Standard abundances

The table below contains the standard set of elemental abundances, with respect to which all other abundances are defined in our database. The values vaguely represent the present day composition of the solar photosphere, although certain elements cannot be measured directly and must be inferred by other means.

All abundances are expressed following the standard astronomical convention. I.e., all values are expressed in dex and scaled to set the abundance of hydrogen to 12.00 exactly.

Shown in bold are the alpha elements, including all even atomic numbers between 8 (oxygen) and 22 (titanium) inclusive.

Symbol	Name	Atomic number	Atomic weight	Abundance	Error	Reference
H	Hydrogen	1	1.00797	12	0	[1]
He	Helium	2	4.0026	10.98	0	[2]
Li	Lithium	3	6.941	3.26	0.05	[4]
Be	Beryllium	4	9.01218	1.38	0.09	[3]
B	Boron	5	10.81	2.79	0.04	[4]
C	Carbon	6	12.011	8.5	0.06	[6]
N	Nitrogen	7	14.0067	7.86	0.12	[6]
O	Oxygen	8	15.9994	8.76	0.07	[6]
F	Fluorine	9	18.998403	4.56	0.3	[3]
Ne	Neon	10	20.179	8.02	0.09	[8]
Na	Sodium	11	22.98977	6.24	0.04	[3]
Mg	Magnesium	12	24.305	7.6	0.04	[3]
Al	Aluminium	13	26.98154	6.45	0.03	[3]
Si	Silicon	14	28.0855	7.51	0.03	[3]
P	Phosphorus	15	30.97376	5.46	0.04	[6]
S	Sulfur	16	32.06	7.16	0.05	[6]
Cl	Chlorine	17	35.453	5.5	0.3	[3]
Ar	Argon	18	39.948	6.4	0.13	[5]
K	Potassium	19	39.0983	5.11	0.09	[6]
Ca	Calcium	20	40.08	6.34	0.04	[3]
Sc	Scandium	21	44.9559	3.15	0.04	[3]
Ti	Titanium	22	47.9	4.95	0.05	[3]
V	Vanadium	23	50.9415	3.93	0.08	[3]
Cr	Chromium	24	51.996	5.64	0.04	[3]
Mn	Manganese	25	54.938	5.43	0.04	[3]
Fe	Iron	26	55.847	7.52	0.06	[6]
Co	Cobalt	27	58.9332	4.99	0.07	[3]
Ni	Nickel	28	58.7	6.22	0.04	[3]
Cu	Copper	29	63.546	4.19	0.04	[3]
Zn	Zinc	30	65.38	4.56	0.05	[3]
Ga	Gallium	31	69.72	3.04	0.09	[3]
Ge	Germanium	32	72.59	3.65	0.1	[3]
As	Arsenic	33	74.9216	2.3	0.04	[4]
Se	Selenium	34	78.96	3.34	0.03	[4]
Br	Bromine	35	79.904	2.54	0.06	[4]
Kr	Krypton	36	83.8	3.25	0.06	[5]
Rb	Rubidium	37	85.4678	2.36	0.03	[4]
Sr	Strontium	38	87.62	2.87	0.07	[3]
Y	Yttrium	39	88.9059	2.21	0.05	[3]
Zr	Zirconium	40	91.22	2.62	0.06	[7]
Nb	Niobium	41	92.9064	1.46	0.04	[3]
Mo	Molybdenum	42	95.94	1.88	0.08	[3]
Ru	Ruthenium	44	101.07	1.75	0.08	[3]
Rh	Rhodium	45	102.9055	1.06	0.04	[4]
Pd	Palladium	46	106.4	1.65	0.02	[4]
Ag	Silver	47	107.868	1.2	0.02	[4]
Cd	Cadmium	48	112.41	1.71	0.03	[4]
In	Indium	49	114.82	0.76	0.03	[4]
Sn	Tin	50	118.69	2.04	0.1	[3]
Sb	Antimony	51	121.75	1.01	0.06	[4]
Te	Tellurium	52	127.6	2.18	0.03	[4]
I	Iodine	53	126.9045	1.55	0.08	[4]
Xe	Xenon	54	131.3	2.24	0.06	[5]
Cs	Caesium	55	132.9054	1.08	0.02	[4]
Ba	Barium	56	137.33	2.18	0.09	[3]
La	Lanthanum	57	138.9055	1.1	0.04	[3]
Ce	Cerium	58	140.12	1.58	0.04	[3]
Pr	Praseodymium	59	140.9077	0.72	0.04	[3]
Nd	Neodymium	60	144.24	1.42	0.04	[3]
Sm	Samarium	62	150.4	0.96	0.04	[3]
Eu	Europium	63	151.96	0.52	0.04	[3]
Gd	Gadolinium	64	157.25	1.07	0.04	[3]
Tb	Terbium	65	158.9254	0.3	0.1	[3]
Dy	Dysprosium	66	162.5	1.1	0.04	[3]
Ho	Holmium	67	164.9304	0.48	0.11	[3]
Er	Erbium	68	167.26	0.92	0.05	[3]
Tm	Thulium	69	168.9342	0.1	0.04	[3]
Yb	Ytterbium	70	173.04	0.92	0.02	[4]
Lu	Lutetium	71	174.967	0.1	0.09	[3]
Hf	Hafnium	72	178.49	0.87	0.04	[6]
Ta	Tantalum	73	180.9479	-0.12	0.04	[4]
W	Tungsten	74	183.85	0.65	0.04	[4]
Re	Rhenium	75	186.207	0.26	0.04	[4]
Os	Osmium	76	190.2	1.36	0.19	[6]
Ir	Iridium	77	192.22	1.38	0.07	[3]
Pt	Platinum	78	195.09	1.62	0.03	[4]
Au	Gold	79	196.9665	0.8	0.04	[4]
Hg	Mercury	80	200.59	1.17	0.08	[4]
Tl	Thallium	81	204.37	0.77	0.03	[4]
Pb	Lead	82	207.2	2.04	0.03	[4]
Bi	Bismuth	83	208.9804	0.65	0.04	[4]
Th	Thorium	90	232.0381	0.08	0.03	[6]
U	Uranium	92	238.029	-0.54	0.03	[4]

References

[1] The hydrogen abundance is 12.00 by definition
[2] Helium abundance in a protostar using the standard solar model from Christensen-Dalsgaard 1998
[3] Present day spectroscopic photospheric abundances from Asplund+2009, table I
[4] Meteoritic abundances from Asplund+2009, table I
[5] Present day indirect photospheric abundances from Asplund+2009, table I (see section 3.6 for details)
[6] Present day spectroscopic photospheric abundances from Caffau+2011a, table V (using CO5BOLD 3D model of the solar atmosphere)
[7] Present day spectroscopic photospheric abundance of zirconium from Caffau+2011b
[8] Present day spectroscopic photospheric abundance of neon from Takeda+2010 based on a sample of B-stars