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STScI Workshop on Massive Stars 8 - 11 May 2006 Baltimore

STScI Workshop on Massive Stars 8 - 11 May 2006 Baltimore. Multiplicity of Massive Stars - Clues and Consequences Hans Zinnecker (AIP, Potsdam, Germany). goal of this short contribution - remind you of high incidence of binaries, triples, and Trapezium systems

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STScI Workshop on Massive Stars 8 - 11 May 2006 Baltimore

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  1. STScI Workshop on Massive Stars 8 - 11 May 2006 Baltimore Multiplicity of Massive Stars - Clues and Consequences Hans Zinnecker (AIP, Potsdam, Germany)

  2. goal of this short contribution - remind you of high incidence of binaries, triples, and Trapezium systems - remind you of preponderance of close massive binaries (SB2, SB1, eclipsing binaries) - new idea to explain the origin of Trapezium systems - new idea to explain the origin of the close binaries

  3. goal of this short contribution (ctd.) - Example: The Orion Trapezium Cluster (origin and future evolution) - Question: seperations and mass ratios for massive close binaries to become ``interactive´´? (case A, B, C mass transfer) RLOF: mass / A.M. accretion efficiency? LBV: violent mass loss (stellar wind), onset at which initial stellar mass? stellar rejuvenation? population synthesis!

  4. C1 * C2 * 0.05’’ Young, massive Orion Trapeziummultiples: orbital motion, stellar masses, & ages High-resolution infrared speckle reconstruction B4 B1 B2 B2-3: sep = 117 mas B3 0.5’’ A2 sep = 215 mas A1 0.1’’ HST image 10 AU 1997.8 1998.8 2003.8 1’’ 1999.1 2001.2 Schertl et al. (2003, A&A) sep = 38 mas

  5. other relevant considerations (not today) - formation clues from observed multiplicity trends in different stellar environments - consequences of multiplicities for runaways, non-local supernovae, starburst population synthesis including exotic products of binary stellar evolution (high mass X-ray binaries, binary pulsars, TZ-objects)

  6. outline of this talk - quick summary of multiplicity observations for massive stars (spectroscopic, speckle, adaptive optics, HST/FGS observations) - example: the multiplicities of the Orion Trapezium stars and the companion star frequency of high-mass vs. low-mass stars - SPH simulations: hierarchical star cluster formation and the merging of subclusters as a model for the origin of Trapezia - origin due to formation or early dynamical N-body evolution (accretion onto low-mass binary, hardening of a wide-binary)

  7. outline of another talk (not today) - massive binaries in different stellar environments: young clusters rich and poor, OB associations, runaway stars - stellar evolution of massive tight binaries (RLOF; mergers) high-mass X-ray binaries, supernova kicks, gamma-ray bursts

  8. Some References - Bonnell and Bate (2005): MNRAS 362, 915 - Langer et al. (2003), IAU-Symp. 212 - Mason et al. (1998), AJ 115, 821 - Mermilliod/Garcia (2001), IAU-Symp. 200 - Petrovic et al. (2005), A&A 435, 1013 - Portegies Zwart (2001), IAU-Symp. 200 - Preibisch et al (2001), IAU-Symp. 200 - Van Bever & Vanbeveren (1998), A&A 334, 21 - Zinnecker (2003), IAU-Symp. 212 - Zinnecker (2006): Sacacomie Proc. - Zinnecker (2006): Tartu Proc. - Zinnecker (2006): ESO Workshop Proc.

  9. García, B. & Mermilliod, J. C. 2001, A&A 368, 122

  10. Brown, A. G. A. 2001, AN 322, 43

  11. A Trapezium system in M16? McCaughrean, M. J. & Andersen, M. 2002, A&A 389, 513

  12. C1 * C2 * 0.05’’ Young, massive Orion Trapeziummultiples: orbital motion, stellar masses, & ages High-resolution infrared speckle reconstruction B4 B1 B2 B2-3: sep = 117 mas B3 0.5’’ A2 sep = 215 mas A1 0.1’’ HST image 10 AU 1997.8 1998.8 2003.8 1’’ 1999.1 2001.2 Schertl et al. (2003, A&A) sep = 38 mas

  13. Definition ``massive´´ (primary) stellar mass M* > 10 solar masses spectral type earlier than B2 main sequence lifetime < 10 Myr Definition ``multiplicity´´ binaries (EB, SB, VB) hierarchical triples / quadruples Trapezium-type systems

  14. Definition ``Multiplicity´´ or companion star fraction (csf) Reipurth & Zinnecker 1993, A&A 278, 81 e.g. csf = 1.5 for Trapezium stars * 1 single * . 1double * . . 1 triple * . : 1 quadruple PS. csf = 0.5 for low-mass stars (T Tauri stars) in Orion Nebula Cluster

  15. Origin of the Trapezium Cluster via hierarchical merging of subclusters SPH simulations of a 1000 Msun turbulent mol. cloud Bonnell, I. A.; Bate, M. R.; & Vine, St. G. 2003, MNRAS 343, 413

  16. dynamical and binary stellar evolution of the Trapezium Cluster (next 30 Myr) dynamical ejections of massive stars (cf. AE Aurigae and  Columbae) close binary evolution of massive stars (future of Theta-1 Ori C, A, B binaries?)

  17. Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T. 2001, A&A 365, 49

  18. Origin of close binary systems (Bonnell & Bate 2005) Idea: wide low-mass binary mass + A.M. accretion close high-mass binary

  19. Origin of close binary systems Another (older) idea: shrinking (hardening) of wide high-mass binary systems by close stellar encounters in dense clusters (energy exchange in multiple systems)

  20. Future stellar evolution of the close binaries in the Orion Trapezium Cluster Case A mass transfer: P ~ 10 d Case B mass transfer: P ~ 100 d Case C mass transfer: P ~ 1000 d WR/O-stars, RSG, SN II, HMXB?

  21. Theta-1-A 16 + 2 Msun, sep = 1 AU Theta-1-B 7 + 3 Msun, sep = 0.13AU Theta-1_C 40 + 5 Msun, sep = 16 AU Theta-2-A 25 + 8 Msun, sep = 0.5 AU Nu Ori 14 + 3 Msun, sep = 0.35AU Iota Ori 21 + 17 Msun, sep =? Ecc.!

  22. Other observational results for other young star clusters: S255-IR, NGC3603, R136, ...

  23. Zinnecker, Correia, Stecklum et al. 2005, in prep.

  24. Stolte, A.; Brandner, W.; Brandl, B.; Zinnecker, H.; Grebel, E. K. 2004, AJ 128, 765

  25. Stolte, A.; Brandner, W.; Brandl, B.; Zinnecker, H.; Grebel, E. K. 2004, AJ 128, 765

  26. Moffat, A. F. J.; Drissen, L.; Shara, M. M. 1994, ApJ 436, 183

  27. Hofmann, K.-H. & Weigelt, G. 1986, A&A 167, L15

  28. Weigelt, G.; Baier, G. 1985, Massey, Ph.; Hunter, D. A. 1998, A&A 150, L18 ApJ 493, 180

  29. Massey, Ph.; Penny, L. R.; Vukovich, J. 2002, ApJ 565, 982

  30. Apai, D.; Bik, A.; Kaper, L.; Henning, Th.; Zinnecker, H. in prep.

  31. Bosch, G.; Selman, F.; Melnick, J.; Terlevich, R. 2001, A&A 380, 137

  32. Conclusions • --------------- • Some of the most exciting cosmic phenemena • due to the presence of massive close binaries • 2) Studies of star forming regions & young clusters • allow us to observe binary parameter distributions • give extra info on massive star formation • provide I.C. for models of interacting binary evol • 3) We all need to learn more about binary evolution! • 4) Orion and other nearby clusters as starting point

  33. Conclusions (ctd.) 4) Dynamical interactions also important (ejections, runaway stars) and generally underestimated… 5) Orion Trapezium cluster and other nearby young clusters as a starting point (link I.C. to evolutionary consequences) PS. Watch out for ARAA review on massive star formation in preparation by YORKE & ZINNECKER 2007

  34. consequences a) implications of high-mass multiplicity derive stellar masses (eclipsing SB2) correct upper IMF slope (steepening) correct cluster vel. dispersion (dyn. mass) origin of runaway OB stars (ejection) high-mass X-ray binaries (stellar mass BH) colliding winds, orbital drag & decay effect on WR & SN-II progenitor masses distance determination using eclipsing SB2

  35. consequences b) questions related to multiplicity very massive stars (M > 100 Mo)through binary mergers? multiplicity of isolatedmassive stars in the field? multiplicity and stellar rotationof the components? multiplicity in low-metallicityenvironments (LMC / SMC)?

  36. multiplicity among massive stars M > 8 M SpT earlier B2 • conclusions: • Trapezia within Orion Trapezium • preponderance of tight binaries • SB1: q  1 lower masses • SB2: q = 1 higher masses • 20 out of 25 O-stars are triple, • consisting of SB + VB pairs (Mason) • multiplicity among massive stars • higher than among low-mass (3x) • WHY?gravitational dynamics

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