The Red Supergiant Content of the Local Group
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THE MAGELLANIC CLOUDS NEWSLETTER an Electronic Publication Dedicated to the Magellanic Clouds, and Astrophysical Phenomena Therein
THE MAGELLANIC CLOUDS NEWSLETTER An electronic publication dedicated to the Magellanic Clouds, and astrophysical phenomena therein No. 85 | 1 February 2007 http://www.astro.keele.ac.uk/MCnews Editors: Jacco van Loon and Sne·zana Stanimirovi¶c Editorial Dear Colleagues, It is our pleasure to present the 85th issue of the Magellanic Clouds Newsletter. Two very interesting contributions discuss the tidal e®ects on the Magellanic Clouds, creating the Magellanic Bridge (Harris) and causing tidal heating of the disk of the LMC (Olsen & Massey). Several other contributions shed new light on the late stages of stellar evolution from studies in the Magellanic Clouds There are two job announcements, one for a postdoctoral fellowship and another one for PhD studentships. And you might well be interested in the release of shape, a powerful tool for interpreting position-velocity datacubes. The next issue will be distributed on the 1st of April; the deadline for contributions is the 31st of March. Editorially Yours, Jacco van Loon and Sne·zana Stanimirovi¶c 1 Refereed Journal Papers Con¯rmation of New Planetary Nebulae in the Large Magellanic Cloud Richard A. Shaw1, Warren A. Reid2;3 and Quentin A. Parker2;3 1National Optical Astronomy Observatory 2Department of Physics, Macquarie University, Sydney, NSW 2109, Australia 3Anglo-Australian Observatory, PO Box 296, Epping, NSW 1710, Australia We present Hubble Space Telescope (HST) images of new planetary nebulae (PNe) that were discovered in the Reid- Parker AAO/UKST H® survey of the Large Magellanic Cloud. These serendipitous observations from various HST programs yield independent con¯rmations of 6 PNe; one other detected nebula may also be a PN, and one appears to be a region of di®use emission. -
POSTERS SESSION I: Atmospheres of Massive Stars
Abstracts of Posters 25 POSTERS (Grouped by sessions in alphabetical order by first author) SESSION I: Atmospheres of Massive Stars I-1. Pulsational Seeding of Structure in a Line-Driven Stellar Wind Nurdan Anilmis & Stan Owocki, University of Delaware Massive stars often exhibit signatures of radial or non-radial pulsation, and in principal these can play a key role in seeding structure in their radiatively driven stellar wind. We have been carrying out time-dependent hydrodynamical simulations of such winds with time-variable surface brightness and lower boundary condi- tions that are intended to mimic the forms expected from stellar pulsation. We present sample results for a strong radial pulsation, using also an SEI (Sobolev with Exact Integration) line-transfer code to derive characteristic line-profile signatures of the resulting wind structure. Future work will compare these with observed signatures in a variety of specific stars known to be radial and non-radial pulsators. I-2. Wind and Photospheric Variability in Late-B Supergiants Matt Austin, University College London (UCL); Nevyana Markova, National Astronomical Observatory, Bulgaria; Raman Prinja, UCL There is currently a growing realisation that the time-variable properties of massive stars can have a funda- mental influence in the determination of key parameters. Specifically, the fact that the winds may be highly clumped and structured can lead to significant downward revision in the mass-loss rates of OB stars. While wind clumping is generally well studied in O-type stars, it is by contrast poorly understood in B stars. In this study we present the analysis of optical data of the B8 Iae star HD 199478. -
THE AGB NEWSLETTER an Electronic Publication Dedicated to Asymptotic Giant Branch Stars and Related Phenomena
THE AGB NEWSLETTER An electronic publication dedicated to Asymptotic Giant Branch stars and related phenomena No. 117 | 1 February 2007 http://www.astro.keele.ac.uk/AGBnews Editors: Jacco van Loon and Albert Zijlstra Editorial Dear Colleagues, It is our pleasure to present you the 117th issue of the AGB Newsletter. Of the 21 refereed journal publications, eight deal directly with Planetary Nebulae | which may have something to do with planets after all, and perhaps with dark energy as well (see the contribution by Gibson & Schild). Don't miss the many job advertisements, both for PhD studentships (Denver, Vienna, Portsmouth) and postdoctoral fellowships (Vienna, Keele). The Food for Thought statement published last month generated some reaction. One of you considered the relation between rotation rate and magnetic activity to be the principal question in relation to AGB stars that needs to be answered. Hence, we make it this month's Food for Thought statement. Reactions to this, or suggestions for other pertinent questions, are very welcome and will be discussed in future issues of the newsletter. The next issue will be distributed on the 1st of March; the deadline for contributions is the 28th of February. Editorially Yours, Jacco van Loon and Albert Zijlstra Food for Thought This month's thought-provoking statement is: The relation between rotation rate and magnetic activity is the principal question in relation to AGB stars that needs to be answered Reactions to this statement or suggestions for next month's statement can be e-mailed to [email protected] (please state whether you wish to remain anonymous) 1 Refereed Journal Papers Magnetic ¯elds in planetary nebulae and post-AGB nebulae. -
The Luminosities of Cool Supergiants in the Magellanic Clouds, and the Humphreys-Davidson Limit Revisited
This is a repository copy of The luminosities of cool supergiants in the Magellanic Clouds, and the Humphreys-Davidson limit revisited. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/130065/ Version: Accepted Version Article: Davies, B., Crowther, P.A. and Beasor, E.R. (2018) The luminosities of cool supergiants in the Magellanic Clouds, and the Humphreys-Davidson limit revisited. Monthly Notices of the Royal Astronomical Society, 478 (3). pp. 3138-3148. ISSN 0035-8711 https://doi.org/10.1093/mnras/sty1302 This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Ben Davies, Paul A Crowther, Emma R Beasor, The luminosities of cool supergiants in the Magellanic Clouds, and the Humphreys–Davidson limit revisited, Monthly Notices of the Royal Astronomical Society, Volume 478, Issue 3, August 2018, Pages 3138–3148, is available online at: https://doi.org/10.1093/mnras/sty1302 Reuse Items deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. -
Thomas J. Maccarone Texas Tech
Thomas J. Maccarone PERSONAL Born August 26, 1974, Haverhill, Massachusetts, USA INFORMATION US Citizen CONTACT Department of Physics & Astronomy Voice: +1-806-742-3778 INFORMATION Texas Tech University Lubbock TX 79409 E-mail: [email protected] RESEARCH Compact object populations, especially in globular clusters; accretion and ejection physics; time INTERESTS series analysis methodology PROFESSIONAL Texas Tech University EXPERIENCE Lubbock, Texas Presidential Research Excellence Professor, Department of Physics & Astronomy August 2018-present Professor, Department of Physics & Astronomy August 2017- August 2018 Associate Professor, Department of Physics January 2013 - August 2017 University of Southampton Southampton, UK Lecturer, then Reader, School of Physics and Astronomy July 2005-December 2012 University of Amsterdam Amsterdam, The Netherlands Postdoctoral researcher May 2003 - June 2005 SISSA (Scuola Internazionale di Studi Avanazti/International School for Advanced Studies) Trieste, Italy Postdoctoral researcher November 2001 - April 2003 Yale University New Haven, Connecticut USA Research Assistant May 1997 - August 2001 Jet Propulsion Laboratory Pasadena, California USA Summer Undergraduate Research Fellow June 1994 - August 1994 EDUCATION Yale University, New Haven, CT USA Department of Astronomy Ph.D., December 2001 Dissertation Title: “Constraints on Black Hole Emission Mechanisms” Advisor: Paolo S. Coppi M.S., M.Phil., Astronomy, May 1999 California Institute of Technology, Pasadena, California USA B.S., Physics, June, 1996 HONORS AND Integrated Scholar, Designation from Texas Tech for faculty who integrate teaching, research and AWARDS service activities together, 2020 Professor of the Year Award, Texas Tech Society of Physics Students, 2017, 2019 Dirk Brouwer Prize from Yale University for “a contribution of unusual merit to any branch of astronomy,” 2003 Harry A. -
A New Survey of Cool Supergiants in the Magellanic Clouds⋆
A&A 578, A3 (2015) Astronomy DOI: 10.1051/0004-6361/201425362 & c ESO 2015 Astrophysics A new survey of cool supergiants in the Magellanic Clouds? Carlos González-Fernández1, Ricardo Dorda2, Ignacio Negueruela2, and Amparo Marco2 1 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK e-mail: [email protected] 2 Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain Received 18 November 2014 / Accepted 31 March 2015 ABSTRACT Aims. In this study we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. Methods. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership in the clouds. Results. Around two hundred new red supergiants have been detected, hinting at a yet to be observed large population. Using near- and mid-infrared photometry we study the brightness distribution of these stars, the onset of mass-loss, and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid- and near-infrared photometry to improve the observational efficiency of similar programs to this. Key words. supergiants – stars: massive – stars: late-type – stars: AGB and post-AGB – Magellanic Clouds – surveys 1. -
THE PROGENITORS of TYPE IIP SUPERNOVAE Emma R. Beasor
THE PROGENITORS OF TYPE IIP SUPERNOVAE Emma R. Beasor A thesis submitted in partial fulfilment of the requirements of Liverpool John Moores University for the degree of Doctor of Philosophy. April 2019 Declaration The work presented in this thesis was carried out at the Astrophysics Research Insti- tute, Liverpool John Moores University. Unless otherwise stated, it is the original work of the author. While registered as a candidate for the degree of Doctor of Philosophy, for which sub- mission is now made, the author has not been registered as a candidate for any other award. This thesis has not been submitted in whole, or in part, for any other degree. Emma R. Beasor Astrophysics Research Institute Liverpool John Moores University IC2, Liverpool Science Park 146 Brownlow Hill Liverpool L3 5RF UK ii Abstract Mass-loss prior to core collapse is arguably the most important factor affecting the evolution of a massive star across the Hertzsprung-Russel (HR) diagram, making it the key to understanding what mass-range of stars produce supernova (SN), and how these explosions will appear. It is thought that most of the mass-loss occurs during the red supergiant (RSG) phase, when strong winds dictate the onward evolutionary path of the star and potentially remove the entire H-rich envelope. Uncertainty in the driving mechanism for RSG winds means the mass-loss rate (M_ ) cannot be determined from first principles, and instead, stellar evolution models rely on empirical recipes to inform their calculations. At present, the most commonly used M_ -prescription comes from a literature study, whereby many measurements of mass- loss were compiled. -
HV 11423: the Coolest Supergiant in The
HV 11423: The Coolest Supergiant in the SMC Philip Massey,1,2 Emily M. Levesque,2,3 K. A. G. Olsen,4 Bertrand Plez,5 B. A. Skiff 1 ABSTRACT We call attention to the fact that one of the brightest red supergiants in the SMC has recently changed its spectral type from K0-1 I (December 2004) to M4 I (December 2005) and back to K0-1 I (September 2006). An archival spectrum from the Very Large Telescope reveals that the star was even cooler (M4.5-M5 I) in December 2001. By contrast, the star was observed to be an M0 I in both October 1978 and October 1979. The M4-5 I spectral types is by far the latest type seen for an SMC supergiant, and its temperature in that state places it well beyond the Hayashi limit into a region of the H-R diagram where the star should not be in hydrostatic equilibrium. The star is variable by nearly 2 mag in V , but essentially constant in K. Our modeling of its spectral energy distribution shows that the visual extinction has varied during this time, but that the star has remained essentially constant in bolometric luminosity. We suggest that the star is currently undergoing a period of intense instability, with its effective temperature changing from 4300 K to 3300 K on the time-scale of months. It has one of the highest 12µm fluxes of any RSG in the SMC, and we suggest that the variability at V is due primarily to changes in effective temperature, and secondly, due to changes in the local extinction due to creation and dissipation of circumstellar dust. -
A Critical Re-Evaluation of the Thorne-\. Zytkow Object Candidate HV 2112
MNRAS 000, 1–5 (2018) Preprint 2 July 2018 Compiled using MNRAS LATEX style file v3.0 A critical re-evaluation of the Thorne-Zytkow˙ object candidate HV 2112 Emma R. Beasor1⋆, Ben Davies1, Ivan Cabrera-Ziri2†, & Georgia Hurst1 1Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF, UK 2Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA Accepted XXX. Received YYY; in original form ZZZ ABSTRACT It has been argued in the literature that the star HV 2112 in the Small Magellanic Cloud is the first known example of a TZO,˙ a Red Supergiant with a degenerate neu- tron core. This claim is based on the star having a high luminosity (log(L/L⊙)∼> 5), an extremely cool effective temperature, and a surface enriched in in lithium, calcium and various irp-process elements. In this paper we re-examine this evidence, and present new measurements of the stellar properties. By compiling archival photometry from blue to mid-IR for HV 2112 and integrating under its spectral energy distribution we find a bolometric luminosity in the range of log(L/L⊙)=4.70-4.91, lower than that found in previous work and comparable to bright asymptotic giant branch (AGB) stars. We compare a VLT+XSHOOTER spectrum of HV 2112 to other late type, lu- minous SMC stars, finding no evidence for enhancements in Rb, Ca or K, though there does seem to be an enrichment in Li. We therefore conclude that a much more likely explanation for HV 2112 is that it is an intermediate mass(∼5M⊙) AGB star. -
Annual Report 2007 ESO
ESO European Organisation for Astronomical Research in the Southern Hemisphere Annual Report 2007 ESO European Organisation for Astronomical Research in the Southern Hemisphere Annual Report 2007 presented to the Council by the Director General Prof. Tim de Zeeuw ESO is the pre-eminent intergovernmental science and technology organisation in the field of ground-based astronomy. It is supported by 13 countries: Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Further coun- tries have expressed interest in member- ship. Created in 1962, ESO provides state-of- the-art research facilities to European as- tronomers. In pursuit of this task, ESO’s activities cover a wide spectrum including the design and construction of world- class ground-based observational facili- ties for the member-state scientists, large telescope projects, design of inno- vative scientific instruments, developing new and advanced technologies, further- La Silla. ing European cooperation and carrying out European educational programmes. One of the most exciting features of the In 2007, about 1900 proposals were VLT is the possibility to use it as a giant made for the use of ESO telescopes and ESO operates the La Silla Paranal Ob- optical interferometer (VLT Interferometer more than 700 peer-reviewed papers servatory at several sites in the Atacama or VLTI). This is done by combining the based on data from ESO telescopes were Desert region of Chile. The first site is light from several of the telescopes, al- published. La Silla, a 2 400 m high mountain 600 km lowing astronomers to observe up to north of Santiago de Chile. -
The Universe Contents 3 HD 149026 B
History . 64 Antarctica . 136 Utopia Planitia . 209 Umbriel . 286 Comets . 338 In Popular Culture . 66 Great Barrier Reef . 138 Vastitas Borealis . 210 Oberon . 287 Borrelly . 340 The Amazon Rainforest . 140 Titania . 288 C/1861 G1 Thatcher . 341 Universe Mercury . 68 Ngorongoro Conservation Jupiter . 212 Shepherd Moons . 289 Churyamov- Orientation . 72 Area . 142 Orientation . 216 Gerasimenko . 342 Contents Magnetosphere . 73 Great Wall of China . 144 Atmosphere . .217 Neptune . 290 Hale-Bopp . 343 History . 74 History . 218 Orientation . 294 y Halle . 344 BepiColombo Mission . 76 The Moon . 146 Great Red Spot . 222 Magnetosphere . 295 Hartley 2 . 345 In Popular Culture . 77 Orientation . 150 Ring System . 224 History . 296 ONIS . 346 Caloris Planitia . 79 History . 152 Surface . 225 In Popular Culture . 299 ’Oumuamua . 347 In Popular Culture . 156 Shoemaker-Levy 9 . 348 Foreword . 6 Pantheon Fossae . 80 Clouds . 226 Surface/Atmosphere 301 Raditladi Basin . 81 Apollo 11 . 158 Oceans . 227 s Ring . 302 Swift-Tuttle . 349 Orbital Gateway . 160 Tempel 1 . 350 Introduction to the Rachmaninoff Crater . 82 Magnetosphere . 228 Proteus . 303 Universe . 8 Caloris Montes . 83 Lunar Eclipses . .161 Juno Mission . 230 Triton . 304 Tempel-Tuttle . 351 Scale of the Universe . 10 Sea of Tranquility . 163 Io . 232 Nereid . 306 Wild 2 . 352 Modern Observing Venus . 84 South Pole-Aitken Europa . 234 Other Moons . 308 Crater . 164 Methods . .12 Orientation . 88 Ganymede . 236 Oort Cloud . 353 Copernicus Crater . 165 Today’s Telescopes . 14. Atmosphere . 90 Callisto . 238 Non-Planetary Solar System Montes Apenninus . 166 How to Use This Book 16 History . 91 Objects . 310 Exoplanets . 354 Oceanus Procellarum .167 Naming Conventions . 18 In Popular Culture . -
Late-Type Red Supergiants: Too Cool for the Magellanic Clouds?
Late-Type Red Supergiants: Too Cool for the Magellanic Clouds? Emily M. Levesque1 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 [email protected] Philip Massey1 Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 [email protected] K. A. G. Olsen Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena, Chile [email protected] Bertrand Plez GRAAL, Universite Montpellier II, CNRS, 34095 Montpellier, France [email protected] ABSTRACT We have identified seven red supergiants (RSGs) in the Large Magellanic Cloud (LMC) and four RSGs in the Small Magellanic Cloud (SMC), all of which arXiv:0705.3431v1 [astro-ph] 23 May 2007 have spectral types that are considerably later than the average type observed in their parent galaxy. Using moderate-resolution optical spectrophotometry and the MARCS stellar atmosphere models, we determine their physical properties and place them on the H-R diagram for comparison with the predictions of current stellar evolutionary tracks. The radial velocities of these stars suggest that they are likely all members of the Clouds rather than foreground dwarfs or halo giants. Their locations in the H-R diagram also show us that these stars are cooler than 1Visiting Astronomer, Cerro Tololo Inter-American Observatory (CTIO), National Optical Astronomy Observatory (NOAO), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation (NSF). –2– the current evolutionary tracks allow, appearing to the right of the Hayashi limit, a region in which stars are no longer in hydrodynamic equilibrium.