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We report the discovery of the transiting exoplanets WASP-95b, WASP-96b, WASP-97b, WASP-98b, WASP-99b, WASP-100b andWASP-101b. All are hot Jupiters with orbital periods in the range 2.1-5.7 d, masses of 0.5-2.8 MJup and radii of 1.1-1.4 RJup. The orbits of all the planets are compatible with zero eccentricity. WASP-99b produces the shallowest transit yet found by WASP-South, at 0.4 per cent. The host stars are of spectral type F2-G8. Five have metallicities of [Fe/H] from -0.03 to +0.23, while WASP-98 has a metallicity of -0.60, exceptionally low for a star with a transiting exoplanet. Five of the host stars are brighter than V = 10.8, which significantly extends the number of bright transiting systems available for follow-up studies. WASP-95 shows a possible rotational modulation at a period of 20.7 d. We discuss the completeness of WASP survey techniques by comparing to the HATnet project. Publisher PDF

Since the discovery of the transiting super-Earth CoRoT-7b, several investigations have yielded different results for the number and masses of planets present in the system, mainly owing to the star's high level of activity. We re-observed CoRoT-7 in January 2012 with both HARPS and CoRoT, so that we now have the benefit of simultaneous radial-velocity and photometric data. This allows us to use the off-transit variations in the star's light curve to estimate the radial-velocity variations induced by the suppression of convective blueshift and the flux blocked by starspots. To account for activity-related effects in the radial-velocities which do not have a photometric signature, we also include an additional activity term in the radial-velocity model, which we treat as a Gaussian process with the same covariance properties (and hence the same frequency structure) as the light curve. Our model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b and CoRoT-7c. We measure the masses of planets b and c to be 4.73 +/- 0.95 Mearth and 13.56 +/- 1.08 Mearth, respectively. The density of CoRoT-7b is (6.61 +/- 1.72)(Rp/1.58 Rearth)^(-3) g.cm^(-3), which is compatible with a rocky composition. We search for evidence of an additional planet d, identified by previous authors with a period close to 9 days. We are not able to confirm the existence of a planet with this orbital period, which is close to the second harmonic of the stellar rotation at around 7.9 days. Using Bayesian model selection we find that a model with two planets plus activity-induced variations is most favoured., Accepted 2014 July 2. Received 2014 June 30; in original form 2013 May 30 (17 pages, 9 figures)

We report the discovery of a transiting planet with an orbital period of 1.36d orbiting the brighter component of the visual binary star BD -07 436. The host star, WASP-77A, is a moderately bright G8V star (V=10.3) with a metallicity close to solar ([Fe/H]= 0.0 +- 0.1). The companion star, WASP-77B, is a K-dwarf approximately 2 magnitudes fainter at a separation of approximately 3arcsec. The spectrum of WASP-77A shows emission in the cores of the Ca II H and K lines indicative of moderate chromospheric activity. The WASP lightcurves show photometric variability with a period of 15.3 days and an amplitude of about 0.3% that is probably due to the magnetic activity of the host star. We use an analysis of the combined photometric and spectroscopic data to derive the mass and radius of the planet (1.76+-0.06MJup, 1.21+-0.02RJup). The age of WASP-77A estimated from its rotation rate (~1 Gyr) agrees with the age estimated in a similar way for WASP-77B (~0.6 Gyr) but is in poor agreement with the age inferred by comparing its effective temperature and density to stellar models (~8 Gyr). Follow-up observations of WASP-77 Ab will make a useful contribution to our understanding of the influence of binarity and host star activity on the properties of hot Jupiters.

One focus of modern astronomy is to detect temperate terrestrial exoplanets well-suited for atmospheric characterisation. A milestone was recently achieved with the detection of three Earth-sized planets transiting (i.e. passing in front of) a star just 8% the mass of the Sun 12 parsecs away. Indeed, the transiting configuration of these planets with the Jupiter-like size of their host star - named TRAPPIST-1 - makes possible in-depth studies of their atmospheric properties with current and future astronomical facilities. Here we report the results of an intensive photometric monitoring campaign of that star from the ground and with the Spitzer Space Telescope. Our observations reveal that at least seven planets with sizes and masses similar to the Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.21, 12.35 days) are near ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inward. The seven planets have equilibrium temperatures low enough to make possible liquid water on their surfaces., Comment: 27 pages

The first generation of E-ELT instruments will include an optical-infrared High Resolution Spectrograph, conventionally indicated as EELT-HIRES, which will be capable of providing unique breakthroughs in the fields of exoplanets, star and planet formation, physics and evolution of stars and galaxies, cosmology and fundamental physics. A 2-year long phase A study for EELT-HIRES has just started and will be performed by a consortium composed of institutes and organisations from Brazil, Chile, Denmark, France, Germany, Italy, Poland, Portugal, Spain, Sweden, Switzerland and United Kingdom. In this paper we describe the science goals and the preliminary technical concept for EELT-HIRES which will be developed during the phase A, as well as its planned development and consortium organisation during the study., 12 pages, in Ground-based and Airborne Instrumentation for Astronomy VI, 2016, Proc. SPIE 9908, 23

We present a description of a new instrument development, HARPS3, planned to be installed on an upgraded and roboticized Isaac Newton Telescope by end-2018. HARPS3 will be a high resolution (R = 115,000) echelle spectrograph with a wavelength range from 380-690 nm. It is being built as part of the Terra Hunting Experiment - a future 10 year radial velocity measurement programme to discover Earth-like exoplanets. The instrument design is based on the successful HARPS spectrograph on the 3.6m ESO telescope and HARPS-N on the TNG telescope. The main changes to the design in HARPS3 will be: a customised fibre adapter at the Cassegrain focus providing a stabilised beam feed and on-sky fibre diameter ~ 1.4 arcsec, the implementation of a new continuous flow cryostat to keep the CCD temperature very stable, detailed characterisation of the HARPS3 CCD to map the effective pixel positions and thus provide an improved accuracy wavelength solution, an optimised integrated polarimeter and the instrument integrated into a robotic operation. The robotic operation will optimise our programme which requires our target stars to be measured on a nightly basis. We present an overview of the entire project, including a description of our anticipated robotic operation., Comment: 13 pages, 8 figures, SPIE conference proceedings

We present preliminary results from an experiment designed to measure the effective pixel positions of a CCD to sub-pixel precision. This technique will be used to characterise the 4k x 4k CCD destined for the HARPS-3 spectrograph. The principle of coherent beam interference is used to create intensity fringes along one axis of the CCD. By sweeping the physical parameters of the experiment, the geometry of the fringes can be altered which is used to probe the pixel structure. We also present the limitations of the current experimental set-up and suggest what will be implemented in the future to vastly improve the precision of the measurements.

Context. The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations of ~12000 stars in the galactic plane. An analysis of the raw data identifies the most promising candidates and triggers the ground-based follow-up. Aims. We report on the discovery of the transiting planet CoRoT-Exo-2b, with a period of 1.743 days, and characterize its main parameters. Methods. We filter the CoRoT raw light curve of cosmic impacts, orbital residuals, and low frequency signals from the star. The folded light curve of 78 transits is fitted to a model to obtain the main parameters. Radial velocity data obtained with the SOPHIE, CORALIE and HARPS spectro-graphs are combined to characterize the system. The 2.5 min binned phase-folded light curve is affected by the effect of sucessive occultations of stellar active regions by the planet, and the dispersion in the out of transit part reaches a level of 1.09x10-4 in flux units. Results. We derive a radius for the planet of 1.465+-0.029 R_Jup and a mass of 3.31+-0.16 M_Jup, corresponding to a density of 1.31+-0.04 g/cm^3. The large radius of CoRoT-Exo-2b cannot be explained by current models of evolution of irradiated planets., A&A Letters (in press), 7 pages, 3 figures

The transiting planet CoRoT-1b is thought to belong to the pM-class of planets, in which the thermal emission dominates in the optical wavelengths. We present a detection of its secondary eclipse in the CoRoT white channel data, whose response function goes from ~400 to ~1000 nm. We used two different filtering approaches, and several methods to evaluate the significance of a detection of the secondary eclipse. We detect a secondary eclipse centered within 20 min at the expected times for a circular orbit, with a depth of 0.016+/-0.006%. The center of the eclipse is translated in a 1-sigma upper limit to the planet's eccentricity of ecosomega, 6 pages, to appear in A&A, submitted 18 march 2009, accepted 7 July 2009

With the release of CoRoT lightcurves of the Initial Run IRa01, 50 transiting planetary candidates have been published in a companion paper. About twenty of them were identified as binary stars from the CoRoT lightcurve itself. Complementary observations were conducted for 29 candidates, including ground-based photometry and radial-velocity measurements. Two giant planets were identified and fully characterized. Nineteen binaries are recognized, from which 10 are background eclipsing binaries in the CoRoT mask or triple systems, diluted by the main CoRoT target. Eight cases remain of unclear origin, one of them still being a planetary candidate. Comparison with simulations shows that the actual threshold of confirmed planet detection in this field does not yet fulfill the expectations, and a number of reasons are invoked, like the ranking process based on lightcurve analyses, and the strategy and limits of follow-up observations for targets fainter than magnitude 15.

We report the discovery of three new substellar companions to solar-type stars, HD191806, HD214823, and HD221585, based on radial velocity measurements obtained at the Haute-Provence Observatory. Data from the SOPHIE spectrograph are combined with observations acquired with its predecessor, ELODIE, to detect and characterise the orbital parameters of three new gaseous giant and brown dwarf candidates. Additionally, we combine SOPHIE data with velocities obtained at the Lick Observatory to improve the parameters of an already known giant planet companion, HD16175 b. Thanks to the use of different instruments, the data sets of all four targets span more than ten years. Zero-point offsets between instruments are dealt with using Bayesian priors to incorporate the information we possess on the SOPHIE/ELODIE offset based on previous studies. The reported companions have orbital periods between three and five years and minimum masses between 1.6 Mjup and 19 Mjup. Additionally, we find that the star HD191806 is experiencing a secular acceleration of over 11 \ms\ per year, potentially due to an additional stellar or substellar companion. A search for the astrometric signature of these companions was carried out using Hipparcos data. No orbit was detected, but a significant upper limit to the companion mass can be set for HD221585, whose companion must be substellar. With the exception of HD191806 b, the companions are located within the habitable zone of their host star. Therefore, satellites orbiting these objects could be a propitious place for life to develop., Comment: 12 pages + tables, 7 figures. Accepted for publication in Astronomy & Astrophysics

The search for small planets orbiting late M dwarfs holds the promise of detecting Earth-size planets for which their atmospheres could be characterised within the next decade. The recent discovery of TRAPPIST-1 entertains hope that these systems are common around hosts located at the bottom of the main sequence. In this Letter, we investigate the ability of the repurposed Kepler mission (K2) to probe planetary systems similar to TRAPPIST-1. We perform a consistent data analysis of 189 spectroscopically confirmed M5.5 to M9 late M dwarfs from campaigns 1-6 to search for planet candidates and inject transit signals with properties matching TRAPPIST-1b and c. We find no transiting planet candidates across our K2 sample. Our injection tests show that K2 is able to recover both TRAPPIST-1 planets for 10% of the sample only, mainly because of the inefficient throughput at red wavelengths resulting in Poisson-limited performance for these targets. Increasing injected planetary radii to match GJ1214b's size yields a recovery rate of 70%. The strength of K2 is its ability to probe a large number of cool hosts across the different campaigns, out of which the recovery rate of 10% may turn into bona-fide detections of TRAPPIST-1 like systems within the next two years., 6 pages, 5 figures. Accepted to ApJ Letters on 15 June 2016

We have used photometry from the WASP-South instrument to identify 5 stars showing planet-like transits in their light curves. The planetary nature of the companions to these stars has been confirmed using photometry from the EulerCam instrument on the Swiss Euler 1.2-m telescope and the TRAPPIST telescope, and spectroscopy obtained with the CORALIE spectrograph. The planets discovered are hot Jupiter systems with orbital periods in the range 2.17 to 5.75 days, masses from 0.3M$_{\rm Jup}$ to 1.2M$_{\rm Jup}$ and with radii from 1R$_{\rm Jup}$ to 1.5R$_{\rm Jup}$. These planets orbit bright stars (V = 11-13) with spectral types in the range F9 to G4. WASP-126 is the brightest planetary system in this sample and hosts a low-mass planet with a large radius (0.3 M$_{\rm Jup}$ , 0.95R$_{\rm Jup}$), making it a good target for transmission spectroscopy. The high density of WASP-129 A suggests that it is a helium-rich star similar to HAT-P-11 A. WASP-133 has an enhanced surface lithium abundance compared to other old G-type stars, particularly other planet host stars. These planetary systems are good targets for follow-up observations with ground-based and space-based facilities to study their atmospheric and dynamical properties., Comment: 8 pages, 6 figures. Accepted for publication in A&A

Funding for WASP comes from consortium universities and from UK’s Science and Technology Facilities Council. TRAPPIST is a project funded by the Belgian Fund for Scientific Research (Fonds National de la Recherche Scientifique, F.R.S.-FNRS) under grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Fundation (SNF). The Swiss Euler Telescope is operated by the University of Geneva, and is funded by the Swiss National Science Foundation. LD acknowledges support of the F.R.I.A. fund of the FNRS. MG, EJ and VVG are FNRS Research Associates. ML acknowledges support of the European Research Council through the European Union‘s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement number 336480. AHMJT received funding from a fellowship provided by the Swiss National Science Foundation under grant number P300P2-147773.ASis supported by the European Union under a Marie Curie Intra-European Fellowship for Career Development with reference FP7-PEOPLE- 2013-IEF, number 627202. We present the discovery by the WASP-South survey of WASP-121 b, a new remarkable short-period transiting hot Jupiter. The planet has a mass of 1.183+0.064−0.062 MJup, a radius of 1.865 ± 0.044 RJup, and transits every 1.2749255+0.0000020−0.0000025 days an active F6-type main-sequence star (V = 10.4, 1.353+0.080−0.079 M⊙, 1.458 ± 0.030 R⊙, Teff = 6460 ± 140 K). A notable property of WASP-121 b is that its orbital semimajor axis is only ∼1.15 times larger than its Roche limit, which suggests that the planet is close to tidal disruption. Furthermore, its large size and extreme irradiation (∼7.1 109 erg s−1 cm−2) make it an excellent target for atmospheric studies via secondary eclipse observations. Using the TRAnsiting Planets and PlanetesImals Small Telescope, we indeed detect its emission in the z′-band at better than ∼4σ, the measured occultation depth being 603 ± 130 ppm. Finally, from a measurement of the Rossiter–McLaughlin effect with the CORALIE spectrograph, we infer a sky-projected spin-orbit angle of 257∘.8+5∘.3−5∘.5. This result may suggest a significant misalignment between the spin axis of the host star and the orbital plane of the planet. If confirmed, this high misalignment would favour a migration of the planet involving strong dynamical events with a third body. Publisher PDF

We present the discovery by the WASP-South survey of three planets transiting moderately bright stars (V ~ 11). WASP-120b is a massive (5.0MJup) planet in a 3.6-day orbit that we find likely to be eccentric (e = 0.059+0.025-0.018) around an F5 star. WASP-122b is a hot-Jupiter (1.37MJup, 1.79RJup) in a 1.7-day orbit about a G4 star. Our predicted transit depth variation cause by the atmosphere of WASP-122b suggests it is well suited to characterisation. WASP-123b is a hot-Jupiter (0.92MJup, 1.33RJup) in a 3.0-day orbit around an old (~ 7 Gyr) G5 star., 15 pages, 10 figures, 5 tables

Three Earth-sized exoplanets were recently discovered close to the habitable zone of the nearby ultracool dwarf star TRAPPIST-1. The nature of these planets has yet to be determined, since their masses remain unmeasured and no observational constraint is available for the planetary population surrounding ultracool dwarfs, of which the TRAPPIST-1 planets are the first transiting example. Theoretical predictions span the entire atmospheric range from depleted to extended hydrogen-dominated atmospheres. Here, we report a space-based measurement of the combined transmission spectrum of the two inner planets made possible by a favorable alignment resulting in their simultaneous transits on 04 May 2016. The lack of features in the combined spectrum rules out cloud-free hydrogen-dominated atmospheres for each planet at 10-$\sigma$ levels; TRAPPIST-1 b and c are hence unlikely to harbor an extended gas envelope as they lie in a region of parameter space where high-altitude cloud/haze formation is not expected to be significant for hydrogen-dominated atmospheres. Many denser atmospheres remain consistent with the featureless transmission spectrum---from a cloud-free water vapour atmosphere to a Venus-like atmosphere., Comment: Early release to inform further the upcoming review of HST's Cycle 24 proposals

Three Earth-sized planets—receiving similar irradiation to Venus and Earth, and ideally suited for atmospheric study—have been found transiting a nearby ultracool dwarf star that has a mass of only eight per cent of that of the Sun. Theory predicts that terrestrial or rocky planets are likely to be orbiting the lowest-mass stars. This paper reports the detection of a system of three Earth-sized planets transiting a very nearby (12 parsec) ultracool dwarf star of only 8% of the mass of the Sun. The planets are similar in irradiation to Venus and Earth, and particularly well suited for detailed atmospheric characterization. Star-like objects with effective temperatures of less than 2,700 kelvin are referred to as ‘ultracool dwarfs’1. This heterogeneous group includes stars of extremely low mass as well as brown dwarfs (substellar objects not massive enough to sustain hydrogen fusion), and represents about 15 per cent of the population of astronomical objects near the Sun2. Core-accretion theory predicts that, given the small masses of these ultracool dwarfs, and the small sizes of their protoplanetary disks3,4, there should be a large but hitherto undetected population of terrestrial planets orbiting them5—ranging from metal-rich Mercury-sized planets6 to more hospitable volatile-rich Earth-sized planets7. Here we report observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away. The inner two planets receive four times and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star8. Our data suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth. The infrared brightness of the host star, combined with its Jupiter-like size, offers the possibility of thoroughly characterizing the components of this nearby planetary system.

Stellar metallicity -- as a probe of the metallicity of proto-planetary disks -- is an important ingredient for giant planet formation, likely through its effect on the timescales in which rocky/icy planet cores can form. Giant planets have been found to be more frequent around metal-rich stars, in agreement with predictions based on the core-accretion theory. In the metal-poor regime, however, the frequency of planets, especially low-mass planets, and how it depends on metallicity are still largely unknown. As part of a planet search programme focused on metal-poor stars, we study the targets from this survey that were observed with HARPS on more than 75 nights. The main goals are to assess the presence of low-mass planets and provide a first estimate of the frequency of Neptunes and super-Earths around metal-poor stars. We perform a systematic search for planetary companions, both by analysing the periodograms of the radial-velocities and by comparing, in a statistically-meaningful way, models with an increasing number of Keplerians. A first constraint on the frequency of planets in our metal-poor sample is calculated considering the previous detection (in our sample) of a Neptune-sized planet around HD175607 and one candidate planet (with an orbital period of 68.42d and minimum mass $M_p \sin i = 11.14 \pm 2.47 M_{\oplus}$) for HD87838, announced in the present study. This frequency is determined to be close to 13% and is compared with results for solar-metallicity stars., Comment: 18 pages, 29 figures, 4 tables, accepted for publication in A&A

Over the past decade, observations of giant exoplanets (Jupiter-size) have provided key insights into their atmospheres, but the properties of lower-mass exoplanets (sub-Neptune) remain largely unconstrained because of the challenges of observing small planets. Numerous efforts to observe the spectra of super-Earths (exoplanets with masses of one to ten times that of Earth) have so far revealed only featureless spectra. Here we report a longitudinal thermal brightness map of the nearby transiting super-Earth 55 Cancri e revealing highly asymmetric dayside thermal emission and a strong day-night temperature contrast. Dedicated space-based monitoring of the planet in the infrared revealed a modulation of the thermal flux as 55 Cancri e revolves around its star in a tidally locked configuration. These observations reveal a hot spot that is located 41 +- 12 degrees east of the substellar point (the point at which incident light from the star is perpendicular to the surface of the planet). From the orbital phase curve, we also constrain the nightside brightness temperature of the planet to 1380 +- 400 kelvin and the temperature of the warmest hemisphere (centred on the hot spot) to be about 1300 kelvin hotter (2700 +- 270 kelvin) at a wavelength of 4.5 microns, which indicates inefficient heat redistribution from the dayside to the nightside. Our observations are consistent with either an optically thick atmosphere with heat recirculation confined to the planetary dayside, or a planet devoid of atmosphere with low-viscosity magma flows at the surface., Comment: Published in Nature on 14 April 2016. Preprint version includes 32 pages, 11 figures and 2 tables

The Sun is the only star whose surface can be directly resolved at high resolution, and therefore constitutes an excellent test case to explore the physical origin of stellar radial-velocity (RV) variability. We present HARPS observations of sunlight scattered off the bright asteroid 4/Vesta, from which we deduced the Sun's activity-driven RV variations. In parallel, the HMI instrument onboard the Solar Dynamics Observatory provided us with simultaneous high spatial resolution magnetograms, Dopplergrams, and continuum images of the Sun in the Fe I 6173A line. We determine the RV modulation arising from the suppression of granular blueshift in magnetised regions and the flux imbalance induced by dark spots and bright faculae. The rms velocity amplitudes of these contributions are 2.40 m/s and 0.41 m/s, respectively, which confirms that the inhibition of convection is the dominant source of activity-induced RV variations at play, in accordance with previous studies. We find the Doppler imbalances of spot and plage regions to be only weakly anticorrelated. Lightcurves can thus only give incomplete predictions of convective blueshift suppression. We must instead seek proxies that track the plage coverage on the visible stellar hemisphere directly. The chromospheric flux index R'_HK derived from the HARPS spectra performs poorly in this respect, possibly because of the differences in limb brightening/darkening in the chromosphere and photosphere. We also find that the activity-driven RV variations of the Sun are strongly correlated with its full-disc magnetic flux density, which may become a useful proxy for activity-related RV noise., 14 pages, 11 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society (2016 January 20) Supplementary Files available at: http://dx.doi.org/10.17630/bb43e6a3-72e0-464c-9fdd-fbe5d3e56a09

Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own Solar System. A transition from rocky to gaseous planets with a planetary transition radius of ~1.6 REarth has recently been proposed by several publications in the literature (Rogers 2015;Weiss & Marcy 2014). Kepler-20b (Rp ~ 1.9 REarth) has a size beyond this transition radius, however previous mass measurements were not sufficiently precise to allow definite conclusions to be drawn regarding its composition. We present new mass measurements of three of the planets in the Kepler-20 system facilitated by 104 radial velocity measurements from the HARPS-N spectrograph and 30 archival Keck/HIRES observations, as well as an updated photometric analysis of the Kepler data and an asteroseismic analysis of the host star (MStar = 0.948+-0.051 Msun and Rstar = 0.964+-0.018 Rsun). Kepler-20b is a 1.868+0.066-0.034 REarth planet in a 3.7 day period with a mass of 9.70+1.41-1.44 MEarth resulting in a mean density of 8.2+1.5-1.3 g/cc indicating a rocky composition with an iron to silicate ratio consistent with that of the Earth. This makes Kepler-20b the most massive planet with a rocky composition found to date. Furthermore, we report the discovery of an additional non-transiting planet with a minimum mass of 19.96+3.08-3.61 MEarth and an orbital period of ~34 days in the gap between Kepler-20f (P ~ 11 days) and Kepler-20d (P ~ 78 days)., 33 pages, 8 figures. Accepted for publication in AJ

We present a yield simulator to predict the number and characteristics of planets, false positives and false alarms in transit surveys. The simulator is based on a galactic model and the planet occurrence rates measured by the Kepler mission. It takes into account the observation window function and measured noise levels of the investigated survey. Additionally, it includes vetting criteria to identify false positives. We apply this simulator to the Next Generation Transit Survey (NGTS), a wide-field survey designed to detect transiting Neptune-sized exoplanets. We find that red noise is the main limitation of NGTS up to 14th magnitude, and that its obtained level determines the expected yield. Assuming a red noise level of 1 mmag, the simulation predicts the following for a four-year survey: 4+-3 Super-Earths, 19+-5 Small Neptunes, 16+-4 Large Neptunes, 55+-8 Saturn-sized planets and 150+-10 Jupiter-sized planets, along with 4688+-45 eclipsing binaries and 843+-75 background eclipsing binaries. We characterize the properties of these objects to enhance the early identification of false positives and discuss follow-up strategies for transiting candidates., Comment: Accepted for publication in MNRAS 07 Nov 2016. 12 pages, 10 figures, 3 tables. This is the authors' version of the manuscript

Context. The presence of a small-mass planet (M$_p, Comment: 12 pages, 9 figures, accepted for publication in Astronomy and Astrophysics

We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly averaged velocity measurements for each star. This means that it is sensitive to both long-period and low-mass planets and also to the effects induced by stellar activity cycles. We modelled the data using Keplerian functions that correspond to planetary candidates and included the short- and long-term effects of magnetic activity. A Bayesian approach was taken both for the data modelling, which allowed us to include information from activity proxies such as $\log{(R'_{\rm HK})}$ in the velocity modelling, and for the model selection, which permitted determining the number of significant signals in the system. The Bayesian model comparison overcomes the limitations inherent to the traditional periodogram analysis. We report an additional super-Earth planet in the HD1461 system. Four out of the six planets previously reported for HD40307 are confirmed and characterised. We discuss the remaining two proposed signals. In particular, we show that when the systematic uncertainty associated with the techniques for estimating model probabilities are taken into account, the current data are not conclusive concerning the existence of the habitable-zone candidate HD40307 g. We also fully characterise the Neptune-mass planet that orbits HD204313 in 34.9 days., Comment: 23 pages + online material, 23 figures. Accepted for publication in A&A. Small typos and series numbering corrected

HD 179070, aka Kepler-21, is a V = 8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. (2012) of the first thirteen months (Q0 - Q5) of Kepler light curves revealed transits of a planetary companion, Kepler-21b, with a radius of about 1.60 +/- 0.04 R_earth and an orbital period of about 2.7857 days. However, they could not determine the mass of the planet from the initial radial velocity observations with Keck-HIRES, and were only able to impose a 2-sigma upper limit of 10 M_earth. Here we present results from the analysis of 82 new radial velocity observations of this system obtained with HARPS-N, together with the existing 14 HIRES data points. We detect the Doppler signal of Kepler-21b with a radial velocity semi-amplitude K = 2.00 +/- 0.65 m/s, which corresponds to a planetary mass of 5.1 +/- 1.7 M_earth. We also measure an improved radius for the planet of 1.639 (+0.019, -0.015) R_earth, in agreement with the radius reported by Howell et al. (2012). We conclude that Kepler-21b, with a density of 6.4 +/- 2.1 g/cm^3, belongs to the population of terrestrial planets with iron, magnesium silicate interiors, which have lost the majority of their envelope volatiles via stellar winds or gravitational escape. The radial velocity analysis presented in this paper serves as example of the type of analysis that will be necessary to confirm the masses of TESS small planet candidates.

While the vast majority of multiple-planet systems have their orbital angular momentum axes aligned with the spin axis of their host star, Kepler-56 is an exception: its two transiting planets are coplanar yet misaligned by at least 40 degrees with respect to their host star. Additional follow-up observations of Kepler-56 suggest the presence of a massive, non-transiting companion that may help explain this misalignment. We model the transit data along with Keck/HIRES and HARPS-N radial velocity data to update the masses of the two transiting planets and infer the physical properties of the third, non-transiting planet. We employ a Markov Chain Monte Carlo sampler to calculate the best-fitting orbital parameters and their uncertainties for each planet. We find the outer planet has a period of 1002 $\pm$ 5 days and minimum mass of 5.61 $\pm$ 0.38 Jupiter masses. We also place a 95% upper limit of 0.80 m/s/yr on long-term trends caused by additional, more distant companions., Comment: 7 pages, 1 figure, 2 tables; accepted for publication in AJ. Minor edits made after referee report

Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like starthat hosts a transiting planet candidate in a 10.6 d orbit. From spectroscopy, we estimate the stellar temperature to be 5687 +/- 50 K, its metallicity to be [m/H] = 0.32 +/- 0.08, and the projected rotational velocity to be v sin i 10 years and mass >12.1M_J . The twelve exoplanets with radii, 40 pages, 13 figures, 6 pages; ApJ in press

We present the discovery of three new transiting giant planets, first detected with the WASP telescopes, and establish their planetary nature with follow up spectroscopy and ground-based photometric lightcurves. WASP-92 is an F7 star, with a moderately inflated planet orbiting with a period of 2.17 days, which has $R_p = 1.461 \pm 0.077 R_{\rm J}$ and $M_p = 0.805 \pm 0.068 M_{\rm J}$. WASP-93b orbits its F4 host star every 2.73 days and has $R_p = 1.597 \pm 0.077 R_{\rm J}$ and $M_p = 1.47 \pm 0.029 M_{\rm J}$. WASP-118b also has a hot host star (F6) and is moderately inflated, where $R_p = 1.440 \pm 0.036 R_{\rm J}$ and $M_p = 0.513 \pm 0.041 M_{\rm J}$ and the planet has an orbital period of 4.05 days. They are bright targets (V = 13.18, 10.97 and 11.07 respectively) ideal for further characterisation work, particularly WASP-118b, which is being observed by K2 as part of campaign 8. WASP-93b is expected to be tidally migrating outwards, which is divergent from the tidal behaviour of the majority of hot Jupiters discovered., Comment: 14 pages, 10 figures; submitted to MNRAS

We announce the discovery of the transiting hot Jupiter WASP-157b in a 3.95-d orbit around a V = 12.9 G2 main-sequence star. This moderately inflated planet has a Saturn-like density with a mass of $0.57 \pm 0.10$ M$_{\rm Jup}$ and a radius of $1.06 \pm 0.05$ R$_{\rm Jup}$. We do not detect any rotational or phase-curve modulations, nor the secondary eclipse, with conservative semi-amplitude upper limits of 250 and 20 ppm, respectively., Comment: 6 pages, 5 figures and 4 tables. Accepted for publication in PASP

We have made a detailed spectral analysis of eleven Wide Angle Search for Planets (WASP) planet host stars using high signal-to-noise (S/N) HARPS spectra. Our line list was carefully selected from the spectra of the Sun and Procyon, and we made a critical evaluation of the atomic data. The spectral lines were measured using equivalent widths. The procedures were tested on the Sun and Procyon prior to be being used on the WASP stars. The effective temperature, surface gravity, microturbulent velocity and metallicity were determined for all the stars. We show that abundances derived from high S/N spectra are likely to be higher than those obtained from low S/N spectra, as noise can cause the equivalent width to be underestimated. We also show that there is a limit to the accuracy of stellar parameters that can be achieved, despite using high S/N spectra, and the average uncertainty in effective temperature, surface gravity, microturbulent velocity and metallicity is 83 K, 0.11 dex, 0.11 km/s and 0.10 dex respectively., 9 pages, 5 figures, accepted for publication in MNRAS

Exoplanets down to the size of Earth have been found, but not in the habitable zone—that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water–carbon life as we know it. The detection of a habitable Earth-mass planet orbiting a star similar to our Sun is extremely difficult, because such a signal is overwhelmed by stellar perturbations. Here we report the detection of an Earth-mass planet orbiting our neighbour star α Centauri B, a member of the closest stellar system to the Sun. The planet has an orbital period of 3.236 days and is about 0.04 astronomical units from the star (one astronomical unit is the Earth–Sun distance). The detection of an Earth-mass planet orbiting our neighbour star α Centauri B is reported; the planet has an orbital period of 3.236 days and is about 0.04 astronomical units from the star. An exoplanet with an Earth-like mass has been discovered orbiting the nearby star α Centauri B. The planet is not in the habitable zone — it is much nearer to its star than we are to the Sun, orbiting at only about 0.04 astronomical units from its star (an astronomical unit is the mean distance between Earth and the Sun). Statistical studies suggest that low-mass planets form preferentially in multi-planet systems, so it is possible that other planets are orbiting α Centauri B, perhaps in its habitable zone.

We present new measurements of the Rossiter-McLaughlin (RM) effect for three WASP planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis of their complete sets of photometric and spectroscopic data. We find a low amplitude RM effect for WASP-16 (Teff = 5700 \pm 150K), suggesting that the star is a slow rotator and thus of an advanced age, and obtain a projected alignment angle of lambda = -4.2 degrees +11.0 -13.9. For WASP-25 (Teff = 5750\pm100K) we detect a projected spin-orbit angle of lambda = 14.6 degrees \pm6.7. WASP-31 (Teff = 6300\pm100K) is found to be well-aligned, with a projected spin-orbit angle of lambda = 2.8degrees \pm3.1. A circular orbit is consistent with the data for all three systems, in agreement with their respective discovery papers. We consider the results for these systems in the context of the ensemble of RM measurements made to date. We find that whilst WASP-16 fits the hypothesis of Winn et al. (2010) that 'cool' stars (Teff < 6250K) are preferentially aligned, WASP-31 has little impact on the proposed trend. We bring the total distribution of the true spin-orbit alignment angle, psi, up to date, noting that recent results have improved the agreement with the theory of Fabrycky & Tremaine (2007) at mid-range angles. We also suggest a new test for judging misalignment using the Bayesian Information Criterion, according to which WASP-25 b's orbit should be considered to be aligned.

We report the discovery of three extrasolar planets that transit their moderately bright (Vmag = 12-13) host stars. WASP-44b is a 0.89-MJup planet in a 2.42-day orbit around a G8V star. WASP-45b is a 1.03-MJup planet which passes in front of the limb of its K2V host star every 3.13 days. Weak Ca II H+K emission seen in the spectra of WASP-45 suggests the star is chromospherically active. WASP-46b is a 2.10-MJup planet in a 1.43-day orbit around a G6V star. Rotational modulation of the light curves of WASP-46 and weak Ca II H+K emission in its spectra show the star to be photospherically and chromospherically active. We imposed circular orbits in our analyses as the radial velocity data are consistent with (near-)circular orbits, as could be expected from both empirical and tidal-theory perspectives for such short-period, Jupiter-mass planets. We discuss the impact of fitting for eccentric orbits for such planets when not supported by the data. The derived planetary and stellar radii depend on the fitted eccentricity and these parameters inform intense theoretical efforts concerning tidal circularisation and heating, bulk planetary composition and the observed systematic errors in planetary and stellar radii. As such, we recommend exercising caution in fitting the orbits of short period, Jupiter-mass planets with an eccentric model when there is no evidence of non-circularity.

We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b, in addition to eight new measurements of the radial velocity of the star. Thanks to this extensive data set, we improve significantly the parameters of the system. Notably, the largely improved precision on the stellar density (2.41+-0.08 rho_sun) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper. The resulting stellar mass and size are 0.717+-0.025 M_sun and 0.667+-0.011 R_sun. Our deduced physical parameters for the planet are 2.034+-0.052 M_jup and 1.036+-0.019 R_jup. Taking into account its level of irradiation, the high density of the planet favors an old age and a massive core. Our deduced orbital eccentricity, 0.0035(-0.0025,+0.0060), is consistent with a fully circularized orbit. We detect the emission of the planet at 2.09 microns at better than 11-sigma, the deduced occultation depth being 1560+-140 ppm. Our detection of the occultation at 1.19 microns is marginal (790+-320 ppm) and more observations are needed to confirm it. We place a 3-sigma upper limit of 850 ppm on the depth of the occultation at ~0.9 microns. Together, these results strongly favor a poor redistribution of the heat to the night-side of the planet, and marginally favor a model with no day-side temperature inversion., Comment: 14 pages, 6 tables, 11 figures. Accepted for publication in A&A

Context: Transmission spectroscopy has proven to be a useful tool for the study of exoplanet atmospheres, and has lead to the detection of a small number of elements and molecules (Na, K, H$_2$O), but also revealed that many planets show flat transmission spectra consistent with the presence of opaque high-altitude hazes or clouds. Aims: We apply this technique to the $M_P=0.38 M_{jup}$, $R_p=1.12 R_{jup}$, $P=2.78d$ planet WASP-49b, aiming to characterize its transmission spectrum between 0.73 and 1 $\mathrm{\mu}$m and search for the features of K and H$_2$O. Methods: Three transits of WASP-49b have been observed with the FORS2 instrument installed at the VLT/UT1 telescope at the ESO Paranal site. We used FORS2 in MXU mode with grism GRIS_600z, producing simultaneous multiwavelength transit lightcurves throughout the i' and z' bands. We combined these data with independent broadband photometry from the Euler and TRAPPIST telescopes to obtain a good measurement of the transit shape. Strong correlated noise structures are present in the FORS2 lightcurves, which are due to rotating flat-field structures that are introduced by inhomogeneities of the linear atmospheric dispersion corrector's transparency. We accounted for these structures by constructing common noise models from the residuals of lightcurves bearing the same noise structures, and used them together with simple parametric models to infer the transmission spectrum. Results: We present three independent transmission spectra of WASP-49b between 0.73 and 1.02 $\mu m$, as well as a transmission spectrum between 0.65 and 1.02 $\mu m$ from the combined analysis of FORS2 and broadband data. The results obtained from the three individual epochs agree well. The transmission spectrum of WASP-49b is best fit by atmospheric models containing a cloud deck at pressure levels of 1 mbar or lower., Comment: accepted for publication in A&A

We present observations of the Rossiter-McLaughlin effect for the transiting exoplanet systems WASP-1, WASP-24, WASP-38 and HAT-P-8, and deduce the orientations of the planetary orbits with respect to the host stars' rotation axes. The planets WASP-24b, WASP-38b and HAT-P-8b appear to move in prograde orbits and be well aligned, having sky-projected spin orbit angles consistent with zero: {\lambda} = -4.7 \pm 4.0{\deg}, {\lambda} = 15 + 33{\deg}/-43{\deg} and {\lambda} = -9.7 +9.0{\deg}/-7.7{\deg}, respectively. The host stars have Teff < 6250 K and conform with the trend of cooler stars having low obliquities. WASP-38b is a massive planet on a moderately long period, eccentric orbit so may be expected to have a misaligned orbit given the high obliquities measured in similar systems. However, we find no evidence for a large spin-orbit angle. By contrast, WASP-1b joins the growing number of misaligned systems and has an almost polar orbit, {\lambda} = -79 +4.5{\deg}/-4.3{\deg}. It is neither very massive, eccentric nor orbiting a hot host star, and therefore does not share the properties of many other misaligned systems.

We report the discovery of a transiting planet with an orbital period of 3.05d orbiting the star TYC 7247-587-1. The star, WASP-41, is a moderately bright G8V star (V=11.6) with a metallicity close to solar ([Fe/H]=-0.08+-0.09). The star shows evidence of moderate chromospheric activity, both from emission in the cores of the CaII H and K lines and photometric variability with a period of 18.4d and an amplitude of about 1%. We use a new method to show quantitatively that this periodic signal has a low false alarm probability. The rotation period of the star implies a gyrochronological age for WASP-41 of 1.8Gyr with an error of about 15%. We have used a combined analysis of the available photometric and spectroscopic data to derive the mass and radius of the planet (0.92+-0.06M_Jup, 1.20+-0.06R_Jup). Further observations of WASP-41 can be used to explore the connections between the properties of hot Jupiter planets and thelevel of chromospheric activity in their host stars., Revised version accepted for publication in PASP

We report the detection of four new extrasolar planets in orbit around the moderately active stars HD 63765, HD 104067, HIP 70849, and HD 125595 with the HARPS Echelle spectrograph mounted on the ESO 3.6-m telescope at La Silla. The first planet, HD 63765 b, has a minimum mass of 0.64MJup, a period of 358 days, and an eccentricity of 0.24. It orbits a G9 dwarf at 0.94 AU. The second planet, HD 104067 b, is a 3.6 Neptune-mass-planet with a 55.8-day-period. It orbits its parent K2 dwarf, in a circular orbit with a semi-major axis of a=0.26 AU. Radial velocity measurements present a \approx 500-day-oscillation that reveals significant magnetic cycles. The third planet is a 0.77 Neptune-mass-planet in circular orbit around the K4 dwarf, HD 12595, with a 9.67-day-period. Finally, HIP 7849 b is a long-period (5< P, Accepted for publication in A\&A, 8 pages, 8 figures, 3 tables

We report the discovery of a transiting planet orbiting the star TYC 6446-326-1. The star, WASP-22, is a moderately bright (V=12.0) solar-type star (Teff = 6000 +/- 100 K, [Fe/H] = -0.05 +/- 0.08). The lightcurve of the star obtained with the WASP-South instrument shows periodic transit-like features with a depth of about 1 and a duration of 0.14 days. The presence of a transit-like feature in the lightcurve is confirmed using z-band photometry obtained with Faulkes Telescope South. High resolution spectroscopy obtained with the CORALIE and HARPS spectrographs confirm the presence of a planetary mass companion with an orbital period of 3.533 days in a near-circular orbit. From a combined analysis of the spectroscopic and photometric data assuming that the star is a typical main-sequence star we estimate that the planet has a mass M_p = 0.56 +/- 0.02 M_Jup and a radius R_p = 1.12 +/- 0.04 R_Jup. In addition, there is a linear trend of 40 m/s/yr in the radial velocities measured over 16 months, from which we infer the presence of a third body with a long period orbit in this system. The companion may be a low mass M-dwarf, a white dwarf or a second planet., Accepted for publication in AJ. Replaced submitted version with accepted version

In order to understand general planet characteristics and constrain formation models it is necessary to scan over the widest possible parameter range of discovered systems. Due to detection biases, the domain of very-low mass planets had remained poorly explored. Only with improving measurement precision it has been possible to enter in the sub-Neptune mass range. The HARPS planet search program has been particularly efficient in detecting such ice giants and super earths. The present talk will summarize the obtained results and the characteristics of the low-mass population of exoplanets.

We will present our campaign to estimate the projected spin-orbit angle for transiting hot Jupiters, obtained via observations of the Rossiter-McLaughlin effect. Combining our results to those of other teams we show what the current distribution in projected spin-orbit angle is, quickly reminding what interpretation we make of it. Finally we will show early results from a campaign that we initiated, surveying the Rossiter-McLaughlin effect on transiting SB1 intended to provide a comparison sample to the transiting planet's results.

We report the discovery of four super-Earth planets around HD 215152, with orbital periods of 5.76, 7.28, 10.86, and 25.2 d, and minimum masses of 1.8, 1.7, 2.8, and 2.9 M_Earth respectively. This discovery is based on 373 high-quality radial velocity measurements taken by HARPS over 13 years. Given the low masses of the planets, the signal-to-noise ratio is not sufficient to constrain the planet eccentricities. However, a preliminary dynamical analysis suggests that eccentricities should be typically lower than about 0.03 for the system to remain stable. With two pairs of planets with a period ratio lower than 1.5, with short orbital periods, low masses, and low eccentricities, HD 215152 is similar to the very compact multi-planet systems found by Kepler, which is very rare in radial-velocity surveys. This discovery proves that these systems can be reached with the radial-velocity technique, but characterizing them requires a huge amount of observations., Accepted for publication in A&A

Surveys for exoplanetary transits are usually limited not by photon noise but rather by the amount of red noise in their data. In particular, although the CoRoT spacebased survey data are being carefully scrutinized, significant new sources of systematic noises are still being discovered. Recently, a magnitude-dependant systematic effect was discovered in the CoRoT data by Mazeh & Guterman et al. and a phenomenological correction was proposed. Here we tie the observed effect a particular type of effect, and in the process generalize the popular Sysrem algorithm to include external parameters in a simultaneous solution with the unknown effects. We show that a post-processing scheme based on this algorithm performs well and indeed allows for the detection of new transit-like signals that were not previously detected., MNRAS accepted. 5 pages, 3 figures

TRAPPIST-1 is an ultracool dwarf star transited by seven Earth-sized planets, for which thorough characterization of atmospheric properties, surface conditions encompassing habitability and internal compositions is possible with current and next generation telescopes. Accurate modeling of the star is essential to achieve this goal. We aim to obtain updated stellar parameters for TRAPPIST- 1 based on new measurements and evolutionary models, compared to those used in discovery studies. We present a new measurement for the parallax of TRAPPIST-1, 82.4 $\pm$ 0.8 mas, based on 188 epochs of observations with the TRAPPIST and Liverpool Telescopes from 2013 to 2016. This revised parallax yields an updated luminosity of $L_*=(5.22\pm0.19)\times 10^{-4} L_{\odot}$, very close to the previous estimate but almost twice more precise. We next present an updated estimate for TRAPPIST-1 stellar mass, based on two approaches: mass from stellar evolution modeling, and empirical mass derived from dynamical masses of equivalently classified ultracool dwarfs in astrometric binaries. We combine them through a Monte-Carlo approach to derive a semi-empirical estimate for the mass of TRAPPIST-1. We also derive estimate for the radius by combining this mass with stellar density inferred from transits, as well as estimate for the effective temperature from our revised luminosity and radius. Our final results are $M_*=0.089 \pm 0.006 M_{\odot}$, $R_* = 0.121 \pm 0.003 R_{\odot}$, and $T_{\rm eff} =$ 2516 $\pm$ 41 K. Considering the degree to which TRAPPIST-1 system will be scrutinized in coming years, these revised and more precise stellar parameters should be considered when assessing the properties of TRAPPIST-1 planets., Accepted for publication in Astrophysical Journal

We report the discovery of a Saturn-sized planet transiting a V = 11.3, K4 dwarf star every 3.9 d. WASP-29b has a mass of 0.24+/-0.02 M_Jup and a radius of 0.79+/-0.05 R_Jup, making it the smallest planet so far discovered by the WASP survey, and the exoplanet most similar in mass and radius to Saturn. The host star WASP-29 has an above-Solar metallicity and fits a possible correlation for Saturn-mass planets such that planets with higher-metallicity host stars have higher core masses and thus smaller radii., 6 pages, submitted to ApJL

A decade ago, the detection of the first1, 2 transiting extrasolar planet provided a direct constraint on its composition and opened the door to spectroscopic investigations of extrasolar planetary atmospheres3. Because such characterization studies are feasible only for transiting systems that are both nearby and for which the planet-to-star radius ratio is relatively large, nearby small stars have been surveyed intensively. Doppler studies4, 5, 6 and microlensing7 have uncovered a population of planets with minimum masses of 1.9–10 times the Earth’s mass (Mcircle plus), called super-Earths. The first constraint on the bulk composition of this novel class of planets was afforded by CoRoT-7b (refs 8, 9), but the distance and size of its star preclude atmospheric studies in the foreseeable future. Here we report observations of the transiting planet GJ 1214b, which has a mass of 6.55Mcircle plus and a radius 2.68 times Earth’s radius (Rcircle plus), indicating that it is intermediate in stature between Earth and the ice giants of the Solar System. We find that the planetary mass and radius are consistent with a composition of primarily water enshrouded by a hydrogen–helium envelope that is only 0.05% of the mass of the planet. The atmosphere is probably escaping hydrodynamically, indicating that it has undergone significant evolution during its history. The star is small and only 13 parsecs away, so the planetary atmosphere is amenable to study with current observatories., National Science Foundation (U.S.) (grant number AST-0807690), United States. National Aeronautics and Space Administration (NASA Kepler mission under cooperative agreement NCC2-1390), United States. National Aeronautics and Space Administration (NASA Origins Grant NNX09AB33G), David & Lucile Packard Foundation

We present Spitzer Space Telescope time series photometry of the exoplanet system HD 189733 spanning two times of secondary eclipse, when the planet passes out of view behind the parent star. We estimate the relative eclipse depth in 5 distinct bands and find the planet-to-star flux ratio to be 0.256 +/- 0.014% (3.6 microns), 0.214 +/- 0.020% (4.5 microns), 0.310 +/- 0.034% (5.8 microns), 0.391 +/- 0.022% (8.0 microns), and 0.598 +/- 0.038% (24 microns). For consistency, we re-analyze a previously published time series to deduce a contrast ratio in an additional band, 0.519 +/- 0.020% (16 microns). Our data are strongly inconsistent with a Planck spectrum, and we clearly detect emission near 4 microns as predicted by published theoretical models in which this feature arises from a corresponding opacity window. Unlike recent results for the exoplanet HD 209458b, we find that the emergent spectrum from HD 189733b is best matched by models that do not include an atmospheric temperature inversion. Taken together, these two studies provide initial observational support for the idea that hot Jupiter atmospheres diverge into two classes, in which a thermal inversion layer is present for the more strongly irradiated objects., 20 pages, 3 figures, accepted to the Astrophysical Journal, minor revisions

A 10.24 days Neptune-mass planet was recently announced to orbit the nearby M2 dwarf Gl 176, based on 28 radial velocities measured with the HRS spectrograph on the Hobby-Heberly Telescope (HET). We obtained 57 radial velocities of Gl 176 with the ESO 3.6m telescope and the HARPS spectrograph, which is known for its sub-m/s stability. The median photon-noise standard error of our measurements is 1.1 m/s, significantly lower than the 4.7 m/s of the HET velocities, and the 4 years period over which they were obtained has much overlap with the epochs of the HET measurements. The HARPS measurements show no evidence for a signal at the period of the putative HET planet, suggesting that its detection was spurious. We do find, on the other hand, strong evidence for a lower mass 8.4 Mearth planet, in a quasi-circular orbit and at the different period of 8.78 days. The host star has moderate magnetic activity and rotates on a 39-days period, which we confirm through modulation of both contemporaneous photometry and chromospheric indices. We detect that period as well in the radial velocities, but it is well removed from the orbital period and no cause for confusion. This new detection of a super-Earth (2 Mearth < M sin(i) < 10 Mearth) around an M dwarf adds to the growing evidence that such planets are common around very low mass stars: a third of the 20 known planets with M sin(i) < 0.1 Mjup and 3 of the 7 known planets with M sin(i) < 10 Mearth orbit an M dwarf, in contrast to just 4 of the ~300 known Jupiter-mass planets., Resubmitted to A&A after the minor modifications suggested by the referee

We report high-precision transit photometry for the recently detected planet HD 17156b. Using these new data with previously published transit photometry and radial velocity measurements, we perform a combined analysis based on a Markov Chain Monte Carlo approach. The resulting mass M_p = 3.09 (+0.22-0.17) M_Jup and radius R_p = 1.23 (+0.17-0.20) R_Jup for the planet places it at the outer edge of the density distribution of known transiting planets with rho_p = 1.66 (+1.37-0.60) rho_Jup. The obtained transit ephemeris is T_tr = 2454438.48271 (+0.00077-0.00057) + N x 21.21747 (+0.00070-0.00067) BJD. The derived plausible tidal circularization time scales for HD 17156b are larger than the age of the host star. The measured high orbital eccentricity e = 0.6719 (+0.0052-0.0063) can thus not be interpreted as the clear sign of the presence of another body in the system., Comment: 6 pages, 3 figures, 1 table. Accepted for publication in A&A

We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda=7.2+-4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented., A&A Letters (in press), 5 pages, 2 figures