THE FAST AND FURIOUS DECAY OF THE PECULIAR TYPE Ic SUPERNOVA 2005ek

Journal Article · Sun Sep 01 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/774/1/58· OSTI ID:22133951

Drout, M. R.; Soderberg, A. M.; Margutti, R.; Milisavljevic, D.; Sanders, N. E.; Chornock, R.; Foley, R. J.; Kirshner, R. P.; Chakraborti, S.; Challis, P.; Friedman, A.; Hicken, M.; Jensen, C. ^[1]; Mazzali, P. A. ^[2]; Parrent, J. T. ^[3]; Filippenko, A. V.; Li, W.; Cenko, S. B.; Ganeshalingam, M. ^[4]; others, and

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Astrophysics Research Institute, Liverpool John Moores University, CH41 1LD Liverpool (United Kingdom)
3. Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States)
4. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

We present extensive multi-wavelength observations of the extremely rapidly declining Type Ic supernova (SN Ic), SN 2005ek. Reaching a peak magnitude of M{sub R} = -17.3 and decaying by {approx}3 mag in the first 15 days post-maximum, SN 2005ek is among the fastest Type I supernovae observed to date. The spectra of SN 2005ek closely resemble those of normal SN Ic, but with an accelerated evolution. There is evidence for the onset of nebular features at only nine days post-maximum. Spectroscopic modeling reveals an ejecta mass of {approx}0.3 M{sub Sun} that is dominated by oxygen ({approx}80%), while the pseudo-bolometric light curve is consistent with an explosion powered by {approx}0.03 M{sub Sun} of radioactive {sup 56}Ni. Although previous rapidly evolving events (e.g., SN 1885A, SN 1939B, SN 2002bj, SN 2010X) were hypothesized to be produced by the detonation of a helium shell on a white dwarf, oxygen-dominated ejecta are difficult to reconcile with this proposed mechanism. We find that the properties of SN 2005ek are consistent with either the edge-lit double detonation of a low-mass white dwarf or the iron-core collapse of a massive star, stripped by binary interaction. However, if we assume that the strong spectroscopic similarity of SN 2005ek to other SNe Ic is an indication of a similar progenitor channel, then a white-dwarf progenitor becomes very improbable. SN 2005ek may be one of the lowest mass stripped-envelope core-collapse explosions ever observed. We find that the rate of such rapidly declining Type I events is at least 1%-3% of the normal SN Ia rate.

• OSTI ID: 22133951
• Journal Information: Astrophysical Journal, Vol. 774, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BOLOMETERS
DECAY
EXPLOSIONS
GALACTIC EVOLUTION
HELIUM
IRON
NICKEL 56
OXYGEN
SIMULATION
SPECTROSCOPY
SUPERNOVAE
VISIBLE RADIATION
WAVELENGTHS
WHITE DWARF STARS