Variable Millimetre Radiation from the Colliding-Wind Binary Cygnus OB2 #8A? R
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Megahertz Emission of Massive Early-Type Stars in the Cygnus Region
Publications of the Astronomical Society of Australia (PASA) doi: 10.1017/pas.2020.xxx. Megahertz emission of massive early-type stars in the Cygnus region P. Benaglia1,2, M. De Becker3, C. H. Ishwara-Chandra4, H. Intema5,6 and N. L. Isequilla2 1Instituto Argentino de Radioastronomia, CONICET & CICPBA, CC5 (1897) Villa Elisa, Prov. de Buenos Aires, Argentina 2Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque s/n, (1900) La Plata, Argentina 3Space sciences, Technologies and Astrophysics Research (STAR) Institute, University of Liège, Quartier Agora, 19c, Allée du 6 Août, B5c, B-4000 Sart Tilman, Belgium 4National Centre for Radio Astrophysics (NCRA-TIFR), Pune, 411 007, India 5International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102, Australia 6Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, the Netherlands Abstract Massive, early type stars have been detected as radio sources for many decades. Their thermal winds radiate free-free continuum and in binary systems hosting a colliding-wind region, non-thermal emission has also been detected. To date, the most abundant data have been collected from frequencies higher than 1 GHz. We present here the results obtained from observations at 325 and 610 MHz, carried out with the Giant Metrewave Radio Telescope, of all known Wolf-Rayet and O-type stars encompassed in area of ∼15 sq degrees centred on the Cygnus region. We report on the detection of 11 massive stars, including both Wolf-Rayet and O-type systems. The measured flux densities at decimeter wavelengths allowed us to study the radio spectrum of the binary systems and to propose a consistent interpretation in terms of physical processes affecting the wide-band radio emission from these objects. -
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. -
Optical Interferometry in Astronomy
Home Search Collections Journals About Contact us My IOPscience Optical interferometry in astronomy This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2003 Rep. Prog. Phys. 66 789 (http://iopscience.iop.org/0034-4885/66/5/203) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 128.196.208.1 The article was downloaded on 18/08/2010 at 17:12 Please note that terms and conditions apply. INSTITUTE OF PHYSICS PUBLISHING REPORTS ON PROGRESS IN PHYSICS Rep. Prog. Phys. 66 (2003) 789–857 PII: S0034-4885(03)90003-0 Optical interferometry in astronomy John D Monnier University of Michigan Astronomy Department, 941 Dennison Building, 500 Church Street, Ann Arbor, MI 48109, USA E-mail: [email protected] Received 22 January 2003, in final form 24 March 2003 Published 25 April 2003 Online at stacks.iop.org/RoPP/66/789 Abstract Here I review the current state of the field of optical stellar interferometry, concentrating on ground-based work although a brief report of space interferometry missions is included. We pause both to reflect on decades of immense progress in the field as well as to prepare for a new generation of large interferometers just now being commissioned (most notably, the CHARA, Keck and VLT Interferometers). First, this review summarizes the basic principles behind stellar interferometry needed by the lay-physicist and general astronomer to understand the scientific potential as well as technical challenges of interferometry. Next, the basic design principles of practical interferometers are discussed, using the experience of past and existing facilities to illustrate important points. -
Molecular Remnant of Nova 1670 (CK Vulpeculae) I
Astronomy & Astrophysics manuscript no. CKVulMoleculesALMA_v0 c ESO 2020 June 19, 2020 Molecular remnant of Nova 1670 (CK Vulpeculae) I. Properties of the gas and its enigmatic origin Tomek Kaminski´ 1; 2, Karl M. Menten3, Romuald Tylenda1, Ka Tat Wong (Ã嘉T)3; 4, Arnaud Belloche3, Andrea Mehner5, Mirek R. Schmidt1, and Nimesh A. Patel2 1 Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Rabianska´ 8, 87-100 Torun,´ e-mail: [email protected] 2 Center for Astrophysics j Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138 3 Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany 4 Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 Saint-Martin-d’Hères, France 5 ESO – European Organisation for Astronomical Research in the Southern Hemisphere, Alonso de Cordoba 3107, Vitacura, Santiago, Chile June 19, 2020 ABSTRACT CK Vul erupted in 1670 and is considered a Galactic stellar-merger candidate. Its remnant, observed 350 yr after the eruption, contains a molecular component of surprisingly rich composition, including polyatomic molecules as complex as methylamine (CH3NH2). We present interferometric line surveys with subarcsec resolution with ALMA and SMA. The observations provide interferometric maps of molecular line emission at frequencies between 88 and 243 GHz that allow imaging spectroscopy of more than 180 transitions of 26 species. We present, classify, and analyze the different morphologies of the emission regions displayed by the molecules. We also perform a non-LTE radiative-transfer analysis of emission of most of the observed species, deriving the kinetic temperatures and column densities in five parts of the molecular nebula. -
Tabetha Boyajian's CV
Dr. Tabetha Boyajian Yale University, Department of Astronomy, 52 Hillhouse Ave., New Haven, CT 06520 USA [email protected] • +1 (404) 849-4848 • http://www.astro.yale.edu/tabetha PROFESSIONAL Yale University, Department of Astronomy, New Haven, Connecticut, USA EXPERIENCE Postdoctoral Fellow 2012 – present • Supervisor: Dr. Debra Fischer Center for high Angular Resolution Astronomy (CHARA), Georgia State University Hubble Fellow 2009 – 2012 • Supervisor: Dr. Harold McAlister EDUCATION Georgia State University, Department of Physics and Astronomy, Atlanta, Georgia, USA Doctor of Philosophy (Ph.D.) in Astronomy 2005 – 2009 • Adviser: Dr. Harold McAlister Master of Science (M.S.) in Physics 2003 – 2005 • Adviser: Dr. Douglas Gies College of Charleston, Charleston, South Carolina, USA Bachelor of Science (B.S.) in Physics with concentration in astronomy 1998 – 2003 • Graduated with Departmental Honors PROFESSIONAL Secretary, International Astronomical Union, Division G 2015 – 2018 SERVICE Steering Committee, International Astronomical Union, Division G 2015 – 2018 Review panel member NASA Kepler Guest Observer program, NASA K2 Guest Observer program, NSF-AAG program Referee The Astronomical Journal, Astronomy & Astrophysics, PASA Telescope time allocation committee member CHARA, OPTICON (external) AREAS OF Fundamental properties of stars: diameters, temperatures, exoplanet detection and characterization, SPECIALIZATION Optical/IR interferometry, stellar spectroscopy (radial velocities, abundances, activity), absolute AND INTEREST -
ASTRONOMY and ASTROPHYSICS CO Band Emission from MWC 349 I
Astron. Astrophys. 362, 158–168 (2000) ASTRONOMY AND ASTROPHYSICS CO band emission from MWC 349 I. First overtone bands from a disk or from a wind? M. Kraus1,E.Krugel¨ 1, C. Thum2, and T.R. Geballe3 1 Max-Planck-Institut fur¨ Radioastronomie, Auf dem Hugel¨ 69, 53121 Bonn, Germany 2 Institut de Radio Astronomie Millimetrique, 38406 Saint Martin d’Heres,` France 3 Gemini Observatory, 670 North A’ohoku Place, University Park, Hilo, HI 96720, USA Received 16 December 1999 / Accepted 26 July 2000 Abstract. We have obtained spectra in the K band of the pecu- (Carr 1989; Chandler et al. 1995). The disk model is especially liar B[e]-star MWC 349. A 1.85–2.50 µm spectrum, measured supported by high resolution spectroscopic observations of the at medium resolution, contains besides the strong IR contin- CO 2 → 0 band head. For several young stellar objects the shape uum the first overtone CO bands, the hydrogen recombination of this band head shows the kinematic signature of Keplerian lines of the Pfund series, and a number of other neutral atomic rotation (Carr et al. 1993; Carr 1995; Najita et al. 1996) and is a lines and ionic lines of low ionization, all in emission. Por- powerful tracer for the existence of a circumstellar disk around tions of the CO band and superposed Pfund series lines were YSOs. observed at resolutions of 10–15 km s−1. The Pfund lines have The peculiar B[e]-star MWC 349 also shows the first over- gaussian profiles with FWHMs of ∼ 100 km s−1, are optically tone CO bands in emission, first observed by Geballe & Persson thin, and are emitted in LTE. -
Shells Around Stars F.M.Olnon
SHELLS AROUND STARS F.M.OLNON Stellingen behorende bij hec proefschrift van F.M. Olnon !. De stelling van Purton dat de uitgebreidheid van de mantels rond Be sterren bepalend is voor het al dan niet waarneembaar zijn van radiostraling is onvolledig. Purton, C.R. 1976, I.A.U. Symp. No. 60. n. 157, ed. A. Slettebak 2. Hjellming en Uade konkludeerdea ten onrechte dat de 2.7 GHz radiostraling van het Antare?-systeem geassocieerd is met de vroeg-type begeleider. Hjellming, R.M., Wade, C.M, 1971, Astrophys. J. Letters 168» LI 15 .;. Bij de berekeningen van het snelheidsveld in circumstellaire mantels die door stralingsdruk op de stofdeeltjes worden vo.-rtgedreven, mogen de effekten van optische diepte niet verwaarloosd worden. 4. Het feit dat het bijna vijf jaar heeft geduurd voordat men besefte dat maseremissie uit de achterkant van een expande- rende schil niet noemenswaardig verduisterd wordt door de sterschijf, is tekenend voor het gebrek aan inzicht bij de studie van stellaire masers. 5. Intensieve studie van de tijdsvariaties van stellaire masers levert meer zinvolle informatie over de ruimtelijke struktuur van deze maserbronnen dan VLBI metingen. 6. Bij de studie van mantels rond laat-type reuzen en de daarmee l'.enssoc i eerde maseremi ssie lieeft men Ce snel zijn toevlucht genomen tot numerieke berekeningsmethoden. 7. De snelle groei van de wnarnemingsfaci1iteiten en de vee] minder snelle toename van het annt.il aktieve astronomen leiden ertoe dat de waarnemingsresultaten steeds minder grondig worden geanalyseerd en dat nieuwe waarneenrorop.rnmnia' s steeds minder efficiënt worden opgezet. 8. Vergelijkend warenonderzoek stelt de konsument in staat om het relatief beste produkt te kopen. -
Water in the Envelopes and Disks Around Young High-Mass Stars
Astronomy & Astrophysics manuscript no. 3937 December 17, 2018 (DOI: will be inserted by hand later) Water in the envelopes and disks around young high-mass stars F. F. S. van der Tak1, C. M. Walmsley2, F. Herpin3, and C. Ceccarelli4 1 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, 53121 Bonn, Germany; e-mail: [email protected] 2 Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy 3 Observatoire de Bordeaux, L3AB, UMR 5804, B.P. 89, 33270 Floirac, France 4 Laboratoire Astrophysique de l’Observatoire de Grenoble, BP 53, 38041 Grenoble, France Received 28 July 2005 / Accepted 21 October 2005 18 Abstract. Single-dish spectra and interferometric maps of (sub-)millimeter lines of H2 O and HDO are used to study the chemistry of water in eight regions of high-mass star formation. The spectra indicate HDO excitation temperatures of ∼110 K and column densities in an 11′′ beam of ∼2×1014 cm−2 for HDO and ∼2×1017 cm−2 for H2O, with the N(HDO)/N(H2O) ratio increasing with decreasing temperature. Simultaneous observations of CH3OH and SO2 indicate that 20 – 50% of the single-dish line flux arises in the molecular outflows of these 18 objects. The outflow contribution to the H2 O and HDO emission is estimated to be 10 – 20%. Radiative transfer models indicate that the water abundance is low (∼10−6) outside a critical radius corresponding to a temperature −4 in the protostellar envelope of ≈100 K, and ‘jumps’ to H2O/H2∼10 inside this radius. -