Slide 1Stellar Duets February 18 th, 2005 Stellar Duets: How Companions Shape the Life and Evolution of Stars Orsola De Marco American Museum of Natural History February 18 th, 2005 Merging binaries. Simulations UKAFF

Slide 2Stellar Duets February 18 th, 2005 Part 2: An experimental test: PN Central Star binarity Part 1: The theoretical “shopping list”: What we would like to know about binary interactions The Question that drives us: How does binarity change stellar evolution?

Slide 3Stellar Duets February 18 th, 2005 Part 1 What happens when stars interact?

Slide 4Stellar Duets February 18 th, 2005 Evolution of 1-8 M o single stars: from the main sequence to white dwarf Iben 1985 sdOB stars =

Slide 5Stellar Duets February 18 th, 2005 RGB: R ~100 R o AGB: R ~ 500 R o A twice-in-a-lifetime opportunity R R

Slide 6Stellar Duets February 18 th, 2005 Common envelopeRoche Lobe overflow

Slide 7Stellar Duets February 18 th, 2005   =  E Bin /  E g The common envelope efficiency parameter

Slide 8Stellar Duets February 18 th, 2005 Short-period binary Merged star  < 1  ~ 1

Slide 9Stellar Duets February 18 th, 2005 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 2003 Sarna et al. 1995, Bleach et al The common envelope phase is inferred by the presence of evolved short-period binaries (CV, Type Ia SN, LMXB...)

Slide 10Stellar Duets February 18 th, 2005 Shopping list item 1: what can we find out with current codes  Common envelope efficiency  f      a  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 11Stellar Duets February 18 th, 2005 Companion's orbit AGB star 6 AU Code: Burkert & Bodenheimer 1993 Method: Sandquist et al Initial common envelope simulations (De Marco et al. 2003) E. Sandquist M.-M. Mac Low F. Herwig R. Taam

Slide 12Stellar Duets February 18 th, common envelope tests

Slide 13Stellar Duets February 18 th, 2005 Bench: 0.1Mo + TP1 Sync: 0.1Mo + TP1 0.2Mo: 0.2Mo + TP1 TP10: 0.1Mo + TP10

Slide 14Stellar Duets February 18 th, 2005 Bench vs TP10: different AGB star Bench TP10 OrbitalPerpendicular 68% of envelope lost in ~10 yr. Final configuration highly bipolar

Slide 15Stellar Duets February 18 th, 2005 Results of common envelope simulations

Slide 16Stellar Duets February 18 th, 2005  is testable (Yungelson et al. 1993) sdOB stars: 70% binaries. Period distribution peaks around 1 day Maxted et al Morales-Rueda et al. 2003

Slide 17Stellar Duets February 18 th, 2005 Rey et al 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 18Stellar Duets February 18 th, ) 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)

Slide 19Stellar Duets February 18 th, 2005 Part 2: Planetary Nebula central star binarity

Slide 20Stellar Duets February 18 th, 2005 Evolution of 1-8 M o stars from main sequence to white dwarf Iben 1985

Slide 21Stellar Duets February 18 th, 2005 Spherical (10%) Bipolar (11%) Elliptical (79%) Observed PN morphologies Abell 39 WYIN 3.5 m telescope [OIII] (G. Jacoby) Hubble 5 HST [OII]/[NII]/[OIII] (Balik, Ike, Mellema) NGC6826 HST [NII]/[OIII]/V (Balick et al.) 5 ly

Slide 22Stellar Duets February 18 th, 2005 PN Halos NGC6543 HST/NOT [OIII]/[NII]/Ha. (P. Harrington, R. Corradi) 2.5 pc

Slide 23Stellar Duets February 18 th, 2005 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?

Slide 24Stellar Duets February 18 th, 2005 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 25Stellar Duets February 18 th, 2005 % Period 10 Bond 2000 P < 3 days Ciardullo et al < P < 30,000 yr So: How many PN have binary central stars? Intermediate periods ?

Slide 26Stellar Duets February 18 th, the hunt starts: radial velocity survey of central stars of PN A. Fleming O. De Marco H. Bond D. Harmer 3.6 m WYIN G. Jacoby

Slide 27Stellar Duets February 18 th, 2005 The data look like this And they are analyzed like this...

Slide 28Stellar Duets February 18 th, after the analysis it looks like this

Slide 29Stellar Duets February 18 th, day

Slide 30Stellar Duets February 18 th, Bond 2000 P < 3 days Ciardullo et al > P > 30,000 yr Binary fraction: 10/11 ~ 90% High proportion of binarity for periods < 100 d % Period 10 Bond 2000 P < 3 days Ciardullo et al < P < 30,000 yr Periods must be determined, “it is the only way to be sure”

Slide 31Stellar Duets February 18 th, 2005 Binary fraction: ~ 90% Periods: “short” Periods peak somewhere 3 d < P < 100 d 3 d < P < 100 d Ciardullo et al > P > 30,000 yr % Period 10 Bond 2000 P < 3 d Ciardullo et al < P < 30,000 yr Periods must be determined, “it is the only way to be sure”

Slide 32Stellar Duets February 18 th, 2005 “There are alternatives to fighting…” Sahai et al He HST/PC1 H 

Slide 33Stellar Duets February 18 th, 2005 He HST/HRC F606 HST: Reflected light at 0.6  m

Slide 34Stellar Duets February 18 th, 2005 He HST/HRC F814 HST: Reflected light at 0.8  m

Slide 35Stellar Duets February 18 th, 2005 VLT: dust emission at 3.5  m He VLT/NACO L band

Slide 36Stellar Duets February 18 th, 2005 He VLT/NACO M band VLT: dust emission at 4.8  m

Slide 37Stellar Duets February 18 th, 2005 He VLT/MIDI 8.7  m VLT: dust emission at 8.7  m VLT Interferometer MIDI resolution 7mas Double-dust project with Olivier Chesneau

Slide 38Stellar Duets February 18 th, 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 39Stellar Duets February 18 th, 2005 Further impact of AGB binarity Prevention of 3 rd -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

Slide 40Stellar Duets February 18 th, 2005 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 41Stellar Duets February 18 th, 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

Slide 42Stellar Duets February 18 th, 2005 Thank you!

Slide 43Stellar Duets February 18 th, 2005 Thank you!

Slide 44Stellar Duets February 18 th, 2005 Thank you!

Slide 45Stellar Duets February 18 th, 2005

Slide 46Stellar Duets February 18 th, 2005 He2-138 HST/Ha (R. Sahai) Inner parts of the PN

Slide 47Stellar Duets February 18 th, 2005 # of stars in the Galaxy: (Duquennoy & Mayor 1991: ~60% binaries) Primaries w/ lifetime shorter than age of the universe: yr Primaries w/ companion < 500 Ro: (Duquennoy & Mayor: ~25%) Mean age of stars: 10 Gyr PN visibility time: < 50,000 yr # of PN with close binary central stars: < 12,500 # of PN in the Galaxy: 10,000 +/ (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 48Stellar Duets February 18 th, 2005 TP10 simulation: density contour plot 68% of envelope lost in ~10 yr. Final configuration highly bipolar Orbital plane Perp. plane 1000 days 2000 days 3000 days 4000 days