Stellar Duets: How Companions Shape the Life and Evolution of Stars Orsola De Marco

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


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?


Part 1Part 1What happens when stars interact?What happens when stars interact?


Evolution of 1-8 Mo single stars:

from the main sequence to white dwarf

Iben 1985

sdOB stars =


RGB: R ~100 Ro

AGB: R ~ 500 Ro

A twice-in-a-lifetime opportunity

R

R


Common envelope Roche Lobe overflow


= EBin

/ Eg

The common envelope efficiency parameter


Short-period binary Merged star

< 1 ~ 1


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 ...)


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.:


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


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


Bench: 0.1Mo + TP1

Sync: 0.1Mo + TP1

0.2Mo: 0.2Mo + TP1

TP10: 0.1Mo + TP10


Bench vs TP10: different AGB star

Bench

TP10

Orbital Perpendicular

68% of envelope lost in ~10 yr. Final configuration highly bipolar


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


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


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


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)


Part 2: Part 2: Planetary Nebula central star binarityPlanetary Nebula central star binarity


Evolution of 1-8 Mo stars from main sequence to white dwarf

Iben 1985


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


PN Halos

NGC6543 HST/NOT [OIII]/[NII]/Ha. (P. Harrington, R. Corradi)

2.5 pc


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?


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?


%

Period

10Bond 2000P < 3 days

Ciardullo et al. 19992000< P < 30,000 yr

So: How many PN have binary central stars?

Intermediate periods

?


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


The data look like this

And they are analyzed like this...


... after the analysis it looks like this


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


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”


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”


“There are alternatives to fighting…”

Sahai et al. 2000

He 2-113HST/PC1

H


He 2-113HST/HRC

F606

HST: Reflected light at 0.6 m


He 2-113HST/HRC

F814

HST: Reflected light at 0.8 m


VLT: dust emission at 3.5m

He 2-113VLT/NACO

L band


He 2-113VLT/NACO

M band



He 2-113VLT/MIDI

ACQ @ 8.7 m


VLT InterferometerMIDI

resolution 7masDouble-dust project

with Olivier Chesneau


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.


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


• 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


• 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


Thank you!


Thank you!


Thank you!



He2-138 HST/Ha (R. Sahai)

Inner parts of the PN


# 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


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

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