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Title: Ground-based multiwavelength observations of comet 103P/Hartley 2

The Jupiter-family comet 103P/Hartley 2 (103P) was the target of the NASA EPOXI mission. In support of this mission, we conducted observations from radio to submillimeter wavelengths of comet 103P in the three weeks preceding the spacecraft rendezvous on UT 2010 November 4.58. This time period included the passage at perihelion and the closest approach of the comet to the Earth. Here, we report detections of HCN, H{sub 2}CO, CS, and OH and upper limits for HNC and DCN toward 103P using the Arizona Radio Observatory Kitt Peak 12 m telescope (ARO 12 m) and submillimeter telescope (SMT), the James Clerk Maxwell Telescope (JCMT), and the Green Bank Telescope (GBT). The water production rate, Q{sub H{sub 2O}} = (0.67-1.07) × 10{sup 28} s{sup –1}, was determined from the GBT OH data. From the average abundance ratios of HCN and H{sub 2}CO relative to water (0.13 ± 0.03% and 0.14 ± 0.03%, respectively), we conclude that H{sub 2}CO is depleted and HCN is normal with respect to typically observed cometary mixing ratios. However, the abundance ratio of HCN with water shows a large diversity with time. Using the JCMT data, we measured an upper limit for the DCN/HCN ratio <0.01. Consecutivemore » observations of ortho-H{sub 2}CO and para-H{sub 2}CO on November 2 (from data obtained at the JCMT) allowed us to derive an ortho:para ratio (OPR) of ≈2.12 ± 0.59 (1σ), corresponding to T {sub spin} > 8 K (2σ).« less
Authors:
; ;  [1] ; ;  [2] ;  [3] ;  [4] ; ;  [5]
  1. Catholic University of America, Physics Department, 620 Michigan Avenue NE, Washington, DC (United States)
  2. Goddard Center for Astrobiology, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)
  3. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
  4. Joint Astronomy Centre, 660 North A'ohoku Place University Park, Hilo, HI 96720 (United States)
  5. National Taiwan Normal University, 88 Sec. 4 Ting-Chou Road, Taipei 116, Taiwan (China)
Publication Date:
OSTI Identifier:
22370524
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMETS; DETECTION; ELEMENT ABUNDANCE; HYDROCYANIC ACID; NASA; TELESCOPES; WAVELENGTHS