DOCSLIB.ORG

Ecology of Blue Straggler Stars ESO@50 – the First 50 Years Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ecology of Blue Straggler Stars ESO@50 – the First 50 Years Of Astronomical News Announcement of the Conference ESO@50 – The First 50 Years of ESO 3–7 September 2012, ESO Headquarters, Garching, Germany A special science workshop will be held results, and an outlook for science with Isobel Hook (United Kingdom); Konrad at ESO Headquarters to mark the 50th the E-ELT. Kuijken (the Netherlands); Bruno anniversary. The ESO@50 workshop is Leibundgut (ESO); Maria-Teresa Ruiz intended to provide an original perspec- The meeting will consist of invited reviews (Chile); Monica Tosi (Italy); Linda Tacconi tive on the scientific challenges of the and contributed talks covering the many (Germany); Michael West (ESO). coming decade, building on the achieve- diverse scientific areas in which ESO has ments from the science community contributed, including the Solar System, The Local Organising Committee is using ESO facilities. This five­day work- exoplanets, stellar birth and the interstel- composed of Eric Emsellem, Bruno shop will focus on the main scientific lar medium, stellar death, the Milky Way, Leibundgut, Jorge Melnick, Markus topics where ESO has made important nearby galaxies, galaxy surveys, distant Kissler-Patig, Christina Stoffer, Leonardo contributions. Key speakers will be invited galaxies, galaxy clusters and cosmology. Testi, Svea Teupke and Michael West. to give overviews of each field (includ­ ing some historical perspective) and then The distinguished Scientific Organising The registration deadline is 31 May 2012. focusing on the present science status Committee is composed of: Beatriz surrounding these questions. The next Barbuy (Brazil); Xavier Barcons (Spain; Further details are available at: science steps will also be emphasised. president of ESO Council); Willy Benz http://www.eso.org/sci/meetings/2012/ Some “bonus” tracks will be included, (Switzerland); Jacqueline Bergeron ESOat50.html or by email to: such as introducing the first ALMA results, (France); Emanuele Daddi (France); Tim [email protected] the latest unpublished VLT/I and La Silla de Zeeuw (ESO); Eric Emsellem (ESO); Announcement of the ESO Workshop Ecology of Blue Straggler Stars 5–9 November 2012, ESO Vitacura, Santiago, Chile An accumulation of observational evi- as of the dynamics of clusters. Spread dence now points to the fact that the two over a week and held at the ESO-Chile mechanisms thought to be responsible headquarters in Santiago, the workshop for blue stragglers – mergers and mass will consist of extended invited reviews, transfer – are operating in the same with ample time for contributed talks and cluster: the exact preponderance of one space for posters. mechanism over the other possibly depending on the cluster’s property, that The scientific organising committee is is, the blue stragglers’ ecology. For exam- composed of: Giovanni Carraro (ESO, ple, it would seem natural that the most co­chair); Henri Boffin (ESO, co­chair); populous systems, i.e. globular clusters, Giacomo Beccari (ESO); Alison Sills should produce the largest population (McMaster University, Canada); Melvyn of blue stragglers, irrespective of the Davies (Lund University, Sweden); The existence of blue straggler stars, mechanism involved. Recently, however, Francesco Ferraro (University of Bologna, which appear younger, hotter, and more it was shown that Galactic open clusters Italy); Robert Mathieu (University of massive than their siblings, is at odds seem to contain the largest proportions Wisconsin, USA); Hagai Perets (Harvard with a simple picture of stellar evolution, of blue stragglers, a proportion only University, USA); and Javier Ahumada as such stars should have exhausted approached by the low luminosity dSphs. (Universidad de Córdoba, Argentina). their nuclear fuel and evolved long ago to become cooling white dwarfs. Obser- This is the first workshop ever devoted The registration deadline is 31 July 2012. vations have revealed that blue stragglers to these unique objects. The workshop exist in globular clusters, open clusters, aims at bringing together theoreticians Further details are available at: dwarf spheroidal galaxies (dSph) of the and observers in order to compose a http://www.eso.org/sci/meetings/2012/ Local Group and OB associations. Field complete picture of the progress in the bss2012.html, or by e-mail to: blue stragglers have also been identi- field. It will also bring together specialists [email protected] fied from their anomalous kinematics and of binaries and multiple systems, stellar metallicity. evolution and stellar populations, as well The Messenger 147 – March 2012 47.
Load more

Recommended publications
  • Blue Stragglers in Open Clusters?
    A&A 366, 490–497 (2001) Astronomy DOI: 10.1051/0004-6361:20000213 & c ESO 2001 Astrophysics Blue stragglers in open clusters? III. NGC 7789 D. Sch¨onberner1, S. M. Andrievsky1,2,3, and J. S. Drilling4 1 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: [email protected] 2 Department of Astronomy, Odessa State University, Shevchenko Park, 65014, Odessa, Ukraine 3 Isaac Newton Institute of Chile, Odessa Branch, Chile e-mail: [email protected] 4 Louisiana State University, Department of Physics and Astronomy, Baton Rouge, Louisiana 70803, USA e-mail: [email protected] Received 8 September 2000 / Accepted 7 November 2000 Abstract. We performed for the first time a detailed LTE spectroscopic study of a sample of blue straggler stars in the moderately old open cluster NGC 7789. For eight stars the parameters and abundances of several elements were determined. The cluster members show a remarkable surface magnesium deficiency which is quite unusual for late B - early A stars. Iron and titanium abundances are in agreement with other photometric and spectroscopic estimates of the NGC 7789 metallicity. All the confirmed blue stragglers have rather low projected rotational velocities (with one exception for K88, v sin i =80kms−1). Key words. stars: open clusters and associations: individual: NGC 7789 – stars: blue stragglers – stars: abundances 1. Introduction internal mixing processes, but that they rather evolve like normal stars. The moderately old open cluster NGC 7789 is among those In recent years interest in the NGC 7789 blue strag- having very rich blue-straggler populations.
    [Show full text]
  • BD+43° 3654 – a Blue Straggler?
    A&A 485, L29–L32 (2008) Astronomy DOI: 10.1051/0004-6361:200809860 & c ESO 2008 Astrophysics Letter to the Editor BD+43◦ 3654 – a blue straggler? V. V. Gvaramadze1,2 and D. J. Bomans1 1 Astronomical Institute, Ruhr-University Bochum, Universitätstr. 150, 44780 Bochum, Germany e-mail: [email protected] 2 Sternberg Astronomical Institute, Moscow State University, Universitetskij Pr. 13, Moscow 119992, Russia e-mail: [email protected] Received 27 March 2008 / Accepted 22 May 2008 ABSTRACT The astrometric data on the runaway star BD+43◦ 3654 are consistent with the origin of this O4If star in the center of the Cyg OB2 association, while BD+43◦ 3654 is younger than the association. To reconcile this discrepancy, we suggest that BD+43◦ 3654 is a blue straggler formed via a close encounter between two tight massive binaries in the core of Cyg OB2. A possible implication of this suggestion is that the very massive (and therefore apparently very young) stars in Cyg OB2 could be blue stragglers as well. We also suggest that the binary-binary encounter producing BD+43◦ 3654 might be responsible for ejection of two high-velocity stars (the stripped helium cores of massive stars) – the progenitors of the pulsars B2020+28 and B2021+51. Key words. stars: kinematics – pulsars: individual: PSR B2020+28 – open clusters and associations: individual: Cyg OB2 – stars: individual: BD+43◦ 3654 1. Introduction Interestingly, Cyg OB2 may be associated with the origin of + + ◦ ◦ two high-velocity pulsars, PSR B2020 28 and PSR B2021 51. BD+43 3654 is a massive (O4If) runaway star located ∼2.7 The high-precision proper motion and parallax measurements northeast of the Cyg OB2 association (Comerón & Pasquali ∼ ◦ ◦ for these pulsars (presently separated by 23 ) lead to the sug- 2007).
    [Show full text]
  • ESO Annual Report 2004 ESO Annual Report 2004 Presented to the Council by the Director General Dr
    ESO Annual Report 2004 ESO Annual Report 2004 presented to the Council by the Director General Dr. Catherine Cesarsky View of La Silla from the 3.6-m telescope. ESO is the foremost intergovernmental European Science and Technology organi- sation in the field of ground-based as- trophysics. It is supported by eleven coun- tries: Belgium, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Sweden, Switzerland and the United Kingdom. Created in 1962, ESO provides state-of- the-art research facilities to European astronomers and astrophysicists. In pur- suit of this task, ESO’s activities cover a wide spectrum including the design and construction of world-class ground-based observational facilities for the member- state scientists, large telescope projects, design of innovative scientific instruments, developing new and advanced techno- logies, furthering European co-operation and carrying out European educational programmes. ESO operates at three sites in the Ataca- ma desert region of Chile. The first site The VLT is a most unusual telescope, is at La Silla, a mountain 600 km north of based on the latest technology. It is not Santiago de Chile, at 2 400 m altitude. just one, but an array of 4 telescopes, It is equipped with several optical tele- each with a main mirror of 8.2-m diame- scopes with mirror diameters of up to ter. With one such telescope, images 3.6-metres. The 3.5-m New Technology of celestial objects as faint as magnitude Telescope (NTT) was the first in the 30 have been obtained in a one-hour ex- world to have a computer-controlled main posure.
    [Show full text]
  • HIP 10725: the First Solar Twin/Analogue Field Blue Straggler
    A&A 584, A116 (2015) Astronomy DOI: 10.1051/0004-6361/201527303 & c ESO 2015 Astrophysics HIP 10725: The first solar twin/analogue field blue straggler, Lucas Schirbel1, Jorge Meléndez1, Amanda I. Karakas2, Iván Ramírez3, Matthieu Castro4, Marcos A. Faria5, Maria Lugaro6, Martin Asplund2, Marcelo Tucci Maia1, David Yong2, Louise Howes2, and José D. do Nascimento Jr.4,7 1 Universidade de São Paulo, Departamento de Astronomia do IAG/USP, Rua do Matão 1226, Cidade Universitária, 05508-900 São Paulo, SP, Brazil e-mail: [email protected] 2 The Australian National University, Research School of Astronomy and Astrophysics, Cotter Road, Weston, ACT 2611, Australia 3 University of Texas at Austin, McDonald Observatory and Department of Astronomy, TX 78712 Austin, USA 4 Universidade Federal do Rio Grande do Norte, Departamento de Física Teórica e Experimental, 59072-970 Natal, RN, Brazil 5 Universidade Federal de Itajubá, DFQ – Instituto de Ciências Exatas, 37 500-903 Itajubá, MG, Brazil 6 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15–17, 1121 Budapest, Hungary 7 Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA Received 3 September 2015 / Accepted 2 October 2015 ABSTRACT Context. Blue stragglers are easy to identify in globular clusters, but are much harder to identify in the field. Here we present the serendipitous discovery of one field blue straggler, HIP 10725, that closely matches the Sun in mass and age, but with a metallicity slightly lower than solar. Aims. We characterise the solar twin/analogue HIP 10725 to assess whether this star is a blue straggler.
    [Show full text]
  • Young Blue Straggler Stars in the Galactic Field Gemunu Ekanayake Manhattanville College
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Kentucky University of Kentucky UKnowledge Physics and Astronomy Faculty Publications Physics and Astronomy 6-19-2018 Young Blue Straggler Stars in the Galactic Field Gemunu Ekanayake Manhattanville College Ronald Wilhelm University of Kentucky, [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits oy u. Follow this and additional works at: https://uknowledge.uky.edu/physastron_facpub Part of the Astrophysics and Astronomy Commons, and the Physics Commons Repository Citation Ekanayake, Gemunu and Wilhelm, Ronald, "Young Blue Straggler Stars in the Galactic Field" (2018). Physics and Astronomy Faculty Publications. 641. https://uknowledge.uky.edu/physastron_facpub/641 This Article is brought to you for free and open access by the Physics and Astronomy at UKnowledge. It has been accepted for inclusion in Physics and Astronomy Faculty Publications by an authorized administrator of UKnowledge. For more information, please contact [email protected]. Young Blue Straggler Stars in the Galactic Field Notes/Citation Information Published in Monthly Notices of the Royal Astronomical Society, v. 479, issue 2, p. 2623-2629. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. The opc yright holders have granted the
    [Show full text]
  • Hunting for Optical Companions to Binary Msps in Terzan 5
    MAD Science Demonstration Proposal Hunting for optical companions to binary MSPs in Terzan 5 Investigators Institute EMAIL Francesco R. Ferraro Univ. Bologna (Italy) [email protected] Elena Valenti ESO - Chile [email protected] Barbara Lanzoni Univ. Bologna (Italy) [email protected] Giacomo Beccari Univ. Bologna (Italy) [email protected] Gabriele Cocozza Univ. Bologna (Italy) [email protected] Emanuele Dalessandro Univ. Bologna (Italy) [email protected] Scott Ransom NRAO - (USA) [email protected] Robert T. Rood Univ of Virginia - (USA) [email protected] Abstract: We propose deep MAD observations to search for optical companions to the known binary Millisecond Pulsars (MSPs) in the highly reddened Globular Cluster (GC) Terzan 5. The optical identification of MSP companions is crucial for unveiling the formation, evolution and recycling process of pulsars. In addition, since most of MSPs are formed via stellar interactions, determining the nature and photometric properties of their companions places significant constraints on the dynamical processes acting in GCs and their impact on the (otherwise normal) stellar evolution. Remarkably, the study of binary MSPs has also an intrisic importance for fundamental physics, since it offers the opportunity to constrain the equation of state of matter at nuclear density. Only 6 optical counterparts to binary MSP companions are known to date in the entire Galactic GC system, and 3 of them have been discovered by our group. The proposed MAD observations could easily double/triple the existing sample. Indeed, among the GCs in which MSP have been detected, Terzan 5 is by far the most surprising: it hosts the largest MSP population (33 objects) of any GC, thus comprising roughly 25% of the known GC MSPs! Even more interesting, 17 of them are in binary systems and 15 are located within a 10 × 10 region, corresponding to the MAD field of view.
    [Show full text]
  • Optical Studies of X-Ray Sources in the Old Open Cluster M 67
    Optical studies of X-ray sources in the old open cluster M 67 Figures 1.1 and 8.1, the images in the chapter headings and the images at the end are created from the Digitized Sky Survey c 2001 Maureen van den Berg Alle rechten voorbehouden. Niets in deze uitgave mag worden verveelvoudigd, opgesla- gen in een geautomatiseerd gegevensbestand, of openbaar gemaakt, in enige vorm, zonder schriftelijke toestemming van de auteur ISBN 90-393-2679-7 Optical studies of X-ray sources in the old open cluster M 67 Optische studies van rontgenbronnen¨ in de oude open sterrenhoop M 67 (met een samenvatting in het Nederlands) Proefschrift ter verkrijging van de graad van doctor aan de Universiteit Utrecht op gezag van de Rector Magnificus prof. dr H.O. Voorma ingevolge het besluit van het College voor Promoties, in het openbaar te verdedigen op woensdag 21 maart 2001 des ochtends te 10.30 uur door Maureen Constance van den Berg geboren op 6 april 1972 te Maastricht PROMOTOR prof. dr Frank Verbunt Dit proefschrift werd mede mogelijk gemaakt met financiele¨ steun van de Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO). Contents 1 Introduction 1 1.1 Blue stragglers, yellow stragglers and sub-subgiants 1 1.2 X-ray observations of old open clusters 3 1.3 Summary: peculiar X-ray sources in M 67, NGC 752 and NGC 6940 5 2 Optical spectroscopy of X-ray sources in the old open cluster M67 9 2.1 Introduction 10 2.2 Observations and data reduction 12 2.2.1 Low-resolution spectra 14 2.2.2 High-resolution spectra 14 2.3 Data analysis 15 2.3.1 Determination of Ca II H&K emission fluxes 15 2.3.2 Determination of projected rotational velocities 17 2.4 Results 19 2.4.1 Comparison with RS CVn binaries 19 2.4.2 Activity indicators 21 2.4.3 Individual systems 22 2.5 Discussion and conclusions 26 3 Photometric variability in the old open cluster M 67 I.
    [Show full text]
  • Blue Supergiants As Descendants of Magnetic Main Sequence Stars
    A&A 584, A54 (2015) Astronomy DOI: 10.1051/0004-6361/201526302 & c ESO 2015 Astrophysics Blue supergiants as descendants of magnetic main sequence stars I. Petermann, N. Langer, N. Castro, and L. Fossati Argelander Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany e-mail: [email protected] Received 13 April 2015 / Accepted 5 July 2015 ABSTRACT About 10% of the massive main sequence stars have recently been found to host a strong, large scale magnetic field. Both, the origin and the evolutionary consequences of these fields are largely unknown. We argue that these fields may be sufficiently strong in the deep interior of the stars to suppress convection near the outer edge of their convective core. We performed parametrised stellar evolution calculations and assumed a reduced size of the convective core for stars in the mass range 16 M to 28 M from the zero age main sequence until core carbon depletion. We find that such models avoid the coolest part of the main sequence band, which is usually filled by evolutionary models that include convective core overshooting. Furthermore, our “magnetic” models populate the blue supergiant region during core helium burning, i.e., the post-main sequence gap left by ordinary single star models, and some of them end their life in a position near that of the progenitor of Supernova 1987A in the Hertzsprung-Russell diagram. Further effects include a strongly reduced luminosity during the red supergiant stage, and downward shift of the limiting initial mass for white dwarf and neutron star formation.
    [Show full text]
  • AST201 Assignment 2 Solution 1 a Puzzling Binary
    AST201 Assignment 2 Solution 1 A puzzling binary PSR B2303+46 is a radio pulsar in an eccentric binary with a 12-day orbit. Prof. Shri Kulkarni (of the California Institute of Technology) and one of your instructors (MHvK) have found that the other star in the binary is a massive white dwarf. Given that the binary is eccentric, we know that the last thing that happened was the supernova explosion that formed the pulsar. Thus, the pulsar in this binary was formed later than the white dwarf. (a) [5 points] Look up for what initial masses a star is expected to end its life by forming a neutron star, and for what initial masses it is expected to leave a white dwarf. Which is expected to live longer, the ones that leave neutron stars or those that leave white dwarfs? Given this, and the fact that stars in binaries are born at the same time, what is puzzling about the above binary?Feel free to answer this question in point form. Solution. From the book (e.g., p. 574), stars with masses above 8 M end as neutron stars [1 point], stars with masses below as white dwarfs [1 point]. Stars forming a neutron star live shorter [1 point], since they are more massive [1 point]. Thus, in the binary one would have expected the neutron star to form first rather than second [1 point]. Many people said 4-8M was the range for neutron star from the NASA website. This is a case where a seemingly respective source is not correct.
    [Show full text]
  • An Optical Study of X-Ray Sources in the Old Open Clusters NGC 752 and NGC 6940?
    A&A 375, 387–396 (2001) Astronomy DOI: 10.1051/0004-6361:20010767 & c ESO 2001 Astrophysics An optical study of X-ray sources in the old open clusters NGC 752 and NGC 6940? M. van den Berg and F. Verbunt Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands Received 20 April 2001 / Accepted 22 May 2001 Abstract. We observed the optical counterparts of X-ray sources in the old open clusters NGC 752 and NGC 6940 to search for the origin of the X-rays. The photometric variability reported earlier for the blue straggler H 209 is not confirmed by our light curves, nor is an indication for variability seen in the spectra; thus its X-rays remain unexplained. The X-rays of VR 111 and VR 114 are likely not a result of magnetic activity as these stars lack strong Ca II H&K emission, while in VR 108 the level of activity could be enhanced. The short-period binary H 313 is a photometric variable; this supports the interpretation that it is a magnetically active binary. From the detection of the Li I 6707.8 A˚ line, we classify the giant in VR 84 as a first-ascent giant; this leaves its circular orbit unexplained. As a side-result we report the detection of Li I 6707.8 A˚ in the spectrum of the giant H 3 and the absence of this line in the spectrum of the giant H 11; this classifies H 3 as a first-ascent giant and H 11 as a core-helium-burning clump star, and confirms the faint extension of the red-giant clump in NGC 752.
    [Show full text]
  • Summary in English
    Cover Page The handle http://hdl.handle.net/1887/38640 holds various files of this Leiden University dissertation Author: Rimoldi, Alexander Title: Clues from stellar catastrophes Issue Date: 2016-03-29 esis summary 131 Thesis summary Stellar catastrophes A star much more massive than our Sun ends its life in a spectacular fashion. Once its nuclear fuel is exhausted, the core of such a star can no longer support itself, and collapses into a compact object—either a neutron star or a black hole. Within sec- onds, the remaining outer layers of the star are violently expelled in a (core-collapse) supernova explosion. An immense amount of energy is released in a supernova—about 100 times more than what the Sun will provide over its entire 10 billion year lifetime. Nearly all of this energy is quietly carried away by neutrinos, particles that are copiously produced during the supernova but are almost undetectable through their weak interaction with other matter. Only 0.01% of the energy is emitted as the light that so conspicuously signals the death of the star. Despite being such a small fraction of the total energy, in its earliest days the luminosity of a supernova is still enough to outshine a whole galaxy worth of stars. e remaining energy, about 1% of the total, goes into the motion of the gas that is shed from the star during the explosion. As this material, the supernova ejecta, expands into the surrounding medium, it sweeps up more gas, and evolves as a supernova remnant (Figure 5.8). Supernova remnants feature in most chapters of this thesis.
    [Show full text]
  • Detection of White Dwarf Companions to Blue Straggler Stars from UVIT Observations of M67
    Star Clusters: From the Milky Way to the Early Universe Proceedings IAU Symposium No. 351, 2019 c International Astronomical Union 2020 A. Bragaglia, M. Davies, A. Sills & E. Vesperini, eds. doi:10.1017/S1743921319006975 Detection of White Dwarf companions to Blue Straggler Stars from UVIT observations of M67 Sindhu N1,2 , Annapurni Subramaniam2, Aaron M. Geller3,4,Vikrant Jadhav2,5, Christian Knigge6, Mirko Simunovic7,8,NathanLeigh9,10, Michael Shara10 and Thomas H. Puzia11 1School of Advanced Sciences, VIT, Vellore -632014, India email: [email protected] 2Indian Institute of Astrophysics, Koramangala II Block, Bangalore-560034, India 3CIERA and Department of Physics & Astronomy, Northwestern University, Evanston, IL 60201, USA 4Adler Planetarium, Dept. of Astronomy, Chicago, IL 60605, USA 5JAP and Physics Department, Indian Institute of Science, Bangalore - 560012, India 6School of Physics and Astronomy, University of Southampton, Southampton, UK 7Gemini Observatory, 670 N Aohoku Pl, Hilo, Hawaii 96720 8Subaru Telescope, 650 N Aohoku Pl, Hilo, Hawaii 96720, USA 9Departamento de Astronom´ıa, Facultad de Ciencias F´ısicas y Matem´aticas, Universidad de Concepci´on, Concepci´on, Chile 10Department of Astrophysics, American Museum of Natural History, NY 10024, USA 11Institute of Astrophysics, Pontificia Universidad Cat´olica de Chile, Santiago, Chile Abstract. We investigate the old open cluster M67 using ultraviolet photometric data of Ultra- Violet Imaging Telescope in multi-filter far-UV bands. M67, well known for the presence of several blue straggler stars (BSS), has been put to detailed tests to understand their formation pathways. Currently, there are three accepted formation channels: mass transfer due to Roche- lobe overflow in binary systems, stellar mergers either due to dynamical collisions or through coalescence of close binaries.
    [Show full text]