Table 3.

Column densities and fractional abundances relative to H₂.

Source	n(H2) (cm−3)	N(H2) (cm−2)	N(HCCCHO) (cm−2)	N(c-C3H2O) (cm−2)	N(H2C3O) (cm−2)	f(HCCCHO)	f(c-C3H2O)	f(H2C3O)
TMC-1	(2 – 8) × 104	1.0 × 1022	8.0 × 1011	5.4 × 1010	< 2.1 × 1011	8.0 × 10−11	5.4 × 10−12	< 2.1 × 10−11
B1-b	1 × 105	1.5 × 1023	7.9 × 1011	8.9 × 1010	< 2.9 × 1011	5.3 × 10−12	5.9 × 10−13	< 1.9 × 10−12
L483	3.4 × 104	3.0 × 1022	6.0 × 1011	1.2 × 1011	< 2.3 × 1011	2.0 × 10−11	4.0 × 10−12	< 7.7 × 10−12
Lupus-1A	(1 – 10) × 105	1.5 × 1022	4.6 × 1011	7.4 × 1010	< 2.1 × 1011	3.1 × 10−11	4.9 × 10−12	< 1.4 × 10−11
L1495B	1.1 × 104	1.2 × 1022	3.3 × 1011	< 2.9 × 1010	< 1.4 × 1011	2.8 × 10−11	< 2.4 × 10−12	< 1.2 × 10−11
L1521F	1.1 × 106	1.35 × 1023	3.3 × 1011	< 4.2 × 1010	< 1.8 × 1011	2.4 × 10−12	< 3.1 × 10−13	< 1.3 × 10−12
Serpens South 1a	1.0 × 104	2.0 × 1022	1.3 × 1012	< 8.2 × 1010	< 2.9 × 1011	6.5 × 10−11	< 4.1 × 10−12	< 1.5 × 10−11

Column densities are derived adopting a rotational temperature of 10 K. Upper limits to the column densities are given at a 3σ confidence level.