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BIMA Array Detections of HCN in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4) D. N. Friedel (University of Illinois) Collaborators: A. Remijan (NASA GSFC)

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Presentation on theme: "BIMA Array Detections of HCN in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4) D. N. Friedel (University of Illinois) Collaborators: A. Remijan (NASA GSFC)"— Presentation transcript:

1 BIMA Array Detections of HCN in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4) D. N. Friedel (University of Illinois) Collaborators: A. Remijan (NASA GSFC) L. E. Snyder, H. R. Dickel, L.W. Looney (University of Illinois) M. F. A'Hearn (University of Maryland) I. De Pater, J. R. Forster, C. Kraybill, M. C. H. Wright (University of California, Berkeley) M. R. Hogerheijde (Leiden Observatory) P. Palmer (University of Chicago) G. A. Blake (Caltech) Adam Block/NOAO/AURA/NSF Svend and Carl Freytag/Adam Block/ NOAO/AURA/NSF 60 th International Symposium on Molecular Spectroscopy

2 Coordinates (J2000) and Synthesized Beams Observation Dates and Distances Spectral resolution: kHz chan -1 ( km s -1 chan -1 ) (1 AU ~ cm)Observations ~18”x15”  ~ 34:00  ~09:07 NEAT~26”x19”  ~ -09:30  ~01:40 LINEAR  ~ AU r h ~0.97 AU 2004 May NEAT  ~ AU r h ~ AU 2004 May LINEAR

3 Transitions

4 The VTOV Model Variable Temperature and Outflow Velocity From Combi, et al. 1999, ApJ, 512, 961 Haser model assumes constant temperature and outflow velocity This is not the case for higher resolution interferometric observations Models the comet as shells Models the comet as shells Temperature and outflow velocity assigned to each shell Temperature and outflow velocity assigned to each shell Model array response to each shell Model array response to each shell

5 NEATLINEAR 4.6(1.5)0.33(0.11)% 6.5(2.2)x (2.1)x10 12 LINEAR 0.3(0.2)0.07(0.04)% 8.9(4.7)x (4.5)x10 11 NEAT HCN / CN HCN / H 2 O Q p (s -1 ) N (cm -2 ) HCN J=1-0

6 3.8(0.8)% 7.5(1.7)x (0.3)x10 14 LINEAR 2.4(1.4)% 2.9(1.7)x (2.7)x10 13 NEAT CH 3 OH / H 2 O Q p (s -1 ) N (cm -2 ) CH 3 OH J=3 1,3 -4 0,4 A+ 0.04(0.01)% 8.7(3.0)x (0.6)x10 12 LINEAR <0.002% <2.1x10 24 <3.5x10 11 NEAT CS / H 2 O Q p (s -1 ) N (cm -2 ) CS J=2-1 NEAT LINEAR

7 Non-Detections Based on 1  rms noise level and single channel widthBased on 1  rms noise level and single channel width Continuum at 89 GHzContinuum at 89 GHz LINEAR<9 mJy beam -1 NEAT<1 mJy beam -1

8 Conclusions Used VTOV Model to calculate Q and NUsed VTOV Model to calculate Q and N LINEARLINEAR HCN/H 2 O similar to Hale-BoppHCN/H 2 O similar to Hale-Bopp CH 3 OH/H 2 O similar to Hale-BoppCH 3 OH/H 2 O similar to Hale-Bopp CS/H 2 O similar to Hyakutake and LINEAR (C/1999 B2)CS/H 2 O similar to Hyakutake and LINEAR (C/1999 B2) HNC/HCN <2.2%HNC/HCN <2.2% NEATNEAT HCN/H 2 O similar to HyakutakeHCN/H 2 O similar to Hyakutake CH 3 OH/H 2 O between Hale-Bopp and HyakutakeCH 3 OH/H 2 O between Hale-Bopp and Hyakutake

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