The Physical Properties and Effective Temperature Scale of O-Type Stars As a Function of Metallicity. II. Analysis of 20 More Ma
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The VLT-FLAMES Tarantula Survey
Astronomy & Astrophysics manuscript no. msOrevfinalcorr c ESO 2019 May 8, 2019 The VLT-FLAMES Tarantula Survey XIV. The O-Type Stellar Content of 30 Doradus N. R. Walborn1, H. Sana1,2, S. Sim´on-D´ıaz3,4, J. Ma´ız Apell´aniz5, W. D. Taylor6,7, C. J. Evans7, N. Markova8, D. J. Lennon9, and A. de Koter2,10 1 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 2 Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ, Amsterdam, The Netherlands 3 Instituto de Astrof´ısica de Canarias, E-38200 La Laguna, Tenerife, Spain 4 Departamento de Astrof´ısica, Universidad de La Laguna, E-38205 La Laguna, Tenerife, Spain 5 Instituto de Astrof´ısica de Andaluc´ıa-CSIC, Glorieta de la Astronom´ıa s/n, E-18008 Granada, Spain 6 Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK 7 UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK 8 Institute of Astronomy, National Astronomical Observatory, Bulgarian Academy of Sciences, PO Box 136, 4700 Smoljan, Bulgaria 9 European Space Agency, European Space Astronomy Centre, Camino Bajo del Castillo s/n, Urbanizaci´on Villafranca del Castillo, E-28691 Villanueva de la Ca˜nada, Madrid, Spain 10 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium ABSTRACT Detailed spectral classifications are presented for 352 O–B0 stars in the VLT-FLAMES Tarantula Survey ESO Large Programme, of which 213 O-type are judged of sufficiently high quality for further morphological analysis. -
2Df-Aaomega Spectroscopy of Massive Stars in the Magellanic Clouds the North-Eastern Region of the Large Magellanic Cloud?,??
A&A 584, A5 (2015) Astronomy DOI: 10.1051/0004-6361/201525882 & c ESO 2015 Astrophysics 2dF-AAOmega spectroscopy of massive stars in the Magellanic Clouds The north-eastern region of the Large Magellanic Cloud?;?? C. J. Evans1, J. Th. van Loon2, R. Hainich3, and M. Bailey4;2 1 UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK e-mail: [email protected] 2 Astrophysics Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, ST5 5BG, UK 3 Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany 4 Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park ic2, 146 Brownlow Hill, Liverpool L3 5RF, UK Received 13 February 2015 / Accepted 5 August 2015 ABSTRACT We present spectral classifications from optical spectroscopy of 263 massive stars in the north-eastern region of the Large Magellanic Cloud. The observed two-degree field includes the massive 30 Doradus star-forming region, the environs of SN1987A, and a number of star-forming complexes to the south of 30 Dor. These are the first classifications for the majority (203) of the stars and include eleven double-lined spectroscopic binaries. The sample also includes the first examples of early OC-type spectra (AAΩ 30 Dor 248 and 280), distinguished by the weakness of their nitrogen spectra and by C IV λ4658 emission. We propose that these stars have relatively unprocessed CNO abundances compared to morphologically normal O-type stars, indicative of an earlier evolutionary phase. From analysis of observations obtained on two consecutive nights, we present radial-velocity estimates for 233 stars, finding one apparent single-lined binary and nine (>3σ) outliers compared to the systemic velocity; the latter objects could be runaway stars or large-amplitude binary systems and further spectroscopy is required to investigate their nature. -
Massive Runaway Stars in the Large Magellanic Cloud Sive (O2-Type) Stars Is Located at 100 200 Pc in Projection Table 1
Astronomy & Astrophysics manuscript no. LMC2 c ESO 2018 October 14, 2018 Massive runaway stars in the Large Magellanic Cloud V.V. Gvaramadze1,2,3, P. Kroupa1, and J. Pflamm-Altenburg1 1 Argelander-Institut f¨ur Astronomie, Universit¨at Bonn, Auf dem H¨ugel 73, 53121 Bonn, Germany e-mail: [email protected] (PK); [email protected] (JP-A) 2 Sternberg Astronomical Institute, Moscow State University, Universitetskij Pr. 13, Moscow 119992, Russia e-mail: [email protected] (VVG) 3 Isaac Newton Institute of Chile, Moscow Branch, Universitetskij Pr. 13, Moscow 119992, Russia Received 27 April 2010/ Accepted 26 May 2010 ABSTRACT The origin of massive field stars in the Large Magellanic Cloud (LMC) has long been an enigma. The recent measurements of large 1 offsets ( 100 km s− ) between the heliocentric radial velocities of some very massive (O2-type) field stars and the systemic LMC velocity∼ provides a possible explanation of this enigma and suggests that the field stars are runaway stars ejected from their birthplaces at the very beginning of their parent cluster’s dynamical evolution. A straightforward way to prove this explanation is to measure the proper motions of the field stars and to show that they are moving away from one of the nearby star clusters or OB associations. This approach is, however, complicated by the long distance to the LMC, which makes accurate proper motion measurements difficult. We used an alternative approach for solving the problem (first applied for Galactic field stars), based on the search for bow shocks produced by runaway stars. -
The R136 Star Cluster Dissected with Hubble Space Telescope/STIS
MNRAS 000, 1–39 (2015) Preprint 29 January 2016 Compiled using MNRAS LATEXstylefilev3.0 The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of He ii λ1640 in young star clusters Paul A. Crowther1⋆, S.M. Caballero-Nieves1, K.A. Bostroem2,3,J.Ma´ız Apell´aniz4, F.R.N. Schneider5,6,N.R.Walborn2,C.R.Angus1,7,I.Brott8,A.Bonanos9, A. de Koter10,11,S.E.deMink10,C.J.Evans12,G.Gr¨afener13,A.Herrero14,15, I.D. Howarth16, N. Langer6,D.J.Lennon17,J.Puls18,H.Sana2,11,J.S.Vink13 1Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK 2Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD 21218, USA 3Department of Physics, University of California, Davis, 1 Shields Ave, Davis CA 95616, USA 4Centro de Astrobiologi´a, CSIC/INTA, Campus ESAC, Apartado Postal 78, E-28 691 Villanueva de la Ca˜nada, Madrid, Spain 5 Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH, UK 6 Argelanger-Institut fur¨ Astronomie der Universit¨at Bonn, Auf dem Hugel¨ 71, D-53121 Bonn, Germany 7 Department of Physics, University of Warwick, Gibbet Hill Rd, Coventry CV4 7AL, UK 8 Institute for Astrophysics, Tuerkenschanzstr. 17, AT-1180 Vienna, Austria 9 Institute of Astronomy & Astrophysics, National Observatory of Athens, I. Metaxa & Vas. Pavlou St, P. Penteli 15236, Greece 10 Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ, Amsterdam, Netherlands 11 Institute of Astronomy, KU Leuven, Celestijnenlaan -
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 -
Effects of Rotation Arund the Axis on the Stars, Galaxy and Rotation of Universe* Weitter Duckss1
Effects of Rotation Arund the Axis on the Stars, Galaxy and Rotation of Universe* Weitter Duckss1 1Independent Researcher, Zadar, Croatia *Project: https://www.svemir-ipaksevrti.com/Universe-and-rotation.html; (https://www.svemir-ipaksevrti.com/) Abstract: The article analyzes the blueshift of the objects, through realized measurements of galaxies, mergers and collisions of galaxies and clusters of galaxies and measurements of different galactic speeds, where the closer galaxies move faster than the significantly more distant ones. The clusters of galaxies are analyzed through their non-zero value rotations and gravitational connection of objects inside a cluster, supercluster or a group of galaxies. The constant growth of objects and systems is visible through the constant influx of space material to Earth and other objects inside our system, through percussive craters, scattered around the system, collisions and mergers of objects, galaxies and clusters of galaxies. Atom and its formation, joining into pairs, growth and disintegration are analyzed through atoms of the same values of structure, different aggregate states and contiguous atoms of different aggregate states. The disintegration of complex atoms is followed with the temperature increase above the boiling point of atoms and compounds. The effects of rotation around an axis are analyzed from the small objects through stars, galaxies, superclusters and to the rotation of Universe. The objects' speeds of rotation and their effects are analyzed through the formation and appearance of a system (the formation of orbits, the asteroid belt, gas disk, the appearance of galaxies), its influence on temperature, surface gravity, the force of a magnetic field, the size of a radius. -
Gaia DR2 Reveals a Very Massive Runaway Star Ejected from R136
Astronomy & Astrophysics manuscript no. vfts16_submitted_revised c ESO 2018 July 25, 2018 Gaia DR2 reveals a very massive runaway star ejected from R136 D.J. Lennon1, C.J. Evans2, R.P. van der Marel3; 4, J. Anderson3, I. Platais4, A. Herrero5; 6, S.E. de Mink7, H. Sana8, E. Sabbi3, L.R. Bedin9, P.A. Crowther10, N. Langer11, M. Ramos Lerate12, A. del Pino3, M. Renzo7, S. Simón-Díaz5; 6, and F.R.N. Schneider13 1 ESA, European Space Astronomy Centre, Apdo. de Correos 78, E-28691 Villanueva de la Cañada, Madrid, Spain e-mail: [email protected] 2 UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, United Kingdom 3 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 4 Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA 5 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain 6 Departamento de Astrofísica, Universidad de La Laguna, E-38205, La Laguna, Tenerife, Spain 7 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands 8 Institute of astrophysics, KU Leuven, Celestijnlaan 200D, 3001, Leuven, Belgium 9 INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy 10 Department of Physics and Astronomy, Hicks Building, Hounsfield Road, University of Sheffield, Sheffield S3 7RH, United Kingdom 11 Argelander-Institüt für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121, Bonn, Germany 12 VitrocisetBelgium for ESA, European Space Astronomy Centre, Apdo. de Correos 78, E-28691 Villanueva de la Cañada, Madrid, Spain 13 Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom Received ; accepted ABSTRACT A previous spectroscopic study identified the very massive O2 III star VFTS 16 in the Tarantula Nebula as a runaway star based on its peculiar line-of-sight velocity. -
The R136 Star Cluster Dissected with Hubble Space Telescope/STIS
MNRAS 458, 624–659 (2016) doi:10.1093/mnras/stw273 Advance Access publication 2016 February 5 The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of He II λ1640 in young star clusters Paul A. Crowther,1‹ S. M. Caballero-Nieves,1 K. A. Bostroem,2,3 J. Ma´ız Apellaniz,´ 4 F. R. N. Schneider,5,6 N. R. Walborn,2 C. R. Angus,1,7 I. Brott,8 A. Bonanos,9 A. de Koter,10,11 S. E. de Mink,10 C. J. Evans,12 G. Grafener,¨ 13 A. Herrero,14,15 I. D. Howarth,16 N. Langer,6 D. J. Lennon,17 J. Puls,18 H. Sana2,11 andJ.S.Vink13 Affiliations are listed at the end of the paper Accepted 2016 February 1. Received 2016 January 29; in original form 2015 October 23 ABSTRACT We introduce a Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph (STIS) stellar census of R136a, the central ionizing star cluster of 30 Doradus. We present low resolu- tion far-ultraviolet STIS spectroscopy of R136 using 17 contiguous 52 arcsec × 0.2 arcsec slits which together provide complete coverage of the central 0.85 parsec (3.4 arcsec). We provide spectral types of 90 per cent of the 57 sources brighter than mF555W = 16.0 mag within a radius of 0.5 parsec of R136a1, plus 8 additional nearby sources including R136b (O4 If/WN8). We measure wind velocities for 52 early-type stars from C IVλλ1548–51, including 16 O2–3 stars. -
The Age, Life Expectancy, and Space Density of Post Common Envelope
Astronomy & Astrophysics manuscript no. ms3351 31st October 2018 (DOI: will be inserted by hand later) The age, life expectancy, and space density of Post Common Envelope Binaries M.R. Schreiber1 and B.T. G¨ansicke2 1 Universit´eLouis Pasteur, Observatoire de Strasbourg, 11 rue de l’Universit´e, 67000 Strasbourg, France 2 Department of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ, UK Received ; accepted Abstract We present a sample of 30 well observed Post Common Envelope Binaries (PCEBs). Deriving the cooling age of the white dwarfs, we show that the PCEB population is dominated by young systems. Having calculated the orbital evolution of the systems under the assumption of two different prescriptions for the angular momentum loss, we find that most of the systems have not yet completed a significant fraction of their PCEB life time. We < therefore predict the existence of a large population of old PCEBs containing cold white dwarfs (Teff ∼15 000 K). Our calculations show that nearly half of the PCEBs in our sample will evolve into a semi-detached configuration and start mass transfer in less than the Hubble-time. These systems are thus representative for progenitors of the current CV population. Only one of them (V471 Tau) will evolve into a long-period (Porb ∼> 4h) CV, and a significant fraction of the systems will start mass transfer in the period gap. Having estimated the distances of −6 −3 the PCEBs in the sample, we derive a space density of ρPCEB ∼ 6 − 30 × 10 pc , depending on the assumed angular momentum loss prescription. -
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International Journal of Astronomy 2020, 9(1): 3-11 DOI: 10.5923/j.astronomy.20200901.02 The Processes that Determine the Formation and Chemical Composition of the Atmosphere of the Body in Orbit Weitter Duckss Independent Researcher, Zadar, Croatia Abstract The goal of this article is to analyze the formation of an atmosphere on the orbiting planets and to determine the processes that participate in the formation of an atmospheric chemical composition, as well as in determining it. The research primarily analyzes the formation of atmospheres on the objects of different sizes (masses) and at the same or different orbital distances. This paper analyzes the influence of a star's temperature, the space and the orbit's distance to an object's temperature level, as well as the influence of the operating temperature of atoms and chemical compounds to chemical composition and the representation of elements and compounds in an atmosphere. The objects, which possess different masses and temperatures, are able to create and do create different compositions and sizes of atmospheres in the same or different distances from their main objects (Saturn/Titan or Pluto). The processes that are included in the formation of an atmosphere are the following: operating temperatures of compounds and atoms, migrations of hydrogen, helium and the other elements and compounds towards a superior mass. The lack of oxygen and hydrogen is additionally related to the level of temperature of space, which can be classified into internal (characterized by the lack of hydrogen) and the others (characterized by the lack of oxygen). Keywords Atmosphere, Chemical composition of the atmosphere, Migration of the atmosphere the atmosphere even though they are not in a gaseous state at 1. -
The VLT-FLAMES Tarantula Survey. XIV
UvA-DARE (Digital Academic Repository) The VLT-FLAMES Tarantula Survey. XIV. The O-type stellar content of 30 Doradus Walborn, N.R.; Sana, H.; Simón-Díaz, S.; Maíz Apellániz, J.; Taylor, W.D.; Evans, C.J.; Markova, N.; Lennon, D.J.; de Koter, A. DOI 10.1051/0004-6361/201323082 Publication date 2014 Document Version Final published version Published in Astronomy & Astrophysics Link to publication Citation for published version (APA): Walborn, N. R., Sana, H., Simón-Díaz, S., Maíz Apellániz, J., Taylor, W. D., Evans, C. J., Markova, N., Lennon, D. J., & de Koter, A. (2014). The VLT-FLAMES Tarantula Survey. XIV. The O-type stellar content of 30 Doradus. Astronomy & Astrophysics, 564, A40. https://doi.org/10.1051/0004-6361/201323082 General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:27 Sep 2021 A&A 564, A40 (2014) Astronomy DOI: 10.1051/0004-6361/201323082 & c ESO 2014 Astrophysics The VLT-FLAMES Tarantula Survey XIV. -
The VLT-FLAMES Tarantula Survey
A&A 570, A38 (2014) Astronomy DOI: 10.1051/0004-6361/201423643 & c ESO 2014 Astrophysics The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence? J. M. Bestenlehner1, G. Gräfener1, J. S. Vink1, F. Najarro2, A. de Koter3;4, H. Sana5, C. J. Evans6, P. A. Crowther7, V. Hénault-Brunet8, A. Herrero9;10, N. Langer11, F. R. N. Schneider11, S. Simón-Díaz9;10, W. D. Taylor6, and N. R. Walborn12 1 Armagh Observatory, College Hill, Armagh BT61 9DG, UK e-mail: [email protected] 2 Centro de Astrobiología (CSIC-INTA), Ctra. de Torrejón a Ajalvir km-4, 28850 Torrejón de Ardoz, Madrid, Spain 3 Astronomical Institute Anton Pannekoek, Amsterdam University, Science Park 904, 1098 XH, Amsterdam, The Netherlands 4 Instituut voor Sterrenkunde, Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium 5 ESA/STScI, 3700 San Martin Drive, Baltimore, MD21210, USA 6 UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK 7 Dept. of Physics & Astronomy, Hounsfield Road, University of Sheffield, S3 7RH, UK 8 Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, UK 9 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain 10 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain 11 Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany 12 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD 21218, USA Received 14 February 2014 / Accepted 4 July 2014 ABSTRACT The evolution and fate of very massive stars (VMS) is tightly connected to their mass-loss properties.