Publications of Jean Manfroid
Bookmark and Share    
Full Text
See detailTRAPPIST: TRAnsiting Planets and PlanetesImals Small Telescope
Jehin, Emmanuel ULiege; Gillon, Michaël ULiege; Queloz, D. et al

in The Messenger (2011), 145

TRAPPIST is a 60-cm robotic telescope that was installed in April 2010 at the ESO La Silla Observatory. The project is led by the Astrophysics and Image Processing group (AIP) at the Department of ... [more ▼]

TRAPPIST is a 60-cm robotic telescope that was installed in April 2010 at the ESO La Silla Observatory. The project is led by the Astrophysics and Image Processing group (AIP) at the Department of Astrophysics, Geophysics and Oceanography (AGO) of the University of Liège, in close collaboration with the Geneva Observatory, and has been funded by the Belgian Fund for Scientific Research (F.R.S.-FNRS) and the Swiss National Science Foundation (SNF). It is devoted to the detection and characterisation of exoplanets and to the study of comets and other small bodies in the Solar System. We describe here the goals of the project and the hardware and present some results obtained during the first six months of operation. [less ▲]

Detailed reference viewed: 103 (8 ULiège)
Full Text
See detailL'astronomie dans le monde
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Wassonite, Krotite et autres; Hale-Bopp; Dawn; Tempel 1; Pluton; Io; Titan; 55 Cancri e; Écoulements dans le cratère Terby; Cinquante ans de l’homme dans l’espace

Detailed reference viewed: 2 (0 ULiège)
Full Text
See detailEPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign
Meech, K. J.; A'Hearn, M. F.; Adams, J. A. et al

in Astrophysical Journal (2011), 734(Letters), 11-9

Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible ... [more ▼]

Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4 hr. Starting in 2010 August the period changed from 16.6 hr to near 19 hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO[SUB]2[/SUB]-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production. [less ▲]

Detailed reference viewed: 84 (5 ULiège)
Full Text
See detailL'astronomie dans le monde
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Le cœur des géantes rouges; Sœurs du Soleil; Système triple; Messenger; Tourbillons de Vénus; Premières galaxies; Mars

Detailed reference viewed: 7 (0 ULiège)
Full Text
See detailL'astronomie dans le monde
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Eruption solaire; La formation planétaire en action; Amas de galaxies; Encelade; Impacts simultanés sur Mars; Cléopâtre; Carbone martien; Itokawa; Naines brunes

Detailed reference viewed: 8 (0 ULiège)
Full Text
See detailRencontres cométaires
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Full Text
See detailL'astronomie dans le monde
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Kepler, deuxième round; Premier instantané du Soleil à 360 degrés; Jupiter; WISE; Record de distance

Detailed reference viewed: 6 (0 ULiège)
Full Text
See detailOrtho-to-para Abundance Ratio (OPR) of Ammonia in 15 Comets: OPRs of Ammonia Versus 14N/15N Ratios in CN
Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi et al

in Astrophysical Journal (2011), 729

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices. We present OPRs of ammonia (NH[SUB]3[/SUB]) in 15 comets based on ... [more ▼]

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices. We present OPRs of ammonia (NH[SUB]3[/SUB]) in 15 comets based on optical high-dispersion spectroscopic observations of NH[SUB]2[/SUB], which is a photodissociation product of ammonia in the gaseous coma. The observations were mainly carried out with the VLT/UVES. The OPR of ammonia is estimated from the OPR of NH[SUB]2[/SUB] based on the observations of the NH[SUB]2[/SUB] (0, 9, 0) vibronic band. The absorption lines by the telluric atmosphere are corrected and the cometary C[SUB]2[/SUB] emission lines blended with NH[SUB]2[/SUB] lines are removed in our analysis. The ammonia OPRs show a cluster between 1.1 and 1.2 (this corresponds to a nuclear spin temperature of ~30 K) for all comets in our sample except for 73P/Schwassmann-Wachmann 3 (73P/SW3). Comet 73P/SW3 (both B- and C-fragments) shows the OPR of ammonia consistent with nuclear spin statistical weight ratio (1.0) that indicates a high-temperature limit as nuclear spin temperature. We compared the ammonia OPRs with other properties ([SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in CN, D/H ratios of water, and mixing ratios of volatiles). Comet 73P/SW3 is clearly different from the other comets in the plot of ammonia OPRs versus [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in CN. The ammonia OPRs of 1.0 and lower [SUP]15[/SUP]N-fractionation of CN in comet 73P/SW3 imply that icy materials in this comet formed under warmer conditions than other comets. Comets may be classified into two groups in the plot of ammonia OPRs against [SUP]14[/SUP]N/[SUP]15[/SUP]N ratios in CN. [less ▲]

Detailed reference viewed: 29 (5 ULiège)
Full Text
See detailStellar Occultation by Transneptunian Object (208996) 2003 AZ84
Braga-Ribas, F.; Sicardy, B.; Colas, F. et al

in Central Bureau Electronic Telegrams (2011), 2675

CBET 2675 available at Central Bureau for Astronomical Telegrams.

Detailed reference viewed: 28 (3 ULiège)
Full Text
See detailL'astronomie dans le monde
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

La période des Céphéides; ChaMP; MOAO; Des suies autour d’une exoplanète; Kepler-10b, une planète tellurique; Le nain se rebiffe; La roue réinventée; SOHO; Lacs de Titan

Detailed reference viewed: 12 (1 ULiège)
Full Text
See detailL’éclipse partielle du 4 janvier
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Detailed reference viewed: 10 (0 ULiège)
Full Text
See detailTRAPPIST: a robotic telescope dedicated to the study of planetary systems
Gillon, Michaël ULiege; Jehin, Emmanuel ULiege; Magain, Pierre ULiege et al

in EPJ Web of Conferences (2011, February 01), 11

We present here a new robotic telescope called TRAPPIST<xref ref-type="fn" rid="FN2">1</xref> (TRAnsiting Planets and PlanetesImals Small Telescope). Equipped with a high-quality CCD camera mounted on a 0 ... [more ▼]

We present here a new robotic telescope called TRAPPIST<xref ref-type="fn" rid="FN2">1</xref> (TRAnsiting Planets and PlanetesImals Small Telescope). Equipped with a high-quality CCD camera mounted on a 0.6 meter light weight optical tube, TRAPPIST has been installed in April 2010 at the ESO La Silla Observatory (Chile), and is now beginning its scientific program. The science goal of TRAPPIST is the study of planetary systems through two approaches: the detection and study of exoplanets, and the study of comets. We describe here the objectives of the project, the hardware, and we present some of the first results obtained during the commissioning phase. [less ▲]

Detailed reference viewed: 19 (2 ULiège)
Full Text
See detailL'astronomie dans le monde
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Un motif universel pour les géantes rouges; Jeune trou noir; Un essaim de vieilles étoiles; Une planète d’une autre galaxie; Crash majeur dans le Groupe local de galaxies; Ça ne tourne pas rond dans la ... [more ▼]

Un motif universel pour les géantes rouges; Jeune trou noir; Un essaim de vieilles étoiles; Une planète d’une autre galaxie; Crash majeur dans le Groupe local de galaxies; Ça ne tourne pas rond dans la Voie lactée; Le portrait de famille planétaire s’agrandit; Analyse de la première atmosphère d’une Super-Terre [less ▲]

Detailed reference viewed: 7 (0 ULiège)
Full Text
See detailLa dictature de l'horizon
Manfroid, Jean ULiege

in Ciel (Le) (2011), 73

Detailed reference viewed: 60 (2 ULiège)
Full Text
See detail(596) Scheila
Jehin, Emmanuel ULiege; Manfroid, Jean ULiege; Hutsemekers, Damien ULiege et al

in Central Bureau Electronic Telegrams (CBETs) (2011), 2632

E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Fonds National de la Recherche Scientifique, Liege University, report on broad- and narrow-band imaging of the (596) Scheila outburst (CBET ... [more ▼]

E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Fonds National de la Recherche Scientifique, Liege University, report on broad- and narrow-band imaging of the (596) Scheila outburst (CBET 2583) with the TRAPPIST 0.60-m telescope at La Silla, and on optical spectroscopy with the European Southern Observatory's Very Large Telescope (VLT) at Paranal. R-band imaging from 2010 Dec. 12.3 to 21.3 UT revealed two arc-like coma features expanding at a regular pace. The first such feature was 1' long on 2010 Dec. 12, oriented to the northeast and bending to p.a. 280 deg (the anti-solar direction). The second feature was shorter, 30" on Dec. 12, oriented to the south and bending to p.a. 230 deg. Both features were getting larger and fainter with time (4' and 2' long, respectively, on Dec. 21.3). A narrow 45"-long tail, opposite the sun (p.a. 280 deg), was also observed in good seeing. R-band images taken on 2011 Jan. 4.3 and 5.3 after the full moon allowed Jehin et al. to again observe these features, seen as 7' and 4' long, respectively -- and much fainter. This discards any sustained activity of the minor planet. Narrow-band images obtained on 2010 Dec. 12.3 with cometary filters do not show any contribution from gases. A 20-min optical spectrum was obtained with FORS2 at the VLT on Dec. 13.3; it does not show any extended cometary gaseous emissions, but only a spatially extended continuum due to dust-scattered sunlight. Short B, V, R, and I exposures performed nearly every two nights from 2010 Dec. 12.3 to 2011 Jan. 5.3 give a magnitude for the nuclear condensation of V = 14.2 +/- 0.1 over the whole period, in agreement with the "APmag" value reported in the Jet Propulsion Laboratory ephemeris. No flux variation of the nuclear condensation was observed. Those preliminary results are in favor of a collisional scenario to explain the outburst of (596) Scheila, rather than a cometary driven activity. This case might be similar to the outburst of comet P/2010 A2, which may have resulted from an impact of a minor planet (Snodgrass 2010, Nature 467, 814). [less ▲]

Detailed reference viewed: 32 (4 ULiège)
Full Text
See detailA photometric study of the Carina nebula region around WR 22
Kumar, Brajesh ULiege; Manfroid, Jean ULiege; Gosset, Eric ULiege et al

in Bulletin de la Societe Royale des Sciences de Liege (2011), 80

We performed the first photometric observations of a field situated around WR 22 in the Carina nebula region. We present and discuss the preliminary results of the study.

Detailed reference viewed: 33 (12 ULiège)
See detailAstronomie dans le monde
Manfroid, Jean ULiege

Article for general public (2011)

Detailed reference viewed: 2 (0 ULiège)
Full Text
See detailStudy of the forbidden oxygen lines in a dozen comets observed at the VLT (ESO)
Decock, Alice ULiege; Jehin, Emmanuel ULiege; Manfroid, Jean ULiege et al

in EPSC Abstracts 2011 (2011)

The forbidden lines are difficult to analyse because their detection requires high spectral and spatial resolutions. Their analysis is however interesting because it allows the determination of the ... [more ▼]

The forbidden lines are difficult to analyse because their detection requires high spectral and spatial resolutions. Their analysis is however interesting because it allows the determination of the spatial distribution and the production rate of the parent molecules, supposedly H2O which doesn't have any feature in the optical range. But as shown by Cochran [2] [3], some issues remain about the nature of the parents of the oxygen atoms. Moreover the width of the green line was found larger than that of the red lines. One of the goals of this study is to determine the parent species that photo-dissociate to produce oxygen atoms and see how this process depends on the heliocentric distance. We present here the results of the analysis of a homogeneous set of high quality spectra of 13 different comets observed with UVES at the ESO VLT since 2002 [4] [5]. [less ▲]

Detailed reference viewed: 28 (8 ULiège)
Full Text
See detail12C2/12C13C isotopic ratio in comets C/2001 Q4(NEAT) and C/2002 T7 (LINEAR)
Rousselot, P.; Jehin, Emmanuel ULiege; Manfroid, Jean ULiege et al

in EPSC Abstracts 2011 (2011)

The measurement of the carbon isotope abundances ratio in comets allows to constrain the conditions in the outer protosolar nebula. Different measurements of the 12C/13C ratio, using various molecules ... [more ▼]

The measurement of the carbon isotope abundances ratio in comets allows to constrain the conditions in the outer protosolar nebula. Different measurements of the 12C/13C ratio, using various molecules, have already been published for different solar system objects, such as the Sun, the Earth, the Moon, asteroids, planets or comets. So far all these measurements are consistent with 12C/13C' 90 but some significant differences have been seen. In comets this ratio is remarquably constant and equal to 91.0±3.6 [3] for studies based on CN radical but present larger variations with studies based on other radicals [1][5]. In this work we present a new analysis of this ratio, based on two different approachs for modeling the 12C2 and 12C13C emission spectrum and the (1,0) and (2,1) bandheads of 12C13C. Observational data obtained at high resolution (' 70, 000) using the 8.2-m Kueyen telescope (UT2) of the Very Large Telescope (VLT) with the Ultraviolet and Visual Echelle Spectrograph (UVES) instrument have been used to test our modeling and measure the 12C/13C ratio in two different comets: C/2001 Q4(NEAT) and C/2002 T7 (LINEAR). Our modeling and numerical results will be presented. [less ▲]

Detailed reference viewed: 16 (3 ULiège)
Full Text
See detailLong term photometric monitoring of comet 103P/Hartley2 with the new robotic TRAPPIST telescope
Jehin, Emmanuel ULiege; Manfroid, Jean ULiege; Hutsemekers, Damien ULiege et al

in EPSC Abstracts 2011 (2011)

We report on a long term monitoring of comet 103P/Hartley2 with six cometary narrow band filters using the TRAPPIST 0.60m telescope installed recently at the ESO La Silla observatory in Chile. This new ... [more ▼]

We report on a long term monitoring of comet 103P/Hartley2 with six cometary narrow band filters using the TRAPPIST 0.60m telescope installed recently at the ESO La Silla observatory in Chile. This new robotic telescope is dedicated to exoplanet and solar system research. The comet was observed with the cometary filters during 4 months, from Oct. 29 to Feb. 22. Since then the monitoring continues but only through the BVRI filters and about two times per week. Those observations allowed us to make a detailed light curve of the comet after its perihelion passage and derive production rates of the 4 main species (OH, CN, C2, C3) as well as the dust production rate (Afρ) over that period. The high sampling of our monitoring allowed us to find a periodicity in the gaseous light curves and to deduce a rotation period of 18.4h early November, slowing down to about 19h by the end of December. [less ▲]

Detailed reference viewed: 53 (7 ULiège)