Slide 1 Stellar Duets February 18th, 2005
Stellar Duets: Stellar Duets: How Companions Shape the Life and How Companions Shape the Life and
Evolution of StarsEvolution of Stars
Orsola De MarcoOrsola De Marco
American Museum of Natural HistoryAmerican Museum of Natural History
February 18February 18thth, 2005, 2005
Merging binaries. Simulations UKAFF
Slide 2 Stellar Duets February 18th, 2005
Part 2: An experimental test:Part 2: An experimental test:PN Central Star binarityPN Central Star binarity
Part 1: The theoretical “shopping list”: Part 1: The theoretical “shopping list”: What we would like to know about binary interactionsWhat we would like to know about binary interactions
The Question that drives us:The Question that drives us:How does binarity change stellar evolution?How does binarity change stellar evolution?
Slide 3 Stellar Duets February 18th, 2005
Part 1Part 1What happens when stars interact?What happens when stars interact?
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Evolution of 1-8 Mo single stars:
from the main sequence to white dwarf
Iben 1985
sdOB stars =
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RGB: R ~100 Ro
AGB: R ~ 500 Ro
A twice-in-a-lifetime opportunity
R
R
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Common envelope Roche Lobe overflow
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= EBin
/ Eg
The common envelope efficiency parameter
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Short-period binary Merged star
< 1 ~ 1
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Past work in common envelope theory:Ostriker 1975, Paczynski 1976 (proposal)eg, Rasio & Livio 1996 (analytical)eg, Taam & Sandquist 2000 (numerical)
Past work in common envelope observations:e.g. Hillwig et al. 2002, Drake & Sarna 2003Sarna et al. 1995, Bleach et al. 2000
The common envelope phase is inferred by the presence of evolved short-period binaries (CV, Type Ia SN, LMXB ...)
Slide 10 Stellar Duets February 18th, 2005
Shopping list item 1: what can we find out with current codes
Common envelope efficiency fa
47 Tuc DSS/Chandra (G. Pooley)
useful in: (i) populations synthesis codes: prediction binary populations characteristics (ii) N-body codes: binaries in clusters, e.g.:
Slide 11 Stellar Duets February 18th, 2005
Companion's orbit
AGB star
6 AU
Code: Burkert & Bodenheimer 1993Method: Sandquist et al. 1998
Initial common envelope simulations(De Marco et al. 2003)
E. Sandquist
M.-M. Mac Low
F. Herwig
R. Taam
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AGB star Companion
Model Envelope Core Envelope EnvelopeName Rotation Mass Mass Radius Mass
? (Mo) (Mo) (AU) (Mo)
Bench No 0.56 0.69 1.85 0.1
Sync Yes 0.56 0.69 1.85 0.1
0.2Mo No 0.56 0.69 1.85 0.2
TP10 No 0.60 0.44 3.00 0.1
4 common envelope tests
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Bench: 0.1Mo + TP1
Sync: 0.1Mo + TP1
0.2Mo: 0.2Mo + TP1
TP10: 0.1Mo + TP10
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Bench vs TP10: different AGB star
Bench
TP10
Orbital Perpendicular
68% of envelope lost in ~10 yr. Final configuration highly bipolar
Slide 15 Stellar Duets February 18th, 2005
Model Mass lost Final Timescale FateName Separation
( =%)Mo ( / )AU Ro ( )yr
Bench 0.03=4% 0.09/4 9 0.03 ?Collides
Sync 0.7=5% 0.06/0 8 0.3 ?Stops
0.Mo 0.38=55% 0.0/5 8 0.4 Stops
0TP 0.30=68% 0.49/78 .00 Stops
Results of common envelope simulations
Slide 16 Stellar Duets February 18th, 2005
is testable (Yungelson et al. 1993)
sdOB stars: 70% binaries. Period distribution peaks around 1 day
Maxted et al. 2001 Morales-Rueda et al. 2003
Slide 17 Stellar Duets February 18th, 2005
Rey et al. 2001
sdOB stars = binaries sdOB stars = blue HB stars
blue HB stars = binaries
Stellar binarity: the solution of the the “second parameter” problem in
globular clusters
Observations in hand. with D. Zurek, J. Ouellette, J. Hurley, T. Lanz and M. Shara
An observational parenthesis
Slide 18 Stellar Duets February 18th, 2005
1) What happens in the deep interior of the primary? useful in: (i) can low mass companions eject the envelope? (formation of CVs with BD companions
[Politano 2004]) (ii) can a planet change into a more massive object (e.g., Siess & Livio 1999)?
2) What happens when stars merge. useful in: (i) Blue stragglers (Saffer et al. 2000)
(ii) R Coronae Borealis stars (Clayton 1996) (iii) Wolf-Rayet central stars (De Marco & Soker 2002) (iv) SN Type Ia (Langer et al. 2000)
(v) Other types of SN??? (suggestion by E.F. Brown)
Shopping list items 2 and 3: next code FLASH (Fryxell et al. 2000)
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Part 2: Part 2: Planetary Nebula central star binarityPlanetary Nebula central star binarity
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Evolution of 1-8 Mo stars from main sequence to white dwarf
Iben 1985
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Spherical(10%)
Bipolar(11%)
Elliptical(79%)
Observed PN morphologies
Abell 39WYIN 3.5 m telescope [OIII] (G. Jacoby)
Hubble 5HST [OII]/[NII]/[OIII](Balik, Ike, Mellema)
NGC6826 HST [NII]/[OIII]/V(Balick et al.)
5 ly
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PN Halos
NGC6543 HST/NOT [OIII]/[NII]/Ha. (P. Harrington, R. Corradi)
2.5 pc
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The PN formation scenarios to explain the morphology
• Interactive winds scenario (Kwok 1982; Balick 1987). Needs fast rotation and/or magnetic fields to create
axi-symmetric AGB mass-loss (e.g. Garcia-Segura et al. 2003).
• Hole punching scenario (Sahai & Trauger 1998). Needs fast outflows to punch holes into symmetric AGB
mass-loss (e.g., Garcia-Arredondo & Frank 2004).
What is the origin of the axi-symmetric AGB mass-loss and the outflows?
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Binary star can create rotation, magnetic fields, jets and gravitational focussing.
Binarity of central stars provides a potential explanation of PN morphology.
But where are the binary central stars?
Slide 25 Stellar Duets February 18th, 2005
%
Period
10Bond 2000P < 3 days
Ciardullo et al. 19992000< P < 30,000 yr
So: How many PN have binary central stars?
Intermediate periods
?
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2002 the hunt starts: radial velocity survey of central stars of PN
A. FlemingO. De Marco
H. Bond
D. Harmer
3.6 m WYIN
G. Jacoby
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The data look like this
And they are analyzed like this...
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... after the analysis it looks like this
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Central Star Name#
measurementsσ
(km/s)
Error (km/s)
Probability of RV
variability
1 PHL932 9 3.8 2.6 98%
2 BD+33 14 3.7 2.3 100%
3 IC4593 8 11.9 3.0 100%
4 NGC6210 6 5.8 2.4 100%
5 IRAS 19127+1717 12 9.5 3.1 100%
6 LSIV -12.111 15 12.1 2.3 100%
7 NGC6891 16 4.6 2.6 100%
8 M1-77 15 9.5 2.5 100%
9 A78 11 5.1 2.6 100%
10 M2-54 15 11.8 2.6 100%
11 Sa4-1 4 2.4 2.4 71%
Control BD+28 4211 14 2.9 3.3 24%
5.1 day
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90
Bond 2000P < 3 days
Ciardullo et al. 19992000 > P > 30,000 yr
Binary fraction: 10/11 ~ 90%
High proportion of binarity for periods < 100 d
%
Period
10Bond 2000P < 3 days
Ciardullo et al. 19992000< P < 30,000 yr
Periods must be determined, “it is the only way to be sure”
Slide 31 Stellar Duets February 18th, 2005
Binary fraction: ~ 90%Periods: “short”Periods peak somewhere 3 d < P < 100 d
3 d < P < 100 d
Ciardullo et al. 19992000 > P > 30,000 yr
%
Period
10Bond 2000P < 3 d
Ciardullo et al. 19992000 < P < 30,000 yr
Periods must be determined, “it is the only way to be sure”
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“There are alternatives to fighting…”
Sahai et al. 2000
He 2-113HST/PC1
H
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He 2-113HST/HRC
F606
HST: Reflected light at 0.6 m
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He 2-113HST/HRC
F814
HST: Reflected light at 0.8 m
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VLT: dust emission at 3.5m
He 2-113VLT/NACO
L band
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He 2-113VLT/NACO
M band
VLT: dust emission at 4.8m
Slide 37 Stellar Duets February 18th, 2005
He 2-113VLT/MIDI
ACQ @ 8.7 m
VLT: dust emission at 8.7m
VLT InterferometerMIDI
resolution 7masDouble-dust project
with Olivier Chesneau
Slide 38 Stellar Duets February 18th, 2005
Consequences of higher binarity
• New basis for the understanding of PN morphology.
• Another puzzle for stellar evolution?
• Constraint on Common Envelope efficiency • New constraint on population theory (e.g., prediction SN Type Ia) and N-body simulations.
Slide 39 Stellar Duets February 18th, 2005
Further impact of AGB binarity
• Prevention of 3rd-dredge-up:
• Different galactic carbon, oxygen and s-process element yields. Consequences for models of galactic chemical evolution (e.g. Dwek 1998).
• Presence of circumstellar disks:
• PAH formation: environment-dependent. PAH yields important for molecular cloud formation (Wolfire et al 1995).
• Organic molecules formation/evolution in AGB, proto-PN and PN (Kwok et al. 1999).
• SiC grains in proto-PN and in presolar grains (Speck & Hoffmeister 2004, Clayton 2003).
Red Rectangle HST H. van Winkel
2700 AU
Orion proplyd/ HST
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• CE simulations on a broad scale: sensitivity to initial conditions, calculation.
• Start new generation of calculations: small companions, mergers.
• CE calculations assist population syntheses that predict binary classes (CV, SN Type Ia) and N-body simulations.
Summary Part 1
Slide 41 Stellar Duets February 18th, 2005
• PN binarity: explanation of morphology, challenge in stellar evolution, PN period-distribution: test of (AGB).
• (sdOB period-distribution: test of (RGB), solution to second parameter problem in globular clusters??)
• AGB binarity: altered stellar yields of atoms, molecules and minerals.
Summary Part 2
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Thank you!
Slide 43 Stellar Duets February 18th, 2005
Thank you!
Slide 44 Stellar Duets February 18th, 2005
Thank you!
Slide 45 Stellar Duets February 18th, 2005
Slide 46 Stellar Duets February 18th, 2005
He2-138 HST/Ha (R. Sahai)
Inner parts of the PN
Slide 47 Stellar Duets February 18th, 2005
# of stars in the Galaxy: 1011 (Duquennoy & Mayor 1991: ~60% binaries)Primaries w/ lifetime shorter than age of the universe: 1010 yrPrimaries w/ companion < 500 Ro: (Duquennoy & Mayor: ~25%)Mean age of stars: 10 GyrPN visibility time: < 50,000 yr
# of PN with close binary central stars: < 12,500# of PN in the Galaxy: 10,000 +/- 4000 (Jacoby 1986)
Some binaries will merge, some will never ascend AGB.
Some population syntheses predict lower PN binary fraction (e.g., Yungelson et al. 1993).
Counting stars on the back of an envelope
Slide 48 Stellar Duets February 18th, 2005
TP10 simulation: density contour plot
68% of envelope lost in ~10 yr. Final configuration highly bipolar
Orb
ital p
lane
Per
p. p
lane
1000 days 2000 days 3000 days 4000 days