Detection of Deuterium Emission from C/2001 Q4 (NEAT)

Details Detection of Deuterium Emission from C/2001 Q4 (NEAT) Detection of Deuterium Emission from C/2001 Q4 (NEAT)

Nov 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004dps....36.2301w&link_type=abstract

American Astronomical Society, DPS meeting #36, #23.01; Bulletin of the American Astronomical Society, Vol. 36, p.1120

Other

1

Scientific paper

We report the first detection of atomic deuterium (D) emission in a comet. On three different dates (2004 April 24.3, 26.9, and 28.8 UT), the D Lyman-α line at 1215.34 Å was clearly detected (S/N ˜6) during observations of comet C/2001 Q4 (NEAT) using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). During that time, the comet's heliocentric distance varied from 1.04 AU to 1.00 AU, the geocentric distance ranged from 0.54 AU to 0.39 AU, and the water production rate was ˜1.9 × 1029 s-1. The STIS echelle grating E140H was used with a 0.''2 × 6'' slit, which provides a velocity resolution of ˜5.5 km s-1 for a spatially uniform emission, to measure the D line simultaneously with the atomic hydrogen (H) Lyman-α line, both of which were cleanly separated from the terrestrial airglow H and D emissions. Since the observations were made with a relatively small aperture, detailed modeling is required to convert the observed D and H column densities into a cometary D/H ratio, which can then be compared to the deuterium abundance in other comets, in the earth's water, and in the interstellar medium. The derivation of the H production rate is relatively straightforward, but uncertainty in the photolysis pathways for HDO, the presumed primary source of D in the inner coma, and of the spatial distribution of D, make the derivation of an accurate D production rate problematic. We present our current best estimate for the D/H ratio in C/NEAT and discuss the prospects for improving the accuracy of that determination. We also briefly report on an HST search for D emission from C/2002 T7 (LINEAR), conducted during 2004 June 6-7 UT.

Affiliated with

Also associated with

No associations

Rating

Detection of Deuterium Emission from C/2001 Q4 (NEAT) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Detection of Deuterium Emission from C/2001 Q4 (NEAT), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detection of Deuterium Emission from C/2001 Q4 (NEAT) will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1013655