Exploració per tema "Estels nans"

Ara es mostren els items 1-20 de 103

    • 3D Hydrodynamical simulations of helium-ignited double-degenerate white dwarf mergers 

      Roy, Niranjan C.; Tiwari, Vishal; Bobrick, Alexey; Kosakowski, Daniel; Fisher, Robert; Perets, Hagai B.; Kashyap, Rahul; Lorén Aguilar, Pablo; García-Berro Montilla, Enrique (2022-06-01)
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      The origins of Type Ia supernovae (SNe Ia) are still debated. Some of the leading scenarios involve a double detonation in double white dwarf (WD) systems. In these scenarios, helium shell detonation occurs on top of a ...

    • A common origin of magnetism from planets to white dwarfs 

      Isern Vilaboy, Jordi; García-Berro Montilla, Enrique; Kulebi, Baybar; Lorén Aguilar, Pablo (2017-02-20)
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      Isolated magnetic white dwarfs have field strengths ranging from kilogauss to gigagauss. However, the origin of the magnetic field has not been hitherto elucidated. Whether these fields are fossil, hence the remnants of ...

    • A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation 

      Camisassa, María Eugenia; Torres Gil, Santiago; Hollands, Mark; Koester, Detlev; Raddi, Roberto; Althaus, Leandro G.; Rebassa Mansergas, Alberto (EDP Sciences, 2023-06-01)
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      Context. The high-quality photometric and astrometric capabilities of the ESA Gaia space mission have revealed a bifurcation of the white dwarf sequence on the color magnitude diagram with two branches: A and B. While the ...

    • A population synthesis fitting of the Gaia resolved white dwarf binary population within 100 pc 

      Torres Gil, Santiago; Canals Canals, Pere; Jiménez Esteban, F. M.; Rebassa Mansergas, Alberto; Solano Márquez, Enrique (Oxford University Press, 2022-04-01)
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      The Gaia mission has provided an unprecedented wealth of information about the white dwarf population of our Galaxy. In particular, our studies show that the sample up to 100\,pc from the Sun can be considered as practically ...

    • A population synthesis study of the luminosity function of hot white dwarfs 

      Torres Gil, Santiago; García-Berro Montilla, Enrique; Krzesinski, Jurek; Kleinman, Scot J. (2014-03-05)
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      Context. We present a coherent and detailed Monte Carlo simulation of the population of hot white dwarfs. We assess the statistical significance of the hot end of the white dwarf luminosity function and the role played by ...

    • A population synthesis study of the MS+WD population in the SDSS 

      García-Berro Montilla, Enrique; Torres Gil, Santiago; Camacho Díaz, Judit; Rebassa Mansergas, Alberto; Gänsicke, Boris T.; Schreiber, Mathias R.; Zorotovic, Mónica (Astronomical Society of the Pacific Conference Series (ASP), 2015-06-01)
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      Detached white dwarf + main sequence (WD+MS) systems represent the simplest population of post-common envelope binaries (PCEBs), and their ensemble properties carry important information about common-envelope phase. However, ...

    • A population synthesis study of the MS+WD population in the SDSS 

      García-Berro Montilla, Enrique; Torres Gil, Santiago; Camacho Díaz, Judit; Rebassa Mansergas, Alberto; Gänsicke, Boris T.; Schreiber, Mathias R.; Zorotovic, Mónica (2014)
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      Accés restringit per política de l'editorial

    • A population synthesis study of white dwarf-main sequence binaries in the galactic disk 

      Rebassa Mansergas, Alberto; García-Berro Montilla, Enrique; Torres Gil, Santiago (2017)
      Text en actes de congrés
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      The companion mass ratio distribution (CMRD) of main sequence binaries is a crucial physical quantity for understanding the evolution of stars in binary systems and for constraining models of binary star formation. However, ...

    • A white dwarf catalogue from Gaia-DR2 and the Virtual Observatory 

      Jiménez Esteban, F. M.; Torres Gil, Santiago; Rebassa Mansergas, Alberto; Skorobogatov, G.; Cantero, C. (Oxford University Press, 2018-01-01)
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      We present a catalogue of 73¿221 white dwarf candidates extracted from the astrometric and photometric data of the recently published Gaia-DR2 catalogue. White dwarfs were selected from the Gaia Hertzsprung–Russell diagram ...

    • A white dwarf merger as progenitor of the anomalous X-Ray pulsar 4U 0142+61? 

      Rueda, Jorge A.; Boshkayev, K.; Izzo, L.; Ruffini, R.; Lorén Aguilar, Pablo; Kuelebi, B.; Aznar Siguan, Gabriela; García-Berro Montilla, Enrique (2013-08)
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      It has been recently proposed that massive, fast-rotating, highly magnetized white dwarfs could describe the observational properties of some of soft gamma-ray repeaters and anomalous X-ray pulsars (AXPs). Moreover, it has ...

    • Accurate mass and radius determinations of a cool subdwarf in an eclipsing binary 

      Rebassa Mansergas, Alberto; Parsons, Steven G.; Dhillon, Vikram S.; Ren, Juanjuan; Littlefair, Stuart P.; Marsh, Thomas R.; Torres Gil, Santiago (Springer Nature, 2019-04-08)
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      Cool subdwarfs are metal-poor low-mass stars that formed during the early stages of the evolution of our Galaxy. Because they are relatively rare in the vicinity of the Sun, we know of few cool subdwarfs in the solar ...

    • An asteroseismic constraint on the mass of the axion from the period drift of the pulsating da white dwarf star L19-2 

      Córsico, Alejandro H.; Romero, Alejandra Daniela; Althaus, Leandro G.; García-Berro Montilla, Enrique; Isern Vilaboy, Jordi; Kepler, S.O.; Miller Bartolami, Marcelo M.; Sullivan, Denis J. (2016-07-01)
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      We employ an asteroseismic model of L19-2, a relatively massive (Msstarf ~ 0.75 M¿) and hot (Teff ~ 12 100 K) pulsating DA (H-rich atmosphere) white dwarf star (DAV or ZZ Ceti variable), and use the observed values of the ...

    • An extremely hot white dwarf with a rapidly rotating K-type subgiant companion: UCAC2 46706450 

      Werner, Klaus; Reindl, Nicole; Löbling, Lisa; Pelisoli, Ingrid; Schaffenroth, Veronika; Rebassa Mansergas, Alberto; Irawati, Puji; Ren, Juanjuan (EDP Sciences, 2020-10-01)
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      Realitzat a/amb:   Eberhard Karls Universität Tübingen / Universität Potsdam / Institut d'Estudis Espacials de Catalunya / National Astronomical Research Institute of Thailand / Zhongguo ke xue yuan
      The subgiant UCAC2 46706450 is a late-type star with an ultraviolet (UV) excess. It was considered as a candidate to establish a sample of stars of spectral type F, G, and K with white dwarf (WD) companions that could be ...

    • An irradiated-Jupiter analogue hotter than the Sun 

      Hallakoun, Na'ama; Maoz, Dan; Istrate, Alina G.; Badenes, Carles; Breedt, Elmé; Gänsicke, Boris T.; Jha, Saurabh; Leibundgut, Bruno; Mannucci, Filippo; Marsh, Thomas R.; Nelemans, Gijs; Patat, Ferdinando; Rebassa Mansergas, Alberto (Springer Nature, 2023-09-14)
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      Planets orbiting close to hot stars experience intense extreme-ultraviolet radiation, potentially leading to atmosphere evaporation and to thermal dissociation of molecules. However, this extreme regime remains mainly ...

    • Can we reveal the core-chemical composition of ultra-massive white dwarfs through their magnetic fields? 

      Camisassa, María Eugenia; Raddi, Roberto; Althaus, Leandro G.; Isern Vilaboy, Jordi; Rebassa Mansergas, Alberto; Torres, Santiago; Córsico, Alejandro H.; Korre, Lydia (Oxford University Press, 2022-10-01)
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      Ultra-massive white dwarfs (1.05M¿ . MWD) are particularly interesting objects that allow us to study extreme astrophysical phenomena such as type Ia supernovae explosions and merger events. Traditionally, ultra-massive ...

    • Carbon-oxygen ultra-massive white dwarfs in general relativity 

      Althaus, Leandro G.; Corsico, Alejandro H.; Camisassa, María Eugenia; Torres Gil, Santiago; Gil Pons, Pilar; Rebassa Mansergas, Alberto; Raddi, Roberto (Oxford University Press, 2023-08-01)
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      We employ the La Plata stellar evolution code, lpcode, to compute the first set of constant rest-mass carbon–oxygen ultra-massive white dwarf evolutionary sequences for masses higher than 1.29 M¿ that fully take into account ...

    • Comparison of theoretical white dwarf cooling timescales (Research Note) 

      Salaris, Maurizio; Althaus, Leandro Gabriel; García-Berro Montilla, Enrique (2013-07)
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      Context. An accurate assessment of white dwarf cooling times is paramount so that white dwarf cosmochronology of Galactic populations can be put on more solid grounds. This issue is particularly relevant in view of the ...

    • Constraining the double-degenerate scenario for Type Ia supernovae from merger ejected matter 

      Levanon, Naveh; Soker, Noam; García-Berro Montilla, Enrique (2015-03-01)
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      We follow the mass expelled during the WD-WD merger process in a particular case of the double-degenerate (DD) scenario for Type Ia supernovae (SNe Ia), and find that the interaction of the SN ejecta with the resulting ...

    • Constraining the neutrino magnetic dipole moment from white dwarf pulsations 

      Corsico, Alejandro H.; Althaus, Leandro G.; Miller Bartolami, Marcelo M.; Kepler, S.O.; García-Berro Montilla, Enrique (2014-08-01)
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      Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models ...

    • Detached cataclysmic variables are crossing the orbital period gap 

      Zorotovic, Mónica; Schreiber, Mathias R.; Parsons, S. G.; Gaensicke, B. T.; Hardy, A.; Agurto Gangas, C.; Nebot Gómez-Moran, Ada; Rebassa Mansergas, Alberto; Schowpe, A. D. (2016-04-21)
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      A central hypothesis in the theory of cataclysmic variable (CV) evolution is the need to explain the observed lack of accreting systems in the similar or equal to 2-3 h orbital period range, known as the period gap. The ...