References of "Manfroid, Jean"
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See detailThe small binary asteroid (939) Isberga
Carry, B.; Matter, A.; Scheirich, P. et al

in Icarus (2015), 248

In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here at characterizing the surface composition, mutual orbit, size, mass ... [more ▼]

In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here at characterizing the surface composition, mutual orbit, size, mass, and density of the small main-belt binary asteroid (939) Isberga. For that, we conduct a suite of multi-technique observations, including optical lightcurves over many epochs, near-infrared spectroscopy, and interferometry in the thermal infrared. We develop a simple geometric model of binary systems to analyze the interferometric data in combination with the results of the lightcurve modeling. From spectroscopy, we classify Ibserga as a Sq-type asteroid, consistent with the albedo of 0.14<SUB>-0.06</SUB><SUP>+0.09</SUP> (all uncertainties are reported as 3-σ range) we determine (average albedo of S-types is 0.197 ± 0.153, see Pravec et al. (Pravec et al. [2012]. Icarus 221, 365-387). Lightcurve analysis reveals that the mutual orbit has a period of 26.6304 ± 0.0001 h, is close to circular (eccentricity lower than 0.1), and has pole coordinates within 7° of (225°, +86°) in Ecliptic J2000, implying a low obliquity of 1.5<SUB>-1.5</SUB><SUP>+6.0</SUP> deg . The combined analysis of lightcurves and interferometric data allows us to determine the dimension of the system and we find volume-equivalent diameters of 12.4<SUB>-1.2</SUB><SUP>+2.5</SUP> km and 3.6<SUB>-0.3</SUB><SUP>+0.7</SUP> km for Isberga and its satellite, circling each other on a 33 km wide orbit. Their density is assumed equal and found to be 2.91<SUB>-2.01</SUB><SUP>+1.72</SUP> gcm<SUP>-3</SUP> , lower than that of the associated ordinary chondrite meteorites, suggesting the presence of some macroporosity, but typical of S-types of the same size range (Carry [2012]. Planet. Space Sci. 73, 98-118). The present study is the first direct measurement of the size of a small main-belt binary. Although the interferometric observations of Isberga are at the edge of MIDI capabilities, the method described here is applicable to others suites of instruments (e.g., LBT, ALMA). [less ▲]

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See detailThe non-convex shape of (234) Barbara, the first Barbarian
Tanga, Paolo; Carry, B.; Colas, F. et al

in Monthly Notices of the Royal Astronomical Society (2015)

Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extremely rich in refractory inclusions, the oldest material ever found in the Solar System. It exhibits ... [more ▼]

Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extremely rich in refractory inclusions, the oldest material ever found in the Solar System. It exhibits several peculiar features, most notably its polarimetric behavior. In recent years other objects sharing the same property (collectively known as ”Barbarians”) have been discovered. Interferometric observations in the mid-infrared with the ESO VLTI suggested that (234) Barbara might have a bi-lobated shape or even a large companion satellite. We use a large set of 57 optical lightcurves acquired between 1979 and 2014, together with the timings of two stellar occultations in 2009, to determine the rotation period, spin-vector coordinates, and 3-D shape of (234) Barbara, using two different shape reconstruction algorithms. By using the lightcurves combined to the results obtained from stellar occultations, we are able to show that the shape of (234) Barbara exhibits large concave areas. Possible links of the shape to the polarimetric properties and the object evolution are discussed. We also show that VLTI data can be modeled without the presence of a satellite [less ▲]

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See detailThe binary near-Earth Asteroid (175706) 1996 FG3 - An observational constraint on its orbital evolution
Scheirich, P.; Pravec, P.; Jacobson, S. A. et al

in Icarus (2015), 245

Using our photometric observations taken between April 1996 and January 2013 and other published data, we derived properties of the binary near-Earth Asteroid (175706) 1996 FG<SUB>3</SUB> including new ... [more ▼]

Using our photometric observations taken between April 1996 and January 2013 and other published data, we derived properties of the binary near-Earth Asteroid (175706) 1996 FG<SUB>3</SUB> including new measurements constraining evolution of the mutual orbit with potential consequences for the entire binary asteroid population. We also refined previously determined values of parameters of both components, making 1996 FG<SUB>3</SUB> one of the most well understood binary asteroid systems. With our 17-year long dataset, we determined the orbital vector with a substantially greater accuracy than before and we also placed constraints on a stability of the orbit. Specifically, the ecliptic longitude and latitude of the orbital pole are 266 ° and - 83 ° , respectively, with the mean radius of the uncertainty area of 4 ° , and the orbital period is 16.1508 ± 0.0002 h (all quoted uncertainties correspond to 3σ). We looked for a quadratic drift of the mean anomaly of the satellite and obtained a value of 0.04 ± 0.20 deg /yr<SUP>2</SUP> , i.e., consistent with zero. The drift is substantially lower than predicted by the pure binary YORP (BYORP) theory of McMahon and Scheeres (McMahon, J., Scheeres, D. [2010]. Icarus 209, 494-509) and it is consistent with the tigidity and quality factor of μQ = 1.3 ×10<SUP>7</SUP> Pa using the theory that assumes an elastic response of the asteroid material to the tidal forces. This very low value indicates that the primary of 1996 FG<SUB>3</SUB> is a 'rubble pile', and it also calls for a re-thinking of the tidal energy dissipation in close asteroid binary systems. [less ▲]

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See detailMonte Carlo Simulation of Metastable Oxygen Photochemistry in Cometary Atmospheres
Bisikalo, D. V.; Shematovich, V. I.; Gérard, Jean-Claude ULg et al

in The Astrophysical Journal (2015), 798

Cometary atmospheres are produced by the outgassing of material, mainly H[SUB]2[/SUB]O, CO, and CO[SUB]2[/SUB] from the nucleus of the comet under the energy input from the Sun. Subsequent photochemical ... [more ▼]

Cometary atmospheres are produced by the outgassing of material, mainly H[SUB]2[/SUB]O, CO, and CO[SUB]2[/SUB] from the nucleus of the comet under the energy input from the Sun. Subsequent photochemical processes lead to the production of other species generally absent from the nucleus, such as OH. Although all comets are different, they all have a highly rarefied atmosphere, which is an ideal environment for nonthermal photochemical processes to take place and influence the detailed state of the atmosphere. We develop a Monte Carlo model of the coma photochemistry. We compute the energy distribution functions (EDF) of the metastable O([SUP]1[/SUP]D) and O([SUP]1[/SUP]S) species and obtain the red (630 nm) and green (557.7 nm) spectral line shapes of the full coma, consistent with the computed EDFs and the expansion velocity. We show that both species have a severely non-Maxwellian EDF, that results in broad spectral lines and the suprathermal broadening dominates due to the expansion motion. We apply our model to the atmosphere of comet C/1996 B2 (Hyakutake) and 103P/Hartley 2. The computed width of the green line, expressed in terms of speed, is lower than that of the red line. This result is comparable to previous theoretical analyses, but in disagreement with observations. We explain that the spectral line shape does not only depend on the exothermicity of the photochemical production mechanisms, but also on thermalization, due to elastic collisions, reducing the width of the emission line coming from the O([SUP]1[/SUP]D) level, which has a longer lifetime. [less ▲]

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See detailForbidden oxygen lines at various nucleocentric distances in comets
Decock, Alice ULg; Jehin, Emmanuel ULg; Rousselot, P. et al

in Astronomy and Astrophysics (2015), 573

Aims: We study the formation of the [OI] lines - that is, 5577.339 Å (the green line), 6300.304 Å and 6363.776 Å (the two red lines) - in the coma of comets and determine the parent species of the oxygen ... [more ▼]

Aims: We study the formation of the [OI] lines - that is, 5577.339 Å (the green line), 6300.304 Å and 6363.776 Å (the two red lines) - in the coma of comets and determine the parent species of the oxygen atoms using the ratio of the green-to-red-doublet emission intensity, I[SUB]5577[/SUB]/(I[SUB]6300[/SUB] + I[SUB]6364[/SUB]), (hereafter the G/R ratio) and the line velocity widths. <BR /> Methods: We acquired high-resolution spectroscopic observations at the ESO Very Large Telescope of comets C/2002 T7 (LINEAR), 73P-C/Schwassmann-Wachmann 3, 8P/Tuttle, and 103P/Hartley 2 when they were close to Earth (<0.6 au). Using the observed spectra, which have a high spatial resolution (<60 km/pixel), we determined the intensities and widths of the three [OI] lines. We spatially extracted the spectra to achieve the best possible resolution of about 1-2'', that is, nucleocentric projected distances of 100 to 400 km depending on the geocentric distance of the comet. We decontaminated the [OI] green line from C[SUB]2[/SUB] lines blends that we identified. <BR /> Results: The observed G/R ratio in all four comets varies as a function of nucleocentric projected distance (between ~0.25 to ~0.05 within 1000 km). This is mainly due to the collisional quenching of O([SUP]1[/SUP]S) and O([SUP]1[/SUP]D) by water molecules in the inner coma. The observed green emission line width is about 2.5 km s[SUP]-1[/SUP] and decreases as the distance from the nucleus increases, which can be explained by the varying contribution of CO[SUB]2[/SUB] to the O([SUP]1[/SUP]S) production in the innermost coma. The photodissociation of CO[SUB]2[/SUB] molecules seem to produce O([SUP]1[/SUP]S) closer to the nucleus, while the water molecule forms all the O([SUP]1[/SUP]S) and O([SUP]1[/SUP]D) atoms beyond 10[SUP]3[/SUP] km. Thus we conclude that the main parent species producing O([SUP]1[/SUP]S) and O([SUP]1[/SUP]D) in the inner coma is not always the same. The observations have been interpreted in the framework of the previously described coupled-chemistry-emission model, and the upper limits of the relative abundances of CO[SUB]2[/SUB] were derived from the observed G/R ratios. Measuring the [OI] lines might provide a new way to determine the CO[SUB]2[/SUB] relative abundance in comets. Based on observations made with ESO Telescope at the La Silla Paranal Observatory under programs ID 073.C-0525, 277.C-5016, 080.C-0615 and 086.C-0958.Tables 3 and 4 are available in electronic form at <A href="http://www.aanda.org/10.1051/0004-6361/201424403/olm">http://www.aanda.org</A> [less ▲]

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See detailThe TRAPPIST comet survey in 2014
Jehin, Emmanuel ULg; Opitom, Cyrielle ULg; Manfroid, Jean ULg et al

in Bulletin of the American Astronomical Society (2014, November 01), 46

TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) is a 60-cm robotic telescope that has been installed in June 2010 at the ESO La Silla Observatory [1]. Operated from Liège (Belgium) it is ... [more ▼]

TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) is a 60-cm robotic telescope that has been installed in June 2010 at the ESO La Silla Observatory [1]. Operated from Liège (Belgium) it is devoted to the detection and characterisation of exoplanets and to the study of comets and other small bodies in the Solar System. A set of narrowband cometary filters designed by the NASA for the Hale-Bopp Observing Campaign [2] is permanently mounted on the telescope along with classic Johnson-Cousins filters. We describe here the hardware and the goals of the project. For relatively bright comets (V < 12) we measure several times a week the gaseous production rates (using a Haser model) and the spatial distribution of several species among which OH, NH, CN, C2 and C3 as well as ions like CO+. The dust production rates (Afrho) and color of the dust aredetermined through four dust continuum bands from the UV to the red (UC, BC, GC, RC filters). We will present the dust and gas production rates of the brightest comets observed in 2014: C/2012 K1 (PANSTARRS), C/2014 E2 (Jacques), C/2013 A1 (Siding Springs) and C/2013 V5 (Oukaimeden). Each of these comets have been observed at least once a week for several weeks to several months. Light curves with respect to the heliocentric distance will be presented and discussed. [1] Jehin et al., The Messenger, 145, 2-6, 2011.[2] Farnham et al., Icarus, 147, 180-204, 2000. [less ▲]

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See detailTRAPPIST monitoring of comet C/2013 A1 (Siding Spring)
Opitom, Cyrielle ULg; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in Bulletin of the American Astronomical Society (2014, November 01), 46

C/2013 A1 (Siding Spring) is a long period comet discovered by Robert H McNaught at Siding Spring Observatory in Australia on January 3, 2013 at 7.2 au from the Sun. This comet will make a close encounter ... [more ▼]

C/2013 A1 (Siding Spring) is a long period comet discovered by Robert H McNaught at Siding Spring Observatory in Australia on January 3, 2013 at 7.2 au from the Sun. This comet will make a close encounter with Mars on October 19, 2014. At this occasion the comet will be extensively observed both from Earth and from several orbiters around Mars.On September 20, 2013 when the comet was around 5 au from the Sun, we started a monitoring with the TRAPPIST robotic telescope installed at La Silla observatory [1]. A set of narrowband cometary filters designed by the NASA for the Hale-Bopp Observing Campaign [2] is permanently mounted on the telescope along with classic Johnson-Cousins B, V, Rc, and Ic filters.We observed the comet continuously at least once a week from September 20, 2013 to April 6, 2014 with broad band filters. We then recovered the comet on May 20. At this time we could detect the gas and started the observations with narrow band filters until early November, covering the close approach to Mars and the perihelion passage.We present here our first results about comet Siding Springs. From the images in the broad band filters and in the dust continuum filters we derived A(θ)fρ values [3] and studied the evolution of the comet activity with the heliocentric distance from September 20, 2013 to early November 2014. We could also detect gas since May 20, 2014. We thus derived gas production rates using a Haser model [4]. We present the evolution of gas production rates and gas production rates ratios with the heliocentric distance.Finally, we discuss the dust and gas coma morphology. [less ▲]

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See detailPhase resolved X-ray spectroscopy of HDE 228766: Probing the wind of an extreme Of+/WNLha star (Corrigendum)
Rauw, Grégor ULg; Mahy, Laurent; Nazé, Yaël ULg et al

in Astronomy and Astrophysics (2014), 569

Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and on data collected at the San Pedro ... [more ▼]

Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and on data collected at the San Pedro Mártir observatory (Mexico). Corrigendum [less ▲]

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See detailInvestigation of the stellar content in the western part of the Carina nebula
Kumar, Brajesh; Sharma, Saurabh; Manfroid, Jean ULg et al

in Astronomy and Astrophysics (2014), 567

Context. The low obscuration and proximity of the Carina nebula make it an ideal place to study the ongoing star formation process and impact of massive stars on low-mass stars in their surroundings. <BR ... [more ▼]

Context. The low obscuration and proximity of the Carina nebula make it an ideal place to study the ongoing star formation process and impact of massive stars on low-mass stars in their surroundings. <BR /> Aims: To investigate this process, we generated a new catalog of the pre-main-sequence stars in the Carina west (CrW) region and studied their nature and spatial distribution. We also determined various parameters (reddening, reddening law, age, mass), which are used further to estimate the initial mass function and K-band luminosity function for the region under study. <BR /> Methods: We obtained deep UBVRI Hα photometric data of the field situated to the west of the main Carina nebula and centered on WR 22. Medium-resolution optical spectroscopy of a subsample of X-ray selected objects along with archival data sets from Chandra, XMM-Newton and 2MASS surveys were used for the present study. Different sets of color-color and color-magnitude diagrams are used to determine reddening for the region and to identify young stellar objects (YSOs) and estimate their age and mass. <BR /> Results: Our spectroscopic results indicate that the majority of the X-ray sources are late spectral type stars. The region shows a large amount of differential reddening with minimum and maximum values of E(B - V) as 0.25 and 1.1 mag, respectively. Our analysis reveals that the total-to-selective absorption ratio R[SUB]V[/SUB] is ~3.7 ± 0.1, suggesting an abnormal grain size in the observed region. We identified 467 YSOs and studied their characteristics. The ages and masses of the 241 optically identified YSOs range from ~0.1 to 10 Myr and ~0.3 to 4.8 M[SUB]⊙[/SUB], respectively. However, the majority of them are younger than 1 Myr and have masses below 2 M[SUB]⊙[/SUB]. The high mass star WR 22 does not seem to have contributed to the formation of YSOs in the CrW region. The initial mass function slope, Γ, in this region is found to be -1.13 ± 0.20 in the mass range of 0.5 < M/M[SUB]⊙[/SUB] < 4.8. The K-band luminosity function slope (α) is also estimated as 0.31 ± 0.01. We also performed minimum spanning tree analysis of the YSOs in this region, which reveals that there are at least ten YSO cores associated with the molecular cloud, and that leads to an average core radius of 0.43 pc and a median branch length of 0.28 pc. Full Table 3 is only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A109">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A109</A> [less ▲]

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See detailPhase resolved X-ray spectroscopy of HDE 228766: Probing the wind of an extreme Of+/WNLha star
Rauw, Grégor ULg; Mahy, Laurent; Nazé, Yaël ULg et al

in Astronomy and Astrophysics (2014), 566

Context. HDE 228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star ... [more ▼]

Context. HDE 228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star collides with the wind of its O8 II companion, leading to relatively strong X-ray emission. <BR /> Aims: Measuring the orbital variations of the line-of-sight absorption toward the X-ray emission from the wind-wind interaction zone yields information on the wind densities of both stars. <BR /> Methods: X-ray spectra have been collected at three key orbital phases to probe the winds of both stars. Optical photometry has been gathered to set constraints on the orbital inclination of the system. <BR /> Results: The X-ray spectra reveal prominent variations of the intervening column density toward the X-ray emission zone, which are in line with the expectations for a wind-wind collision. We use a toy model to set constraints on the stellar wind parameters by attempting to reproduce the observed variations of the relative fluxes and wind optical depths at 1 keV. <BR /> Conclusions: The lack of strong optical eclipses sets an upper limit of ~ 68° on the orbital inclination. The analysis of the variations of the X-ray spectra suggests an inclination in the range 54-61° and indicates that the secondary wind momentum ratio exceeds that of the primary by at least a factor 5. Our models further suggest that the bulk of the X-ray emission arises from the innermost region of the wind interaction zone, which is from a region whose outer radius, as measured from the secondary star, lies between 0.5 and 1.5 times the orbital separation. Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and on data collected at the San Pedro Mártir observatory (Mexico). [less ▲]

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See detailExtremely Organic-rich Coma of Comet C/2010 G2 (Hill) during its Outburst in 2012
Kawakita, Hideyo; Dello Russo, Neil; Vervack, Ron et al

in Astrophysical Journal (2014), 788

We performed high-dispersion near-infrared spectroscopic observations of comet C/2010 G2 (Hill) at 2.5 AU from the Sun using NIRSPEC (R ≈ 25,000) at the Keck II Telescope on UT 2012 January 9 and 10 ... [more ▼]

We performed high-dispersion near-infrared spectroscopic observations of comet C/2010 G2 (Hill) at 2.5 AU from the Sun using NIRSPEC (R ≈ 25,000) at the Keck II Telescope on UT 2012 January 9 and 10, about a week after an outburst had occurred. Over the two nights of our observations, prominent emission lines of CH[SUB]4[/SUB] and C[SUB]2[/SUB]H[SUB]6[/SUB], along with weaker emission lines of H[SUB]2[/SUB]O, HCN, CH[SUB]3[/SUB]OH, and CO were detected. The gas production rate of CO was comparable to that of H[SUB]2[/SUB]O during the outburst. The mixing ratios of CO, HCN, CH[SUB]4[/SUB], C[SUB]2[/SUB]H[SUB]6[/SUB], and CH[SUB]3[/SUB]OH with respect to H[SUB]2[/SUB]O were higher than those for normal comets by a factor of five or more. The enrichment of CO and CH[SUB]4[/SUB] in comet Hill suggests that the sublimation of these hypervolatiles sustained the outburst of the comet. Some fraction of water in the inner coma might exist as icy grains that were likely ejected from nucleus by the sublimation of hypervolatiles. Mixing ratios of volatiles in comet Hill are indicative of the interstellar heritage without significant alteration in the solar nebula. [less ▲]

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See detailThe binary near-Earth asteroid (175706) 1996 FG3 - An observational constraint on its orbital stability
Scheirich, P.; Pravec, P.; Jacobson, S. A. et al

E-print/Working paper (2014)

Using our photometric observations taken between April 1996 and January 2013 and other published data, we derive properties of the binary near-Earth asteroid (175706) 1996 FG3 including new measurements ... [more ▼]

Using our photometric observations taken between April 1996 and January 2013 and other published data, we derive properties of the binary near-Earth asteroid (175706) 1996 FG3 including new measurements constraining evolution of the mutual orbit with potential consequences for the entire binary asteroid population. We also refined previously determined values of parameters of both components, making 1996 FG3 one of the most well understood binary asteroid systems. We determined the orbital vector with a substantially greater accuracy than before and we also placed constraints on a stability of the orbit. Specifically, the ecliptic longitude and latitude of the orbital pole are 266{\deg} and -83{\deg}, respectively, with the mean radius of the uncertainty area of 4{\deg}, and the orbital period is 16.1508 +\- 0.0002 h (all uncertainties correspond to 3sigma). We looked for a quadratic drift of the mean anomaly of the satellite and obtained a value of 0.04 +\- 0.20 deg/yr^2, i.e., consistent with zero. The drift is substantially lower than predicted by the pure binary YORP (BYORP) theory of McMahon and Scheeres (McMahon, J., Scheeres, D. [2010]. Icarus 209, 494-509) and it is consistent with the theory of an equilibrium between BYORP and tidal torques for synchronous binary asteroids as proposed by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D. [2011]. ApJ Letters, 736, L19). Based on the assumption of equilibrium, we derived a ratio of the quality factor and tidal Love number of Q/k = 2.4 x 10^5 uncertain by a factor of five. We also derived a product of the rigidity and quality factor of mu Q = 1.3 x 10^7 Pa using the theory that assumes an elastic response of the asteroid material to the tidal forces. This very low value indicates that the primary of 1996 FG3 is a 'rubble pile', and it also calls for a re-thinking of the tidal energy dissipation in close asteroid binary systems. [less ▲]

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See detailTRAPPIST monitoring of comet C/2012 F6 (Lemmon)
Opitom, Cyrielle ULg; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

Poster (2014, April)

C/2012 F6 (Lemmon) is a long period comet discovered by the Mount Lemmon Survey on 2012 March 23 at 5 AU from the sun. C/2012 F6 (Lemmon) reached perihelion on March 23, 2013 at 0.73 AU from the sun. In ... [more ▼]

C/2012 F6 (Lemmon) is a long period comet discovered by the Mount Lemmon Survey on 2012 March 23 at 5 AU from the sun. C/2012 F6 (Lemmon) reached perihelion on March 23, 2013 at 0.73 AU from the sun. In December 2012 the comet was unexpectedly bright, allowing us to make an extensive monitoring during several months with both broadband and narrowband filters to follow the evolution of the comet chemical composition. The monitoring was made with TRAPPIST robotic telescope installed at La Silla observatory [1]. TRAPPIST is a 60-cm telescope dedicated to the study of exoplanets and small bodies in the solar system. The telescope is equipped with a 2Kx2K FLI Proline CCD camera very sensitive in the blue and the red. A set of narrowband cometary filters designed by the NASA for the Hale-Bopp Observing Campaign [2] is permanently mounted on the telescope along with classic Johnson-Cousins B, V, Rc, and Ic filters. We observed the comet from December 11, 2012 to March 4, 2013 (pre-perihelion) and from April 29, 2013 to June 11, 2013 (post-perihelion). At least 2 or 3 observing runs per week were programmed during this period. We collected 1358 images on 52 nights. In January and February the comet visibility allowed us to make several long runs and to detect the comet rotational variability. From the comet images in narrowband filters we studied the gaseous coma chemical composition and activity by deriving OH, NH, CN, C2 and C3 production rates using a classical Haser model [3]. The production and properties of the dust component were studied through the observation of C/2012 F6 (Lemmon) with narrowband continuum filters at 344.2 nm (UC), 444.9 nm (BC), 525.7 nm (GC) and 713.0 nm (RC). We used A(θ)fρ [4] parameter as a proxy for the dust production. [less ▲]

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See detailToward a Unique Nitrogen Isotopic Ratio in Cometary Ices
Rousselot, Philippe; Pirali, Olivier; Jehin, Emmanuel ULg et al

in Astrophysical Journal Letters (2014), 780

Determination of the nitrogen isotopic ratios in different bodies of the solar system provides important information regarding the solar system's origin. We unambiguously identified emission lines in ... [more ▼]

Determination of the nitrogen isotopic ratios in different bodies of the solar system provides important information regarding the solar system's origin. We unambiguously identified emission lines in comets due to the [SUP]15[/SUP]NH[SUB]2[/SUB] radical produced by the photodissociation of [SUP]15[/SUP]NH[SUB]3[/SUB]. Analysis of our data has permitted us to measure the [SUP]14[/SUP]N/[SUP]15[/SUP]N isotopic ratio in comets for a molecule carrying the amine (-NH) functional group. This ratio, within the error, appears similar to that measured in comets in the HCN molecule and the CN radical, and lower than the protosolar value, suggesting that N[SUB]2[/SUB] and NH[SUB]3[/SUB] result from the separation of nitrogen into two distinct reservoirs in the solar nebula. This ratio also appears similar to that measured in Titan's atmospheric N[SUB]2[/SUB], supporting the hypothesis that, if the latter is representative of its primordial value in NH[SUB]3[/SUB], these bodies were assembled from building blocks sharing a common formation location. [less ▲]

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See detailExtremely Organic-rich Coma of Comet C/2010 G2 (Hill) during its Outburst in 201
Kawakita, H; Dello Russo; Vervack, R et al

in Astrophysical Journal (2014)

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See detailThe tumbling spin state of (99942) Apophis
Pravec, P; Scheirich, P; Ďurech, J et al

in Icarus (2014), 233

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See detailContinued activity in P/2013 P5 PANSTARRS - The comet that should not be
Hainaut, O. R.; Boehnhardt, H.; Snodgrass, C. et al

in Astronomy and Astrophysics (2014)

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See detailA ring system detected around the Centaur (10199) Chariklo
Braga-Ribas; Sicardy; Ortiz et al

in Nature (2014)

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See detailHerschel observations of gas and dust in comet C/2006 W3 (Christensen) at 5 AU from the Sun
de Val-Borro, M; Bockelée-Morvan, D; Jehin, Emmanuel ULg et al

in Astronomy and Astrophysics (2014)

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