1. NGC 2419 – the most bizarre Galactic globular cluster Judith Cohen (Caltech) & Evan Kirby (UC Irvine/Caltech) Conference: Small Stellar Systems, Tuscany, Italy June 2013

2. Nucleosynthesis of elements  ow to use chemical inventory to infer GC history  -elements, abundant, N 4 He, SNII Light elements C,N,O,Na,Mg,Al,(Si) AGB stars /rapidly rotating massive stars Fe-peak elements SNIa Heavy neutron capture elements (Sr,Y,Zr vs Ba….Eu..Dy) r (SNII) and s(AGB)

3. Multiple Stellar Generations Variations of He,C,N,O,Na,Mg,Al, (Si) do NOT require SN contribution after initial burst Variations of heavier elements up to end of Fe-peak DO require additional SN input Variations of s-process n-capture elements do NOT require additional SN input Variations of r-process n-capture elements DO require additional SN input

4. NGC 2419 (Cohen & Kirby) ~85 kpc from Sun at b = 25.2 deg Luminous cluster M V -9.6 mag, most luminous of all GCs with R > 20 kpc, of all R > 15 kpc except for M54 Largest core and half light radius of any GC in the outer halo of the Milky Way HST imaging – no evidence for a spread in age/metallicity, but does have an extremely blue extension of the HB (Di Criscienzo et al, 2012)

5. R(h) vs M_V, ( Van den Bergh & Mackey, 2005)

6. NGC 2419: Anomaly is in L, not in R(h) (McLaughlin 2000)

7. Deimos GC Project of Cohen & Kirby Clusters checked with Deimos spectra (mod res, 6000 to 10,000 A) NGC 2419, NGC 4590 (M68), NGC 5024 (M53), NGC 5053, NGC 5634, NGC 5904 (M5), NGC 6205 (M13), NGC 6229, NGC 6341 (M92), NGC 6656 (M22), NGC 6838 (M71), NGC 7006, NGC 7078 (M15), NGC 7089 (M2) Only NGC 2419 and M22 (M V -8.50) show signs of a spread in Ca/H. M22 is most obvious of the 2.

8. M15, NGC 2419, M5 Deimos CaT vs V-V(HB)

9. NGC 2419 new HIRES sample on Ca/H histogram

10. NGC 2419 Cohen Kirby abundances vs V mag

11. NGC 2419 Cohen & Kirby 2013 normal Mg/Blue, low Mg/red

12. NGC 2419 Cohen & Kirby 2013 normal Mg/blue, low Mg/red

13. NGC 2419 Ca/H (HIRES) vs Ca/H(CaT Deimos)

14. Summed spectra of Mg-poor (blue) and Mg-rich (red)

15. Summed spectra NGC 2419 RGB Mg-poor/rich

16. Summed spectra NGC 2419, Mg poor/rich

17. Summed spectra: Mg-normal blue, Mg-poor red

18. Trends with [Na/Fe] in NGC 2419 HIRES sample

19. Status – NGC 2419 NGC 2419 unique and bizarre, showing a normal metal-poor GC population plus one with Mg, K Sc, and modest Ca enhancement. Fe range is not detected. Ventura et al (2013): HBB in unusually massive AGB stars maybe can do this – not easily though. Need T > 10 8 requires M ~ 6 Msun. Test: C and especially O abundances

20. NEW: Carbon abundances (Deimos/Keck, Cohen)

21. NEW: [C/Fe] vs V (Deimos/Keck: Kirby)

22. M13 [C/Fe] vs V. v line=RGB bump, tip~12.2, MSTO ~ 18.5 Briley, Cohen, Harbeck 2008, never published

23. NEW: [C/Fe] vs V (Deimos/Keck)

24. NEW: Carbon abundances Deimos/Keck

25. Summary Many GCs show no evidence for a range in heavy elements (Ca,Fe peak) - would require SN contribution Essentially all show well known correlations among light elements AGB or rapidly rotating massive stars Some of these show associated s-process enhancements Only M92 shows enhanced r-process Most massive often show range of Ca, Fe, etc and are probably remnants of accreted satellites with more complex extended star formation history than in normal GCs.

26. Today: NGC 2419 still unique C/Fe appears normal for a GC (trend with M_V and spread at a given M_V) Possible that Mg-poor stars have slightly higher mean [C/Fe] than Mg-normal Mean difference in [C/Fe] vs V is only ~0.2 dex. Working towards O abundances, soon…

27. Small Stellar Systems, June 2013, Tuscany, Italy BACKUP SLIDES

28. NGC 2419 red [Mg/Fe] 0 iso. 12 Gyr, [Fe/H] - 2.2, -1.9

29. Mg e - donor. Impact of change in Mg on atmos- phere shown here, also impact on CMD.

30. Diagnostic diagrams of abund vs V mag and of ion eq for Fe and for Ti HIRES sample NGC 2419 13 RGB stars

31. NGC 2419 Spatial distribution (high Ca - red)

32. NGC 2419 – emission in wings of H  indicator of extended atmosphere, mass loss, chromosphere

33. NGC 2419 summed spectra, no sign of Li 6707

34. C depletion vs age in Myr with 0.0 = RGB tip (M13 filled, M15 open, RGB bump to tip), f 0.023 (0.035) dex/Myr

35. M92 rare earths, abundances are constant Cohen, 2011, ApJL,  =0.06 to 0.07 dex for Fe, Y, Ba, La, and Eu/Fe

36. M15 r- process, rare earths are r-proc, with X/Fe varying by factor of 6 ! J.Cohen, 2008, never published

37. M15 – compare [X/Fe](obs) vs s-process ratios. Not s- process !

38. No detectable range in Fe/H within 19 GCs, UVES (high res, few stars) & Giraffe (mod res, many stars) Carretta et al (2000)

39. Ca/H distribution from RGBs in 19 GCs show no detectable range within a GC Carretta et al (2001)

40. Internal range in Fe seems to be confined to the most massive (as seen today) GCs (Carretta et al 2010)

41. NGC 1851, Yong et al, Carretta et al, 2011 M V -8.33 mag

42. NGC 1851, high Fe/H = high Ba/H, s-process, Yong et al, Carretta et al (2011)

43. NGC 1851 (Carretta et al), M5 & M4 (Ivans et al), Ba/Eu ratio implies s-process enhancement

44. M71 precision abunds (Melendez& Cohen 2008)

45. M71 Mg isotopic ratios, s-process, Melendez & Cohen (2008)

46. M71 Note v low  in X/Fe for all except La/Fe