DUSTY EXPLOSIONS FROM DUSTY PROGENITORS: THE PHYSICS OF SN 2008S AND THE 2008 NGC 300-OT
- Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus OH 43210 (United States)
SN 2008S and the 2008 NGC 300-OT were explosive transients of stars self-obscured by very dense, dusty stellar winds. An explosive transient with an unobserved shock breakout luminosity of order 10{sup 10} L{sub sun} is required to render the transients little obscured and visible in the optical at their peaks. Such a large breakout luminosity then implies that the progenitor stars were cool, red supergiants, most probably {approx}9 M{sub sun} extreme asymptotic giant branch stars. As the shocks generated by the explosions propagate outward through the dense wind, they produce a shock luminosity in soft X-rays that powers the long-lived luminosity of the transients. Unlike typical cases of transients exploding into a surrounding circumstellar medium, the progenitor winds in these systems are optically thick to soft X-rays, easily absorb radio emission, and rapidly reform dust destroyed by the peak luminosity of the transients. As a result, X-rays are absorbed by the gas and the energy is ultimately radiated by the reformed dust. Three years post-peak, both systems are still significantly more luminous than their progenitor stars, but they are again fully shrouded by the reformed dust and only visible in the mid-IR. The high luminosity and heavy obscuration may make it difficult to determine the survival of the progenitor stars for {approx}10 years. However, our model indicates that SN 2008S, but not the NGC 300-OT, should now be a detectable X-ray source. SN 2008S has a higher estimated shock velocity and a lower density wind, so the X-rays begin to escape at a much earlier phase.
- OSTI ID:
- 21612751
- Journal Information:
- Astrophysical Journal, Vol. 741, Issue 1; Other Information: DOI: 10.1088/0004-637X/741/1/37; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
COSMIC X-RAY SOURCES
DUSTS
EXPLOSIONS
LUMINOSITY
SOFT X RADIATION
STAR EVOLUTION
STELLAR WINDS
SUPERNOVAE
BINARY STARS
COSMIC RAY SOURCES
ELECTROMAGNETIC RADIATION
ERUPTIVE VARIABLE STARS
EVOLUTION
IONIZING RADIATIONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
STARS
STELLAR ACTIVITY
VARIABLE STARS
X RADIATION