Variations of Gamma Cassiopeiae
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Visual Double Star Measurements with an Alt-Azimuth Telescope
Vol. 4 No. 2 Spring 2008 Journal of Double Star Observations Page 59 Visual Double Star Measurements with an Alt-Azimuth Telescope Thomas G. Frey California Polytechnic State University San Luis Obispo, CA 93407 Abstract: An alt-az mounted Newtonian telescope was used to determine the separation and position angle of seven known and five neglected double stars. The problem of field rotation was solved by modifying the usual observing technique. Separation and position angle determinations are described, and the standard deviations and mean errors for these measurements are presented. The direction of future studies is outlined. techniques were accurate and precise, additional Introduction measurements on neglected double stars listed in the Professional astronomers have carried out visual Washington Double Star Catalogue were made. double star measurements for over 200 years. These scientists measured the separation between double Double Star Observation: Equatorial vs. stars in arc seconds, and the position angle in degrees Alt-Az Mounts that defined the orientation of pairs with respect to Most observers involved in double star measure- celestial north. Over time, the orbital motion of each ments, including Argyle (p.x) and Teague (p.112), star can create a change in the observed separation recommend the use of equatorial mounted telescopes. and position angle if the pair proves to be binary in Such telescopes have drive motors that are oriented so nature. A binary star revolves around a common the right ascension axis rotates around the north center of mass. celestial pole, canceling out the Earth’s rotation and Today’s amateur astronomers continue to evaluate the image in the eyepiece remains stationary. -
M17 CEN1.Pdf
The Origin of Hard X-rays in M 17's Remarkable O4+O4 Binary M 17, the closest Giant H ii Region (d ≈ 2 kpc), is a superior laboratory for the study of young massive stars. Producing the second-brightest H ii region in the sky (after the Orion Nebula), the OB cluster NGC 6618 has nearly 10,000 members extending up to masses M ≈ 60M (spectral type O4 V) in the central binary. It is a scaled-up, edge-on version of the Orion Molecular Cloud: a blister nebula on the edge of one of the Galaxy's most massive giant molecular clouds. With an age of ∼ 0:5 Myr (Hanson et al. 1997, ApJ 489, 698) and no evolved stars, M 17 is one of the few massive star-forming regions whose massive stars are luminous enough to produce a prominent X-ray outflow (Townsley et al. 2003, ApJ 593, 874) and yet is unlikely to have hosted any supernovae. Co-I's Townsley and Garmire have amassed 320 ks of Chandra ACIS-I time on NGC 6618, through a combination of GO and ACIS GTO programs, to study M 17 and its enormous X-ray champagne flow. The ACIS data reveal that the massive O4 stars in NGC 6618 are a pair of remarkable hard, variable X-ray sources separated by 1:800 (Broos et al. 2007, ApJS 169, 353; Fig. 1A). The stars are seen through AV ≈ 10 mag and no spatially resolved near-infrared photometry or spectroscopy of the visual pair is published. The pair is known historically as Kleinmann's Anonymous Star (Kleinmann 1973, ApL, 14, 39); Chini et al. -
List of Easy Double Stars for Winter and Spring = Easy = Not Too Difficult = Difficult but Possible
List of Easy Double Stars for Winter and Spring = easy = not too difficult = difficult but possible 1. Sigma Cassiopeiae (STF 3049). 23 hr 59.0 min +55 deg 45 min This system is tight but very beautiful. Use a high magnification (150x or more). Primary: 5.2, yellow or white Seconary: 7.2 (3.0″), blue 2. Eta Cassiopeiae (Achird, STF 60). 00 hr 49.1 min +57 deg 49 min This is a multiple system with many stars, but I will restrict myself to the brightest one here. Primary: 3.5, yellow. Secondary: 7.4 (13.2″), purple or brown 3. 65 Piscium (STF 61). 00 hr 49.9 min +27 deg 43 min Primary: 6.3, yellow Secondary: 6.3 (4.1″), yellow 4. Psi-1 Piscium (STF 88). 01 hr 05.7 min +21 deg 28 min This double forms a T-shaped asterism with Psi-2, Psi-3 and Chi Piscium. Psi-1 is the uppermost of the four. Primary: 5.3, yellow or white Secondary: 5.5 (29.7), yellow or white 5. Zeta Piscium (STF 100). 01 hr 13.7 min +07 deg 35 min Primary: 5.2, white or yellow Secondary: 6.3, white or lilac (or blue) 6. Gamma Arietis (Mesarthim, STF 180). 01 hr 53.5 min +19 deg 18 min “The Ram’s Eyes” Primary: 4.5, white Secondary: 4.6 (7.5″), white 7. Lambda Arietis (H 5 12). 01 hr 57.9 min +23 deg 36 min Primary: 4.8, white or yellow Secondary: 6.7 (37.1″), silver-white or blue 8. -
Fundamental Properties of Core-Collapse Supernova and GRB Progenitors: Predicting the Look of Massive Stars Before Death
A&A 558, A131 (2013) Astronomy DOI: 10.1051/0004-6361/201321906 & c ESO 2013 Astrophysics Fundamental properties of core-collapse supernova and GRB progenitors: predicting the look of massive stars before death Jose H. Groh1, Georges Meynet1, Cyril Georgy2, and Sylvia Ekström1 1 Geneva Observatory, Geneva University, Chemin des Maillettes 51, 1290 Sauverny, Switzerland e-mail: [email protected] 2 Astrophysics group, EPSAM, Keele University, Lennard-Jones Labs, ST5 5BG Keele, UK Received 16 May 2013 / Accepted 20 August 2013 ABSTRACT We investigate the fundamental properties of core-collapse supernova (SN) progenitors from single stars at solar metallicity. For this purpose, we combine Geneva stellar evolutionary models with initial masses of Mini = 20−120 M with atmospheric and wind models using the radiative transfer code CMFGEN. We provide synthetic photometry and high-resolution spectra of hot stars at the pre-SN stage. For models with Mini = 9−20 M, we supplement our analysis using publicly available MARCS model atmospheres of RSGs to estimate their synthetic photometry. We employ well-established observational criteria of spectroscopic classification and find that, depending on their initial mass and rotation, massive stars end their lives as red supergiants (RSG), yellow hypergiants (YHG), luminous blue variables (LBV), and Wolf-Rayet (WR) stars of the WN and WO spectral types. For rotating models, we obtained the + following types of SN progenitors: WO1–3 (Mini ≥ 32 M), WN10–11 (25 < Mini < 32 M), LBV (20 ≤ Mini ≤ 25 M), G1 Ia (18 < Mini < 20 M), and RSGs (9 ≤ Mini ≤ 18 M). For non-rotating models, we found spectral types WO1–3 (Mini > 40 M), WN7–8 (25 < Mini ≤ 40 M), WN11h/LBV (20 < Mini ≤ 25 M), and RSGs (9 ≤ Mini ≤ 20 M). -
Stars and Their Spectra: an Introduction to the Spectral Sequence Second Edition James B
Cambridge University Press 978-0-521-89954-3 - Stars and Their Spectra: An Introduction to the Spectral Sequence Second Edition James B. Kaler Index More information Star index Stars are arranged by the Latin genitive of their constellation of residence, with other star names interspersed alphabetically. Within a constellation, Bayer Greek letters are given first, followed by Roman letters, Flamsteed numbers, variable stars arranged in traditional order (see Section 1.11), and then other names that take on genitive form. Stellar spectra are indicated by an asterisk. The best-known proper names have priority over their Greek-letter names. Spectra of the Sun and of nebulae are included as well. Abell 21 nucleus, see a Aurigae, see Capella Abell 78 nucleus, 327* ε Aurigae, 178, 186 Achernar, 9, 243, 264, 274 z Aurigae, 177, 186 Acrux, see Alpha Crucis Z Aurigae, 186, 269* Adhara, see Epsilon Canis Majoris AB Aurigae, 255 Albireo, 26 Alcor, 26, 177, 241, 243, 272* Barnard’s Star, 129–130, 131 Aldebaran, 9, 27, 80*, 163, 165 Betelgeuse, 2, 9, 16, 18, 20, 73, 74*, 79, Algol, 20, 26, 176–177, 271*, 333, 366 80*, 88, 104–105, 106*, 110*, 113, Altair, 9, 236, 241, 250 115, 118, 122, 187, 216, 264 a Andromedae, 273, 273* image of, 114 b Andromedae, 164 BDþ284211, 285* g Andromedae, 26 Bl 253* u Andromedae A, 218* a Boo¨tis, see Arcturus u Andromedae B, 109* g Boo¨tis, 243 Z Andromedae, 337 Z Boo¨tis, 185 Antares, 10, 73, 104–105, 113, 115, 118, l Boo¨tis, 254, 280, 314 122, 174* s Boo¨tis, 218* 53 Aquarii A, 195 53 Aquarii B, 195 T Camelopardalis, -
Variable Star Section Circular
ΒΑΛ The British Astronomical Association VARIABLE STAR SECTION CIRCULAR 64 "LIGHT-CURVE” AUGUST 1986 ISSN 0267-9272 Office: Burlington House, Piccadilly, London, W1V 9AG SECTION OFFICERS: Director D.R.B. Saw, 'Upanova1, 18 Dolllcott, Haddenham, Aylesbury, Bucks. HP17 8JG Tel: Haddenham (0844) 292065 Assistant Director S.R. Dunlop, 140 Stocks Lane, East Wittering, nr Chichester, West Sussex P020 8NT Tel: Bracklesham Bay (0243) 670354 Secretary M.D. Taylor, 17 Cross Lane, Wakefield, West Yorkshire WF2 8DA Tel: Wakefield (0924) 374651 Programme Secretaries: Assistant Secretary (Post temporarily vacant) Telescopic Assistant Secretary J. Toone, 2 Hilton Crescent, Boothstown, Binocular Worsley, Manchester M28 4FY Tel: 061 702 8619 Eclipsing Binary J.E. Isles, Rose Cottage, 22 High Street, Secretary Wescott, Bucks. HP18 OPU Tel: Aylesbury (0296) 651779 Nova/Supernova G.M Hurst, 16 Westminster Close, Search Secretary Kempshott Rise, Basingstoke, Hants. RG22 4PP Tel: Basingstoke (0256) 471074 Chart Secretary J. Parkinson, 229 Scar Lane, Golcar, (except Eclipsing) Huddersfield, West Yorkshire HD7 4AU Tel: Huddersfield (0484) 642947 For subcription rates and charges for charts and other publications see inside back cover. Editorial It has been suggested that these C irc u la rs are often a little 'dry' and technical for some members. We are always happy to receive more 'personal' items and hope to include more in future issues. We are also including an occasional short note on some of the terms encountered, and which may not be fully explained in some of the specific articles. The first such item appears on p.13. If you have any queries, however elementary, please send them in, and we shall do our best to provide the answers. -
Arxiv:2006.10868V2 [Astro-Ph.SR] 9 Apr 2021 Spain and Institut D’Estudis Espacials De Catalunya (IEEC), C/Gran Capit`A2-4, E-08034 2 Serenelli, Weiss, Aerts Et Al
Noname manuscript No. (will be inserted by the editor) Weighing stars from birth to death: mass determination methods across the HRD Aldo Serenelli · Achim Weiss · Conny Aerts · George C. Angelou · David Baroch · Nate Bastian · Paul G. Beck · Maria Bergemann · Joachim M. Bestenlehner · Ian Czekala · Nancy Elias-Rosa · Ana Escorza · Vincent Van Eylen · Diane K. Feuillet · Davide Gandolfi · Mark Gieles · L´eoGirardi · Yveline Lebreton · Nicolas Lodieu · Marie Martig · Marcelo M. Miller Bertolami · Joey S.G. Mombarg · Juan Carlos Morales · Andr´esMoya · Benard Nsamba · KreˇsimirPavlovski · May G. Pedersen · Ignasi Ribas · Fabian R.N. Schneider · Victor Silva Aguirre · Keivan G. Stassun · Eline Tolstoy · Pier-Emmanuel Tremblay · Konstanze Zwintz Received: date / Accepted: date A. Serenelli Institute of Space Sciences (ICE, CSIC), Carrer de Can Magrans S/N, Bellaterra, E- 08193, Spain and Institut d'Estudis Espacials de Catalunya (IEEC), Carrer Gran Capita 2, Barcelona, E-08034, Spain E-mail: [email protected] A. Weiss Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei M¨unchen, D-85741, Germany C. Aerts Institute of Astronomy, Department of Physics & Astronomy, KU Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium and Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands G.C. Angelou Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei M¨unchen, D-85741, Germany D. Baroch J. C. Morales I. Ribas Institute of· Space Sciences· (ICE, CSIC), Carrer de Can Magrans S/N, Bellaterra, E-08193, arXiv:2006.10868v2 [astro-ph.SR] 9 Apr 2021 Spain and Institut d'Estudis Espacials de Catalunya (IEEC), C/Gran Capit`a2-4, E-08034 2 Serenelli, Weiss, Aerts et al. -
Volume 4, Number 5, January 2016
THE STAR THE NEWSLETTER OF THE MOUNT CUBA ASTRONOMICAL GROUP VOL. 4 NUM. 5 CONTACT US AT DAVE GROSKI [email protected] OR HANK BOUCHELLE [email protected] 302-983-7830 OUR PROGRAMS ARE HELD THE SECOND TUESDAY OF EACH MONTH AT 7:30 P.M. UNLESS INDICATED OTHERWISE MOUNT CUBA ASTRONOMICAL OBSERVATORY 1610 HILLSIDE MILL ROAD GREENVILLE, DE FOR DIRECTIONS PLEASE VISIT www.mountcuba.org PLEASE SEND ALL PHOTOS AND ARTICLES TO [email protected] 1 OUR NEXT MEETING TH JANUARY 12 TUESDAY 7:30 p.m. ASTRONOMICAL TERMS AND NAMES OF THE MONTH: The Mission of the Mt. Cuba Astronomy Group is to increase knowledge and expand awareness of the science of astronomy and related technologies. When reading the articles in the STAR, you will come across various terms and names of objects you may not be familiar with. Therefore, in each edition of the STAR, we will review terms as well as objects related to Astronomy and related technologies. These topics are presented on a level that the general public can appreciated. CONSTILLATIONS: Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopeia was one of the 48 constellations listed by the 2nd-century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive 'M' shape when in upper culmination but in higher northern locations when near lower culminations in spring and summer it has a 'W' shape, formed by five bright stars. -
Double and Multiple Star Measurements in the Northern Sky with a 10” Newtonian and a Fast CCD Camera in 2006 Through 2009
Vol. 6 No. 3 July 1, 2010 Journal of Double Star Observations Page 180 Double and Multiple Star Measurements in the Northern Sky with a 10” Newtonian and a Fast CCD Camera in 2006 through 2009 Rainer Anton Altenholz/Kiel, Germany e-mail: rainer.anton”at”ki.comcity.de Abstract: Using a 10” Newtonian and a fast CCD camera, recordings of double and multiple stars were made at high frame rates with a notebook computer. From superpositions of “lucky images”, measurements of 139 systems were obtained and compared with literature data. B/w and color images of some noteworthy systems are also presented. mented double stars, as will be described in the next Introduction section. Generally, I used a red filter to cope with By using the technique of “lucky imaging”, seeing chromatic aberration of the Barlow lens, as well as to effects can strongly be reduced, and not only the reso- reduce the atmospheric spectrum. For systems with lution of a given telescope can be pushed to its limits, pronounced color contrast, I also made recordings but also the accuracy of position measurements can be with near-IR, green and blue filters in order to pro- better than this by about one order of magnitude. This duce composite images. This setup was the same as I has already been demonstrated in earlier papers in used with telescopes under the southern sky, and as I this journal [1-3]. Standard deviations of separation have described previously [1-3]. Exposure times varied measurements of less than +/- 0.05 msec were rou- between 0.5 msec and 100 msec, depending on the tinely obtained with telescopes of 40 or 50 cm aper- star brightness, and on the seeing. -
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. -
Supernova Star Maps
Supernova Star Maps Which Stars in the Night Sky Will Go Su pernova? About the Activity Allow visitors to experience finding stars in the night sky that will eventually go supernova. Topics Covered Observation of stars that will one day go supernova Materials Needed • Copies of this month's Star Map for your visitors- print the Supernova Information Sheet on the back. • (Optional) Telescopes A S A Participants N t i d Activities are appropriate for families Cre with children over the age of 9, the general public, and school groups ages 9 and up. Any number of visitors may participate. Location and Timing This activity is perfect for a star party outdoors and can take a few minutes, up to 20 minutes, depending on the Included in This Packet Page length of the discussion about the Detailed Activity Description 2 questions on the Supernova Helpful Hints 5 Information Sheet. Discussion can start Supernova Information Sheet 6 while it is still light. Star Maps handouts 7 Background Information There is an Excel spreadsheet on the Supernova Star Maps Resource Page that lists all these stars with all their particulars. Search for Supernova Star Maps here: http://nightsky.jpl.nasa.gov/download-search.cfm © 2008 Astronomical Society of the Pacific www.astrosociety.org Copies for educational purposes are permitted. Additional astronomy activities can be found here: http://nightsky.jpl.nasa.gov Star Maps: Stars likely to go Supernova! Leader’s Role Participants’ Role (Anticipated) Materials: Star Map with Supernova Information sheet on back Objective: Allow visitors to experience finding stars in the night sky that will eventually go supernova.