We present interferometric detections of HCN in comets LINEAR ( C/2002 T7 ) and NEAT ( C/2001 Q4 ) with the Berkeley-Illinois-Maryland Association ( BIMA ) Array .
With a 25 { \farcs } 4 \times 20 { \farcs } 3 synthesized beam around Comet LINEAR and using a variable temperature and outflow velocity ( VTOV ) model , we found an HCN column density of < N _ { T } > = 6.4 \pm 2.1 \times 10 ^ { 12 } cm ^ { -2 } , and a production rate of Q ( HCN ) = 6.5 \pm 2.2 \times 10 ^ { 26 } s ^ { -1 } , giving a production rate ratio of HCN relative to H _ { 2 } O of \sim 3.3 \pm 1.1 \times 10 ^ { -3 } and relative to CN of \sim 4.6 \pm 1.5 .
With a 21 { \farcs } 3 \times 17 { \farcs } 5 synthesized beam around Comet NEAT and using a VTOV model , we found an HCN column density of < N _ { T } > = 8.5 \pm 4.5 \times 10 ^ { 11 } cm ^ { -2 } , and a production rate of Q ( HCN ) = 8.9 \pm 4.7 \times 10 ^ { 25 } s ^ { -1 } , giving a production rate ratio of HCN relative to H _ { 2 } O of \sim 7.4 \pm 3.9 \times 10 ^ { -4 } and relative to CN of \sim 0.3 \pm 0.2 .
For both comets , the production rates relative to H _ { 2 } O are similar to those found in previous comet observations .
For Comet LINEAR the production rate relative to CN is consistent with HCN being the primary parent species of CN , while for Comet NEAT it is too low for this to be the case .