Nucleosynthesis in Pop III / II (rotating) massive stars
and the chemical compositionof observed metal-poor stars
Arthur Choplin
Konan University, Japan

Collaborators:
N. Tominaga (Konan), G. Meynet (Geneva), R. Hirschi (Keele),
M. Ishigaki (Tohoku), S. Ekström (Geneva), A. Skuladottir (MPIA),
A. Laird (York), C. Chiappini (AIP), A. Maeder (Geneva)

November 11th
NagoyaFirst
stars

H

He

~ 0.2 Gyr13.8 Gyr

1Time

Firststars

H

What are their properties ?
He—> Origin of the elements—> First supernovae—> Reionization—> …

~ 0.2 Gyr13.8 Gyr

1Time

First(massive)stars

H

Metal-free(no carbon, oxygen…)

Predominantly
massive (> 10 M⊙)
Bromm et al. (2002),
Abel et al. (2002),
Omukai et al. (2003)
Yoshida et al. (2006)
Susa (2013),
Hirano et al. (2014) …

He~ 0.2 GyrFirst stars

Synthesized first metals(carbon, oxygen,…)

13.8 Gyr

1Time

FirstFirst(massive) chemicalenrichment
stars

Metal-free(no carbon, oxygen…)

First stars

C

H

N

Predominantly
massive (> 10 M⊙)

O

HeBromm et al. (2002),
Abel et al. (2002),
Omukai et al. (2003)
Yoshida et al. (2006)
Susa (2013),
Hirano et al. (2014) …

Mg

Synthesized first metals(carbon, oxygen,…)Fe
Massive stars Zn
have short lifetimes~ 0.2 Gyr13.8 Gyr

1Time

FirstFirst(massive) chemicalenrichment
stars

2nd
generation

C

H

N
O

He

Mg
Fe

Massive stars Zn
have short lifetimes~ 0.2 Gyr

~ 0.5 Gyr1

13.8 GyrTimeFirstFirst(massive) chemicalenrichment
stars

2nd
generation

C

H

N
O

He

Mg
Fe

Massive stars Zn
have short lifetimes~ 0.2 Gyr

~ 0.5 Gyr

metal-free

metal-poor

1

13.8 GyrTimeFirstFirst(massive) chemicalenrichment
stars

2nd
generation

CHN
3rd generation,
4th generation,
…

O

He

Mg
Fe

Massive stars Zn
have short lifetimes~ 0.2 Gyr

~ 0.5 Gyr

metal-free

metal-poor

1

13.8 GyrTimeFirstFirst(massive) chemicalenrichment
stars

2nd
generationCH

Low mass stars have long lifetimes

N
3rd generation,
4th generation,
…

O

He

Mg
Fe

Massive stars Zn
have short lifetimes~ 0.2 Gyr

~ 0.5 Gyr

metal-free

metal-poor

1

13.8 GyrTimeFirstFirst(massive) chemicalenrichment
stars

2generationCH

Low mass stars have long lifetimes

N
3rd generation,
4th generation,
…

O

He

Mix of different generations
old low mass stars
still alive around us

nd

Mg
Fe

Massive stars Zn
have short lifetimes~ 0.2 Gyr

~ 0.5 Gyr

metal-free

metal-poor

1

13.8 GyrTimeFirstFirst(massive) chemicalenrichment
stars

nd

2
generationCH

Low mass stars have long lifetimes> 500 stars observed with [Fe/H] < -3

N

Extremely metal poor (EMP) stars(no metal-free star observed)
3rd generation, from SAGA database, Suda et al.
4th generation,
…

O

He

Mix of different generations
old low mass stars
still alive around us

MgFe

Massive stars Zn
have short lifetimes~ 0.2 Gyr

~ 0.5 Gyr

metal-free

metal-poor

13.8 GyrTime[ ] : in log scale, relatively to the Sun
1

Observations of extremely metal-poor (EMP) stars
Chemical composition (abundances) of stars with [Fe/H] < -3

90th percentile

Medianlog(12C/13C)

10th percentile

data from SAGA database

Diverse chemical compositions

Suda et al 2008, 2017[ ] : in log scale, relatively to the Sun
2

Stellar archaeology
First
First
(massive) chemicalenrichment
stars

2generationCH

Low mass stars have long lifetimes> 500 stars observed with [Fe/H] < -3

N

Extremely metal poor (EMP) stars(no metal-free star observed)
3rd generation,
4th generation,
…

O

He

Mix of different generations
old low mass stars
still alive around us

ndfrom SAGA database, Suda et al.

Mg
Fe
Zn

~ 0.2 Gyr

~ 0.5 Gyr13.8 Gyr[Fe/H] = -∞[Fe/H] ≲ -3

[Fe/H] = 0

3

Time

Stellar archaeology
First
First
(massive) chemicalenrichment
stars

2generationCH

Low mass stars have long lifetimes> 500 stars observed with [Fe/H] < -3

N

Extremely metal poor (EMP) stars(no metal-free star observed)
3rd generation,
4th generation,
…

O

He

Mix of different generations
old low mass stars
still alive around us

ndfrom SAGA database, Suda et al.

Mg
Fe
Zn

Chemical composition of metal-poor stars:~ 0.2 Gyr
~ 0.5 Gyr13.8 Gyrwindow on
first (early) massive stars[Fe/H] = -∞[Fe/H] -3[Fe/H] = 0

≲

3

Time

Stellar evolution models—> to predict the yields

First
First
(massive) chemicalenrichment
stars

H

Low mass stars have long lifetimes

N
3rd
4th

O

H

Mix of different generations
old low mass stars
still alive around us

2
generation

C

Zero + low
metallicity models

…

Mg
Fe
Zn

~ 0.2 Gyr

~ 0.5 Gyr13.8 Gyr[Fe/H] = -∞[Fe/H] ≲ -3

[Fe/H] = 0

3

Time

stars with [Fe/H] < -3

What kind of massive star models
can account for the chemical compositionof (extremely) metal-poor stars ?
90

Medianlog(

10data from SAGA database
Suda et al 2008, 2017

What is the nature of the first massive stars ?
—> Deduced from (some) EMP stars(list is not complete)

Umeda & Nomoto 2003, 2005, Iwamoto+2005, Ito+2013,
Tominaga+2007, 2014, Kobayashi+2014, Ishigaki+2014•

Mixing & Fallback + faint SN•(Fast) rotating stars•

Massive metal-free stars of :•Weak SN from a 60 Mo Pop. III•

Normal SN (15 Mo) + faint SN with fallback (35 Mo)•

Jet-induced SN from 25 - 40 Pop. III star•

Rotation + faint SN•

Rotating 15-40 Mo Pop. III•

Rotation + late mixing + faint SN•

Convective shell interactions

Meynet+2006, Hirschi 2007, Cescutti+2013, Maeder+2015, Choplin+2016
Heger & Woosley 2010. Also Frebel+2015, Placco+2015, 2016, Chen+2017
Keller+2014, model from Joggerst+2009
Limongi+2003

Maeda & Nomoto 2003, Tominaga 2009

Takahashi+2014, Choplin+2019
Joggerst+2010
Choplin+2017
Banerjee+2018, Clarkson+2018

4What is the nature of the first massive stars ?
—> Deduced from (some) EMP stars(list is not complete)

Umeda & Nomoto 2003, 2005, Iwamoto+2005, Ito+2013,
Tominaga+2007, 2014, Kobayashi+2014, Ishigaki+2014•

Mixing & Fallback + faint SN•(Fast) rotating stars•

Massive metal-free stars of :•Weak SN from a 60 Mo Pop. III•

Normal SN (15 Mo) + faint SN with fallback (35 Mo)•

Jet-induced SN from 25 - 40 Pop. III star•

Rotation + faint SN•

Rotating 15-40 Mo Pop. III•

Rotation + late mixing + faint SN•

Convective shell interactions

Meynet+2006, Hirschi 2007, Cescutti+2013, Maeder+2015, Choplin+2016
Heger & Woosley 2010. Also Frebel+2015, Placco+2015, 2016, Chen+2017
Keller+2014, model from Joggerst+2009
Limongi+2003

Maeda & Nomoto 2003, Tominaga 2009

Takahashi+2014, Choplin+2019
Joggerst+2010
Choplin+2017
Banerjee+2018, Clarkson+2018

4

Mixing&FallbackWhat is the nature of the first massive stars ?
—> Deduced from (some) EMP stars(list is not complete)

Umeda & Nomoto 2003, 2005, Iwamoto+2005, Ito+2013,
Tominaga+2007, 2014, Kobayashi+2014, Ishigaki+2014•

Mixing & Fallback + faint SN•(Fast) rotating stars•

Massive metal-free stars of :•Weak SN from a 60 Mo Pop. III•

Normal SN (15 Mo) + faint SN with fallback (35 Mo)•

Jet-induced SN from 25 - 40 Pop. III star•

Rotation + faint SN•

Rotating 15-40 Mo Pop. III•

Rotation + late mixing + faint SN•

Convective shell interactions

Meynet+2006, Hirschi 2007, Cescutti+2013, Maeder+2015, Choplin+2016
Heger & Woosley 2010. Also Frebel+2015, Placco+2015, 2016, Chen+2017
Keller+2014, model from Joggerst+2009
Limongi+2003

Maeda & Nomoto 2003, Tominaga 2009

Takahashi+2014, Choplin+2019
Joggerst+2010
Choplin+2017
Banerjee+2018, Clarkson+2018

4

RotationWhat is the nature of the first massive stars ?
—> Deduced from (some) EMP stars(list is not complete)

Umeda & Nomoto 2003, 2005, Iwamoto+2005, Ito+2013,
Tominaga+2007, 2014, Kobayashi+2014, Ishigaki+2014•

Mixing & Fallback + faint SN•(Fast) rotating stars•

Massive metal-free stars of :•Weak SN from a 60 Mo Pop. III•

Normal SN (15 Mo) + faint SN with fallback (35 Mo)•

Jet-induced SN from 25 - 40 Pop. III star•

Rotation + faint SN•

Rotating 15-40 Mo Pop. III•

Rotation + late mixing + faint SN•

Convective shell interactions•

Mass transfer from an AGB-companion Suda+2004, Suda & Fujimoto 2010•

Self-enrichement•

Dust-gas around CEMP-no

Meynet+2006, Hirschi 2007, Cescutti+2013, Maeder+2015, Choplin+2016
Heger & Woosley 2010. Also Frebel+2015, Placco+2015, 2016, Chen+2017
Keller+2014, model from Joggerst+2009
Limongi+2003

Maeda & Nomoto 2003, Tominaga 2009

Takahashi+2014, Choplin+2019
Joggerst+2010
Choplin+2017
Banerjee+2018, Clarkson+2018

Fujimoto+2000

Event during
the EMP star life
Other scenarios

Venn+2014

4

What is the nature of the first massive stars ?
—> Deduced from (some) EMP stars(list is not complete)

Umeda & Nomoto 2003, 2005, Iwamoto+2005, Ito+2013,
Tominaga+2007, 2014, Kobayashi+2014, Ishigaki+2014•

Mixing & Fallback + faint SN•(Fast) rotating stars•

Massive metal-free stars of :•Weak SN from a 60 Mo Pop. III•

Normal SN (15 Mo) + faint SN with fallback (35 Mo)•

Jet-induced SN from 25 - 40 Pop. III star•

Rotation + faint SN•

Rotating 15-40 Mo Pop. III•

Rotation + late mixing + faint SN•

Convective shell interactions•

Mass transfer from an AGB-companion Suda+2004, Suda & Fujimoto 2010•

Self-enrichement•

Dust-gas around CEMP-no

Meynet+2006, Hirschi 2007, Cescutti+2013, Maeder+2015, Choplin+2016
Heger & Woosley 2010. Also Frebel+2015, Placco+2015, 2016, Chen+2017
Keller+2014, model from Joggerst+2009
Limongi+2003

Maeda & Nomoto 2003, Tominaga 2009

Takahashi+2014, Choplin+2019
Joggerst+2010

Still debated—> importance of mixing

Choplin+2017
Banerjee+2018, Clarkson+2018

Fujimoto+2000

Event during
the EMP star life
Other scenarios

Venn+2014

4

What is the nature of the first massive stars ?
—> Deduced from (some) EMP stars(list is not complete)

Umeda & Nomoto 2003, 2005, Iwamoto+2005, Ito+2013,
Tominaga+2007, 2014, Kobayashi+2014, Ishigaki•

Mixing & Fallback + faint SN•(Fast) rotating stars•

Massive metal-free stars of :•Weak SN from a 60 Mo Pop. III•

Normal SN (15 Mo) + faint SN with fallback (35 Mo)•

Jet-induced SN from 25 - 40 Pop. III star•

Rotation + faint SN•

Rotating 15-40 Mo Pop. III•

Rotation + late mixing + faint SN•

Convective shell interactions•

Mass transfer from an AGB-companion Suda+2004, Suda & Fujimoto 2010•

Self-enrichement•

Dust-gas around CEMP-no

Meynet+2006, Hirschi 2007, Cescutti+2013, Maeder+2015, Choplin+2016
Heger & Woosley 2010. Also Frebel+2015, Placco+2015, 2016,
Keller+2014, model from Joggerst+20
Limongi+2003

Maeda & Nomoto 2003

Takahashi+2014, Choplin+2019
Joggerst+2010

Still debated—> importance of mixing

Choplin+2017
Banerjee+2018, Clarkson+2018

Fujimoto+

Event during
the EMP star life
Other scenarios

Venn+2014

4

Rotating massive stars
Observation of 496 nearby
massive (OB) stars
Huang & Gies (2006)

3 x 10-3

2 x 10-3

1 x 10-3

5Rotating massive stars
Observation of 496 nearby
massive (OB) stars
Huang & Gies (2006)

3 x 10-3

2 x 10-3

Surface andinternal effects

1 x 10-3

5Surface effects of rotation (massive stars)
Mass loss• Mechanical mass loss—> when gravity = centrifugal effect

6

Surface effects of rotation (massive stars)
Mass loss• Mechanical mass loss—> when gravity = centrifugal effect• Radiatively driven stellar winds—> anisotropies => polar + equatorial ejections—> surface enrichments C, N, O…

(Hirschi 2007)

6(Owocki 1996, Maeder+1999, 2000)

Surface effects of rotation (massive stars)
Mass loss• Mechanical mass loss—> when gravity = centrifugal effect• Radiatively driven stellar winds—> anisotropies => polar + equatorial ejections—> surface enrichments C, N, O…

• Surface(Owocki 1996, Maeder+1999, 2000)(Hirschi 2007)

Roche model

deformation
Achernar, ~10 M⊙

from interferometry :—> Req / Rp ~ 1.5—> at critical velocity
De Souza et al. (2003)
Carfiofi et al. (2008)
Ekstrom (2008)

6

Internal effects of rotation (massive stars)• Meridional circulation (or Eddington–Sweet
circulation)• Shear mixing

Brueggen+2001
Maeder+2000• Transport of angular momentum• Transport of chemical elements

7

Internal effects of rotation (massive stars)• Meridional circulation (or Eddington–Sweet
circulation)• Shear mixing

𝝉 ~ 105 years𝝉 ~ 105 years

Brueggen+2001
Maeder+2000• Transport of angular momentum• Transport of chemical elements

7

Internal effects of rotation (massive stars)• Meridional circulation (or Eddington–Sweet
circulation)• Shear mixing

𝝉 ~ 105 years𝝉 ~ 105 years

Brueggen+2001
Maeder+2000

Full life/scale of stars—> only in 1D…

• Transport of angular momentum• Transport of chemical elements

7

Internal effects of rotation (massive stars)• Meridional circulation (or Eddington–Sweet
circulation)• Shear mixing

𝝉 ~ 105 years𝝉 ~ 105 years

Brueggen+2001
Maeder+2000

Full life/scale of stars—> only in 1D…

• Transport of angular momentum• Transport of chemical elements

strong horizontal turbulence=> Ω constant on isobars=> ~ Ω(r)=> shellular rotation (1D approx.)Dh >> Dv

Zahn (1992), Maeder book (2008), …

Dv
7Internal effects of rotation (massive stars)• Meridional circulation (or Eddington–Sweet
circulation)• Shear mixing

𝝉 ~ 105 years𝝉 ~ 105 years

Brueggen+2001
Maeder+2000

Full life/scale of stars—> only in 1D…

• Transport of angular momentum• Transport of chemical elements

strong horizontal turbulence=> Ω constant on isobars=> ~ Ω(r)diffusive equation=> shellular rotation (1D approx.)Dh >> Dv

Zahn (1992), Maeder book (2008), …

Dv
7advective + diffusive equation

Internal effects of rotation (massive stars)• Meridional circulation (or Eddington–Sweet
circulation)• Shear mixing

𝝉 ~ 105 years𝝉 ~ 105 years
scalesscaleswith ~ dΩ / drwith ~ ΩBrueggen+2001
Maeder+2000

Full life/scale of stars—> only in 1D…

• Transport of angular momentum• Transport of chemical elements

strong horizontal turbulence=> Ω constant on isobars=> ~ Ω(r)diffusive equation=> shellular rotation (1D approx.)Dh >> Dv

Zahn (1992), Maeder book (2008), …

Dv
7advective + diffusive equation

Stellar evolution with rotation

Z = Z⊙(solar metallicity)

Observed OB (massive) stars
60vs.

log (N/C)

40

Martins+15

25
20

log g

8

20 - 60 M⊙ rotating models

Stellar evolution with rotation

Z = Z⊙(solar metallicity)

Observed OB (massive) stars
60vs.

log (N/C)

40

20 - 60 M⊙ rotating models

25
20—> CNO cycle in the core—> N / C increases in the core—> rotational mixing—> N / C increases at the surface
Martins+15

log g

8

Stellar evolution with rotation

Z = Z⊙(solar metallicity)

Observed OB (massive) stars
60vs.

log (N/C)

40

20 - 60 M⊙ rotating models

25

What happens
at low/zero metallicity? 20—> CNO cycle in the core—> N / C increases in the core—> rotational mixing—> N / C increases at the surface

Martins+15

log g

8

Z = 10-5

Nucleosynthesis in rotating massive stars[Fe/H] ~ -4

20 M☉ at the end of evolution (pre-SN)
No rotation

Rotation (vini ~ 600 km/s)

14

N

14

N

Rotation => Nitrogen (mixing between H- and He-burning regions)
Effect of rotation on nucleosynthesis:
e.g. Meynet+2002, Ekstrom+ 2008,
Pignatari+2008, Takahashi+2014,
Frischknecht+2016, Choplin+2018,
Chieffi+2018, Banerjee+2019…

9: convective zones

Z = 10-5

Nucleosynthesis in rotating massive stars[Fe/H] ~ -4

20 M☉ at the end of evolution (pre-SN)
No rotation

Rotation (vini ~ 600 km/s)

Inner layers
not muchaffectd by rot.
14

N

14

N

~ C-shell~ C-shell

Rotation => Nitrogen (mixing between H- and He-burning regions)
Effect of rotation on nucleosynthesis:
e.g. Meynet+2002, Ekstrom+ 2008,
Pignatari+2008, Takahashi+2014,
Frischknecht+2016, Choplin+2018,
Chieffi+2018, Banerjee+2019…

9: convective zones

Z = 10-5

Nucleosynthesis in rotating massive stars[Fe/H] ~ -4

20 M☉ at the end of evolution (pre-SN)
No rotation

Rotation (vini ~ 600 km/s)

Inner layers
not muchaffectd by rot.
14

N

14

N

~ 4 solar
masses~ C-shell~16 solar
masses~ C-shell

Rotation => Nitrogen (mixing between H- and He-burning regions)
Effect of rotation on nucleosynthesis:
e.g. Meynet+2002, Ekstrom+ 2008,
Pignatari+2008, Takahashi+2014,
Frischknecht+2016, Choplin+2018,
Chieffi+2018, Banerjee+2019…

9: convective zones

Z = 10-5

Nucleosynthesis in rotating massive stars[Fe/H] ~ -4

20 M☉ at the end of evolution (pre-SN)
No rotation

Rotation (vini ~ 600 km/s)

Inner layers
not muchaffectd by rot.

Yields?

Yields?

14

N

14

N

~ 4 solar
masses~ C-shell~16 solar
masses~ C-shell

Rotation => Nitrogen (mixing between H- and He-burning regions)
Effect of rotation on nucleosynthesis:
e.g. Meynet+2002, Ekstrom+ 2008,
Pignatari+2008, Takahashi+2014,
Frischknecht+2016, Choplin+2018,
Chieffi+2018, Banerjee+2019…

9: convective zones

explosion
Rotating massive stars yields (assumingwith strong fallback)
H
He
Core

Yields of
H+He layers

Z = 10-5[Fe/H] ~ -4

• ~ C - Mg yields boosted by rotation

Mcut ~ 4 - 5 M☉
vini [km s-1]

20 M☉

10

explosion
Rotating massive stars yields (assumingwith strong fallback)
H
He
Core

Yields of
H+He layers

Z = 10-5[Fe/H] ~ -4

• ~ C - Mg yields boosted by rotation

Mcut ~ 4 - 5 M☉
vini [km s-1]

20 M☉

Z=0

10

explosion
Rotating massive stars yields (assumingwith strong fallback)
H
He
Core

Yields of
H+He layers

Z = 10-5[Fe/H] ~ -4

• Trans-Fe yields boosted by rotation

Mcut ~ 4 - 5 M☉

20 M☉

vini [km s-1]

Rotation boosts theslow neutron
capture-process11explosion
Rotating massive stars yields (assumingwith strong fallback)
H
He
Core

Yields of
H+He layers

Z = 10-5[Fe/H] ~ -4

• Trans-Fe yields boosted by rotation

Mcut ~ 4 - 5 M☉

20 M☉

vini [km s-1]

Rotation boosts theslow neutron
capture-process

Z=0
x 106

(no s-process)11

explosion
Rotating massive stars yields (assumingwith strong fallback)
H
He
Core

Yields of
H+He layers
Mcut ~ 4 - 5 M☉

Z = 10-5[Fe/H] ~ -4

• Trans-Fe yields boosted by rotation

but strongly depend on metallicity

20 M☉

vini [km s-1]

Rotation boosts theslow neutron
capture-process

Z=0
x 106

(no s-process)11

Rotating massive stars yields

Z = 10-3[Fe/H] ~ -2

Effect of initial mass + rotation on trans-Fe elements yields

mid. rot88

Sr (x100)no rot.

138

Ba

208

Pb (/100)

Choplin et al. (2018)12

Rotating massive stars yields

Z = 10-3[Fe/H] ~ -2

Effect of initial mass + rotation on trans-Fe elements yields

88

Sr (x100)

mid. rotno rot.

138

Ba

208

Pb (/100)

Effect of rotation is more importantfor Mini < 60 M☉

Choplin et al. (2018)12

Rotating massive stars yields

Z = 10-3[Fe/H] ~ -2

Effect of initial mass + rotation on trans-Fe elements yields

88

Sr (x100)

mid. rotno rot.

faster rot.

138

Ba

208

Pb (/100)

Effect of rotation is more importantfor Mini < 60 M☉

Choplin et al. (2018)12

Rotating massive stars yields

Z = 10-3[Fe/H] ~ -2

Effect of initial mass + rotation on trans-Fe elements yields

88

Sr (x100)

mid. rotno rot.

faster rot.

138

Ba

208

Pb (/100)

Effect of rotation is more importantfor Mini < 60 M☉
Ba, (La, … Eu) yields boosted for high rot. (+ not too low Z)

Choplin et al. (2018)12

Chemical signatures of (fast) rotating massive stars
in metal-poor stars

Signature of fast rotating massive stars in metal-poor stars?
e.g. Choplin+2017,
Banerjee+2019

Fast rot. 40 Mo

CS29528-028
Abundances fromMid rot. 25 Mo

Fast rot. 25 Mo

No rot. 25 Mo

Aoki et al. 2007,
Allen et al. 2012

HE0336+0113
Abundances from

Fast rot. 40 Mo

13

Cohen 2006, 2013

Signature of fast rotating massive stars in metal-poor stars?
e.g. Choplin+2017,
Banerjee+2019

Fast rot. 40 Mo

CS29528-028
Abundances fromMid rot. 25 Mo

Fast rot. 25 Mo

No rot. 25 Mo

Aoki et al. 2007,
Allen et al. 2012

Smallest chi2 given
by a fast rot. 40 M☉
HE0336+0113
Abundances from

Fast rot. 40 Mo

13

Cohen 2006, 2013

Systematic comparison : rotating massive stars vs. EMP stars
Choplin, Tominaga & Ishigaki (2019)•••272 EMP with -4 < [Fe/H] < -3
Analysis of light elements (C - Al)
Evolutionnary effects in EMP => corrections(e.g. dredge up)

Placco et al. (2014)272 observed EMP stars

14

Systematic comparison : rotating massive stars vs. EMP stars
Choplin, Tominaga & Ishigaki (2019)•••272 EMP with -4 < [Fe/H] < -3
Analysis of light elements (C - Al)
Evolutionnary effects in EMP => corrections(e.g. dredge up)

Match?

•••

Placco et al. (2014)

20 M☉ , [Fe/H] = -3.8
8 initial rotations
Explo. with strong fallback

massive stars models

272 observed EMP stars

14

Systematic comparison : rotating massive stars vs. EMP stars
Choplin, Tominaga & Ishigaki (2019)•••272 EMP with -4 < [Fe/H] < -3
Analysis of light elements (C - Al)
Evolutionnary effects in EMP => corrections(e.g. dredge up)

Placco et al. (2014)

Match?

•

chi2 analysis••

20 M☉ , [Fe/H] = -3.8
8 initial rotations
Explo. with strong fallback

massive stars models

272 observed EMP stars>10 extract of the
8 x 272 table𝟀20

No rotation

Fast rotation
14

Systematic comparison : rotating massive stars vs. EMP stars
Choplin, Tominaga & Ishigaki (2019)•••272 EMP with -4 < [Fe/H] < -3
Analysis of light elements (C - Al)
Evolutionnary effects in EMP => corrections(e.g. dredge up)

Placco et al. (2014)

Match?

•

chi2 analysis••

20 M☉ , [Fe/H] = -3.8
8 initial rotations
Explo. with strong fallback

massive stars models

272 observed EMP stars>10 extract of the
8 x 272 table•~ 50 % of EMP have at least
one good solution (Xv2 < 2)

𝟀20

No rotation

Fast rotation
14•~ 70 % of C-rich EMP haveat least one good solution•~ 30 % of C-normal EMP haveat least one good solution

Systematic comparison : rotating massive stars vs. EMP stars
Choplin, Tominaga & Ishigaki (2019)•••272 EMP with -4 < [Fe/H] < -3
Analysis of light elements (C - Al)
Evolutionnary effects in EMP => corrections(e.g. dredge up)

Placco et al. (2014)

Match?

•

chi2 analysis••

20 M☉ , [Fe/H] = -3.8
8 initial rotations
Explo. with strong fallback

massive stars models

272 observed EMP stars>10 extract of the
8 x 272 table•~ 50 % of EMP have at least
one good solution (Xv2 < 2)

𝟀20

No rotation

Fast rotation
14•~ 70 % of C-rich EMP haveat least one good solution•~ 30 % of C-normal EMP haveat least one good solution

Models are adequate toreproduce most of
the C-rich EMP stars

Guessing the velocity of early massive sars from EMP stars
Choplin, Tominaga & Ishigaki (2019)

Velocity of 496 nearby
massive (OB) stars
Huang+2006

Velocity of the preferredmassive stars models(Mean velocity during MS)

15

Guessing the velocity of early massive sars from EMP stars
Choplin, Tominaga & Ishigaki (2019)

Velocity of 496 nearby
massive (OB) stars
Huang+2006

Velocity of the preferredmassive stars models(Mean velocity during MS)

Suggests numerous
fast rotating massive stars
in the early Universe

15

Guessing the velocity of early massive sars from EMP stars
Choplin, Tominaga & Ishigaki (2019)

Velocity of 496 nearby
massive (OB) stars
Huang+2006~ solar metallicity

Velocity of the preferredmassive stars models(Mean velocity during MS)very low metallicity

Suggests numerous
fast rotating massive stars
in the early Universe

15

Guessing the velocity of early massive sars from EMP stars
Choplin, Tominaga & Ishigaki (2019)

Velocity of 496 nearby
massive (OB) stars
Huang+2006~ solar metallicity

Velocity of the preferredmassive stars models(Mean velocity during MS)very low metallicity

Suggests numerous
fast rotating massive stars
in the early Universe
more fast rotators
than in thepresent-day Universe

15

Summary•

Metal-poor stars —> window on first massive stars—> mixing processes (mixing & fallback, rotation, shell mixing…)•

Rotation in low/zero metallicity massive stars => light / trans-Fe elements overproduced—> signature in some EMP(-s) stars

16Summary
Metal-poor stars —> window on first massive stars•—> mixing processes (mixing & fallback, rotation, shell mixing…)•

Rotation in low/zero metallicity massive stars => light / trans-Fe elements overproduced—> signature in some EMP(-s) stars•

20 M☉ with various rotations + strong fallback => adequate for ~70% of C-rich EMP•

Velocity distribution of best massive star models => numerous fast rotating
massive stars in the early Universe ?
—> Impact on reionization, light from high redshift galaxies, GRBs…?

16

Summary
Metal-poor stars —> window on first massive stars•—> mixing processes (mixing & fallback, rotation, shell mixing…)•

Rotation in low/zero metallicity massive stars => light / trans-Fe elements overproduced—> signature in some EMP(-s) stars•

20 M☉ with various rotations + strong fallback => adequate for ~70% of C-rich EMP•

Velocity distribution of best massive star models => numerous fast rotating
massive stars in the early Universe ?
—> Impact on reionization, light from high redshift galaxies, GRBs…?

Caution required because of :• Limiting assumptions• Uncertainties. Affect both models and abundances of EMP stars
Convection,• Rotation- Different prescriptions- Additional mixing? e.g. Eggenberger (2017)…
- …
• …
•

16

•

NLTE,

•

3D effects
e.g. Norris & Yong (2019)