SN 2009js AT THE CROSSROADS BETWEEN NORMAL AND SUBLUMINOUS TYPE IIP SUPERNOVAE: OPTICAL AND MID-INFRARED EVOLUTION
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
- Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)
- National Astronomical Observatory, Mitaka, Tokyo (Japan)
- Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa (Japan)
- Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
- European Southern Observatory, Alonso de Cordova 3107, Santiago 19 (Chile)
- Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States)
- Department of Astronomy, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)
We present a study of SN 2009js in NGC 918. Multi-band Kanata optical photometry covering the first {approx}120 days shows the source to be a Type IIP SN. Reddening is dominated by that due to our Galaxy. One-year-post-explosion photometry with the New Technology Telescope and a Subaru optical spectrum 16 days post-discovery both imply a good match with the well-studied subluminous SN 2005cs. The plateau-phase luminosity of SN 2009js and its plateau duration are more similar to the intermediate luminosity IIP SN 2008in. Thus, SN 2009js shares characteristics with both subluminous and intermediate luminosity supernovae (SNe). Its radioactive tail luminosity lies between SN 2005cs and SN 2008in, whereas its quasi-bolometric luminosity decline from peak to plateau (quantified by a newly defined parameter {Delta}logL, which measures adiabatic cooling following shock breakout) is much smaller than both the others'. We estimate the ejected mass of {sup 56}Ni to be low ({approx}0.007 M{sub Sun }). The SN explosion energy appears to have been small, similar to that of SN 2005cs. SN 2009js is the first subluminous SN IIP to be studied in the mid-infrared. It was serendipitously caught by Spitzer at very early times. In addition, it was detected by WISE 105 days later with a significant 4.6 {mu}m flux excess above the photosphere. The infrared excess luminosity relative to the photosphere is clearly smaller than that of SN 2004dj, which has been extensively studied in the mid-infrared. The excess may be tentatively assigned to heated dust with mass {approx}3 Multiplication-Sign 10{sup -5} M{sub Sun }, or to CO fundamental emission as a precursor to dust formation.
- OSTI ID:
- 22126883
- Journal Information:
- Astrophysical Journal, Vol. 767, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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