and advice is very much appreciated. In addition, the helpful and insightful comments and advice from numerous people, inlcuding, Graham Harper, Philip Bennett, Alex Brown, Gary Ferland, Tom Ake, B-G Anderson and Dugan With- erick, were invaluable and again, very much appreciated. Also, a special word of thanks for their viva comments and feedback for Alex Brown and Peter Gallagher. This work was supported by Enterprise Ireland Basic Research grant SC/2002/370 from EU funded NDP. The FUSE data were obtained under the Guest Investigator Pro- gram and supported by NASA grants NAG5-8994 and NAG5-10403 to the Johns Hopkins University (JHU). -
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. -
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. -
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. -
121012-AAS-221 Program-14-ALL, Page 253 @ Preflight
221ST MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY 6-10 January 2013 LONG BEACH, CALIFORNIA Scientific sessions will be held at the: Long Beach Convention Center 300 E. Ocean Blvd. COUNCIL.......................... 2 Long Beach, CA 90802 AAS Paper Sorters EXHIBITORS..................... 4 Aubra Anthony ATTENDEE Alan Boss SERVICES.......................... 9 Blaise Canzian Joanna Corby SCHEDULE.....................12 Rupert Croft Shantanu Desai SATURDAY.....................28 Rick Fienberg Bernhard Fleck SUNDAY..........................30 Erika Grundstrom Nimish P. Hathi MONDAY........................37 Ann Hornschemeier Suzanne H. Jacoby TUESDAY........................98 Bethany Johns Sebastien Lepine WEDNESDAY.............. 158 Katharina Lodders Kevin Marvel THURSDAY.................. 213 Karen Masters Bryan Miller AUTHOR INDEX ........ 245 Nancy Morrison Judit Ries Michael Rutkowski Allyn Smith Joe Tenn Session Numbering Key 100’s Monday 200’s Tuesday 300’s Wednesday 400’s Thursday Sessions are numbered in the Program Book by day and time. Changes after 27 November 2012 are included only in the online program materials. 1 AAS Officers & Councilors Officers Councilors President (2012-2014) (2009-2012) David J. Helfand Quest Univ. Canada Edward F. Guinan Villanova Univ. [email protected] [email protected] PAST President (2012-2013) Patricia Knezek NOAO/WIYN Observatory Debra Elmegreen Vassar College [email protected] [email protected] Robert Mathieu Univ. of Wisconsin Vice President (2009-2015) [email protected] Paula Szkody University of Washington [email protected] (2011-2014) Bruce Balick Univ. of Washington Vice-President (2010-2013) [email protected] Nicholas B. Suntzeff Texas A&M Univ. suntzeff@aas.org Eileen D. Friel Boston Univ. [email protected] Vice President (2011-2014) Edward B. Churchwell Univ. of Wisconsin Angela Speck Univ. of Missouri [email protected] [email protected] Treasurer (2011-2014) (2012-2015) Hervey (Peter) Stockman STScI Nancy S. -
134, December 2007
British Astronomical Association VARIABLE STAR SECTION CIRCULAR No 134, December 2007 Contents AB Andromedae Primary Minima ......................................... inside front cover From the Director ............................................................................................. 1 Recurrent Objects Programme and Long Term Polar Programme News............4 Eclipsing Binary News ..................................................................................... 5 Chart News ...................................................................................................... 7 CE Lyncis ......................................................................................................... 9 New Chart for CE and SV Lyncis ........................................................ 10 SV Lyncis Light Curves 1971-2007 ............................................................... 11 An Introduction to Measuring Variable Stars using a CCD Camera..............13 Cataclysmic Variables-Some Recent Experiences ........................................... 16 The UK Virtual Observatory ......................................................................... 18 A New Infrared Variable in Scutum ................................................................ 22 The Life and Times of Charles Frederick Butterworth, FRAS........................24 A Hard Day’s Night: Day-to-Day Photometry of Vega and Beta Lyrae.........28 Delta Cephei, 2007 ......................................................................................... 33 -
Infrared Studies of Epsilon Aurigae in Eclipse
The Astronomical Journal, 142:174 (9pp), 2011 November doi:10.1088/0004-6256/142/5/174 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. INFRARED STUDIES OF EPSILON AURIGAE IN ECLIPSE Robert E. Stencel1, Brian K. Kloppenborg1, Randall E. Wall, Jr.1, Jeffrey L. Hopkins2, Steve B. Howell3, D. W. Hoard4, John Rayner5, Schelte Bus5, Alan Tokunaga5, Michael L. Sitko6,7, Suellen Bradford6,7, Ray W. Russell8, David K. Lynch8, Heidi Hammel9, Barbara Whitney9, Glenn Orton10, Padma Yanamandra-Fisher10, Joseph L. Hora11,PhilipHinz12, William Hoffmann12, and Andrew Skemer12 1 Department of Physics & Astronomy, University of Denver, Denver, CO 80208 USA; [email protected] 2 Hopkins Phoenix Observatory, Phoenix, AZ 85033 USA 3 National Optical Astronomy Observatories, Tucson, AZ 85719, USA 4 Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125, USA 5 Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA 6 Department of Physics, Cincinnati University, Cincinnati, OH, USA 7 Space Science Institute, Boulder, CO, USA 8 The Aerospace Corporation, Los Angeles, CA 90009, USA 9 Space Science Institute, Boulder, CO 80301, USA 10 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA 11 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 12 Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721, USA Received 2011 July 7; accepted 2011 September 16; published 2011 October 17 ABSTRACT We report here on a series of medium resolution spectro-photometric observations of the enigmatic long period eclipsing binary epsilon Aurigae, during its eclipse interval of 2009–2011, using near-infrared spectra obtained with SpeX on the Infrared Telescope Facility (IRTF), mid-infrared spectra obtained with BASS on AOES and IRTF, MIRSI on IRTF, and MIRAC4 on the MMT, along with mid-infrared photometry using MIRSI on IRTF and MIRAC4 on the MMT, plus 1995–2000 timeframe published photometry and data obtained with Denver’s TNTCAM2 at WIRO.