The progenitor of SN 2011ja

Clues from circumstellar interaction

Sayan Chakraborti, Alak Ray, Randall Smith, Stuart Ryder, Naveen Yadav, Firoza Sutaria, Vikram V. Dwarkadas, Poonam Chandra, David Pooley, Rupak Roy

Research output: Contribution to journalArticle

16 Citations (Scopus)


Massive stars, possibly red supergiants, which retain extended hydrogen envelopes until core collapse, produce Type II plateau (IIP) supernovae. The ejecta from these explosions shocks the circumstellar matter originating from the mass loss of the progenitor during the final phases of its life. This interaction accelerates particles to relativistic energies which then lose energy via synchrotron radiation in the shock-amplified magnetic fields and inverse Compton scattering against optical photons from the supernova. These processes produce different signatures in the radio and X-ray parts of the electromagnetic spectrum. Observed together, they allow us to break the degeneracy between shock acceleration and magnetic field amplification. In this work, we use X-rays observations from the Chandra and radio observations from the Australia Telescope Compact Array to study the relative importance of processes which accelerate particles and those which amplify magnetic fields in producing the non-thermal radiation from SN 2011ja. We use radio observations to constrain the explosion date. Multiple Chandra observations allow us to probe the history of variable mass loss from the progenitor. The ejecta expands into a low-density bubble followed by interaction with a higher density wind from a red supergiant consistent with M ZAMS ≳ 12 M . Our results suggest that a fraction of Type IIP supernovae may interact with circumstellar media set up by non-steady winds.

Original languageEnglish
Article number30
Number of pages8
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 1 Sep 2013
Externally publishedYes


  • circumstellar matter
  • radio continuum: general
  • shock waves
  • stars: mass-loss
  • supernovae: individual (SN 2011ja)
  • X-rays: general

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