**Table 5:** N₂H⁺ and N₂D⁺ column densities.
Source	N(N₂H⁺)	N(N₂D⁺)	N(N₂D⁺)/N(N₂H⁺)
	[cm^-2]	[cm^-2]
L 1448 IRS 2	$3.1 \times 10^{13}$	$1.3 \times 10^{12}$	0.042 $\pm$ 0.014
L 1448 IRS 3	$4.8 \times 10^{13}$	$3.9 \times 10^{12}$	0.081 $\pm$ 0.010
L 1448 C	$2.4 \times 10^{13}$	$2.5 \times 10^{12}$	0.104 $\pm$ 0.017
L 1455 A1	$9.2 \times 10^{12}$	$6.3 \times 10^{11}$	0.068 $\pm$ 0.043
L 1455 A2	$1.4 \times 10^{13}$	$9.6 \times 10^{11}$	0.069 $\pm$ 0.029
Per 4 S	$7.9 \times 10^{12}$	$1.4 \times 10^{12}$	0.177 $\pm$ 0.032
Per 4 N	$7.1 \times 10^{12}$	$7.8 \times 10^{11}$	0.110 $\pm$ 0.057
Per 5	$1.2 \times 10^{13}$	$1.0 \times 10^{12}$	0.083 $\pm$ 0.033
Per 6	$6.1 \times 10^{12}$	< $1.8\times 10^{11}$	<0.029
IRAS 03282	$1.6 \times 10^{13}$	$3.5 \times 10^{12}$	0.219 $\pm$ 0.026
Barnard 1-B	$4.5 \times 10^{13}$	$8.1 \times 10^{12}$	0.180 $\pm$ 0.009
HH 211	$1.7\times 10^{13}$	$4.6\times 10^{12}$	0.271 $\pm$ 0.024
Barnard 5 IRS 1	1. $6\times 10^{13}$	$5.4\times 10^{11}$	0.034 $\pm$ 0.025
L 1527	$7.2 \times 10^{12}$	< $2.5\times 10^{11}$	<0.034
L 483	$3.3 \times 10^{13}$	$1.9 \times 10^{12}$	0.057 $\pm$ 0.012
SMM 5	$2.9 \times 10^{13}$	$2.3 \times 10^{12}$	0.079 $\pm$ 0.019
L 723	$8.8 \times 10^{12}$	$4.0 \times 10^{11}$	0.045 $\pm$ 0.040
L 673 A	$1.3\times 10^{13}$	$4.3 \times 10^{11}$	0.033 $\pm$ 0.031
B 335	$1.4 \times 10^{13}$	$6.0 \times 10^{11}$	0.043 $\pm$ 0.029
L 1157	$1.1 \times 10^{13}$	$5.0 \times 10^{11}$	0.045 $\pm$ 0.036

Estimated errors on the column densities are about 15% and 20%
for N₂H⁺ and N₂D⁺, respectively.

Source LaTeX | All tables | In the text