[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.