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Rodrigo F. Díaz - One of the best experts on this subject based on the ideXlab platform.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial Velocity monitoring with SOPHIE star
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Elaine Simpson, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets, we have acquired new Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring a gas giant on a close orbit (orbital period of 1.09 and 2.24 d, respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049 +/- 0.015 for WASP-12b and 0.091 +/- 0.003 for WASP-14b. Since then, measurements of the occultation of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos omega) was close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements show that the Radial Velocity data are compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e = 0.017+0.015(-0.010). In contrast, we confirm the orbital eccentricity of WASP-14b, and refine its value to e = 0.0877 +/- 0.0030, a 10 Sigma detection. WASP-14b is thus the closest presently known planet with a confirmed eccentric orbit.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial-Velocity monitoring with SOPHIE
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, E. K. Simpson, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets -- designed to measure orbital eccentricities, spin-orbit alignments and further planetary companions -- we have acquired Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring gas giants on close orbits (orbital period of 1.09 and 2.24 days respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049+-0.015 for WASP-12 and 0.091+-0.003 for WASP-14. Since then, measurements of the secondary eclipse of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos w) was very close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements confirm that the initial eccentricity detection could be spurious, and show that the Radial Velocity data is compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e=0.017 (+0.015-0.011). By contrast, we confirm the orbital eccentricity of WASP-14, and refine its value to e=0.088+-0.003. WASP-14 is thus the closest presently known planet with a confirmed eccentric orbit.
Raphaelle D Haywood - One of the best experts on this subject based on the ideXlab platform.
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three years of sun as a star Radial Velocity observations on the approach to solar minimum
Monthly Notices of the Royal Astronomical Society, 2019Co-Authors: Collier A Cameron, Raphaelle D Haywood, A Mortier, David F Phillips, X Dumusque, Nicholas Langellier, C A Watson, H M Cegla, J Costes, D CharbonneauAbstract:The time-variable Velocity fields of solar-type stars limit the precision of Radial-Velocity determinations of their planets' masses, obstructing detection of Earth twins. Since 2015 July we have been monitoring disc-integrated sunlight in daytime using a purpose-built solar telescope and fibre feed to the HARPS-N stellar Radial-Velocity spectrometer. We present and analyse the solar Radial-Velocity measurements and cross-correlation function (CCF) parameters obtained in the first 3 years of observation, interpreting them in the context of spatially-resolved solar observations. We describe a Bayesian mixture-model approach to automated data-quality monitoring. We provide dynamical and daily differential-extinction corrections to place the Radial velocities in the heliocentric reference frame, and the CCF shape parameters in the sidereal frame. We achieve a photon-noise limited Radial-Velocity precision better than 0.43 m s$^{-1}$ per 5-minute observation. The day-to-day precision is limited by zero-point calibration uncertainty with an RMS scatter of about 0.4 m s$^{-1}$. We find significant signals from granulation and solar activity. Within a day, granulation noise dominates, with an amplitude of about 0.4 m s$^{-1}$ and an autocorrelation half-life of 15 minutes. On longer timescales, activity dominates. Sunspot groups broaden the CCF as they cross the solar disc. Facular regions temporarily reduce the intrinsic asymmetry of the CCF. The Radial-Velocity increase that accompanies an active-region passage has a typical amplitude of 5 m s$^{-1}$ and is correlated with the line asymmetry, but leads it by 3 days. Spectral line-shape variability thus shows promise as a proxy for recovering the true Radial Velocity.
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long term Radial Velocity variations of the sun as a star the harps view
Astronomy and Astrophysics, 2016Co-Authors: A Lanza, P Molaro, L Monaco, Raphaelle D HaywoodAbstract:Context. Stellar Radial velocities play a fundamental role in the discovery of extrasolar planets and the measurement of their physical parameters as well as in the study of stellar physical properties. Aims. We investigate the impact of the solar activity on the Radial Velocity of the Sun using the HARPS spectrograph to obtain measurements that can be directly compared with those acquired in the extrasolar planet search programmes. Methods. We used the Moon, the Galilean satellites, and several asteroids as reflectors to measure the Radial Velocity of the Sun as a star and correlated this Velocity with disc-integrated chromospheric and magnetic indexes of solar activity that are similar to stellar activity indexes. We discuss in detail the systematic e ects that a ect our measurements and the methods to account for them. Results. We find that the Radial Velocity of the Sun as a star is positively correlated with the level of its chromospheric activity at 95 percent significance level. The amplitude of the long-term variation measured in the 2006 2014 period is 4:98 1:44 m/s, which is in good agreement with model predictions. The standard deviation of the residuals obtained by subtracting a linear best fit is 2.82 m/s and is due to the rotation of the reflecting bodies and the intrinsic variability of the Sun on timescales shorter than the activity cycle. A correlation with a lower significance is detected between the Radial Velocity and the mean absolute value of the line-of-sight photospheric magnetic field flux density. Conclusions. Our results confirm similar correlations found in other late-type main-sequence stars and provide support to the predictions of Radial Velocity variations induced by stellar activity based on current models.
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long term Radial Velocity variations of the sun as a star the harps view
arXiv: Earth and Planetary Astrophysics, 2016Co-Authors: A Lanza, P Molaro, L Monaco, Raphaelle D HaywoodAbstract:Stellar Radial velocities play a fundamental role in the discovery of extrasolar planets and the measurement of their physical parameters as well as in the study of stellar physical properties. We investigate the impact of the solar activity on the Radial Velocity of the Sun using the HARPS spectrograph to obtain measurements that can be directly compared with those acquired in the extrasolar planet search programs. We use the Moon, the Galilean satellites, and several asteroids as reflectors to measure the Radial Velocity of the Sun as a star and correlate it with disc-integrated chromospheric and magnetic indexes of solar activity that are similar to stellar activity indexes. We discuss in detail the systematic effects that affect our measurements and the methods to account for them. We find that the Radial Velocity of the Sun as a star is positively correlated with the level of its chromospheric activity at about 95 percent significance level. The amplitude of the long-term variation measured in the 2006-2014 period is 4.98 \pm 1.44 m/s, in good agreement with model predictions. The standard deviation of the residuals obtained by subtracting a linear best fit is 2.82 m/s and is due to the rotation of the reflecting bodies and the intrinsic variability of the Sun on timescales shorter than the activity cycle. A correlation with a lower significance is detected between the Radial Velocity and the mean absolute value of the line-of-sight photospheric magnetic field flux density. Our results confirm similar correlations found in other late-type main-sequence stars and provide support to the predictions of Radial Velocity variations induced by stellar activity based on current models.
Nawal Husnoo - One of the best experts on this subject based on the ideXlab platform.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial Velocity monitoring with SOPHIE star
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Elaine Simpson, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets, we have acquired new Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring a gas giant on a close orbit (orbital period of 1.09 and 2.24 d, respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049 +/- 0.015 for WASP-12b and 0.091 +/- 0.003 for WASP-14b. Since then, measurements of the occultation of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos omega) was close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements show that the Radial Velocity data are compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e = 0.017+0.015(-0.010). In contrast, we confirm the orbital eccentricity of WASP-14b, and refine its value to e = 0.0877 +/- 0.0030, a 10 Sigma detection. WASP-14b is thus the closest presently known planet with a confirmed eccentric orbit.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial-Velocity monitoring with SOPHIE
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, E. K. Simpson, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets -- designed to measure orbital eccentricities, spin-orbit alignments and further planetary companions -- we have acquired Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring gas giants on close orbits (orbital period of 1.09 and 2.24 days respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049+-0.015 for WASP-12 and 0.091+-0.003 for WASP-14. Since then, measurements of the secondary eclipse of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos w) was very close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements confirm that the initial eccentricity detection could be spurious, and show that the Radial Velocity data is compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e=0.017 (+0.015-0.011). By contrast, we confirm the orbital eccentricity of WASP-14, and refine its value to e=0.088+-0.003. WASP-14 is thus the closest presently known planet with a confirmed eccentric orbit.
Isabelle Boisse - One of the best experts on this subject based on the ideXlab platform.
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sophie first results of an octagonal section fiber for high precision Radial Velocity measurements
arXiv: Instrumentation and Methods for Astrophysics, 2012Co-Authors: Isabelle Boisse, F Bouchy, R F Diaz, G Hebrard, L Arnold, X Delfosse, S PerruchotAbstract:High-precision spectrographs play a key role in exoplanet searches and Doppler asteroseismology using the Radial Velocity technique. The 1 m/s level of precision requires very high stability and uniformity of the illumination of the spectrograph. In fiber-fed spectrographs such as SOPHIE, the fiber-link scrambling properties are one of the main conditions for high precision. To significantly improve the Radial Velocity precision of the SOPHIE spectrograph, which was limited to 5-6 m/s, we implemented a piece of octagonal-section fiber in the fiber link. We present here the scientific validation of the upgrade of this instrument, demonstrating a real improvement. The upgraded instrument, renamed SOPHIE+, reaches Radial Velocity precision in the range of 1-2 m/s. It is now fully efficient for the detection of low-mass exoplanets down to 5-10 Earth mass and for the identification of acoustic modes down to a few tens of cm/s.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial Velocity monitoring with SOPHIE star
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Elaine Simpson, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets, we have acquired new Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring a gas giant on a close orbit (orbital period of 1.09 and 2.24 d, respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049 +/- 0.015 for WASP-12b and 0.091 +/- 0.003 for WASP-14b. Since then, measurements of the occultation of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos omega) was close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements show that the Radial Velocity data are compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e = 0.017+0.015(-0.010). In contrast, we confirm the orbital eccentricity of WASP-14b, and refine its value to e = 0.0877 +/- 0.0030, a 10 Sigma detection. WASP-14b is thus the closest presently known planet with a confirmed eccentric orbit.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial-Velocity monitoring with SOPHIE
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, E. K. Simpson, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets -- designed to measure orbital eccentricities, spin-orbit alignments and further planetary companions -- we have acquired Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring gas giants on close orbits (orbital period of 1.09 and 2.24 days respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049+-0.015 for WASP-12 and 0.091+-0.003 for WASP-14. Since then, measurements of the secondary eclipse of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos w) was very close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements confirm that the initial eccentricity detection could be spurious, and show that the Radial Velocity data is compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e=0.017 (+0.015-0.011). By contrast, we confirm the orbital eccentricity of WASP-14, and refine its value to e=0.088+-0.003. WASP-14 is thus the closest presently known planet with a confirmed eccentric orbit.
Guillaume Hébrard - One of the best experts on this subject based on the ideXlab platform.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial Velocity monitoring with SOPHIE star
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Elaine Simpson, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets, we have acquired new Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring a gas giant on a close orbit (orbital period of 1.09 and 2.24 d, respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049 +/- 0.015 for WASP-12b and 0.091 +/- 0.003 for WASP-14b. Since then, measurements of the occultation of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos omega) was close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements show that the Radial Velocity data are compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e = 0.017+0.015(-0.010). In contrast, we confirm the orbital eccentricity of WASP-14b, and refine its value to e = 0.0877 +/- 0.0030, a 10 Sigma detection. WASP-14b is thus the closest presently known planet with a confirmed eccentric orbit.
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Orbital eccentricity of WASP-12 and WASP-14 from new Radial-Velocity monitoring with SOPHIE
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Nawal Husnoo, Guillaume Hébrard, François Bouchy, Frederic Pont, Tsevi Mazeh, Claire Moutou, Luc Arnold, Isabelle Boisse, E. K. Simpson, Rodrigo F. DíazAbstract:As part of the long-term Radial Velocity monitoring of known transiting planets -- designed to measure orbital eccentricities, spin-orbit alignments and further planetary companions -- we have acquired Radial Velocity data for the two transiting systems WASP-12 and WASP-14, each harbouring gas giants on close orbits (orbital period of 1.09 and 2.24 days respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049+-0.015 for WASP-12 and 0.091+-0.003 for WASP-14. Since then, measurements of the secondary eclipse of WASP-12 in the infrared have indicated that one projection of the eccentricity (e cos w) was very close to zero, casting doubt on the eccentricity from the initial Radial Velocity orbit. Our measurements confirm that the initial eccentricity detection could be spurious, and show that the Radial Velocity data is compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the Radial Velocity and photometric data gives e=0.017 (+0.015-0.011). By contrast, we confirm the orbital eccentricity of WASP-14, and refine its value to e=0.088+-0.003. WASP-14 is thus the closest presently known planet with a confirmed eccentric orbit.