S. Udry

Publications (509)271.52 Total impact

• Article: Astrometric orbit of a low-mass companion to an ultracool dwarf

  J. Sahlmann, P. F. Lazorenko, D. Segransan, E. L. Martin, D. Queloz, M. Mayor, S. Udry
  [show abstract] [hide abstract]
  ABSTRACT: Little is known about the existence of extrasolar planets around ultracool dwarfs. Furthermore, binary stars with Sun-like primaries and very low-mass binaries composed of ultracool dwarfs show differences in the distributions of mass ratio and orbital separation that can be indicative of distinct formation mechanisms. Using FORS2/VLT optical imaging for high precision astrometry we are searching for planets and substellar objects around ultracool dwarfs to investigate their multiplicity properties for very low companion masses. Here we report astrometric measurements with an accuracy of two tenths of a milli-arcsecond over two years that reveal orbital motion of the nearby L1.5 dwarf DENIS-P J082303.1-491201 located at 20.77 +/- 0.08 pc caused by an unseen companion that revolves about its host on an eccentric orbit in 246.4 +/- 1.4 days. We estimate the L1.5 dwarf to have 7.5 +/- 0.7 % of the Sun's mass that implies a companion mass of 28 +/- 2 Jupiter masses. This new system has the smallest mass ratio (0.36 +/- 0.02) of known very low-mass binaries with characterised orbits. With this discovery we demonstrate 200 micro-arcsecond astrometry over an arc-minute field and over several years that is sufficient to discover sub-Jupiter mass planets around ultracool dwarfs. We also show that the achieved parallax accuracy of < 0.4 % makes it possible to remove distance as a dominant source of uncertainty in the modelling of ultracool dwarfs.
  06/2013;
• Article: The HARPS search for southern extra-solar planets. XXXIV. A planetary system around the nearby M dwarf GJ163, with a super-Earth possibly in the habitable zone

  X. Bonfils, G. Lo Curto, A. C. M. Correia, J. Laskar, S. Udry, X. Delfosse, T. Forveille, N. Astudillo-Defru, W. Benz, F. Bouchy, [......], C. Lovis, M. Mayor, C. Moutou, D. Naef, V. Neves, F. Pepe, C. Perrier, D. Queloz, N. C. Santos, D. Ségransan
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  ABSTRACT: The meter-per-second precision achieved by today velocimeters enables the search for 1-10 M_Earth planets in the habitable zone of cool stars. This paper reports on the detection of 3 planets orbiting GJ163 (HIP19394), a M3 dwarf monitored by our ESO/HARPS search for planets. We made use of the HARPS spectrograph to collect 150 radial velocities of GJ163 over a period of 8 years. We searched the RV time series for coherent signals and found 5 distinct periodic variabilities. We investigated the stellar activity and casted doubts on the planetary interpretation for 2 signals. Before more data can be acquired we concluded that at least 3 planets are orbiting GJ163. They have orbital periods of P_b=8.632+-0.002, P_c=25.63+-0.03 and P_d=604+-8 days and minimum masses msini = 10.6+-0.6, 6.8+-0.9, and 29+-3 M_Earth, respectively. We hold our interpretations for the 2 additional signals with periods P_(e)=19.4 and P_(f)=108 days. The inner pair presents an orbital period ratio of 2.97, but a dynamical analysis of the system shows that it lays outside the 3:1 mean motion resonance. GJ163c, in particular, is a super-Earth with an equilibrium temperature of T_eq = (302+-10) (1-A)^(1/4) K and may lie in the so called habitable zone for albedo values (A=0.34-0.89) moderately higher than that of Earth (A_Earth=0.2-0.3).
  06/2013;
• Article: Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star

  A. Zurlo, A. Vigan, J. Hagelberg, S. Desidera, G. Chauvin, J. M. Almenara, K. Biazzo, M. Bonnefoy, J. C. Carson, E. Covino, P. Delorme, V. D'Orazi, R. Gratton, D. Mesa, S. Messina, C. Moutou, D. Segransan, M. Turatto, S. Udry, F. Wildi
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  ABSTRACT: As is the case for all techniques involved in the research for exoplanets, direct imaging has to take into account the probability of so-called astrophysical false positives, which are phenomena that mimic the signature of objects we are seeking. In this work we aim to present a case of a false positive found during a direct imaging survey conducted with VLT/NACO. A promising exoplanet candidate was detected around the K2-type star HD\,8049 in July 2010.Its contrast of $\Delta H$=7.05 at 1.57 arcsec allowed us to guess the presence of a 35 \MJup companion at 50 projected AU, for the nominal system age and heliocentric distance.To check whether it was gravitationally bound to the host star, as opposed to an unrelated background object, we re-observed the system one year later and concluded a high probability of a bound system. We also used radial velocity measurements of the host star, spanning a time range of $\sim$ 30 yr, to constrain the companion's mass and orbital properties, as well as to probe the host star's spectral age indicators and general spectral energy distribution. We also obtained for the companion $U$-band imaging with EFOSC and $NIR$ spectroscopy. Combining all these information we conclude that the companion of HD\,8049 is a white dwarf (WD), with temperature $T_{eff}=18800 \pm 2100$ K and mass $M_{WD}=0.56 \pm 0.08 M_{\odot}$. The significant radial velocity trend coupled with the imaging data indicate that the most probable orbit has a semimajor axis of about 50 AU.The discrepancy between the age indicators suggested against a bona-fide young star. The moderately large level of chromospheric activity and fast rotation, mimicking the properties of a young star, might be induced by the exchange of mass with the progenitor of the WD. This example demonstrates some of the challenges in determining accurate age estimates and identifications of faint companions.
  04/2013;
• Article: WASP-80b: a gas giant transiting a cool dwarf

  Amaury H. M. J. Triaud, D. R. Anderson, A. Collier Cameron, A. P. Doyle, A. Fumel, M. Gillon, C. Hellier, E. Jehin, M. Lendl, C. Lovis, P. F. L. Maxted, F. Pepe, D. Pollacco, D. Queloz, D. Segransan, B. Smalley, A. M. S. Smith, S. Udry, R. G. West, P. J. Wheatley
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  ABSTRACT: We report the discovery of a planet transiting the star WASP-80 (1SWASP J201240.26-020838.2; 2MASS J20124017-0208391; TYC 5165-481-1; BPM 80815; V=11.9, K=8.4). Our analysis shows this is a 0.55 +/- 0.04 Mjup, 0.95 +/- 0.03 Rjup gas giant on a circular 3.07 day orbit around a star with a spectral type between K7V and M0V. This system produces one of the largest transit depths so far reported, making it a worthwhile target for transmission spectroscopy. We find a large discrepancy between the v sin i inferred from stellar line broadening and the observed amplitude of the Rossiter-McLaughlin effect. This can be understood either by an orbital plane nearly perpendicular to the stellar spin or by an additional, unaccounted for source of broadening.
  03/2013;
• Article: Volatile and refractory abundances of solar analogs with planets

  J. I. González Hernández, E. Delgado-Mena, S. G. Sousa, G. Israelian, N. C. Santos, S. Udry
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  ABSTRACT: We present a detailed abundance analysis of high-quality HARPS, UVES and UES spectra of 95 solar analogs, 33 with and 62 without detected planets. These spectra have S/N > 350. We investigate the possibility that the possible presence of terrestrial planets could affect the volatile-to-refratory abundance ratios. We do not see clear differences between stars with and without planets, either in the only seven solar twins or even when considering the whole sample of 95 solar analogs in the metallicity range -0.3< [Fe/H] < 0.5 . We demonstrate that after removing the Galactic chemical evolution effects the possible differences between stars with and without planets in these samples practically disappear and the volatile-to-refractory abundance ratios are very similar to solar values. We investigate the abundance ratios of volatile and refractory elements versus the condensation temperature of this sample of solar analogs, in particular, paying a special attention to those stars harbouring super-Earth-like planets.
  02/2013;
• Article: On the functional form of the metallicity-giant planet correlation

  A. Mortier, N. C. Santos, S. Sousa, G. Israelian, M. Mayor, S. Udry
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  ABSTRACT: It is generally accepted that the presence of a giant planet is strongly dependent on the stellar metallicity. A stellar mass dependence has also been investigated, but this dependence does not seem as strong as the metallicity dependence. Even for metallicity, however, the exact form of the correlation has not been established. In this paper, we test several scenarios for describing the frequency of giant planets as a function of its host parameters. We perform this test on two volume-limited samples (from CORALIE and HARPS). By using a Bayesian analysis, we quantitatively compared the different scenarios. We confirm that giant planet frequency is indeed a function of metallicity. However, there is no statistical difference between a constant or an exponential function for stars with subsolar metallicities contrary to what has been previously stated in the literature. The dependence on stellar mass could neither be confirmed nor be discarded.
  02/2013;
• Article: The catalogue of radial velocity standard stars for Gaia I. Pre-launch release

  C. Soubiran, G. Jasniewicz, L. Chemin, F. Crifo, S. Udry, D. Hestroffer, D. Katz
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  ABSTRACT: The Radial Velocity Spectrograph (RVS) on board of Gaia needs to be calibrated using stable reference stars known in advance. The catalogue presented here has being built for that purpose. It includes 1420 radial velocity standard star candidates selected on strict criteria in order to fulfill the Gaia-RVS requirements. A large programme of ground based observations is underway since 2006 to monitor these stars and verify their stability which has to be better than 300 m/s over several years. The observations have been made on the echelle spectrographs ELODIE and SOPHIE on the 1.93-m telescope at Observatoire de Haute-Provence (OHP), NARVAL on the Telescope Bernard Lyot at Observatoire du Pic du Midi and CORALIE on the Euler-Swiss Telescope at La Silla. Data from the OHP and Geneva Observatory archives have also been retrieved as well as HARPS spectra from the ESO archive. We provide for each star a mean radial velocity in the SOPHIE scale, derived from the combination of velocities measured with those instruments, after having carefully estimated their differences of zero-points. In total 10214 radial velocity measurements have been obtained for the 1420 stars. With a mean time baseline of 6.35 years, 92.9% of the candidates fulfill a target stability criterion of 300 m/s. 343 stars are found to be constant at the level of 100 m/s over 10 years. Comparisons with the catalogues of Nidever et al.(2002) and Chubak et al.(2012) show an excellent agreement for FGK stars, with zero-point differences lower than 100 m/s and a remarkably low RMS scatter of 33 m/s in the case of Nidever et al.(2002), suggesting that the precision of the catalogue presented here is better than this value. This catalog will likely be useful for other large-scale spectroscopic surveys such as APOGEE, Gaia-ESO, HERMES and LAMOST.
  02/2013;
• Article: The HARPS search for southern extrasolar planets: XXXIII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone

  G. Lo Curto, M. Mayor, W. Benz, F. Bouchy, G. Hebrard, C. Lovis, C. Moutou, D. Naef, F. Pepe, D. Queloz, N. C. Santos, D. Segransan, S. Udry
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  ABSTRACT: The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey of ~850 nearby solar-type stars, and in the course of the past nine years we have monitored the radial velocity of HD103774, HD109271, and BD-061339. In this work we present the detection of five planets orbiting these stars, with m*sin(i) between 0.6 and 7 Neptune masses, four of which are in two multiple systems, comprising one super-Earth and one planet within the habitable zone of a late-type dwarf. Although for strategic reasons we chose efficiency over precision in this survey, we have the capability to detect planets down to the Neptune and super-Earth mass range, as well as multiple systems, provided that enough data points are made available.
  01/2013;
• Article: Searching for the signatures of terrestrial planets in F-, G-type main-sequence stars

  J. I. González Hernández, E. Delgado-Mena, S. G. Sousa, G. Israelian, N. C. Santos, V. Zh. Adibekyan, S. Udry
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  ABSTRACT: We have studied the volatile-to-refractory abundance ratios to investigate their possible relation with the low-mass planetary formation. We present a fully differential chemical abundance analysis using high-quality HARPS and UVES spectra of 61 late F- and early G-type main-sequence stars, 29 are planet hosts and 32 are stars without detected planets. As the previous sample of solar analogs, these stars slightly hotter than the Sun also provide very accurate Galactic chemical abundance trends in the metallicity range $-0.3<{\rm [Fe/H]}<0.4$. Stars with and without planets show similar mean abundance ratios. Moreover, when removing the Galactic chemical evolution effects, these mean abundance ratios, $\Delta {\rm [X/Fe]_{SUN-STARS}}$, versus condensation temperature tend to exhibit less steep trends with nearly null or slightly negative slopes. We have also analyzed a sub-sample of 26 metal-rich stars, 13 with and 13 without known planets and find the similar, although not equal, abundance pattern with negative slopes for both samples of stars with and without planets. Using stars at S/N $\ge 550$ provides equally steep abundance trends with negative slopes for both stars with and without planets. We revisit the sample of solar analogs to study the abundance patterns of these stars, in particular, 8 stars hosting super-Earth-like planets. Among these stars having very low-mass planets, only four of them reveal clear increasing abundance trends versus condensation temperature. Finally, we have compared these observed slopes with those predicted using a simple model which enables us to compute the mass of rocks which have formed terrestrial planets in each planetary system. We do not find any evidence supporting the conclusion that the volatile-to-refractory abundance ratio is related to the presence of rocky planets.
  01/2013;
• Article: Metallicity of M dwarfs III. Planet-metallicity and planet-stellar mass correlations of the HARPS GTO M dwarf sample

  V. Neves, X. Bonfils, N. C. Santos, X. Delfosse, T. Forveille, F. Allard, S. Udry
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  ABSTRACT: Aims. The aim of this work is the study of the planet-metallicity and the planet-stellar mass correlations for M dwarfs from the HARPS GTO M dwarf subsample Methods. We use a new method that takes advantage of the HARPS high-resolution spectra to increase the precision of metallicity, using previous photometric calibrations of [Fe/H] and effective temperature as starting values. Results. In this work we use our new calibration (rms = 0.08 dex) to study the planet-metallicity relation of our sample. The well-known correlation for Giant planet FGKM hosts with metallicity is present. Regarding Neptunians and smaller hosts no correlation is found but there is a hint that an anti-correlation with [Fe/H] may exist. We combined our sample with the California Planet Survey late-K and M-type dwarf sample to increase our statistics but found no new trends. We fitted a power law to the frequency histogram of the Jovian hosts for our sample and for the combined sample, f_p = C10^\alpha[Fe/H], using two different approaches: a direct bin fitting and a bayesian fitting procedure. We obtained a value for C between 0.02 and 0.04 and for \alpha between 1.26 and 2.94. Regarding stellar mass, an hypothetical correlation with planets was discovered, but was found to be the result of a detection bias.
  12/2012;
• Article: The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets

  M. Marmier, D. Ségransan, S. Udry, M. Mayor, F. Pepe, D. Queloz, C. Lovis, D. Naef, N. C. Santos, R. Alonso, [......], M. Gillon, J. Hagelberg, M. Lendl, R. A. Mardling, D. Mégevand, M. Neveu, J. Sahlmann, D. Sosnowska, M. Tewes, A. H. M. J. Triaud
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  ABSTRACT: Since 1998, a planet-search program around main sequence stars within 50 pc in the southern hemisphere, is carried out with the CORALIE echelle spectrograph at La Silla Observatory. With an observing time span of more than 14 years, the CORALIE survey is now able to unveil Jovian planets on Jupiter's period domain. This growing period-interval coverage is important regarding to formation and migration models since observational constraints are still weak for periods beyond the ice line. Long-term precise Doppler measurements with the CORALIE echelle spectrograph, together with a few additional observations made with the HARPS spectrograph on the ESO 3.6m telescope, reveal radial velocity signatures of massive planetary companions in long period orbits. In this paper we present seven new planets orbiting HD27631, HD98649, HD106515A, HD166724, HD196067, HD219077, and HD220689 together with the CORALIE orbital parameters for three already known planets around HD10647, HD30562, and HD86226. The period range of the new planetary companions goes from 2200 to 5500 days and covers a mass domain between 1 and 10.5 MJup. Surprisingly, five of them present quite high eccentricities above e>0.57. A pumping scenario by Kozai mechanism may be invoked for HD106515Ab and HD196067b which are both orbiting stars in multiple systems. As the presence of a third massive body can't be inferred from the data of HD98649b, HD166724b, and HD219077b, the origin of the eccentricity of these systems remains unknown. Except for HD10647b, no constraint on the upper mass of the planets is provided by Hipparcos astrometric data. Finally it is interesting to note that the hosts of these long period planets show no metallicity excess.
  11/2012;
• Article: WASP-77 Ab: A transiting hot Jupiter planet in a wide binary system

  P. F. L. Maxted, D. R. Anderson, A. Collier Cameron, A. P. Doyle, A. Fumel, M. Gillon, C. Hellier, E. Jehin, M. Lendl, F. Pepe, D. L. Pollacco, D. Queloz, D. Ségransan, B. Smalley, J. K. Southworth, A. M. S. Smith, A. H. M. J. Triaud, S. Udry, R. G. West
  [show abstract] [hide abstract]
  ABSTRACT: 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.
  11/2012;
• Article: WASP-71b: a bloated hot Jupiter in an 2.9-day, prograde orbit around an evolved F8 star

  A. M. S. Smith, D. R. Anderson, F. Bouchy, A. Collier Cameron, A. P. Doyle, A. Fumel, M. Gillon, G. Hébrard, C. Hellier, E. Jehin, [......], C. Moutou, F. Pepe, D. Pollacco, D. Queloz, A. Santerne, D. Segransan, B. Smalley, A. H. M . J. Triaud, S. Udry, R. G. West
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  ABSTRACT: We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.258 +/- 0.072 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b, is larger than Jupiter (1.50 +/- 0.11 RJup), but less dense (0.67 +/- 0.14 {\rho}Jup). We also report spectroscopic observations made during transit with the CORALIE spectrograph, which allow us to detect the Rossiter-McLaughlin effect. We determine the sky-projected angle between the stellar-spin and planetary-orbit axes to be {\lambda} = 19.8 +/- 9.9 degrees.
  11/2012;
• Source

  Available from: F. Faedi

  Article: WASP-52b, WASP-58b, WASP-59b, and WASP-60b: four new transiting close-in giant planets

  G. Hebrard, A. Collier Cameron, D. J. A. Brown, R. F. Diaz, F. Faedi, B. Smalley, D. R. Anderson, D. Armstrong, S. C. C. Barros, J. Bento, [......], A. Santerne, I. Skillen, J. Southworth, J. Tregloan-Reed, A. H. M. J. Triaud, S. Udry, M. Vanhuysse, C. A. Watson, R. G. West, P. J. Wheatley
  [show abstract] [hide abstract]
  ABSTRACT: We present the discovery of four new transiting hot jupiters, detected mainly from SuperWASP-North and SOPHIE observations. These new planets, WASP-52b, WASP-58b, WASP-59b, and WASP-60b, have orbital periods ranging from 1.7 to 7.9 days, masses between 0.46 and 0.94 M_Jup, and radii between 0.73 and 1.49 R_Jup. Their G1 to K5 dwarf host stars have V magnitudes in the range 11.7-13.0. The depths of the transits are between 0.6 and 2.7%, depending on the target. With their large radii, WASP-52b and 58b are new cases of low-density, inflated planets, whereas WASP-59b is likely to have a large, dense core. WASP-60 shows shallow transits. In the case of WASP-52 we also detected the Rossiter-McLaughlin anomaly via time-resolved spectroscopy of a transit. We measured the sky-projected obliquity lambda = 24 (+17/-9) degrees, indicating that WASP-52b orbits in the same direction as its host star is rotating and that this prograde orbit is slightly misaligned with the stellar equator. These four new planetary systems increase our statistics on hot jupiters, and provide new targets for follow-up studies.
  11/2012;
• Article: WASP-64b and WASP-72b: two new transiting highly irradiated giant planets

  M. Gillon, D. R. Anderson, A. Collier-Cameron, A. P. Doyle, A. Fumel, C. Hellier, E. Jehin, M. Lendl, P. F. L. Maxted, J. Montalban, F. Pepe, D. Pollacco, D. Queloz, D. Segransan, A. M. S. Smith, B. Smalley, J. Southworth, A. H. M. J. Triaud, S. Udry, R. G. West
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  ABSTRACT: We report the discovery by the WASP transit survey of two new highly irradiated giant planets transiting moderately bright stars. WASP-64b is slightly more massive (1.271+-0.068 M_Jup) and larger (1.271+-0.039 R_Jup) than Jupiter, and is in very-short (a=0.02648+-0.00024 AU, P=1.5732918+-0.0000015 days) circular orbit around a V=12.3 G7-type dwarf (1.004+-0.028 M_Sun, 1.058+-0.025 R_Sun, Teff=5500+-150 K). Its size is typical of hot Jupiters with similar masses. WASP-72b has also a mass a bit higher than Jupiter's (1.461-0.056+0.059 M_Jup) and orbits very close (0.03708+-0.00050 AU, P=2.2167421+-0.0000081 days) to a bright (V=9.6) and moderately evolved F7-type star (1.386+-0.055 M_Sun, 1.98+-0.24 R_Sun, Teff=6250+-100 K). Despite its extreme irradiation (about 5.5 10^9 erg/s/cm^2), WASP-72b has a moderate size (1.27+-0.20 R_Jup) that could suggest a significant enrichment in heavy elements. Nevertheless, the errors on its physical parameters are still too high to draw any strong inference on its internal structure or its possible peculiarity.
  10/2012;
• Source

  Available from: F. Faedi

  Article: WASP-54b, WASP-56b and WASP-57b: Three new sub-Jupiter mass planets from SuperWASP

  F. Faedi, D. Pollacco, S. C. C. Barros, D. Brown, A. Collier Cameron, A. P. Doyle, R. Enoch, M. Gillon, Y. Gomez Maqueo Chew, G. Hebrard, [......], G. R. M. Miller, C. Moutou, A. J. Norton, N. Parley, D. Queloz, A. Santerne, I. Skillen, A. M. S. Smith, S. Udry, C. Watson
  [show abstract] [hide abstract]
  ABSTRACT: We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey: WASP-54b is a heavily bloated planet of mass 0.636$^{+0.025}_{-0.024}$ \mj and radius 1.653$^{+0.090}_{-0.083}$ \rj. It orbits a F9 star, evolving off the main sequence, every 3.69 days. Our MCMC fit of the system yields a slightly eccentric orbit ($e=0.067^{+0.033}_{-0.025}$) for WASP-54b. We investigated further the veracity of our detection of the eccentric orbit for WASP-54b, and we find that it could be real. However, given the brightness of WASP-54 V=10.42 magnitudes, we encourage observations of a secondary eclipse to draw robust conclusions on both the orbital eccentricity and the thermal structure of the planet. WASP-56b and WASP-57b have masses of 0.571$^{+0.034}_{-0.035}$ \mj and $0.672^{+0.049}_{-0.046}$ \mj, respectively; and radii of $1.092^{+0.035}_{-0.033}$ \rj for WASP-56b and $0.916^{+0.017}_{-0.014}$ \rj for WASP-57b. They orbit main sequence stars of spectral type G6 every 4.67 and 2.84 days, respectively. WASP-56b and WASP-57b show no radius anomaly and a high density possibly implying a large core of heavy elements; possibly as high as $\sim$50 M$_{\oplus}$ in the case of WASP-57b. However, the composition of the deep interior of exoplanets remain still undetermined. Thus, more exoplanet discoveries such as the ones presented in this paper, are needed to understand and constrain giant planets' physical properties.
  10/2012;
• Article: Gearing up the SPHERE

  M Kasper, J -L Beuzit, M Feldt, K Dohlen, D Mouillet, P Puget, F Wildi, L Abe, A Baruffolo, P Baudoz, [......], N Schuhler, A Sevin, R Siebenmorgen, C Soenke, E Stadler, M Suarez, M Turatto, S Udry, A Vigan, G Zins
  The Messenger. 09/2012; 149:17-21.
• Conference Proceeding: Harps-N: the new planet hunter at TNG

  R Cosentino, C Lovis, F Pepe, A Collier Cameron, D ~W Latham, E Molinari, S Udry, N Bezawada, M Black, A Born, [......], L Riverol, J San Juan, D Sasselov, D Segransan, A Sozzetti, D Sosnowska, B Stobie, A Szentgyorgyi, A Vick, L Weber
  Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 09/2012
• Source

  Available from: Isabelle Boisse

  Dataset: The_SOPHIE_search_for_northern_extrasolar_planets_V_Follow-up_of_ELODIE_candidates_Jupiter-analogs_around_Sun-like_stars

  I. Boisse, F. Pepe, C. Perrier, D. Queloz, X. Bonfils, F. Bouchy, N. C. Santos, L. Arnold, J. -L. Beuzit, R. F. Dìaz, [......], G. Hébrard, A. -M. Lagrange, C. Lovis, M. Mayor, C. Moutou, D. Naef, A. Santerne, D. Ségransan, J. -P. Sivan, S. Udry
• Article: A hot Uranus transiting the nearby M dwarf GJ3470. Detected with HARPS velocimetry. Captured in transit with TRAPPIST photometry

  X. Bonfils, M. Gillon, S. Udry, D. Armstrong, F. Bouchy, X. Delfosse, T. Forveille, E. Jehin, M. Lendl, C. Lovis, M. Mayor, J. McCormac, V. Neves, F. Pepe, C. Perrier, D. Pollaco, D. Queloz, N. C. Santos
  [show abstract] [hide abstract]
  ABSTRACT: We report on the discovery of GJ3470b, a transiting hot Uranus of mass m_p = 14.0+-1.8 Mearth, radius R_p = 4.2+-0.6 Rearth and period P=3.3371+-0.0002 day. Its host star is a nearby (d=25.2+-2.9pc) M1.5 dwarf of mass M_s=0.54+-0.07 Msol and radius R_s=0.50+-0.06 Rsol. The detection originates from a radial-velocity campaign with HARPS that focused on the search for short-period planets orbiting M dwarfs. Once the planet was discovered and the transit-search window narrowed to about 10% of an orbital period, a photometric search started with TRAPPIST and quickly detected the ingress of the planet. Additional observations with TRAPPIST, EulerCam and NITES definitely confirmed the transiting nature of GJ3470b and allow for the determination of its true mass and radius. The star's visible or infrared brightness (V=12.3, K=8.0 mag), together with a large eclipse depth D=0.57+-0.05%, ranks GJ3470b among the most favorable planets for follow-up characterizations.
  06/2012;