Parent Volatiles in Comet 9P/Tempel 1: Before and After Impact

Abstract

We quantified eight parent volatiles (H 2 O, C 2 H 6 , HCN, CO, CH 3 OH, H 2 CO, C 2 H 2 , and CH 4 ) in the Jupiter-family comet Tempel 1 using high-dispersion infrared spectroscopy in the wavelength range 2.8 to 5.0 micrometers. The abundance ratio for ethane was significantly higher after impact, whereas those for methanol and hydrogen cyanide were unchanged. The abundance ratios in the ejecta are similar to those for most Oort cloud comets, but methanol and acetylene are lower in Tempel 1 by a factor of about 2. These results suggest that the volatile ices in Tempel 1 and in most Oort cloud comets originated in a common region of the protoplanetary disk.

Submillimeter Wave Astronomy Satellite observations of Comet 9P/Tempel 1 and Deep Impact

“…This is consistent with the temperatures derived from gaseous species observed using high-dispersion infrared spectroscopy (Mumma et al, 2005). Our results are not very sensitive to the assumed T kin in this range, however.…”

“…The water vapor production rate derived from a 3-day co-add of SWAS observations centered on the impact date is (5.2 ± 1.5) × 10 27 s −1 , consistent with the 3-day co-adds before and after the impact. This SWAS-measured water production rate is a factor of two lower than that derived by Mumma et al (2005) from their pre-impact observations of water hot-band emission in the near infrared, but is consistent with the water production rate measured by OH observations at UV wavelengths (Küppers et al, 2005;Schleicher et al, 2006). Published water production rates for 9P/Tempel 1 from other observations of submillimeter water lines were not yet available at the time of writing.…”

“…First results from the impact experiment have been reported by A' Hearn et al (2005), and an overview on the results from the Earth-based observing campaign is given by Meech et al (2005a). First results constraining the amount and composition of the dust in the ejecta are presented by Sugita et al (2005) and Harker et al (2005), while the volatiles released by the impact have been studied by Küppers et al (2005), Mumma et al (2005), and Keller et al (2005).…”

Ultraviolet spectroscopy of Comet 9P/Tempel 1 with Alice/Rosetta during the Deep Impact encounter

“…Both of these use Haser models similar to the one described above to interpret the observed photodissociation product, OH. Direct observations of water were made in both the infrared, using long-slit spectroscopy, by Mumma et al (2005), and in the sub-millimeter, by the Odin satellite, observing at 557 GHz (Biver et al 2005). They report water production rates of 10.4 × 10 27 molecules s −1 and (8.5 ± 1.5) × 10 27 molecules s −1 , respectively.…”

Comet 9P/Tempel 1: Interpretation with theDeep ImpactResults

“…(2) Near-infrared spectroscopic observations of volatiles excavated by the DI event revealed thermal processing of the layers below the dust mantle (Mumma et al 2005). (3) The existence of large compact dust in the preimpact T1 coma has been reported by many researchers (Sykes & Walker 1992;Farnham et al 2007;Reach, Kelley, & Sykes 2007).…”