Variable Star Section Circular
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Is the Universe Expanding?: an Historical and Philosophical Perspective for Cosmologists Starting Anew
Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 6-1996 Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew David A. Vlosak Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Cosmology, Relativity, and Gravity Commons Recommended Citation Vlosak, David A., "Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew" (1996). Master's Theses. 3474. https://scholarworks.wmich.edu/masters_theses/3474 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. IS THEUN IVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STAR TING ANEW by David A Vlasak A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements forthe Degree of Master of Arts Department of Philosophy Western Michigan University Kalamazoo, Michigan June 1996 IS THE UNIVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STARTING ANEW David A Vlasak, M.A. Western Michigan University, 1996 This study addresses the problem of how scientists ought to go about resolving the current crisis in big bang cosmology. Although this problem can be addressed by scientists themselves at the level of their own practice, this study addresses it at the meta level by using the resources offered by philosophy of science. There are two ways to resolve the current crisis. -
Extremely Extended Dust Shells Around Evolved Intermediate Mass Stars: Probing Mass Loss Histories,Thermal Pulses and Stellar Evolution
EXTREMELY EXTENDED DUST SHELLS AROUND EVOLVED INTERMEDIATE MASS STARS: PROBING MASS LOSS HISTORIES,THERMAL PULSES AND STELLAR EVOLUTION A Thesis presented to the Faculty of the Graduate School at the University of Missouri In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy by BASIL MENZI MCHUNU Dr. Angela K. Speck December 2011 The undersigned, appointed by the Dean of the Graduate School, have examined the dissertation entitled: EXTREMELY EXTENDED DUST SHELLS AROUND EVOLVED INTERMEDIATE MASS STARS PROBING MASS LOSS HISTORIES, THERMAL PULSES AND STELLAR EVOLUTION USING FAR-INFRARED IMAGING PHOTOMETRY presented by Basil Menzi Mchunu, a candidate for the degree of Doctor of Philosophy and hereby certify that, in their opinion, it is worthy of acceptance. Dr. Angela K. Speck Dr. Sergei Kopeikin Dr. Adam Helfer Dr. Bahram Mashhoon Dr. Haskell Taub DEDICATION This thesis is dedicated to my family, who raised me to be the man I am today under challenging conditions: my grandfather Baba (Samuel Mpala Mchunu), my grandmother (Ma Magasa, Nonhlekiso Mchunu), my aunt Thembeni, and my mother, Nombso Betty Mchunu. I would especially like to thank my mother for all the courage she gave me, bringing me chocolate during my undergraduate days to show her love when she had little else to give, and giving her unending support when I was so far away from home in graduate school. She passed away, when I was so close to graduation. To her, I say, ′′Ulale kahle Macingwane.′′ I have done it with the help from your spirit and courage. I would also like to thank my wife, Heather Shawver, and our beautiful children, Rosemary and Brianna , for making me see life with a new meaning of hope and prosperity. -
The Maunder Minimum and the Variable Sun-Earth Connection
The Maunder Minimum and the Variable Sun-Earth Connection (Front illustration: the Sun without spots, July 27, 1954) By Willie Wei-Hock Soon and Steven H. Yaskell To Soon Gim-Chuan, Chua Chiew-See, Pham Than (Lien+Van’s mother) and Ulla and Anna In Memory of Miriam Fuchs (baba Gil’s mother)---W.H.S. In Memory of Andrew Hoff---S.H.Y. To interrupt His Yellow Plan The Sun does not allow Caprices of the Atmosphere – And even when the Snow Heaves Balls of Specks, like Vicious Boy Directly in His Eye – Does not so much as turn His Head Busy with Majesty – ‘Tis His to stimulate the Earth And magnetize the Sea - And bind Astronomy, in place, Yet Any passing by Would deem Ourselves – the busier As the Minutest Bee That rides – emits a Thunder – A Bomb – to justify Emily Dickinson (poem 224. c. 1862) Since people are by nature poorly equipped to register any but short-term changes, it is not surprising that we fail to notice slower changes in either climate or the sun. John A. Eddy, The New Solar Physics (1977-78) Foreword By E. N. Parker In this time of global warming we are impelled by both the anticipated dire consequences and by scientific curiosity to investigate the factors that drive the climate. Climate has fluctuated strongly and abruptly in the past, with ice ages and interglacial warming as the long term extremes. Historical research in the last decades has shown short term climatic transients to be a frequent occurrence, often imposing disastrous hardship on the afflicted human populations. -
The Kinematic Signature of the Galactic Warp in Gaia DR1-I. the Hipparcos Subsample
Astronomy & Astrophysics manuscript no. WarpGaia c ESO 2021 September 26, 2021 The kinematic signature of the Galactic warp in Gaia DR1 I. The Hipparcos sub-sample E. Poggio1; 2, R. Drimmel2, R. L. Smart2; 3, A. Spagna2, and M. G. Lattanzi2 1 Università di Torino, Dipartimento di Fisica, via P. Giuria 1, 10125 Torino, Italy 2 Osservatorio Astrofisico di Torino, Istituto Nazionale di Astrofisica (INAF), Strada Osservatorio 20, 10025 Pino Torinese, Italy 3 School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK ABSTRACT Context. The mechanism responsible for the warp of our Galaxy, as well as its dynamical nature, continues to remain unknown. With the advent of high precision astrometry, new horizons have been opened for detecting the kinematics associated with the warp and constraining possible warp formation scenarios for the Milky Way. Aims. The aim of this contribution is to establish whether the first Gaia data release (DR1) shows significant evidence of the kinematic signature expected from a long-lived Galactic warp in the kinematics of distant OB stars. As the first paper in a series, we present our approach for analyzing the proper motions and apply it to the sub-sample of Hipparcos stars. Methods. We select a sample of 989 distant spectroscopically-identified OB stars from the New Reduction of Hipparcos (van Leeuwen 2008), of which 758 are also in the first Gaia data release (DR1), covering distances from 0.5 to 3 kpc from the Sun. We develop a model of the spatial distribution and kinematics of the OB stars from which we produce the probability distribution functions of the proper motions, with and without the systematic motions expected from a long-lived warp. -
The Observer's Handbook for 1915
T he O b s e r v e r ’s H a n d b o o k FOR 1915 PUBLISHED BY The Royal Astronomical Society Of Canada E d i t e d b y C . A. CHANT SEVENTH YEAR OF PUBLICATION TORONTO 198 C o l l e g e S t r e e t Pr in t e d f o r t h e S o c ie t y CALENDAR 1915 T he O bserver' s H andbook FOR 1915 PUBLISHED BY The Royal Astronomical Society Of Canada E d i t e d b y C. A. CHANT SEVENTH YEAR OF PUBLICATION TORONTO 198 C o l l e g e S t r e e t Pr in t e d f o r t h e S o c ie t y 1915 CONTENTS Preface - - - - - - 3 Anniversaries and Festivals - - - - - 3 Symbols and Abbreviations - - - - -4 Solar and Sidereal Time - - - - 5 Ephemeris of the Sun - - - - 6 Occultation of Fixed Stars by the Moon - - 8 Times of Sunrise and Sunset - - - - 8 The Sky and Astronomical Phenomena for each Month - 22 Eclipses, etc., of Jupiter’s Satellites - - - - 46 Ephemeris for Physical Observations of the Sun - - 48 Meteors and Shooting Stars - - - - - 50 Elements of the Solar System - - - - 51 Satellites of the Solar System - - - - 52 Eclipses of Sun and Moon in 1915 - - - - 53 List of Double Stars - - - - - 53 List of Variable Stars- - - - - - 55 The Stars, their Magnitude, Velocity, etc. - - - 56 The Constellations - - - - - - 64 Comets of 1914 - - - - - 76 PREFACE The H a n d b o o k for 1915 differs from that for last year chiefly in the omission of the brief review of astronomical pro gress, and the addition of (1) a table of double stars, (2) a table of variable stars, and (3) a table containing 272 stars and 5 nebulae. -
Mar. 10Th, 2016
OAWS #2 Navigating the Night Sky Agenda • 1- It’s Dark! Now What! • 2- It’s Moving All the Time! • 3- What’s That Pattern? • 4- What Do I Need? • 5- Find Me! • 6- Books, Software and Catalogues • 7- Next Challenges It’s Dark! Now What? • As It Gets Dark – Moon, first stars, first planets – It takes between 1 to 2 hours after sunset before it gets dark. – Astronomy night begins when the Sun is 18 degrees below the horizon. – After sunset, planets and bright stars show up within half hour to 1 hour, dimmer stars and bright deep sky objects between 1 hour and 1.5 hours, Milky Way and dimmer deep sky objects after 1.5 hours. It’s Dark! Now What? • Brightest Stars – Sirius, Arcturus, Procyon, Rigel, Betelgeuse, Aldebaran, Capella, Vega, Altair, Antares, Spica, Regulus, Fomalhaut – (demo) • Recognizing Planets – Planets do not twinkle like stars. – Brightest planets: Venus, Jupiter – Other bright planets: Saturn, Mars, Mercury – Planets visible with a telescope: Uranus, Neptune, all minor planets It’s Moving All the Time! • Evening, Midnight, Late Night – Objects rising in the evening will be in the South around midnight and set near sunrise. – Objects in East move towards South then West. – Evening objects in the West will set soon. – Late night objects in the East will rise earlier next month. It’s Moving All the Time! • Sky Movement Throughout the Night – Objects rising in the Southeast will not stay in sky as long as objects rising the Northeast. – Objects rising the in South east will not get very high in the sky. -
Downloads/ Astero2007.Pdf) and by Aerts Et Al (2010)
This work is protected by copyright and other intellectual property rights and duplication or sale of all or part is not permitted, except that material may be duplicated by you for research, private study, criticism/review or educational purposes. Electronic or print copies are for your own personal, non- commercial use and shall not be passed to any other individual. No quotation may be published without proper acknowledgement. For any other use, or to quote extensively from the work, permission must be obtained from the copyright holder/s. i Fundamental Properties of Solar-Type Eclipsing Binary Stars, and Kinematic Biases of Exoplanet Host Stars Richard J. Hutcheon Submitted in accordance with the requirements for the degree of Doctor of Philosophy. Research Institute: School of Environmental and Physical Sciences and Applied Mathematics. University of Keele June 2015 ii iii Abstract This thesis is in three parts: 1) a kinematical study of exoplanet host stars, 2) a study of the detached eclipsing binary V1094 Tau and 3) and observations of other eclipsing binaries. Part I investigates kinematical biases between two methods of detecting exoplanets; the ground based transit and radial velocity methods. Distances of the host stars from each method lie in almost non-overlapping groups. Samples of host stars from each group are selected. They are compared by means of matching comparison samples of stars not known to have exoplanets. The detection methods are found to introduce a negligible bias into the metallicities of the host stars but the ground based transit method introduces a median age bias of about -2 Gyr. -
The First INTEGRAL-OMC Catalogue of Optically Variable Sources
Astronomy & Astrophysics manuscript no. OMC-VAR-catalogue c ESO 2018 August 17, 2018 The first INTEGRAL–OMC catalogue of optically variable sources ? J. Alfonso-Garzon´ 1, A. Domingo1, J.M. Mas-Hesse1, and A. Gimenez´ 2;1 1 Centro de Astrobiolog´ıa – Departamento de Astrof´ısica (CSIC-INTA), POB 78, 28691 Villanueva de la Canada,˜ Spain e-mail: [email protected] 2 European Space Astronomy Centre (ESAC), European Space Agency, POB 78, 28691 Villanueva de la Canada,˜ Spain Received 24 July 2012; accepted 28 September 2012 ABSTRACT Context. The Optical Monitoring Camera (OMC) onboard INTEGRAL provides photometry in the Johnson V-band. With an aperture of 50 mm and a field of view of 5◦×5◦, OMC is able to detect optical sources brighter than V ∼ 18, from a previously selected list of potential targets of interest. After more than nine years of observations, the OMC database contains light curves for more than 70 000 sources (with more than 50 photometric points each). Aims. The objectives of this work have been to characterize the potential variability of the objects monitored by OMC, to identify periodic sources and to compute their periods, taking advantage of the stability and long monitoring time of the OMC. Methods. To detect potential variability, we have performed a chi-squared test, finding 5263 variable sources out of an initial sample of 6071 objects with good photometric quality and more than 300 data points each. We have studied the potential periodicity of these sources using a method based on the phase dispersion minimization technique, optimized to handle light curves with very different shapes. -
GEORGE HERBIG and Early Stellar Evolution
GEORGE HERBIG and Early Stellar Evolution Bo Reipurth Institute for Astronomy Special Publications No. 1 George Herbig in 1960 —————————————————————– GEORGE HERBIG and Early Stellar Evolution —————————————————————– Bo Reipurth Institute for Astronomy University of Hawaii at Manoa 640 North Aohoku Place Hilo, HI 96720 USA . Dedicated to Hannelore Herbig c 2016 by Bo Reipurth Version 1.0 – April 19, 2016 Cover Image: The HH 24 complex in the Lynds 1630 cloud in Orion was discov- ered by Herbig and Kuhi in 1963. This near-infrared HST image shows several collimated Herbig-Haro jets emanating from an embedded multiple system of T Tauri stars. Courtesy Space Telescope Science Institute. This book can be referenced as follows: Reipurth, B. 2016, http://ifa.hawaii.edu/SP1 i FOREWORD I first learned about George Herbig’s work when I was a teenager. I grew up in Denmark in the 1950s, a time when Europe was healing the wounds after the ravages of the Second World War. Already at the age of 7 I had fallen in love with astronomy, but information was very hard to come by in those days, so I scraped together what I could, mainly relying on the local library. At some point I was introduced to the magazine Sky and Telescope, and soon invested my pocket money in a subscription. Every month I would sit at our dining room table with a dictionary and work my way through the latest issue. In one issue I read about Herbig-Haro objects, and I was completely mesmerized that these objects could be signposts of the formation of stars, and I dreamt about some day being able to contribute to this field of study. -
Variable Star
Variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks. Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes Trifid Nebula contains Cepheid variable stars eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11-year solar cycle.[1] Contents Discovery Detecting variability Variable star observations Interpretation of observations Nomenclature Classification Intrinsic variable stars Pulsating variable stars Eruptive variable stars Cataclysmic or explosive variable stars Extrinsic variable stars Rotating variable stars Eclipsing binaries Planetary transits See also References External links Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol.[2][3][4] Of the modern astronomers, the first variable star was identified in 1638 when Johannes Holwarda noticed that Omicron Ceti (later named Mira) pulsated in a cycle taking 11 months; the star had previously been described as a nova by David Fabricius in 1596. This discovery, combined with supernovae observed in 1572 and 1604, proved that the starry sky was not eternally invariable as Aristotle and other ancient philosophers had taught. -
October 2015 BRAS Newsletter
October, 2015 Next Meeting: Monday, Oct. 12th at 7pm at the HRPO Lunar Eclipse on Sept 27th, 2015. Image by BRAS member David Leadingham, one of the few that got a clear view for a couple of minutes through the clouds in our area! Click on the pic for more info on upcoming eclipses What's In This Issue? President's Message AstroShort: Simulating the Universe Secretary's Summary of Sept. Meeting Message From the HRPO Recent BRAS Forum Entries 20/20 Vision Campaign Observing Notes by John Nagle (He's Back!) President's Message “Astronomy is useful because it raises us above ourselves; it is useful because it is grand. It shows us how small is man’s body, how great his mind, since his intelligence can embrace the whole of this dazzling immensity, where his body is only an obscure point, and enjoy its silent harmony." – Henri Poincare, 19th Century mathematician and physicist We all have our reasons for being involved in astronomy. That quote elegantly expresses just one man’s thoughts. What attracted you to astronomy? What do you tell people who ask? I think we all have experienced some indefinable draw to the night sky and the wonders of the universe. Maybe that is it. Wonder. At least for me it is. Wonder, beauty, harmony, perspective. Where does it end? Think about those things and let me know if you have something about that you would like to say at our next meeting. Alternately, you could write up something for this newsletter. Well the total lunar eclipse certainly was a washout. -
Chapter 5 Misaligned Spin Axes in the DI Herculis System
Stars and planets at high spatial and spectral resolution Albrecht, S. Citation Albrecht, S. (2008, December 17). Stars and planets at high spatial and spectral resolution. Retrieved from https://hdl.handle.net/1887/13359 Version: Corrected Publisher’s Version Licence agreement concerning inclusion of doctoral thesis in the License: Institutional Repository of the University of Leiden Downloaded from: https://hdl.handle.net/1887/13359 Note: To cite this publication please use the final published version (if applicable). Chapter 5 Misaligned spin axes in the DI Herculis system DI Herculis is one of the most interesting young eclipsing binary systems known. Its apsidal motion, the rotation of the orbit in its own plane, has been measured to be significantly lower (2.9 × 10−4 ± 0.4 · 10−4 ◦/cycle) than the expected value (1.25 · 10−3 ◦/cycle). Until now the reason why its apsidal motion is much slower than theoretically expected escapes a solid explanation. A number of theories have been put forward to explain this apparent discrepancy, including a revision of general relativity. However the underlying calculations are based on the premise of co-aligned stellar rotation axes. To test this assumption we observed the DI Herculis system during both primary and secondary eclipse with the high resolution Echelle spectrograph Sophie of the Oberserva- torie de Haute Provence. Using our newly developed analysis tools (Chapter 4) we find a strong misalignment be- tween the projections of the stellar spin axes and the orbital spin axis on the sky. The angle between, the projected stellar spin axes and the projected orbital spin axis is (71 ± 4◦) for the primary and (93 ± 8◦) for the secondary.