A Variety of Stellar Deaths: Connecting massive stars to a range of outcomes

1. A Variety of Stellar Deaths:Connecting massive stars to a range of outcomes Avishay Gal-Yam, Benoziyo Center for Astrophysics Weizmann Institute Jerusalem Winter School 2010

2. Metallicity Binarity Rotation … # of Events Initial mass The fate of massive stars Stability mass limit unclear: <7..11 solar; stable C/O core Electron Capture 7-11 Textbook view: Accreting C/O WDs (SNeIa) | Massive stars (SNeIb/c/II) | GRBs

3. Electron-capture supernovae? Electron-capture in ONeMg core by Mg 24 and Ne 20 (e.g., Nomoto 1984) SN 1998S; Spitzer May lead to low-energy, low-mass explosions (Crab SN?); SN 2008ha (Valenti et al. 2009; Foley et al. 2009) Possible explanation for low-luminosity nearby events (NGC 300 OT, SN 2008S; e.g., Thompson et al. 2008), dusty progenitors “smoking gun” signature still missing; Smith et al. 2009 promotes LBV explanation for all these events.

4. The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? Accretion-induced collapse M: 7-11

5. Accretion induced collapse (AIC) EC explosion in an old ONeMg WD following accretion (Nomoto 1984) Possible explanation for new class of SNe: Ca-rich faint SNe Ib (helium-rich, hydrogen-poor), provided donor is a He WD

6. Type Ib (UCB; CCCP) Graham & Li 2005 The Story of SN 2005E LOSS discovery Member of the Ca-rich Subclass (Filippenko et al.) Hagai Perets Dave Arnett, Paolo Mazzali, Daniel Kagan, UCB SN group, CCCP, Anderson & James, Ofek, Bildsten & Co., Quataert & Co.

7. SDSS The Story of SN 2005E (Cont.) CCCP2 follow-up shows … nothing SN 2005E exploded in a remote location, at the outskirts of an isolated, regular, edge-on S0/a galaxy ? A type Ib? How did the massive progenitor get there?

8. Local star formation? Not detected to deep limits … unlikely also on theoretical grounds r<25.3 (25.9) at 3(2)  Perets et al. 2009

9. 22.9 kpc 11.3 kpc A hyper-velocity SN (HVSN) ? Life in the fast lane? SN 2005E Not likely: chances to observe HVSNe with LOSS are < 1/100

10. A weird type Ia? Spectra conclusively rule out SN Ia identification No iron! Foley

11. Mazzali So what, then? What will nebular spectra reveal? Peculiar abundances (C, Ca, O, Ni56) = (0.1 0.135 0.037 0.003) solar Total ejected mass is ~0.3 solar ! (also fits light curve)

12. A new type of supernova Not a core collapse, nor SN Ia Perets et al. 2009

13. Not a single event! 6-10 additional siblings, additional early hosts SN 2007ke, LOSS

14. No SFR, hosts High velocities, nucleosynthesis } He accretion in a DD system What can it be? Possibilities reviewed by Foley, Valenti (for SN 2008ha): * Core collapse to a black hole (“failed SN”) * Weak/partial deflagration * AIC * “.Ia” Ofer Yaron

15. } Models by Arnett Nucleosynthesis Can you make so much Ca with no Si and S? (Ca/S >6) * No (if you burn C/O) * Yes (if you burn He) Need to burn He on a WD: DD system (Podsiadlowski) AIC (ONe+He WDs) and .Ia-like are possible models Work (theory and observation) is ongoing He/C/O accretion/merger result an emerging field

16. RSG=II-P Smartt M: 8-16 The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? AIC M: 7-11

17. Maund & Smartt 2009; Science Red Supergiants explode as SNe II-P As summarized recently by Smartt et al. * SNe II-P : most common SNe * Progenitors: M=8-17 solar RSGs * See Maund & Smartt 2009 for a robust observational result

18. Leonard et al. 2008; Crockett et al. in prep. Secure progenitor IDs * Lesson for observers: you really need HST/AO for secure association. Only post-SN imaging provides robust progenitor ID (87A, 05gl, 03gd, 93J) Nomoto et al. Kochanek et al. Hubble Survey

19. ? “The gap” The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P Smartt AIC M: 7-11 M: 8-16 M: 17-25

20. Pastorello et al. 2008 What happens around M~20? Smartt et al. (2008) * Apparent statistical dearth of massive RSG supernova progenitors >17 solar * ~20 Mo: other IIs (IIb SN 2008ax, Crockett et al. 2009, Pastorello et al. 2009; SN 1987A) * “The gap” – direct fallback to form black holes?

21. ? W-R = Ib/c? “The gap” “rare IIs”? The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P AIC M: 7-11 M: 8-16 M: 17-25 M: 25-30

22. What happens to massive W-R stars? * >25-30 Mo: should be Ib/c but unobserved so far (Maund et al. 2005; Gal-Yam et al. 2005; Crokett et al. 2009 …) * Trend suggests common Ic’s from low-mass binaries (Smartt et al. 08) * Conflict with Kelley et al., James & Anderson 2008, 2009? * Models suggest some SNe Ic may still leave behind a NS remnant (Mazzali)

23. NS BH ? W-R = Ib/c? “The gap” “rare IIs”? The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P HNe, GRB AIC M: 7-11 M: 8-16 M: 17-25 M: 25-30 M: 40-50

24. Soderberg et al. 2005 Long GRB – SN connection In all cases with good data, long GRBs come with SNe Ic with broad lines; Models give M=40-50 * WR “wind” profiles are rarely seen in model light curves or high-resolution spectroscopy * Environment indicates very massive, short-lived stars (Fruchter et al. 2006) * Low-Z massive WRs – single or binary?

25. NS BH ? W-R = Ib/c? “The gap” LBV=IIn “rare IIs”? M: 50-150 The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P HNe, GRB AIC M: 7-11 M: 8-16 M: 17-25 M: 25-30 M: 40-50

26. SNe IIn from very massive stars (LBVs) * Direct detection of the progenitor of SN 2005gl: L~106 solar Gal-Yam & Leonard 2009 Nature, April 22 * In accord with works by Kotak, Smith, Trundle, … * May involve the pulsational pair instability (PPSN; Woosley et al. 2007; Smith et al. 2009; Miller et al. 2009)

27. Galactic mass limit Figer (2005) NS BH ? W-R = Ib/c? “The gap” “rare IIs”? The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P HNe, GRB AIC LBV=IIn PI SNe M: 7-11 M: 8-16 M: 17-25 M: 25-30 M: 40-50 M: 50-150 M> 150

28. Pair Instability Supernovae (PISNE)(Barkat, Rakavi & Sack 1967 ; Heger & Woosley 2002; Waldman 2008 …) * Helium cores above ~50 solar masses become pair unstable * In these low-density high-T cores, e+e- wins over oxygen ignition, heat is converted to mass and implosion follows * Inertial oxygen ignition leads to explosion and full disruption Waldman * “This is a uniquely calculable process” (Heger & Woosley 2002); “this is a trivial calculation” (Barkat 2009); “Pretty neat homework problem” (Gal-Yam 1996) “Smoking gun”: Core mass > 50 solar

29. Pair Instability Supernovae (PISNE)(Barkat, Rakavi & Sack 1967 ; Heger & Woosley 2002; Waldman 2008 …) * Helium cores above the threshold robustly explode * PISNe care not for metallicity, but for mass loss * PISNe progenitors seem not to exist in our Galaxy – require M > 140 solar - (though transitional pulsational events might) * At early Universe, M~1000 stars may have existed

30. SN 2007bi=SNF20070406-008(PTF “dry run”) * Type Ic SN (no H, He). No interaction, no dust, v=12000 km/s * Luminous peak (-21.3), slow rise (~77 days), 56Co decay * M>3 solar masses of 56Ni, ejected mass ~100 solar, Ek~1e53 (scaling), 4-11 solar masses of 56Ni (87A) * Well-fit by models (Kasen) * Nebular spectra: 4-6 solar mass of 56Ni; >50 solar total (Mazzali), consistent with 98bw Core mass > 50 robustly established; Gal-Yam et al. 2009, also Young et al. 2009

31. Implications(Gal-Yam et al. 2009) * A helium core ~100 solar detected at Z ~ SMC * Mass loss models are wrong * PISNe happen locally, Universally, models are ~ok * Dwarfs have stars above Galactic limit (>200 solar, probably) * Hydrogen efficiently removed (pulsations?)

32. Physical parameters:

33. NS BH BH No remnant ? W-R = Ib/c? “The gap” “rare IIs”? The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P HNe, GRB AIC LBV=IIn PP SNe M: 7-11 M: 8-16 M: 17-25 M: 25-30 M: 40-50 M: 50-150 M> 150

34. PTF news … Pulsational pair SNe?

35. NS BH BH No remnant ? W-R = Ib/c? “The gap” “rare IIs”? The Core-Collapse Spectrum Lower mass limit unclear: <7..11 solar; stable C/O core EC SN? RSG=II-P HNe, GRB AIC LBV=IIn PP SNe M: 7-11 M: 8-16 M: 17-25 M: 25-30 M: 40-50 M: 50-150 M> 150

36. Thanks

37. Concept:SN 2007bi - “lessons”

38. Mass estimate confirmed by light curve analysis Perets et al. 2009 M ~ 0.3 solar