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