Resolving the Nature of RV Tauri Variable Systems Using Unprecedented Observations From
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GALEX Helix Nebula Poster
National Aeronautics and Space Administration The Helix Nebula: What is it? The object shown on the front of this poster is the This “Mountains Helix Nebula. Although this object and others like it are of Creation” image called planetary nebulae (pronounced NEB-u-lee), they was captured by really have nothing to do with planets. They got their name the Spitzer Space ZKHQDVWURQRPHUV¿rst saw them through early telescopes, Telescope in infrared because they looked similar to planets with rings around light. It reveals them, like Saturn. billowing mountains of dust ablaze with A planetary nebula is the ¿res of active star really a shell of glowing gas formation. GALEX and plasma from a star at the can see the new stars end of its life. The star has forming, because they glow brightly in ultraviolet (UV) light. blown off much of its material However, the surrounding dust and gas clouds are cooler and and what is left is a very not so visible to GALEX. compact object called a white dwarf. For a while, the white dwarf is still hot and bright A Tug of War enough to make the material Planetary nebula JnEr1, A star is an amazing from the former star glow, as seen by GALEX. ! Ow! If not for balancing act between two ! * * gravity, my head and that is what we see as a * * would explode! beautiful nebula. Over 10,000 huge forces. On the one * years or so, the gas will drift away and the white dwarf will hand, the crushing force of the star’s own gravity Gravity Heat cool so much that we can no longer see the nebula. -
The Agb Newsletter
THE AGB NEWSLETTER An electronic publication dedicated to Asymptotic Giant Branch stars and related phenomena Official publication of the IAU Working Group on Abundances in Red Giants No. 208 — 1 November 2014 http://www.astro.keele.ac.uk/AGBnews Editors: Jacco van Loon, Ambra Nanni and Albert Zijlstra Editorial Dear Colleagues, It is our pleasure to present you the 208th issue of the AGB Newsletter. The variety of topics is, as usual, enormous, though post-AGB phases feature prominently, as does R Scuti this time. Don’t miss the announcements of the Olivier Chesneau Prize, and of three workshops to keep you busy and entertained over the course of May–July next year. We look forward to receiving your reactions to this month’s Food for Thought (see below)! The next issue is planned to be distributed around the 1st of December. Editorially Yours, Jacco van Loon, Ambra Nanni and Albert Zijlstra Food for Thought This month’s thought-provoking statement is: What is your favourite AGB star, RSG, post-AGB object, post-RSG or PN? And why? Reactions to this statement or suggestions for next month’s statement can be e-mailed to [email protected] (please state whether you wish to remain anonymous) 1 Refereed Journal Papers Evolutionary status of the active star PZ Mon Yu.V. Pakhomov1, N.N. Chugai1, N.I. Bondar2, N.A. Gorynya1,3 and E.A. Semenko4 1Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 119017, Moscow, Russia 2Crimean Astrophysical Observatory, Nauchny, Crimea, 2984009, Russia 3Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetskij prospekt, 13, Moscow 119991, Russia 4Special Astrophysical Observatory of Russian Academy of Sciences, Russia We use original spectra and available photometric data to recover parameters of the stellar atmosphere of PZ Mon, formerly referred as an active red dwarf. -
Poster Abstracts
Aimée Hall • Institute of Astronomy, Cambridge, UK 1 Neptunes in the Noise: Improved Precision in Exoplanet Transit Detection SuperWASP is an established, highly successful ground-based survey that has already discovered over 80 exoplanets around bright stars. It is only with wide-field surveys such as this that we can find planets around the brightest stars, which are best suited for advancing our knowledge of exoplanetary atmospheres. However, complex instrumental systematics have so far limited SuperWASP to primarily finding hot Jupiters around stars fainter than 10th magnitude. By quantifying and accounting for these systematics up front, rather than in the post- processing stage, the photometric noise can be significantly reduced. In this paper, we present our methods and discuss preliminary results from our re-analysis. We show that the improved processing will enable us to find smaller planets around even brighter stars than was previously possible in the SuperWASP data. Such planets could prove invaluable to the community as they would potentially become ideal targets for the studies of exoplanet atmospheres. Alan Jackson • Arizona State University, USA 2 Stop Hitting Yourself: Did Most Terrestrial Impactors Originate from the Terrestrial Planets? Although the asteroid belt is the main source of impactors in the inner solar system today, it contains only 0.0006 Earth mass, or 0.05 Lunar mass. While the asteroid belt would have been much more massive when it formed, it is unlikely to have had greater than 0.5 Lunar mass since the formation of Jupiter and the dissipation of the solar nebula. By comparison, giant impacts onto the terrestrial planets typically release debris equal to several per cent of the planet’s mass. -
Two Rings but No Fellowship: Lotr 1 and Its Relation to Planetary Nebulae
Mon. Not. R. Astron. Soc. 000, 1–16 (2013) Printed 17 October 2018 (MN LATEX style file v2.2) Two rings but no fellowship: LoTr 1 and its relation to planetary nebulae possessing barium central stars. A.A. Tyndall1,2⋆, D. Jones2, H.M.J. Boffin2, B. Miszalski3,4, F. Faedi5, M. Lloyd1, J.A. L´opez6, S. Martell7, D. Pollacco5, and M. Santander-Garc´ıa8 1Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, M13 9PL, UK 2European Southern Observatory, Alonso de C´ordova 3107, Casilla 19001, Santiago, Chile 3South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa 4Southern African Large Telescope. PO Box 9, Observatory 7935, South Africa 5Department of Physics, University of Warwick, CV4 7AL, UK 6Instituto de Astronom´ıa, Universidad Nacional Aut´onoma de M´exico, Ensenada, Baja California, C.P. 22800, Mexico 7Australian Astronomical Observatory, North Ryde, 2109 NSW, Australia 8Observatorio Astron´omico National, Madrid, and Centro de Astrobiolog´ıa, CSIC-INTA, Spain Accepted xxxx xxxxxxxx xx. Received xxxx xxxxxxxx xx; in original form xxxx xxxxxxxx xx ABSTRACT LoTr 1 is a planetary nebula thought to contain an intermediate-period binary central star system ( that is, a system with an orbital period, P, between 100 and, say, 1500 days). The system shows the signature of a K-type, rapidly rotating giant, and most likely constitutes an accretion-induced post-mass transfer system similar to other PNe such as LoTr 5, WeBo 1 and A70. Such systems represent rare opportunities to further the investigation into the formation of barium stars and intermediate period post-AGB systems – a formation process still far from being understood. -
NIR High-Resolution Imaging and Radiative Transfer Modeling of the Frosty Leo Nebula
Planetary Nebulae in our Galaxy and Beyond Proceedings IAU Symposium No. 234, 2006 c 2006 International Astronomical Union M. J. Barlow & R. H. M´endez, eds. doi:10.1017/S1743921306003802 NIR high-resolution imaging and radiative transfer modeling of the Frosty Leo nebula K. Murakawa1, K. Ohnaka1, T. Driebe1, K.-H. Hofmann1, D. Schertl1,S.Oya2, and G. Weigelt1 1Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121 Bonn, Germany email: [email protected] 2Subaru telescope, 650 North A’ohoku Place, Hilo, HI 96720, USA Abstract. We present a K-band speckle image and HK-band polarimetric images of the proto- planetary nebula Frosty Leo obtained using the 6 m SAO telescope and the 8 m Subaru telescope, respectively. Our speckle image revealed clumpy structures in the hourglass-like bipolar nebula. The polarimetric data, for the first time, detected an elongated region with small polarizations and polarization vector alignment on the east side of the central star. We have performed radiative transfer calculations to model the dust shell of Frosty Leo. We found that micron-size grains in the equatorial dense region and small grains in the bipolar lobes are required to explain the total intensity images, the polarization images, and the spectral energy distribution. Keywords. speckle imaging, polarimetry, radiative transfer modeling, Frosty Leo, PPN 1. Introduction Frosty Leo is a well-studied oxygen-rich proto-planetary nebula (PPN). The deep wa- ter ice absorption feature at 3.1 µm(τ3.1µm∼3.3) was detected in the L-band spectrum (Rouan et al. -
The Evolutionary Status of the Frosty Leo Nebula
Asymmetrical Planetary Nebulae II: From Origins to Microstructures ASP Conference Series, Vol. 199, 2000 J.H. Kastner, N. Soker, & S. Rappaport, eds. The evolutionary status of The Frosty Leo Nebula Tyler Bourke1, A. R. Hyland2, Garry Robinson3, & Kevin Luhman1 1Harvard-Smithsonian Center for Astrophysics, Cambridge MA, USA 2Southern Cross University, Lismore NSW, Australia 3University College, UNSW-ADFA, Canberra ACT, Australia Abstract. We present new observational data for IRAS 09371+1212, the Frosty Leo Nebula, in the form of infrared spectra from 2.2–2.5µm which reveal photospheric bands of CO. The 12CO/13CO band ratio deter- mined is similar to those exhibited by evolved K giant stars, and supports the proposal that the object is highly evolved. The equivalent width of the CO bands implies, however, that the spectral type lies in the range G5III to K0III, somewhat earlier than K7III, as derived from colours and optical spectra. The smaller equivalent widths of the CO bands may re- flect a low metal abundance which could fit well with the considerable height of the source above the galactic plane (>0.9kpc). 1. Introduction The Frosty Leo Nebula, IRAS 09371+1212, remains unique with its extremely deep 3.1µm absorption feature, almost two decades in depth, its twin far-infrared emission features at 44 and 62µm, and its abnormal location, >0.9kpc from the plane of the Galaxy. Forveille et al. (1987; hereafter FMOL) concluded, primarily on the basis of its 2.6mm CO emission spectrum, that it is a post-AGB star with a bipolar circumstellar envelope, and suggested water ice mantles around the grains as the source of the excess emission in the 60µm IRAS band. -
Nightwatch Club Events Calendar President's Message
Henry Wadsworth Longfellow Henry Wadsworth Thewithfilled skyby day. is stars, invisible Volume 32 Number 06 nightwatch June 2012 President's Message Club Events Calendar Busy days right now, both in the heavens and here on Earth. June 8 - General Meeting – Speaker Robert Stephens - I've heard lots of good reports of people successfully viewing the “A Journey Through the Asteroid Belt” eclipse on May 20. My own eclipse trip to Page, Arizona, was a June 16 - Star Party - White Mountain smashing success. The lunar eclipse early in the morning on June 22 - Star Party - Cottonwood Springs - joint with June 4 was clouded out, at least here in Claremont. By the time Palm Springs Braille Institute you read this, the transit of Venus across the face of the sun on June 5 will already have happened. I hope you got a chance to July 2 - School Star Party - Colony High School, Ontario see it—it won't happen again until 2117. July 5 - Board Meeting, 6:15 We also have some great club events coming up. Our speaker July 13 - General Meeting for the June 8 general meeting is Robert Stephens July 21 – Star Party – Cottonwood Springs (http://planetarysciences.org/stephens.html), who will give us “A July 24 - Ontario Library Main Branch - Dark to 9pm Journey Through the Asteroid Belt”. On June 16 we'll have a star July 25 – Star Party – Orange County Braille Institute, party at White Mountain. My annual curse has struck again—I'll Anaheim be in New York looking at fossils instead of on White Mountain looking at stars, but I hope you all have fun without me. -
Eagle Nebula Star Formation Region
Eagle Nebula Star Formation Region AST 303: Chapter 17 1 The Formation of Stars (2) • A cloud of gas and dust must collapse if stars are to be formed. • The self-gravity of the cloud will tend to cause it to collapse. • Radiation pressure from nearby hot stars may do the same. • The passage of a shock wave from a nearby supernova blast or some other source (such as galactic shock waves) may do the same. – Note: The “sonic boom” of a jet plane is an example of a shock wave. • When two clouds collide, they may cause each other to collapse. AST 303: Chapter 17 2 Trifid Nebula AST 303: Chapter 17 3 Trifid Nebula Stellar Nursery Revealed AST 303: Chapter 17 4 Young Starburst Cluster Emerges from Cloud AST 303: Chapter 17 5 The Formation of Stars (3) • The gas in the collapsing cloud probably becomes turbulent. • This would tend to fragment the collapsing gas, producing condensations that would be the nuclei of new stars. • There is abundant evidence that shows that the stars in a cluster are all about the same age. For a young cluster, many stars have not yet reached the main sequence: ! Isochron Luminosity "Temperature AST 303: Chapter 17 6 The Formation of Stars (4) • The evolutionary paths of young stars on the H-R diagram look like this. Note the T Tauri stars, long thought to be young stars. • Theory says that these stars use convection as the main method of transporting energy to their surfaces. ! T Tauri Stars Luminosity "Temperature AST 303: Chapter 17 7 The Search for Stellar Precursors • Astronomers have long been fascinated by very dark, dense regions seen outlined against bright gas, called globules. -
The ISO/LWS Spectrum of the Egg Nebula, AFGL 2688 ? ; P
Astron. Astrophys. 315, L265–L268 (1996) ASTRONOMY AND ASTROPHYSICS The ISO/LWS spectrum of the Egg nebula, AFGL 2688 ? ; P. Cox 1 ;8 ,E.Gonz´alez-Alfonso2,M.J.Barlow3,X.-W.Liu3,T.Lim4, B.M. Swinyard5, J. Cernicharo6 2,A.Omont7, E. Caux8,C.Gry4;10, M.J. Griffin9,J.-P.Baluteau10,P.E.Clegg9,S.Sidher4,D.P´equignot11, Nguyen-Q-Rieu12, K.J. King5, P.A.R. Ade9,W.A.Towlson3,R.J.Emery5,I.Furniss3,M.Joubert13, C.J. Skinner14,M.Cohen15,C.Armand4,M.Burgdorf4, D. Eward4, A. Di Giorgio4, S. Molinari4, D. Texier4,N.Trams4,S.J.Unger5,W.M.Glencross3, D. Lorenzetti16, B. Nisini16, R. Orfei16, P. Saraceno16, and G. Serra8 1 Institut d’Astrophysique Spatiale, Bat.^ 120, Universite´ de Paris XI, F-91405 Orsay, France 2 Observatorio Astronomico Nacional. Apartado 1143. E-28800 Alcala de Henares, Spain 3 Dept. of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK 4 The LWS Instrument-Dedicated-Team, ISO Science Operations Centre, P.O. Box 50727, E-28080 Madrid, Spain 5 Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK 6 Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid, Spain 7 Institut d’Astrophysique de Paris, C.N.R.S., 98b bd. Arago, F-75014 Paris, France 8 Centre d’Etude Spatiale des Rayonnements, CESR/CNRS-UPS, BP 4346, F-31029 Toulouse Cedex, France 9 Dept. of Physics, Queen Mary and Westfield College Mile End Road, London E1 4NS, UK 10 Laboratoire d’Astronomie Spatiale, CNRS, BP 8, F-13376 Marseille Cedex 12, France 11 Observatoire de Paris, Section d’Astrophysique, F-92190 Paris, France 12 Observatoire de Paris, 61 avenue de l’Observatoire, F-75014 Paris, France 13 CNES, 2 place Maurice Quentin, F-75001 Paris, France 14 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 15 Radio Astronomy Laboratory, 601 Cambell Hall, University of California, Berkeley, CA 94720, USA 16 CNR-Instituto di Fisica dello Spazio Interplanetario, Casella Postale 27 I-00044 Frascati, Italy Received 15 July 1996 / Accepted 13 September 1996 Abstract. -
Information Bulletin on Variable Stars
COMMISSIONS AND OF THE I A U INFORMATION BULLETIN ON VARIABLE STARS Nos November July EDITORS L SZABADOS K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI ADMINISTRATION Zs KOVARI EDITORIAL BOARD L A BALONA M BREGER E BUDDING M deGROOT E GUINAN D S HALL P HARMANEC M JERZYKIEWICZ K C LEUNG M RODONO N N SAMUS J SMAK C STERKEN Chair H BUDAPEST XI I Box HUNGARY URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN COPYRIGHT NOTICE IBVS is published on b ehalf of the th and nd Commissions of the IAU by the Konkoly Observatory Budap est Hungary Individual issues could b e downloaded for scientic and educational purp oses free of charge Bibliographic information of the recent issues could b e entered to indexing sys tems No IBVS issues may b e stored in a public retrieval system in any form or by any means electronic or otherwise without the prior written p ermission of the publishers Prior written p ermission of the publishers is required for entering IBVS issues to an electronic indexing or bibliographic system to o CONTENTS C STERKEN A JONES B VOS I ZEGELAAR AM van GENDEREN M de GROOT On the Cyclicity of the S Dor Phases in AG Carinae ::::::::::::::::::::::::::::::::::::::::::::::::::: : J BOROVICKA L SAROUNOVA The Period and Lightcurve of NSV ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::: W LILLER AF JONES A New Very Long Period Variable Star in Norma ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: EA KARITSKAYA VP GORANSKIJ Unusual Fading of V Cygni Cyg X in Early November ::::::::::::::::::::::::::::::::::::::: -
Title a Self-Consistent Photoionization-Dust
A self-consistent photoionization-dust continuum-molecular line Title transfer model of NGC 7027 Author(s) Volk, K; Kwok, S Citation The Astrophysical Journal, 1997, v. 477 n. 2 pt. 1, p. 722-731 Issued Date 1997 URL http://hdl.handle.net/10722/179686 Rights Creative Commons: Attribution 3.0 Hong Kong License THE ASTROPHYSICAL JOURNAL, 477:722È731, 1997 March 10 ( 1997. The American Astronomical Society. All rights reserved. Printed in U.S.A. A SELF-CONSISTENT PHOTOIONIZATIONÈDUST CONTINUUMÈMOLECULAR LINE TRANSFER MODEL OF NGC 7027 KEVIN VOLK AND SUN KWOK Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4 Received 1996 June 20; accepted 1996 September 23 ABSTRACT A model to simulate the entire spectrum (1000Ó to 1 cm) of the high-excitation young planetary nebula NGC 7027 is presented. The ionized, dust, and molecular components of the object are modeled using geometric parameters obtained from visible, radio, infrared, and CO data. The physical processes considered include recombination lines of H and He, collisional excited lines of metals, bf and † contin- uum radiations, two-photon radiation, dust continuum radiation, and molecular rotational and vibra- tional transitions. The dust component is assumed to be heated by a combination of direct starlight and the line and continuum radiation from the ionized nebula. The molecular component of the nebula is coupled to the dust component through the stimulated absorption of the dust continuum radiation. Spe- ciÐcally, we compare the predicted Ñuxes of the CO rotational lines and the 179.5 km water rotational line to those observed by the Infrared Space Observatory satellite. -
Variable Star Classification and Light Curves Manual
Variable Star Classification and Light Curves An AAVSO course for the Carolyn Hurless Online Institute for Continuing Education in Astronomy (CHOICE) This is copyrighted material meant only for official enrollees in this online course. Do not share this document with others. Please do not quote from it without prior permission from the AAVSO. Table of Contents Course Description and Requirements for Completion Chapter One- 1. Introduction . What are variable stars? . The first known variable stars 2. Variable Star Names . Constellation names . Greek letters (Bayer letters) . GCVS naming scheme . Other naming conventions . Naming variable star types 3. The Main Types of variability Extrinsic . Eclipsing . Rotating . Microlensing Intrinsic . Pulsating . Eruptive . Cataclysmic . X-Ray 4. The Variability Tree Chapter Two- 1. Rotating Variables . The Sun . BY Dra stars . RS CVn stars . Rotating ellipsoidal variables 2. Eclipsing Variables . EA . EB . EW . EP . Roche Lobes 1 Chapter Three- 1. Pulsating Variables . Classical Cepheids . Type II Cepheids . RV Tau stars . Delta Sct stars . RR Lyr stars . Miras . Semi-regular stars 2. Eruptive Variables . Young Stellar Objects . T Tau stars . FUOrs . EXOrs . UXOrs . UV Cet stars . Gamma Cas stars . S Dor stars . R CrB stars Chapter Four- 1. Cataclysmic Variables . Dwarf Novae . Novae . Recurrent Novae . Magnetic CVs . Symbiotic Variables . Supernovae 2. Other Variables . Gamma-Ray Bursters . Active Galactic Nuclei 2 Course Description and Requirements for Completion This course is an overview of the types of variable stars most commonly observed by AAVSO observers. We discuss the physical processes behind what makes each type variable and how this is demonstrated in their light curves. Variable star names and nomenclature are placed in a historical context to aid in understanding today’s classification scheme.