The Red Supergiant Progenitors of Core-collapse Supernovae Justyn R. Maund Stellar Populations Workshop IAG-USP 1 st December 2015
Astronomy and Astrophysics at Sheffield 8 Academic staff 5 Postdocs 13 PhD students Massive Stars Supernovae Brown Dwarfs Instrumentation Star Formation Active Galactic Nuclei Time Domain
4 Hammer et al. Massive Stars t ~ Myrs Explosion Mechanism t ~ secs SN evolution t ~ kyrs FIG. 2. Surfaces of the radially outermost locations with constant mass fractions of 3% for carbon (green), and oxygen (red), and of 7% for nickel (blue). The upper two panels show the directional asymmetries from two different viewing directions at 350s after core bounce when the metal clumps begin to enter the helium layer of the star. The lower two panels display the hydrodynamic instabilities at about 9000s shortly after the supernova shock has broken out of the stellar surface. The side length of the upper panels is about 5 10 11 cm, of the lower panels 7.5 10 12 cm. act as seeds of secondary Rayleigh-Taylor instabilities at the composition interfaces of the exploding star. At about 100s dense Rayleigh-Taylor fingers containing the metals (C, O, Si, iron-group elements) have grown out of a compressed shell of matter left behind by the shock passing through the Si/O and (C+O)/He interfaces. These fingers grow quickly in length and while extending into the helium shell, fragment into ballistically moving clumps and filaments that propagate faster than the expansion of their environment. While for a 2D model with explosion energy around 1.8 10 51 erg the Si and Ni containing structures still move with nearly 4000kms -1 (oxygen has velocities up to even 5000kms -1 )at 300s, a strong deceleration occurs when the metal clumps enter the relatively dense He-shell that forms after the shock passage through the He/H interface. At t 10,000s the metal carrying clumps have dissipated their excess kinetic energy and propagate with the same speed as the helium material in their surroundings. In the presence of a hydrogen envelope and the corresponding deceleration of the shock as it propagates through the inner regions of the hydrogen layer (in which case the helium wall below the He/H interface builds up), Kifonidis et al. (2003) could not observe any metal clumps that achieve to penetrate into the hydrogen envelope, in contrast to what was observed in the case of SN 1987A. The 2D calculations performed in the course of the present work confirm these findings (when the velocities are appropriately rescaled with Eexp to account for the lower explosion energies of Eexp 10 51 erg considered here compared to roughly twice this value employed by Kifonidis et al. (2003). The evolution as well as the final results for the mass distributions of different chemical elements in velocity space and mass space are in good quantitative agreement with the mod-
WR stars RSGs Single star tracks - Cambridge STARS code, Eldridge & Tout (2004)
Direct detection in pre-explosion images Finding progenitors Ingredient #1: Fortuitous Pre-explosion Images Ingredient #2: High-Resolution Postexplosion Images Possible Differential with the astrometry advent of achieve public progenitor position to with a ~few 10s telescope milliarcseconds archives. Resolve Sources: individual Hubble stars or imaging out to 10Mpc or ground-based AO image (ground based) or 25Mpc (Hubble)
SN 2003gd SN 2003gd Van Dyk et al., 2003 Smartt, Maund et al., 2004, Science Pre-explosion WFPC2 F606W and Gemini i -> V-I colour Assume reddening is same as for nearby stars (main sequence) Determine star s properties from just a handful of broad-band photometric points in case of non-detection only upper limits
Disappearance = confirmation SN 2003gd ~8M Maund & Smartt, 2009, Science Gemini GMOS i image Late-time observations ~5 years post-explosion
Compare observed luminosity with the final luminosities predicted for stars with a given initial mass If no detection, use detection limits to place upper luminosity limit Take mass estimate to be between onset of He burning and the model end point
End of model End of core-he burning Smartt et al. 2009 : initial masses are quoted with Gaussian uncertainties Maund et al., 2014a,b, 2015a,b: quote initial mass as combination of pdfs (luminosity convolved with mass range)
Ruling out S-AGB progenitors Low luminosity SNe don t necessarily have to come from EC- SNe Deep NIR imaging limits on the progenitor of SN 2005cs, exclude S-AGB end points (through comparison with MARCS Teff vs E(B-V) HRD Mass PDF models) Maund et al., 2014a
How much dust affects progenitors? Fit the SED (optical and IR) of SN 2012aw, assuming RV = 3.1 large range in T and E(B-V) (degeneracy) could this be a low mass progenitor or high mass but extinguished No evidence of high levels of A V in SN spectra could dust be CSM Fraser et al, 2012; Van Dyk et al, 2012
SN 2008bk the best progenitor detection* Progenitor detected in 8 photometric bands (g r i IYJHK) 2 upper limits(bv) Maund et al., 2013 Mattila et al., 2008 (IJHK) Van Dyk et al., 2012 (g r i JHK) Confirmed to have disappeared (Mattila et al., 2011) Determine parameters with respect to MARCS synthetic spectra *Since SN 1987A
SN 2008bk Highly reddened, higher temperature(!!!) progenitor than normally expect most precise mass derived for a progenitor so far, with systematics understood. Late-time observations taken under excellent seeing and photometric conditions (independent calibration)
500R 1100R Davies et al. (2013) Xshooter observations of SMC and LMC RSGs Dessart et al. (2013) smaller progenitor radii required to match early UV light curve for Type IIP SNe Results from new progenitor analysis simultaneously match observed properties of RSGs and requirements for Type IIP SNe suggest stellar evolution models need a tweak SED models give us T bolometric correction the SED is what we care about (ATLAS9 and MARCS models give similar results). The progenitor of SN 2008bk has the colours of a K-supergiant (have we previously made wrong assumptions for
JWST The unknown amount of CSM dust and the temperature scale for RSG progenitors are a big unknown Move further into the IR!!! JWST NIRCAM observations can rival HST spatial resolution F444W (4μm) filter pretty much insensitive to dust and the bolometric correction changes only marginally over the expected temperature range for RSGs (3000-5000K) Expect RSG progenitors in the range log(l/l )=4.0 5.5 1000s exposure with JWST in F444W will give a 5σ detection for the faintest RSG that can explode as a SN out to 25Mpc
The Type IIb SN 1993J Second closest SN in modern era (M81) Second ever progenitor ID Simultaneously blue + red SED K-supergiant not M-supergiant progenitor Peculiar double peaked light curve Changed from H-rich Type II to H- poor Type Ib Aldering et al., 1994, AJ, 107, 662
A binary progenitor system Late-time spectroscopy revealed B-supergiant companion in fading remnant of the Type IIb SN1993J hence confirming the binary progenitor scenario, and peculiar observed colors of the progenitor in preexplosion images. 1 Night with Keck, just get absorption lines from a star with m B ~22 at 3Mpc Maund et al., 2004, Nature, 427, 129 Van Dyk et al., 2002, PASP
Spectroscopy with the E-ELT With E-ELT+MOSAIC can conduct spectroscopy of stars out to ~35Mpc Instead of fortuitous preexplosion images, could we have a high-s/n, high-resolution spectrum of the progenitor of a SC5: Resolved stellar populations future beyond SN? the Local