Exploring organic chemistry in planet-forming zones

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Table 6

Observed molecular column density ratios relative to HCN as well as CH₃CN/NH₃ compared with chemical models and with cometary observations.

Obs/models	HNC	HC₃N	CH₃CN	NH₃	CH₃CN/NH₃

IRS 46	<0.3	<0.3	<210	<1.1	–
GV Tau	<0.7	<0.7	<140	<1.1	–
AS 205	–	–	–	<2.7¹^a	–
R = 3000²^b	<0.2	<0.1	<84	<0.4	–
R = 50 000³^b	<0.03	<0.08	<12	<0.08	–
Markwick et al. (2002) at 1 AU	1.0	1.0	1.0	1.0	1.0
Markwick et al. (2002) at 5 AU	1.0	1.0	1.0	1.1	0.9
Najita et al. (2011) ref	–	–	4.0	–	–
Najita et al. (2011) O/C = 1.0	–	–	0.01	–	–
Agúndez et al. (2008) 1 AU	0.01	–	–	6.0e-5	–
Agúndez et al. (2008) 3 AU	0.03	–	–	0.03	–
Mumma & Charnley (2011)	0.01–0.6	0.01–0.9	0.02–0.5	0.6–25	0.01–0.1
Garrod et al. (2008) M	–	–	–	890	7.5E-5

Notes.

^(a)

From 3 μm emission (Mandell et al. 2012).

^(b)

The R = 3000 and 50 000 values refer to the 3σ limits on the abundance ratios that can be obtained toward IRS 46 if observed at higher spectral resolution at a similar S/N.

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