The Supernova Impostor 1961V∗
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Luminous Blue Variables
Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs. -
Snhunt151: an Explosive Event Inside a Dense Cocoon
MNRAS 475, 2614–2631 (2018) doi:10.1093/mnras/sty009 Advance Access publication 2018 January 9 SNhunt151: an explosive event inside a dense cocoon N. Elias-Rosa,1,2‹ S. Benetti,1 E. Cappellaro,1 A. Pastorello,1 G. Terreran,1 A. Morales-Garoffolo,2 S. C. Howerton,3 S. Valenti,4 E. Kankare,5 A. J. Drake,6 S. G. Djorgovski,6 L. Tomasella,1 L. Tartaglia,1,7 T. Kangas,8 P. Ochner,1 Downloaded from https://academic.oup.com/mnras/article-abstract/475/2/2614/4795309 by Universidad Andres Bello user on 22 April 2019 A. V. Filippenko,9,10 F. Ciabattari,11 S. Geier,12,13 D. A. Howell,14,15 J. Isern,2 S. Leonini,16 G. Pignata17,18 and M. Turatto1 1INAF – Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, I-35122 Padova, Italy 2Department of Applied Physics, University of Cadiz,´ Campus of Puerto Real, E-11510 Cadiz,´ Spain 31401 South A, Arkansas City, KS 67005, USA 4Department of Physics, University of California, Davis, CA 95616, USA 5Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, UK 6Astronomy Department, California Institute of Technology, Pasadena, CA 91125, USA 7Department of Astronomy and Steward Observatory, University of Arizona, 933 N Cherry Ave, Tucson, AZ 85719, USA 8Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Vais¨ al¨ antie¨ 20, FI-21500 Piikkio,¨ Finland 9Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA 10Miller Senior Fellow, Miller Institute for Basic Research in Science, University of California, -
Curriculum Vitae Thomas Matheson
Curriculum Vitae Thomas Matheson Address: NSF's National Optical-Infrared Astronomy Research Laboratory Community Science and Data Center 950 North Cherry Avenue Tucson, AZ 85719, USA Telephone: (520) 318{8517 Fax: (520) 318{8360 e-mail: [email protected] WWW: http://www.noao.edu/noao/staff/matheson/ Education: University of California, Berkeley, Berkeley, CA Department of Astronomy Ph.D. received June 2000 M.A. received June 1992 PhD Thesis Topic: The Spectral Characteristics of Stripped-Envelope Supernovae Thesis Advisor: Professor Alexei V. Filippenko Harvard University, Cambridge, MA Department of Astronomy & Astrophysics and Physics A.B. magna cum laude, received June 1989 Senior Thesis Topic: Transients in the Solar Transition Region Thesis Advisor: Professor Robert W. Noyes Employment: NSF's National Optical-Infrared Astronomy Research Laboratory (The Former National Optical Astronomy Observatory) Community Science and Data Center Head of Time-Domain Services 2017 { present Astronomer 2018 { present Associate Astronomer 2009 { 2018 (Tenure, 2011) Assistant Astronomer 2004 { 2009 Harvard-Smithsonian Center for Astrophysics Optical and Infrared Division Post-doctoral fellow 2000 { 2004 University of California, Berkeley Department of Astronomy Research Assistant 1991 { 2000 Harvard-Smithsonian Center for Astrophysics Solar and Stellar Physics Division Research Assistant 1989 { 1990 Thomas Matheson|Curriculum Vitae Teaching: Harvard University, Department of Astronomy, Teaching Assistant 2001, 2003 University of California, Berkeley, -
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. -
Arxiv:1108.0403V1 [Astro-Ph.CO] 1 Aug 2011 Esitps Hleg Oglx Omto Oesadthe and Models Formation Galaxy at to Tion
Noname manuscript No. (will be inserted by the editor) Production of dust by massive stars at high redshift C. Gall · J. Hjorth · A. C. Andersen To be published in A&A Review Abstract The large amounts of dust detected in sub-millimeter galaxies and quasars at high redshift pose a challenge to galaxy formation models and theories of cosmic dust forma- tion. At z > 6 only stars of relatively high mass (> 3 M⊙) are sufficiently short-lived to be potential stellar sources of dust. This review is devoted to identifying and quantifying the most important stellar channels of rapid dust formation. We ascertain the dust production ef- ficiency of stars in the mass range 3–40 M⊙ using both observed and theoretical dust yields of evolved massive stars and supernovae (SNe) and provide analytical expressions for the dust production efficiencies in various scenarios. We also address the strong sensitivity of the total dust productivity to the initial mass function. From simple considerations, we find that, in the early Universe, high-mass (> 3 M⊙) asymptotic giant branch stars can only be −3 dominant dust producers if SNe generate . 3 × 10 M⊙ of dust whereas SNe prevail if they are more efficient. We address the challenges in inferring dust masses and star-formation rates from observations of high-redshift galaxies. We conclude that significant SN dust pro- duction at high redshift is likely required to reproduce current dust mass estimates, possibly coupled with rapid dust grain growth in the interstellar medium. C. Gall Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark Tel.: +45 353 20 519 Fax: +45 353 20 573 E-mail: [email protected] J. -
The Sitian Project
An Acad Bras Cienc (2021) 93(Suppl. 1): e20200628 DOI 10.1590/0001-3765202120200628 Anais da Academia Brasileira de Ciências | Annals of the Brazilian Academy of Sciences Printed ISSN 0001-3765 I Online ISSN 1678-2690 www.scielo.br/aabc | www.fb.com/aabcjournal PHYSICAL SCIENCES The SiTian Project JIFENG LIU, ROBERTO SORIA, XUE-FENG WU, HONG WU & ZHAOHUI SHANG Abstract: SiTian is an ambitious ground-based all-sky optical monitoring project, developed by the Chinese Academy of Sciences. The concept is an integrated network of dozens of 1-m-class telescopes deployed partly in China and partly at various other sites around the world. The main science goals are the detection, identification and monitoring of optical transients (such as gravitational wave events, fast radio bursts, supernovae) on the largely unknown timescales of less than 1 day; SiTian will also provide a treasure trove of data for studies of AGN, quasars, variable stars, planets, asteroids, and microlensing events. To achieve those goals, SiTian will scan at least 10,000 square deg of sky every 30 min, down to a detection limit of V ≈ 21 mag. The scans will produce simultaneous light-curves in 3 optical bands. In addition, SiTian will include at least three 4-m telescopes specifically allocated for follow-up spectroscopy of the most interesting targets. We plan to complete the installation of 72 telescopes by 2030 and start full scientific operations in 2032. Key words: surveys, telescopes, transients, relativistic processes. INTRODUCTION a 6.7-m filled aperture) with a 9.6 square deg field of view (Ivezić et al. -
Lecture 17 Binary Evolution Type Ib and Ic Supernovae
Lecture 17 Binary Evolution Type Ib and Ic Supernovae Half or more of massive stars are found in binaries with such close separations that the stars will interact when one of them becomes a supergiant (Sana & Evans 2011; Sana et al. 2012). [Podsiadlowski says 30 – 50%, but in any case the fraction is large] 6 Ph. Podsiadlowski Classification of Roche-lobe overflow phases See class website 5 MO (Paczynski) carbon ignition P = 4300 d R/ RO. 1000 • Case A –the star is on 45 % M = 5 M the main sequence 1 O. P is the maximum period M / M = 2 1 2 Case C below which mass radius evolution exchange of the given • Case B – the star has type will occur finished H burning but 100 helium ignition not He burning P = 87 d The rough percentage of 5 MO stars that will interact during the 45 % • Case C – post-He core given stage is indicated burning Case B 10 P = 1.5 d Case A 10 % P = 0.65 d main sequence 7 0 5 10 (10 yr) Figure 1.1 The evolution of the radius of a 5 M⊙ star as a function of its lifetime to illustrate the ranges in radius and orbital period for the different cases of RLOF phases, as indicated, assuming a2.5 2 M⊙ companion. of stars and supernovae that probe the late evolutionary phases of a star (see § 1.4). Note also that quite massive stars (∼> 20 M⊙)tendtoexpandonlymoderatelyafter helium core burning, and hence, for massive stars, Case C masstransfertendsto be much less important than Case B mass transfer, where most oftheexpansion occurs. -
Curriculum Vitae of You-Hua Chu
Curriculum Vitae of You-Hua Chu Address and Telephone Number: Institute of Astronomy and Astrophysics, Academia Sinica 11F of Astronomy-Mathematics Building, AS/NTU No.1, Sec. 4, Roosevelt Rd, Taipei 10617 Taiwan, R.O.C. Tel: (886) 02 2366 5300 E-mail address: [email protected] Academic Degrees, Granting Institutions, and Dates Granted: B.S. Physics Dept., National Taiwan University 1975 Ph.D. Astronomy Dept., University of California at Berkeley 1981 Professional Employment History: 2014 Sep - present Director, Institute of Astronomy and Astrophysics, Academia Sinica 2014 Jul - present Distinguished Research Fellow, Institute of Astronomy and Astrophysics, Academia Sinica 2014 Jul - present Professor Emerita, University of Illinois at Urbana-Champaign 2005 Aug - 2011 Jul Chair of Astronomy Dept., University of Illinois at Urbana-Champaign 1997 Aug - 2014 Jun Professor, University of Illinois at Urbana-Champaign 1992 Aug - 1997 Jul Research Associate Professor, University of Illinois at Urbana-Champaign 1987 Jan - 1992 Aug Research Assistant Professor, University of Illinois at Urbana-Champaign 1985 Feb - 1986 Dec Graduate College Scholar, University of Illinois at Urbana-Champaign 1984 Sep - 1985 Jan Lindheimer Fellow, Northwestern University 1982 May - 1984 Jun Postdoctoral Research Associate, University of Wisconsin at Madison 1981 Oct - 1982 May Postdoctoral Research Associate, University of Illinois at Urbana-Champaign 1981 Jun - 1981 Aug Postdoctoral Research Associate, University of California at Berkeley Committees Served: -
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Space Traveler 1St Wikibook!
Space Traveler 1st WikiBook! PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Fri, 25 Jan 2013 01:31:25 UTC Contents Articles Centaurus A 1 Andromeda Galaxy 7 Pleiades 20 Orion (constellation) 26 Orion Nebula 37 Eta Carinae 47 Comet Hale–Bopp 55 Alvarez hypothesis 64 References Article Sources and Contributors 67 Image Sources, Licenses and Contributors 69 Article Licenses License 71 Centaurus A 1 Centaurus A Centaurus A Centaurus A (NGC 5128) Observation data (J2000 epoch) Constellation Centaurus [1] Right ascension 13h 25m 27.6s [1] Declination -43° 01′ 09″ [1] Redshift 547 ± 5 km/s [2][1][3][4][5] Distance 10-16 Mly (3-5 Mpc) [1] [6] Type S0 pec or Ep [1] Apparent dimensions (V) 25′.7 × 20′.0 [7][8] Apparent magnitude (V) 6.84 Notable features Unusual dust lane Other designations [1] [1] [1] [9] NGC 5128, Arp 153, PGC 46957, 4U 1322-42, Caldwell 77 Centaurus A (also known as NGC 5128 or Caldwell 77) is a prominent galaxy in the constellation of Centaurus. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type (lenticular galaxy or a giant elliptical galaxy)[6] and distance (10-16 million light-years).[2][1][3][4][5] NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers.[10] The galaxy is also the fifth brightest in the sky,[10] making it an ideal amateur astronomy target,[11] although the galaxy is only visible from low northern latitudes and the southern hemisphere. -
Radiation-Driven Stellar Eruptions
galaxies Review Radiation-Driven Stellar Eruptions Kris Davidson Minnesota Institute for Astrophysics, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455, USA; [email protected]; Tel.: +1-612-624-5711 Received: 20 December 2019; Accepted: 25 January 2020; Published: 5 February 2020 Abstract: Very massive stars occasionally expel material in colossal eruptions, driven by continuum radiation pressure rather than blast waves. Some of them rival supernovae in total radiative output, and the mass loss is crucial for subsequent evolution. Some are supernova impostors, including SN precursor outbursts, while others are true SN events shrouded by material that was ejected earlier. Luminous Blue Variable stars (LBV’s) are traditionally cited in relation with giant eruptions, though this connection is not well established. After four decades of research, the fundamental causes of giant eruptions and LBV events remain elusive. This review outlines the basic relevant physics, with a brief summary of essential observational facts. Reasons are described for the spectrum and emergent radiation temperature of an opaque outflow. Proposed mechanisms are noted for instabilities in the star’s photosphere, in its iron opacity peak zones, and in its central region. Various remarks and conjectures are mentioned, some of them relatively unfamiliar in the published literature. Keywords: Eddington Limit; eruption; supernova impostor; LBV; Luminous Blue Variable; stellar outflow; strange modes; iron opacity; bistability jump; inflation 1. Super-Eddington Events in Massive Stars Very massive stars lose much—and possibly most—of their mass in sporadic events driven by continuum radiation. This fact has dire consequences for any attempt to predict the star’s evolution. -
Connecting the Progenitors, Pre-Explosion Variability and Giant Outbursts of Luminous Blue Variables with Gaia16cfr
MNRAS 473, 4805–4823 (2018) doi:10.1093/mnras/stx2675 Advance Access publication 2017 October 13 Connecting the progenitors, pre-explosion variability and giant outbursts of luminous blue variables with Gaia16cfr Charles D. Kilpatrick,1‹ Ryan J. Foley,1 Maria R. Drout,2 Yen-Chen Pan,1 Downloaded from https://academic.oup.com/mnras/article-abstract/473/4/4805/4553531 by Australian National University user on 23 December 2018 Fiona H. Panther,3,4 David A. Coulter,1 Alexei V. Filippenko,5,6† G. Howard Marion,7 Anthony L. Piro,2 Armin Rest,8 Ivo R. Seitenzahl,3,9 Giovanni Strampelli8 and Xi E. Wang3 1Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA 2Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101, USA 3Research School of Astronomy and Astrophysics, Australian National University, Canberra, 2611, Australia 4ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO) 5Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA 6Miller Institute for Basic Research in Science, University of California, Berkeley, CA 94720, USA 7Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259, USA 8Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 9School of Physical, Environmental, and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia Accepted 2017 October 10. Received 2017 September 11; in original form 2017 June 29 ABSTRACT We present multi-epoch, multicolour pre-outburst photometry and post-outburst light curves and spectra of the luminous blue variable (LBV) outburst Gaia16cfr discovered by the Gaia satellite on 2016 December 1 UT.