The Necklace: equatorial and polar outflows from the binary central star of the new planetary nebula IPHASX J194359.5+170901

Authors

  • R. L. M. Corradi,

    Corresponding author
    1. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
    2. Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
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  • L. Sabin,

    1. Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 877, 22800 Ensenada, B.C., Mexico
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  • B. Miszalski,

    1. Centre for Astrophysics Research, STRI, University of Hertfordshire, College Lane Campus, Hatfield AL10 9AB
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  • P. Rodríguez-Gil,

    1. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
    2. Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
    3. Isaac Newton Group of Telescopes, Apart. de Correos 321, 38700 Santa Cruz de la Palma, Spain
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  • M. Santander-García,

    1. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
    2. Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
    3. Isaac Newton Group of Telescopes, Apart. de Correos 321, 38700 Santa Cruz de la Palma, Spain
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  • D. Jones,

    1. Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL
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  • J. E. Drew,

    1. Centre for Astrophysics Research, STRI, University of Hertfordshire, College Lane Campus, Hatfield AL10 9AB
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  • A. Mampaso,

    1. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
    2. Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
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  • M. J. Barlow,

    1. Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT
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  • M. M. Rubio-Díez,

    1. Isaac Newton Group of Telescopes, Apart. de Correos 321, 38700 Santa Cruz de la Palma, Spain
    2. Centro de Astrobiología, CSIC-INTA, Ctra de Torrejón a Ajalvir km 4, E-28850 Torrejón de Ardoz, Spain
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  • J. Casares,

    1. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
    2. Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
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  • K. Viironen,

    1. Centro Astronómico Hispano Alemán, Calar Alto, C/Jesús Durbán Remón 2-2, E-04004 Almeria, Spain
    2. Centro de Estudios de Física del Cosmos de Aragón (CEFCA), C/General Pizarro 1-1, E-44001 Teruel, Spain
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  • D. J. Frew,

    1. Department of Physics and Astronomy, Macquarie University, North Ryde, NSW 2109, Australia
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  • C. Giammanco,

    1. Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
    2. Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
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  • R. Greimel,

    1. Institut für Physik, Karl-Franzen Universität Graz, Universitätsplatz 5, 8010 Graz, Austria
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  • S. E. Sale

    1. Dept. de Física y Astronomía, Universidad de Valparaíso, Ave. Gran Bretaa 1111, Playa Ancha, Casilla 53,Valparaíso, Chile
    2. Dept. de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Casilla 306, Santiago 22, Chile
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E-mail: rcorradi@iac.es

ABSTRACT

IPHASX J194359.5+170901 is a new high-excitation planetary nebula with remarkable characteristics. It consists of a knotty ring expanding at a speed of 28 km s−1, and a fast collimated outflow in the form of faint lobes and caps along the direction perpendicular to the ring. The expansion speed of the polar caps is ∼100 km s−1, and their kinematical age is twice as large as the age of the ring.

Time-resolved photometry of the central star of IPHASX J194359.5+170901 reveals a sinusoidal modulation with a period of 1.16 d. This is interpreted as evidence for binarity of the central star, the brightness variations being related to the orbital motion of an irradiated companion. This is supported by the spectrum of the central star in the visible range, which appears to be dominated by emission from the irradiated zone, consisting of a warm (6000–7000 K) continuum, narrow C iii, C iv and N iii emission lines, and broader lines from a flat H i Balmer sequence in emission.

IPHASX J194359.5+170901 helps to clarify the role of (close) binaries in the formation and shaping of planetary nebulae (PNe). The output of the common-envelope (CE) evolution of the system is a strongly flattened circumstellar mass deposition, a feature that seems to be distinctive of this kind of binary system. Also, IPHASX J194359.5+170901 is among the first post-CE PNe for which the existence of a high-velocity polar outflow has been demonstrated. Its kinematical age might indicate that the polar outflow is formed before the CE phase. This points to mass transfer on to the secondary as the origin, but alternative explanations are also considered.

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