3.1.1. Abundance: standard abundances

3.1.1.1. Overview

For the plasma models, a default set of abundances is used. All abundances are calculated relative to those standard values. The current default abundance set are the proto-Solar abundances of Lodders et al. (2009). Note that in older versions of SPEX, Anders & Grevesse (1989) was the default. In particular, we recommend to use the proto-Solar (= Solar system) abundances for most applications, as the Solar photospheric abundance has been affected by nucleosynthesis (burning of H to He) and settlement in the Sun during its lifetime. The following abundances (see the Table below) can be used in SPEX:

Standard abundance sets

Abbrevation	Reference
reset	default Lodders et al. (2009)
ag	Anders & Grevesse (1989)
allen	Allen (1973)
ra	Ross & Aller (1976)
grevesse	Grevesse et al. (1992)
gs	Grevesse & Sauval (1998)
lodders	Lodders proto-Solar Lodders
solar	Lodders Solar photospheric Lodders

For the case of Grevesse & Sauval (1998) we adopted their meteoritic values (in general more accurate than the photospheric values, but in most cases consistent), except for He (slightly enhanced in the solar photosphere due to element migration at the bottom of the convection zone), C, N and O (largely escaped from meteorites) Ne and Ar (noble gases).

In the table below, we show the values of the standard abundances. They are expressed in logarithmic units, with hydrogen by definition 12.0.

Abundances for the standard sets

Z	elem	Default	AG	Allen	RA	Grevesse	GS	Lodders	solar
1	H	12.000	12.00	12.00	12.00	12.00	12.00	12.00	12.00
2	He	10.987	10.99	10.93	10.80	10.97	10.99	10.98	10.90
3	Li	3.331	1.16	0.70	1.00	1.16	3.31	3.35	3.28
4	Be	1.373	1.15	1.10	1.15	1.15	1.42	1.48	1.41
5	B	2.860	2.6	<3.0	2.11	2.6	2.79	2.85	2.78
6	C	8.443	8.56	8.52	8.62	8.55	8.52	8.46	8.39
7	N	7.912	8.05	7.96	7.94	7.97	7.92	7.90	7.83
8	O	8.782	8.93	8.82	8.84	8.87	8.83	8.76	8.69
9	F	4.491	4.56	4.60	4.56	4.56	4.48	4.53	4.46
10	Ne	8.103	8.09	7.92	7.47	8.08	8.08	7.95	7.87
11	Na	6.347	6.33	6.25	6.28	6.33	6.32	6.37	6.30
12	Mg	7.599	7.58	7.42	7.59	7.58	7.58	7.62	7.55
13	Al	6.513	6.47	6.39	6.52	6.47	6.49	6.54	6.46
14	Si	7.586	7.55	7.52	7.65	7.55	7.56	7.61	7.54
15	P	5.505	5.45	5.52	5.50	5.45	5.56	5.54	5.46
16	S	7.210	7.21	7.20	7.20	7.21	7.20	7.26	7.19
17	Cl	5.299	5.5	5.60	5.50	5.5	5.28	5.33	5.26
18	Ar	6.553	6.56	6.90	6.01	6.52	6.40	6.62	6.55
19	K	5.161	5.12	4.95	5.16	5.12	5.13	5.18	5.11
20	Ca	6.367	6.36	6.30	6.35	6.36	6.35	6.41	6.34
21	Sc	3.123	1.10	1.22	1.04	3.20	3.10	3.15	3.07
22	Ti	4.979	4.99	5.13	5.05	5.02	4.94	5.00	4.92
23	V	4.042	4.00	4.40	4.02	4.00	4.02	4.07	4.00
24	Cr	5.703	5.67	5.85	5.71	5.67	5.69	5.72	5.65
25	Mn	5.551	5.39	5.40	5.42	5.39	5.53	5.58	5.50
26	Fe	7.514	7.67	7.60	7.50	7.51	7.50	7.54	7.47
27	Co	4.957	4.92	5.10	4.90	4.92	4.91	4.98	4.91
28	Ni	6.276	6.25	6.30	6.28	6.25	6.25	6.29	6.22
29	Cu	4.319	4.21	4.50	4.06	4.21	4.29	4.34	4.26
30	Zn	4.700	4.60	4.20	4.45	4.60	4.67	4.70	4.63

Warning

For Allen (1973) the value for boron is just an upper limit.

The current active solar abundance table can be shown using the command abundance show.

3.1.1.2. Syntax

The following syntax rules apply:

abundance #a : Set the standard abundances to the values of reference #a in the table above.

abundance show : Show the currently active abundance table.

3.1.1.3. Examples

abundance gs : change the standard abundances to the set of Grevesse & Sauval (1998)

abundance reset : reset the abundances to the standard set

abundance show : show the currently active abundance table