The Far Ultraviolet Spectral Signatures of Formaldehyde and Carbon Dioxide in Comets

Details The Far Ultraviolet Spectral Signatures of Formaldehyde and Carbon Dioxide in Comets The Far Ultraviolet Spectral Signatures of Formaldehyde and Carbon Dioxide in Comets

2009-05-11

arxiv.org/abs/0905.1695v1

Astrophys.J.699:1104-1112,2009

Astronomy and Astrophysics

Astrophysics

Earth and Planetary Astrophysics

21 pages, 7 figures, accepted for publication in the Astrophysical Journal

Scientific paper

10.1088/0004-637X/699/2/1104

Observations of four comets made with the Far Ultraviolet Spectroscopic Explorer show the rotational envelope of the (0,0) band of the CO Hopfield-Birge system (C - X) at 1088 A to consist of both "cold" and "hot" components, the "cold" component accounting for ~75% of the flux and with a rotational temperature in the range 55-75 K. We identify the "hot" component as coming from the dissociation of CO2 into rotationally "hot" CO, with electron impact dissociation probably dominant over photodissociation near the nucleus. An additional weak, broad satellite band is seen centered near the position of the P(40) line that we attribute to CO fluorescence from a non-thermal high J rotational population produced by photodissociation of formaldehyde into CO and H2. This process also leaves the H2 preferentially populated in excited vibrational levels which are identified by fluorescent H2 lines in the spectrum excited by solar OVI 1031.9 and solar Lyman-alpha. The amount of H2 produced by H2CO dissociation is comparable to the amount produced by photodissociation of H2O. Electron impact excitation of CO, rather than resonance fluorescence, appears to be the primary source of the observed (B - X) (0,0) band at 1151 A.

Affiliated with

Also associated with

No associations

Rating

The Far Ultraviolet Spectral Signatures of Formaldehyde and Carbon Dioxide in Comets 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 The Far Ultraviolet Spectral Signatures of Formaldehyde and Carbon Dioxide in Comets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Far Ultraviolet Spectral Signatures of Formaldehyde and Carbon Dioxide in Comets will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-336210