Metallicities of the Β Cephei Stars from Low-Resolution Ultraviolet Spectra
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The Impact of Giant Stellar Outflows on Molecular Clouds
The Impact of Giant Stellar Outflows on Molecular Clouds A thesis presented by H´ector G. Arce Nazario to The Department of Astronomy in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Astronomy Harvard University Cambridge, Massachusetts October, 2001 c 2001, by H´ector G. Arce Nazario All Rights Reserved ABSTRACT Thesis Advisor: Alyssa A. Goodman Thesis by: H´ector G. Arce Nazario We use new millimeter wavelength observations to reveal the important effects that giant (parsec-scale) outflows from young stars have on their surroundings. We find that giant outflows have the potential to disrupt their host cloud, and/or drive turbulence there. In addition, our study confirms that episodicity and a time-varying ejection axis are common characteristics of giant outflows. We carried out our study by mapping, in great detail, the surrounding molecular gas and parent cloud of two giant Herbig-Haro (HH) flows; HH 300 and HH 315. Our study shows that these giant HH flows have been able to entrain large amounts of molecular gas, as the molecular outflows they have produced have masses of 4 to 7 M |which is approximately 5 to 10% of the total quiescent gas mass in their parent clouds. These outflows have injected substantial amounts of −1 momentum and kinetic energy on their parent cloud, in the order of 10 M km s and 1044 erg, respectively. We find that both molecular outflows have energies comparable to their parent clouds' turbulent and gravitationally binding energies. In addition, these outflows have been able to redistribute large amounts of their surrounding medium-density (n ∼ 103 cm−3) gas, thereby sculpting their parent cloud and affecting its density and velocity distribution at distances as large as 1 to 1.5 pc from the outflow source. -
Research and Scientific Support Department 2003 – 2004
COVER 7/11/05 4:55 PM Page 1 SP-1288 SP-1288 Research and Scientific Research Report on the activities of the Support Department Research and Scientific Support Department 2003 – 2004 Contact: ESA Publications Division c/o ESTEC, PO Box 299, 2200 AG Noordwijk, The Netherlands Tel. (31) 71 565 3400 - Fax (31) 71 565 5433 Sec1.qxd 7/11/05 5:09 PM Page 1 SP-1288 June 2005 Report on the activities of the Research and Scientific Support Department 2003 – 2004 Scientific Editor A. Gimenez Sec1.qxd 7/11/05 5:09 PM Page 2 2 ESA SP-1288 Report on the Activities of the Research and Scientific Support Department from 2003 to 2004 ISBN 92-9092-963-4 ISSN 0379-6566 Scientific Editor A. Gimenez Editor A. Wilson Published and distributed by ESA Publications Division Copyright © 2005 European Space Agency Price €30 Sec1.qxd 7/11/05 5:09 PM Page 3 3 CONTENTS 1. Introduction 5 4. Other Activities 95 1.1 Report Overview 5 4.1 Symposia and Workshops organised 95 by RSSD 1.2 The Role, Structure and Staffing of RSSD 5 and SCI-A 4.2 ESA Technology Programmes 101 1.3 Department Outlook 8 4.3 Coordination and Other Supporting 102 Activities 2. Research Activities 11 Annex 1: Manpower Deployment 107 2.1 Introduction 13 2.2 High-Energy Astrophysics 14 Annex 2: Publications 113 (separated into refereed and 2.3 Optical/UV Astrophysics 19 non-refereed literature) 2.4 Infrared/Sub-millimetre Astrophysics 22 2.5 Solar Physics 26 Annex 3: Seminars and Colloquia 149 2.6 Heliospheric Physics/Space Plasma Studies 31 2.7 Comparative Planetology and Astrobiology 35 Annex 4: Acronyms 153 2.8 Minor Bodies 39 2.9 Fundamental Physics 43 2.10 Research Activities in SCI-A 45 3. -
Early-Type Variables in the Magellanic Clouds
A&A 388, 88–99 (2002) Astronomy DOI: 10.1051/0004-6361:20020437 & c ESO 2002 Astrophysics Early-type variables in the Magellanic Clouds I. β Cephei stars in the LMC bar A. Pigulski and Z. Kolaczkowski Wroc law University Observatory, Kopernika 11, 51-622 Wroc law, Poland Received 13 February 2002 / Accepted 21 March 2002 Abstract. A thorough analysis of the OGLE-II time-series photometry of the Large Magellanic Cloud bar sup- plemented by similar data from the MACHO database led us to the discovery of three β Cephei-type stars. These are the first known extragalactic β Cephei-type stars. Two of the three stars are multiperiodic. Two stars have inferred masses of about 10 M while the third is about 2 mag brighter and at least twice as massive. All three variables are located in or very close to the massive and young LMC associations (LH 41, 59 and 81). It is therefore very probable that the variables have higher than average metallicities. This would reconcile our finding with theoretical predictions of the shape and location of the β Cephei instability strip in the H-R diagram. The low number of β Cephei stars found in the LMC is another observational confirmation of strong dependence of the mechanism driving pulsations in these variables on metallicity. Follow-up spectroscopic determination of the metallicities in the discovered variables will provide a good test for the theory of pulsational stability in massive main-sequence stars. Key words. stars: early-type – stars: oscillations – stars: variable: other – stars: abundances – Magellanic Clouds 1. -
Annual Report 2003
Deutsches Zentrum für Luft- und Raumfahrt e.V. German Aerospace Center Institute of Planetary Research SECTION: “PHYSICS OF SMALL BODIES AND EXTRA-SOLAR PLANETS” Annual Report 2003 OBSERVATIONS MODELLIN G FIREWATCH TECHNOLOGY SPACE MISSIONS http://solarsystem.dlr.de/KK 0 From left to right: First row: Detlef de Niem [email protected] Scientific staff member Dr. Alan W. Harris [email protected] Deputy section leader Dr. Anders Erikson1 [email protected] Scientific staff member Dr. Carmen Tornow [email protected] Scientific staff member Second row: Holger Voss1 [email protected] PhD student Dr. Gerhard Hahn [email protected] Scientific staff member Prof. U. Motschmann [email protected] Guest scientist Dr. Heike Rauer1 [email protected] Group leader Dr. Ekkehard Kührt [email protected] Section leader Dr. Jörg Knollenberg [email protected] Scientific staff member Rosemarie Mooseder Secretary (retired) Michael Müller [email protected] PhD student Martin Prescher Guest student Egon Braatz [email protected] Technical staff member Not appearing in the photo: Dr. Stefano Mottola [email protected] Scientific staff member Ralph Kahle [email protected] PhD student Michael Weiler 1 [email protected] PhD student Stephanie Werner [email protected] PhD student 1 Group: Extrasolar planets and cometary atmospheres 1 Contents Contents................................................................................................................................ 2 1. Introduction (E. Kührt)....................................................................................................... 3 2. Asteroid science................................................................................................................ 4 2.1 Keck thermal-infrared observations of near-Earth asteroids (A. W. Harris)..................... 4 2.2 Investigations of the physical properties of near-Earth asteroids with data from the NASA Infrared Telescope Facility (A. -
Arxiv:Astro-Ph/0611634V1 20 Nov 2006
Last edited August 28, 2006 Infrared Nebulae Around Young Stellar Objects Michael S. Connelley1 Bo Reipurth2 and Alan T. Tokunaga3 ABSTRACT We present a K-band atlas of 106 reflection nebulae, 41 of which are new discoveries. We observed these nebulae with the UH 2.2 m telescope in the course of an imaging survey of 197 objects that were selected to be nearby young Class I sources. K-band images and flux calibrated surface brightness contour plots of each nebula are presented. We found that the near-IR luminosities and physical sizes of the nebulae increase with the bolometric luminosity of the illuminating sources. Only 22 nebulae, about 10% of these candidate Class I sources, have indications of shocked H2 emission. The great variety of nebulae that we observed prevented us from classifying them based on morphology. However, we note that as the spectral index decreases, the central star is more frequently visible at K- band and the flux from the central star tends to be dominant over the flux from the nebula. For objects that have a higher spectral index, most of the K-band flux is from the reflection nebula, and the central star is less frequently visible. arXiv:astro-ph/0611634v1 20 Nov 2006 The nebula around IRAS 05450+0019 has a unique morphology, and we speculate that it may be an example of a disk shadow being projected into the surrounding cloud. We present J, H, and K-band images of this object with surface brightness contours, as well as its SED from 1.2 µm to 100 µm. -
Lists and Charts of Autostar Named Stars
APPENDIX A Lists and Charts of Autostar Named Stars Table A.I provides a list of named stars that are stored in the Autostar database. Following the list, there are constellation charts which show where the stars are located. The names are in alphabetical orderalong with their Latin designation (see Appendix B for complete list ofconstellations). Names in brackets 0 in the table denote a different spelling to one that is known in the list. The star's co-ordinates are set to the same as accuracy as the Autostar co-ordinates i.e. the RA or Dec 'sec' values are omitted. Autostar option: Select Item: Object --+ Star --+ Named 215 216 Appendix A Table A.1. Autostar Named Star List RA Dec Named Star Fig. Ref. latin Designation Hr Min Deg Min Mag Acamar A5 Theta Eridanus 2 58 .2 - 40 18 3.2 Achernar A5 Alpha Eridanus 1 37.6 - 57 14 0.4 Acrux A4 Alpha Crucis 12 26.5 - 63 05 1.3 Adara A2 EpsilonCanis Majoris 6 58.6 - 28 58 1.5 Albireo A4 BetaCygni 19 30.6 ++27 57 3.0 Alcor Al0 80 Ursae Majoris 13 25.2 + 54 59 4.0 Alcyone A9 EtaTauri 3 47.4 + 24 06 2.8 Aldebaran A9 Alpha Tauri 4 35.8 + 16 30 0.8 Alderamin A3 Alpha Cephei 21 18.5 + 62 35 2.4 Algenib A7 Gamma Pegasi 0 13.2 + 15 11 2.8 Algieba (Algeiba) A6 Gamma leonis 10 19.9 + 19 50 2.6 Algol A8 Beta Persei 3 8.1 + 40 57 2.1 Alhena A5 Gamma Geminorum 6 37.6 + 16 23 1.9 Alioth Al0 EpsilonUrsae Majoris 12 54.0 + 55 57 1.7 Alkaid Al0 Eta Ursae Majoris 13 47.5 + 49 18 1.8 Almaak (Almach) Al Gamma Andromedae 2 3.8 + 42 19 2.2 Alnair A6 Alpha Gruis 22 8.2 - 46 57 1.7 Alnath (Elnath) A9 BetaTauri 5 26.2 -
October 2020 BRAS Newsletter
A Neowise Comet 2020, photo by Ralf Rohner of Skypointer Photography Monthly Meeting October 12th at 7:00 PM, via Jitsi (Monthly meetings are on 2nd Mondays at Highland Road Park Observatory, temporarily during quarantine at meet.jit.si/BRASMeets). GUEST SPEAKER: Tom Field, President of Field Tested Systems and Contributing Editor for Sky & Telescope Magazine. His presentation is on Astronomical Spectra. What's In This Issue? President’s Message Secretary's Summary Business Meeting Minutes Outreach Report Asteroid and Comet News Light Pollution Committee Report Globe at Night Astro-Photos by BRAS Members Messages from the HRPO REMOTE DISCUSSION Solar Viewing Great Martian Opposition Uranian Opposition Lunar Halloween Party Edge of Night Observing Notes: Cepheus – The King Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society BRAS YouTube Channel Baton Rouge Astronomical Society Newsletter, Night Visions Page 2 of 27 October 2020 President’s Message Happy October. I hope everybody has been enjoying this early cool front and the taste of fall that comes with it. More to our interests, I hope everybody has been enjoying the longer evenings thanks to our entering Fall. Soon, those nights will start even earlier as Daylight Savings time finally ends for the year— unfortunately, it may be the last Standard Time for some time. Legislation passed over the summer will mandate Louisiana doing away with Standard time if federal law allows, and a bill making it’s way through the US senate right not aims to do just that: so, if you prefer earlier sunsets, take the time to write your congressmen before it’s too late. -
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A&A 551, A130 (2013) Astronomy DOI: 10.1051/0004-6361/201219010 & c ESO 2013 Astrophysics Study of a sample of faint Be stars in the exofield of CoRoT I. Spectroscopic characterization T. Semaan1,A.M.Hubert1,J.Zorec2,C.Martayan3,1,Y.Frémat4, J. Gutiérrez-Soto5,6,7, and J. Fabregat8 1 GEPI, Observatoire de Paris, CNRS UMR 8111, Université Paris Diderot, Place Jules Janssen, 92195 Meudon, France 2 Université Pierre & Marie Curie, CNRS UMR 7095, Institut d’Astrophysique de Paris, 98bis Bd. Arago, 75014 Paris, France 3 European Organization for Astronomical Research in the Southern Hemisphere, Alonso de Cordova 3107, Vitacura, Santiago de Chile, Chile 4 Royal Observatory of Belgium, 3 avenue Circulaire, 1180 Brussels, Belgium 5 Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n 18008, Granada, Spain 6 LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92195 Meudon, France 7 Universidad Internacional Valenciana − VIU, Prolongación C/ José Pradas Gallen, s/nEdificioB2◦ Piso, 12006 Castellón de la Plana, Spain 8 Observatorio Astronómico de la Universidad de Valencia, Calle Catedrático Agustín Escardino 7, 46980 Paterna, Valencia, Spain Received 10 February 2012 / Accepted 2 November 2012 ABSTRACT Context. Be stars are probably the most rapid rotators among stars in the main sequence (MS) and, as such, are excellent candidates to study the incidence of the rotation on the characteristics of their non-radial pulsations, as well as on their internal structure. Pulsations are also thought to be possible mechanisms that help the mass ejection needed to build up the circumstellar disks of Be stars. -
An Infrared Nebula Associated with # Cephei: Evidence of Mass Loss?
AN INFRARED NEBULA ASSOCIATED WITH # CEPHEI: EVIDENCE OF MASS LOSS? The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Marengo, M., N. R. Evans, P. Barmby, L. D. Matthews, G. Bono, D. L. Welch, M. Romaniello, D. Huelsman, K. Y. L. Su, and G. G. Fazio. “AN INFRARED NEBULA ASSOCIATED WITH δ CEPHEI: EVIDENCE OF MASS LOSS?” The Astrophysical Journal 725, no. 2 (December 7, 2010): 2392–2400. © 2010 The American Astronomical Society As Published http://dx.doi.org/10.1088/0004-637x/725/2/2392 Publisher IOP Publishing Version Final published version Citable link http://hdl.handle.net/1721.1/95824 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The Astrophysical Journal, 725:2392–2400, 2010 December 20 doi:10.1088/0004-637X/725/2/2392 C 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A. AN INFRARED NEBULA ASSOCIATED WITH δ CEPHEI: EVIDENCE OF MASS LOSS? M. Marengo1,N.R.Evans2, P. Barmby3, L. D. Matthews2,4,G.Bono5,6, D. L. Welch7, M. Romaniello8, D. Huelsman2,9,K.Y.L.Su10, and G. G. Fazio2 1 Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA 2 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA 3 Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 4K7, Canada 4 MIT Haystack Observatory, Off Route 40, Westford, MA 01886, USA 5 Department of Physics, Universita` di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma, Italy 6 INAF–Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone, Italy 7 Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada 8 European Southern Observatory, Karl-Schwarzschild-Street 2, 85748 Garching bei Munchen, Germany 9 Department of Physics, University of Cincinnati, P.O. -
THE STAR FORMATION NEWSLETTER an Electronic Publication Dedicated to Early Stellar Evolution and Molecular Clouds
THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar evolution and molecular clouds No. 189 — 1 Sept 2008 Editor: Bo Reipurth ([email protected]) Abstracts of recently accepted papers Binary formation and mass function variations in fragmenting discs with short cooling times R.D. Alexander1,2, P.J. Armitage2,3, & J. Cuadra2 1 Sterrewacht Leiden, Universiteit Leiden, Niels Bohrweg 2, 2300 RA, Leiden, the Netherlands 2 JILA, University of Colorado, Boulder, CO 80309-0440, USA 3 Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309-0391, USA E-mail contact: rda at strw.leidenuniv.nl Accretion discs at sub-pc distances around supermassive black holes are likely to cool rapidly enough that self-gravity results in fragmentation. Here, we use high-resolution hydrodynamic simulations of a simplified disc model to study how the outcome of fragmentation depends upon numerical resolution and cooling time, and to investigate the incidence of binary formation within fragmenting discs. We investigate a range of cooling times, from the relatively long cooling time-scales that are marginally unstable to fragmentation down to highly unstable cooling on a time-scale that is shorter than the local dynamical time. The characteristic mass of fragments decreases with reduced cooling time, though the effect is modest and dependent upon details of how rapidly bound clumps radiate. We observe a high incidence of capture binaries, though we are unable to determine their final orbits or probability of survival. The results suggest that faster cooling in the parent disc results in an increased binary fraction, and that a high primordial binary fraction may result from disc fragmentation. -
Pulsating Stars in NGC 6231 Frequency Analysis and Photometric Mode Identification Near the Main Sequence
Astronomy & Astrophysics manuscript no. Pulsating˙stars˙NGC6231 c ESO 2018 December 3, 2018 Pulsating stars in NGC 6231 Frequency analysis and photometric mode identification near the main sequence Stefan Meingast1, Gerald Handler2, and Robert R. Shobbrook3 1 Institut fur¨ Astrophysik, Universitat¨ Wien, Turkenschanzstrasse¨ 17, 1180 Wien, Austria 2 Nicolaus Copernicus Astronomical Center, Bartycka 18, 00-716, Warsaw, Poland 3 Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT, Australia ABSTRACT Aims. We used Johnson UBV photometric CCD observations to identify pulsating and other variable stars in the young open cluster NGC 6231. The multi-color information was used to classify pulsating variables, perform frequency analysis, and - where possible - to compare observed to theoretical amplitude ratios for mode identification. Methods. The CCD data were used to investigate a total of 473 stars in the field. The data reduction was performed with standard IRAF tools, where the extraction of light curves has been done with combined aperture and point-spread-function (PSF) photometry routines delivered with the DAOPHOT package. Differential light curves have been obtained by identifying a set of suitable comparison stars and the frequency analysis was then conducted on the basis of Fourier methods. Our classification of pulsating stars was based on the time scales and amplitudes of the variability with respect to the different filters and stellar parameters as calculated from published Stromgren¨ and Geneva photometry. Attempts to set constraints on the pulsation mode were performed for stars with sufficiently high amplitude based on the significant dependence of amplitudes on wavelength. Results. We identified 32 variable stars in the field of the cluster out of which 21 are confirmed members of NGC 6231 and twelve are newly detected variable stars. -
Rocznik Astronomiczny 2014
INSTYTUT GEODEZJI I KARTOGRAFII ROCZNIK ASTRONOMICZNY NA ROK 2014 LXIX WARSZAWA 2013 Redaktor naukowy Rocznika Astronomicznego Jan Kryński Sekretarz: Marcin Sękowski Adres Redakcji: Instytut Geodezji i Kartografii 02679 Warszawa, ul. Modzelewskiego 27 email: [email protected] http://www.igik.edu.pl Prenumerata: email: [email protected] Projekt okładki Łukasz Żak Przy projektowaniu okładki wykorzystano atlas nieba Jana Heweliusza JOHANNIS HEVELII, URANOGRAPHIA, TOTUM COELUM STELLATUM, 1690 reprint wydawnictwa Uzbeckiej Akademii Nauk, Taszkent, 1968 Copyright C Instytut Geodezji i Kartografii ISSN 02090341 INSTYTUT GEODEZJI I KARTOGRAFII Nakład 200 egz. Papier offsetowy kl. III. Druk ze składu komputerowego przygotowanego w ZGiG IGiK SPIS TRECI Przedmowa ................................................... ............................... 5 Skróty stosowane w Roczniku Astronomicznym .............................................. 6 Dni wiąteczne, pory roku, stałe precesyjne, obserwatoria astronomiczne ...................... 7 Czas gwiazdowy Greenwich i Kąt Obrotu Ziemi .......................................... 8 11 Słońce, współrzędne równikowe, wschody i zachody w Warszawie ........................ 12÷19 Księżyc, współrzędne równikowe, wschody i zachody w Warszawie ....................... 20÷27 Momenty wejć Słońca w znaki Zodiaku ................................................... .÷28 Planety, współrzędne równikowe ................................................... ......... 28 Fazy Księżyca, apogeum i perigeum ..................................................