A non-spherical core in the explosion of supernova SN 2004dj

Abstract

An important and perhaps critical clue to the mechanism driving the explosion of massive stars as supernovae is provided by the accumulating evidence for asymmetry in the explosion. Indirect evidence comes from high pulsar velocities, associations of supernovae with long-soft gamma-ray bursts, and asymmetries in late-time emission-line profiles. Spectropolarimetry provides a direct probe of young supernova geometry, with higher polarization generally indicating a greater departure from spherical symmetry. Large polarizations have been measured for 'stripped-envelope' (that is, type Ic) supernovae, which confirms their non-spherical morphology; but the explosions of massive stars with intact hydrogen envelopes (type II-P supernovae) have shown only weak polarizations at the early times observed. Here we report multi-epoch spectropolarimetry of a classic type II-P supernova that reveals the abrupt appearance of significant polarization when the inner core is first exposed in the thinning ejecta (~90 days after explosion). We infer a departure from spherical symmetry of at least 30 per cent for the inner ejecta. Combined with earlier results, this suggests that a strongly non-spherical explosion may be a generic feature of core-collapse supernovae of all types, where the asphericity in type II-P supernovae is cloaked at early times by the massive, opaque, hydrogen envelope.

Accepted for publication by Nature (results embargoed until 23 March 2006); 14 pages, 2 figures

References in corpus (1)

• Getting Its Kicks: A VLBA Parallax for the Hyperfast Pulsar B1508+55

Cited by in corpus (49)

• Spectropolarimetry of Supernovae
• Asphericity in Supernova Explosions from Late-Time Spectroscopy
• Dust and the type II-plateau supernova 2004et
• Multidimensional supernova simulations with approximative neutrino transport. II. Convection and the advective-acoustic cycle in the supernova core
• Features of the Acoustic Mechanism of Core-Collapse Supernova Explosions
• The explosion mechanism of core-collapse supernovae: progress in supernova theory and experiments
• The properties of the "standard" type Ic supernova 1994I from spectral models
• Multi-epoch spectropolarimetry of SN 2009ip: direct evidence for aspherical circumstellar material
• Spectropolarimetry of superluminous supernovae: insight into their geometry
• Spectropolarimetry of the Type Ib/c SN 2005bf
• Gravitational waves from 3D MHD core collapse simulations
• Time-dependent Effects in Photospheric-Phase Type II Supernova Spectra
• Asphericity, Interaction, and Dust in the Type II-P/II-L Supernova 2013ej in Messier 74
• The Dual-Axis Circumstellar Environment of the Type IIn Supernova 1997eg
• Spectropolarimetry of the Type IIb Supernova 2001ig
• The difficulty of inferring progenitor masses from Type II-Plateau supernova light curves
• The peculiar mass-loss history of SN 2014C as revealed through AMI radio observations
• After the Fall: Late-Time Spectroscopy of Type IIP Supernovae
• Time-resolved polarimetry of the superluminous SN 2015bn with the Nordic Optical Telescope
• The Plasma Structure of the Cygnus Loop from the Northeastern Rim to the Southwestern Rim
• Detection of optical linear polarization in the SN2006aj/XRF060218 non-spherical expansion
• Asymmetry of ${}^{56}$Ni ejecta and polarization in type IIP supernova 2004dj
• Photometric, polarimetric, and spectroscopic studies of the luminous, slow-decaying Type Ib SN 2012au
• Multi-Dimensional Simulations for Early Phase Spectra of Aspherical Hypernovae: SN 1998bw and Off-Axis Hypernovae
• Critical Surface for Explosions of Rotational Core-Collapse Supernovae
• SN2012ab: A Peculiar Type IIn Supernova with Aspherical Circumstellar Material
• Optical Spectropolarimetry and Asphericity of Type Ic SN 2007gr
• Properties of gamma-ray decay lines in 3D core-collapse supernova models, with application to SN 1987A and Cas A
• Luminosity distribution of Type II supernova progenitors
• Detailed X-Ray Mapping of the Shocked Ejecta and Circumstellar Medium in the Galactic Core-Collapse Supernova Remnant G292.0+1.8
• On the observational behaviour of the highly polarized Type IIn supernova SN 2017hcc
• A 3D Simulation of a Type II-P Supernova: from Core Bounce to Beyond Shock Breakout
• Three Dimensional Magnetohydrodynamical Simulations of Core Collapse Supernova
• Polarimetry of Hydrogen-Poor Superluminous Supernovae
• Evidence for multiple origins of fast declining Type II supernovae from spectropolarimetry of SN 2013ej and SN 2017ahn
• Late-Phase Spectropolarimetric Observations of Superluminous Supernova SN 2017egm to Probe the Geometry of the Inner Ejecta
• Oxygen and calcium nebular emission line relationships in core-collapse supernovae and Ca-rich transients
• Spectropolarimetry of Type II supernovae (II) Intrinsic supernova polarization and its relations with the photometric/spectroscopic properties
• The 3D shape of Type IIb SN 2011hs
• Broad band polarimetric follow-up of Type IIP SN 2012aw
• Circumstellar Light Echo as a Possible Origin of the Polarization of Type IIP Supernovae
• Optical polarimetric monitoring of the type II-plateau SN 2005af
• De-leptonization and Non-Axisymmetric Instabilities in Core Collapse Supernovae
• Observational properties of a Type Ib Supernova MASTER OT J120451.50+265946.6 in NGC 4080
• Spectropolarimetry of Type II supernovae (I) Sample, observational data and interstellar polarization
• SN 2016B a.k.a ASASSN-16ab: a transitional type II supernova
• PGIR 20eid (SN2020qmp): A Type IIP Supernova at 15.6 Mpc discovered by the Palomar Gattini-IR survey
• O/IR Polarimetry for the 2010 Decade (CGT): Science at the Edge, Sharp Tools for All
• Radiative-transfer modeling of supernovae in the nebular-phase. A novel treatment of chemical mixing in spherical symmetry