DPS 35th Meeting, 1-6 September 2003
Session 28. Comets II: Gas Species
Oral, Chairs: S. Wyckoff and N. Biver, Thursday, September 4, 2003, 4:30-5:40pm, DeAnza III

[Previous] | [Session 28] | [Next]

[28.01] A quantitative analysis of OH prompt emission in three comets: the 3046 cm-1 quadruplet and its use in determining cometary water production rates.

B. P. Bonev (Univ. of Toledo/NASA's GSFC), M. J. Mumma (NASA's GSFC), N. Dello Russo (Catholic Univ. of America/NASA's GSFC), E. L. Gibb (NAS-NRC/NASA's GSFC), M. A. DiSanti (NASA's GSFC), K. Magee-Sauer (Rowan Univ.)

Multiplets from OH in the 1-0 band were seen in prompt emission in several comets observed with NIRSPEC at the W. M. Keck Observatory (1, 2). These lines originate from vibrationally-excited rotationally-hot states of OH, produced by dissociative excitation of water. The various OH quadruplets span the L-band atmospheric window (2.9 - 3.7 \mum); here, we report results for the quadruplet falling near 3046 cm-1, including the effective g-factors in comets C/1999 H1 (Lee), C/2001 A2 (LINEAR), and C/2000 WM1 (LINEAR). The resulting spatial distribution of OH peaks at the nucleus and it traces that of the parent, H2O. (By contrast, OH fluorescent emission tracks the spatial distribution of OH itself.) OH prompt emission can provide an alternative way to determine water production rates in future comets, providing a convenient means for quantifying H2O simultaneously with several other parent species of "key" interest observed in the near-infrared. We discuss the significance of this approach, present our first quantitative results, and outline the direction of this work towards analysis of other OH multiplets.

This work was supported by a grant to M. J. Mumma (RTOP 344-32-30-07) from the Planetary Astronomy Program.

[1] M. J. Mumma et al., Ap. J. 546:1183-1193 (2001). [2] M. J. Mumma et al., Science 292:1334-1339 (2001).

[Previous] | [Session 28] | [Next]

Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.