Table 3.13 Terrestrial isotopic ratios from standard references (Hoppe et al. 2018) and some
comparison values from comet observations of different types. The table is intended to be illustrative and not comprehensive
Isotopic
ratio
Reference Value
Cometary values
Source
D/H
VSMOW 0.00015576 0.000308 + 0.000038/
À0.000053 (Balsiger et al.
1995)
Giotto H 2 O 1P/Halley
0.000161 Æ 0.000024 (Hartogh
et al. 2011)
Herschel H 2 O
103P/Hartley 2
0.00065 Æ 0.00016 (Biver et al.
2016)
IRAM/Odin H 2 O
C/2012 F6 (Lemmon)
0.00014 Æ 0.00004 (Biver et al.
2016)
IRAM/Odin H 2 O C/
2014 Q2 (Lovejoy)
0.00053 Æ 0.00007 (Altwegg
et al. 2015)
Rosetta H 2 O 67P
13
C/
12
C PDB
0.0112372
0.0110 (Manfroid et al. 2009)
Ground-based CN
average many comets
0.0092 Æ 0.0013 (Biver et al.
2016)
IRAM/Odin HCN C/
2014 Q2 (Lovejoy)
0.0119 Æ 0.0006 (Hässig et al.
2017)
Rosetta CO 2 67P
0.0116 Æ 0.0012 (Rubin et al.
2017)
Rosetta CO 67P
15
N/
14
N Air
0.0036765
0.00677 (Manfroid et al. 2009) Ground-based CN
average many comets
0.00737 Æ 0.00031 (Shinnaka
et al. 2016)
Ground-based NH 3
average many comets
17
O/
16
O VSMOW 0.0003799
0.00037 Æ 0.00009 (Altwegg
et al. 2015)
Rosetta H 2 O 67P
18
O/
16
O VSMOW 0.0020052
0.0019 (Balsiger et al. 1995)
Giotto H 2 O 1P/Halley
0.00200 Æ 0.00010 (Biver et al.
2016)
IRAM/Odin H2O C/
2014 Q2 (Lovejoy)
0.00202 Æ 0.003 (Hässig et al.
2017)
Rosetta CO 2 67P
0.0018 Æ 0.0002 (Altwegg et
al. 2015)
Rosetta H 2 O 67P
29
Si/
28 Si NIST
NBS 28
0.050804
0.0434 Æ 0.0050 (Rubin et al.
2017)
Rosetta Si 67P
30
Si/
28 Si NIST
NBS 28
0.033532
0.0263 Æ 0.0038 (Rubin et al.
2017)
Rosetta Si 67P
33
S/
32
S
VCDT
0.0078773
0.00658 (Calmonte et al. 2017) Rosetta H 2 S, OCS, CS 2
weight mean, 67P
34
S/
32
S
VCDT
0.0441626
0.043 (Altwegg 1996)
Giotto S
+ 1P/Halley
0.0420 (Calmonte et al. 2017)
Rosetta H 2 S, OCS, CS 2
weight mean, 67P
0.0463 Æ 0.0057 (Paquette et
al. 2017)
Rosetta/COSIMA S
67P
278
3 Gas Emissions Near the Nucleus