Comparison of progenitor mass estimates for the Type IIP SN 2012A

We present the one-year long observing campaign of SN 2012A which exploded in the nearby (9.8 Mpc) irregular galaxy NGC 3239. The photometric evolution is that of a normal Type IIP supernova, but the plateau is shorter and the luminosity not as constant as in other supernovae of this type. The absol...

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Veröffentlicht in:Monthly notices of the Royal Astronomical Society 2013, Vol.434 (2), p.1636-1657
Hauptverfasser: Tomasella, L., Cappellaro, E., Fraser, M., Pumo, M. L., Pastorello, A., Pignata, G., Benetti, S., Bufano, F., Dennefeld, M., Harutyunyan, A., Iijima, T., Jerkstrand, A., Kankare, E., Kotak, R., Magill, L., Nascimbeni, V., Ochner, P., Siviero, A., Smartt, S., Sollerman, J., Stanishev, V., Taddia, F., Taubenberger, S., Turatto, M., Valenti, S., Wright, D. E., Zampieri, L.
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Sprache:eng
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Zusammenfassung:We present the one-year long observing campaign of SN 2012A which exploded in the nearby (9.8 Mpc) irregular galaxy NGC 3239. The photometric evolution is that of a normal Type IIP supernova, but the plateau is shorter and the luminosity not as constant as in other supernovae of this type. The absolute maximum magnitude, with M B = −16.23 ± 0.16 mag, is close to the average for SN IIP. Thanks also to the strong UV flux in the early phase, SN 2012A reached a peak luminosity of about 2 × 1042 erg s−1, which is brighter than those of other SNe with a similar 56Ni mass. The latter was estimated from the luminosity in the exponential tail of the light curve and found to be M(56Ni) = 0.011 ± 0.004 M, which is intermediate between standard and faint SN IIP. The spectral evolution of SN 2012A is also typical of SN IIP, from the early spectra dominated by a blue continuum and very broad (∼104 km s−1) Balmer lines, to the late-photospheric spectra characterized by prominent P-Cygni features of metal lines (Fe ii, Sc ii, Ba ii, Ti ii, Ca ii, Na i D). The photospheric velocity is moderately low, ∼3 × 103 km s−1 at 50 d, for the low optical depth metal lines. The nebular spectrum obtained 394 d after the shock breakout shows the typical features of SNe IIP and the strength of the [O i] doublet suggests a progenitor of intermediate mass, similar to SN 2004et (∼15 M). A candidate progenitor for SN 2012A has been identified in deep, pre-explosion K ′-band Gemini North Near-InfraRed Imager and Spectrometer images, and found to be consistent with a star with a bolometric magnitude −7.08 ± 0.36 (log L/L = 4.73 ± 0.14 dex). The magnitude of the recovered progenitor in archival images points towards a moderate-mass star as the precursor of SN 2012A. The explosion parameters and progenitor mass were also estimated by means of a hydrodynamical model, fitting the bolometric light curve, the velocity and the temperature evolution. We found a best fit for a kinetic energy of 0.48 foe, an initial radius of 1.8 × 1013 cm and ejecta mass of 12.5 M. Even including the mass for the compact remnant, this appears fully consistent with the direct measurements given above.
ISSN:0035-8711
1365-2966
1365-2966
DOI:10.1093/mnras/stt1130