Prof. AHMET ERDEM
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Commission 27 of the Iau Information Bulletin
COMMISSION 27 OF THE I.A.U. INFORMATION BULLETIN ON VARIABLE STARS Nos. 2401 - 2500 1983 September - 1984 March EDITORS: B. SZEIDL AND L. SZABADOS, KONKOLY OBSERVATORY 1525 BUDAPEST, Box 67, HUNGARY HU ISSN 0374-0676 CONTENTS 2401 A POSSIBLE CATACLYSMIC VARIABLE IN CANCER Masaaki Huruhata 20 September 1983 2402 A NEW RR-TYPE VARIABLE IN LEO Masaaki Huruhata 20 September 1983 2403 ON THE DELTA SCUTI STAR BD +43d1894 A. Yamasaki, A. Okazaki, M. Kitamura 23 September 1983 2404 IQ Vel: IMPROVED LIGHT-CURVE PARAMETERS L. Kohoutek 26 September 1983 2405 FLARE ACTIVITY OF EPSILON AURIGAE? I.-S. Nha, S.J. Lee 28 September 1983 2406 PHOTOELECTRIC OBSERVATIONS OF 20 CVn Y.W. Chun, Y.S. Lee, I.-S. Nha 30 September 1983 2407 MINIMUM TIMES OF THE ECLIPSING VARIABLES AH Cep AND IU Aur Pavel Mayer, J. Tremko 4 October 1983 2408 PHOTOELECTRIC OBSERVATIONS OF THE FLARE STAR EV Lac IN 1980 G. Asteriadis, S. Avgoloupis, L.N. Mavridis, P. Varvoglis 6 October 1983 2409 HD 37824: A NEW VARIABLE STAR Douglas S. Hall, G.W. Henry, H. Louth, T.R. Renner 10 October 1983 2410 ON THE PERIOD OF BW VULPECULAE E. Szuszkiewicz, S. Ratajczyk 12 October 1983 2411 THE UNIQUE DOUBLE-MODE CEPHEID CO Aur E. Antonello, L. Mantegazza 14 October 1983 2412 FLARE STARS IN TAURUS A.S. Hojaev 14 October 1983 2413 BVRI PHOTOMETRY OF THE ECLIPSING BINARY QX Cas Thomas J. Moffett, T.G. Barnes, III 17 October 1983 2414 THE ABSOLUTE MAGNITUDE OF AZ CANCRI William P. Bidelman, D. Hoffleit 17 October 1983 2415 NEW DATA ABOUT THE APSIDAL MOTION IN THE SYSTEM OF RU MONOCEROTIS D.Ya. -
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. -
Variable Star Section Circular
ΒΑΛ The British Astronomical Association VARIABLE STAR SECTION CIRCULAR 64 "LIGHT-CURVE” AUGUST 1986 ISSN 0267-9272 Office: Burlington House, Piccadilly, London, W1V 9AG SECTION OFFICERS: Director D.R.B. Saw, 'Upanova1, 18 Dolllcott, Haddenham, Aylesbury, Bucks. HP17 8JG Tel: Haddenham (0844) 292065 Assistant Director S.R. Dunlop, 140 Stocks Lane, East Wittering, nr Chichester, West Sussex P020 8NT Tel: Bracklesham Bay (0243) 670354 Secretary M.D. Taylor, 17 Cross Lane, Wakefield, West Yorkshire WF2 8DA Tel: Wakefield (0924) 374651 Programme Secretaries: Assistant Secretary (Post temporarily vacant) Telescopic Assistant Secretary J. Toone, 2 Hilton Crescent, Boothstown, Binocular Worsley, Manchester M28 4FY Tel: 061 702 8619 Eclipsing Binary J.E. Isles, Rose Cottage, 22 High Street, Secretary Wescott, Bucks. HP18 OPU Tel: Aylesbury (0296) 651779 Nova/Supernova G.M Hurst, 16 Westminster Close, Search Secretary Kempshott Rise, Basingstoke, Hants. RG22 4PP Tel: Basingstoke (0256) 471074 Chart Secretary J. Parkinson, 229 Scar Lane, Golcar, (except Eclipsing) Huddersfield, West Yorkshire HD7 4AU Tel: Huddersfield (0484) 642947 For subcription rates and charges for charts and other publications see inside back cover. Editorial It has been suggested that these C irc u la rs are often a little 'dry' and technical for some members. We are always happy to receive more 'personal' items and hope to include more in future issues. We are also including an occasional short note on some of the terms encountered, and which may not be fully explained in some of the specific articles. The first such item appears on p.13. If you have any queries, however elementary, please send them in, and we shall do our best to provide the answers. -
Astrophysics in 2006 3
ASTROPHYSICS IN 2006 Virginia Trimble1, Markus J. Aschwanden2, and Carl J. Hansen3 1 Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575, Las Cumbres Observatory, Santa Barbara, CA: ([email protected]) 2 Lockheed Martin Advanced Technology Center, Solar and Astrophysics Laboratory, Organization ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304: ([email protected]) 3 JILA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder CO 80309: ([email protected]) Received ... : accepted ... Abstract. The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the universe) and others of which there are always many, like meteors and molecules, black holes and binaries. Keywords: cosmology: general, galaxies: general, ISM: general, stars: general, Sun: gen- eral, planets and satellites: general, astrobiology CONTENTS 1. Introduction 6 1.1 Up 6 1.2 Down 9 1.3 Around 10 2. Solar Physics 12 2.1 The solar interior 12 2.1.1 From neutrinos to neutralinos 12 2.1.2 Global helioseismology 12 2.1.3 Local helioseismology 12 2.1.4 Tachocline structure 13 arXiv:0705.1730v1 [astro-ph] 11 May 2007 2.1.5 Dynamo models 14 2.2 Photosphere 15 2.2.1 Solar radius and rotation 15 2.2.2 Distribution of magnetic fields 15 2.2.3 Magnetic flux emergence rate 15 2.2.4 Photospheric motion of magnetic fields 16 2.2.5 Faculae production 16 2.2.6 The photospheric boundary of magnetic fields 17 2.2.7 Flare prediction from photospheric fields 17 c 2008 Springer Science + Business Media. -
![Arxiv:0908.2624V1 [Astro-Ph.SR] 18 Aug 2009](https://docslib.b-cdn.net/cover/1870/arxiv-0908-2624v1-astro-ph-sr-18-aug-2009-1111870.webp)
Arxiv:0908.2624V1 [Astro-Ph.SR] 18 Aug 2009
Astronomy & Astrophysics Review manuscript No. (will be inserted by the editor) Accurate masses and radii of normal stars: Modern results and applications G. Torres · J. Andersen · A. Gim´enez Received: date / Accepted: date Abstract This paper presents and discusses a critical compilation of accurate, fun- damental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and α Centauri) that satisfy our criterion that the mass and radius of both stars be known to ±3% or better. All are non-interacting systems, so the stars should have evolved as if they were single. This sample more than doubles that of the earlier similar review by Andersen (1991), extends the mass range at both ends and, for the first time, includes an extragalactic binary. In every case, we have examined the original data and recomputed the stellar parameters with a consistent set of assumptions and physical constants. To these we add interstellar reddening, effective temperature, metal abundance, rotational velocity and apsidal motion determinations when available, and we compute a number of other physical parameters, notably luminosity and distance. These accurate physical parameters reveal the effects of stellar evolution with un- precedented clarity, and we discuss the use of the data in observational tests of stellar evolution models in some detail. Earlier findings of significant structural differences between moderately fast-rotating, mildly active stars and single stars, ascribed to the presence of strong magnetic and spot activity, are confirmed beyond doubt. We also show how the best data can be used to test prescriptions for the subtle interplay be- tween convection, diffusion, and other non-classical effects in stellar models. -
Hyperspace NASA BPP Program Books 8
Advanced Space Propulsion Concepts for Interstellar Travel Gregory V. Meholic [email protected] Planets HR 8799 140 LY 11/14/08 Updated 9/25/2019 1 Presentation Objectives and Caveats ▪ Provide a high-level, “evolutionary”, information-only overview of various propulsion technology concepts that, with sufficient development (i.e. $), may lead mankind to the stars. ▪ Only candidate concepts for a vehicle’s primary interstellar propulsion system will be discussed. No attitude control No earth-to-orbit launch No traditional electric systems No sail-based systems No beamed energy ▪ None of the following will be given, assumed or implied: Recommendations on specific mission designs Developmental timelines or cost estimates ▪ Not all propulsion options will be discussed – that would be impossible! 2 Chapters 1. The Ultimate Space Mission 2. The Solar System and Beyond 3. Challenges of Human Star Flight 4. “Rocket Science” Basics 5. Conventional Mass Ejection Propulsion Systems State-of-the-Art Possible Improvements 6. Alternative Mass Ejection Systems Nuclear Fission Nuclear Fusion Matter/Antimatter Other Concepts 7. Physics-Based Concepts Definitions and Things to Remember Space-Time Warp Drives Fundamental Force Coupling Alternate Dimension / Hyperspace NASA BPP Program Books 8. Closing Information 3 Chapter 1: The Ultimate Space Mission 4 The Ultimate Space Mission For humans to travel to the stars and return to Earth within a “reasonable fraction” (around 15 years) of a human lifetime. ▪ Why venture beyond our Solar System? Because we have to - humans love to explore!!! Visit the Kuiper Belt and the Oort Cloud – Theoretical home to long-period comets Investigate the nature of the interstellar medium and its influence on the solar system (and vice versa) – Magnetic fields, low-energy galactic cosmic rays, composition, etc. -
FY13 High-Level Deliverables
National Optical Astronomy Observatory Fiscal Year Annual Report for FY 2013 (1 October 2012 – 30 September 2013) Submitted to the National Science Foundation Pursuant to Cooperative Support Agreement No. AST-0950945 13 December 2013 Revised 18 September 2014 Contents NOAO MISSION PROFILE .................................................................................................... 1 1 EXECUTIVE SUMMARY ................................................................................................ 2 2 NOAO ACCOMPLISHMENTS ....................................................................................... 4 2.1 Achievements ..................................................................................................... 4 2.2 Status of Vision and Goals ................................................................................. 5 2.2.1 Status of FY13 High-Level Deliverables ............................................ 5 2.2.2 FY13 Planned vs. Actual Spending and Revenues .............................. 8 2.3 Challenges and Their Impacts ............................................................................ 9 3 SCIENTIFIC ACTIVITIES AND FINDINGS .............................................................. 11 3.1 Cerro Tololo Inter-American Observatory ....................................................... 11 3.2 Kitt Peak National Observatory ....................................................................... 14 3.3 Gemini Observatory ........................................................................................ -
San Diego Astronomy Association Celebrating 40 Years of Astronomical Outreach
San Diego Astronomy Association Celebrating 40 Years of Astronomical Outreach Office (619) 645-8940 Observatory (619) 766-9118 The Scales http://www.sdaa.org by Scott Baker A Non-Profit Educational Association P.O. Box 23215, San Diego, CA 92193-3215 This month’s constellation is Libra “The Scales”. In ancient times, the great civilizations of the time had different ideas about SDAA Business Meeting Libra. The Greeks, didn’t see scales they considered this portion Will be held at: of the sky part of Scorpius. As a matter of fact, the two bright- SKF Condition Monitoring est stars in the constellation, Alpha and Beta Librae, have names 5271 Viewridge Court San Diego, CA 92123 that refer back to the constellation of Scorpius. They are known May 11th at 7:00pm as Zubenelgenubi and Zubeneschamalia, which are derivations of older Arabic names that translate into “Southern Claw” (i.e. of Program Meeting the Scorpion) for Alpha Librae and “The Northern Claw” for Beta June 16th at 7:00PM Librae. Showing of the film The Romans however, saw a scale or balance in the constella- “Universe: tion, and so named it Libra. They felt the constellation was impor- The Cosmology Quest” tant enough to give a place in the twelve Zodiacal Constellations, and is the only constellation of the Zodiac that represents and Mission Trails Regional Park Visitor & Interpretive Center inanimate object. Why so important you ask? 4000 years ago, 1 Father Junipero Serra Trail the sun, when entering Libra, marked the beginning of autumn, San Diego, CA 92119 Snacks ∗ Prizes ∗ Info ∗ Fun Doors open at 6:30PM See page 6 for details CONTENTS June 2004 Vol. -
Libra (Astrology) - Wikipedia, the Free Encyclopedia
מַ זַל מֹאזְ נַיִם http://www.morfix.co.il/en/Libra بُ ْر ُج ال ِميزان http://www.arabdict.com/en/english-arabic/Libra برج ِمي َزان https://translate.google.com/#en/fa/Libra Ζυγός Libra - Wiktionary http://en.wiktionary.org/wiki/Libra Libra Definition from Wiktionary, the free dictionary See also: libra Contents 1 English 1.1 Etymology 1.2 Pronunciation 1.3 Proper noun 1.3.1 Synonyms 1.3.2 Derived terms 1.3.3 Translations 1.3.4 See also 1.4 Noun 1.4.1 Antonyms 1.4.2 Translations 1.5 See also 1.6 Anagrams 2 Portuguese 2.1 Noun 3 Spanish 3.1 Proper noun English Signs of the Zodiac Virgo Scorpio English Wikipedia has an article about Libra. Etymology From Latin lībra (“scales, balance”). Pronunciation IPA (key): /ˈliːbrə/ Homophone: libre 1 of 3 6/9/2015 7:13 PM Libra - Wiktionary http://en.wiktionary.org/wiki/Libra Audio (US) 0:00 MENU Proper noun Libra 1. (astronomy ): A constellation of the zodiac, supposedly shaped like a set of scales. 2. (astrology ): The astrological sign for the scales, ruled by Venus and covering September 24 - October 23 (tropical astrology) or October 16 - November 16 (sidereal astrology). Synonyms ♎ Derived terms Libran Librae Translations constellation [show ▼] astrological sign [show ▼] See also Zubenelgenubi Zubeneschamali Noun Libra ( plural Libras ) 1. Someone with a Libra star sign Antonyms Aries Translations Someone with a Libra star sign [show ▼] See also 2 of 3 6/9/2015 7:13 PM Libra - Wiktionary http://en.wiktionary.org/wiki/Libra (Western astrology signs ) Western astrology sign ; Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra , Scorpio, Sagittarius, Capricorn, Aquarius, Pisces (Category: en:Astrology) Anagrams Arbil brail Portuguese Noun Libra f 1. -
Publications Year: 2005 1. Apostolovska, G., Ivanova, V
Publications year: 2005 1. Apostolovska, G., Ivanova, V., Borisov, G., Bilkina B., CCD of Asteroids at Rozhen National Astronomical Observatory from 2001 to 2003, 2005, Aerospace Research in Bulgaria, 20, 314-322 2. Apostolovska, G. Bilkina, B., Observations of the Comet Machholz 2004 Q2, MPC 53603- 53604, 24 Feb. 2005. 3. Bachev, R., Strigachev, A., Semkov, E., Short-term optical variability of high-redshift QSO's, 2005, MNRAS, 358, 774-780 4. Bode, M., Zamanov, R., Marchant, J., O'Brien, T. J., V2361 Cygni, 2005, IAUC, .No. 8511 5. Budding, E., Bakis, V., Erdem, A., Demircan, O., Iliev, L., Iliev, I., Slee, O. B., Multi-Facility Study of the Algol-Type Binary Delta Librae, 2005, Ap&SS, 296, 371-389 6. van Cauteren, P., Lampens, P., Robertson, C. W., Strigachev, A., Search for intrinsic variable stars in three open clusters: NGC 1664, NGC 6811, NGC 7209, 2005, Co. Ast., 146, 21-32 7. Dechev, M., Duchlev, P., Koleva, K., Kokotanekova, J., Petrov, N., Publ. Astron. Soc. R. Bo? kovi?, 2005, 5, 145-152 8. Dechev, M., Duchlev, P. Koleva, K. Petrov, N., Helical internal structures in eruptive prominences, 2005, Aerospace Research in Bulgaria, 20 245-252 9. Dimitrov, D. P., Panov, K. P., The flare activity of YZ CMi in 1999 – 2004, 2005, Aerospace Research in Bulgaria, 20, 214-217 10. Dimitrov, D. P., Panov, K. P., Long-term photometric investigation of FK Com, 2005, Aerospace Research in Bulgaria, 20, 218-223 11. Djurasevic, G. Dimitrov, D., Arbutina, B. Albayrak, B., Selam, S. O., A study of close binary system EE Cet, 2005, Mem Soc. -
Astronomy with the Naked Eye a New Geography of the Heavens With
A N EW G EOG R AP H Y OF TH E H EAV EN S W I T H D ESCR IPTIO N S A N D CH A R TS O l’ CONbTELLA TlONS. STARS. AN D PLA N ETS BY R R E P S E R V I SS G A T T . / 8 8 4 7 NEW Y ORK AND DONDON M C M V I I ! RRE P. s s av x ss g GA TT , 1 . 0 mm 33. 1 907 CONTENTS FIIE PLEASURE OF KNOWI NG TH E CONSTELLATI ONS — ’ the sta rs as lan dma rks Eflect of going north or south on the a p — — pearan ce of the hea vens Personal in fluen ce of the s ta rs View — ing the cons tella tion. a mid hi storic scenes Cass iopeia seen fro m ’ — Clytemnestra s tomb The celestia l pagea nt fro mMount Etna — — The sta rs ann ounce the seas ons Atmos pheric influence on — t he a ppea rance of the s ta rs Indi v idua lity of the stars 4 ta r — — — magn itudes Sta r colors The c ha rmof s ta r gro u pings The — h a rmony of the spheres How scientific astronomy has drifted Page 1 NSTELLATIONS ON TH E MERI DI AN I N JAN U ARY — 0! the meridian The dou ble revol u tion of the hea ven s — ~ ~ cha rioteer Ca pella a n d its his tory Ca melopa r — — — the Bu ll Aldeba ran The Hyades The Pleia ' of and su er a u the e ad es— n p stition bo t Pl i O on . -
Observational Studies of X-Ray Binary Systems Observational Studies of X-Ray Binary Systems
mmnML mmmm AWD DE» FIOWS INIS-mf—8690 "'•'..'..-. !' ..- -'. .^: C-^;/- V'-^ ^ ^'vV?*f,>4 "' :f ,.?;•• ..f..-XV., . '4*.> • OBSERVATIONAL STUDIES OF X-RAY BINARY SYSTEMS OBSERVATIONAL STUDIES OF X-RAY BINARY SYSTEMS PROPERTIES OF THE NEUTRON STAR AND ITS COMPANION ORBITAL MOTION AND MASS FLOWS ACADEMISCH PROEFSCHRIFT ter verkrijging van de graad van doctor in de Wiskunde en Natuurwetenschappen aan de Universiteit van Amsterdam, op gezag van de Rector Magnificus, Dr. D.W. Bresters, hoogleraar in de Faculteit der Wiskunde en Natuurwetenschappen, in het openbaar te verdedigen in de Aula der Universiteit (tijdelijk in de Lutherse Kerk, ingang Singel 411, hoek Spui) op woensdag 2 februari 1983 te 13:30 uur door Michiel Baidur Maximiliaan van der Klis geboren te 's Gravenhage PROMOTOR : Prof. Dr. E.P.J, van den Heuvel CO-REFERENT : Dr. Ir. J.A.H. Bieeker CONTENTS 0. Introduction and summary 7 1. Mass-Flux Induced Orbital-Period Changes In X-Ray Binaries 17 2. Cygnus X-3 2.1 A Change In Light Curve Asymmetry and the Ephemeris of Cygnus X-3 31 2.2 The X-Ray Modulation of Cygnus X-3 34 2.3 The Cycle-to-Cycle Variability of Cygnus X-3 40 3. Mass Transfer and Accretion in Centaurus X-3 and SMC X-l 3.1 The Accretion Picture of Cen X-3 as Inferred from One Month of Continuous X-Ray Observations 55 3.2 Long Term X-Ray Observations of SMC X-l Including a Turn-On 62 4. Pulsation and Orbital Parameters of Centaurus X-3 and Vela X-l 4.1 Characteristics of the Cen X-3 Neutron Star from Correlated Spin-Up and X-Ray Luminosity Measurements 69 4.2 The Orbital Parameters and the X-Ray Pulsation of Vela X-l (4U 0900-40) 76 5.