Table 3. Open in new tab Estimates of...

	Quantity	Potential habitable-zone terrestrial exoplanets (i.e. exo-Earths)^a	Pyrolite silicate Earth
Mantle	SiO₂	30.3 ± 2.6	50.7 ± 3.3	49.9 ± 4.9	40.5 ± 4.4	45.0
	CaO	2.50 ± 0.22	4.39 ± 0.34	3.85 ± 0.38	2.98 ± 0.36	3.55
	Na₂O	0.23 ± 0.02	0.43 ± 0.03	0.41 ± 0.04	0.41 ± 0.05	0.36
	MgO	29.2 ± 2.4	25.7 ± 3.6	43.3 ± 3.9	36.0 ± 4.0	37.8
	Al₂O₃	3.28 ± 0.31	–	–	4.01 ± 0.47	4.45
	FeO	31.3 ± 5.1	–	\|$1.53^{+8.35}_{1.53}$\|	13.9 ± 7.9	8.05
	NiO	1.71 ± 0.34	–	\|$0.15^{+0.40}_{-0.15}$\|	0.95 ± 0.51	0.25
	SO₃	1.25 ± 0.46	–	0.50 ± 0.48	0.90 ± 0.51	–
	CO₂	–	–	–	–	–
	Graphite	0.28 ± 0.05	0.38 ± 0.05	0.42 ± 0.06	0.30 ± 0.07	–
	Metals	–	18.4 ± 10.7	–	–	–
						McDonough (2014)^b
Core	Fe	85.7 ± 5.0	94.5 ± 0.6	94.1 ± 1.3	92.9 ± 1.9	92.33
	Ni	5.25 ± 0.73	5.49 ± 0.63	4.76 ± 0.65	5.69 ± 0.68	5.62
	S	9.07 ± 5.24	–	1.16 ± 1.14	\|$1.40^{+1.83}_{-1.40}$\|	2.05
Core mass fraction	\|$1.4^{+5.0}_{-1.4}$\|	35.3 ± 5.1	31.9 ± 5.9	19.6 ± 6.3	32.5 ± 0.3^c
(wt% planet)

Quantity

Potential habitable-zone terrestrial exoplanets (i.e. exo-Earths)^a

Pyrolite silicate Earth

(molar wt%)

K10-exoE

K20-exoE

K21-exoE

K100-exoE

McDonough & Sun (1995)

Mantle

SiO₂

30.3 ± 2.6

50.7 ± 3.3

49.9 ± 4.9

40.5 ± 4.4

45.0

CaO

2.50 ± 0.22

4.39 ± 0.34

3.85 ± 0.38

2.98 ± 0.36

3.55

Na₂O

0.23 ± 0.02

0.43 ± 0.03

0.41 ± 0.04

0.41 ± 0.05

0.36

MgO

29.2 ± 2.4

25.7 ± 3.6

43.3 ± 3.9

36.0 ± 4.0

37.8

Al₂O₃

3.28 ± 0.31

–

4.01 ± 0.47

4.45

FeO

31.3 ± 5.1

–

|$1.53^{+8.35}_{1.53}$|

13.9 ± 7.9

8.05

NiO

1.71 ± 0.34

–

|$0.15^{+0.40}_{-0.15}$|

0.95 ± 0.51

0.25

SO₃

1.25 ± 0.46

–

0.50 ± 0.48

0.90 ± 0.51

–

CO₂

–

Graphite

0.28 ± 0.05

0.38 ± 0.05

0.42 ± 0.06

0.30 ± 0.07

–

Metals

–

18.4 ± 10.7

–

McDonough (2014)^b

Core

85.7 ± 5.0

94.5 ± 0.6

94.1 ± 1.3

92.9 ± 1.9

92.33

5.25 ± 0.73

5.49 ± 0.63

4.76 ± 0.65

5.69 ± 0.68

5.62

9.07 ± 5.24

–

1.16 ± 1.14

|$1.40^{+1.83}_{-1.40}$|

2.05

Core mass fraction

|$1.4^{+5.0}_{-1.4}$|

35.3 ± 5.1

31.9 ± 5.9

19.6 ± 6.3

32.5 ± 0.3^c

(wt% planet)

	Quantity	Potential habitable-zone terrestrial exoplanets (i.e. exo-Earths)^a	Pyrolite silicate Earth
Mantle	SiO₂	30.3 ± 2.6	50.7 ± 3.3	49.9 ± 4.9	40.5 ± 4.4	45.0
	CaO	2.50 ± 0.22	4.39 ± 0.34	3.85 ± 0.38	2.98 ± 0.36	3.55
	Na₂O	0.23 ± 0.02	0.43 ± 0.03	0.41 ± 0.04	0.41 ± 0.05	0.36
	MgO	29.2 ± 2.4	25.7 ± 3.6	43.3 ± 3.9	36.0 ± 4.0	37.8
	Al₂O₃	3.28 ± 0.31	–	–	4.01 ± 0.47	4.45
	FeO	31.3 ± 5.1	–	\|$1.53^{+8.35}_{1.53}$\|	13.9 ± 7.9	8.05
	NiO	1.71 ± 0.34	–	\|$0.15^{+0.40}_{-0.15}$\|	0.95 ± 0.51	0.25
	SO₃	1.25 ± 0.46	–	0.50 ± 0.48	0.90 ± 0.51	–
	CO₂	–	–	–	–	–
	Graphite	0.28 ± 0.05	0.38 ± 0.05	0.42 ± 0.06	0.30 ± 0.07	–
	Metals	–	18.4 ± 10.7	–	–	–
						McDonough (2014)^b
Core	Fe	85.7 ± 5.0	94.5 ± 0.6	94.1 ± 1.3	92.9 ± 1.9	92.33
	Ni	5.25 ± 0.73	5.49 ± 0.63	4.76 ± 0.65	5.69 ± 0.68	5.62
	S	9.07 ± 5.24	–	1.16 ± 1.14	\|$1.40^{+1.83}_{-1.40}$\|	2.05
Core mass fraction	\|$1.4^{+5.0}_{-1.4}$\|	35.3 ± 5.1	31.9 ± 5.9	19.6 ± 6.3	32.5 ± 0.3^c
(wt% planet)

Table 3.

Open in new tab

Estimates of the mantle and core composition as well as core mass fraction of potential habitable-zone terrestrial exoplanets (i.e. exo-Earths) orbiting the studied host stars: Kepler-10 (K10), Kepler-20 (K20), Kepler-21 (K21), Kepler-100 (K100).

	Quantity	Potential habitable-zone terrestrial exoplanets (i.e. exo-Earths)^a				Pyrolite silicate Earth
	(molar wt%)	K10-exoE	K20-exoE	K21-exoE	K100-exoE	McDonough & Sun (1995)
Mantle	SiO₂	30.3 ± 2.6	50.7 ± 3.3	49.9 ± 4.9	40.5 ± 4.4	45.0
	CaO	2.50 ± 0.22	4.39 ± 0.34	3.85 ± 0.38	2.98 ± 0.36	3.55
	Na₂O	0.23 ± 0.02	0.43 ± 0.03	0.41 ± 0.04	0.41 ± 0.05	0.36
	MgO	29.2 ± 2.4	25.7 ± 3.6	43.3 ± 3.9	36.0 ± 4.0	37.8
	Al₂O₃	3.28 ± 0.31	–	–	4.01 ± 0.47	4.45
	FeO	31.3 ± 5.1	–	\|$1.53^{+8.35}_{1.53}$\|	13.9 ± 7.9	8.05
	NiO	1.71 ± 0.34	–	\|$0.15^{+0.40}_{-0.15}$\|	0.95 ± 0.51	0.25
	SO₃	1.25 ± 0.46	–	0.50 ± 0.48	0.90 ± 0.51	–
	CO₂	–	–	–	–	–
	Graphite	0.28 ± 0.05	0.38 ± 0.05	0.42 ± 0.06	0.30 ± 0.07	–
	Metals	–	18.4 ± 10.7	–	–	–
						McDonough (2014)^b
Core	Fe	85.7 ± 5.0	94.5 ± 0.6	94.1 ± 1.3	92.9 ± 1.9	92.33
	Ni	5.25 ± 0.73	5.49 ± 0.63	4.76 ± 0.65	5.69 ± 0.68	5.62
	S	9.07 ± 5.24	–	1.16 ± 1.14	\|$1.40^{+1.83}_{-1.40}$\|	2.05
Core mass fraction		\|$1.4^{+5.0}_{-1.4}$\|	35.3 ± 5.1	31.9 ± 5.9	19.6 ± 6.3	32.5 ± 0.3^c
(wt% planet)

	Quantity	Potential habitable-zone terrestrial exoplanets (i.e. exo-Earths)^a				Pyrolite silicate Earth
	(molar wt%)	K10-exoE	K20-exoE	K21-exoE	K100-exoE	McDonough & Sun (1995)
Mantle	SiO₂	30.3 ± 2.6	50.7 ± 3.3	49.9 ± 4.9	40.5 ± 4.4	45.0
	CaO	2.50 ± 0.22	4.39 ± 0.34	3.85 ± 0.38	2.98 ± 0.36	3.55
	Na₂O	0.23 ± 0.02	0.43 ± 0.03	0.41 ± 0.04	0.41 ± 0.05	0.36
	MgO	29.2 ± 2.4	25.7 ± 3.6	43.3 ± 3.9	36.0 ± 4.0	37.8
	Al₂O₃	3.28 ± 0.31	–	–	4.01 ± 0.47	4.45
	FeO	31.3 ± 5.1	–	\|$1.53^{+8.35}_{1.53}$\|	13.9 ± 7.9	8.05
	NiO	1.71 ± 0.34	–	\|$0.15^{+0.40}_{-0.15}$\|	0.95 ± 0.51	0.25
	SO₃	1.25 ± 0.46	–	0.50 ± 0.48	0.90 ± 0.51	–
	CO₂	–	–	–	–	–
	Graphite	0.28 ± 0.05	0.38 ± 0.05	0.42 ± 0.06	0.30 ± 0.07	–
	Metals	–	18.4 ± 10.7	–	–	–
						McDonough (2014)^b
Core	Fe	85.7 ± 5.0	94.5 ± 0.6	94.1 ± 1.3	92.9 ± 1.9	92.33
	Ni	5.25 ± 0.73	5.49 ± 0.63	4.76 ± 0.65	5.69 ± 0.68	5.62
	S	9.07 ± 5.24	–	1.16 ± 1.14	\|$1.40^{+1.83}_{-1.40}$\|	2.05
Core mass fraction		\|$1.4^{+5.0}_{-1.4}$\|	35.3 ± 5.1	31.9 ± 5.9	19.6 ± 6.3	32.5 ± 0.3^c
(wt% planet)

Notes.^aBulk elemental compositions of these exo-Earths are from Table 1.

^bMass fractions of the three elements in the core of McDonough (2014) have been renormalized under the assumption of only the three elements in the core.

^cRefers to Wang et al. (2018b), in which the core mass fraction is integrated from Earth’s radial density profiles.

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