The Effective Temperature and the Absolute Magnitude of the Stars
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The AAVSO DSLR Observing Manual
The AAVSO DSLR Observing Manual AAVSO 49 Bay State Road Cambridge, MA 02138 email: [email protected] Version 1.2 Copyright 2014 AAVSO Foreword This manual is a basic introduction and guide to using a DSLR camera to make variable star observations. The target audience is first-time beginner to intermediate level DSLR observers, although many advanced observers may find the content contained herein useful. The AAVSO DSLR Observing Manual was inspired by the great interest in DSLR photometry witnessed during the AAVSO’s Citizen Sky program. Consumer-grade imaging devices are rapidly evolving, so we have elected to write this manual to be as general as possible and move the software and camera-specific topics to the AAVSO DSLR forums. If you find an area where this document could use improvement, please let us know. Please send any feedback or suggestions to [email protected]. Most of the content for these chapters was written during the third Citizen Sky workshop during March 22-24, 2013 at the AAVSO. The persons responsible for creation of most of the content in the chapters are: Chapter 1 (Introduction): Colin Littlefield, Paul Norris, Richard (Doc) Kinne, Matthew Templeton Chapter 2 (Equipment overview): Roger Pieri, Rebecca Jackson, Michael Brewster, Matthew Templeton Chapter 3 (Software overview): Mark Blackford, Heinz-Bernd Eggenstein, Martin Connors, Ian Doktor Chapters 4 & 5 (Image acquisition and processing): Robert Buchheim, Donald Collins, Tim Hager, Bob Manske, Matthew Templeton Chapter 6 (Transformation): Brian Kloppenborg, Arne Henden Chapter 7 (Observing program): Des Loughney, Mike Simonsen, Todd Brown Various figures: Paul Valleli Clear skies, and Good Observing! Arne Henden, Director Rebecca Turner, Operations Director Brian Kloppenborg, Editor Matthew Templeton, Science Director Elizabeth Waagen, Senior Technical Assistant American Association of Variable Star Observers Cambridge, Massachusetts June 2014 i Index 1. -
Part V Stellar Spectroscopy
Part V Stellar spectroscopy 53 Chapter 10 Classification of stellar spectra Goal-of-the-Day To classify a sample of stars using a number of temperature-sensitive spectral lines. 10.1 The concept of spectral classification Early in the 19th century, the German physicist Joseph von Fraunhofer observed the solar spectrum and realised that there was a clear pattern of absorption lines superimposed on the continuum. By the end of that century, astronomers were able to examine the spectra of stars in large numbers and realised that stars could be divided into groups according to the general appearance of their spectra. Classification schemes were developed that grouped together stars depending on the prominence of particular spectral lines: hydrogen lines, helium lines and lines of some metallic ions. Astronomers at Harvard Observatory further developed and refined these early classification schemes and spectral types were defined to reflect a smooth change in the strength of representative spectral lines. The order of the spectral classes became O, B, A, F, G, K, and M; even though these letter designations no longer have specific meaning the names are still in use today. Each spectral class is divided into ten sub-classes, so that for instance a B0 star follows an O9 star. This classification scheme was based simply on the appearance of the spectra and the physical reason underlying these properties was not understood until the 1930s. Even though there are some genuine differences in chemical composition between stars, the main property that determines the observed spectrum of a star is its effective temperature. -
Calibration Against Spectral Types and VK Color Subm
Draft version July 19, 2021 Typeset using LATEX default style in AASTeX63 Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration Against Spectral Types and V-K Color Gerard T. van Belle,1 Kaspar von Braun,1 David R. Ciardi,2 Genady Pilyavsky,3 Ryan S. Buckingham,1 Andrew F. Boden,4 Catherine A. Clark,1, 5 Zachary Hartman,1, 6 Gerald van Belle,7 William Bucknew,1 and Gary Cole8, ∗ 1Lowell Observatory 1400 West Mars Hill Road Flagstaff, AZ 86001, USA 2California Institute of Technology, NASA Exoplanet Science Institute Mail Code 100-22 1200 East California Blvd. Pasadena, CA 91125, USA 3Systems & Technology Research 600 West Cummings Park Woburn, MA 01801, USA 4California Institute of Technology Mail Code 11-17 1200 East California Blvd. Pasadena, CA 91125, USA 5Northern Arizona University Department of Astronomy and Planetary Science NAU Box 6010 Flagstaff, Arizona 86011, USA 6Georgia State University Department of Physics and Astronomy P.O. Box 5060 Atlanta, GA 30302, USA 7University of Washington Department of Biostatistics Box 357232 Seattle, WA 98195-7232, USA 8Starphysics Observatory 14280 W. Windriver Lane Reno, NV 89511, USA (Received April 18, 2021; Revised June 23, 2021; Accepted July 15, 2021) Submitted to ApJ ABSTRACT We calculate directly determined values for effective temperature (TEFF) and radius (R) for 191 giant stars based upon high resolution angular size measurements from optical interferometry at the Palomar Testbed Interferometer. Narrow- to wide-band photometry data for the giants are used to establish bolometric fluxes and luminosities through spectral energy distribution fitting, which allow for homogeneously establishing an assessment of spectral type and dereddened V0 − K0 color; these two parameters are used as calibration indices for establishing trends in TEFF and R. -
Thomas J. Maccarone Texas Tech
Thomas J. Maccarone PERSONAL Born August 26, 1974, Haverhill, Massachusetts, USA INFORMATION US Citizen CONTACT Department of Physics & Astronomy Voice: +1-806-742-3778 INFORMATION Texas Tech University Lubbock TX 79409 E-mail: [email protected] RESEARCH Compact object populations, especially in globular clusters; accretion and ejection physics; time INTERESTS series analysis methodology PROFESSIONAL Texas Tech University EXPERIENCE Lubbock, Texas Presidential Research Excellence Professor, Department of Physics & Astronomy August 2018-present Professor, Department of Physics & Astronomy August 2017- August 2018 Associate Professor, Department of Physics January 2013 - August 2017 University of Southampton Southampton, UK Lecturer, then Reader, School of Physics and Astronomy July 2005-December 2012 University of Amsterdam Amsterdam, The Netherlands Postdoctoral researcher May 2003 - June 2005 SISSA (Scuola Internazionale di Studi Avanazti/International School for Advanced Studies) Trieste, Italy Postdoctoral researcher November 2001 - April 2003 Yale University New Haven, Connecticut USA Research Assistant May 1997 - August 2001 Jet Propulsion Laboratory Pasadena, California USA Summer Undergraduate Research Fellow June 1994 - August 1994 EDUCATION Yale University, New Haven, CT USA Department of Astronomy Ph.D., December 2001 Dissertation Title: “Constraints on Black Hole Emission Mechanisms” Advisor: Paolo S. Coppi M.S., M.Phil., Astronomy, May 1999 California Institute of Technology, Pasadena, California USA B.S., Physics, June, 1996 HONORS AND Integrated Scholar, Designation from Texas Tech for faculty who integrate teaching, research and AWARDS service activities together, 2020 Professor of the Year Award, Texas Tech Society of Physics Students, 2017, 2019 Dirk Brouwer Prize from Yale University for “a contribution of unusual merit to any branch of astronomy,” 2003 Harry A. -
University Astronomy: Homework 8
University Astronomy: Homework 8 Alvin Lin January 2019 - May 2019 Question 13.1 What is the apparent magnitude of the Sun as seen from Mercury at perihelion? What is the apparent magnitude of the Sun as seen from Eris at perihelion? p 2 dMercury = dmajor 1 − e = 0:378AU = 1:832 × 10−6pc mSun;mercury = MSun;mercury + 5 log(dMercury) − 5 = −28:855 p 2 dEris = dmajor 1 − e = 67:90AU = 0:00029pc mSun;Eris = MSun;Eris + 5 log(dEris) − 5 = −17:85 Question 13.2 Considering absolute magnitude M, apparent magnitude m, and distance d or par- allax π00, compute the unknown for each of these stars: (a) m = −1:6 mag; d = 4:3 pc. What is M? M = m − 5 log(d) + 5 = 0:232 mag (b) M = 14:3 mag; m = 10:9 mag. what is d? m−M+5 d = 10 5 = 2:089 pc 1 (c) m = 5:6 mag; d = 88 pc. What is M? M = m − 5 log(d) + 5 = 0:877 mag (d) M = −0:9 mag; d = 220 pc. What is m? m = M + 5 log(d) − 5 = 5:81 mag (e) m = 0:2 mag;M = −9:0 mag. What is d? m−M+5 d = 10 5 = 691:8 (f) m = 7:4 mag; π00 = 0:004300. What is M? 1 d = = 232:55 pc π00 M = m − 5 log(d) + 5 = 0:567 mag Question 13.3 What are the angular diameters of the following, as seen from the Earth? 5 (a) The Sun, with radius R = R = 7 × 10 km 5 d = 2R = 14 × 10 km d D ≈ tan−1( ) ≈ 0:009◦ = 193000 θ D (b) Betelgeuse, with MV = −5:5 mag; mV = 0:8 mag;R = 650R d = 2R = 1300R m−M+5 15 D = 10 5 = 181:97 pc = 5:62 × 10 km d D ≈ tan−1( ) ≈ 0:03300 θ D (c) The galaxy M31, with R ≈ 30 kpc at a distance D ≈ 0:7 Mpc d D ≈ tan−1( ) = 4:899◦ = 17636:700 θ D (d) The Coma cluster of galaxies, with R ≈ 3 Mpc at a distance D ≈ 100 Mpc d D ≈ tan−1( ) = 3:43◦ = 12361:100 θ D 2 Question 13.4 The Lyten 726-8 star system contains two stars, one with apparent magnitude m = 12:5 and the other with m = 12:9. -
The Spherical Bolometric Albedo of Planet Mercury
The Spherical Bolometric Albedo of Planet Mercury Anthony Mallama 14012 Lancaster Lane Bowie, MD, 20715, USA [email protected] 2017 March 7 1 Abstract Published reflectance data covering several different wavelength intervals has been combined and analyzed in order to determine the spherical bolometric albedo of Mercury. The resulting value of 0.088 +/- 0.003 spans wavelengths from 0 to 4 μm which includes over 99% of the solar flux. This bolometric result is greater than the value determined between 0.43 and 1.01 μm by Domingue et al. (2011, Planet. Space Sci., 59, 1853-1872). The difference is due to higher reflectivity at wavelengths beyond 1.01 μm. The average effective blackbody temperature of Mercury corresponding to the newly determined albedo is 436.3 K. This temperature takes into account the eccentricity of the planet’s orbit (Méndez and Rivera-Valetín. 2017. ApJL, 837, L1). Key words: Mercury, albedo 2 1. Introduction Reflected sunlight is an important aspect of planetary surface studies and it can be quantified in several ways. Mayorga et al. (2016) give a comprehensive set of definitions which are briefly summarized here. The geometric albedo represents sunlight reflected straight back in the direction from which it came. This geometry is referred to as zero phase angle or opposition. The phase curve is the amount of sunlight reflected as a function of the phase angle. The phase angle is defined as the angle between the Sun and the sensor as measured at the planet. The spherical albedo is the ratio of sunlight reflected in all directions to that which is incident on the body. -
2013 Version
Citizen Science with Variable Stars Brought to you by the AAVSO, Astronomers without Borders, the National Science Foundation and Your Universe Astronomers need your help! Many bright stars change in brightness all the time and for many different reasons. Some stars are too bright for professionals to CitizenSky is a collaboration of the look at with most large telescopes. So, we American Association of need your help to watch these stars as they Variable Star Observers (AAVSO), the University of dim and brighten over the next several years. Denver, the Adler Planetarium, the Johns Hopkins University and the California Academies of This guide will help you find these bright Science with support from the National Science Foundation. stars, measure their brightness and then submit the measurements to assist professional astronomers. Participate in one of the largest and longest running citizen science projects in history! Thousands of people just like you are helping o ut. Astronomers need large numbers of people to get the amount of precision they need to do their research. You are the key. Header artwork is reproduced with permission from Sky & Telescope magazine (www.skyandtelescope.com) Betelgeuse – Alpha Orionis From the city or country sky, from almost any part of the world, the majestic figure of Orion dominates the night sky with his belt, sword, and club. Low and to the right is the great red pulsating supergiant, Betelgeuse (alpha Orionis). Recently acquiring fame for being the first star to have its atmosphere directly imaged (shown below), alpha Orionis has captivated observers' attention for centuries. At minimum brightness, as in 1927 and 1941, its magnitude may drop below 1.2. -
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. -
Reply to the Comment of T. Metcalfe and J. Van Saders on the Science Report ”The Sun Is Less Active Than Other Solar-Like Stars” by T
Reply to the comment of T. Metcalfe and J. van Saders on the Science report "The Sun is less active than other solar-like stars" by T. Reinhold, A. I. Shapiro, S. K. Solanki, B. T. Montet, N. A. Krivova, R. H. Cameron, E. M. Amazo-G´omez Metcalfe & van Saders (1) show that stars in the periodic sample of (2) have on average smaller effective temperatures and slightly higher metallicities than stars in the non-periodic sample. This implies that the periodic stars have systematically smaller Rossby numbers than the non-periodic stars. (1) interpret this as a confirmation of their hypothesis of the evolutionary transition and decoupling between rotation and magnetic activity that stars experience above a critical Rossby number (3, 4). According to their interpretation, the non-periodic stars and the Sun are either currently in transition to a magnetically inactive future or have already completed it, while the periodic stars did not yet start such a transition. We agree with (1) that both the differences in the fundamental parameters, and the existence of the highly active periodic stars can be explained by the transition hypothesis, which was already indicated as a possible explanation of this phenomenon in (2). At the same time, we want to point out that the alternative explanation, that the Sun and other solar-like stars may occasionally experience epochs of high activity, also allows explaining the available data. In the original study, (2) showed the variability distribution of stars with temperatures between 5500{6000 K and metallicities from -0.8 dex to 0.3 dex. -
ATNF News Issue No
ATNF News Issue No. 66, April 2009 ISSN 1323-6326 See Compact Array Broadband Backend (CABB) article on page 6. Left to right: CABB Project Leader Dr Warwick Wilson, CSIRO Chief Executive Offi cer Megan Clark and ATNF Acting Director Dr Lewis Ball, with a CABB signal processing board in front of two antennas of the Australia Telescope Compact Array. Photo: Paul Mathews Photographics Removing the “spaghetti” of ribbon cable that fed the old correlator, from left to right, Matt Shields (obscured), Brett Hiscock, Scott Munting, Mark Leach, and Peter Mirtschin. Photo: CSIRO Cover page images CABB Project—team photo. Back row, left to right: Warwick Wilson (Project Leader), Paul Roberts, Grant Hampson, Peter Axtens, Yoon Chung. Middle row: Aaron Sanders, Dick Ferris (Project Engineer), Matt Shields, Mark Leach (Project Manager). Front row: Troy Elton, Andrew Brown, Raji Chekkala, Evan Davis. Other contributors (not in photo): Scott Saunders. (See article on page 6.) Photo: Tim Wheeler, April 2009 The Sunrise television crew prepare to broadcast live from the grounds of the CSIRO Parkes Observatory. Photo: Tim Ruckley, CSIRO Installation of a 300 – 900-MHz receiver on the Parkes 64-m radio telescope. (See article on page 28.) Photo: Maik Wolleben, CSIRO 2 ATNF News, Issue 66, April 2009 Contents Editorial.............................................................................................................................................................................3 From the Director ......................................................................................................................................................4 -
University Microfilms International 300 N
INFORMATION TO USERS This was produced from a copy of a document sent to us for microfilming. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help you understand markings or notations which may appear on this reproduction. 1. The sign or "target” for pages apparently lacking from the document photographed is “ Missing Page(s)”. If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure you of complete continuity. 2. When an image on the film is obliterated with a round black mark it is an indication that the film inspector noticed either blurred copy because of movement during exposure, or duplicate copy. Unless we meant to delete copyrighted materials that should not have been filmed, you will find a good image o f the page in the adjacent frame. If copyrighted materials were deleted you will find a target note listing the pages in the adjacent frame. 3. When a map, drawing or chart, etc., is part of the material being photo graphed the photographer has followed a definite method in “sectioning” the material. It is customary to begin filming at the upper left hand corner of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete. -
Newsletter 2021-2 April 2021
Newsletter 2021-2 April 2021 www.variablestarssouth.org A seemingly compelling sinusoidal fit to an O - C diagram for GZ Pup that may indicate a third body in the system. But all is not as it seems. Read on page 13 how Tom Richards, with the help of Jeff Byron, shows why this scenario just isn’t true. Contents From the Director - Mark Blackford .......................................................................................................................................................2 RASNZ Annual Conference – Steve Butler ...............................................................................................................................3 Identifications for five old variables – Mati Morel ..............................................................................................................4 The effects of master flats on the accuracy of DSLR photometry – Roy Axelsen ...........6 Refining the orbital period of KX Velorum – Mark Blackford ...........................................................................9 The cycle count error trap – Tom Richards ...........................................................................................................................14 Publication watch .........................................................................................................................................................................................................21 About ...............................................................................................................................................................................................................................................23