1. M. Shara Sept. 26, 2007 Planets, White Dwarfs, Cataclysmic Variables and SNIa in Star Clusters: Changing the Rules Mike Shara American Museum of Natural History

2. M. Shara Sept. 26, 2007Collaborators J. Hurley H. Richer D. Zurek R. Mardling

3. M. Shara Sept. 26, 2007 Goal: Completely self-consistent Star Cluster Evolution: N-body dynamics + Single + Binary Star Evolution--> to predict stellar populations/ test against HST data

4. M. Shara Sept. 26, 2007Overview How we do it: hardware and software The evolution of a cluster and it’s Blue Stragglers (M67) WDs in clusters…single, divorced, promiscuous SNIa (double degenerates) in clusters…enhanced rates CVs in Star Clusters - simulations - the tail wags the dog Planets in Star Clusters - Making warm Jupiters, eccentric Earths

5. M. Shara Sept. 26, 2007 Excellent dynamics laboratories AND Stellar evolution laboratories Direct integration = O(N 3 ) cost OPEN & GLOBULAR CLUSTERS Fokker-Planck and Monte Carlo: Dynamics/Evolution of 10 6 – 10 7 SINGLE stars BUT! Binaries (even 5%) control real clusters N-body essential to study cluster populations, planets

6. M. Shara Sept. 26, 2007 “GRAPE-6”: Hardwired for gravity simulations: GMm/r 2 10 18 to 10 19 operations/simulation TeraFlop Computers 1000 Pentiums in a pizza-sized box

7. M. Shara Sept. 26, 2007 NBODY4 software (Aarseth 1999, PASP, 111, 1333) includes stellar evolution and a binary evolution algorithm and as much realism as possible  fitted formulae as opposed to “live” or tables  rapid updating of M, R etc. for all stellar types and metallicities  done in step with dynamics  tidal evolution, magnetic braking, gravitational radiation, wind accretion, mass-transfer, common-envelope, mergers  perturbed orbits (hardening & break-up), chaotic orbits, exchanges, triple & higher-order subsystems, collisions, etc. … regularization techniques + Hermite integration with GRAPE + block time-step algorithm + external tidal field …

8. M. Shara Sept. 26, 2007 more on the binary evolution method … Detached Evolution - in timestep  t  update stellar masses  changes to stellar spins  orbital angular momentum and eccentricity changes  evolve stars  check for RLOF  set new timestep  repeat => semi-detached evolution

9. M. Shara Sept. 26, 2007 more on the binary evolution method … Semi-Detached Evolution Dynamical: Steady:  merger or CE (-> merger or binary)  calculate mass-transfer in one orbit  determine fraction accreted by companion  set timestep  account for stellar winds  adjust spins and orbital angular momentum  evolve stars  check if donor star still fills Roche-lobe  check for contact  repeat

10. M. Shara Sept. 26, 2007 Initial Conditions star formation stage is complete all residual gas has been removed all stars are coeval and same composition distribute masses (IMF) + brown dwarfs? +planets ? distribute stellar positions & velocities (density + virial) choose binary fraction and binary masses/separations lntegration dynamics (GRAPE... mostly) stellar & binary evolution (host) formation & dissolution of resonances collisions  mergers or destruction mass removal, e.g. tidal field Star Cluster Simulation Procedure Assumptions

11. M. Shara Sept. 26, 2007 Shortcomings of Current Models Initial conditions Neutron star retention Collision and merger products Uncertainty of binary evolution parameters * IMF? *binaries’ mass ratio and separation distributions? * interface with hydro code * Real time stellar and binary and merger-product evolution (Pfahl et al. 2002) *kick velocity at birth?

12. M. Shara Sept. 26, 2007 Simulation of a Rich Open Cluster Initial Conditions  12,000 single stars (0.1 - 50 M  )  12,000 binaries (a: flat-log, e: thermal, q: uniform)  solar metallicity (Z = 0.02)  Plummer sphere in virial equilibrium  circular orbit at R gc = 8 kpc  M ~ 18700 M   tidal radius 32 pc  T rh ~ 400 Myr   ~ 3 km/s  n c ~ 200 stars/pc 3  6-7 Gyr lifetime  4-5 weeks of GRAPE-6 CPU

13. M. Shara Sept. 26, 2007 M67 at 4 Gyr?  solar metallicity  50% binaries  luminous mass 1000 M  in 10pc  tidal radius 15pc  core radius 0.6pc, half-mass radius 2.5pc

14. M. Shara Sept. 26, 2007 M67 Observed CMD N-body Model CMD  N BS /N ms,2to = 0.15  R h,BS = 1.6pc  half in binaries  N BS /N ms,2to = 0.18  R h,BS = 1.1pc  half in binaries

15. M. Shara Sept. 26, 2007 More than 50% of Blue Stragglers result from dynamical intervention all observed orbital combinations  perturbations/hardening  exchanges  triples PERIOD e

16. M. Shara Sept. 26, 2007 20K STAR SIMULATIONS 16,000 single stars 16,000 single stars 2000 stars with Jupiters 2000 stars with Jupiters 2000 binaries 2000 binaries Kroupa, Tout, Gilmore IMF Kroupa, Tout, Gilmore IMF Z=0.004, 0.02 Z=0.004, 0.02 q = 0.1  1.0 q = 0.1  1.0 a from log normal distn, peak at 30 au a from log normal distn, peak at 30 au Eccentricity from a thermal distn. Eccentricity from a thermal distn. Planet separations 0.5  50 au Planet separations 0.5  50 au Galactic tidal field, no shocking Galactic tidal field, no shocking  speed ~ 2 km/s, n c ~ 500 stars/pc 3  speed ~ 2 km/s, n c ~ 500 stars/pc 3 open cluster: 5 Gyr of evolution open cluster: 5 Gyr of evolution

17. M. Shara Sept. 26, 2007 Dynamical Modification of Cluster Populations aka “Stellar Promiscuity” 500 cases of stellar infidelity 730 different stars involved (~15% of cluster) some stars swapped partner once (494) some did it twice (105) three times (48) four (27) five (14) and even 22 times (1) !! Usually the least massive star was ejected

18. M. Shara Sept. 26, 2007 NEVER A DULL MOMENT Over the entire run (t = 0.0  4566.1 Myr): 41 BLUE STRAGGLERS FORMED 5 CATACLYSMIC VARIABLES 48 DOUBLE WD SYSTEMS FORMED… 32/48 ARE NOT PRIMORDIAL BINARIES 8 DD collapses  Likely SN Ia

19. M. Shara Sept. 26, 2007 SNIa Motivation *SNIa – crucial to cosmology (acceleration) *Corrections to Mv now handled empirically because handled empirically because PROGENITORS ARE UNCERTAIN PROGENITORS ARE UNCERTAIN 1) SuperSoftSources (WD +RG) 2) Double Degenerates (WD +WD) PREDICTION: SNIa ENHANCED IN STAR CLUSTERS

20. M. Shara Sept. 26, 2007 N-body Evolution Example Primordial Binary M 1 = 6.88 M sun M 2 = 3.10 M sun a = 4050 R sun After 60 Myr: M 1 = 6.26 on AGB e = 0.0 (tides) RLOF => CE M 1 = 1.3 ONeWD After 434 Myr: M 2 = 2.02 on AGB M 1 = 1.3 (symbiotic) RLOF => CE M 2 = 0.8 COWD a = 2500 R sun DWD with t grav ~ 10 22 yr 1.3 ONeWD + 0.8 COWD a = 2500 Rsun

21. M. Shara Sept. 26, 2007 1.3 WD 0.8 WD DWD 9100 d 2.0 MS 630 Myr Resonant Exchange (few Myr) 14000 d e = 0.63 0.8 WD perturbed: 6000 d, e = 0.94 CE + CE => DWD (0.35 d) M=1.6 GR -> merger after 10 Gyr M tot = 1.6 M sun and then... SIRIUS-LIKE BINARY! SIRIUS-LIKE BINARY! 2.0MS 1.3 WD

22. M. Shara Sept. 26, 2007 Are Star Clusters (the) Type Ia Supernova Factories? 8DD =10x expected number of coalescing field double WDs in a modest open cluster Expect >n (globular)/n(open) ~ 10 3 x enhancement in globulars dJ/dt mM(m+M) f(e) J a 4 GENERAL RELATIVITY = -K dP/dt = -k P -5/3 Pcrit ~ 10 hours for ~(1+1) Msun for gravity waves

23. M. Shara Sept. 26, 2007 DDs which Merge in 1.4 Msun ID #S Types Masses Period/d ID #S Types Masses Period/d 79 80 CO CO 0.826 0.662 8.7096E-03 79 80 CO CO 0.826 0.662 8.7096E-03 33 34 CO CO 0.989 0.664 1.0715E-01 33 34 CO CO 0.989 0.664 1.0715E-01 75 76 CO CO 0.920 0.642 4.3652E-02 75 76 CO CO 0.920 0.642 4.3652E-02 86 8058 CO ONe 0.716 1.241 3.3884E-01 86 8058 CO ONe 0.716 1.241 3.3884E-01 63 64 CO CO 0.972 0.665 1.1482E-01 63 64 CO CO 0.972 0.665 1.1482E-01 57 58 ONe CO 1.057 0.574 1.0715E-01 57 58 ONe CO 1.057 0.574 1.0715E-01 61 62 CO CO 1.089 0.536 2.4547E-01 61 62 CO CO 1.089 0.536 2.4547E-01 95 96 CO CO 0.832 0.668 1.1220E-01 95 96 CO CO 0.832 0.668 1.1220E-01 NB! 7 of 8 SYSTEMS ARE PRIMORDIAL; WOULD NOT HAVE MERGED IN THE FIELD

24. M. Shara Sept. 26, 2007 Strongly Centrally Concentrated “Loaded Guns” MS DD

25. M. Shara Sept. 26, 2007 SINGLE WD DIVORCED WD BINARY WD OUTER BINARY WD

26. M. Shara Sept. 26, 2007 M>M Chandra HOW TO FIND “LOADED GUNS”

27. M. Shara Sept. 26, 2007 The White Dwarf Cooling Age and Dynamical History of the Metal-Poor Globular Cluster NGC6397  126 orbits with ACS in Cycle 13 (Mar/Apr 05) NGC 6397  [Fe/H] = -1.9  core-collapsed M4  [Fe/H] = -1.3  pre-core-collapse complements previous observations of M4  123 orbits with WFPC2 (Apr 01) (Hansen et al. 2002, 2004)

28. M. Shara Sept. 26, 2007 11.9  0.4 Gyr 12.1  0.7 Gyr

29. M. Shara Sept. 26, 2007 Contamination of the WD luminosity function (and CMD distribution) 30K, 50% binaries  4 Gyr (Hurley & Shara 2003)

30. M. Shara Sept. 26, 2007

32. inside R h outside R h

33. M. Shara Sept. 26, 2007 (small) Globular Cluster Model  100,000 stars, 5% binaries, Z = 0.001, tidal field  20,000 stars at core-collapse (15-16 Gyr) RcRc RhRh

34. M. Shara Sept. 26, 2007

36. binary frequency < 5% minimal contamination

37. M. Shara Sept. 26, 2007 Cataclysmic Variable =CV= Classical Nova or Dwarf Nova= White Dwarf Accreting From a Red Dwarf Companion Accretion energy via Accretion disk instability  L 100x “dwarf nova” L  10 5-6 Lsun

38. M. Shara Sept. 26, 2007 A White Dwarf Forms INSIDE a Red Giant Sometimes a companion star is engulfed 1,000,000 X denser than the Sun

39. M. Shara Sept. 26, 2007 The long-sought Globular cluster CVs?! (47 Tuc - Grindlay et al)

40. M. Shara Sept. 26, 2007 HST/FUV NGC 2808 Dieball, Knigge, Zurek, Shara, long 2005

41. M. Shara Sept. 26, 2007 Non-standard CV formation and evolution + 0.37 M  MS 0.74 M  MS 0.71 M  MS 0.91 M  WD WD: 0.91 M  MSS: 0.74 M  P=4302d, e=0.97  in cluster core  perturbations -> chaos  P=0.52d, circular  RLOF No Common-Envelope! accelerated CV evolution of individual systems

42. M. Shara Sept. 26, 2007 CV orbital periods Field Cluster

43. M. Shara Sept. 26, 2007 Planet Motivation 0 hot Jupiters orbiting 34,000 MSS in 47 Tuc….expect ~20 (Gilliland et al) Davies & Sigurdsson, Bonnell et al, Smith & Bonnell  Most close planets (<0.3 au) survive …WHERE ARE THEY?

44. M. Shara Sept. 26, 2007 N=20,000 STAR SIMULATIONS 18,000 single stars 18,000 single stars Kroupa, Tout, Gilmore IMF Kroupa, Tout, Gilmore IMF Z= 0.017 Z= 0.017 100 single stars with Earth +Jupiter OR 100 single stars with Earth +Jupiter OR Neptune + Jupiter Neptune + Jupiter Initial a, e of planets = Solar System values Initial a, e of planets = Solar System values 2000 binaries with q (mass ratio) = 0.1  1.0 2000 binaries with q (mass ratio) = 0.1  1.0 a from log normal distn, peak at 30 au a from log normal distn, peak at 30 au Stellar Binaries’ eccentricity: a thermal distn. Stellar Binaries’ eccentricity: a thermal distn. Galactic tidal field, no shocking Galactic tidal field, no shocking  speed ~ 2 km/s, n c ~ 500 stars/pc 3  speed ~ 2 km/s, n c ~ 500 stars/pc 3 Massive open cluster: 5 Gyr of evolution Massive open cluster: 5 Gyr of evolution

45. M. Shara Sept. 26, 2007 N=2,000 STAR SIMULATIONS 1400 single stars 1400 single stars 600 Binaries 600 Binaries 100 single stars with Earth +Jupiter OR 100 single stars with Earth +Jupiter OR Neptune + Jupiter Neptune + Jupiter Initial a, e of planets = Solar System values Initial a, e of planets = Solar System values  speed ~ 2 km/s, n c ~ 10,000 stars/pc 3  speed ~ 2 km/s, n c ~ 10,000 stars/pc 3 Sparse open cluster: 5 Gyr of evolution Sparse open cluster: 5 Gyr of evolution

46. M. Shara Sept. 26, 2007 N= 20,000 stars

47. M. Shara Sept. 26, 2007 N=20,000 stars

48. M. Shara Sept. 26, 2007 N = 2000 stars

49. M. Shara Sept. 26, 2007 N= 20,000 Stars

50. M. Shara Sept. 26, 2007 4 Encounters “ionize” Jupiter AND LEAVE BEHIND AN ECCENTRIC EARTH e =0.6 Which escapes the cluster with its host star

51. M. Shara Sept. 26, 2007 Early Wanderlust by Neptune

52. M. Shara Sept. 26, 2007 Ionization of Neptune 4.5 Gyr later

53. M. Shara Sept. 26, 2007 An eccentric Jupiter-Neptune System - released into the field at 460 Myr- (from N=2000) “fossil eccentricity” Imprinted by previous cluster environment

54. M. Shara Sept. 26, 2007 JUPITERS Log a N 2 4 0 400 Myr 64 Jupiters

55. M. Shara Sept. 26, 2007 SATURN JUPITER EARTH EARTH e a T Myr

56. M. Shara Sept. 26, 2007

57. Conclusions – Planets in Star Clusters The Solar System can escape quite intact from an N=2000 star cluster (Adams+Laughlin 2001) The Solar System can escape quite intact from an N=2000 star cluster (Adams+Laughlin 2001) MANY Tramp planets MUST EXIST! MANY Tramp planets MUST EXIST! More “damage” as N and density increases More “damage” as N and density increases Very large eccentricity changes are common during stellar encounters Very large eccentricity changes are common during stellar encounters Eccentric singles and doubles are released from clusters into the field (cf Malmberg,Davies et al) Eccentric singles and doubles are released from clusters into the field (cf Malmberg,Davies et al) “Tepid” Jupiters are easy to form…a = 3 - 7 AU “Tepid” Jupiters are easy to form…a = 3 - 7 AU No “hot” Jupiters seen yet No “hot” Jupiters seen yet Coming: Jupiter + Saturn; 3-4 planets Coming: Jupiter + Saturn; 3-4 planets

58. M. Shara Sept. 26, 2007 CONCLUSIONS – SNIa and DD *Beware of DD in age-dating the Universe *HARDENING OF DDs MANUFACTURES “LOADED GUNS” IN CLUSTERS…. “LOADED GUNS” IN CLUSTERS…. Grav. Radiation does the rest Grav. Radiation does the rest *Long hardening timescale  No z peak in SNIa (J. Tonry) *Look in clusters (eg M67, NGC 188) for very short period DDs (~5 today) very short period DDs (~5 today)

59. M. Shara Sept. 26, 2007

60. SINGLE JUPITERS (0.05-50 AU) IN AN OPEN CLUSTER LIBERATED FROM PARENT ESCAPING FROM CLUSTER

61. M. Shara Sept. 26, 2007 EARTHS Log a N 400 Myr 22 Earths

62. M. Shara Sept. 26, 2007 eccentricity N Earths 400 Myr 22 Earths

63. M. Shara Sept. 26, 2007

64. PLANET LIBERATION LOCATIONS

65. M. Shara Sept. 26, 2007 PLANET LIBERATION VELOCITIES