References of "Hutsemekers, Damien"
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See detailHigh-dispersion infrared spectroscopic observations of comet 8P/Tuttle with VLT/CRIRES
Kobayashi, H.; Bockelée-Morvan, D.; Kawakita, H. et al

in Astronomy and Astrophysics (2010), 509

We report on the composition of the Halley-family comet (HFC) 8P/Tuttle investigated with high-dispersion near-infrared spectroscopic observations. The observations were carried out at the ESO VLT (Very ... [more ▼]

We report on the composition of the Halley-family comet (HFC) 8P/Tuttle investigated with high-dispersion near-infrared spectroscopic observations. The observations were carried out at the ESO VLT (Very Large Telescope) with the CRIRES instrument as part of a multi-wavelength observation campaign of 8P/Tuttle performed in late January and early February 2008. Radar observations suggested that 8P/Tuttle is a contact binary, and it was proposed that these components might be heterogeneous in chemistry. We determined mixing ratios of organic volatiles with respect to H[SUB]2[/SUB]O and found that mixing ratios were consistent with previous near infrared spectroscopic observations obtained in late December 2007 and in late January 2008. It has been suggested that because 8P/Tuttle is a contact binary, it might be chemically heterogeneous. However, we find no evidence for chemical heterogeneity within the nucleus of 8P/Tuttle. We also compared the mixing ratios of organic molecules in 8P/Tuttle with those of both other HFCs and long period comets (LPCs) and found that HCN, C[SUB]2[/SUB]H[SUB]2[/SUB], and C[SUB]2[/SUB]H[SUB]6[/SUB] are depleted whereas CH[SUB]4[/SUB] and CH[SUB]3[/SUB]OH have normal abundances. This may indicate that 8P/Tuttle was formed in a different region of the early solar nebula than other HFCs and LPCs. We estimated the conversion efficiency from C[SUB]2[/SUB]H[SUB]2[/SUB] to C[SUB]2[/SUB]H[SUB]6[/SUB] by hydrogen addition reactions on cold grains by employing the C[SUB]2[/SUB]H[SUB]6[/SUB]/(C[SUB]2[/SUB]H[SUB]6[/SUB]+C[SUB]2[/SUB]H[SUB]2[/SUB]) ratio. The C[SUB]2[/SUB]H[SUB]6[/SUB]/(C[SUB]2[/SUB]H[SUB]6[/SUB]+C[SUB]2[/SUB]H[SUB]2[/SUB]) ratio in 8P/Tuttle is consistent with the ratios found in other HFCs and LPCs within the error bars. We also discuss the source of C[SUB]2[/SUB] and CN based on our observations and conclude that the abundances of C[SUB]2[/SUB]H[SUB]2[/SUB] and C[SUB]2[/SUB]H[SUB]6[/SUB] are insufficient to explain the C[SUB]2[/SUB] abundances in comet 8P/Tuttle and that the abundance of HCN is insufficient to explain the CN abundances in the comet, so at least one additional parent is needed for each species, as pointed out in previous study. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Prog. 080.C-0615 and 280.C-5053).We regret to note the death of Dr. J. -M. Zucconi in 2009 May. [less ▲]

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See detailObservations of nebulae ejected by massive stars with PACS
Vamvatira-Nakou, Chloi ULg; Royer, P.; Hutsemekers, Damien ULg et al

Poster (2010)

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See detailLarge-scale coherent orientations of quasar polarisation vectors: interpretation in terms of axion-like particles
Payez, Alexandre ULg; Hutsemekers, Damien ULg; Cudell, Jean-René ULg

in AIP Conference Proceedings (2010), 1274,

The observation of redshift-dependent coherent orientations of quasar polarisation vectors over cosmological distances in some regions of the sky is reviewed. Based on a good-quality sample of 355 ... [more ▼]

The observation of redshift-dependent coherent orientations of quasar polarisation vectors over cosmological distances in some regions of the sky is reviewed. Based on a good-quality sample of 355 measured quasars, this observation seems to infer the existence of a new effect acting on light propagation on such huge distances. A solution in terms of nearly massless axion-like particles has been proposed in the literature and its current status is discussed. [less ▲]

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See detailFirst results of the HssO key programme
Hartogh, Paul; Crovisier, Jacques; Lellouch et al

in 38th COSPAR Scientific Assembly (2010)

The HssO (Herschel solar system Observations) program aims at determining the distribution, the evolution and the origin of water in Mars, the Outer Planets, Titan, Enceladus and comets, using the three ... [more ▼]

The HssO (Herschel solar system Observations) program aims at determining the distribution, the evolution and the origin of water in Mars, the Outer Planets, Titan, Enceladus and comets, using the three Herschel instruments HIFI, PACS and SPIRE. It addresses the broad topic of water and its isotopologues in planetary and cometary atmospheres. The nature of cometary activity and the thermodynamics of cometary comae will be investigated by studying water excitation in a sample of comets. The D/H ratio, the key parameter for constraining the origin and evolution of Solar System materials, will be measured for the first time in a Jupiter family comet. A comparison with existing and new measurements of D/H in Oort cloud comets will constrain the composition of pre-solar cometary grains and possibly the dynamics of the protosolar nebula. New measurements of D/H in Giant Planets, similarly constraining the composition of proto-planetary ices, will be obtained. The D/H and other isotopic ratios, diagnostics of the evolution of Mars atmosphere, will be accurately measured in H2O and CO. The role of water vapour in the atmospheric chemistry of Mars will be studied by monitoring vertical profiles of H2O and HDO and by searching for several other species (including CO and H2O isotopologues). A detailed study of the source of water in the upper atmosphere of the Giant Planets and Titan will be performed. By monitoring the water abundance, vertical profile, and input fluxes in the various objects, and when possible with the help of mapping observations, we will discriminate between the possible sources of water in the Outer Planets (interplanetary dust particles, cometary impacts, and local sources). First results on comets, Mars and the outer planets will be presented. [less ▲]

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See detailOn the circular polarisation of light from axion-photon mixing
Payez, Alexandre ULg; Cudell, Jean-René ULg; Hutsemekers, Damien ULg

in Alimi, Jean-Michel; Füzfa, André (Eds.) INVISIBLE UNIVERSE: Proceedings of the Conference. AIP Conference Proceedings 1241. (2010)

From the analysis of measurements of the linear polarisation of visible light coming from quasars, the existence of large-scale coherent orientations of quasar polarisation vectors in some regions of the ... [more ▼]

From the analysis of measurements of the linear polarisation of visible light coming from quasars, the existence of large-scale coherent orientations of quasar polarisation vectors in some regions of the sky has been reported. Here, we show that this can be explained by the mixing of the incoming photons with nearly massless pseudoscalar (axion-like) particles in extragalactic magnetic fields. We present a new treatment in terms of wave packets and discuss its implications for the circular polarisation. [less ▲]

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See detailAxion-like particles and circular polarisation of active galactic nuclei
Payez, Alexandre ULg; Cudell, Jean-René ULg; Hutsemekers, Damien ULg

in Jaeckel, Joerg; Lindner, Axel; Redondo, Javier (Eds.) Proceedings of the 5th Patras Workshop on Axions, WIMPs and WISPs PATRAS 2009 (2010)

The measurements of the linear polarisation of visible light from quasars give strong evidence for large-scale coherent orientations of their polarisation vectors in some regions of the sky. We show that ... [more ▼]

The measurements of the linear polarisation of visible light from quasars give strong evidence for large-scale coherent orientations of their polarisation vectors in some regions of the sky. We show that these observations can be explained by the mixing of the photons with very light pseudoscalar (axion-like) particles in extragalactic magnetic fields during their propagation. We present a new treatment in terms of wave packets and discuss the circular polarisation. [less ▲]

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See detailA study of the distant activity of comet C/2006 W3 (Christensen) using Herschel and ground-based radio telescopes
Bockelée-Morvan, D.; Hartogh, P.; Crovisier, J. et al

Poster (2010)

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See detailNew constraints on the delivery of cometary water and nitrogen to Earth from the 15N/14N isotopic ratio
Hutsemekers, Damien ULg; Manfroid, Jean ULg; Jehin, Emmanuel ULg et al

in Icarus: International Journal of Solar System Studies (2009), 204

New independent constraints on the amount of water delivered to Earth by comets are derived using the [SUP]15[/SUP]N/[SUP]14[/SUP]N isotopic ratio, measured to be roughly twice as high in cometary CN and ... [more ▼]

New independent constraints on the amount of water delivered to Earth by comets are derived using the [SUP]15[/SUP]N/[SUP]14[/SUP]N isotopic ratio, measured to be roughly twice as high in cometary CN and HCN as in the present Earth. Under reasonable assumptions, we find that no more than a few percent of Earthâ s water can be attributed to comets, in agreement with the constraints derived from D/H. Our results also suggest that a significant part of Earthâ s atmospheric nitrogen might come from comets. Since the [SUP]15[/SUP]N/[SUP]14[/SUP]N isotopic ratio is not different in Oort-cloud and Kuiper-belt comets, our estimates apply to the contribution of both types of objects. [less ▲]

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See detailWater and related chemistry in the solar system. A guaranteed time key programme for Herschel
Hartogh, P.; Lellouch, E.; Crovisier, J. et al

in Planetary and Space Science (2009), 57

â Water and related chemistry in the Solar Systemâ is a Herschel Space Observatory Guaranteed-Time Key Programme. This project, approved by the European Space Agency, aims at determining the distribution ... [more ▼]

â Water and related chemistry in the Solar Systemâ is a Herschel Space Observatory Guaranteed-Time Key Programme. This project, approved by the European Space Agency, aims at determining the distribution, the evolution and the origin of water in Mars, the outer planets, Titan, Enceladus and the comets. It addresses the broad topic of water and its isotopologues in planetary and cometary atmospheres. The nature of cometary activity and the thermodynamics of cometary comae will be investigated by studying water excitation in a sample of comets. The D/H ratio, the key parameter for constraining the origin and evolution of Solar System species, will be measured for the first time in a Jupiter-family comet. A comparison with existing and new measurements of D/H in Oort-cloud comets will constrain the composition of pre-solar cometary grains and possibly the dynamics of the protosolar nebula. New measurements of D/H in giant planets, similarly constraining the composition of proto-planetary ices, will be obtained. The D/H and other isotopic ratios, diagnostic of Marsâ atmosphere evolution, will be accurately measured in H[SUB]2[/SUB]O and CO. The role of water vapor in Marsâ atmospheric chemistry will be studied by monitoring vertical profiles of H[SUB]2[/SUB]O and HDO and by searching for several other species (and CO and H[SUB]2[/SUB]O isotopes). A detailed study of the source of water in the upper atmosphere of the Giant Planets and Titan will be performed. By monitoring the water abundance, vertical profile, and input fluxes in the various objects, and when possible with the help of mapping observations, we will discriminate between the possible sources of water in the outer planets (interplanetary dust particles, cometary impacts, and local sources). In addition to these inter-connected objectives, serendipitous searches will enhance our knowledge of the composition of planetary and cometary atmospheres. [less ▲]

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See detailRevisit to Nuclear Spin Temperature of Ammonia in Comets
Shinnaka, Yoshiharu; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in Bulletin of the American Astronomical Society (2009, September 01), 41

Comets had formed from dust and icy materials in the solar nebula 4.6 Gyrs ago. The cometary materials are considered as the most pristine in the solar system and both dust grains and icy materials in ... [more ▼]

Comets had formed from dust and icy materials in the solar nebula 4.6 Gyrs ago. The cometary materials are considered as the most pristine in the solar system and both dust grains and icy materials in comets have been used to investigate the formation conditions of the solar system. One of interesting primordial characters is a nuclear spin temperature (related to an ortho-to-para ratio; OPR) of cometary molecules such as H2O, NH3, etc. The nuclear spin temperatures probably reflect the molecular formation temperatures in the solar nebula (or in the presolar molecular cloud). In this work, we analyzed high dispersion optical spectra of C/2001 Q4 (NEAT), C/2000 WM1 (LINEAR), 88P/Howell, fragments B and C of 73P/Schwassmann-Wachmann 3 and 8P/Tuttle. Our observations were performed by the Ultraviolet and Visual Echelle Spectrograph (UVES) mounted on the Very Large Telescope (VLT) in Chile and the High Dispersion Spectrograph (HDS) mounted on the Subaru telescope in Hawaii. We determined nuclear spin temperatures of NH3 in five comets based on optical spectra of NH2. The nuclear spin temperatures of NH3 can be obtained from OPRs of NH2. We used the (0,9,0) ro-vibronic band at 610nm in this work. Absorption lines (by the telluric atmosphere) and cometary C2 emission lines blended with NH2 emission lines were also taken into account in our analysis. These lines have never been considered in previous studies. The origin of icy materials in the five comets will be discussed based on these results. [less ▲]

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See detailIsotopic Ratios in Comets: Status and Perspectives
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Hutsemekers, Damien ULg et al

in Earth, Moon, and Planets (2009), 105

Isotopic abundance ratios are excellently suited to probe the origin of solar system matter. We review the recent measurements of the isotopic ratios of the light elements (D/H, [SUP]12[/SUP]C/[SUP]13 ... [more ▼]

Isotopic abundance ratios are excellently suited to probe the origin of solar system matter. We review the recent measurements of the isotopic ratios of the light elements (D/H, [SUP]12[/SUP]C/[SUP]13[/SUP]C, [SUP]16[/SUP]O/[SUP]18[/SUP]O, [SUP]14[/SUP]N/[SUP]15[/SUP]N, [SUP]32[/SUP]S/[SUP]34[/SUP]S) in cometary dust and gas and discuss briefly their implications. Special emphasis will be put on the determinations and progress performed in the field over the past years thanks to high resolution spectroscopy of cometary comae obtained with the ESO Very Large Telescope. Future perspectives from space missions and ground-based observations with new large and extremely large telescopes operating in the optical, infrared and submillimeter wavelengths will be presented. [less ▲]

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See detailThe CN isotopic ratios in comets
Manfroid, Jean ULg; Jehin, Emmanuel ULg; Hutsemekers, Damien ULg et al

in Astronomy and Astrophysics (2009), 503

Our aim is to determine the isotopic ratios [SUP]12[/SUP]C/[SUP]13[/SUP]C and [SUP]14[/SUP]N/[SUP]15[/SUP]N in a variety of comets and link these measurements to the formation and evolution of the solar ... [more ▼]

Our aim is to determine the isotopic ratios [SUP]12[/SUP]C/[SUP]13[/SUP]C and [SUP]14[/SUP]N/[SUP]15[/SUP]N in a variety of comets and link these measurements to the formation and evolution of the solar system. The [SUP]12[/SUP]C/[SUP]13[/SUP]C and [SUP]14[/SUP]N/[SUP]15[/SUP]N isotopic ratios are measured for the CN radical by means of high-resolution optical spectra of the R branch of the B-X (0, 0) violet band. 23 comets from different dynamical classes have been observed, sometimes at various heliocentric and nucleocentric distances, in order to estimate possible variations of the isotopic ratios in parent molecules. The [SUP]12[/SUP]C/[SUP]13[/SUP]C and [SUP]14[/SUP]N/[SUP]15[/SUP]N isotopic ratios in CN are remarkably constant (average values of, respectively, 91.0 ± 3.6 and 147.8 ± 5.7) within our measurement errors, for all comets whatever their origin or heliocentric distance. While the carbon isotopic ratio does agree with the terrestrial value (89), the nitrogen ratio is a factor of two lower than the terrestrial value (272), indicating a fractionation in the early solar system, or in the protosolar nebula, common to all the comets of our sample. This points towards a common origin of the comets independently of their birthplaces, and a relationship between HCN and CN. Appendices and Table [see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programmes ID 268.C-5570, 270.C-5043, 073.C-0525, 274.C-5015 and 075.C-0355(A). [less ▲]

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See detailA Multi-Wavelength Simultaneous Study of the Composition of the Halley Family Comet 8P/Tuttle
Jehin, Emmanuel ULg; Bockelée-Morvan, Dominique; Dello Russo, N. et al

in Earth, Moon, and Planets (2009), 105

We report on simultaneous optical and infrared observations of the Halley Family comet 8P/Tuttle performed with the ESO Very Large Telescope. Such multi-wavelength and coordinated observations are a good ... [more ▼]

We report on simultaneous optical and infrared observations of the Halley Family comet 8P/Tuttle performed with the ESO Very Large Telescope. Such multi-wavelength and coordinated observations are a good example of what can be done to support space missions. From high resolution optical spectroscopy of the CN (0,0) 388 nm and NH[SUB]2[/SUB] (0,9,0) 610 nm bands using UVES at UT2 we determined [SUP]12[/SUP]C/[SUP]13[/SUP]C = 90 ± 10 and [SUP]14[/SUP]N/[SUP]15[/SUP]N = 150 ± 20 in CN and we derived a nuclear spin temperature of NH[SUB]3[/SUB] of 29 ± 1 K. These values are similar to those found in Oort-Cloud and Jupiter Family comets. From low resolution long slit spectroscopy with FORS1 at UT2 we determined the CN, C[SUB]3[/SUB] and C[SUB]2[/SUB] production rates and the parent and daughter scale lengths up to 5.2 10[SUP]5[/SUP] km tailward. From high resolution IR spectroscopy with CRIRES at UT1 we measured simultaneously the production rates and mixing ratios of H[SUB]2[/SUB]O, HCN, C[SUB]2[/SUB]H[SUB]2[/SUB], CH[SUB]4[/SUB], C[SUB]2[/SUB]H[SUB]6[/SUB], and CH[SUB]3[/SUB]OH. [less ▲]

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See detailWater and related chemistry in the Solar System. A Guaranteed Time Key Programme for Herschel
Hartogh, P.; Crovisier, J.; Lellouch, E. et al

in EPSC Abstracts 2009 (2009)

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See detailThe 16OH/18OH and OD/OH isotope ratios in comet C/2002 T7 (LINEAR)
Hutsemekers, Damien ULg; Manfroid, Jean ULg; Jehin, Emmanuel ULg et al

in Astronomy and Astrophysics (2008), 490(Letters), 31-34

The [SUP]16[/SUP]OH/[SUP]18[/SUP]OH and OD/OH isotope ratios are measured in the Oort-Cloud comet C/2002 T7 (LINEAR) through ground-based observations of the OH A [SUP]2[/SUP]Σ[SUP]+[/SUP] - X [SUP]2 ... [more ▼]

The [SUP]16[/SUP]OH/[SUP]18[/SUP]OH and OD/OH isotope ratios are measured in the Oort-Cloud comet C/2002 T7 (LINEAR) through ground-based observations of the OH A [SUP]2[/SUP]Σ[SUP]+[/SUP] - X [SUP]2[/SUP]Π[SUB]i[/SUB] ultraviolet bands at 3063 à (0, 0) and 3121 à (1, 1) obtained with the Very Large Telescope (VLT) feeding the Ultraviolet-Visual Echelle Spectrograph (UVES). From the [SUP]16[/SUP]OH/[SUP]18[/SUP]OH ratio, we find [SUP]16[/SUP]O/[SUP]18[/SUP]O = 425 ± 55, equal within the uncertainties to the terrestrial value and to the ratio measured in other comets, although marginally smaller. We also estimate OD/OH from which we derive D/H = 2.5 ± 0.7à 10[SUP]-4[/SUP] in water. This value is compatible with the water D/H ratios evaluated in other comets and is marginally higher than the terrestrial value. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programme 073.C-0525). [less ▲]

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See detailIsotopic abundance in the CN coma of comets: Ten years of measurements
Schulz, R.; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in Planetary and Space Science (2008), 56

Over the past 10 years the isotopic ratios of carbon ([SUP]12[/SUP]C/[SUP]13[/SUP]C) and nitrogen ([SUP]14[/SUP]N/[SUP]15[/SUP]N) have been determined for a dozen comets, bright enough to allow obtaining ... [more ▼]

Over the past 10 years the isotopic ratios of carbon ([SUP]12[/SUP]C/[SUP]13[/SUP]C) and nitrogen ([SUP]14[/SUP]N/[SUP]15[/SUP]N) have been determined for a dozen comets, bright enough to allow obtaining the required measurements from the ground. The ratios were derived from high-resolution spectra of the CN coma measured in the B[SUP]2[/SUP]â [SUP]+[/SUP]â X[SUP]2[/SUP]â [SUP]+[/SUP] (0, 0) emission band around 387 nm. The observed comets belong to different dynamical classes, including dynamically new as well as long- and short-period comets from the Halley- and Jupiter-family. In some cases the comets could be observed at various heliocentric distances. All values determined for the carbon and nitrogen isotopic ratios were consistent within the error margin irrespective of the type of comet or the heliocentric distance at which it was observed. Our investigations resulted in average ratios of [SUP]12[/SUP]C/[SUP]13[/SUP]C=91±21 and nitrogen [SUP]14[/SUP]N/[SUP]15[/SUP]N=141±29. Whilst the value for the carbon isotopic ratio is in good agreement with the solar and terrestrial value of 89, the nitrogen isotopic ratio is very different from the telluric value of 272. [less ▲]

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See detailHigh-dispersion Spectroscopic Observations Of 8P/Tuttle With VLT/CRIRES
Kobayashi, Hitomi; Bockelee-Morvan, D.; Dello Russo, N. et al

in Bulletin of the American Astronomical Society (2008, September 01), 40

We present near-infrared observations of organic molecules in comet 8P/Tuttle. Comet 8P/Tuttle is a Halley-type comet and its last perihelion was in early January 2008. Our observations were carried out ... [more ▼]

We present near-infrared observations of organic molecules in comet 8P/Tuttle. Comet 8P/Tuttle is a Halley-type comet and its last perihelion was in early January 2008. Our observations were carried out on January 28 and February 4 using CRIRES (CRyogenic high-resolution InfraRed Echelle Spectrograph) at the Very Large Telescope (VLT). We used a 0.2" slit which provided a spectral resolving power of 80,000. We detected H[SUB]2[/SUB]O, OH, HCN, C[SUB]2[/SUB]H[SUB]2[/SUB] on Jan 28, and H[SUB]2[/SUB]O, OH, CH[SUB]4[/SUB], C[SUB]2[/SUB]H[SUB]6[/SUB], and CH[SUB]3[/SUB]OH on Feb 4. We find that 8P/Tuttle is depleted in HCN, C[SUB]2[/SUB]H[SUB]2[/SUB] and C[SUB]2[/SUB]H[SUB]6[/SUB] relative to H[SUB]2[/SUB]O compared with most other Oort cloud comets studied to date. Perhaps these depletions suggest that 8P/Tuttle formed in a different region from most Oort cloud comets, but it is also possible that the depletions are caused by repeated passages through the inner solar system. [less ▲]

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See detailAxions & Polarisation of Quasars
Payez, Alexandre ULg; Cudell, Jean-René ULg; Hutsemekers, Damien ULg

Poster (2008, May 21)

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See detailLarge Excess of Heavy Nitrogen in Both Hydrogen Cyanide and Cyanogen from Comet 17P/Holmes
Bockelée-Morvan, D.; Biver, N.; Jehin, Emmanuel ULg et al

in Astrophysical Journal (2008), 679(Letters), 49-52

From millimeter and optical observations of the Jupiter-family comet 17P/Holmes performed soon after its huge outburst of 2007 October 24, we derive [SUP]14[/SUP]N/[SUP]15[/SUP]N = 139 +/- 26 in HCN and ... [more ▼]

From millimeter and optical observations of the Jupiter-family comet 17P/Holmes performed soon after its huge outburst of 2007 October 24, we derive [SUP]14[/SUP]N/[SUP]15[/SUP]N = 139 +/- 26 in HCN and [SUP]14[/SUP]N/[SUP]15[/SUP]N = 165 +/- 40 in CN, establishing that HCN has the same nonterrestrial isotopic composition as CN. The same conclusion is obtained for the long-period comet C/1995 O1 (Hale-Bopp) after a reanalysis of previously published measurements. These results are compatible with HCN being the prime parent of CN in cometary atmospheres. The [SUP]15[/SUP]N excess relative to the Earth's atmospheric value indicates that N-bearing volatiles in the solar nebula underwent important N isotopic fractionation at some stage of solar system formation. HCN molecules never isotopically equilibrated with the main nitrogen reservoir in the solar nebula before being incorporated in Oort Cloud and Kuiper Belt comets. The [SUP]12[/SUP]C/[SUP]13[/SUP]C ratios in HCN and CN are measured to be consistent with the terrestrial value. [less ▲]

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