SN progenitorsof binary stars
Fabian Schneider1,2

1Heidelberg Institute for Theoretical Studies
2Center for Astronomy, Heidelberg University

MIAPbP Garching, Interacting Supernovae, 9 Feb 2023

Sana et al. 2012

Most massive stars
exchange mass withcompanion during life

→ Most supernovae
from binary products!

2 M☉

e.g. Kobulnicky & Fryer 2007, Mason+2009, Sana+2012, 2013, Chini+2012, Kobulnicky+2014, Moe & Di Stefano 2017, …

Offner, Moe et al. 2022

Binary stars

2

Zero-age
main sequence

Binary stars
1st mass transfer
phase

1st supernova

Non-conservative masstransfer→ circumstellar material(from stripped star)➔SN kick!
High-mass
X-ray binary?!
2nd MT: commonenvelope phase(Partially) ejectedenvelope→ circumstellar material
2nd supernova(again from stripped star)

Double NS binary
Image credits: Thomas Tauris➔SN kick!

BH

3

Zero-age
main sequence

Binary stars
1st mass transferphase
Contact phase
1st supernova➔ closer initial orbit and/or
lower-mass companion

Non-conservative masstransfer→ circumstellar material(from stripped star)

High-mass
X-ray binary?!

Merged star

2nd MT: commonenvelope phase

Merger ejecta; LBV-likeSN progenitors→ circumstellar material(Partially) ejectedenvelope→ circumstellar material
2nd supernova(again from stripped star)

Magnetar formation?
Double NS binary
Image credits: Thomas Tauris

BH4

Zero-age
main sequence

Binary stars
1st mass transfer
phase
Contact phase
1st supernova(from stripped star)

Merged star

2nd MT: common-

1.

envelope phase

High-mass
X-ray binary?!

Merger ejecta; LBV-likeSN progenitors→ circumstellar material

2.

(Partially) ejectedenvelope→ circumstellar material

2nd supernova(again from stripped star)

Magnetar formation?
Double NS binary
Image credits: Thomas Tauris

BH5

and their supernova progenitors

Credit: ESO/L. Calçada

Stellar mergers

Light echoes ofV838 Mon

Stellar collision debris

When stars collide, they eject matter forming nebulae
Magnetic

Eta Carinae(e.g. Hirai+ 2021)

O6.5f?p star

HD 148937

SN1987A

Credit: NASA/ESA/Hubble

Questions:
1. How much of this is still around and2. How far away are ejecta whenmerged stars explode?
Credit: N. Smith, NASA/ESA
Recall: CSM ejected 10-100s yr before SN
with mass-loss rates 0.01-0.1 M☉/yr

Jason Pun (NOAO) and SINS Collaboration

7

Main-sequence (Case A) mergers▪ Experiment: mimic merger by
rapid accretion of material(rapid: tacc < tKH)

▪ Evolve stars to core collapse▪ Explode stars with semi-analytic,
ν-driven SN code of Müller+2016(c.f. other explodability criteria, e.g.
O‘Connor & Ott 2011, Ertl+2016, …)▪ Several Myr since merger→ no interaction with SN ejecta▪ Most models rejuvenate→ evolve like single stars
Schneider et al. 2023 (in prep.)

See also: Hellings 1983, 1984, Podsiadlowski & Joss 1989, Braun & Langer
1995 , Claeys et al. 2011, Vanbeveren et al. 2013, Justham et al. 2014

8

Post-main-sequence (early Case B) mergers▪ ~Myr since merger→ no interaction with SN ejecta▪ No rejuvenation→ Red or blue supergiants▪ RSG: similar to single stars butwith larger envelope mass
▪ BSG: thick (!), convective Hburning shell; core similar tooriginal single-star core
→ accretion threshold ΔMacc

Schneider et al. 2023 (in prep.)

See also: Hellings 1983, 1984, Podsiadlowski & Joss 1989, Braun & Langer
1995 , Claeys et al. 2011, Vanbeveren et al. 2013, Justham et al. 201410

Blue supergiant structure▪ Convective H-shell burning makes BSG (not only “small core for total mass”)▪ Core smaller after merger w.r.t single-star core, but grows again▪ Structure: “ZAMS star on top of helium star”

Schneider et al. 2023 (in prep.)11

Post-main-sequence (Case C) mergers▪ <104 yr since merger→ interacting SN possible→ but: fine tuning▪ No rejuvenation→ Red or blue supergiants▪ RSG: similar to single stars butwith larger envelope mass
▪ BSG: thick (!), convective Hburning shell; core similar tooriginal single-star core
→ accretion threshold ΔMacc
Schneider et al. 2023 (in prep.)

See also: Hellings 1983, 1984, Podsiadlowski & Joss 1989, Braun & Langer
1995 , Claeys et al. 2011, Vanbeveren et al. 2013, Justham et al. 201413

Death zones in Hertzsprung–Russell diagram
Single stars▪ Luminosity → core mass, *not* initial mass
▪ Teff→ average H mass fraction in envelope▪ BH formation: high core compactness/large
iron core mass/high central entropy/…

𝑀ΤM⨀𝜉𝑀 =𝑅(𝑀)Τ1000 kmBH
NS

Schneider et al. 2023 (in prep.)14

Death zones in Hertzsprung–Russell diagram
Single stars

Basinger et al. 2021

SN1987A

Schneider et al. 2023 (in prep.)

Disappearing star N6946-BH:
Red supergiant underwent outburst in2009 and since then disappeared➢location in HRD consistent withmodels in compactness peak15

Death zones in Hertzsprung–Russell diagram
Merged stars and accretors of binary mass transfer

LBV SN progenitors?
→ pre-SN eruption?
→ loss of entire H-rich envelope?

No such RSGs observed(Davies+2018)→ envelope instability?
→ CSM at SN explosion?

Likely no LBV-like mass loss
→ explosion as original single
star, but larger envelope mass

Schneider et al. 2023 (in prep.)

See also Justham et al. 201416

Explosion properties

Crosses: stars spend significant time in
S-Dor instability region → pre-SN CSM?!?

▪ Case A: explode as
single stars except if
incomplete
rejuvenation▪ Case B: explosion
energy & Ni mass as
single stars ofequivalent MCO, butejecta masses vary
▪ Case C: for MCO>5M☉, almost noexplosions if
significant accretion

Schneider et al. 2023 (in prep.)18

and bipolar nebulae

Credit: ESO/M. Kornmesser

Common-envelope evolution

Planetary nebulae
Many Planetary Nebulae likely result from
common-envelope interaction in binary systems(Paczynski 1976, Nordhaus & Blackman 2006, De Marco2009, Boffin+2012, Boffin & Jones 2019)Porb~1.2 dWD

WDPN Fleming I
Credit: ESO/H. Boffin (see Boffin+2012)

Collection by Judy Schmidt

23Common-envelope evolution

Patrick Ondratschek

Density▪ 0.97 M☉ early AGB giant (R~170 R☉)▪ 0.24 M☉ companion (e.g. MS star)▪ Core of giant and companion orbit incommon-envelope and are subject
to drag forces→ dynamical inspiral→ final orbital separation: ~25 R☉(~16.3 d orbital period)▪ Recombination enables entire
envelope ejection▪ Strong amplification of B-fields
Ondratschek+2022

24

Common-envelope evolution▪ Magnetic fields unimportant fororbital evolution and envelope
ejection▪ But: they drive bipolar, jet-likeoutflow➔ shape of planetary nebula▪ Outflow not launched from disk,
but from core binary▪ Blandford-Payne mechanismand magnetic tower jets
More universal process:X-ray binaries, SN Ia, CVs,gravitational-wave merger, …
Ondratschek+202225

CE evolution: massive stars

Marco Vetter

Vetter et al. 2023 (in prep.)▪ Same model as inMoreno et al. 2022
▪ Initially 10 M☉ post coreHe-burning primary starwith 5 M☉ companion(e.g. BH)

▪ Formation of jet-like,bipolar outflow▪ Bipolar outflow helps
eject envelope (~10%)26

CE evolution: massive stars▪ Bipolar outflow:▪ 5x10-5 M☉/d for ~104 d▪ Total mass ~0.5 M☉▪ Typical velocities ~100–200 km/s
▪ “Spherical” CE ejecta:▪ Total mass ~5.5 M☉▪ Typical velocities ~10–20 km/s
▪ Formation of circumbinary disk (mass & lifetime unclear)▪ Former primary explodes in 6x104 yr▪ Second mass-transfer phase onto BH companion▪ Non-conservative RLOF → mass loss from binary➔Aspherical, H/He-rich CSM when star explodes in SN Ib➔Timing/fine-tuning problem: eject CSM <100 yr before SN28

Circumventing the fine-tuning problem▪ Idea: trigger explosion by CE phase and/or merger→ Chevalier 2012
→ No mention of explosion mechanism▪ Option 1: NS/BH companion accretes during CE phase→ accretion-induced explosion (Schroeder+ 2022)▪ Option 2: core merger of two WDs→ thermonuclear explosion (see next slide)▪ Option 3: core merger of NS/BH + He/CO core
→ TZ object? Thermonuclear explosion?

What are possible rates andcan they constrain suchmodels? Other ideas?

▪ Option 4: mergers of MS/HG stars with NS/COWD/ONeMg WD/…
29

Javier Moran Fraile

Circumventing the fine-tuning problem
Failed/partial CE ejection & core mergers▪ What happens if core of primary merges with inspiralling companion?
→ can trigger thermonuclear explosion for two white dwarfs (double detonation)→ here: 0.6 M☉ CO white dwarf (companion) spiralling towards 0.4 M☉ He WD-core→ Explosion energy ~6x1050 erg, Ni mass ~0.01 M☉
Moran Fraile et al. 2023 (in prep.)▪ SN2002ic: Type Ia explosion from AGB progenitor with strong H-emission (Hamuy et al. 2003

30

Summary▪ Interacting SNe from binaries▪ Binary stars lead toaspherical, bipolar ejecta
with properties adequate
for interacting SNe▪ Stellar mergers▪ Common-envelopeevolution▪ Non-conservative masstransfer▪ …
➔ Timing problem▪ Stellar mergers from▪ Case A: rejuvenation→ evolves as single star
→ unstable RSGs?
▪ Case B & C: SNe from blue
supergiants possible→ massive envelopes→ cores similar to primary→ some explode as LBVs
→ Case-C timing possible?
→ cf. SN 1987A▪ Common-envelope
evolution gives rise to▪
▪
▪
▪
▪

bipolar, jet-like outflows
Magnetically driven
Bipolar outflow can containsignificant amount of mass
Most mass in equatorial
structure/torus/disk
Circumbinary disk + RLOFTiming: Case C? Coremergers, e.g. WDs!

Credit: ESO/M. Kornmesser/S.E. de Mink

▪ Interacting supernovae, main constraints▪ CSM ejected 10s-100s yr before SN▪ Most stars are in binaries and other multiples▪ Inferred mass-loss rates 0.01-0.1 M☉/yr→ Binary mass exchange▪ SN IIn rate ~5-10% of CCSNe→ E.g. almost all SNe from binary products▪ Huge diversity of SN types