Eclipsing Systems with Pulsating Components (Types Β Cep, Δ Sct, Γ Dor Or Red Giant) in the Era of High-Accuracy Space Data
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Fine-Structure Feii and Siii Absorption in the Spectrum of GRB 051111
Draft version November 11, 2018 Preprint typeset using LATEX style emulateapj Fine-Structure Fe II and Si II Absorption in the Spectrum of GRB051111: Implications for the Burst Environment E. Berger1,2,3, B. E. Penprase4, D. B. Fox5, S. R. Kulkarni6, G. Hill7, B. Schaefer7, and M. Reed7 Draft version November 11, 2018 ABSTRACT We present an analysis of fine-structure transitions of Fe II and Si II detected in a high-resolution optical spectrum of the afterglow of GRB051111 (z =1.54948). The fine-structure absorption features arising from Fe II* to Fe II****, as well as Si II*, are confined to a narrow velocity structure extending over ±30 km s−1, which we interpret as the burst local environment, most likely a star forming region. We investigate two scenarios for the excitation of the fine-structure levels by collisions with electrons and radiative pumping by an infra-red or ultra-violet radiation field produced by intense star formation in the GRB environment, or by the GRB afterglow itself. We find that the conditions required for collisional excitation of Fe II fine-structure states cannot be easily reconciled with the relatively weak Si II* absorption. Radiative pumping by either IR or UV emission requires > 103 massive hot OB stars within a compact star-forming region a few pc in size, and in the case of IR pumping a large dust content. On the other hand, it is possible that the GRB itself provides the source of IR and/or UV radiation, in which case we estimate that the excitation takes place at a distance of ∼ 10 − 20 pc from the burst. -
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 Please do not quote from it without prior permission from the AAVSO.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. -
Solar Physics
INDI~T INS~ITUTE ~F AS~ROPHYSIC~ Annual Report fer the year April 1,1975 to March 31,1976. SOLAR PHYSICS An investigation on the emission line width in the '~-line of ionized calcium in be chromospheres of the Sun and the late type stars has been completed by Bappu and Sivaraman. !hcro- meter measures of the emission line width on the integrated spectra of the sun yield a near value of 38.2 kID/sec. From similar measures of the Spectra of 22 other stars and from their K-line profiles, a definition is proposed whereby the emission line width is a measure in km/sec at the e-1 value of the diffe~ce between the intensity of "(ihe brighter "[2 peak over the Kl background reckoned from the latter level. The K-line . profi+e of the integrated spectrum of the sLUl(po~ses~ -~d th'> .~~ . in excess of the widths seen in the averaged spe~~over 1-\:·J.)::"~1. .\ different parts of the solar disc. The increase in width of the K line profiles near the limb over those at the centre of the disc can account only for a minor share of this excess. The principal contributor is the solar rotation, Since the regions farther away from the centre will contribute more to the integ~ated behaviour than the centre itself. This shows the imperative need to use a solar value derived from a truly integrated spectrum for any calibration of width with absolute magnitude. It is shown that the K-emission profile observed in other stars is that of the typical bright mottle, which is a very important entity in the derivation of'the parameters pertaining to t he chromosphere. -
Tidally Induced Pulsations in Kepler Eclipsing Binary KIC 3230227
09/14/2016 Tidally Induced Pulsations in Kepler Eclipsing Binary KIC 3230227 Zhao Guo, Douglas R. Gies Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P. O. Box 5060, Atlanta, GA 30302-5060, USA; [email protected], [email protected] Jim Fuller TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, Caltech, Pasadena, CA 91125, USA; Kavli Institute for Theoretical Physics, Kohn Hall, University of California, Santa Barbara, CA 93106, USA; [email protected] ABSTRACT KIC 3230227 is a short period (P ≈ 7:0 days) eclipsing binary with a very eccentric orbit (e = 0:6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M1 = 1:84 ± 0:18M , M2 = 1:73 ± 0:17M and radii of R1 = 2:01 ± 0:09R , R2 = 1:68±0:08R for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system. After removing the binary light curve model, more than ten pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l = 2; m = −2 prograde modes. 1. Introduction Heartbeat stars (HBs), named after the resemblance between their light curves and electrocardiogram, are binary or multiple systems with very eccentric orbits. -
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. -
A Search for Beta Cephei Stars in the Southern Hemisphere C
A Search for Beta Cephei Stars in the Southern Hemisphere C. Sterken, M. Jerzykiewicz they were too bright for photometric observation (in this The present article is another illustration of new, case it was impossible to find suitable comparison stars). exciting work in the southern hemisphere which is For each programme star two nearby comparison stars still largely unexplored when compared to the with similar spectral type and brightness were chosen. Be northern. Drs. Christiaan Sterken and Mikofaj Jerzy cause telescope time was the limiting factor, a number of programme stars were purposely selected as com kiewicz have during the past years been looking for parison stars. new, relatively bright variable stars of the ßCephei type south of-20°. The observations were made by Observations on La Silla Dr. Sterken, who was formerly with ESO in Chile, Ouring the first observing run in the period between No and who will spend another year at the Landes vember 24 and Oecember 31, 1975 (32 nights) nearly one sternwarte Heidelberg-Königstuhl, FRG, before he thousand photoelectric observations of 68 programme returns to his native Belgium. Dr. Jerzykiewicz stars were obtained with the four-channel uvby photome made the reductions with the ODRA 1204 computer ter attached to the Oanish 50 cm telescope at La Silla. The of the University of Wroclaw, Poland. differential observations were programmed in such a way, as to make most likely the discovery of light variation with time scales of about three to seven hours. At least four One of the main reasons for studying ßCephei-type vari measurements for the same triplet: "first comparison star ables seems to come from the fact that the causes under programme star - second comparison star" was obtained Iying their oscillations are still unknown. -
Pulsating Components in Binary and Multiple Stellar Systems---A
Research in Astron. & Astrophys. Vol.15 (2015) No.?, 000–000 (Last modified: — December 6, 2014; 10:26 ) Research in Astronomy and Astrophysics Pulsating Components in Binary and Multiple Stellar Systems — A Catalog of Oscillating Binaries ∗ A.-Y. Zhou National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China; [email protected] Abstract We present an up-to-date catalog of pulsating binaries, i.e. the binary and multiple stellar systems containing pulsating components, along with a statistics on them. Compared to the earlier compilation by Soydugan et al.(2006a) of 25 δ Scuti-type ‘oscillating Algol-type eclipsing binaries’ (oEA), the recent col- lection of 74 oEA by Liakos et al.(2012), and the collection of Cepheids in binaries by Szabados (2003a), the numbers and types of pulsating variables in binaries are now extended. The total numbers of pulsating binary/multiple stellar systems have increased to be 515 as of 2014 October 26, among which 262+ are oscillating eclipsing binaries and the oEA containing δ Scuti componentsare updated to be 96. The catalog is intended to be a collection of various pulsating binary stars across the Hertzsprung-Russell diagram. We reviewed the open questions, advances and prospects connecting pulsation/oscillation and binarity. The observational implication of binary systems with pulsating components, to stellar evolution theories is also addressed. In addition, we have searched the Simbad database for candidate pulsating binaries. As a result, 322 candidates were extracted. Furthermore, a brief statistics on Algol-type eclipsing binaries (EA) based on the existing catalogs is given. We got 5315 EA, of which there are 904 EA with spectral types A and F. -
Stars, Constellations, and Dsos [50 Pts]
Reach for the Stars B – KEY Bonus (+1) TRAPPIST-1 Part I: Stars, Constellations, and DSOs [50 pts] 1. Kepler’s SNR 2. Tycho’s SNR 3. M16 (Eagle Nebula) 4. Radiation pressure (wind) from young stars 5. Cas A 6. Extinction (from interstellar dust) 7. 30 Dor 8. [T10] Tarantula Nebula 9. LMC 10. Sgr A* 11. Gravitational interaction with orbiting stars (based on movement over time) 12. M42 (Orion Nebula) 13. [T8] Trapezium 14. (Charles) Messier 15. NGC 7293 (Helix Nebula) –OR– M57 (Ring Nebula) 16. TP-AGB (thermal pulse AGB) 17. Binary system –OR– stellar winds –OR– stellar rotation –OR– magnetic fields 18. Geminga 19. [T4] Jets from pulsar spin poles 20. X-ray 21. NGC 3603 22. Among the most massive & luminous stars known 23. T Tauri 24. FUors (FU Orionis stars) 25. NGC 602 26. Open cluster 27. LMC –AND– SMC 28. Irregular 29. Tidal forces –OR– gravity of MW 30. M1 (Crab Nebula) 31. PWN (pulsar wind nebula) 32. X-ray 33. M17 (Omega Nebula) 34. Omega Nebula –OR– Swan Nebula –OR– Checkmark Nebula –OR– Horseshoe Nebula 35. NGC 6618 36. Zeta Ophiuchi 37. Bow shock (from moving quickly through the ISM) 38. It “wobbles” across the sky (moves perpendicular to overall proper motion) 39. Procyon (α CMi) 40. Mizar –AND– Alcor 41. Mizar 42. Pollux (β Gem) 43. [T5] High rotational velocity 44. Altair (α Aql) –OR– Regulus (α Leo) –OR– Vega (α Lyr) 45. Polaris (α UMi) 46. Precession 47. Binary with observed Doppler shift of spectral lines 48. Beta Cephei variable (β Cep) 49. -
Tidally Trapped Pulsations in a Close Binary Star System Discovered by TESS G
Tidally Trapped Pulsations in a close binary star system discovered by TESS G. Handler,1 D. W. Kurtz,2 S. A. Rappaport,3 H. Saio,4 J. Fuller,5 D. Jones,6; 7 Z. Guo,8 S. Chowdhury,1 P. Sowicka,1 F. Kahraman Ali¸cavu¸s,1; 9 M. Streamer,10 S. J. Murphy,11 R. Gagliano,12 T. L. Jacobs13 and A. Vanderburg 14; 15 Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716, Warsaw, Poland 2 Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK 3 Department of Physics, and Kavli Institute for Astrophysics and Space Research, M.I.T., Cambridge, MA 02139, USA 4 Astronomical Institute, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan 5 Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 6 Instituto de Astrof´ısicade Canarias, E-38205 La Laguna, Tenerife, Spain 7 Departamento de Astrof´ısica,Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain 8 Department of Astronomy and Astrophysics, Pennsylvania State University, 421 Davey Lab, University Park, PA 16802, USA 9 C¸anakkale Onsekiz Mart University, Faculty of Sciences and Arts, Physics Department, 17100, C¸anakkale, Turkey 10 Research School of Astronomy and Astrophysics, Australian National University, Can- berra, ACT, Australia 11 Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia 12 Planet Hunters 13 Amateur Astronomer, 12812 SE 69th Place Bellevue, WA 98006, USA 14 Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712, USA 15 NASA Sagan Fellow arXiv:2003.04071v1 [astro-ph.SR] 9 Mar 2020 1 It has long been suspected that tidal forces in close binary stars could modify the orientation of the pulsation axis of the constituent stars. -
Periodic Brightening of Kepler Light Curves: Investigating the Possibility of Forward Scattering Due to Dust Clouds
MNRAS 499, 2817–2825 (2020) doi:10.1093/mnras/staa3048 Advance Access publication 2020 October 2 Periodic brightening of Kepler light curves: investigating the possibility of forward scattering due to dust clouds M. A. M. van Kooten ,1‹ M. Kenworthy 1 and N. Doelman1,2 1Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, the Netherlands 2TNO, Stieltjesweg 1, 2628 CK Delft, the Netherlands Accepted 2020 September 29. Received 2020 September 25; in original form 2020 April 24 Downloaded from https://academic.oup.com/mnras/article/499/2/2817/5917438 by guest on 11 November 2020 ABSTRACT Dedicated transiting surveys, such as the Kepler space telescope, have provided the astronomy community with a rich data set resulting in many new discoveries. In this paper, we look at eight Kepler objects identified by Wheeler & Kipping with a periodic, broad increase in flux, that look distinctly different from intrinsic star variability. We consider two physical phenomena as explanations for these observed Kepler light curves; the first being the classical explanation while the second being an alternative scenario: (i) tidal interactions in a binary star system, and (ii) forward scattering from an optically thin cloud around an exoplanet. We investigate the likelihood of each model by modelling and fitting to the observed data. The binary system qualitatively does a good job of reproducing the shape of the observed light curves due to the tidal interaction of the two stars. We do, however, see a mismatch in flux right before or after the peak brightness. We find that six out of the eight systems require an F-type primary star with a K-type companion with large eccentricities. -
Macrocosmo Nº33
HA MAIS DE DOIS ANOS DIFUNDINDO A ASTRONOMIA EM LÍNGUA PORTUGUESA K Y . v HE iniacroCOsmo.com SN 1808-0731 Ano III - Edição n° 33 - Agosto de 2006 * t i •■•'• bSÈlÈWW-'^Sif J fé . ’ ' w s » ws» ■ ' v> í- < • , -N V Í ’\ * ' "fc i 1 7 í l ! - 4 'T\ i V ■ }'- ■t i' ' % r ! ■ 7 ji; ■ 'Í t, ■ ,T $ -f . 3 j i A 'A ! : 1 l 4/ í o dia que o ceu explodiu! t \ Constelação de Andrômeda - Parte II Desnudando a princesa acorrentada £ Dicas Digitais: Softwares e afins, ATM, cursos online e publicações eletrônicas revista macroCOSMO .com Ano III - Edição n° 33 - Agosto de I2006 Editorial Além da órbita de Marte está o cinturão de asteróides, uma região povoada com Redação o material que restou da formação do Sistema Solar. Longe de serem chamados como simples pedras espaciais, os asteróides são objetos rochosos e/ou metálicos, [email protected] sem atmosfera, que estão em órbita do Sol, mas são pequenos demais para serem considerados como planetas. Até agora já foram descobertos mais de 70 Diretor Editor Chefe mil asteróides, a maior parte situados no cinturão de asteróides entre as órbitas Hemerson Brandão de Marte e Júpiter. [email protected] Além desse cinturão podemos encontrar pequenos grupos de asteróides isolados chamados de Troianos que compartilham a mesma órbita de Júpiter. Existem Editora Científica também aqueles que possuem órbitas livres, como é o caso de Hidalgo, Apolo e Walkiria Schulz Ícaro. [email protected] Quando um desses asteróides cruza a nossa órbita temos as crateras de impacto. A maior cratera visível de nosso planeta é a Meteor Crater, com cerca de 1 km de Diagramadores diâmetro e 600 metros de profundidade.