V1309 Scorpii: Merger of a Contact Binary⋆⋆⋆
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White Dwarf Compact Binary Model for Long Gamma-Ray Bursts
MNRAS 000, 1–5 (0000) Preprint 6 October 2018 Compiled using MNRAS LATEX style file v3.0 A Black Hole - White Dwarf Compact Binary Model for Long Gamma-ray Bursts without Supernova Association Yi-Ze Dong, Wei-Min Gu ⋆, Tong Liu, and Junfeng Wang Department of Astronomy, Xiamen University, Xiamen, Fujian 361005, China 6 October 2018 ABSTRACT Gamma-ray bursts (GRBs) are luminous and violent phenomena in the universe. Tra- ditionally, long GRBs are expected to be produced by the collapse of massive stars and associated with supernovae. However, some low-redshift long GRBs have no detection of supernova association, such as GRBs 060505, 060614 and 111005A. It is hard to classify these events convincingly according to usual classifications, and the lack of the supernova implies a non-massive star origin. We propose a new path to produce long GRBs without supernova association, the unstable and extremely violent accretion in a contact binary system consisting of a stellar-mass black hole and a white dwarf, which fills an important gap in compact binary evolution. Key words: accretion, accretion discs – stars: black holes – binaries: close gamma-ray burst: general – white dwarfs 1 INTRODUCTION X-ray binaries (UCXBs) (Nelemans & Jonker 2010) and the repeating fast radio burst (FRB 121102) (Gu et al. 2016). It is generally believed that long gamma-ray bursts (GRBs) In addition, the gravitational wave emission originating originate from the collapse of massive stars and are accom- from the merger of double BHs was detected by LIGO panied with supernovae (Woosley 1993; Woosley & Bloom (Abbott et al. 2016a,b). -
Variable Star Section Circular No
The British Astronomical Association Variable Star Section Circular No. 176 June 2018 Office: Burlington House, Piccadilly, London W1J 0DU Contents Joint BAA-AAVSO meeting 3 From the Director 4 V392 Per (Nova Per 2018) - Gary Poyner & Robin Leadbeater 7 High-Cadence measurements of the symbiotic star V648 Car using a CMOS camera - Steve Fleming, Terry Moon and David Hoxley 9 Analysis of two semi-regular variables in Draco – Shaun Albrighton 13 V720 Cas and its close companions – David Boyd 16 Introduction to AstroImageJ photometry software – Richard Lee 20 Project Melvyn, May 2018 update – Alex Pratt 25 Eclipsing Binary news – Des Loughney 27 Summer Eclipsing Binaries – Christopher Lloyd 29 68u Herculis – David Conner 36 The BAAVSS Eclipsing Binary Programme lists – Christopher Lloyd 39 Section Publications 42 Contributing to the VSSC 42 Section Officers 43 Cover image V392 Per (Nova Per 2018) May 6.129UT iTelescope T11 120s. Martin Mobberley 2 Back to contents Joint BAA/AAVSO Meeting on Variable Stars Warwick University Saturday 7th & Sunday 8th July 2018 Following the last very successful joint meeting between the BAAVSS and the AAVSO at Cambridge in 2008, we are holding another joint meeting at Warwick University in the UK on 7-8 July 2018. This two-day meeting will include talks by Prof Giovanna Tinetti (University College London) Chemical composition of planets in our Galaxy Prof Boris Gaensicke (University of Warwick) Gaia: Transforming Stellar Astronomy Prof Tom Marsh (University of Warwick) AR Scorpii: a remarkable highly variable -
Fundamental Parameters of 4 Massive Eclipsing Binaries in Westerlund 1
Active OB stars: structure, evolution, mass loss and critical limits Proceedings IAU Symposium No. 272, 2010 c 2010 International Astronomical Union C. Neiner, G. Wade, G. Meynet & G. Peters DOI: 00.0000/X000000000000000X Fundamental Parameters of 4 Massive Eclipsing Binaries in Westerlund 1 E. Koumpia and A.Z. Bonanos † National Observatory of Athens, Institute of Astronomy & Astrophysics, I. Metaxa & Vas. Pavlou St., Palaia Penteli GR-15236 Athens, Greece [email protected], [email protected] Abstract. Westerlund 1 is one of the most massive young clusters known in the Local Group, with an age of 3-5 Myr. It contains an assortment of rare evolved massive stars, such as blue, yellow and red supergiants, Wolf-Rayet stars, a luminous blue variable, and a magnetar, as well as 4 massive eclipsing binary systems (Wddeb, Wd13, Wd36, WR77o, see Bonanos 2007). The eclipsing binaries present a rare opportunity to constrain evolutionary models of massive stars, the distance to the cluster and furthermore, to determine a dynamical lower limit for the mass of a magnetar progenitor. Wddeb, being a detached system, is of great interest as it allows determination of the masses of 2 of the most massive unevolved stars in the cluster. We have analyzed spectra of all 4 eclipsing binaries, taken in 2007-2008 with the 6.5 meter Magellan telescope at Las Campanas Observatory, Chile, and present fundamental parameters (masses, radii) for their component stars. Keywords. open clusters and associations: individual (Westerlund 1), stars: fundamental pa- rameters, stars: early-type, binaries: eclipsing, stars: Wolf-Rayet 1. Introduction Westerlund 1 (Wd1) is one of the most massive compact young star clusters known in the Local Group. -
METEOR CSILLAGÁSZATI ÉVKÖNYV 2019 Meteor Csillagászati Évkönyv 2019
METEOR CSILLAGÁSZATI ÉVKÖNYV 2019 meteor csillagászati évkönyv 2019 Szerkesztette: Benkő József Mizser Attila Magyar Csillagászati Egyesület www.mcse.hu Budapest, 2018 Az évkönyv kalendárium részének összeállításában közreműködött: Tartalom Bagó Balázs Görgei Zoltán Kaposvári Zoltán Kiss Áron Keve Kovács József Bevezető ....................................................................................................... 7 Molnár Péter Sánta Gábor Kalendárium .............................................................................................. 13 Sárneczky Krisztián Szabadi Péter Cikkek Szabó Sándor Szőllősi Attila Zsoldos Endre: 100 éves a Nemzetközi Csillagászati Unió ........................191 Zsoldos Endre Maria Lugaro – Kereszturi Ákos: Elemkeletkezés a csillagokban.............. 203 Szabó Róbert: Az OGLE égboltfelmérés 25 éve ........................................218 A kalendárium csillagtérképei az Ursa Minor szoftverrel készültek. www.ursaminor.hu Beszámolók Mizser Attila: A Magyar Csillagászati Egyesület Szakmailag ellenőrizte: 2017. évi tevékenysége .........................................................................242 Szabados László Kiss László – Szabó Róbert: Az MTA CSFK Csillagászati Intézetének 2017. évi tevékenysége .........................................................................248 Petrovay Kristóf: Az ELTE Csillagászati Tanszékének működése 2017-ben ............................................................................ 262 Szabó M. Gyula: Az ELTE Gothard Asztrofi zikai Obszervatórium -
Stsci Newsletter: 2011 Volume 028 Issue 02
National Aeronautics and Space Administration Interacting Galaxies UGC 1810 and UGC 1813 Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) 2011 VOL 28 ISSUE 02 NEWSLETTER Space Telescope Science Institute We received a total of 1,007 proposals, after accounting for duplications Hubble Cycle 19 and withdrawals. Review process Proposal Selection Members of the international astronomical community review Hubble propos- als. Grouped in panels organized by science category, each panel has one or more “mirror” panels to enable transfer of proposals in order to avoid conflicts. In Cycle 19, the panels were divided into the categories of Planets, Stars, Stellar Rachel Somerville, [email protected], Claus Leitherer, [email protected], & Brett Populations and Interstellar Medium (ISM), Galaxies, Active Galactic Nuclei and Blacker, [email protected] the Inter-Galactic Medium (AGN/IGM), and Cosmology, for a total of 14 panels. One of these panels reviewed Regular Guest Observer, Archival, Theory, and Chronology SNAP proposals. The panel chairs also serve as members of the Time Allocation Committee hen the Cycle 19 Call for Proposals was released in December 2010, (TAC), which reviews Large and Archival Legacy proposals. In addition, there Hubble had already seen a full cycle of operation with the newly are three at-large TAC members, whose broad expertise allows them to review installed and repaired instruments calibrated and characterized. W proposals as needed, and to advise panels if the panelists feel they do not have The Advanced Camera for Surveys (ACS), Cosmic Origins Spectrograph (COS), the expertise to review a certain proposal. Fine Guidance Sensor (FGS), Space Telescope Imaging Spectrograph (STIS), and The process of selecting the panelists begins with the selection of the TAC Chair, Wide Field Camera 3 (WFC3) were all close to nominal operation and were avail- about six months prior to the proposal deadline. -
International Astronomical Union Commission 42 BIBLIOGRAPHY of CLOSE BINARIES No. 93
International Astronomical Union Commission 42 BIBLIOGRAPHY OF CLOSE BINARIES No. 93 Editor-in-Chief: C.D. Scarfe Editors: H. Drechsel D.R. Faulkner E. Kilpio E. Lapasset Y. Nakamura P.G. Niarchos R.G. Samec E. Tamajo W. Van Hamme M. Wolf Material published by September 15, 2011 BCB issues are available via URL: http://www.konkoly.hu/IAUC42/bcb.html, http://www.sternwarte.uni-erlangen.de/pub/bcb or http://www.astro.uvic.ca/∼robb/bcb/comm42bcb.html The bibliographical entries for Individual Stars and Collections of Data, as well as a few General entries, are categorized according to the following coding scheme. Data from archives or databases, or previously published, are identified with an asterisk. The observation codes in the first four groups may be followed by one of the following wavelength codes. g. γ-ray. i. infrared. m. microwave. o. optical r. radio u. ultraviolet x. x-ray 1. Photometric data a. CCD b. Photoelectric c. Photographic d. Visual 2. Spectroscopic data a. Radial velocities b. Spectral classification c. Line identification d. Spectrophotometry 3. Polarimetry a. Broad-band b. Spectropolarimetry 4. Astrometry a. Positions and proper motions b. Relative positions only c. Interferometry 5. Derived results a. Times of minima b. New or improved ephemeris, period variations c. Parameters derivable from light curves d. Elements derivable from velocity curves e. Absolute dimensions, masses f. Apsidal motion and structure constants g. Physical properties of stellar atmospheres h. Chemical abundances i. Accretion disks and accretion phenomena j. Mass loss and mass exchange k. Rotational velocities 6. Catalogues, discoveries, charts a. -
Photometric Analysis of Two Extreme Low Mass Ratio Contact Binary Systems
Research in Astronomy and Astrophysics manuscript no. (LATEX: RAAPAPER.tex; printed on May 28, 2021; 0:39) Key words: stars: binaries: eclipsing — stars: evolution — stars: low-mass — techniques: photometric Photometric analysis of two extreme low mass ratio contact binary systems Surjit S Wadhwa1, Nick F H Tothill1, Ain Y DeHorta1, Miroslav Filipovic´1 School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia [email protected] Received 20XX Month Day; accepted 20XX Month Day Abstract Multi band photometry and light curve analysis for two newly recognized con- tact binary systems, TYC 6995-813-1 and NSVS 13602901 are presented. Both were found to be of extreme low mass ratios 0.11 and 0.17, respectively. The secondary components of both systems show evidence of considerable evolution with elevated densities as well as both luminosity and radii well above their main sequence counterparts. Even in the absence of significant spot activity at least one of the systems, TYC 6995-813-1, shows features of magnetic and chromospheric activity. TYC 6995-813-1 is also determined to be a potential merger candidate with its current separation near the theoretical instability separation. 1 INTRODUCTION The merger of contact binary star components are thought to result in a transient event referred to as a red nova. Estimates suggest that up to 1 in 500 stars in the Galaxy maybe contact binaries (Rucinski 2007). The merger event is relatively rare and until recently there had been no confirmed observed events. The initial eruption of V1309 Scorpii (V1309 Sco) (Nakano et al. -
What Can Make a Contact Binary Star Explode? Evan Cook, Kenton Greene, and Prof
What Can Make a Contact Binary Star Explode? Evan Cook, Kenton Greene, and Prof. Larry Molnar, Calvin College, Grand Rapids, Michigan, Summer 2017 Supported by the Dragt Family (EC), a VanderPlas Fellowship (KG), and the National Science Foundation (LM) Introduction Merger Mechanism What To Look For Contact binary stars orbit each other so closely that they share a common Fillout Factor: atmosphere. For millions of years, these stars orbit without significant change. L2 The degree of contact in Eventually, an as yet unknown mechanism causes them to spiral together, merge, a contact binary is called and explode. the fillout factor (Fig. 3). At the upper extreme, Three years ago, we identified a contact binary system, KIC 9832227, which we the surface approaches observe to be spiraling inwards, and which we now predict will explode in the year L (on the left in Fig. 3), 2022, give or take a year. This was the first ever prediction of a nova outburst. We 2 the point at which the are using this opportunity to try to discover the mechanism behind stellar outward centrifugal mergers. To explore this question this summer, we studied our system more Fig. 3. The black line is a cross section through force balances the intensively using both optical and X-ray telescopes. We determined a more the equator of our star. The gray lines show attractive gravitational accurate shape with the PHOEBE software package (see Fig. 1). And we began a the range of possible shapes for contact stars. Fig. 6. A Hubble Space Telescope image force. Material reaching survey of the shapes The fillout factor is a parameter from 0 to 1 of a red nova, V838 Mon, that exploded L flows away from the of other contact Fig. -
Study of Eclipsing Binaries: Light Curves & O-C Diagrams Interpretation
galaxies Review Study of Eclipsing Binaries: Light Curves & O-C Diagrams Interpretation Helen Rovithis-Livaniou Department of Astrophysics, Astronomy & Mechanics, Faculty of Physics, Panepistimiopolis, Zografos, Athens University, 15784 Athens, Greece; [email protected]; Tel.: +30-21-0984-7232 Received: 10 October 2020; Accepted: 6 November 2020; Published: 13 November 2020 Abstract: The continuous improvement in observational methods of eclipsing binaries, EBs, yield more accurate data, while the development of their light curves, that is magnitude versus time, analysis yield more precise results. Even so, and in spite the large number of EBs and the huge amount of observational data obtained mainly by space missions, the ways of getting the appropriate information for their physical parameters etc. is either from their light curves and/or from their period variations via the study of their (O-C) diagrams. The latter express the differences between the observed, O, and the calculated, C, times of minimum light. Thus, old and new light curves analysis methods of EBs to obtain their principal parameters will be considered, with examples mainly from our own observational material, and their subsequent light curves analysis using either old or new methods. Similarly, the orbital period changes of EBs via their (O-C) diagrams are referred to with emphasis on the use of continuous methods for their treatment in absence of sudden or abrupt events. Finally, a general discussion is given concerning these two topics as well as to a few related subjects. Keywords: eclipsing binaries; light curves analysis/synthesis; minima times and (O-C) diagrams 1. Introduction A lot of time has passed since the primitive observations of EBs made with naked eye till today’s space surveys. -
The Massive Wolf-Rayet Binary LSS 1964 (=WR 29) II
A&A 506, 1269–1275 (2009) Astronomy DOI: 10.1051/0004-6361/200810112 & c ESO 2009 Astrophysics The massive Wolf-Rayet binary LSS 1964 (=WR 29) II. The V light curve R. C. Gamen1,2,, E. Fernández-Lajús1,2,†,V.S.Niemela‡, and R. H. Barbá3,4,§ 1 Instituto de Astrofísica de La Plata, CONICET, Paseo del bosque s/n, B1900FWA, La Plata, Argentina 2 Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del bosque s/n, B1900FWA, La Plata, Argentina e-mail: [email protected] 3 Instituto de Ciencias Astronómicas de la Tierra y del Espacio, CONICET, Avda. España 1512 Sur, J5402DSP, San Juan, Argentina 4 Departamento de Física, Universidad de La Serena, Benavente 980, La Serena, Chile Received 2 May 2008 / Accepted 1 August 2009 ABSTRACT Context. WR 29 is a known WN7h+O double-lined binary system with a rather short period (3.164 days). Aims. We search for light variations to determine the inclination of the system and thus the absolute masses of both components. Methods. We observed photometrically the field of WR 29 between December, 2002, and February, 2006. Results. We find that the V light of WR 29 varies in phase with the spectroscopic period of 3.16412 days, presenting two minima corresponding to the conjunctions of the binary components. Numerical models fitted to the light curve indicate an orbital inclination ◦ of about 44 , and masses of 53 M and 42 M for the O- and WN-type components, respectively. Key words. stars: binaries: close – stars: binaries: eclipsing – stars: binaries: spectroscopic – stars: Wolf-Rayet 1. -
Download This Issue (Pdf)
Volume 46 Number 2 JAAVSO 2018 The Journal of the American Association of Variable Star Observers Unmanned Aerial Systems for Variable Star Astronomical Observations The NASA Altair UAV in flight. Also in this issue... • A Study of Pulsation and Fadings in some R CrB Stars • Photometry and Light Curve Modeling of HO Psc and V535 Peg • Singular Spectrum Analysis: S Per and RZ Cas • New Observations, Period and Classification of V552 Cas • Photometry of Fifteen New Variable Sources Discovered by IMSNG Complete table of contents inside... The American Association of Variable Star Observers 49 Bay State Road, Cambridge, MA 02138, USA The Journal of the American Association of Variable Star Observers Editor John R. Percy Laszlo L. Kiss Ulisse Munari Dunlap Institute of Astronomy Konkoly Observatory INAF/Astronomical Observatory and Astrophysics Budapest, Hungary of Padua and University of Toronto Asiago, Italy Toronto, Ontario, Canada Katrien Kolenberg Universities of Antwerp Karen Pollard Associate Editor and of Leuven, Belgium Director, Mt. John Observatory Elizabeth O. Waagen and Harvard-Smithsonian Center University of Canterbury for Astrophysics Christchurch, New Zealand Production Editor Cambridge, Massachusetts Michael Saladyga Nikolaus Vogt Kristine Larsen Universidad de Valparaiso Department of Geological Sciences, Valparaiso, Chile Editorial Board Central Connecticut State Geoffrey C. Clayton University, Louisiana State University New Britain, Connecticut Baton Rouge, Louisiana Vanessa McBride Kosmas Gazeas IAU Office of Astronomy for University of Athens Development; South African Athens, Greece Astronomical Observatory; and University of Cape Town, South Africa The Council of the American Association of Variable Star Observers 2017–2018 Director Stella Kafka President Kristine Larsen Past President Jennifer L. -
Luminous Red Nova Phenomenon
Stars: from Collapse to Collapse ASP Conference Series, Vol. 510 Yu. Yu. Balega, D. O. Kudryavtsev, I. I. Romanyuk, and I. A. Yakunin, eds. c 2017 Astronomical Society of the Pacific Luminous Red Nova Phenomenon E. A. Barsukova 1, V. P. Goranskij 2, and A. F. Valeev 1 1Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhnii Arkhyz, Russia 2Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia Abstract. Luminous red novae form a new type of variable stars which explode turning into cool supergiants. We present a review of the main physical properties of the objects of this class. Most of them are mergers in close binary systems, but some of them may have a di fferent nature. Luminous red novae (LRN) are the stars erupting into cool supergiants (Munari et al. 2002). In other words, they are the stars with cool explosions. Along with the giant eruptions of massive stars, such as the Great eruption of η Car, they form a new class called ILOTs, namely, Intermediate Luminosity Optical Transients. At the outburst maximum, such stars become the brightest in their galaxies, only supernovae exceeded them by luminosity. At maximum, red novae have a definitely red color, K–M spectra of supergiants, evolving to more and more later spectral subclass, and they don’t pass a nebular phase characteristic of classical novae. Great interest to red novae is attracted by the assumption on their origin as a result of merging in close binary systems. In a unique case for the first time, merging process in a contact binary system was observed directly.