• DOI:10.1088/0004-637X/714/2/1209
• Corpus ID: 13990681

SPECTROPOLARIMETRY OF EXTREMELY LUMINOUS TYPE Ia SUPERNOVA 2009dc: NEARLY SPHERICAL EXPLOSION OF SUPER-CHANDRASEKHAR MASS WHITE DWARF

@article{Tanaka2009SPECTROPOLARIMETRYOE,
  title={SPECTROPOLARIMETRY OF EXTREMELY LUMINOUS TYPE Ia SUPERNOVA 2009dc: NEARLY SPHERICAL EXPLOSION OF SUPER-CHANDRASEKHAR MASS WHITE DWARF},
  author={Masaomi Tanaka and Koji S. Kawabata and Masayuki Yamanaka and Kei-ichi Maeda and Takashi Hattori and Kentaro Aoki and Ken’ichi Nomoto and Masanori Iye and Toshiyuki Sasaki and Paolo A. Mazzali and Elena Pian},
  journal={The Astrophysical Journal},
  year={2009},
  volume={714},
  pages={1209 - 1216}
}

• Masaomi Tanaka, K. Kawabata, +8 authors E. Pian
• Published 14 August 2009
• Physics
• The Astrophysical Journal

We present the first spectropolarimetric observations of a candidate of super-Chandrasekhar mass Type Ia supernova (SN): SN 2009dc. The observations were performed at 5.6 and 89.5 days after the B-band maximum. The data taken at the later epoch are used to determine the interstellar polarization. Continuum polarization is found to be small (<0.3%), indicating that the explosion is nearly spherically symmetric. This fact suggests that a very aspherical explosion is not a likely scenario for SN 2009dc. Polarization at the Si ii and Ca ii lines clearly shows a loop in the Q–U plane, indicating a non-axisymmetric, clumpy distribution of intermediate-mass elements. The degree of line polarization at the Si and Ca lines is moderate (0.5% ±  0.1% and 0.7% ±  0.1%, respectively), but it is higher than expected from the trend of other Type Ia SNe. This may suggest that there are thick enough, clumpy Si-rich layers above the thick 56Ni-rich layers (≳1.2 M☉). The observed spectropolarimetric properties, combined with the photometric and spectroscopic properties, suggest that the progenitor of SN 2009dc has a super-Chandrasekhar mass, and that the explosion geometry is globally spherically symmetric, with clumpy distribution of intermediate-mass elements.