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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 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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See detailEclipsing Am binary systems in the SuperWASP survey
Smalley, B.; Southworth, J.; Pintado, O. I. et al

in Astronomy and Astrophysics (2014), 564

The results of a search for eclipsing Am star binaries using photometry from the SuperWASP survey are presented. The light curves of 1742 Am stars fainter than V = 8.0 were analysed for the presence of ... [more ▼]

The results of a search for eclipsing Am star binaries using photometry from the SuperWASP survey are presented. The light curves of 1742 Am stars fainter than V = 8.0 were analysed for the presence of eclipses. A total of 70 stars were found to exhibit eclipses, with 66 having sufficient observations to enable orbital periods to be determined and 28 of which are newly identified eclipsing systems. Also presented are spectroscopic orbits for 5 of the systems. The number of systems and the period distribution is found to be consistent with that identified in previous radial velocity surveys of "classical" Am stars. [less ▲]

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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 detailEarly-type stars observed in the ESO UVES Paranal Observatory Project - IV. Studies of CN, CH+ and CH in the interstellar medium
Smoker, J.; Ledoux, C.; Jehin, Emmanuel ULg et al

in Monthly Notices of the Royal Astronomical Society (2013)

High spectral resolution (˜80 000) and signal-to-noise observations from the Ultraviolet and Visual Echelle Spectrograph Paranal Observatory Project (UVES-POP) are used to study the interstellar molecular ... [more ▼]

High spectral resolution (˜80 000) and signal-to-noise observations from the Ultraviolet and Visual Echelle Spectrograph Paranal Observatory Project (UVES-POP) are used to study the interstellar molecular lines CN (3874 Å), CH[SUP]+[/SUP] (3957, 4232 Å) and CH (3886, 4300 Å) towards 74 O- and B-type stellar sightlines. Additionally, archive data are presented for 140 ELODIE early-type stellar sightlines at R = 42 000, plus 25 FEROS at R = 48 000 and 3 UVES at R > 50 000, mainly in the CH[SUP]+[/SUP] (4232 Å) and CH (3886, 4300 Å) transitions. Detection rates are ˜45 per cent for CN and ˜67 per cent for the other lines in the POP sample, and ˜10-15 per cent for CH[SUP]+[/SUP] and CH lines in the additional sample. CH and CH[SUP]+[/SUP] are well correlated between log[N(CH) cm[SUP]-2[/SUP]]˜12-14, implying that these clouds are CH[SUP]+[/SUP]-like CH and not CN-like CH. CH is also very well correlated with Na I D in the range log[N(Na I cm[SUP]-2[/SUP]]) ˜12.2-14.2. A few sightlines show tentative velocity shifts of ˜2 km s[SUP]-1[/SUP] between CH and CH[SUP]+[/SUP], which appear to be caused by differences in component strength in blends, and hence do not provide firm evidence for shocks. Finally, we describe a search for [SUP]13[/SUP]CH[SUP]+[/SUP] in a sightline towards HD 76341. No [SUP]13[/SUP]CH[SUP]+[/SUP] is detected, placing a limit on the [SUP]13[/SUP]CH[SUP]+[/SUP] to [SUP]12[/SUP]CH[SUP]+[/SUP] ratio of ˜0.01. If a formal fit is attempted, the equivalent width ratio in the two isotopes is a factor ˜90 but with large errors. [less ▲]

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See detailA Photometric Study of the Hot Exoplanet WASP-19b
Lendl, M.; Gillon, Michaël ULg; Queloz, D. et al

in Astronomy and Astrophysics (2013), 552

Context. The sample of hot Jupiters that have been studied in great detail is still growing. In particular, when the planet transits its host star, it is possible to measure the planetary radius and the ... [more ▼]

Context. The sample of hot Jupiters that have been studied in great detail is still growing. In particular, when the planet transits its host star, it is possible to measure the planetary radius and the planet mass (with radial velocity data). For the study of planetary atmospheres, it is essential to obtain transit and occultation measurements at multiple wavelengths. Aims: We aim to characterize the transiting hot Jupiter WASP-19b by deriving accurate and precise planetary parameters from a dedicated observing campaign of transits and occultations. Methods: We have obtained a total of 14 transit lightcurves in the r'-Gunn, I-Cousins, z'-Gunn, and I + z' filters and 10 occultation lightcurves in z'-Gunn using EulerCam on the Euler-Swiss telescope and TRAPPIST. We also obtained one lightcurve through the narrow-band NB1190 filter of HAWK-I on the VLT measuring an occultation at 1.19 μm. We performed a global MCMC analysis of all new data, together with some archive data in order to refine the planetary parameters and to measure the occultation depths in z'-band and at 1.19 μm. Results: We measure a planetary radius of Rp = 1.376 ± 0.046 RJ, a planetary mass of Mp = 1.165 ± 0.068 MJ, and find a very low eccentricity of e = 0.0077-0.0032+0.0068, compatible with a circular orbit. We have detected the z'-band occultation at 3σ significance and measure it to be δFocc,z' = 352 ± 116 ppm, more than a factor of 2 smaller than previously published. The occultation at 1.19 μm is only marginally constrained at δFocc,NB1190 = 1711-726+745 ppm. Conclusions: We show that the detection of occultations in the visible range is within reach, even for 1 m class telescopes if a considerable number of individual events are observed. Our results suggest an oxygen-dominated atmosphere of WASP-19b, making the planet an interesting test case for oxygen-rich planets without temperature inversion. [less ▲]

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See detailComet C/2012 S1 (Ison)
Dello Russo, N.; Vervack, R. J.; Kawakita, H. et al

in Central Bureau Electronic Telegrams (2013), 3686

CBET 3686 available at Central Bureau for Astronomical Telegrams.

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See detailComet C/2012 S1 (Ison)
Opitom, Cyrielle ULg; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in Central Bureau Electronic Telegrams (2013), 3693

CBET 3693 available at Central Bureau for Astronomical Telegrams.

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See detailComet C/2012 S1 (Ison)
Crovisier, J.; Colom, P.; Biver, N. et al

in Central Bureau Electronic Telegrams (2013), 3711

CBET 3711 available at Central Bureau for Astronomical Telegrams.

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See detailComet C/2012 S1 (Ison)
Lisse, C. M.; Wolk, S. J.; Christian, D. J. et al

in Central Bureau Electronic Telegrams (2013), 3719

CBET 3719 available at Central Bureau for Astronomical Telegrams.

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See detailWASP-71b: a bloated hot Jupiter in an 2.9-day, prograde orbit around an evolved F8 star
Smith, A. M. S.; Anderson, D. R.; Bouchy, F. et al

in Astronomy and Astrophysics (2013), 552

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b ... [more ▼]

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b, is larger than Jupiter (1.46 +/- 0.13 RJup), but less dense (0.71 +/- 0.16 {\rho}Jup). We also report spectroscopic observations made during transit with the CORALIE spectrograph, which allow us to make a highly-significant detection of the Rossiter-McLaughlin effect. We determine the sky-projected angle between the stellar-spin and planetary-orbit axes to be {\lambda} = 20.1 +/- 9.7 degrees, i.e. the system is 'aligned', according to the widely-used alignment criteria that systems are regarded as misaligned only when {\lambda} is measured to be greater than 10 degrees with 3-{\sigma} confidence. WASP-71, with an effective temperature of 6059 +/- 98 K, therefore fits the previously observed pattern that only stars hotter than 6250 K are host to planets in misaligned orbits. We emphasise, however, that {\lambda} is merely the sky-projected obliquity angle; we are unable to determine whether the stellar-spin and planetary-orbit axes are misaligned along the line-of-sight. With a mass of 1.56 +/- 0.07 Msun, WASP-71 was previously hotter than 6250 K, and therefore might have been significantly misaligned in the past. If so, the planetary orbit has been realigned, presumably through tidal interactions with the cooling star's growing convective zone. [less ▲]

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See detailDiscovery of WASP-65b and WASP-75b: Two Hot Jupiters Without Highly Inflated Radii
Gómez Maqueo Chew, Y.; Faedi, F.; Pollacco, D. et al

in Astronomy and Astrophysics (2013)

We report the discovery of two transiting hot Jupiters, WASP-65b (Mpl = 1.55 ± 0.16 MJ; Rpl = 1.11 ± 0.06 RJ), and WASP-75b (Mpl = 1.07 ± 0.05 MJ; Rpl = 1.27 ± 0.05 RJ). They orbit their host star every ... [more ▼]

We report the discovery of two transiting hot Jupiters, WASP-65b (Mpl = 1.55 ± 0.16 MJ; Rpl = 1.11 ± 0.06 RJ), and WASP-75b (Mpl = 1.07 ± 0.05 MJ; Rpl = 1.27 ± 0.05 RJ). They orbit their host star every ~2.311, and ~2.484 days, respectively. The planet host WASP-65 is a G6 star (Teff = 5600 K, [Fe/H] = -0.07 ± 0.07, age ≳8 Gyr); WASP-75 is an F9 star (Teff = 6100 K, [Fe/H] = 0.07 ± 0.09, age ~ 3 Gyr). WASP-65b is one of the densest known exoplanets in the mass range 0.1 and 2.0 MJ (rhopl = 1.13 ± 0.08 rhoJ), a mass range where a large fraction of planets are found to be inflated with respect to theoretical planet models. WASP-65b is one of only a handful of planets with masses of ~1.5 MJ, a mass regime surprisingly underrepresented among the currently known hot Jupiters. The radius of WASP-75b is slightly inflated (≲10%) as compared to theoretical planet models with no core, and has a density similar to that of Saturn (rhopl = 0.52 ± 0.06 rhoJ). [less ▲]

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See detailHyper-volatiles in Comet C/2010 G2 (Hill)
Kawakita, Hideyo; Dello Russo, N.; Vervack, R. J. J. et al

in Bulletin of the American Astronomical Society (2013, October 01), 45

We performed high-dispersion near-infrared spectroscopic observations of comet C/2010 G2 (Hill) at 2.5 AU from the Sun using NIRSPEC (R ~ 2.5x10^4) at the Keck II telescope on UT 2012 Jan 9 and 10. The ... [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 ~ 2.5x10^4) at the Keck II telescope on UT 2012 Jan 9 and 10. The comet had been in outburst. Over the two nights of our observations, prominent emission lines of CH4 and C2H6 along with weaker emission lines of H2O, HCN, CH3OH and CO were detected. The gas production rate of CO was comparable to that of H2O. The mixing ratios of CO, HCN, CH4, C2H6, and CH3OH with respect to H2O are higher than those for normal comets by a factor of five or more. Hyper-volatile species such as CO and CH4 were enriched in the coma of comet Hill suggesting that the sublimation of these hyper-volatiles could sustain the outburst of the comet. Based on a comparison with optical observations, some fraction of water in the inner coma existed as icy grains. Those icy ice grains were likely ejected from nucleus by the sublimation of hyper-volatiles. [less ▲]

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See detailStudy of the Forbidden Oxygen Lines in Comets at Different Heliocentric and Nucleocentric Distances
Decock, Alice ULg; Rousselot, P.; Jehin, Emmanuel ULg et al

in Bulletin of the American Astronomical Society (2013, October 01), 45

Oxygen is an important element in the chemistry of the solar system objects given its abundance and its presence in many molecules including H2O 80% of cometary ices). The analysis of oxygen atoms in ... [more ▼]

Oxygen is an important element in the chemistry of the solar system objects given its abundance and its presence in many molecules including H2O 80% of cometary ices). The analysis of oxygen atoms in comets can provide information not only on the comets themselves but also on the solar system. These atoms have been analyzed using the 3 forbidden oxygen lines [OI] observed in emission in the optical region at 5577.339 Å (the green line), 6300.304 Å and 6363.776 Å (the red lines) (Swings, 1962). Our analysis is based on a sample of 12 comets of various origins. The observing material is made of 53 high signal-to-noise spectra obtained with the high-resolution UVES spectrograph at the ESO VLT from 2002 to 2012 (Manfroid et al, 2009). After noticing that the green line is blended with one C2 line, we built synthetic spectra of C2 for each observing circumstances and we subtracted its contribution to the cometary spectra in order to ensure the decontamination of the 5577 Å line. Then, we measured the intensity of the 3 [OI] lines at different heliocentric distances. By comparing the green to red lines ratio (G/R) with the Bhardwaj & Raghuram (2012) effective excitation rates, we found that H2O is the main parent molecule when the comet is observed at 1 au. When the comet is located beyond 2.5 au from the Sun, CO2 also contributes to the production of oxygen. Studying forbidden oxygen lines could be a new way to estimate the abundances of CO2 in comets, a very difficult task from the ground (Decock et al. 2013). In order to estimate the effect of the quenching on our results, we analyzed the evolution of the G/R ratio at different nucleocentric distances. For nearby comets, we divided the extended 2D spectrum into several zones in order to analyze the oxygen lines as close as possible to the nucleus (down to ~10 km for the closest comets). Their analysis will allow us to study the link of the oxygen lines with the nucleocentric distance. We found a clear variation of the G/R ratio close to the comet nucleus that is in agreement with a contribution from CO2 as predicted by Raghuram & Bhardwaj (2013). [less ▲]

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See detailA Search For 15NH2 Emission Lines In Comets
Rousselot, Philippe; Pirali, O.; Jehin, Emmanuel ULg et al

in Bulletin of the American Astronomical Society (2013, October 01), 45

The determination of nitrogen isotopic ratios in solar system objects is important for a good understanding of their origin. The measurements of [SUB]14[/SUB]N/[SUB]15[/SUB]N isotopic ratio done so far in ... [more ▼]

The determination of nitrogen isotopic ratios in solar system objects is important for a good understanding of their origin. The measurements of [SUB]14[/SUB]N/[SUB]15[/SUB]N isotopic ratio done so far in various solar system objects and molecules have revealed a great diversity (from 50 to 441), all of them, except Jupiter, being enriched in [SUB]15[/SUB]N compared to the protosolar nebula. Different explanations have been proposed to explain this enrichement. One of them suggests that these differences reflect the different interstellar N reservoirs from which N-bearing molecules are originating (Hily-Blant et al., 2013). These authors, from observations of H[SUB]13[/SUB]CN and HC[SUB]15[/SUB]N in two prestellar cores, suggest that the molecules carrying the nitrile- (-CN) functional group would be more enriched in [SUB]15[/SUB]N than the molecules carrying the amine (-NH) functional group. Comets are interesting targets to test this theory because they contain both HCN and NH[SUP]3[/SUP] molecules. So far the [SUB]14[/SUB]N/[SUB]15[/SUB]N ratio has only been measured in CN (Arpigny et al., 2003; Manfroid et al., 2009) and HCN (Bockelée-Morvan et al., 2005, 2008) in comets, leading for both species to [SUB]14[/SUB]N/[SUB]15[/SUB]N ≈ 150. Our work aimed at measuring the [SUB]14[/SUB]N/[SUB]15[/SUB]N isotopic ratio in NH[SUP]2[/SUP], which comes from NH[SUP]3[/SUP]. We have determined accurately the wavelengths of [SUB]15[/SUB]NH[SUP]2[/SUP] emission lines with the AILES beamline spectrometer at synchrotron SOLEIL by Fourier transform spectroscopy. The analysis of this spectrum has permitted to extract the [SUB]15[/SUB]NH[SUP]2[/SUP] emission lines wavelengths and to search for [SUB]15[/SUB]NH[SUP]2[/SUP] cometary emission lines. Thanks to a collection of spectra of 12 different comets obtained from 2002 to 2011 with the UVES spectrometer at the VLT ESO 8-m telescope (Manfroid et al., 2009), it has been possible to search for [SUB]15[/SUB]NH[SUP]2[/SUP] emission lines with a high sensitivity. We will present the results obtained from these data. Arpigny et al., Science, 301, 1522-1525, 2003 Bockelée-Morvan et al., in Comets II, ed. M. C. Festou, H. U. Keller, & H. A. Weaver (Tucson: Univ. Arizona Press), 391-423, 2005 Bockelée-Morvan et al., ApJ, 679, L49-L52, 2008 Hily-Blant et al., Icarus 223, 582-590, 2013 Manfroid et al., A&A, 503, 613-624, 2009 [less ▲]

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See detailThe May 4, 2013 Stellar Occultation by Pluto and Implications for Pluto's Atmosphere
Olkin, Catherine B.; Young, L. A.; Borncamp, D. et al

in Bulletin of the American Astronomical Society (2013, October 01), 45

On May 4 2013, Pluto passed in front of a 14 star and the shadow was well observed from multiple occultation groups. This paper presents results from the three light curves observed at Las Cumbres ... [more ▼]

On May 4 2013, Pluto passed in front of a 14 star and the shadow was well observed from multiple occultation groups. This paper presents results from the three light curves observed at Las Cumbres Observatory Global Telescope Network (LCOGT) from their Cerro Tololo site. The three LCOGT telescopes have 1.0 m apertures and used identical frame-transfer cameras. The cameras currently have a 2 second readout time therefore autonomous observations were scheduled with different exposure times to give good time resolution of the event. We will present results of this occultation and compare occultation results from 1988 to 2013 with volatile transport models. [less ▲]

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See detailComet dust profiles from PACS images obtained in the framework of the HSSO project
Opitom, Cyrielle ULg; Bockelée-Morvan, D.; Hutsemekers, Damien ULg et al

Poster (2013, October)

In the framework of the HssO project the Herschel PACS instrument acquired images of 7 comets between June 2010 and February 2013. Three of these comets have been imaged at several heliocentric distances ... [more ▼]

In the framework of the HssO project the Herschel PACS instrument acquired images of 7 comets between June 2010 and February 2013. Three of these comets have been imaged at several heliocentric distances allowing us to follow up the evolution of the dust coma . Radial profiles have been derived for each image. We measured flux densities at 70, 110 and 160 μm in order to determine the comet dust production rate. In some cases, after deconvolution by the instrumental PSF, we might have detected the nucleus signal in the central pixels. [less ▲]

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See detailThree irradiated and bloated hot Jupiters: WASP-76b, WASP-82b & WASP-90b
West, R. G.; Almenara, J.-M.; Anderson, D. R. et al

E-print/Working paper (2013)

We report three new transiting hot-Jupiter planets discovered from the WASP surveys combined with radial velocities from OHP/SOPHIE and Euler/CORALIE and photometry from Euler and TRAPPIST. All three ... [more ▼]

We report three new transiting hot-Jupiter planets discovered from the WASP surveys combined with radial velocities from OHP/SOPHIE and Euler/CORALIE and photometry from Euler and TRAPPIST. All three planets are inflated, with radii 1.7-1.8 Rjup. All orbit hot stars, F5-F7, and all three stars have evolved, post-MS radii (1.7-2.2 Rsun). Thus the three planets, with orbits of 1.8-3.9 d, are among the most irradiated planets known. This reinforces the correlation between inflated planets and stellar irradiation. [less ▲]

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See detailThree sub-Jupiter-mass planets: WASP-69b & WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary
Anderson, D. R.; Collier Cameron, A.; Delrez, Laetitia ULg et al

E-print/Working paper (2013)

We report the discovery of the transiting exoplanets WASP-69b, WASP-70Ab and WASP-84b, each of which orbits a bright star (V~10). WASP-69b is a bloated Saturn-mass planet (0.26 M$_{\rm Jup}$, 1.06 R$_{\rm ... [more ▼]

We report the discovery of the transiting exoplanets WASP-69b, WASP-70Ab and WASP-84b, each of which orbits a bright star (V~10). WASP-69b is a bloated Saturn-mass planet (0.26 M$_{\rm Jup}$, 1.06 R$_{\rm Jup}$) in a 3.868-d period around an active mid-K dwarf. We estimate a stellar age of 1 Gyr from both gyrochronological and age-activity relations, though an alternative gyrochronological relation suggests an age of 3 Gyr. ROSAT detected X-rays at a distance of 60$\pm$27 arcsec from WASP-69. If the star is the source then the planet could be undergoing mass-loss at a rate of ~10$^{12}$ g s$^{-1}$. This is 1-2 orders of magnitude higher than the evaporation rate estimated for HD 209458b and HD 189733b, both of which have exhibited anomalously-large Lyman-{\alpha} absorption during transit. WASP-70Ab is a sub-Jupiter-mass planet (0.59 M$_{\rm Jup}$, 1.16R$_{\rm Jup}$) in a 3.713-d orbit around the primary of a spatially-resolved G4+K3 binary, with a separation of 3.3 arcsec ($\geq$800 AU). We exploit the binary nature of the system to construct a H-R diagram, from which we estimate its age to be 9-10 Gyr. WASP-84b is a sub-Jupiter-mass planet (0.69 M$_{\rm Jup}$, 0.94 R$_{\rm Jup}$) in an 8.523-d orbit around an active early-K dwarf. Of the transiting planets discovered from the ground to date, WASP-84b has the third-longest period. From a combination of gyrochronological and age-activity relations we estimate the age of WASP-84 to be ~1 Gyr. For both the active stars WASP-69 and WASP-84 we find a modulation of the radial velocities with a period similar to the photometrically-determined stellar rotation period. We fit the residuals with a low-order harmonic series and subtract the best fit from the RVs prior to deriving the system parameters. In each case the solution is essentially unchanged, with much less than a 1-{\sigma} change to the planetary mass. We found... [less ▲]

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See detailTRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope)
Jehin, Emmanuel ULg; Gillon, Michaël ULg; Opitom, Cyrielle ULg et al

in EPSC Abstract 2013 (2013, September 13), 8

TRAPPIST 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 ... [more ▼]

TRAPPIST 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. We describe here the hardware and the goals of the project and give an overview of the comet production rates monitoring after three years of operations. [less ▲]

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