The binary progenitor of Tycho Brahe's 1572 supernova : Abstract : Nature

Nature 431, 1069-1072 (28 October 2004) | doi:10.1038/nature03006; Received 14 June 2004; Accepted 8 September 2004

The binary progenitor of Tycho Brahe's 1572 supernova

Pilar Ruiz-Lapuente^1,², Fernando Comeron³, Javier Méndez^1,⁴, Ramon Canal¹, Stephen J. Smartt⁵, Alexei V. Filippenko⁶, Robert L. Kurucz⁷, Ryan Chornock⁶, Ryan J. Foley⁶, Vallery Stanishev⁸ and Rodrigo Ibata⁹

Department of Astronomy, University of Barcelona, Marti i Franques 1, E-08028 Barcelona, Spain
Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85748 Garching, Germany
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany
Isaac Newton Group, PO Box 321, Santa Cruz de La Palma, Tenerife, Canary Islands, E-38780 Spain
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
Department of Astronomy, 601 Campbell Hall, University of California, Berkeley, California 94720-3411, USA
Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
Department of Physics, Stockholm University, AlbaNova University Center, SE-108 91 Stockholm, Sweden
Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France

Correspondence to: Pilar Ruiz-Lapuente^1,² Email: pilar@am.ub.es

The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion^1,^2,³. Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties. Tycho's supernova^4,⁵ is one of only two type Ia supernovae observed in our Galaxy, and so provides an opportunity to address observationally the identification of the surviving companion. Here we report a survey of the central region of its remnant, around the position of the explosion, which excludes red giants as the mass donor of the exploding white dwarf. We found a type G0–G2 star, similar to our Sun in surface temperature and luminosity (but lower surface gravity), moving at more than three times the mean velocity of the stars at that distance, which appears to be the surviving companion of the supernova.

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