Transcript Origin of close binary systems

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
- 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
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!
Young, massive Orion
Trapezium multiples:
High-resolution
infrared speckle
reconstruction
B4
B1
B2
orbital motion, stellar masses, & ages
B3
0.5’’
B2-3:
sep = 117 mas
A2
A1
sep =
215 mas
0.1’’
HST image
10 AU
C1
**
1’’
C2
0.05’’
1997.8
1998.8
2003.8
2001.2
Schertl et al. (2003, A&A)
sep = 38 mas
1999.1
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)
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)
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
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.
García, B. & Mermilliod, J. C. 2001, A&A 368, 122
Brown, A. G. A. 2001, AN 322, 43
A Trapezium system in M16?
McCaughrean, M. J. &
Andersen, M. 2002,
A&A 389, 513
Young, massive Orion
Trapezium multiples:
High-resolution
infrared speckle
reconstruction
B4
B1
B2
orbital motion, stellar masses, & ages
B3
0.5’’
B2-3:
sep = 117 mas
A2
A1
sep =
215 mas
0.1’’
HST image
10 AU
C1
**
1’’
C2
0.05’’
1997.8
1998.8
2003.8
2001.2
Schertl et al. (2003, A&A)
sep = 38 mas
1999.1
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
Definition ``Multiplicity´´
or companion star fraction (csf)
csf
B  2T  3Q

S  B T Q
Reipurth & Zinnecker 1993, A&A 278, 81
e.g.
csf = 1.5
for Trapezium stars
*
.
*..
*.:
*
PS.
csf = 0.5
1 single
1double
1 triple
1 quadruple
for low-mass stars (T Tauri stars)
in Orion Nebula Cluster
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
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?)
Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T.
2001, A&A 365, 49
Origin of close binary systems
(Bonnell & Bate 2005)
Idea:
wide low-mass binary
mass + A.M. accretion
close high-mass binary
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)
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?
Theta-1-A
Theta-1-B
Theta-1_C
16 + 2 Msun, sep = 1 AU
7 + 3 Msun, sep = 0.13AU
40 + 5 Msun, sep = 16 AU
Theta-2-A
Nu Ori
25 + 8 Msun, sep = 0.5 AU
14 + 3 Msun, sep = 0.35AU
Iota Ori
21 + 17 Msun, sep =? Ecc.!
Other observational results
for other young star clusters:
S255-IR, NGC3603, R136, ...
Zinnecker, Correia, Stecklum et al. 2005, in prep.
Stolte, A.; Brandner, W.; Brandl, B.; Zinnecker, H.;
Grebel, E. K. 2004, AJ 128, 765
Stolte, A.; Brandner, W.; Brandl, B.; Zinnecker, H.;
Grebel, E. K. 2004, AJ 128, 765
Moffat, A. F. J.; Drissen, L.; Shara, M. M. 1994, ApJ 436, 183
Hofmann, K.-H. & Weigelt, G. 1986, A&A 167, L15
Weigelt, G.; Baier, G. 1985,
A&A 150, L18
Massey, Ph.; Hunter, D. A. 1998,
ApJ 493, 180
Massey, Ph.; Penny, L. R.; Vukovich, J. 2002, ApJ 565, 982
Apai, D.; Bik, A.; Kaper, L.; Henning, Th.; Zinnecker, H. in prep.
Bosch, G.; Selman, F.; Melnick, J.; Terlevich, R. 2001, A&A 380, 137
Conclusions
--------------1) 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!
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
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
consequences
b) questions related to multiplicity
very massive stars (M > 100 Mo)
through binary mergers?
multiplicity of isolated
massive stars in the field?
multiplicity and stellar rotation
of the components?
multiplicity in low-metallicity
environments (LMC / SMC)?
multiplicity among massive stars
conclusions:
M > 8 M
SpT earlier B2
1) Trapezia within Orion Trapezium
2) preponderance of tight binaries
SB1: q  1
lower masses
SB2: q = 1
higher masses
3) 20 out of 25 O-stars are triple,
consisting of SB + VB pairs (Mason)
4) multiplicity among massive stars
higher than among low-mass (3x)
WHY?  gravitational dynamics