Faint Supernova or Super-AGB star?: SN 2008S in context

Margaret Meixner STScIMasaaki Otsuka STScI/ASIAA

David Riebel JHUSEEDS consortium

SN2008S: Spitzer IRAC 3.6 micron

Wesson et al. (2009)

Day 17 Day 180

WHIRC (WIYN High Resolution InfraRed Camera) field: SN 2008S & SN 2002hh

Otsuka et al. submitted

SEEDS: The Search for Evolution of Emission from Dust in Supernovae

• Science Goal is to quantify the rate of dust production in Type-II SNe

• Track Type-II SNe light curves to very late times and look for simultaneous 3 observational signatures:– Sudden dimming of optical light (HST)– Brightening of mid-IR light (Spitzer)– Blue shifting of spectral lines (Hα, Gemini GMOS)

SN2008S Near-IR light curve

Otsuka et al. submitted

Otsuka et al. submitted

SN2008S Near-IR light curve

Otsuka et al. submitted

SN2008S Near-IR light curve

SN2008S: a faint supernova?

Otsuka et al. submitted

SEEDS sample & progenitor mass

SEEDS sample & light echo

SEEDS sample & dust production

SN2008S: a Super-AGB star? comparison to AGB stars in LMC

Riebel & Meixner 2011

Riebel & Meixner 2011

SN2008S: a Super-AGB star? comparison to AGB stars in LMC

SN2008S: Progenitor SED model carbon rich super-AGB star

Wesson et al. (2009)

Silicates

Amorphouscarbon

T~380 KL~3.2×104 LM~10 MMloss~5x10-7 M yr-1

Mtot ~0.01 M

SN 2008S illumination

Wesson et al. (2009)

Day 17

Day 180

SN2008S: Day 17 SED

Wesson et al. (2009)

T~550 KL~2.2×106 LLTOT~1.5×107 L

Amorphouscarbon

SN2008S: Day 180 SED

Wesson et al. (2009)

T~450 KL~3.6×105 LLTOT~1.2×106 L

Amorphouscarbon

Stellar Sources of Dust: Massive Stars

March 2011 Herschel & Characteristics of Dust in Galaxies - Meixner

Object classProgenitormass

Example sources

Dust Mass (M or Myr-1)

Dust composition

Gas-to-dust ratio/refs

Supernovae SN 2002hhSN 2003gdSN 2004etSN 2007itSN 1987A

0.1 <0.02 1.5×10-3

<10-4

~0.7

Amorphous silicates?,Amorphous carbon?

Barlow et al. 2002Sugerman et al. 2006Fabbri et al. 2011, sub.Andrews et al. 2011Otsuka et al. 2011, sub.Matsuura et al. 2011, acc.

Red Super Giant, 8-40 M

BetelgeuseMuCephVYCMaNML Cyg

3-10×10-10 5-8×10-9 1×10-6

6×10-6

Metal Oxides,Amorphous silicates,Metallic iron?

Verhoelst et al. 2009De Wit et al. 2008

Asymptotic Giant Branch stars, carbon rich, 2-4 M

VHyaIRC+10216AFGL 3068SN2008S?

2×10-9

2×10-8

1.6×10-7

5×10-7

Amorphous carbon, PAHs,MgS, SiC

700 Groenewegen 1998Jura 1986Jura & Kleinman 1989Wesson et al. 2009

Asymptotic Giant Branch stars, oxygen rich 0.8-2; 4-8 M

MiraW HyaRX BooOH 44.8-2.3OH 26.5+0.6

5.5×10-10

2×10-9

2×10-9

2.8×10-7

1.2×10-6

Silicates, amorphous & crystalline

280De Beck et al. 2010

Conclusions: SN 2008S• Most likely a Super-AGB star

– T~380 K– L~3.2×104 L

– M~10 M

– Mloss~5x10-7 M yr-1

– Mtot ~0.01 M (2x104 yr)

• Carbon rich circumstellar dust, interesting, unusual• Significant dust contributor in galaxies:

– Dust produced in “pre-explosion” phase– Massive enough could evolve fast enough to be important in early universe– May not destroy its own dust as with SNe

• Important to keep monitoring this field to see if we recover a progenitor