Program for Monday “Primaries, Secondaries and Population Studies” Talks
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High and Low States of the System AM Herculis
A&A 481, 433–439 (2008) Astronomy DOI: 10.1051/0004-6361:20078556 & c ESO 2008 Astrophysics High and low states of the system AM Herculis K. Wu1,2 andL.L.Kiss2 1 Mullard Space Science Laboratory, University College London, Holmbury St Mary, Surrey RH5 6NT, UK e-mail: [email protected] 2 School of Physics A28, University of Sydney, NSW 2006, Australia e-mail: [email protected] Received 27 August 2007 / Accepted 24 October 2007 ABSTRACT Context. We investigate the distribution of optically high and low states of the system AM Herculis (AM Her). Aims. We determine the state duty cycles, and their relationships with the mass transfer process and binary orbital evolution of the system. Methods. We make use of the photographic plate archive of the Harvard College Observatory between 1890 and 1953 and visual observations collected by the American Association of Variable Star Observers between 1978 and 2005. We determine the statistical probability of the two states, their distribution and recurrence behaviors. Results. We find that the fractional high state duty cycle of the system AM Her is 63%. The data show no preference of timescales on which high or low states occur. However, there appears to be a pattern of long and short duty cycle alternation, suggesting that the state transitions retain memories. We assess models for the high/low states for polars (AM Her type systems). We propose that the white-dwarf magnetic field plays a key role in regulating the mass transfer rate and hence the high/low brightness states, due to variations in the magnetic-field configuration in the system. -
White Dwarfs and Electron Degeneracy
White Dwarfs and Electron Degeneracy Farley V. Ferrante Southern Methodist University Sirius A and B 27 March 2017 SMU PHYSICS 1 Outline • Stellar astrophysics • White dwarfs • Dwarf novae • Classical novae • Supernovae • Neutron stars 27 March 2017 SMU PHYSICS 2 27 March 2017 SMU PHYSICS 3 Pogson’s ratio: 5 100≈ 2.512 27 March 2017 M.S. Physics Thesis Presentation 4 Distance Modulus mM−=5 log10 ( d) − 1 • Absolute magnitude (M) • Apparent magnitude of an object at a standard luminosity distance of exactly 10.0 parsecs (~32.6 ly) from the observer on Earth • Allows true luminosity of astronomical objects to be compared without regard to their distances • Unit: parsec (pc) • Distance at which 1 AU subtends an angle of 1″ • 1 AU = 149 597 870 700 m (≈1.50 x 108 km) • 1 pc ≈ 3.26 ly • 1 pc ≈ 206 265 AU 27 March 2017 SMU PHYSICS 5 Stellar Astrophysics • Stefan-Boltzmann Law: 54 2π k − − −− FT=σσ4; = = 5.67x 10 5 ergs 1 cm 24 K bol 15ch23 • Effective temperature of a star: Temp. of a black body with the same luminosity per surface area • Stars can be treated as black body radiators to a good approximation • Effective surface temperature can be obtained from the B-V color index with the Ballesteros equation: 11 T = 4600+ 0.92(BV−+) 1.70 0.92(BV −+) 0.62 • Luminosity: 24 L= 4πσ rT* E 27 March 2017 SMU PHYSICS 6 H-R Diagram 27 March 2017 SMU PHYSICS 8 27 March 2017 SMU PHYSICS 9 White dwarf • Core of solar mass star • Pauli exclusion principle: Electron degeneracy • Degenerate Fermi gas of oxygen and carbon • 1 teaspoon would weigh 5 tons • No energy produced from fusion or gravitational contraction Hot white dwarf NGC 2440. -
136, June 2008
British Astronomical Association VARIABLE STAR SECTION CIRCULAR No 136, June 2008 Contents Group Photograph, AAVSO/BAAVSS meeting ........................ inside front cover From the Director ............................................................................................... 1 Eclipsing Binary News ....................................................................................... 4 Experiments in the use of a DSLR camera for V photometry ............................ 5 Joint Meeting of the AAVSO and the BAAVSS ................................................. 8 Coordinated HST and Ground Campaigns on CVs ............................... 8 Eclipsing Binaries - Observational Challenges .................................................. 9 Peer to Peer Astronomy Education .................................................................. 10 AAVSO Acronyms De-mystified in Fifteen Minutes ...................................... 11 New Results on SW Sextantis Stars and Proposed Observing Campaign ........ 12 A Week in the Life of a Remote Observer ........................................................ 13 Finding Eclipsing Binaries in NSVS Data ......................................................... 13 British Variable Star Associations 1848-1908 .................................................. 14 “Chasing Rainbows” (The European Amateur Spectroscopy Scene) .............. 15 Long Term Monitoring and the Carbon Miras ................................................. 18 Cataclysmic Variables from Large Surveys: A Silent Revolution -
The Inter-Eruption Timescale of Classical Novae from Expansion of the Z Camelopardalis Shell
The Astrophysical Journal, 756:107 (6pp), 2012 September 10 doi:10.1088/0004-637X/756/2/107 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE INTER-ERUPTION TIMESCALE OF CLASSICAL NOVAE FROM EXPANSION OF THE Z CAMELOPARDALIS SHELL Michael M. Shara1,4, Trisha Mizusawa1, David Zurek1,4, Christopher D. Martin2, James D. Neill2, and Mark Seibert3 1 Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA 2 Department of Physics, Math and Astronomy, California Institute of Technology, 1200 East California Boulevard, Mail Code 405-47, Pasadena, CA 91125, USA 3 Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA Received 2012 May 14; accepted 2012 July 9; published 2012 August 21 ABSTRACT The dwarf nova Z Camelopardalis is surrounded by the largest known classical nova shell. This shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts. The current size of the shell, its known distance, and the largest observed nova ejection velocity set a lower limit to the time since Z Cam’s last outburst of 220 years. The radius of the brightest part of Z Cam’s shell is currently ∼880 arcsec. No expansion of the radius of the brightest part of the ejecta was detected, with an upper limit of 0.17 arcsec yr−1. This suggests that the last Z Cam eruption occurred 5000 years ago. -
Proceedings of the 38Th Conference on Variable Stars Research
OPEN EUROPEAN JOURNAL ON VARIABLE STARS November 2007 http://var.astro.cz/oejv ISSN 1801-5964 Variable Star Section of Czech Astronomical Society and Valašské Meziříčí Observatory Proceedings of the 38th Conference on Variable Stars Research Valašské Meziříčí Observatory, Czech Republic, EU 17th – 19th November 2006, Chief editor Luboš Brát Participants of the conference in front of the observatory 1 OPEN EUROPEAN JOURNAL ON VARIABLE STARS November 2007 http://var.astro.cz/oejv ISSN 1801-5964 CONTENT R. HUDEC, Astronomical Plate Archives and Amateur Variable Stars Researchers .............................................. 3 R. HUDEC, V. ŠIMON, The ESA Gaia Mission and Variable Stars .......................................................................... 9 I. KUDZEJ, P. A. DUBOVSKÝ, T. DOROKHOVA, N. DOROKHOV, N. KOSHKIN, Š. PARIMUCHA, A. RYABOV, M. VADILA, First Results of CCD and Photoelectric Photometry on Astronomical Observatory at Kolonica Saddle ................. .............................................................................................................................................................................. 12 R. HUDEC, How Can Amateur Astronomers and Small Observatories Contribute to Recent Astrophysics ....... 18 R. HUDEC, V. ŠIMON, F. MUNZ, J. ŠTROBL, Investigation of Cataclysmic variables and related objects with the INTEGRAL satellite ............................................................................................................................................ 21 V. ŠIMON, C. BARTOLINI, -
Grant Proposals, 1991-1999
Grant Proposals, 1991-1999 Finding aid prepared by Smithsonian Institution Archives Smithsonian Institution Archives Washington, D.C. Contact us at [email protected] Table of Contents Collection Overview ........................................................................................................ 1 Administrative Information .............................................................................................. 1 Descriptive Entry.............................................................................................................. 1 Names and Subjects ...................................................................................................... 1 Container Listing ............................................................................................................. 2 Grant Proposals https://siarchives.si.edu/collections/siris_arc_251859 Collection Overview Repository: Smithsonian Institution Archives, Washington, D.C., [email protected] Title: Grant Proposals Identifier: Accession 99-171 Date: 1991-1999 Extent: 17 cu. ft. (17 record storage boxes) Creator:: Smithsonian Astrophysical Observatory. Contracts and Procurement Office Language: English Administrative Information Prefered Citation Smithsonian Institution Archives, Accession 99-171, Smithsonian Astrophysical Observatory, Contracts and Procurement Office, Grant Proposals Descriptive Entry This accession consists of records documenting Smithsonian Astrophysical Observatory projects and activities. Materials include proposals, correspondence, progress -
Annual Report 2016–2017 AAVSO
AAVSO The American Association of Variable Star Observers Annual Report 2016–2017 AAVSO Annual Report 2012 –2013 The American Association of Variable Star Observers AAVSO Annual Report 2016–2017 The American Association of Variable Star Observers 49 Bay State Road Cambridge, MA 02138-1203 USA Telephone: 617-354-0484 Fax: 617-354-0665 email: [email protected] website: https://www.aavso.org Annual Report Website: https://www.aavso.org/annual-report On the cover... At the 2017 AAVSO Annual Meeting.(clockwise from upper left) Knicole Colon, Koji Mukai, Dennis Conti, Kristine Larsen, Joey Rodriguez; Rachid El Hamri, Andy Block, Jane Glanzer, Erin Aadland, Jamin Welch, Stella Kafka; and (clockwise from upper left) Joey Rodriguez, Knicole Colon, Koji Mukai, Frans-Josef “Josch” Hambsch, Chandler Barnes. Picture credits In additon to images from the AAVSO and its archives, the editors gratefully acknowledge the following for their image contributions: Glenn Chaple, Shawn Dvorak, Mary Glennon, Bill Goff, Barbara Harris, Mario Motta, NASA, Gary Poyner, Msgr. Ronald Royer, the Mary Lea Shane Archives of the Lick Observatory, Chris Stephan, and Wheatley, et al. 2003, MNRAS, 345, 49. Table of Contents 1. About the AAVSO Vision and Mission Statement 1 About the AAVSO 1 What We Do 2 What Are Variable Stars? 3 Why Observe Variable Stars? 3 The AAVSO International Database 4 Observing Variable Stars 6 Services to Astronomy 7 Education and Outreach 9 2. The Year in Review Introduction 11 The 106th AAVSO Spring Membership Meeting, Ontario, California 11 The -
Bibliography from ADS File: Jordan-Stuart.Bib June 27, 2021 1
Bibliography from ADS file: jordan-stuart.bib Tremblay, P. E., Gentile-Fusillo, N., Cummings, J., et al., “White dwarfs in the August 16, 2021 Gaia era”, 2018IAUS..330..317T ADS Gentile Fusillo, N. P., Tremblay, P. E., Jordan, S., et al., “Can magnetic fields suppress convection in the atmosphere of cool white dwarfs? A case study on Gentile Fusillo, N. P., Tremblay, P. E., Cukanovaite, E., et al., “A catalogue of WD2105-820”, 2018MNRAS.473.3693G ADS white dwarfs in Gaia EDR3”, 2021arXiv210607669G ADS Gaia Collaboration, Clementini, G., Eyer, L., et al., “Gaia Data Re- Gaia Collaboration, Brown, A. G. A., Vallenari, A., et al., “Gaia Early Data lease 1. Testing parallaxes with local Cepheids and RR Lyrae stars”, Release 3. Summary of the contents and survey properties (Corrigendum)”, 2017A&A...605A..79G ADS 2021A&A...650C...3G ADS Moitinho, A., Krone-Martins, A., Savietto, H., et al., “Gaia Data Release 1. The Gaia Collaboration, Klioner, S. A., Mignard, F., et al., “Gaia Early archive visualisation service”, 2017A&A...605A..52M ADS Data Release 3. Acceleration of the Solar System from Gaia astrometry”, Kepler, S. O., Pelisoli, I., Jordan, S., et al., “VizieR Online Data Catalog: SDSS 2021A&A...649A...9G ADS magnetic white dwarf stars (Kepler+, 2013)”, 2017yCat..74292934K Gaia Collaboration, Antoja, T., McMillan, P. J., et al., “Gaia Early Data Release ADS 3. The Galactic anticentre”, 2021A&A...649A...8G ADS Gaia Collaboration, van Leeuwen, F., Vallenari, A., et al., “Gaia Data Release Gaia Collaboration, Luri, X., Chemin, L., et al., “Gaia Early Data 1. Open cluster astrometry: performance, limitations, and future prospects”, Release 3. -
Revised Recovery Plan for the Sihek Or Guam Micronesian Kingfisher (Halcyon Cinnamomina Cinnamomina)
DISCLAIMER Recovery plans delineate actions which the best available science indicates are required to recover and protect listed species. Plans are published by the U.S. Fish and Wildlife Service and sometimes prepared with the assistance of recovery teams, contractors, State agencies, and others. Recovery teams serve as independent advisors to the U.S. Fish and Wildlife Service. Recovery plans are reviewed by the public and submitted to additional peer review before they are approved and adopted by the U.S. Fish and Wildlife Service. Objectives will be attained and any necessary funds made available subject to budgetary and other constraints affecting the parties involved, as well as the need to address other priorities. Nothing in this plan should be construed as a commitment or requirement that any Federal agency obligate or pay funds in contravention of the Anti-Deficiency Act, 31 USC 1341, or any other law or regulation. Recovery plans do not necessarily represent the views nor the official positions or approval of any individuals or agencies involved in the plan formulation, other than the U.S. Fish and Wildlife Service. Recovery plans represent the official position of the U.S. Fish and Wildlife Service only after they have been signed as approved by the Regional Director or Director. Approved recovery plans are subject to modification as dictated by new findings, changes in species status, and the completion of recovery actions. Please check for updates or revisions at the website addresses provided below before using this plan. Literature citation of this document should read as follows: U.S. -
August 2008 Newsletter Page 1
ASSA PRETORIA - AUGUST 2008 NEWSLETTER PAGE 1 NEWSLETTER AUGUST 2008 The next meeting of the Pretoria Centre will take place at Christian Brothers College, Pretoria Road, Silverton, Pretoria Date and time Wednesday 27 August at 19h15 Chairperson Percy Jacobs Beginner’s Corner “Astronomy Starter Package” by Percy J & Danie B What’s Up in the Sky? Danie Barnardo ++++++++++ LEG BREAK - Library open +++++++++++++ MAIN TALK “A Lunar Geotechnical GIS* ” by Leon Croukamp The meeting will be followed by tea/coffee and biscuits as usual. The next observing evening will be held on Friday 22 August at the Pretoria Centre Observatory, which is also situated at CBC. Arrive anytime from 18h30 onwards. *A Lunar Geotechnical GIS for future exploration starting with some comments on why we go back to the moon INSIDE THIS NEWSLETTER LAST MONTH’S MEETING.............................................................................................2 LAST MONTH’S OBSERVING EVENING........................................................................4 STAR NOMENCLATURE OR “NOT ALPHA CRUX, ALPHA CRUCIS ...............................5 NEW KIND OF STAR DISCOVERED IN URSA MAJOR ..................................................7 THE CLIFFS OF MERCURY ...........................................................................................8 BUILDING BLOCKS OF LIFE DETECTED IN DISTANT GALAXY....................................8 TWENTY-FIVE OF HUBBLE'S GREATEST HITS............................................................8 THE WHIRLPOOL GALAXY............................................................................................9 -
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. -
The W.A.S.P the Warren Astronomical Society Paper
Vol. 49, no. 1 January, 2018 The W.A.S.P The Warren Astronomical Society Paper President Jeff MacLeod [email protected] The Warren Astronomical Society First Vice President Jonathan Kade [email protected] Second Vice President Joe Tocco [email protected] Founded: 1961 Treasurer Ruth Huellmantel [email protected] P.O. Box 1505 Secretary Parker Huellmantel [email protected] Outreach Diane Hall [email protected] Warren, Michigan 48090-1505 Publications Brian Thieme [email protected] www.warrenastro.org Entire board [email protected] Astronomy at the Beach Class of 2017 / Photo credit: Phyllis Voorheis 2017 Warren Astronomical Society Banquet The Warren Astronomical Society concluded the year with a bang-up finale, accompanied by an impromptu drum line. Booming drums aside, it was a delight to see new faces in the group. Plus, Jeff MacLeod managed to work in a bit of juggling. The prize table, once again, had a desirable selection of prizes, a choice one being a Vixen telescope which went to our president-elect, Jeff MacLeod. The way he clutched it, you could almost hear him whispering, “My Precious.” Many thanks to the product sponsors for the event: Apache-Sitgreaves Research Center, Celestron Corporation, Oberwerk Corporation, Sirius Astro Products, and Sky and Telescope Magazine, along with the many generous donations from our own members. Continued pg 3 1 Society Meeting Times January Discussion Astronomy presentations and lectures twice Group Meeting each month at 7:30 PM: Tuesday, January 23 from 6:30 - 8:30 PM First Monday at Cranbrook Institute of 22275 Michigan Ave. Science. Dearborn, Michigan Third Thursday at Macomb Community Coffee and cookies provided (donations College - South Campus Building J (Library) requested), bring snacks and drinks to share.