Large‐Aperture [O<scp>i</scp>] 6300 A Photometry of Comet Hale‐Bopp: Implications for the Photochemistry of OH

Morgenthaler, J. P.; Harris, Walter M.; Scherb, F.; Anderson, Christopher M.; Oliversen, R. J.; Doane, N. E.; Combi, M. R.; Marconi, Maximus L.; Smyth, W. H.

doi:10.1086/323773

Cited by 64 publications

(83 citation statements)

References 45 publications

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“…The first one is that, because the lifetime of the 1 D state is ∼110 s, much shorter than the corresponding lifetime of water molecule (∼8 × 10 4 s) at 1 AU, the red emission lines are a good tracer of water molecule distribution in the cometary coma. The second and more important reason is that, if water is the main producer of these lines, then from the O column density the H 2 O production rate can be deduced (see, for example, Morgenthaler et al 2001Morgenthaler et al , 2004.…”

Section: Introductionmentioning

confidence: 99%

“…One or more of these lines were detected many times (Fink & Johnson 1984;Magee-Sauer et al 1990;Schultz et al 1993;Morrison et al 1997;Cochran 1984;Cochran & Cochran 2001;Zhang et al 2001;Morgenthaler et al 2001, reporting the more recent papers), but their unambiguous detection, especially the line at 5577 Å is a non-trivial task. Firstly, high spectral resolution is necessary to discriminate the three lines from the usually strong telluric O emission lines.…”

Section: Introductionmentioning

confidence: 99%

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O($^{\mathsf 1}$S) and O($^{\mathsf 1}$D) emission lines in the spectrum of 153P/2002 C1 (Ikeya-Zhang)

Capria¹,

Cremonese

Bhardwaj

et al. 2005

A&A

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High resolution spectroscopy observation of comet 153P/2002 C1 Ikeya-Zhang was performed on April 20, 2002 with the echelle spectrograph SARG on the 3.5 m Telescopio Nazionale Galileo in La Palma. The atomic O emission lines at 5577, 6360 and 6363 Å are clearly visible in the spectrum. We determined the intensity ratio of the green line to the sum of the red lines. In order to verify the hypothesis that water is the main parent species of these emissions, the result was compared with the value obtained from a coupled chemistry-transport model. The measured value for the green to red ratio, 0.12 ± 0.1, agrees quite well with the value obtained from the model. This led us to conclude that during the observation water was the parent species of atomic O lines.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

O($^{\mathsf 1}$S) and O($^{\mathsf 1}$D) emission lines in the spectrum of 153P/2002 C1 (Ikeya-Zhang)

Capria¹,

Cremonese

Bhardwaj

et al. 2005

A&A

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“…An exception is the H 2 O hot-band emission at infrared wavelengths (e.g., Bockelée-Morvan & Crovisier 1989), which have been used to derive water production rates in several comets (Dello Russo et al 2002a, 2002bMumma et al 2003 and references therein). Traditionally, however, most of the studies of the water production rate have been based on more easily observable secondary tracers, such as the water photodissociation products OH, H, and O ( Feldman et al 2004;Mumma et al 2001b;Morgenthaler et al 2001 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Submillimeter Wave Astronomy SatelliteMonitoring of the Postperihelion Water Production Rate of Comet C/1999 T1 (McNaught‐Hartley)

Bensch¹,

Bergin²,

Bockelée‐Morvan³

et al. 2004

ApJ

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We present observations of the pure rotational transition 1 10 ! 1 01 of ortho-H 2 O vapor at 556.936 GHz made with the Submillimeter Wave Astronomy Satellite (SWAS ) for comet C/1999 T1 (McNaught-Hartley). The emission was monitored during the postperihelion phase from ( UT) 2001 February 2.00 to 11.07 and February 23.01 to April 5.95 for a Sun-comet distance, r h , ranging from 1.41 to 2.05 AU. The water production rate, Q H 2 O , derived from the observations depends on the assumptions regarding the electron abundance in the coma. We obtain Q H 2 O $ 4 ; 10 28 s À1 for the observations made in the first week of February (r h $1:4 AU ) using a model in which the electron abundance has been normalized to the in situ measurements obtained in 1P/Halley. The value of Q H 2 O decreases for larger r h , and we derive $1:5 ; 10 28 s À1 for the observations made at r h $ 2 AU in the last week of 2001 March. The inferred water production rate is larger by $40% for a radiative transfer model with the electron abundance reduced by 80% because of the reduced excitation of water by electron collisions in this model. A comparison to literature data suggests that the SWAS results derived with the smaller electron abundance are in better agreement with independent measurements of Q H 2 O obtained from observations of H 2 O photodissociation products. A 2 fit to the variation of Q H 2 O with the heliocentric distance gives a power-law index of À3:0 AE 0:5 (statistical) AE0.1 (systematic).

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“…Measuring atomic oxygen visible emission line intensities is an important diagnostic tool in estimating the water production rate as well as to understand the spatial distribution of H 2 O in the cometary coma (Delsemme & Combi 1976, 1979Fink & Johnson 1984;Schultz et al 1992;Morgenthaler et al 2001;Furusho et al 2006). Decock et al (2015) analyzed several ESOʼs VLT observed high-resolution green-and red-doublet emission line spectra on various comets.…”

Section: Derivation Of Co and Co 2 Volume Mixing Ratios Relativementioning

confidence: 99%

Prediction of Forbidden Ultraviolet and Visible Emissions in Comet 67p/Churyumov–gerasimenko

Raghuram

Bhardwaj

Galand

2016

ApJ

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Remote observation of spectroscopic emissions is a potential tool for the identification and quantification of various species in comets. The CO Cameron band (to trace CO 2 ) and atomic oxygen emissions (to trace H 2 O and/ or CO 2 , CO) have been used to probe neutral composition in the cometary coma. Using a coupled-chemistryemission model, various excitation processes controlling the CO Cameron band and different atomic oxygen and atomic carbon emissions have been modeled in comet 67P/Churyumov-Gerasimenko at 1.29 AU (perihelion) and at 3 AU heliocentric distances, which is being explored by ESAʼs Rosetta mission. The intensities of the CO Cameron band, atomic oxygen, and atomic carbon emission lines as a function of projected distance are calculated for different CO and CO 2 volume mixing ratios relative to water. Contributions of different excitation processes controlling these emissions are quantified. We assess how CO 2 and/or CO volume mixing ratios with respect to H 2 O can be derived based on the observed intensities of the CO Cameron band, atomic oxygen, and atomic carbon emission lines. The results presented in this work serve as baseline calculations to understand the behavior of low out-gassing cometary coma and compare them with the higher gas production rate cases (e.g., comet Halley). Quantitative analysis of different excitation processes governing the spectroscopic emissions is essential to study the chemistry of inner coma and to derive neutral gas composition.

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Large‐Aperture [Oi] 6300 A Photometry of Comet Hale‐Bopp: Implications for the Photochemistry of OH

Cited by 64 publications

References 45 publications

O($^{\mathsf 1}$S) and O($^{\mathsf 1}$D) emission lines in the spectrum of 153P/2002 C1 (Ikeya-Zhang)

O($^{\mathsf 1}$S) and O($^{\mathsf 1}$D) emission lines in the spectrum of 153P/2002 C1 (Ikeya-Zhang)

Submillimeter Wave Astronomy SatelliteMonitoring of the Postperihelion Water Production Rate of Comet C/1999 T1 (McNaught‐Hartley)

Prediction of Forbidden Ultraviolet and Visible Emissions in Comet 67p/Churyumov–gerasimenko

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