1. Stellar Astrophysics: Things That Are Too Hard for Keck Judy Cohen (Caltech)+ Evan Kirby, the 0Z team and Branimir Sesar Astronomy in the TMT Era Tokyo, Oct 2013 1

2. Four Problems Gravitational settling in the Sun & solar modeling Extremely metal-poor stars: CNO Chemical Evolution in Nearby Galaxies The total mass of the Milky Way + finding more ultra-faint galaxies – RR Lyr + HSC/Subaru 1

3. M13 HB, grav settling, rad levitation Behr, Cohen + 2

4. Vrot vs Teff, M13 HB, vrot drops rapidly as Teff up Behr, Cohen, +, ~2000, big effect ! 3

5. Richard, Michaud et al predict diffusion in low Fe/H dwarfs Size of effect reduced in response to our and others early work. 4

6. M92 CMD + HIRES sample, reaches MSTO 5

7. M92 [Fe/H] vs Teff, upper RGB to MSTO, HIRES 6

8. M92, same for Ti12, can’t achieve needed accuracy, spent > 4 HIRES/Keck nights on MSTO. HIRES with multiplex would be great ! 7

9. 0Z project, 122 EMP/HES, [C(CH)/Fe] vs [Fe/H] 8

10. Adding N and O C from 4300 strong CH band. N,O not so easy N from NH band, 3360 A O from OH bands, 3200 A or near 1.6 microns Weak lines, in regions hard to observe Really need full set of CNO abundances for best understanding 9

11. 122 EMP stars, HES 0Z, new class found: low-Ca stars 10

12. Chemical Evolution of the Local Group, Kirby, Cohen + many, Deimos/Keck 2850 RGB stars in 8 dSph MW satellites, most distant Leo I at 260 kpc 108 stars in 7 Ultra-Faint MW satellites, most distant CVnII at 160 kpc 629 in 7 Local Group isolated dIrr, most distant VV 124 at 1,400 kpc 11

13. Kirby et al Local Group Sample 12

14. Sculptor, 375 RGB stars, ~100/slitmask 13

15. [Fe/H] distributions, 7 isolated dIrr 14

16. MDF for 4 most luminous dSph 15

17. vs Luminosity. All Deimos. 16

18. Now add in SDSS data, vs M(star) 17

19. Combined MDF for luminous dSph and dIrr 18

20. CMD Segue 2 SDSS, not many stars bright enough 19

21. ACS CMDs for nearby UF galaxies Brown et al 2013 20

22. WTPC2/HST Leo T (415 kpc) Clementini et al 2013 21

23. We are now at the limit of Keck Can’t do ultra-faints better – very few bright giants and can’t reach more numerous MS No group has had success in finding more UF, PanStars none so far, PTF not suitable for this Kirby, Cohen + no more MW satellites left close enough for Deimos 22

24. RR Lyr: Total Mass of the Milky Way with dark matter, and finding more UF MW satellites RR Lyrae can be found in the PTF to ~100 kpc A period + a rough Fe/H determines an accurate luminosity and distance We have found ~100 RR Lyr at 70 < D < 100 kpc excluding more than 100 in the known dSph, with vr can infer total mass of MW out to 100 kpc. Using RR Lyr as lamp-posts can we find the very low luminosity stellar systems/streams in which they presumably live ? 23

25. Palomar Transient Factory RR Lyrae Stars (~900 RR Lyr 30 < R < 100 kpc) Se~~ RR Lyrae stars between 70 and 100 kpc

26. 8 RR Lyrae Stars at ~85 kpc in 45 deg 2

27. RR Ly 70-100 kpc (~90 in Draco dSph) 26

28. Histogram – distances of outer halo RR Lyr, excludes RR Lyr in known MW satellites 27

29. How to get beyond 100 kpc – HSC !! Find the RR Lyr using HSC wide survey Get periods using Keck (cadence project) Get vr + rough Fe/H using Keck Use known RR Lyr distance + matched filter algorithm to search HSC multi-color catalog for main sequence stars in the underlying low luminosity stellar system or stream HSC is the ONLY way to do this !!! 28