Untitled

Bird, M. K.; Janardhan, P.; Wilson, Thomas L.; Huchtmeier, W. K.; Gensheimer, P. D.; Lemme, C.

doi:10.1023/a:1006246606131

Cited by 40 publications

(31 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recent reanalysis of the NH 2 spectra of many comets suggests a typical NH 3 abundance of 0.5% (Kawakita & Watanabe 2002, us-ing the comet database of Fink & Hicks 1996). This is less than the estimates of 1.0-1.8% from the radio detections of NH 3 in C/1995 O1 (Hale-Bopp) (Bird et al 1997(Bird et al , 2002Hirota et al 1999), but consistent with the revised estimate of 0.6% in C/1996 B2 (Hyakutake) (Bird et al 1999). The NH 2 data imply an ammonia abundance of 0.75% for comet 1P/Halley, i.e.…”

Section: Introductionmentioning

confidence: 92%

See 1 more Smart Citation

Recent searches for the radio lines of NH₃ in comets

Hatchell

Bird

Tak

et al. 2005

A&A

Self Cite

View full text Add to dashboard Cite

Abstract. Radio observations in the ammonia inversion lines of four comets, C/2001 A2 (LINEAR), 153P/Ikeya-Zhang, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), were performed at the Effelsberg 100-m Radio Telescope during their respective close approaches to Earth. None of the four lowest energy metastable lines (J, K = J), J = 1-4, could be detected in these comets. We derive the following 3σ upper bounds on the NH 3 production rate , and comparing to the corresponding water production rates, percentage NH 3 abundances relative to H 2 O: Q(NH 3 ) < 1.9 × 10

show abstract

Section: Introductionmentioning

confidence: 92%

“…The solid circle points with rms error bars for C/1995 O1 (Hale-Bopp) in Fig. 3 are derived from the measured (3, 3) line strengths (Bird et al 1997). The water production rate at perihelion, 1.0 × 10 31 s −1 , was taken from Colom et al (1999).…”

Section: Upper Limits On Nh 3 Column Densitiesmentioning

confidence: 99%

Recent searches for the radio lines of NH₃ in comets

Hatchell

Bird

Tak

et al. 2005

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…It has also been observed around the massive protostar GCS3 (Chiar et al 2000) and several other massive YSO such as W33A (Gibb et al 2000. Ammonia has also been detected extensively inside the solar system in cometary coma and on several moons (e.g., Kawakita et al 2006;Bird et al 1997;Moore et al 2007, and references therein).…”

Section: Introductionmentioning

confidence: 95%

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

Pilling

Duarte

Silveira³

et al. 2010

A&A

129

View full text Add to dashboard Cite

Deep inside dense molecular clouds and protostellar disks, interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions, molecular dissociation, and evaporation processes. We present experimental studies of the interaction of heavy, highly charged, and energetic ions (46 MeV 58 Ni 13+ ) with ammonia-containing ices H 2 O:NH 3 (1:0.5) and H 2 O:NH 3 :CO (1:0.6:0.4) in an attempt to simulate the physical chemistry induced by heavy-ion cosmic rays inside dense astrophysical environments. The measurements were performed inside a high vacuum chamber coupled to the IRRSUD (IR radiation SUD) beamline at the heavy-ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France. The gas samples were deposited onto a polished CsI substrate previously cooled to 13 K. In-situ analysis was performed by a Fourier transform infrared spectrometer (FTIR) at different fluences. The average values of the dissociation cross-section of water, ammonia, and carbon monoxide due to heavy-ion cosmic ray analogs are ∼2 × 10 −13 , 1.4 × 10 −13 , and 1.9 × 10 −13 cm 2 , respectively. In the presence of a typical heavy cosmic ray field, the estimated half life of the studied species is 2-3 × 10 6 years. The ice compaction (micropore collapse) produced by heavy cosmic rays seems to be at least 3 orders of magnitude higher than that produced by (0.8 MeV) protons. The infrared spectra of the irradiated ice samples exhibit lines of several new species including HNCO, N 2 O, OCN − , and NH + 4 . In the case of the irradiated H 2 O:NH 3 :CO ice, the infrared spectrum at room temperature contains five bands that are tentatively assigned to vibration modes of the zwitterionic glycine (NH + 3 CH 2 COO − ).

show abstract

“…They were then definitely detected in C/1996 B2 (Hyakutake) (Palmer et al 1996) and C/1995 O1 (Hale-Bopp) (Bird et al 1997;Hirota et al 1999) and tentatively detected in 153P/Ikeya-Zhang (Bird et al 2002;Hatchell et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Ammonia and other parent molecules in comet 10P/Tempel 2 fromHerschel/HIFI and ground-based radio observations

Biver

Crovisier

Bockelée‐Morvan

et al. 2012

A&A

View full text Add to dashboard Cite

The Jupiter-family comet 10P/Tempel 2 was observed during its 2010 return with the Herschel Space Observatory. We present here the observation of the J K (1 0 -0 0 ) transition of NH 3 at 572 GHz in this comet with the Heterodyne Instrument for the Far Infrared (HIFI) of Herschel. We also report on radio observations of other molecules (HCN, CH 3 OH, H 2 S and CS) obtained during the 1999 return of the comet with the CSO telescope and the JCMT, and during its 2010 return with the IRAM 30-m telescope. Molecular abundances relative to water are 0.09%, 1.8%, 0.4%, and 0.08% for HCN, CH 3 OH, H 2 S, and CS, respectively. An abundance of 0.5% for NH 3 is obtained, which is similar to the values measured in other comets. The hyperfine structure of the ammonia line is resolved for the first time in an astronomical source. Strong anisotropy in the outgassing is present in all observations from 1999 to 2010 and is modelled to derive the production rates.

show abstract

Untitled

Cited by 40 publications

References 8 publications

Recent searches for the radio lines of NH₃ in comets

Recent searches for the radio lines of NH₃ in comets

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

Ammonia and other parent molecules in comet 10P/Tempel 2 fromHerschel/HIFI and ground-based radio observations

Contact Info

Product

Resources

About

Untitled

Cited by 40 publications

References 8 publications

Recent searches for the radio lines of NH3 in comets

Recent searches for the radio lines of NH3 in comets

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

Ammonia and other parent molecules in comet 10P/Tempel 2 fromHerschel/HIFI and ground-based radio observations

Contact Info

Product

Resources

About

Recent searches for the radio lines of NH₃ in comets

Recent searches for the radio lines of NH₃ in comets