Mass Transfer in Binary Stars
Robert Izzard
AIfA, Bonn Co-conspirators
Tyl Dermine, Ross Church, Shazrene Mohamed, Selma de Mink, ULB Lund Bonn Utrecht/Bonn/STScI
Ines Brott, Norbert Langer, Sung-Chul Yoon, VLT/FLAMES team Utrecht Utrecht/Bonn Bonn ULB (Jorissen) EU
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 2 / 64 1. Why do we care about Binary Stars? 2. Single vs Binary Evolution 3. RLOF vs Wind Accretion 4. e.g. Wind mass transfer: Barium Stars 5. e.g. RLOF in Massive Stars 6. Where do I (we?) go next?
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 3 / 64 Night Sky
80 Yale Bright Star Catalogue, Stars Brighter than 5th Mag 60 40 20 0 -20 -40 Declination (Latitude) -60 -80 0 5 10 15 20 Right Ascension (Longitude)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 4 / 64 Night Sky Binaries
80 Yale Bright Star Catalogue, Stars Brighter than 5th Mag 60 40 20 0 -20 -40 Declination (Latitude) -60 -80 0 5 10 15 20 Right Ascension (Longitude)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 5 / 64 Night Sky Binaries
80 Yale Bright Star Catalogue, Stars Brighter than 5th Mag
60 Mizar Capella 40 Algol Castor 20 Arcturus Regulus Procyon 0 Rigel Sirius -20 Antares -40 Declination (Latitude) -60 -80 0 5 10 15 20 Right Ascension (Longitude)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 6 / 64 Useful numbers
Stars brighter than 5th magnitude in Yale catalogue ◮ 1618 star systems ◮ 825 single-star systems ◮ 793 binary-star systems ◮ 793 % Binary System Fraction = 1618 = 49 ◮ 51 single stars : 98 stars in binaries ◮ Binary Star Fraction 793×2 1586 % = 825+793×2 = 2411 = 66
◮ Most stars are in binaries!
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 7 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why Binaries?
◮ Accurate stellar masses, radii, luminosities ◮ Gamma-ray bursts: long and short, very old! (z ∼ 8) ◮ Type Ia supernovae: Standard candles (?) Tell us Universe is expanding? ◮ Galactic Chemical Evolution: SN Ia, Ic, novae ◮ Stellar mergers ◮ X-ray binaries, CVs, AM CVns (grav waves) ◮ Chemically peculiar stars (my favourites!) ◮ Vital to understanding galaxies, stellar clusters, star formation, even cosmology. . .
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 8 / 64 Why are binaries so different? Why are binaries so different?
Compare:
Single star evolution
Binary star evolution
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 9 / 64 Why are binaries so different? Single Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 10 / 64 Why are binaries so different? Single Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 11 / 64 Why are binaries so different? Single Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 12 / 64 Why are binaries so different? Single Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 13 / 64 Why are binaries so different? Single Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 14 / 64 Why are binaries so different? Binary Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 15 / 64 Why are binaries so different? Binary Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 16 / 64 Why are binaries so different? Binary Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 17 / 64 Why are binaries so different? Binary Star Evolution
Time/Gyr → Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 18 / 64 Binary Interaction What happens next? Transfer of 1. Mass M 2. Angular Momentum J
0 2 4 6 8 10 log10 Period/days
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 19 / 64 Binary Interaction RLOF What happens next? 1. Close binary: Roche-lobe overflow 2. . . .
Roche Lobe Over Flow
0 2 4 6 8 10 log10 Period/days
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 20 / 64 Binary Interaction RLOF Close binary: Roche-lobe Overflow
Roche Lobe overflow ∆M and ∆J spin up +tides Play Ross Church’s movies
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 21 / 64 Binary Interaction RLOF Often not “conservative”: Common Envelope
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 22 / 64 Binary Interaction RLOF Chemical peculiarities ???
White Dwarf + Chemically Normal? Star Massive stars: WD→NS or BH
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 23 / 64 Binary Interaction Wind accretion What happens next? 1. Close binary: Roche-lobe overflow 2. Distant binary: Wind accretion
Wind Accretion
0 2 4 6 8 10 log10 Period/days
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 24 / 64 Binary Interaction Wind accretion Distant Binary: Wind Accretion
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 25 / 64 Binary Interaction Wind accretion Wind Accretion: Giant Wind
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 26 / 64 Binary Interaction Wind accretion Wind Accretion: Gravitational Focusing
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 27 / 64 Binary Interaction Wind accretion Wind Accretion: Accretion
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 28 / 64 Binary Interaction Wind accretion Wind Accretion 6: Primary Death
White Dwarf + Chemically Peculiar Star
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 29 / 64 Binary Interaction Oh dear So we understand it all?
◮ At a qualitative level, yes. . . (perhaps) ◮ But quantitatively . . . little agreement between models and observations! Two examples for you: 1. Barium stars
◮ Low mass 1 − 3M⊙ ◮ Wind accretion ◮ Complete observation set: [Ba/Fe], P and e 2. Massive main sequence stars
◮ High mass > 10M⊙ ◮ Roche lobe overflow ◮ Observation set expanding rapidly
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 30 / 64 Barium Stars What is a barium star?
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 31 / 64 Barium Stars How to make a Ba star?
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 32 / 64 Barium Stars The barium star now
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 33 / 64 Barium Stars Tidal Circulari[sz]ation τ ∼ (separation/radius)8
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 34 / 64 Barium Stars Observations: GK giants (Jorissen data) Period / days 100 1000 10000 0.9 0.8 0.7 0.6 0.5 0.4
Eccentricity 0.3 0.2 0.1 0
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 35 / 64 Barium Stars Expected result for Ba stars Period / days 100 1000 10000 0.9 0.8 Circularization! 0.7 0.6 0.5 0.4
Eccentricity 0.3 0.2 0.1 0 Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 36 / 64 Barium Stars Not what we see! They are eccentric Period / days 100 1000 10000 1 0.9 0.8 0.7 0.6 0.5 0.4 Eccentricity 0.3 0.2 0.1 0 Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 37 / 64 Barium Stars Confirmed in canonical model
1
0.8
0.6
0.4 Eccentricity
0.2
0
2 3 4 5 log10(Period/days)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 38 / 64 Barium Stars What is happening?
TPAGB 0.5 End AGB 0.4 Tides
0.3
0.2 Eccentricity
0.1
0
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 Time
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 39 / 64 Barium Stars What is happening?
TPAGB 0.5 End AGB 0.4 Tides
0.3
e-pumping 0.2 Eccentricity
0.1
0
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 Time
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 40 / 64 Barium Stars What is happening?
TPAGB 0.5 End AGB 0.4 Tides
0.3
e-pumping 0.2 Eccentricity
0.1 Kick ? 0
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 Time
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 41 / 64 Barium Stars Solution 1: Kick The WD
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 42 / 64 Barium Stars Not Crazy! Seen in GCs (Davis et al.)
Young WD
Single and binary stars!
Old WD/MS
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 43 / 64 Barium Stars Apply WD kick 4 kms−1 Still Problems!
1
0.8 Long-P tail
0.6
0.4
Eccentricity Period gap!
0.2
0
2 3 4 5 log10(Period/days)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 44 / 64 Barium Stars 4km/s kick+efficient CE ejection
1
0.8
0.6
0.4 Eccentricity
0.2
0
2 3 4 5 log10(Period/days)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 45 / 64 Barium Stars
4km/s kick + efficient CEE and −∆Jorb
1
0.8
0.6
0.4 Eccentricity
0.2
0
2 3 4 5 log10(Period/days)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 46 / 64 Barium Stars Solution 1: How To Make Ba Stars...?
Izzard, Church and Dermine 2010 (A&A accepted)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 47 / 64 Barium Stars Solution 2: Circumbinary Disk?
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 48 / 64 Barium Stars Some eccentricity, same old problems?
1
0.8
0.6
0.4 Eccentricity
0.2
0
100 1000 104 105 Period/days Dermine et al. (in preparation)
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 49 / 64 Barium Stars Wind Mass Transfer? e.g. Mira
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 50 / 64 Barium Stars Play movies
Play Shazrene Mohamed’s movies
Morris et al. 2004, Mauron & Huggins 2006
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 51 / 64 Barium Stars Wind OverFlow?
Roche WOF?Wind Lobe Accretion Over Flow
0 2 4 6 8 10 log10 Period/days
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 52 / 64 Massive Stars RLOF (in Massive Stars)
L1
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 53 / 64 Massive Stars RLOF (in Massive Stars) ◮ Often “conservative”: Spin up is important! 1.4 M =20 M M =16 M P=4 days 1.2 1 ⊙ 2 ⊙ Case A RLOF 1 0.8 crit v /
v 0.6 0.4 0.2 0 15.8 16 16.2 16.4 16.6
M2/M⊙
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 54 / 64 Massive Stars Spun Up Massive Stars
Why are they interesting?
Rotation→Instabilities→Mixing
In low-mass stars: τrotational mixing ≪ τH-burning
In massive stars: ∼ τrotationalmixing τH-burning
1. H-burnt material (He,N) at the surface! “Chemically homogeneous” 2. Smaller stars
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 55 / 64 Massive Stars Sung-Chul Yoon’s Movies
Single stars, M = 20 M⊙, Z = 0.05Z⊙
v v % v v % / crit = 15 / crit = 60
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 56 / 64 Massive Stars At Critical Rotation Mass cannot be accreted → lost to interstellar medium!
unprocessed
mildly processed
processed Ejected material: He, N, Na, Al ↑ C, O, Mg ↓
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 57 / 64 Massive Stars Consequences for Globular Clusters Stars in Globular Clusters have O-Na and Al-Mg anticorrelations
Caretta et al. 2009
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 58 / 64 Massive Stars Are massive binaries responsible?
De Mink et al. 2009
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 59 / 64 Observations→Problems Before you get comfortable
1. We do not understand mixing, e.g.: ◮ rotation ◮ magnetic fields ◮ thermohaline etc. 2. We do not understand how binaries affect the big picture: ◮ Spin Up: RLOF, tides, more mixing? ◮ Spin Down: Wind, tides, less mixing? 3. Main sequence models are wrong 4. We cannot always see that they are binaries 5. CONNECTED PROBLEMS: all related to each other
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 60 / 64 Observations→Problems e.g. Nitrogen in B type stars Obs: VLT-FLAMES survey of Massive (B/MS) Stars (Hunter et al. 2008/9) vs Models of rotating single stars from Ines Brott (et al. in preparation)
8 Binaries?
7.8
7.6 Mass
7.4 Transfer?
7.2
7
12 + log [N/H] These are 6.8 Main Sequence Stars: 0 50 100 150 200 250 300 350 v sini [km/s] “Understood”! M ≤ 10 M 12 < M ≤ 15 M M > 20 M ≤ sun ≤ sun sun 10 < M 12 Msun 15 < M 20 Msun binary § ¤ 3 ADVERTISEMENT: VLT Tarantula survey coming out soon: 10 stars! ¦ ¥ Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 61 / 64 Observations→Problems
Close binary evolution: 20M⊙+15M⊙ 18 16 14 3. single rapid rotator / rapid rotator + NS companion 2. rapid 12 rotat or 10 s: + ass low mass He star companion ger er 8 g m nsf tra 1. mer oin
Time (Myr) 6 ong 4 onset mass transfer 2 and spin up of accretor detached binaries 0 1 2 3 4 5 5 10 100 1000 10000 Initial orbital period (days)
Calculated by Selma de Mink with binary_c/nucsyn population synthesis code.
http://www.astro.uni-bonn.de/~izzard/binary_c.html
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 62 / 64 Observations→Problems
Close binary evolution: 20M⊙+15M⊙ Time (Myr) One or both stars Detectable as binary by are fast rotators radial velocity variations 18 16 M1 = 20 Msun M2 = 15 Msun 14 Post mass transfer 12 fast rotating accretor 10 g oin er ong 8 s ansf s tr ger 6 mas Mer 4 p n u pre mass transfer al spi 2 tid 0 1 2 3 4 5 5 10 100 1000 10000 Initial orbital period (days)
Calculated by Selma de Mink with binary_c/nucsyn population synthesis code.
http://www.astro.uni-bonn.de/~izzard/binary_c.html
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 63 / 64 Observations→Problems Where do I/we go from here?
New Observations Stellar models: VLT Tarantula etc. Mixing Nucleosynthesis
Hydro models: Understand Mass Transfer Physics of Stellar Mergers Stars
Robert Izzard (AIfA, Bonn) Mass Transfer in Binary Stars 64 / 64