SN 2009md: another faint supernova from a low-mass progenitor
2011 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 417, 1417-1433 p.Article in journal (Refereed) Published
We present adaptive optics imaging of the core-collapse supernova (SN) 2009md, which we use together with archival Hubble Space Telescope data to identify a coincident progenitor candidate. We find the progenitor to have an absolute magnitude of V=-4.63+0.3-0.4 mag and a colour of V-I= 2.29+0.25-0.39 mag, corresponding to a progenitor luminosity of log L/L&sun;˜ 4.54 ± 0.19 dex. Using the stellar evolution code STARS, we find this to be consistent with a red supergiant progenitor with M= 8.5+6.5-1.5 M&sun;. The photometric and spectroscopic evolution of SN 2009md is similar to that of the class of sub-luminous Type IIP SNe; in this paper we compare the evolution of SN 2009md primarily to that of the sub-luminous SN 2005cs. We estimate the mass of 56Ni ejected in the explosion to be (5.4 ± 1.3) × 10-3 M&sun; from the luminosity on the radioactive tail, which is in agreement with the low 56Ni masses estimated for other sub-luminous Type IIP SNe. From the light curve and spectra, we show the SN explosion had a lower energy and ejecta mass than the normal Type IIP SN 1999em. We discuss problems with stellar evolutionary models, and the discrepancy between low observed progenitor luminosities (log L/L&sun;˜4.3-5 dex) and model luminosities after the second dredge-up for stars in this mass range, and consider an enhanced carbon burning rate as a possible solution. In conclusion, SN 2009md is a faint SN arising from the collapse of a progenitor close to the lower mass limit for core collapse. This is now the third discovery of a low-mass progenitor star producing a low-energy explosion and low 56Ni ejected mass, which indicates that such events arise from the lowest end of the mass range that produces a core-collapse SN (7-8 M&sun;).
Place, publisher, year, edition, pages
2011. Vol. 417, 1417-1433 p.
stars: evolution, stars: massive, supernovae: general, supernovae: individual: SN 2009md, galaxies: individual: NGC 3389
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:su:diva-70080DOI: 10.1111/j.1365-2966.2011.19370.xISI: 000297043000040OAI: oai:DiVA.org:su-70080DiVA: diva2:479124
authorCount :242012-01-172012-01-172012-01-25Bibliographically approved