References of "Manfroid, Jean"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 20 of 655 1 2 3 4 5 6     TRAPPIST photometry and imaging monitoring of comet C/2013 R1 (Lovejoy): Implications for the origin of daughter speciesOpitom, Cyrielle ; Jehin, Emmanuel ; Manfroid, Jean et alin Astronomy and Astrophysics (2015), 584We report the results of the narrow-band photometry and imaging monitoring of comet C/2013 R1 (Lovejoy) with the robotic telescope TRAPPIST (La Silla observatory). We gathered around 400 images over 8 ... [more ▼]We report the results of the narrow-band photometry and imaging monitoring of comet C/2013 R1 (Lovejoy) with the robotic telescope TRAPPIST (La Silla observatory). We gathered around 400 images over 8 months pre- and post-perihelion between September 12, 2013 and July 6, 2014. We followed the evolution of the OH, NH, CN, C[SUB]3[/SUB], and C[SUB]2[/SUB] production rates computed with the Haser model, as well as the evolution of the dust production. All five gas species display an asymmetry about perihelion, since the rate of brightening is steeper than the rate of fading. The study of the coma morphology reveals gas and dust jets that indicate one or several active zone(s) on the nucleus. The dust, C[SUB]2[/SUB], and C[SUB]3[/SUB] morphologies present some similarities, while the CN morphology is different. OH and NH are enhanced in the tail direction. The study of the evolution of the comet activity shows that the OH, NH, and C[SUB]2[/SUB] production rate evolution with the heliocentric distance is correlated to the dust evolution. The CN and, to a lesser extent, the C[SUB]3[/SUB] do not display such a correlation with the dust. This evidence and the comparison with parent species production rates indicate that C[SUB]2[/SUB] and C[SUB]3[/SUB], on one hand, and OH and NH, on the other, could be - at least partially - released from organic - rich grains and icy grains. On the contrary, all evidences point to HCN being the main parent of CN in this comet. [less ▲]Detailed reference viewed: 35 (10 ULg) L'astronomie dans le monde - 12/2015Manfroid, Jean Article for general public (2015)VFTS 352 - Une nouvelle composante de laVoie lactée - Érosion de l’atmosphère de Mars - Disque autour d’une naine blanche - Éruption du trou noir Mrk 335 - Comète 67P - Sucre et alcool cométaires ... [more ▼]VFTS 352 - Une nouvelle composante de laVoie lactée - Érosion de l’atmosphère de Mars - Disque autour d’une naine blanche - Éruption du trou noir Mrk 335 - Comète 67P - Sucre et alcool cométaires - Géantes rouges magnétiques [less ▲]Detailed reference viewed: 18 (1 ULg) Pluto's atmosphere from stellar occultations in 2012 and 2013Dias-Oliveira, Alex; Sicardy, Bruno; Lellouch, Emmanuel et alin Bulletin of the American Astronomical Society (2015, November 01), 47We present results from two Pluto stellar occultations observed on 18 July 2012 and 04 May 2013, and monitored respectively from five and six sites in South America. Both campaigns involved large ... [more ▼]We present results from two Pluto stellar occultations observed on 18 July 2012 and 04 May 2013, and monitored respectively from five and six sites in South America. Both campaigns involved large telescopes (including the 8.2-m VLT at ESO/Paranal). The high SNR ratios and multi-chord coverage provide amoung the best Pluto atmospheric profiles ever obtained from the ground.We show that a spherically symmetric, clear (no-haze) and pure N2 atmosphere with a unique temperature profile satisfactorily fits the twelve lightcurves provided by the two events. We find, however, a small but significant increase of pressure of 6% (6-sigma level) between the two dates, with values of 2.16 ± 0.2 and 2.30 ± 0.01 μbar at the reference radius 1275 km, respectively.We provide atmospheric constrains between 1190 km and 1450 km from Pluto's center, and we determine the temperature profile with accuracy of a few km in vertical scale. Our model shows a stratosphere with strong positive gradient between 1190 km (at 36 K, 11 μbar) and r =1215 km (6.0 μbar), where a temperature maximum of 110 K is reached. Above it is a mesosphere with negative thermal gradient of -0.2 K/km up to 1,390 km (0.25 μbar), at which point, the mesosphere connects itself to a more isothermal upper branch at 81 K. This profile provides (assuming no troposphere) a Pluto surface radius of 1190 ± 5 km, consistent with preliminary values obtained by New Horizons. Currently measured CO abundances are too low to explain the negative mesospheric thermal gradient. We explore the possibility of an HCN (recently detected by ALMA) cooling. This model, however, requires largely supersaturated HCN. Zonal winds and vertical compositional variations of the atmosphere are also unable to explain the observed mesospheric trend.These events are the last useful ground-based occultations recorded before the 29 June 2015 occultation observed from Australia and New Zealand, and before the NASA's New Horizons flyby of July 2015. This work can serve as a benchmark in the New Horizons context, enabling comparisons between ground-based and space results concerning Pluto's atmospheric structure and temporal evolution. [less ▲]Detailed reference viewed: 11 (2 ULg) Nitrogen Isotopic Ratios in Cometary NH2: Implication for 15N-fractionation in AmmoniaShinnaka, Yoshiharu; Kawakita, Hideyo; Jehin, Emmanuel et alin Bulletin of the American Astronomical Society (2015, November 01), 47Isotopic ratios in cometary molecules are diagnostic for the physico-chemical conditions where molecules formed and are processed, from the interstellar medium to the solar nebula. Usually temperatures at ... [more ▼]Isotopic ratios in cometary molecules are diagnostic for the physico-chemical conditions where molecules formed and are processed, from the interstellar medium to the solar nebula. Usually temperatures at the molecular formation control the fractionation of the heavier element in molecular species, e.g., D-fractionation in water.In cometary volatiles, the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in CN have been well observed (Manfroid et al. 2009, A&A, 503, 613, and reference therein) and is consistent with the ratio in HCN (a most probable parent of CN) measured in few comets (Bockelée-Morvan et al. 2008, ApJ, 679, L49). Those ratios are enriched compared to the proto-solar value by a factor of ~3. In contrast to those Nitriles, there are only few reports on [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in Ammonia (as Amine) (Rousselot et al. 2014, ApJ, 780, L17; Shinnaka et al. 2014, ApJ, 782, L16). Ammonia (NH[SUB]3[/SUB]) is usually the most abundant and HCN is the second most abundant N-bearing volatiles in cometary ice. Especially, recent observations of [SUP]15[/SUP]NH[SUB]2[/SUB] revealed the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in NH[SUB]3[/SUB] are comparable to those of CN. However, from the viewpoint of theoretical work, the enrichment of [SUP]15[/SUP]N in cometary NH[SUB]3[/SUB] cannot be reproduced by current chemical network models. Information about the diversity of the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in NH[SUB]3[/SUB] of individual comets is needed to understand the formation mechanisms/environments of NH[SUB]3[/SUB] in the early solar system.To clarify the diversity of the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in cometary NH[SUB]3[/SUB], we determine the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in NH[SUB]3[/SUB] for more than ten comets individually which include not only Oort cloud comets but also short period comets by using the high-resolution optical spectra of NH[SUB]2[/SUB]. These spectra were obtained with both the UVES mounted on the VLT in Chile and the HDS on the Subaru Telescope in Hawaii.The derived [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in NH[SUB]3[/SUB] for more than ten comets show high [SUP]15[/SUP]N-enrichment compared with the elemental abundances of nitrogen in the Sun by about factor of ~3 and has no large diversity depending on these dynamical properties. We discuss about the origin of the formation conditions of cometary NH[SUB]3[/SUB] and its physico-chemical evolution in the solar nebula based on our and other results.This work was supported by JSPS, 15J10864 (Y. Shinnaka). [less ▲]Detailed reference viewed: 13 (1 ULg) Five years of comet narrow band photometry and imaging with TRAPPISTOpitom, Cyrielle ; Jehin, Emmanuel ; Manfroid, Jean et alin Bulletin of the American Astronomical Society (2015, November 01), 47TRAPPIST is a 60-cm robotic telescope in La Silla Observatory [1] mainly dedicated to the study of exoplanets and comets. The telescope is equipped with a set of narrow band cometary filters designed by ... [more ▼]TRAPPIST is a 60-cm robotic telescope in La Silla Observatory [1] mainly dedicated to the study of exoplanets and comets. The telescope is equipped with a set of narrow band cometary filters designed by the NASA for the Hale-Bopp observing campaign [2]. Since its installation in 2010, we gathered a high quality and homogeneous data set of more than 30 bright comets observed with narrow band filters. Some comets were only observed for a few days but others have been observed weekly during several months on both sides of perihelion. From the images, we derived OH, NH, CN, C[SUB]2[/SUB], and C[SUB]3[/SUB] production rates using a Haser [3] model in addition to the Afρ parameter as a proxy for the dust production. We computed production rates ratios and the dust color for each comet to study their composition and followed the evolution of these ratios and colors with the heliocentric distance.The TRAPPIST data set, rich of more than 10000 images obtained and reduced in an homogeneous way, allows us to address several fundamental questions such as the pristine or evolutionary origin of composition differences among comets. The evolution of comet activity with the heliocentric distance, the differences between species, and from comet to comet, will be discussed. Finally, the first results about the one year campaign on comet C/2013 US10 (Catalina) and our recent work on the re-determination of Haser scalelengths will be presented.[1] Jehin et al., The Messenger, 145, 2-6, 2011[2] Farnham et al., Icarus, 147, 180-204, 2000[3] Haser, Bulletin de l’Académie Royal des Sciences de Belgique,63, 739, 1957 [less ▲]Detailed reference viewed: 16 (6 ULg) Joyaux cosmiques - 11/2015Manfroid, Jean Article for general public (2015)Éclipse double et triple - La galaxie naine du Sculpteur -M17Detailed reference viewed: 14 (0 ULg) L'astronomie dans le monde - 11/2015Manfroid, Jean Article for general public (2015)Jupiter chauds - L’habitabilité des planètesrocheuses - SOHO, la 3000e comète - Io - Anneaux de Saturne - Encelade - L’eau sur Mars - Comète 67P - Pluton - CharonDetailed reference viewed: 17 (0 ULg) New and updated convex shape models of asteroids based on optical data from a large collaboration networkHanuš, J.; Ďurech, J.; Oszkiewicz, D. A. et alE-print/Working paper (2015)Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical ... [more ▼]Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical properties of main-belt asteroids or large collisional families. We aim to increase the number of asteroid shape models and rotation states. Such results are an important input for various further studies such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides, in combination with known masses, bulk density estimates, but constrains also theoretical collisional and evolutional models of the Solar System. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as an input for the convex inversion method, and derive 3D shape models of asteroids, together with their rotation periods and orientations of rotation axes. The key ingredient is the support of more that one hundred observers who submit their optical data to publicly available databases. We present updated shape models for 36 asteroids, for which mass estimates are currently available in the literature or their masses will be most likely determined from their gravitational influence on smaller bodies, which orbital deflection will be observed by the ESA Gaia astrometric mission. This was achieved by using additional optical data from recent apparitions for the shape optimization. Moreover, we also present new shape model determinations for 250 asteroids, including 13 Hungarias and 3 near-Earth asteroids. [less ▲]Detailed reference viewed: 26 (5 ULg) Long-term activity and outburst of comet C/2013 A1 (Siding Spring) from narrow-band photometry and long-slit spectroscopyOpitom, Cyrielle ; Guilbert-Lepoutre, A.; Jehin, Emmanuel et alE-print/Working paper (2015)In this paper, we present a unique data set of more than one year's worth of regular observations of comet C/2013 A1(Siding Spring) with TRAPPIST in Chile, along with low-resolution spectra obtained with ... [more ▼]In this paper, we present a unique data set of more than one year's worth of regular observations of comet C/2013 A1(Siding Spring) with TRAPPIST in Chile, along with low-resolution spectra obtained with the ESO/VLT FORS 2 instrument. The comet made a close approach to Mars on October 19, 2014 and was then observed by many space and ground-based telescopes. We followed the evolution of the OH, NH, CN, $\mathrm{C_3}$, and $\mathrm{C_2}$ production rates as well as the $Af\rho$ parameter as a proxy for the dust production. We detected an outburst two weeks after perihelion, with gas and dust production rates being multiplied by a factor five within a few days. By modelling the shape of the CN and $\mathrm{C_2}$ radial profiles, we determined that the outburst happened around on November 10 around 15:30 UT ($\pm$ 5h) and measured a gas ejection velocity of $1.1\pm0.2$ km/s. We used a thermal evolution model to reproduce the activity pattern and outburst. Our results are consistent with the progressive formation of a dust mantle explaining the shallow dependence of gas production rates, which may be partially blown off during the outburst. We studied the evolution of gas composition, using various ratios such as CN/OH, $\mathrm{C_2}$/OH, or $\mathrm{C_3}$/OH, which showed little or no variation with heliocentric distance including at the time of the outburst. This indicates a relative level of homogeneity of the nucleus composition. [less ▲]Detailed reference viewed: 14 (5 ULg) Joyaux cosmiques - 10/2015Manfroid, Jean Article for general public (2015)ESO 378-1 - Amas IC 4651 -Recyclage cosmique - M2-9Detailed reference viewed: 9 (0 ULg) L'astronomie dans le monde - 10/2015Manfroid, Jean Article for general public (2015)Fonction initiale demasse - Markarian 231 - Extinction globale - Supernovæ fuyantes - Pluton - Anneaux de SaturneDetailed reference viewed: 13 (0 ULg) Joyaux cosmiques - 09/2015Manfroid, Jean Article for general public (2015)NGC 2367 - RCW 34 - Sh 2-274Detailed reference viewed: 9 (0 ULg) L'astronomie dans le monde - 09/2015Manfroid, Jean Article for general public (2015)Messenger -HD 219134b - GJ 436b - Kepler-452b - Un jumeau de Jupiter - Comète 67P - GaiaDetailed reference viewed: 13 (0 ULg) High-resolution spectra of comet C/2013 R1 (Lovejoy)Rousselot, P.; Decock, A.; Korsun, P. P. et alin Astronomy and Astrophysics (2015), 580Context. High-resolution spectra of comets permit deriving the physical properties of the coma. In the optical range, relative production rates can be computed, and information about isotopic ratios and ... [more ▼]Context. High-resolution spectra of comets permit deriving the physical properties of the coma. In the optical range, relative production rates can be computed, and information about isotopic ratios and the origin of oxygen atoms can be obtained.