An asymmetric explosion as the origin of spectral evolution diversity in type Ia supernovae

TY - JOUR

T1 - An asymmetric explosion as the origin of spectral evolution diversity in type Ia supernovae

AU - Maeda...[et al.], K.

AU - Benetti, S.

AU - Stritzinger, Maximilian David

AU - Roepke, F. K.

AU - Folatelli, G.

AU - Sollerman, Jesper Olof

PY - 2010/7/1

Y1 - 2010/7/1

N2 - Type Ia supernovae form an observationally uniform class of stellar explosions, in that more luminous objects have smaller decline-rates. This one-parameter behaviour allows type Ia supernovae to be calibrated as cosmological ĝ€̃ standard candlesĝ€™, and led to the discovery of an accelerating Universe. Recent investigations, however, have revealed that the true nature of type Ia supernovae is more complicated. Theoretically, it has been suggested that the initial thermonuclear sparks are ignited at an offset from the centre of the white-dwarf progenitor, possibly as a result of convection before the explosion. Observationally, the diversity seen in the spectral evolution of type Ia supernovae beyond the luminosity-decline- rate relation is an unresolved issue. Here we report that the spectral diversity is a consequence of random directions from which an asymmetric explosion is viewed. Our findings suggest that the spectral evolution diversity is no longer a concern when using type Ia supernovae as cosmological standard candles. Furthermore, this indicates that ignition at an offset from the centre is a generic feature of type Ia supernovae.

AB - Type Ia supernovae form an observationally uniform class of stellar explosions, in that more luminous objects have smaller decline-rates. This one-parameter behaviour allows type Ia supernovae to be calibrated as cosmological ĝ€̃ standard candlesĝ€™, and led to the discovery of an accelerating Universe. Recent investigations, however, have revealed that the true nature of type Ia supernovae is more complicated. Theoretically, it has been suggested that the initial thermonuclear sparks are ignited at an offset from the centre of the white-dwarf progenitor, possibly as a result of convection before the explosion. Observationally, the diversity seen in the spectral evolution of type Ia supernovae beyond the luminosity-decline- rate relation is an unresolved issue. Here we report that the spectral diversity is a consequence of random directions from which an asymmetric explosion is viewed. Our findings suggest that the spectral evolution diversity is no longer a concern when using type Ia supernovae as cosmological standard candles. Furthermore, this indicates that ignition at an offset from the centre is a generic feature of type Ia supernovae.

U2 - 10.1038/nature09122

DO - 10.1038/nature09122

M3 - Journal article

C2 - 20596015

SN - 0028-0836

VL - 466

SP - 82

EP - 85

JO - Nature

JF - Nature

IS - 7302

ER -