[less ▲]Detailed reference viewed: 31 (2 ULiège) Trappist Lightcurves of Main-Belt Asteroids 31 Euphrosyne, 41 Daphne and 89 JuliaFerrais, Marin ; Jehin, Emmanuel ; Manfroid, Jean et alin Minor Planet Bulletin (2019), 46Densely sampled lightcurves of three large main-belt asteroids were obtained with the TRAPPIST-South (TS) and TRAPPIST-North (TN) telescopes from 2017 September to 2018 July. We found their synodic ... [more ▼]Densely sampled lightcurves of three large main-belt asteroids were obtained with the TRAPPIST-South (TS) and TRAPPIST-North (TN) telescopes from 2017 September to 2018 July. We found their synodic rotation periods and amplitudes to be: 31 Euphrosyne, 5.5312 ± 0.0007 h and 0.07 mag; 41 Daphne, 5.9912 ± 0.0028 h and 0.18 mag; and 89 Julia, 11.3844 ± 0.0002 h and 0.19 mag. All data have been submitted to the ALCDEF database. [less ▲]Detailed reference viewed: 66 (6 ULiège) A super-Earth and two sub-Neptunes transiting the nearby and quiet M dwarf TOI-270Günther, Maximilian N.; Pozuelos Romero, Francisco José ; Dittmann, Jason A. et alin Nature Astronomy (2019)One of the primary goals of exoplanetary science is to detect small, temperate planets passing (transiting) in front of bright and quiet host stars. This enables the characterization of planetary sizes ... [more ▼]One of the primary goals of exoplanetary science is to detect small, temperate planets passing (transiting) in front of bright and quiet host stars. This enables the characterization of planetary sizes, orbits, bulk compositions, atmospheres and formation histories. These studies are facilitated by small and cool M dwarf host stars. Here we report the Transiting Exoplanet Survey Satellite (TESS)[SUP]1[/SUP] discovery of three small planets transiting one of the nearest and brightest M dwarf hosts observed to date, TOI-270 (TIC 259377017, with K-magnitude 8.3, and 22.5 parsecs away from Earth). The M3V-type star is transited by the super-Earth-sized planet TOI-270 b (1.247[SUB]-0.083[/SUB][SUP]+0.089[/SUP]R[SUB]⊕[/SUB]) and the sub- Neptune-sized planets TOI-270 c (2.42 ± 0.13 R[SUB]⊕[/SUB]) and TOI-270 d (2.13 ± 0.12 R[SUB]⊕[/SUB]). The planets orbit close to a mean-motion resonant chain, with periods (3.36 days, 5.66 days and 11.38 days, respectively) near ratios of small integers (5:3 and 2:1). TOI-270 is a prime target for future studies because (1) its near-resonance allows the detection of transit timing variations, enabling precise mass measurements and dynamical studies; (2) its brightness enables independent radial-velocity mass measurements; (3) the outer planets are ideal for atmospheric characterization via transmission spectroscopy; and (4) the quietness of the star enables future searches for habitable zone planets. Altogether, very few systems with small, temperate exoplanets are as suitable for such complementary and detailed characterization as TOI-270. [less ▲]Detailed reference viewed: 47 (7 ULiège) NGTS-4b: A sub-Neptune Transiting in the DesertWest, Richard G.; Gillen, Edward; Bayliss, Daniel et alin Monthly Notices of the Royal Astronomical Society (2019), 486We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it ... [more ▼]We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it well within the so-called "Neptunian Desert". The mean density of the planet ($3.45\pm0.95$g/cm^3) is consistent with a composition of 100% H$_2$O or a rocky core with a volatile envelope. NGTS-4b is likely to suffer significant mass loss due to relatively strong EUV/X-ray irradiation. Its survival in the Neptunian desert may be due to an unusually high core mass, or it may have avoided the most intense X-ray irradiation by migrating after the initial activity of its host star had subsided. With a transit depth of $0.13\pm0.02$%, NGTS-4b represents the shallowest transiting system ever discovered from the ground, and is the smallest planet discovered in a wide-field ground-based photometric survey. [less ▲]Detailed reference viewed: 43 (7 ULiège) The L 98-59 System: Three Transiting, Terrestrial-size Planets Orbiting a Nearby M DwarfKostov, Veselin B.; Schlieder, Joshua E.; Barclay, Thomas et alin Astronomical Journal (2019), 158We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia ... [more ▼]We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia- measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the corresponding stellar parameters yield planet radii ranging from 0.8 R [SUB]⊕[/SUB] to 1.6 R [SUB]⊕[/SUB]. All three planets have short orbital periods, ranging from 2.25 to 7.45 days with the outer pair just wide of a 2:1 period resonance. Diagnostic tests produced by the TESS Data Validation Report and the vetting package DAVE rule out common false- positive sources. These analyses, along with dedicated follow-up and the multiplicity of the system, lend confidence that the observed signals are caused by planets transiting L 98-59 and are not associated with other sources in the field. The L 98-59 system is interesting for a number of reasons: the host star is bright (V = 11.7 mag, K = 7.1 mag) and the planets are prime targets for further follow-up observations including precision radial-velocity mass measurements and future transit spectroscopy with the James Webb Space Telescope; the near-resonant configuration makes the system a laboratory to study planetary system dynamical evolution; and three planets of relatively similar size in the same system present an opportunity to study terrestrial planets where other variables (age, metallicity, etc.) can be held constant. L 98-59 will be observed in four more TESS sectors, which will provide a wealth of information on the three currently known planets and have the potential to reveal additional planets in the system. [less ▲]Detailed reference viewed: 50 (4 ULiège) The Ultracool SpeXtroscopic Survey. I. Volume-Limited Spectroscopic Sample and Luminosity Function of M7$-$L5 Ultracool DwarfsBardalez Gagliuffi, Daniella C.; Burgasser, Adam J.; Schmidt, Sarah J. et alE-print/Working paper (2019)We present a volume-limited, spectroscopically-verified sample of M7$-$L5 ultracool dwarfs within 25\,pc. The sample contains 410 sources, of which $93\%$ have trigonometric distance measurements ($80 ... [more ▼]We present a volume-limited, spectroscopically-verified sample of M7$-$L5 ultracool dwarfs within 25\,pc. The sample contains 410 sources, of which$93\%$have trigonometric distance measurements ($80\%$from \textit{Gaia} DR2), and$81\%$have low-resolution ($R\sim120$), near- infrared (NIR) spectroscopy. We also present an additional list of 60 sources which may be M7$-$L5 dwarfs within 25\,pc when distance or spectral type uncertainties are taken into account. The spectra provide NIR spectral and gravity classifications, and we use these to identify young sources, red and blue$J-K_S$color outliers, and spectral binaries. We measure very low gravity and intermediate gravity fractions of$2.1^{+0.9}_{-0.8}\%$and$7.8^{+1.7}_{-1.5}\%$, respectively; fractions of red and blue color outliers of$1.4^{+0.6}_{-0.5}$\% and$3.6^{+1.0}_{-0.9}$\%, respectively; and a spectral binary fraction of$1.6^{+0.5}_{-0.5}\%$. We present an updated luminosity function for M7$-$L5 dwarfs continuous across the hydrogen burning limit that agrees with previous studies. We estimate our completeness to range between$69-80\%$when compared to an isotropic model. However, we find that the literature late-M sample is severely incomplete compared to L dwarfs, with completeness of$62^{+8}_{-7}\%$and$83^{+10}_{-9}\%\$, respectively. This incompleteness can be addressed with astrometric- based searches of ultracool dwarfs with \textit{Gaia} to identify objects previously missed by color- and magnitude-limited surveys. [less ▲]Detailed reference viewed: 30 (3 ULiège) 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: 41 (5 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: 56 (8 ULiège) The EBLM Project. V. Physical properties of ten fully convective, very-low-mass starsvon Boetticher, Alexander; Triaud, Amaury H. M. J.; Queloz, Didier et alin Astronomy and Astrophysics (2019), 625Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing ... [more ▼]Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime, M[SUB]⋆[/SUB] ≲ 0.35 M[SUB]☉[/SUB], down to the hydrogen burning mass- limit, M[SUB]HB[/SUB] ̃ 0.07 M[SUB]☉[/SUB]. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars, performed with the TRAPPIST, Leonhard Euler and SPECULOOS telescopes, and radial velocities of the host stars obtained with the CORALIE spectrograph, to determine the physical properties of the low-mass companions. Surface gravities of the low-mass companions are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models for solar-type stars. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of the binary systems. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are found to be in good agreement with stellar evolution models; a systematic inflation of the radius of low-mass stars with respect to model predictions is limited to 1.6 ± 1.2%, in the fully convective low-mass regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and the orbital periods of the binary systems is determined. A combined analysis with thirteen comparable objects from the literature is consistent with this result. The eclipse and radial velocity data are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/qcat?J/A+A/625/A150 [less ▲]Detailed reference viewed: 178 (3 ULiège)