2013MNRAS.430.2302T
Abell 48 - a rare WN-type central star of a planetary nebula
Todt, H. ( University of Potsdam, Institute of Physics and Astronomy, D-14476 Potsdam, Germany; ); Kniazev, A. Y. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa; Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow, Russia ); Gvaramadze, V. V. ( Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow, Russia; Isaac Newton Institute of Chile, Moscow Branch, Russia ); Hamann, W. -R. ( University of Potsdam, Institute of Physics and Astronomy, D-14476 Potsdam, Germany ); Buckley, D. ( Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Crause, L. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Crawford, S. M. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Gulbis, A. A. S. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Hettlage, C. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Hooper, E. ( Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706, USA ); Husser, T. -O. ( Institut für Astrophysik Georg-August-Universität, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany ); Kotze, P. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Loaring, N. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Nordsieck, K. H. ( Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706, USA ); O'Donoghue, D. ( Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Pickering, T. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Potter, S. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Romero-Colmenero, E. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Vaisanen, P. ( South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa; Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa ); Williams, T. ( Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854, USA ); Wolf, M. ( Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706, USA ) and 11 coauthors show affiliations
Monthly Notices of the Royal Astronomical Society, Volume 430, Issue 3, p.2302-2312
Published in Apr 2013
A considerable fraction of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient. Almost all of these H-deficient central stars (CSs) display spectra with strong carbon and helium lines. Most of them exhibit emission-line spectra resembling those of massive WC stars. Therefore these stars are classed as CSPNe of spectral type [WC]. Recently, quantitative spectral analysis of two emission-line CSs, PB 8 and IC 4663, revealed that these stars do not belong to the [WC] class. Instead PB 8 has been classified as [WN/WC] type and IC 4663 as [WN] type. In this work we report the spectroscopic identification of another rare [WN] star, the CS of Abell 48. We performed a spectral analysis of Abell 48 with the Potsdam Wolf-Rayet (PoWR) models for expanding atmospheres. We find that the expanding atmosphere of Abell 48 is mainly composed of helium (85 per cent by mass), hydrogen (10 per cent) and nitrogen (5 per cent). The residual hydrogen and the enhanced nitrogen abundance make this object different from the other [WN] star IC 4663. We discuss the possible origin of this atmospheric composition.
Keywords:
Free Keywords: Astrophysics - Solar and Stellar Astrophysics; planetary nebulae: general; planetary nebulae: individual: PN G029.0+00.4; stars: AGB and post-AGB; stars: Wolf-Rayet; stars: abundances; stars: mass-loss
Astronomy: planetary nebulae: general; planetary nebulae: individual: PN G029.0+00.4; stars: AGB and post-AGB; stars: Wolf-Rayet; stars: abundances; stars: mass-loss
arXiv: Astrophysics - Solar and Stellar Astrophysics
2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
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