The Evolution of Massive Stars in the Small Magellanic Cloud
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Wolf-Rayet Stars in the Small Magellanic Cloud II
A&A 591, A22 (2016) DOI: 10.1051/0004-6361/201527916 Astronomy c ESO 2016 & Astrophysics Wolf-Rayet stars in the Small Magellanic Cloud II. Analysis of the binaries T. Shenar1, R. Hainich1, H. Todt1, A. Sander1, W.-R. Hamann1, A. F. J. Moffat2, J. J. Eldridge3, H. Pablo2, L. M. Oskinova1, and N. D. Richardson4 1 Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany e-mail: [email protected] 2 Département de physique and Centre de Recherche en Astrophysique du Québec (CRAQ), Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada 3 Department of Physics, University of Auckland, Private Bag, 92019 Auckland, New Zealand 4 Ritter Observatory, Department of Physics and Astronomy, The University of Toledo, Toledo, OH 43606-3390, USA Received 8 December 2015 / Accepted 30 March 2016 ABSTRACT Context. Massive Wolf-Rayet (WR) stars are evolved massive stars (Mi & 20 M ) characterized by strong mass-loss. Hypothetically, they can form either as single stars or as mass donors in close binaries. About 40% of all known WR stars are confirmed binaries, raising the question as to the impact of binarity on the WR population. Studying WR binaries is crucial in this context, and furthermore enable one to reliably derive the elusive masses of their components, making them indispensable for the study of massive stars. Aims. By performing a spectral analysis of all multiple WR systems in the Small Magellanic Cloud (SMC), we obtain the full set of stellar parameters for each individual component. -
The Wolf-Rayet + of Star Binary AB7: a Warmer in the Small Magellanic Cloud+)
The Wolf-Rayet + Of star binary AB7: A Warmer in the Small Magellanic Cloud+) Manfred W. Pakull1) & Luciana Bianchi2) 1) Observatoire de Besançon, 25044 Besançon Cedex, France 2) Osservatorio Astronomico di Turino, 10025 Pino Torinese, Italy Summary Strong nebular Hell λ4686 recombination radiation (λ4686/Ηβ = 0.2) has recently been detected in the bright HII region N76 in the Small Magellanic Cloud by Testor & Pakull (1989). The rather symmetric intensity distribution suggests a nebular morphology which consists of a thick outer shell comprising the He*"1* and H+ ionization fronts and a central region of warm, highly ionized gas which is surrounded by a hollow inner shell. The source of the high nebular ionization is identified with the peculiar Wolf-Rayet + Of star spectroscopic binary AB7. Optical and UV spectra (cf. Figure) show in addition to hydrogen and helium absorption lines and the NIII λλ4634-41 complex from the Of star, only broad He II and weak NVemission lines due to the Wolf-Rayet companion. The absence of other diagnostic features qualifies the evolved component as a rare, high-excitation WN star (WN2 or WN1). Subtracting from the optical spectrum of AB7 suitably scaled spectra of SMC Ο stars up to the point that the absorption lines disappeared, suggests that the WN 1 component contributes about 30 % to the total optical light. ' 4000 4500 5000 5500 °' üoö ' iioö t7Ö5 üoö" Wavelength (A) WAVELENGTH (AI Optical and IUE spectra of the 06 IIIf+ WN1 binary AB 7 From the nebular λ4686 flux and the optical brightness of the WN1 star a black body Zanstra temperature of about 80 000 Κ and a luminosity of 106 Lo are derived. -
The Wolf-Rayet + of Star Binary AB7: a Warmer in the Small Magellanic Cloud+)
The Wolf-Rayet + Of star binary AB7: A Warmer in the Small Magellanic Cloud+) Manfred W. Pakull1) & Luciana Bianchi2) 1) Observatoire de Besançon, 25044 Besançon Cedex, France 2) Osservatorio Astronomico di Turino, 10025 Pino Torinese, Italy Summary Strong nebular Hell λ4686 recombination radiation (λ4686/Ηβ = 0.2) has recently been detected in the bright HII region N76 in the Small Magellanic Cloud by Testor & Pakull (1989). The rather symmetric intensity distribution suggests a nebular morphology which consists of a thick outer shell comprising the He*"1* and H+ ionization fronts and a central region of warm, highly ionized gas which is surrounded by a hollow inner shell. The source of the high nebular ionization is identified with the peculiar Wolf-Rayet + Of star spectroscopic binary AB7. Optical and UV spectra (cf. Figure) show in addition to hydrogen and helium absorption lines and the NIII λλ4634-41 complex from the Of star, only broad He II and weak NVemission lines due to the Wolf-Rayet companion. The absence of other diagnostic features qualifies the evolved component as a rare, high-excitation WN star (WN2 or WN1). Subtracting from the optical spectrum of AB7 suitably scaled spectra of SMC Ο stars up to the point that the absorption lines disappeared, suggests that the WN 1 component contributes about 30 % to the total optical light. ' 4000 4500 5000 5500 °' üoö ' iioö t7Ö5 üoö" Wavelength (A) WAVELENGTH (AI Optical and IUE spectra of the 06 IIIf+ WN1 binary AB 7 From the nebular λ4686 flux and the optical brightness of the WN1 star a black body Zanstra temperature of about 80 000 Κ and a luminosity of 106 Lo are derived. -
Download the 2016 Spring Deep-Sky Challenge
Deep-sky Challenge 2016 Spring Southern Star Party Explore the Local Group Bonnievale, South Africa Hello! And thanks for taking up the challenge at this SSP! The theme for this Challenge is Galaxies of the Local Group. I’ve written up some notes about galaxies & galaxy clusters (pp 3 & 4 of this document). Johan Brink Peter Harvey Late-October is prime time for galaxy viewing, and you’ll be exploring the James Smith best the sky has to offer. All the objects are visible in binoculars, just make sure you’re properly dark adapted to get the best view. Galaxy viewing starts right after sunset, when the centre of our own Milky Way is visible low in the west. The edge of our spiral disk is draped along the horizon, from Carina in the south to Cygnus in the north. As the night progresses the action turns north- and east-ward as Orion rises, drawing the Milky Way up with it. Before daybreak, the Milky Way spans from Perseus and Auriga in the north to Crux in the South. Meanwhile, the Large and Small Magellanic Clouds are in pole position for observing. The SMC is perfectly placed at the start of the evening (it culminates at 21:00 on November 30), while the LMC rises throughout the course of the night. Many hundreds of deep-sky objects are on display in the two Clouds, so come prepared! Soon after nightfall, the rich galactic fields of Sculptor and Grus are in view. Gems like Caroline’s Galaxy (NGC 253), the Black-Bottomed Galaxy (NGC 247), the Sculptor Pinwheel (NGC 300), and the String of Pearls (NGC 55) are keen to be viewed. -
Characterization of Solar X-Ray Response Data from the REXIS Instrument Andrew T. Cummings
Characterization of Solar X-ray Response Data from the REXIS Instrument by Andrew T. Cummings Submitted to the Department of Earth, Atmospheric, and Planetary Sciences in partial fulfillment of the requirements for the degree of Bachelor of Science in Earth, Atmospheric, and Planetary Sciences at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2020 ○c Massachusetts Institute of Technology 2020. All rights reserved. Author................................................................ Department of Earth, Atmospheric, and Planetary Sciences May 18, 2020 Certified by. Richard P. Binzel Professor of Planetary Sciences Thesis Supervisor Certified by. Rebecca A. Masterson Principal Research Scientist Thesis Supervisor Accepted by . Richard P. Binzel Undergraduate Officer, Department of Earth, Atmospheric, and Planetary Sciences 2 Characterization of Solar X-ray Response Data from the REXIS Instrument by Andrew T. Cummings Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on May 18, 2020, in partial fulfillment of the requirements for the degree of Bachelor of Science in Earth, Atmospheric, and Planetary Sciences Abstract The REgolith X-ray Imaging Spectrometer (REXIS) is a student-built instrument that was flown on NASA’s Origins, Spectral Interpretation, Resource Identification, Safety, Regolith Explorer (OSIRIS-REx) mission. During the primary science ob- servation phase, the REXIS Solar X-ray Monitor (SXM) experienced a lower than anticipated solar x-ray count rate. Solar x-ray count decreased most prominently in the low energy region of instrument detection, and made calibrating the REXIS main spectrometer difficult. This thesis documents a root cause investigation intothe cause of the low x-ray count anomaly in the SXM. Vulnerable electronic components are identified, and recommendations for hardware improvements are made to better facilitate future low-cost, high-risk instrumentation. -
Atlas Menor Was Objects to Slowly Change Over Time
C h a r t Atlas Charts s O b by j Objects e c t Constellation s Objects by Number 64 Objects by Type 71 Objects by Name 76 Messier Objects 78 Caldwell Objects 81 Orion & Stars by Name 84 Lepus, circa , Brightest Stars 86 1720 , Closest Stars 87 Mythology 88 Bimonthly Sky Charts 92 Meteor Showers 105 Sun, Moon and Planets 106 Observing Considerations 113 Expanded Glossary 115 Th e 88 Constellations, plus 126 Chart Reference BACK PAGE Introduction he night sky was charted by western civilization a few thou - N 1,370 deep sky objects and 360 double stars (two stars—one sands years ago to bring order to the random splatter of stars, often orbits the other) plotted with observing information for T and in the hopes, as a piece of the puzzle, to help “understand” every object. the forces of nature. The stars and their constellations were imbued with N Inclusion of many “famous” celestial objects, even though the beliefs of those times, which have become mythology. they are beyond the reach of a 6 to 8-inch diameter telescope. The oldest known celestial atlas is in the book, Almagest , by N Expanded glossary to define and/or explain terms and Claudius Ptolemy, a Greco-Egyptian with Roman citizenship who lived concepts. in Alexandria from 90 to 160 AD. The Almagest is the earliest surviving astronomical treatise—a 600-page tome. The star charts are in tabular N Black stars on a white background, a preferred format for star form, by constellation, and the locations of the stars are described by charts. -
Stellar Rotation the Missing Piece in Stellar Physics
Stellar rotation the missing piece in Stellar physics Collaborators: Richard de Grijs (MQ), Licai Deng (NAOC), Chengyuan Li (SYSU), Michael Albrow (UC), Petri Vaisanen (SAAO), Zara Randriamanakoto (SAAO) Weijia Sun (PKU) 07/14/2021 Why stellar rotation is important? Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Matt & Pudritz 2005 Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Maeder & Meynet 2011 Why stellar rotation is important? • Dynamo-driven magnetic activity • Stellar winds • Surface abundances • Chemical yields • Internal structure • External structure Rivinius+2013 extended MSTO and split MS Found in Magellanic Clouds clusters rMS bMS NGC 1846 NGC 1856 1.5 Gyr 350 Myr Mackey et al. 2008 Milone et al. 2015 Not only in MC clusters Niederhofer et al. 2015 But also in Galactic OCs Pattern NGC 5822 0.9 Gyr Sun et al. 2019a Cordoni et al. 2018 What causes eMSTO and split MS? • Extended star formation history (eSFH) • Variability • A wide range of stellar rotations What causes eMSTO and split MS? Stellar rotation 300 0.0 250 Gravity darkening 0.5 1.0 200 (mag) 1.5 150 G M 2.0 100 2.5 50 pole-on (i = 0) 3.0 0.2 0.4 0.6 G G (mag) BP ° RP edge-on (i = 90) It’s mainly v sin i that affects the locus of a star in the CMD Georgy et al. -
Arxiv:1803.10763V1 [Astro-Ph.GA] 28 Mar 2018
Draft version October 10, 2018 Typeset using LATEX default style in AASTeX61 TRACERS OF STELLAR MASS-LOSS - II. MID-IR COLORS AND SURFACE BRIGHTNESS FLUCTUATIONS Rosa A. Gonzalez-L´ opezlira´ 1 1Instituto de Radioastronomia y Astrofisica, UNAM, Campus Morelia, Michoacan, Mexico, C.P. 58089 (Received 2017 October 20; Revised 2018 February 20; Accepted 2018 February 21) Submitted to ApJ ABSTRACT I present integrated colors and surface brightness fluctuation magnitudes in the mid-IR, derived from stellar popula- tion synthesis models that include the effects of the dusty envelopes around thermally pulsing asymptotic giant branch (TP-AGB) stars. The models are based on the Bruzual & Charlot CB∗ isochrones; they are single-burst, range in age from a few Myr to 14 Gyr, and comprise metallicities between Z = 0.0001 and Z = 0.04. I compare these models to mid-IR data of AGB stars and star clusters in the Magellanic Clouds, and study the effects of varying self-consistently the mass-loss rate, the stellar parameters, and the output spectra of the stars plus their dusty envelopes. I find that models with a higher than fiducial mass-loss rate are needed to fit the mid-IR colors of \extreme" single AGB stars in the Large Magellanic Cloud. Surface brightness fluctuation magnitudes are quite sensitive to metallicity for 4.5 µm and longer wavelengths at all stellar population ages, and powerful diagnostics of mass-loss rate in the TP-AGB for intermediater-age populations, between 100 Myr and 2-3 Gyr. Keywords: stars: AGB and post{AGB | stars: mass-loss | Magellanic Clouds | infrared: stars | stars: evolution | galaxies: stellar content arXiv:1803.10763v1 [astro-ph.GA] 28 Mar 2018 Corresponding author: Rosa A. -
The Electric Sun Hypothesis
Basics of astrophysics revisited. II. Mass- luminosity- rotation relation for F, A, B, O and WR class stars Edgars Alksnis [email protected] Small volume statistics show, that luminosity of bright stars is proportional to their angular momentums of rotation when certain relation between stellar mass and stellar rotation speed is reached. Cause should be outside of standard stellar model. Concept allows strengthen hypotheses of 1) fast rotation of Wolf-Rayet stars and 2) low mass central black hole of the Milky Way. Keywords: mass-luminosity relation, stellar rotation, Wolf-Rayet stars, stellar angular momentum, Sagittarius A* mass, Sagittarius A* luminosity. In previous work (Alksnis, 2017) we have shown, that in slow rotating stars stellar luminosity is proportional to spin angular momentum of the star. This allows us to see, that there in fact are no stars outside of “main sequence” within stellar classes G, K and M. METHOD We have analyzed possible connection between stellar luminosity and stellar angular momentum in samples of most known F, A, B, O and WR class stars (tables 1-5). Stellar equatorial rotation speed (vsini) was used as main parameter of stellar rotation when possible. Several diverse data for one star were averaged. Zero stellar rotation speed was considered as an error and corresponding star has been not included in sample. RESULTS 2 F class star Relative Relative Luminosity, Relative M*R *eq mass, M radius, L rotation, L R eq HATP-6 1.29 1.46 3.55 2.950 2.28 α UMi B 1.39 1.38 3.90 38.573 26.18 Alpha Fornacis 1.33 -
The Bennett Catalogue
The Bennett Catalogue www.macastro.org.au Catalogue Numbers Type R.A. Dec. U2000 Con. Ben 1 NGC 55 Gal 0:14:54 -39:11 386 Scl Ben 2 NGC 104 GC 0:24:06 -72:05 440 Tuc Ben 3 NGC 247 Gal 0:47:06 -20:46 306 Cet Ben 4 NGC 253 Gal 0:47:36 -25:17 306 Scl Ben 5 NGC 288 GC 0:52:48 -26:35 307 Scl Ben 6 NGC 300 Gal 0:54:54 -37:41 351 Scl Ben 7 NGC 362 GC 1:03:12 -70:51 441 Tuc Ben 8 NGC 613 Gal 1:34:18 -29:25 352 Scl Ben 9 NGC 1068 Gal 2:42:42 -00:01 220 Cet Ben 10 NGC 1097 Gal 2:46:18 -30:17 354 For Ben 10a NGC 1232 Gal 3:09:48 -20:35 311 Eri Ben 11 NGC 1261 GC 3:12:18 -55:13 419 Hor Ben 12 NGC 1291 Gal 3:17:18 -41:08 390 Eri Ben 13 NGC 1313 Gal 3:18:18 -66:30 443 Ret Ben 14 NGC 1316 Gal 3:22:42 -37:12 355 For Ben 14a NGC 1350 Gal 3:31:06 -33:38 355 For Ben 15 NGC 1360 PN 3:33:18 -25:51 312 For Ben 16 NGC 1365 Gal 3:33:36 -36:08 355 For Ben 17 NGC 1380 Gal 3:36:30 -34:59 355 For Ben 18 NGC 1387 Gal 3:37:00 -35:31 355 For Ben 19 NGC 1399 Gal 3:38:30 -35:27 355 For Ben 19a NGC 1398 Gal 3:38:54 -26:20 312 For Ben 20 NGC 1404 Gal 3:38:54 -35:35 355 Eri Ben 21 NGC 1433 Gal 3:42:00 -47:13 391 Hor Ben 21a NGC 1512 Gal 4:03:54 -43:21 391 Hor Ben 22 NGC 1535 PN 4:14:12 -12:44 268 Eri Ben 23 NGC 1549 Gal 4:15:42 -55:36 420 Dor Ben 24 NGC 1553 Gal 4:16:12 -55:47 420 Dor Ben 25 NGC 1566 Gal 4:20:00 -54:56 420 Dor Ben 25a NGC 1617 Gal 4:31:42 -54:36 421 Dor Ben 26 NGC 1672 Gal 4:45:42 -59:15 421 Dor Ben 27 NGC 1763 BN 4:56:48 -66:24 444 Dor Ben 28 NGC 1783 GC 4:58:54 -66:00 444 Dor Ben 29 NGC 1792 Gal 5:05:12 -37:59 358 Col -
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UNIVERSO LQ NÚMERO 2 AÑO DE 2012 Revista trimestral gratuita de Latinquasar.org TECNOLOGÍA ESPACIAL Japón en el espacio CIELO AUSTRAL La gran nube de Magallanes HISTORIA DE LA ASTRONOMÍA Los Mayas y el fin del mundo ASTROBIOLOGÍA Bioquímicas alternativas ASTROBRICOLAJE Montura Eq6, toma de contacto SISTEMA SOLAR Y CUERPOS MENORES Lovejoy ASTROCACHARROS NUESTRAS FOTOGRAFÍAS EFEMÉRIDES COMETAS CALENDARIO DE LANZAMIENTOS CRÓNICAS EN ESTE NÚMERO ENCONTRARÁS TECNOLOGÍA ESPACIAL Japón en el espacio...........................................................................................................Página 3 CALENDARIO DE LANZAMIENTOS Calendario de lanzamientos..............................................................................................Página 9 SISTEMA SOLAR Y CUERPOS MENORES Cometas de Enero,Febrero y Marzo...............................................................................Página 18 SISTEMA SOLAR Y CUERPOS MENORES II Cometa Lovejoy................................................................................................................Página 26 CIELO AUSTRAL La gran nube de Magallanes...........................................................................................Página 37 HISTORIA DE LA ASTRONOMÍA Los conocimientos astronómicos de los Mayas y el fenómeno 2012........................Página 41 ASTROBIOLOGÍA Bioquímicas hipotéticas.................................................................................................Página 47 ASTROBRICOLAJE Eq6, más de diez años acompañandonos en las frías -
The Messenger
Czech Republic joins ESO The Messenger Progress on ALMA CRIRES Science Verification Gender balance among ESO staff No. 128 – JuneNo. 2007 The Organisation The Czech Republic Joins ESO Catherine Cesarsky The XXVIth IAU General Assembly, held This Agreement was formally confirmed (ESO Director General) in Prague in 2006, clearly provided a by the ESO Council at its meeting on boost for the Czech efforts to join ESO, 6 December and a few days thereafter by not the least in securing the necessary the Czech government, enabling a sign- I am delighted to welcome the Czech public and political support. Thus our ing ceremony in Prague on 22 December Republic as our 13th member state. From Czech colleagues used the opportunity (see photograph below). This was impor- its size, the Czech Republic may not be- to publish a fine and very interesting pop- tant because the Agreement foresaw long to the ‘big’ member states, but the ular book about Czech astronomy and accession by 1 January 2007. With the accession nonetheless marks an impor- ESO, which, together with the General signatures in place, the agreement could tant point in ESO’s history and, I believe, Assembly, created considerable media be submitted to the Czech Parliament in the history of Czech astronomy as well. interest. for ratification within an agreed ‘grace pe- The Czech Republic is the first of the riod’. This formal procedure was con- Central and East European countries to On 20 September 2006, at a meeting at cluded on 30 April 2007, when I was noti- join ESO. The membership underlines ESO Headquarters, the negotiating teams fied of the deposition of the instrument of ESO’s continuing evolution as the prime from ESO and the Czech Republic arrived ratification at the French Ministry of European organisation for astronomy, at an agreement in principle, which was Foreign Affairs.