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 Publications of Michaël Gillon     Results 1-20 of 356. 1 2 3 4 5 6 7 8 9 10   Three hot-Jupiters on the upper edge of the mass-radius distribution: WASP-177, WASP-181, and WASP-183Turner, Oliver D.; Anderson, D. R.; Barkaoui, K. et alin Monthly Notices of the Royal Astronomical Society (2019), 485We present the discovery of three transiting planets from the WASP survey, two hot-Jupiters: WASP-177 b (˜0.5 M[SUB]Jup[/SUB], ˜1.6 R[SUB]Jup[/SUB]) in a 3.07-d orbit of a V = 12.6 K2 star, WASP-183 b (˜0 ... [more ▼]We present the discovery of three transiting planets from the WASP survey, two hot-Jupiters: WASP-177 b (˜0.5 M[SUB]Jup[/SUB], ˜1.6 R[SUB]Jup[/SUB]) in a 3.07-d orbit of a V = 12.6 K2 star, WASP-183 b (˜0.5 M[SUB]Jup[/SUB], ˜1.5 R[SUB]Jup[/SUB]) in a 4.11-d orbit of a V = 12.8 G9/K0 star; and one hot-Saturn planet WASP-181 b (˜0.3 M[SUB]Jup[/SUB], ˜1.2 R[SUB]Jup[/SUB]) in a 4.52-d orbit of a V = 12.9 G2 star. Each planet is close to the upper bound of mass-radius space and has a scaled semimajor axis, a/R[SUB]*[/SUB], between 9.6 and 12.1. These lie in the transition between systems that tend to be in orbits that are well aligned with their host-star's spin and those that show a higher dispersion. [less ▲]Detailed reference viewed: 18 (2 ULiège) Qatar Exoplanet Survey: Qatar-8b, 9b, and 10b—A Hot Saturn and Two Hot JupitersAlsubai, Khalid; Tsvetanov, Zlatan I.; Pyrzas, Stylianos et alin Astronomical Journal (2019), 157(6), 10In this paper we present three new extrasolar planets from the Qatar Exoplanet Survey. Qatar-8b is a hot Saturn, with M [SUB]P[/SUB] = 0.37 M [SUB]J[/SUB] and R [SUB]P[/SUB] = 1.3 R [SUB]J[/SUB], orbiting ... [more ▼]In this paper we present three new extrasolar planets from the Qatar Exoplanet Survey. Qatar-8b is a hot Saturn, with M [SUB]P[/SUB] = 0.37 M [SUB]J[/SUB] and R [SUB]P[/SUB] = 1.3 R [SUB]J[/SUB], orbiting a solar-like star every P [SUB]orb[/SUB] = 3.7 days. Qatar-9b is a hot Jupiter with a mass of M [SUB]P[/SUB] = 1.2 M [SUB]J[/SUB] and a radius of R [SUB]P[/SUB] = 1 R [SUB]J[/SUB], in an orbit of P [SUB]orb[/SUB] = 1.5 days around a low mass, M [SUB]⋆[/SUB] = 0.7 M [SUB]⊙[/SUB], mid-K main-sequence star. Finally, Qatar-10b is a hot, T [SUB]eq[/SUB] ∼ 2000 K, sub-Jupiter mass planet, M [SUB]P[/SUB] = 0.7 M [SUB]J[/SUB], with a radius of R [SUB]P[/SUB] = 1.54 R [SUB]J[/SUB] and an orbital period of P [SUB]orb[/SUB] = 1.6 days, placing it on the edge of the sub-Jupiter desert. [less ▲]Detailed reference viewed: 17 (2 ULiège) Lower atmosphere and pressure evolution on Pluto from ground-based stellar occultations, 1988-2016Meza, E.; Sicardy, B.; Assafin, M. et alin Astronomy and Astrophysics (2019), 625(A42), 21Context. The tenuous nitrogen (N[SUB]2[/SUB]) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New ... [more ▼]Context. The tenuous nitrogen (N[SUB]2[/SUB]) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New Horizons spacecraft.
Aims: The main goals of this study are (i) to construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) to constrain the structure of the lower atmosphere using a central flash observed in 2015.
Methods: Eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between altitude levels of 5 and 380 km (i.e. pressures from 10 μbar to 10 nbar).
Results: (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N[SUB]2[/SUB] ice are derived. (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia; and/or (b) hazes with tangential optical depth of 0.3 are present at 4-7 km altitude levels; and/or (c) the nominal REX density values are overestimated by an implausibly large factor of 20%; and/or (d) higher terrains block part of the flash in the Charon facing hemisphere. [less ▲]Detailed reference viewed: 24 (2 ULiège) High resolution optical spectroscopy of the N2-rich comet C/2016 R2 (PanSTARRS)Opitom, C.; Hutsemekers, Damien ; Jehin, Emmanuel et alin Astronomy and Astrophysics (2019), 624Context. Early observations of comet C/2016 R2 (PanSTARRS) have shown that the composition of this comet is very peculiar. Radio observations have revealed a CO-rich and HCN-poor comet and an optical coma ... [more ▼]Context. Early observations of comet C/2016 R2 (PanSTARRS) have shown that the composition of this comet is very peculiar. Radio observations have revealed a CO-rich and HCN-poor comet and an optical coma dominated by strong emission bands of CO[SUP]+[/SUP] and, more surprisingly, N[SUB]2[/SUB][SUP]+[/SUP].
Aims: The strong detection of N[SUB]2[/SUB][SUP]+[/SUP] in the coma of C/2016 R2 provided an ideal opportunity to measure the [SUP]14[/SUP]N/[SUP]15[/SUP]N isotopic ratio directly from N[SUB]2[/SUB][SUP]+[/SUP] for the first time, and to estimate the N[SUB]2[/SUB]/CO ratio, which is an important diagnostic to constrain formation models of planetesimals, in addition to the more general study of coma composition.
Methods: We obtained high resolution spectra of the comet in February 2018 when it was at 2.8 au from the Sun. We used the UVES spectrograph of the European Southern Observatory Very Large Telescope, complemented with narrowband images obtained with the TRAPPIST telescopes.
Results: We detect strong emissions from the N[SUB]2[/SUB][SUP]+[/SUP] and CO[SUP]+[/SUP] ions, but also CO[SUB]2[/SUB][SUP]+[/SUP], emission lines from the CH radical, and much fainter emissions of the CN, C[SUB]2[/SUB], and C[SUB]3[/SUB] radicals that were not detected in previous observations of this comet. We do not detect OH or H[SUB]2[/SUB]O[SUP]+[/SUP], and we derive an upper limit of the H[SUB]2[/SUB]O[SUP]+[/SUP]/CO[SUP]+[/SUP] ratio of 0.4, implying that the comet has a low water abundance. We measure a N[SUB]2[/SUB][SUP]+[/SUP]/CO[SUP]+[/SUP] ratio of 0.06 ± 0.01. The non-detection of NH[SUB]2[/SUB] indicates that most of the nitrogen content of the comet is in N[SUB]2[/SUB]. Together with the high N[SUB]2[/SUB][SUP]+[/SUP]/CO[SUP]+[/SUP] ratio, this could indicate a low formation temperature of the comet or that the comet is a fragment of a large differentiated Kuiper Belt object. The CO[SUB]2[/SUB][SUP]+[/SUP]/CO[SUP]+[/SUP] ratio is 1.1 ± 0.3. We do not detect [SUP]14[/SUP]N[SUP]15[/SUP]N[SUP]+[/SUP] lines and can only put a lower limit on the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratio (measured from N[SUB]2[/SUB][SUP]+[/SUP]) of about 100, which is compatible with measurements of the same isotopic ratio for NH[SUB]2[/SUB] and CN in other comets. Finally, in addition to the [OI] and [CI] forbidden lines, we detect for the first time the forbidden nitrogen lines [NI] doublet at 519.79 and 520.03 nm in the coma of a comet. [less ▲]Detailed reference viewed: 34 (14 ULiège) WASP-190b: Tomographic Discovery of a Transiting Hot JupiterTemple, L. Y.; Hellier, C.; Almleaky, Y. et alin Astronomical Journal (2019), 157We report the discovery of WASP-190b, an exoplanet on a 5.37 day orbit around a mildly evolved F6 IV-V star with V = 11.7, {T}[SUB]eff[/SUB]} = 6400 ± 100 K, M [SUB]*[/SUB] = 1.35 ± 0.05 M [SUB]⊙[/SUB ... [more ▼]We report the discovery of WASP-190b, an exoplanet on a 5.37 day orbit around a mildly evolved F6 IV-V star with V = 11.7, {T}[SUB]eff[/SUB]} = 6400 ± 100 K, M [SUB]*[/SUB] = 1.35 ± 0.05 M [SUB]⊙[/SUB], and R [SUB]*[/SUB] = 1.6 ± 0.1 R [SUB]⊙[/SUB]. The planet has a radius of R [SUB]P[/SUB] = 1.15 ± 0.09 R [SUB]Jup[/SUB] and a mass of M [SUB]P[/SUB] = 1.0 ± 0.1 M [SUB]Jup[/SUB], making it a mildly inflated hot Jupiter. It is the first hot Jupiter confirmed via Doppler tomography with an orbital period of >5 days. The orbit is also marginally misaligned with respect to the stellar rotation, with λ = 21° ± 6° measured using Doppler tomography. [less ▲]Detailed reference viewed: 14 (1 ULiège) Discovery of three new transiting hot Jupiters: WASP-161 b, WASP-163 b and WASP-170 bBarkaoui, K.; Burdanov, Artem ; Hellier, C. et alin Astronomical Journal (2019), 157(2), We present the discovery by the WASP-South transit survey of three new transiting hot Jupiters, WASP-161 b, WASP-163 b and WASP-170 b. Follow-up radial velocities obtained with the Euler/CORALIE ... [more ▼]We present the discovery by the WASP-South transit survey of three new transiting hot Jupiters, WASP-161 b, WASP-163 b and WASP-170 b. Follow-up radial velocities obtained with the Euler/CORALIE spectrograph and high-precision transit light curves obtained with the TRAPPIST-North, TRAPPIST-South, SPECULOOS-South, NITES, and Euler telescopes have enabled us to determine the masses and radii for these transiting exoplanets. WASP-161\,b completes an orbit around its $V=11.1$ F6V-type host star in 5.406 days, and has a mass and radius of $2.5\pm 0.2$$M_{Jup}$ and $1.14\pm 0.06$ $R_{Jup}$ respectively. WASP-163\,b has an orbital period of 1.609 days, a mass of $1.9\pm0.2$ $M_{Jup}$, and a radius of $1.2\pm0.1$ $R_{Jup}$. Its host star is a $V=12.5$ G8-type dwarf. WASP-170\,b is on a 2.344 days orbit around a G1V-type star of magnitude $V=12.8$. It has a mass of $1.7\pm0.2$ $M_{Jup}$ and a radius of $1.14\pm0.09$ $R_{Jup}$. Given their irradiations ($\sim10^9$ erg.s$^{-1}$.cm$^{-2}$) and masses, the three new planets sizes are in good agreement with classical structure models of irradiated giant planets. [less ▲]Detailed reference viewed: 32 (7 ULiège) L'observatoire SPECULOOS-SudJehin, Emmanuel ; Gillon, Michaël in Ciel (Le) (2019), (Février), 75-90Après quatre années de préparation et deux années de travail sur le site, l’observatoire SPECULOOS Sud a été installé avec succès dans l’enceinte de l’observatoire européen austral (ESO) de Paranal. C’est ... [more ▼]Après quatre années de préparation et deux années de travail sur le site, l’observatoire SPECULOOS Sud a été installé avec succès dans l’enceinte de l’observatoire européen austral (ESO) de Paranal. C’est la veille de la Saint Nicolas, une date de circonstance, que l’observatoire a été inauguré en présence des autorités de l’université de Liège et de l’ensemble de l’équipe SPECULOOS1 rassemblant des chercheurs de nombreux pays et dirigée à Liège par le chercheur liégeois Michaël Gillon. Après cette « First Light » symbolique pour montrer que les télescopes sont opérationnels, ces nouveaux chasseurs d’exoplanètes débuteront officiellement leurs observations scientifiques en janvier 2019. [less ▲]Detailed reference viewed: 16 (2 ULiège) New transiting hot Jupiters discovered by WASP-South, Euler/CORALIE, and TRAPPIST-SouthHellier, Coel; Anderson, D. R.; Bouchy, F. et alin Monthly Notices of the Royal Astronomical Society (2019), 482We report the discovery of eight hot-Jupiter exoplanets from the WASP-South transit survey. WASP-144b has a mass of 0.44 M[SUB]Jup[/SUB], a radius of 0.85 R[SUB]Jup[/SUB], and is in a 2.27-d orbit around ... [more ▼]We report the discovery of eight hot-Jupiter exoplanets from the WASP-South transit survey. WASP-144b has a mass of 0.44 M[SUB]Jup[/SUB], a radius of 0.85 R[SUB]Jup[/SUB], and is in a 2.27-d orbit around a V = 12.9, K2 star which shows a 21-d rotational modulation. WASP-145Ab is a 0.89 M[SUB]Jup[/SUB] planet in a 1.77-d orbit with a grazing transit. The host is a V = 11.5, K2 star with a companion 5 arcsec away and 1.4 mag fainter. WASP-158b is a relatively massive planet at 2.8 M[SUB]Jup[/SUB] with a radius of 1.1 R[SUB]Jup[/SUB] and a 3.66-d orbit. It transits a V = 12.1, F6 star. WASP-159b is a bloated hot Jupiter (1.4 R[SUB]Jup[/SUB] and 0.55 M[SUB]Jup[/SUB]) in a 3.8-d orbit around a V = 12.9, F9 star. WASP-162b is a massive planet in a relatively long and highly eccentric orbit (5.2 M[SUB]Jup[/SUB], P = 9.6 d, e = 0.43). It transits a V = 12.2, K0 star. WASP-168b is a bloated hot Jupiter (0.42 M[SUB]Jup[/SUB]; 1.5 R[SUB]Jup[/SUB]) in a 4.15-d orbit with a grazing transit. The host is a V = 12.1, F9 star. WASP-172b is a bloated hot Jupiter (0.5 M[SUB]Jup[/SUB]; 1.6 R[SUB]Jup[/SUB]) in a 5.48-d orbit around a V = 11.0, F1 star. WASP-173Ab is a massive planet (3.7 M[SUB]Jup[/SUB]) with a 1.2 R[SUB]Jup[/SUB] radius in a circular orbit with a period of 1.39 d. The host is a V = 11.3, G3 star, being the brighter component of the double-star system WDS23366 - 3437, with a companion 6 arcsec away and 0.8 mag fainter. One of the two stars shows a rotational modulation of 7.9 d. [less ▲]Detailed reference viewed: 18 (2 ULiège) The homogeneous internal structure of CM-like asteroid (41) DaphneCarry, B.; Vachier, F.; Berthier, J. et alin Astronomy and Astrophysics (2019), 623(A132), Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been ... [more ▼]Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been predicted to be homogeneous, based on their compositional similarity as inferred from spectroscopy (Vernazza et al., 2016, AJ 152, 154) and numerical modeling of their early thermal evolution (Bland & Travis, 2017, Sci. Adv. 3, e1602514). Aims. Here we aim to test this hypothesis by deriving the density of the CM-like asteroid (41) Daphne from detailed modeling of its shape and the orbit of its small satellite. Methods. We observed Daphne and its satellite within our imaging survey with the Very Large Telescope extreme adaptive-optics SPHERE/ZIMPOL camera (ID 199.C-0074, PI P. Vernazza) and complemented this data set with earlier Keck/NIRC2 and VLT/NACO observations. We analyzed the dynamics of the satellite with our Genoid meta-heuristic algorithm. Combining our high-angular resolution images with optical lightcurves and stellar occultations, we determine the spin period, orientation, and 3-D shape, using our ADAM shape modeling algorithm. Results. The satellite orbits Daphne on an equatorial, quasi-circular, prograde orbit, like the satellites of many other large main-belt asteroids. The shape model of Daphne reveals several large flat areas that could be large impact craters. The mass determined from this orbit combined with the volume computed from the shape model implies a density for Daphne of 1.77+/-0.26 g/cm3 (3 {\sigma}). This density is consistent with a primordial CM-like homogeneous internal structure with some level of macroporosity (~17%). Conclusions. Based on our analysis of the density of Daphne and 75 other Ch/Cgh-type asteroids gathered from the literature, we conclude that the primordial internal structure of the CM parent bodies was homogeneous. [less ▲]Detailed reference viewed: 15 (4 ULiège) The SPECULOOS Southern Observatory Begins its Hunt for Rocky PlanetsJehin, Emmanuel ; Gillon, Michaël ; Queloz, D. et alin Messenger (2018), 174The SPECULOOS Southern Observatory (SSO), a new facility of four 1- metre robotic telescopes, began scientific operations at Cerro Paranal on 1 January 2019. The main goal of the SPECULOOS project is to ... [more ▼]The SPECULOOS Southern Observatory (SSO), a new facility of four 1- metre robotic telescopes, began scientific operations at Cerro Paranal on 1 January 2019. The main goal of the SPECULOOS project is to explore approximately 1000 of the smallest (≤ 0.15 R[SUB]⊙[/SUB]), brightest (K[SUB]mag[/SUB] ≤ 12.5), and nearest (d ≤ 40 pc) very low mass stars and brown dwarfs. It aims to discover transiting temperate terrestrial planets well-suited for detailed atmospheric characterisation with future giant telescopes like ESO’s Extremely Large Telescope (ELT) and the NASA James Webb Telescope (JWST). The SSO is the core facility of SPECULOOS. The exquisite astronomical conditions at Cerro Paranal will enable SPECULOOS to detect exoplanets as small as Mars. Here, we briefly describe SPECULOOS, and present the features and performance of the SSO facility. [less ▲]Detailed reference viewed: 13 (1 ULiège) The discovery of WASP-134b, WASP-134c, WASP-137b, WASP-143b and WASP-146b: three hot Jupiters and a pair of warm Jupiters orbiting Solar-type starsAnderson, D. R.; Bouchy, F.; Brown, D. J. A. et alE-print/Working paper (2018)We report the discovery by WASP of five planets orbiting moderately bright ($V$ = 11.0-12.9) Solar-type stars. WASP-137b, WASP-143b and WASP-146b are typical hot Jupiters in orbits of 3-4 d and with ... [more ▼]We report the discovery by WASP of five planets orbiting moderately bright ($V$ = 11.0-12.9) Solar-type stars. WASP-137b, WASP-143b and WASP-146b are typical hot Jupiters in orbits of 3-4 d and with masses in the range 0.68--1.11 $M_{\rm Jup}$. WASP-134 is a metal-rich ([Fe/H] = +0.40 $\pm$ 0.07]) G4 star orbited by two warm Jupiters: WASP-134b ($M_{\rm pl}$ = 1.41 $M_{\rm Jup}$; $P = 10.1$ d; $e = 0.15 \pm 0.01$; $T_{\rm eql}$ = 950 K) and WASP-134c ($M_{\rm pl} \sin i$ = 0.70 $M_{\rm Jup}$; $P = 70.0$ d; $e = 0.17 \pm 0.09$; $T_{\rm eql}$ = 500 K). From observations of the Rossiter-McLaughlin effect of WASP-134b, we find its orbit to be misaligned with the spin of its star ($\lambda = -44 \pm 10^\circ$). WASP-134 is a rare example of a system with a short-period giant planet and a nearby giant companion. In-situ formation or disc migration seem more likely explanations for such systems than does high-eccentricity migration. [less ▲]Detailed reference viewed: 12 (1 ULiège) Space-based infrared interferometry to study exoplanetary atmospheresDefrere, Denis ; Léger, A.; Absil, Olivier et alin Experimental Astronomy (2018), 46(3), 543-560The quest for other habitable worlds and the search for life among them are major goals of modern astronomy. One way to make progress towards these goals is to obtain high-quality spectra of a large ... [more ▼]The quest for other habitable worlds and the search for life among them are major goals of modern astronomy. One way to make progress towards these goals is to obtain high-quality spectra of a large number of exoplanets over a broad range of wavelengths. While concepts currently investigated in the United States are focused on visible/NIR wavelengths, where the planets are probed in reflected light, a compelling alternative to characterize planetary atmospheres is the mid-infrared waveband (5-20um). Indeed, mid-infrared observations provide key information on the presence of an atmosphere, the surface conditions (e.g., temperature, pressure, habitability), and the atmospheric composition in important species such as H2O, CO2, O3, CH4, and N2O. This information is essential to investigate the potential habitability of exoplanets and to make progress towards the search for life in the universe. Obtaining high-quality mid-infrared spectra of exoplanets from the ground is however extremely challenging due to the overwhelming brightness and turbulence of Earth's atmosphere. In this paper, we present a concept of space-based mid-infrared interferometer that can tackle this observing challenge and discuss the main technological developments required to launch such a sophisticated instrument. [less ▲]Detailed reference viewed: 89 (11 ULiège) Monitoring of the activity and composition of comets 41P/Tuttle-Giacobini-Kresak and 45P/Honda-Mrkos-PajdusakovaMoulane, Y.; Jehin, Emmanuel ; Opitom, C. et alin Astronomy and Astrophysics (2018), 619We report on photometry and imaging of the Jupiter Family Comets 41P/Tuttle-Giacobini-Kresak and 45P/Honda-Mrkos-Pajdusakova with the TRAPPIST-North telescope. We observed 41P on 34 nights from February ... [more ▼]We report on photometry and imaging of the Jupiter Family Comets 41P/Tuttle-Giacobini-Kresak and 45P/Honda-Mrkos-Pajdusakova with the TRAPPIST-North telescope. We observed 41P on 34 nights from February 16, 2017 to July 27, 2017 pre- and post-perihelion (r$_h$=1.04 au), while we collected data for comet 45P from February 10 to March 30 after perihelion (r$_h$=0.53 au). We computed the production rates of the daughter species OH, NH, CN, C$_3$ and C$_2$ and we measured the dust proxy, Af$\rho$, for both comets. The peak of water production rate of 41P was (3.46$\pm$0.20)$\times$10$^{27}$ molecules/s on April 3, 2017 when the comet was at 1.05 au from the Sun. We have shown that the activity of 41P is decreasing by about 30% to 40% from one apparition to the next. We measured a mean water production rate for 45P of (1.43$\pm$0.62)$\times$10$^{27}$ molecules/s during a month after perihelion. Our results show that these Jupiter Family Comets had low gas and dust activity and no outburst was detected. Relative abundances, expressed as ratios of production rates and Af$\rho$ parameter with respect to OH and to CN, were compared to those measured in other comets. We found that 41P and 45P have a typical composition in term of carbon bearing species. The study of coma features exhibited by the CN gas species allowed the measurement of the rotation period of 41P, showing a surprisingly large increase of the rotation period from (30$\pm$5) hrs at the end of March to (50$\pm$10) hrs at the end of April, 2017 in agreement with recent observations by other teams. [less ▲]Detailed reference viewed: 32 (5 ULiège) Activity induced variation in spin-orbit angles as derived from Rossiter-McLaughlin measurementsOshagh, M.; Triaud, A. H. M. J.; Burdanov, Artem et alin Astronomy and Astrophysics (2018), 619(150), One of the most powerful methods used to estimate sky-projected spin-orbit angles of exoplanetary systems is through a spectroscopic transit observation known as the Rossiter-McLaughlin (RM) effect. So ... [more ▼]One of the most powerful methods used to estimate sky-projected spin-orbit angles of exoplanetary systems is through a spectroscopic transit observation known as the Rossiter-McLaughlin (RM) effect. So far mostly single RM observations have been used to estimate the spin-orbit angle, and thus there have been no studies regarding the variation of estimated spin-orbit angle from transit to transit. Stellar activity can alter the shape of photometric transit light curves and in a similar way they can deform the RM signal. In this paper we discuss several RM observations, obtained using the HARPS spectrograph, of known transiting planets that all transit extremely active stars, and by analyzing them individually we assess the variation in the estimated spin-orbit angle. Our results reveal that the estimated spin-orbit angle can vary significantly (up to 42 degrees) from transit to transit, due to variation in the configuration of stellar active regions over different nights. This finding is almost two times larger than the expected variation predicted from simulations. We could not identify any meaningful correlation between the variation of estimated spin-orbit angles and the stellar magnetic activity indicators. We also investigated two possible approaches to mitigate the stellar activity influence on RM observations. The first strategy was based on obtaining several RM observations and folding them to reduce the stellar activity noise. Our results demonstrated that this is a feasible and robust way to overcome this issue. The second approach is based on acquiring simultaneous high-precision short-cadence photometric transit light curves using TRAPPIST/SPECULOOS telescopes, which provide more information about the stellar active region's properties and allow a better RM modeling. [less ▲]Detailed reference viewed: 17 (1 ULiège) The 0.8-4.5$\mu$m broadband transmission spectra of TRAPPIST-1 planetsDucrot, Elsa ; Sestovic, M.; Morris, B. M. et alin Astronomical Journal (2018), 156The TRAPPIST-1 planetary system represents an exceptional opportunity for the atmospheric characterization of temperate terrestrial exoplanets with the upcoming James Webb Space Telescope (JWST ... [more ▼]The TRAPPIST-1 planetary system represents an exceptional opportunity for the atmospheric characterization of temperate terrestrial exoplanets with the upcoming James Webb Space Telescope (JWST). Assessing the potential impact of stellar contamination on the planets' transit transmission spectra is an essential precursor step to this characterization. Planetary transits themselves can be used to scan the stellar photosphere and to constrain its heterogeneity through transit depth variations in time and wavelength. In this context, we present our analysis of 169 transits observed in the optical from space with K2 and from the ground with the SPECULOOS and Liverpool telescopes. Combining our measured transit depths with literature results gathered in the mid/near-IR with Spitzer/IRAC and HST/WFC3, we construct the broadband transmission spectra of the TRAPPIST-1 planets over the 0.8-4.5 $\mu$m spectral range. While planets b, d, and f spectra show some structures at the 200-300ppm level, the four others are globally flat. Even if we cannot discard their instrumental origins, two scenarios seem to be favored by the data: a stellar photosphere dominated by a few high-latitude giant (cold) spots, or, alternatively, by a few small and hot (3500-4000K) faculae. In both cases, the stellar contamination of the transit transmission spectra is expected to be less dramatic than predicted in recent papers. Nevertheless, based on our results, stellar contamination can still be of comparable or greater order than planetary atmospheric signals at certain wavelengths. Understanding and correcting the effects of stellar heterogeneity therefore appears essential to prepare the exploration of TRAPPIST-1's with JWST. [less ▲]Detailed reference viewed: 67 (23 ULiège) Discovery of WASP-174b: Doppler tomography of a near-grazing transitTemple, L. Y.; Hellier, C.; Almleaky, Y. et alin Monthly Notices of the Royal Astronomical Society (2018), 480We report the discovery and tomographic detection of WASP-174b, a planet with a near-grazing transit on a 4.23-d orbit around a V= 11.9, F6V star with [Fe/H] = 0.09 ± 0.09. The planet is in a moderately ... [more ▼]We report the discovery and tomographic detection of WASP-174b, a planet with a near-grazing transit on a 4.23-d orbit around a V= 11.9, F6V star with [Fe/H] = 0.09 ± 0.09. The planet is in a moderately misaligned orbit with a sky-projected spin-orbit angle of λ = 31° ± 1°. This is in agreement with the known tendency for orbits around hotter stars to be misaligned. Owing to the grazing transit, the planet's radius is uncertain with a possible range of 0.8-1.8 R[SUB]Jup[/SUB]. The planet's mass has an upper limit of 1.3 M[SUB]Jup[/SUB]. WASP-174 is the faintest hot-Jupiter system so far confirmed by tomographic means. [less ▲]Detailed reference viewed: 25 (3 ULiège) WASP-166b: a bloated super-Neptune transiting a V = 9 starHellier, Coel; Anderson, D. R.; Triaud, A. H. M. J. et alE-print/Working paper (2018)We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 Mjup and a bloated radius of 0.63 Rjup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar ... [more ▼]We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 Mjup and a bloated radius of 0.63 Rjup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar rotation (lambda = -3 +/- 5 degrees). WASP-166b appears to be a rare object within the `Neptune desert'. The planet's low surface gravity and bright host star make it a promising target for atmospheric characterisation. There are variations in the radial-velocity measurements that might result from stellar magnetic activity. [less ▲]Detailed reference viewed: 12 (1 ULiège) WASP-190b: Tomographic discovery of a transiting hot JupiterTemple, L. Y.; Hellier, C.; Anderson, D. R. et alE-print/Working paper (2018)We report the discovery of WASP-190b, an exoplanet on a 5.37-day orbit around an inflated F6 IV-V star with T_eff = 6400 $\pm$ 100 K, M$_{*}$ = 1.35 $\pm$ 0.05 M_sun and R$_{*}$ = 1.6 $\pm$ 0.1 R_sun. The ... [more ▼]We report the discovery of WASP-190b, an exoplanet on a 5.37-day orbit around an inflated F6 IV-V star with T_eff = 6400 $\pm$ 100 K, M$_{*}$ = 1.35 $\pm$ 0.05 M_sun and R$_{*}$ = 1.6 $\pm$ 0.1 R_sun. The planet has a radius of R_p = 1.15 $\pm$ 0.09 R_Jup and a mass of M_p = 1.0 $\pm$ 0.1 M_Jup, making it a mildly inflated hot Jupiter. The orbit is also marginally misaligned with respect to the stellar rotation, with $\lambda$ = 21 $\pm$ 6$^{\circ}$ measured using Doppler tomography. We compare a Rossiter-McLaughlin analysis (involving radial velocity measurements) with the Doppler tomography method, and find that the latter provides a better constraint on $vsini_{*}$ and $\lambda$. [less ▲]Detailed reference viewed: 12 (2 ULiège) WASP-147b, 160Bb, 164b and 165b: two hot Saturns and two Jupiters, including two planets with metal-rich hostsLendl, M.; Anderson, D. R.; Bonfanti, Andrea et alin Monthly Notices of the Royal Astronomical Society (2018)We report the discovery of four transiting hot Jupiters, WASP-147, WASP-160B, WASP-164 and WASP-165 from the WASP survey. WASP-147b is a near Saturn-mass (M[SUB]P[/SUB] = 0.28M[SUB]J[/SUB]) object with a ... [more ▼]We report the discovery of four transiting hot Jupiters, WASP-147, WASP-160B, WASP-164 and WASP-165 from the WASP survey. WASP-147b is a near Saturn-mass (M[SUB]P[/SUB] = 0.28M[SUB]J[/SUB]) object with a radius of 1.11 R[SUB]J[/SUB] orbiting a G4 star with a period of 4.6 d. WASP-160Bb has a mass and radius (M[SUB]p[/SUB] = 0.28 M[SUB]J[/SUB], R[SUB]p[/SUB] = 1.09 R[SUB]J[/SUB]) near-identical to WASP-147b, but is less irradiated, orbiting a metal-rich ([Fe/H][SUB]*[/SUB] = 0.27) K0 star with a period of 3.8 d. WASP-160B is part of a near equal-mass visual binary with an on-sky separation of 28.5 arcsec. WASP-164b is a more massive (M[SUB]P[/SUB] = 2.13 M[SUB]J[/SUB], R[SUB]p[/SUB] = 1.13 R[SUB]J[/SUB]) hot Jupiter, orbiting a G2 star on a close-in (P = 1.8 d), but tidally stable orbit. WASP-165b is a classical (M[SUB]p[/SUB] = 0.66 M[SUB]J[/SUB], R[SUB]P[/SUB] = 1.26 R[SUB]J[/SUB]) hot Jupiter in a 3.5 d period orbit around a metal-rich ([Fe/H][SUB]*[/SUB] = 0.33) star. WASP-147b and WASP-160Bb are promising targets for atmospheric characterization through transmission spectroscopy, while WASP-164b presents a good target for emission spectroscopy. [less ▲]Detailed reference viewed: 18 (3 ULiège) On the dust properties and dynamical evolution of the near- Earth Jupiter family comet 41P/Tuttle-Giacobini-KresakPozuelos Romero, Francisco José ; Jehin, Emmanuel ; Moulane, Youssef et alPoster (2018, September 01)We present a study of the evolution of the dust environment of the near-Earth Jupiter family comet 41P/Tuttle-Giacobini-Kresak, based on observational data obtained using TRAPPIST telescopes from January ... [more ▼]We present a study of the evolution of the dust environment of the near-Earth Jupiter family comet 41P/Tuttle-Giacobini-Kresak, based on observational data obtained using TRAPPIST telescopes from January to July, 2017. In addition, we performed numerical simulations to constrain its origin and dynamical nature. Along this work we compared our results with those obtained for 67P/Churyumov-Gerasimenko. These results have been recently accepted for publication in Astronomy & Astrophysics. [less ▲]Detailed reference viewed: 10 (2 ULiège)