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F Bouchy - One of the best experts on this subject based on the ideXlab platform.
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characterization of the k2 18 multi Planetary System with harps a habitable zone super earth and discovery of a second warm super earth on a non coplanar orbit
Astronomy and Astrophysics, 2017Co-Authors: X Bonfils, X Delfosse, F Bouchy, Ryan Cloutier, N Astudillodefru, Rene Doyon, J M Almenara, Bjorn Benneke, D EhrenreichAbstract:Aims. The bright M2.5 dwarf K2-18 ( M s = 0.36 M ⊙ , R s = 0.41 R ⊙ ) at 34 pc is known to host a transiting super-Earth-sized planet orbiting within the star’s habitable zone; K2-18b. Given the superlative nature of this System for studying an exoPlanetary atmosphere receiving similar levels of insolation as the Earth, we aim to characterize the planet’s mass which is required to interpret atmospheric properties and infer the planet’s bulk composition. Methods. We have obtained precision radial velocity measurements with the HARPS spectrograph. We then coupled those measurements with the K2 photometry to jointly model the observed radial velocity variation with Planetary signals and a correlated stellar activity model based on Gaussian process regression. Results. We measured the mass of K2-18b to be 8.0 ± 1.9 M ⊕ with a bulk density of 3.3 ± 1.2 g/cm 3 which may correspond to a predominantly rocky planet with a significant gaseous envelope or an ocean planet with a water mass fraction ≳50%. We also find strong evidence for a second, warm super-Earth K2-18c ( m p,c sin i c = 7.5 ± 1.3 M ⊕ ) at approximately nine days with a semi-major axis ~ 2.4 times smaller than the transiting K2-18b. After re-analyzing the available light curves of K2-18 we conclude that K2-18c is not detected in transit and therefore likely has an orbit that is non-coplanar with the orbit of K2-18b although only a small mutual inclination is required for K2-18c to miss a transiting configuration; | Δ i | ~ 1−2°. A suite of dynamical integrations are performed to numerically confirm the System’s dynamical stability. By varying the simulated orbital eccentricities of the two planets, dynamical stability constraints are used as an additional prior on each planet’s eccentricity posterior from which we constrain e b e c Conclusions. The discovery of the inner planet K2-18c further emphasizes the prevalence of multi-planet Systems around M dwarfs. The characterization of the density of K2-18b reveals that the planet likely has a thick gaseous envelope which, along with its proximity to the solar System, makes the K2-18 Planetary System an interesting target for the atmospheric study of an exoplanet receiving Earth-like insolation.
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characterization of the k2 18 multi Planetary System with harps a habitable zone super earth and discovery of a second warm super earth on a non coplanar orbit
arXiv: Earth and Planetary Astrophysics, 2017Co-Authors: X Bonfils, X Delfosse, F Bouchy, Ryan Cloutier, N Astudillodefru, Rene Doyon, J M Almenara, Bjorn Benneke, D EhrenreichAbstract:The bright M dwarf K2-18 at 34 pc is known to host a transiting super-Earth-sized planet orbiting within the star's habitable zone; K2-18b. Given the superlative nature of this System for studying an exoPlanetary atmosphere receiving similar levels of insolation as the Earth, we aim to characterize the planet's mass which is required to interpret atmospheric properties and infer the planet's bulk composition. We obtain precision radial velocity measurements with the HARPS spectrograph and couple those measurements with the K2 photometry to jointly model the observed radial velocity variation with Planetary signals and a radial velocity jitter model based on Gaussian process regression. We measure the mass of K2-18b to be $8.0 \pm 1.9$ M$_{\oplus}$ with a bulk density of $3.7 \pm 0.9$ g/cm$^3$ which may correspond to a predominantly rocky planet with a significant gaseous envelope or an ocean planet with a water mass fraction $\gtrsim 50$%. We also find strong evidence for a second, warm super-Earth K2-18c at $\sim 9$ days with a semi-major axis 2.4 times smaller than the transiting K2-18b. After re-analyzing the available light curves of K2-18 we conclude that K2-18c is not detected in transit and therefore likely has an orbit that is non-coplanar with K2-18b. A suite of dynamical integrations with varying simulated orbital eccentricities of the two planets are used to further constrain each planet's eccentricity posterior from which we measure $e_b < 0.43$ and $e_c < 0.47$ at 99% confidence. The discovery of the inner planet K2-18c further emphasizes the prevalence of multi-planet Systems around M dwarfs. The characterization of the density of K2-18b reveals that the planet likely has a thick gaseous envelope which along with its proximity to the Solar System makes the K2-18 Planetary System an interesting target for the atmospheric study of an exoplanet receiving Earth-like insolation.
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the corot 7 Planetary System two orbiting super earths
Astronomy and Astrophysics, 2009Co-Authors: D Queloz, F Bouchy, C Moutou, A P Hatzes, G Hebrard, R Alonso, M Auvergne, A Baglin, M BarbieriAbstract:We report on an intensive observational campaign carried out with HARPS at the 3.6 m telescope at La Silla on the star CoRoT-7. Additional simultaneous photometric measurements carried out with the Euler Swiss telescope have demonstrated that the observed radial velocity variations are dominated by rotational modulation from cool spots on the stellar surface. Several approaches were used to extract the radial velocity signal of the planet(s) from the stellar activity signal. First, a simple pre-whitening procedure was employed to find and subsequently remove periodic signals from the complex frequency structure of the radial velocity data. The dominant frequency in the power spectrum was found at 23 days, which corresponds to the rotation period of CoRoT-7. The 0.8535 day period of CoRoT-7b Planetary candidate was detected with an amplitude of 3.3 m s −1 . Most other frequencies, some with amplitudes larger than the CoRoT-7b signal, are most likely associated with activity. A second approach used harmonic decomposition of the rotational period and up to the first three harmonics to filter out the activity signal from radial velocity variations caused by orbiting planets. After correcting the radial velocity data for activity, two periodic signals are detected: the CoRoT-7b transit period and a second one with a period of 3.69 days and an amplitude of 4 m s −1 . This second signal was also found in the pre-whitening analysis. We attribute the second signal to a second, more remote planet CoRoT-7c . The orbital solution of both planets is compatible with circular orbits. The mass of CoRoT-7b is 4.8 ± 0. 8( M⊕) and that of CoRoT-7c is 8.4 ± 0. 9( M⊕), assuming both planets are on coplanar orbits. We also investigated the false positive scenario of a blend by a faint stellar binary, and this may be rejected by the stability of the bisector on a nightly scale. According to their masses both planets belong to the super-Earth planet category. The average density of CoRoT-7b is ρ = 5.6 ± 1. 3gc m −3 , similar to the Earth. The CoRoT-7 Planetary System provides us with the first insight into the physical nature of short period super-Earth planets recently detected by radial velocity surveys. These planets may be denser than Neptune and therefore likely made of rocks like the Earth, or a mix of water ice and rocks.
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spin orbit misalignment in the hd 80606 Planetary System
Astronomy and Astrophysics, 2009Co-Authors: F Pont, X Bonfils, F Bouchy, C Moutou, G Hebrard, D Ehrenreich, Jonathan Irwin, T Guillot, S Aigrain, Zachory K BertaAbstract:We recently reported the photometric and spectroscopic detection of the primary transit of the 111-day-period, eccentric extra-solar planet HD 80606b, at Observatoire de Haute-Provence, France. The whole egress of the primary transit and a section of its central part were observed, allowing the measurement of the Planetary radius, and evidence for a spin-orbit misalignment through the observation of the Rossiter-McLaughlin anomaly. The ingress not having been observed for this long-duration transit, uncertainties remained in the parameters of the System. We present here a refined, combined analysis of our photometric and spectroscopic data, together with further published radial velocities, ground-based photometry, and Spitzer photometry around the secondary eclipse, as well as new photometric measurements of HD 80606 acquired at Mount Hopkins, Arizona, just before the beginning of the primary transit. Although the transit is not detected in those new data, they provide an upper limit for the transit duration, which narrows down the possible behaviour of the Rossiter-McLaughlin anomaly in the unobserved part of the transit. We analyse the whole data with a Bayesian approach using a Markov-chain Monte Carlo integration on all available information. We find Rp = 0.98 ± 0.03RJup for the Planetary radius, and a total primary transit duration of 11.9 ± 1.3 h from first to fourth contact. Our analysis reinforces the hypothesis of spin-orbit misalignment in this System (alignment excluded at >95% level), with a positive projected angle between the Planetary orbital axis and the stellar rotation (median solution λ ∼ 50 ◦ ). As HD 80606 is a component of a binary System, the peculiar orbit of its planet could result from a Kozai mechanism.
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the harps search for southern extra solar planets xviii an earth mass planet in the gj 581 Planetary System
arXiv: Earth and Planetary Astrophysics, 2009Co-Authors: M Mayor, Hervé Beust, X Bonfils, T Forveille, X Delfosse, S Udry, Jeanloup Bertaux, F Bouchy, Christophe LovisAbstract:The GJ 581 Planetary System was already known to harbour three planets, including two super-Earths planets which straddle its habitable zone. We report here the detection of an additional planet -- GJ 581e -- with a minimum mass of 1.9 M_earth. With a period of 3.15 days, it is the innermost planet of the System and has a ~5% transit probability. We also correct our previous confusion of the orbital period of GJ 581d (the outermost planet) with a one-year alias, thanks to an extended time span and many more measurements. The revised period is 66.8 days, and locates the semi-major axis inside the habitable zone of the low mass star. The dynamical stability of the 4-planet System imposes an upper bound on the orbital plane inclination. The planets cannot be more massive than approximately 1.6 times their minimum mass.
X Bonfils - One of the best experts on this subject based on the ideXlab platform.
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characterization of the k2 18 multi Planetary System with harps a habitable zone super earth and discovery of a second warm super earth on a non coplanar orbit
Astronomy and Astrophysics, 2017Co-Authors: X Bonfils, X Delfosse, F Bouchy, Ryan Cloutier, N Astudillodefru, Rene Doyon, J M Almenara, Bjorn Benneke, D EhrenreichAbstract:Aims. The bright M2.5 dwarf K2-18 ( M s = 0.36 M ⊙ , R s = 0.41 R ⊙ ) at 34 pc is known to host a transiting super-Earth-sized planet orbiting within the star’s habitable zone; K2-18b. Given the superlative nature of this System for studying an exoPlanetary atmosphere receiving similar levels of insolation as the Earth, we aim to characterize the planet’s mass which is required to interpret atmospheric properties and infer the planet’s bulk composition. Methods. We have obtained precision radial velocity measurements with the HARPS spectrograph. We then coupled those measurements with the K2 photometry to jointly model the observed radial velocity variation with Planetary signals and a correlated stellar activity model based on Gaussian process regression. Results. We measured the mass of K2-18b to be 8.0 ± 1.9 M ⊕ with a bulk density of 3.3 ± 1.2 g/cm 3 which may correspond to a predominantly rocky planet with a significant gaseous envelope or an ocean planet with a water mass fraction ≳50%. We also find strong evidence for a second, warm super-Earth K2-18c ( m p,c sin i c = 7.5 ± 1.3 M ⊕ ) at approximately nine days with a semi-major axis ~ 2.4 times smaller than the transiting K2-18b. After re-analyzing the available light curves of K2-18 we conclude that K2-18c is not detected in transit and therefore likely has an orbit that is non-coplanar with the orbit of K2-18b although only a small mutual inclination is required for K2-18c to miss a transiting configuration; | Δ i | ~ 1−2°. A suite of dynamical integrations are performed to numerically confirm the System’s dynamical stability. By varying the simulated orbital eccentricities of the two planets, dynamical stability constraints are used as an additional prior on each planet’s eccentricity posterior from which we constrain e b e c Conclusions. The discovery of the inner planet K2-18c further emphasizes the prevalence of multi-planet Systems around M dwarfs. The characterization of the density of K2-18b reveals that the planet likely has a thick gaseous envelope which, along with its proximity to the solar System, makes the K2-18 Planetary System an interesting target for the atmospheric study of an exoplanet receiving Earth-like insolation.
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characterization of the k2 18 multi Planetary System with harps a habitable zone super earth and discovery of a second warm super earth on a non coplanar orbit
arXiv: Earth and Planetary Astrophysics, 2017Co-Authors: X Bonfils, X Delfosse, F Bouchy, Ryan Cloutier, N Astudillodefru, Rene Doyon, J M Almenara, Bjorn Benneke, D EhrenreichAbstract:The bright M dwarf K2-18 at 34 pc is known to host a transiting super-Earth-sized planet orbiting within the star's habitable zone; K2-18b. Given the superlative nature of this System for studying an exoPlanetary atmosphere receiving similar levels of insolation as the Earth, we aim to characterize the planet's mass which is required to interpret atmospheric properties and infer the planet's bulk composition. We obtain precision radial velocity measurements with the HARPS spectrograph and couple those measurements with the K2 photometry to jointly model the observed radial velocity variation with Planetary signals and a radial velocity jitter model based on Gaussian process regression. We measure the mass of K2-18b to be $8.0 \pm 1.9$ M$_{\oplus}$ with a bulk density of $3.7 \pm 0.9$ g/cm$^3$ which may correspond to a predominantly rocky planet with a significant gaseous envelope or an ocean planet with a water mass fraction $\gtrsim 50$%. We also find strong evidence for a second, warm super-Earth K2-18c at $\sim 9$ days with a semi-major axis 2.4 times smaller than the transiting K2-18b. After re-analyzing the available light curves of K2-18 we conclude that K2-18c is not detected in transit and therefore likely has an orbit that is non-coplanar with K2-18b. A suite of dynamical integrations with varying simulated orbital eccentricities of the two planets are used to further constrain each planet's eccentricity posterior from which we measure $e_b < 0.43$ and $e_c < 0.47$ at 99% confidence. The discovery of the inner planet K2-18c further emphasizes the prevalence of multi-planet Systems around M dwarfs. The characterization of the density of K2-18b reveals that the planet likely has a thick gaseous envelope which along with its proximity to the Solar System makes the K2-18 Planetary System an interesting target for the atmospheric study of an exoplanet receiving Earth-like insolation.
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spin orbit misalignment in the hd 80606 Planetary System
Astronomy and Astrophysics, 2009Co-Authors: F Pont, X Bonfils, F Bouchy, C Moutou, G Hebrard, D Ehrenreich, Jonathan Irwin, T Guillot, S Aigrain, Zachory K BertaAbstract:We recently reported the photometric and spectroscopic detection of the primary transit of the 111-day-period, eccentric extra-solar planet HD 80606b, at Observatoire de Haute-Provence, France. The whole egress of the primary transit and a section of its central part were observed, allowing the measurement of the Planetary radius, and evidence for a spin-orbit misalignment through the observation of the Rossiter-McLaughlin anomaly. The ingress not having been observed for this long-duration transit, uncertainties remained in the parameters of the System. We present here a refined, combined analysis of our photometric and spectroscopic data, together with further published radial velocities, ground-based photometry, and Spitzer photometry around the secondary eclipse, as well as new photometric measurements of HD 80606 acquired at Mount Hopkins, Arizona, just before the beginning of the primary transit. Although the transit is not detected in those new data, they provide an upper limit for the transit duration, which narrows down the possible behaviour of the Rossiter-McLaughlin anomaly in the unobserved part of the transit. We analyse the whole data with a Bayesian approach using a Markov-chain Monte Carlo integration on all available information. We find Rp = 0.98 ± 0.03RJup for the Planetary radius, and a total primary transit duration of 11.9 ± 1.3 h from first to fourth contact. Our analysis reinforces the hypothesis of spin-orbit misalignment in this System (alignment excluded at >95% level), with a positive projected angle between the Planetary orbital axis and the stellar rotation (median solution λ ∼ 50 ◦ ). As HD 80606 is a component of a binary System, the peculiar orbit of its planet could result from a Kozai mechanism.
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the harps search for southern extra solar planets xviii an earth mass planet in the gj 581 Planetary System
arXiv: Earth and Planetary Astrophysics, 2009Co-Authors: M Mayor, Hervé Beust, X Bonfils, T Forveille, X Delfosse, S Udry, Jeanloup Bertaux, F Bouchy, Christophe LovisAbstract:The GJ 581 Planetary System was already known to harbour three planets, including two super-Earths planets which straddle its habitable zone. We report here the detection of an additional planet -- GJ 581e -- with a minimum mass of 1.9 M_earth. With a period of 3.15 days, it is the innermost planet of the System and has a ~5% transit probability. We also correct our previous confusion of the orbital period of GJ 581d (the outermost planet) with a one-year alias, thanks to an extended time span and many more measurements. The revised period is 66.8 days, and locates the semi-major axis inside the habitable zone of the low mass star. The dynamical stability of the 4-planet System imposes an upper bound on the orbital plane inclination. The planets cannot be more massive than approximately 1.6 times their minimum mass.
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misaligned spin orbit in the xo 3 Planetary System
Astronomy and Astrophysics, 2008Co-Authors: G Hebrard, X Bonfils, F Bouchy, C Moutou, F Pont, B Loeillet, M Rabus, I BoisseAbstract:The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. These unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for other transiting planets. We performed radial velocity measurements of XO-3 with the SOPHIE spectrograph at the 1.93 m telescope of Haute-Provence Observatory during a Planetary transit and at other orbital phases. This allowed us to observe the Rossiter-McLaughlin effect and, together with a new analysis of the transit light curve, to refine the parameters of the planet. The unusual shape of the radial velocity anomaly during the transit provides a hint of a nearly transverse Rossiter-McLaughlin effect. The sky-projected angle between the Planetary orbital axis and the stellar rotation axis should be λ = 70 ◦ ± 15 ◦ to be compatible with our observations. This suggests that some close-in planets might result from gravitational interaction between planets and/or stars rather than migration due to interaction with the accretion disk. This surprising result requires confirmation by additional observations, especially at lower airmass, to fully exclude the possibility that the signal is due to Systematic effects.
Michael Meyer - One of the best experts on this subject based on the ideXlab platform.
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thermal infrared mmtao observations of the hr 8799 Planetary System
The Astrophysical Journal, 2010Co-Authors: Philip M Hinz, Timothy J Rodigas, Matthew A Kenworthy, Suresh Sivanandam, Aren Heinze, Eric E Mamajek, Michael MeyerAbstract:We present direct imaging observations at wavelengths of 3.3, 3.8 (L' band), and 4.8 (M band) μm, for the Planetary System surrounding HR 8799. All three planets are detected at L' . The c and d components are detected at 3.3 μm, and upper limits are derived from the M-band observations. These observations provide useful constraints on warm giant planet atmospheres. We discuss the current age constraints on the HR 8799 System and show that several potential co-eval objects can be excluded from being co-moving with the star. Comparison of the photometry is made to models for giant planet atmospheres. Models that include non-equilibrium chemistry provide a reasonable match to the colors of c and d. From the observed colors in the thermal infrared, we estimate T eff < 960 K for b and T eff = 1300 and 1170 K for c and d, respectively. This provides an independent check on the effective temperatures and thus masses of the objects from the Marois et al. results.
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thermal infrared mmtao observations of the hr 8799 Planetary System
arXiv: Earth and Planetary Astrophysics, 2010Co-Authors: Philip M Hinz, Timothy J Rodigas, Matthew A Kenworthy, Suresh Sivanandam, Aren Heinze, Eric E Mamajek, Michael MeyerAbstract:We present direct imaging observations at wavelengths of 3.3, 3.8 (L',band), and 4.8 (M band) microns, for the Planetary System surrounding HR 8799. All three planets are detected at L'. The c and d component are detected at 3.3 microns, and upper limits are derived from the M band observations. These observations provide useful constraints on warm giant planet atmospheres. We discuss the current age constraints on the HR 8799 System, and show that several potential co-eval objects can be excluded from being co-moving with the star. Comparison of the photometry is made to models for giant planet atmospheres. Models which include non-equilibrium chemistry provide a reasonable match to the colors of c and d. From the observed colors in the thermal infrared we estimate T_eff < 960 K for b, and T_eff=1300 and 1170 K for c and d, respectively. This provides an independent check on the effective temperatures and thus masses of the objects from the Marois 2008 results.
G Hebrard - One of the best experts on this subject based on the ideXlab platform.
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the corot 7 Planetary System two orbiting super earths
Astronomy and Astrophysics, 2009Co-Authors: D Queloz, F Bouchy, C Moutou, A P Hatzes, G Hebrard, R Alonso, M Auvergne, A Baglin, M BarbieriAbstract:We report on an intensive observational campaign carried out with HARPS at the 3.6 m telescope at La Silla on the star CoRoT-7. Additional simultaneous photometric measurements carried out with the Euler Swiss telescope have demonstrated that the observed radial velocity variations are dominated by rotational modulation from cool spots on the stellar surface. Several approaches were used to extract the radial velocity signal of the planet(s) from the stellar activity signal. First, a simple pre-whitening procedure was employed to find and subsequently remove periodic signals from the complex frequency structure of the radial velocity data. The dominant frequency in the power spectrum was found at 23 days, which corresponds to the rotation period of CoRoT-7. The 0.8535 day period of CoRoT-7b Planetary candidate was detected with an amplitude of 3.3 m s −1 . Most other frequencies, some with amplitudes larger than the CoRoT-7b signal, are most likely associated with activity. A second approach used harmonic decomposition of the rotational period and up to the first three harmonics to filter out the activity signal from radial velocity variations caused by orbiting planets. After correcting the radial velocity data for activity, two periodic signals are detected: the CoRoT-7b transit period and a second one with a period of 3.69 days and an amplitude of 4 m s −1 . This second signal was also found in the pre-whitening analysis. We attribute the second signal to a second, more remote planet CoRoT-7c . The orbital solution of both planets is compatible with circular orbits. The mass of CoRoT-7b is 4.8 ± 0. 8( M⊕) and that of CoRoT-7c is 8.4 ± 0. 9( M⊕), assuming both planets are on coplanar orbits. We also investigated the false positive scenario of a blend by a faint stellar binary, and this may be rejected by the stability of the bisector on a nightly scale. According to their masses both planets belong to the super-Earth planet category. The average density of CoRoT-7b is ρ = 5.6 ± 1. 3gc m −3 , similar to the Earth. The CoRoT-7 Planetary System provides us with the first insight into the physical nature of short period super-Earth planets recently detected by radial velocity surveys. These planets may be denser than Neptune and therefore likely made of rocks like the Earth, or a mix of water ice and rocks.
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spin orbit misalignment in the hd 80606 Planetary System
Astronomy and Astrophysics, 2009Co-Authors: F Pont, X Bonfils, F Bouchy, C Moutou, G Hebrard, D Ehrenreich, Jonathan Irwin, T Guillot, S Aigrain, Zachory K BertaAbstract:We recently reported the photometric and spectroscopic detection of the primary transit of the 111-day-period, eccentric extra-solar planet HD 80606b, at Observatoire de Haute-Provence, France. The whole egress of the primary transit and a section of its central part were observed, allowing the measurement of the Planetary radius, and evidence for a spin-orbit misalignment through the observation of the Rossiter-McLaughlin anomaly. The ingress not having been observed for this long-duration transit, uncertainties remained in the parameters of the System. We present here a refined, combined analysis of our photometric and spectroscopic data, together with further published radial velocities, ground-based photometry, and Spitzer photometry around the secondary eclipse, as well as new photometric measurements of HD 80606 acquired at Mount Hopkins, Arizona, just before the beginning of the primary transit. Although the transit is not detected in those new data, they provide an upper limit for the transit duration, which narrows down the possible behaviour of the Rossiter-McLaughlin anomaly in the unobserved part of the transit. We analyse the whole data with a Bayesian approach using a Markov-chain Monte Carlo integration on all available information. We find Rp = 0.98 ± 0.03RJup for the Planetary radius, and a total primary transit duration of 11.9 ± 1.3 h from first to fourth contact. Our analysis reinforces the hypothesis of spin-orbit misalignment in this System (alignment excluded at >95% level), with a positive projected angle between the Planetary orbital axis and the stellar rotation (median solution λ ∼ 50 ◦ ). As HD 80606 is a component of a binary System, the peculiar orbit of its planet could result from a Kozai mechanism.
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misaligned spin orbit in the xo 3 Planetary System
Astronomy and Astrophysics, 2008Co-Authors: G Hebrard, X Bonfils, F Bouchy, C Moutou, F Pont, B Loeillet, M Rabus, I BoisseAbstract:The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. These unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for other transiting planets. We performed radial velocity measurements of XO-3 with the SOPHIE spectrograph at the 1.93 m telescope of Haute-Provence Observatory during a Planetary transit and at other orbital phases. This allowed us to observe the Rossiter-McLaughlin effect and, together with a new analysis of the transit light curve, to refine the parameters of the planet. The unusual shape of the radial velocity anomaly during the transit provides a hint of a nearly transverse Rossiter-McLaughlin effect. The sky-projected angle between the Planetary orbital axis and the stellar rotation axis should be λ = 70 ◦ ± 15 ◦ to be compatible with our observations. This suggests that some close-in planets might result from gravitational interaction between planets and/or stars rather than migration due to interaction with the accretion disk. This surprising result requires confirmation by additional observations, especially at lower airmass, to fully exclude the possibility that the signal is due to Systematic effects.
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misaligned spin orbit in the xo 3 Planetary System
arXiv: Astrophysics, 2008Co-Authors: G Hebrard, X Bonfils, F Bouchy, C Moutou, F Pont, B Loeillet, M Rabus, I BoisseAbstract:The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. The unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for other transiting planets. We performed radial velocity measurements of XO-3 with the SOPHIE spectrograph at the 1.93-m telescope of Haute-Provence Observatory during a Planetary transit, and at other orbital phases. This allowed us to observe the Rossiter-McLaughlin effect and, together with a new analysis of the transit light curve, to refine the parameters of the planet. The unusual shape of the radial velocity anomaly during the transit provides a hint for a nearly transverse Rossiter-McLaughlin effect. The sky-projected angle between the Planetary orbital axis and the stellar rotation axis should be lambda = 70 +/- 15 degrees to be compatible with our observations. This suggests that some close-in planets might result from gravitational interaction between planets and/or stars rather than migration due to interaction with the accretion disk. This surprising result requires confirmation by additional observations, especially at lower airmass, to fully exclude the possibility that the signal is due to Systematic effects.
D Queloz - One of the best experts on this subject based on the ideXlab platform.
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the corot 7 Planetary System two orbiting super earths
Astronomy and Astrophysics, 2009Co-Authors: D Queloz, F Bouchy, C Moutou, A P Hatzes, G Hebrard, R Alonso, M Auvergne, A Baglin, M BarbieriAbstract:We report on an intensive observational campaign carried out with HARPS at the 3.6 m telescope at La Silla on the star CoRoT-7. Additional simultaneous photometric measurements carried out with the Euler Swiss telescope have demonstrated that the observed radial velocity variations are dominated by rotational modulation from cool spots on the stellar surface. Several approaches were used to extract the radial velocity signal of the planet(s) from the stellar activity signal. First, a simple pre-whitening procedure was employed to find and subsequently remove periodic signals from the complex frequency structure of the radial velocity data. The dominant frequency in the power spectrum was found at 23 days, which corresponds to the rotation period of CoRoT-7. The 0.8535 day period of CoRoT-7b Planetary candidate was detected with an amplitude of 3.3 m s −1 . Most other frequencies, some with amplitudes larger than the CoRoT-7b signal, are most likely associated with activity. A second approach used harmonic decomposition of the rotational period and up to the first three harmonics to filter out the activity signal from radial velocity variations caused by orbiting planets. After correcting the radial velocity data for activity, two periodic signals are detected: the CoRoT-7b transit period and a second one with a period of 3.69 days and an amplitude of 4 m s −1 . This second signal was also found in the pre-whitening analysis. We attribute the second signal to a second, more remote planet CoRoT-7c . The orbital solution of both planets is compatible with circular orbits. The mass of CoRoT-7b is 4.8 ± 0. 8( M⊕) and that of CoRoT-7c is 8.4 ± 0. 9( M⊕), assuming both planets are on coplanar orbits. We also investigated the false positive scenario of a blend by a faint stellar binary, and this may be rejected by the stability of the bisector on a nightly scale. According to their masses both planets belong to the super-Earth planet category. The average density of CoRoT-7b is ρ = 5.6 ± 1. 3gc m −3 , similar to the Earth. The CoRoT-7 Planetary System provides us with the first insight into the physical nature of short period super-Earth planets recently detected by radial velocity surveys. These planets may be denser than Neptune and therefore likely made of rocks like the Earth, or a mix of water ice and rocks.
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The HARPS search for southern extra-solar planets.XIII. A Planetary System with 3 super-Earths (4.2, 6.9, and 9.2 M-Earth)
Astronomy and Astrophysics - A&A, 2009Co-Authors: M Mayor, S Udry, Jeanloup Bertaux, D Queloz, C. Lovis, F. Pepe, W. Benz, François Bouchy, C. Mordasini, D. SégransanAbstract:We report the detection of a Planetary System with three Super-Earths orbiting HD 40307. HD 40307 is a K2 V metal-deficient star at a distance of only 13 parsec, which is part of the HARPS GTO high-precision planet-search programme. The three planets on circular orbits have very low minimum masses of 4.2, 6.9, and 9.2 Earth masses and periods of 4.3, 9.6, and 20.5 days, respectively. The planet with the shortest period is the lowest mass planet detected to-date orbiting a main sequence star. The detection of the correspondingly low amplitudes of the induced radial-velocity variations is secured completely by the 135 high-quality HARPS observations illustrated by the radial-velocity residuals around the 3-Keplerian solution of only 0.85 ms-1. Activity and bisector indicators exclude any significant perturbations of stellar intrinsic origin, which supports a Planetary interpretation. In contrast to most planet-host stars, HD 40307 has a significantly sub-solar metallicity ([Fe/H] = -0.31), which suggests that very light planets might have a different dependence on host star metallicity than gas giant planets. In addition to the 3 planets close to the central star, a small drift in the radial-velocity residuals implies the presence of another companion in the System, the nature of which is still unknown.
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the harps search for southern extra solar planets xiii a Planetary System with 3 super earths 4 2 6 9 and 9 2 m
Astronomy and Astrophysics, 2009Co-Authors: M Mayo, Christoph Mordasini, S Udry, Jeanloup Ertau, F Ouchy, D Queloz, C. Lovis, F. Pepe, Willy Enz, D SegransaAbstract:Received ; accepted To be inserted later Abstract. This paper reports on the detection of a Planetary System with three Super-Earths orbiting HD 40307. HD 40307 is a K2 V metal-deficient star at a distance of only 13 parsec, part of the HARPS GTO high-precision planet-search programme. The three planets on circular orbits have very low minimum masses of respectively 4.2, 6.9 and 9.2 Earth masses and periods of 4.3, 9.6 and 20.5 days. The planet with the shortest period is the lightest planet detected to-date orbiting a main sequence star. The detection of the correspondingly low amplitudes of the induced radial-velocity variations is completely secured by the 135 very high-quality HARPS observations illustrated by the radial-velocity residuals around the 3-Keplerian solution of only 0.85 ms 1 . Activity and bisector indicators exclude any significant perturbations of stellar intrinsic origin, which supports the Planetary interpretation. Contrary to most planet-host stars, HD 40307 has a marked sub-solar metallicity ((Fe/H) = 0.31), further supporting the already raised possibility that the occurrence of very light planets might show a di erent dependence on host star's metallicity compared to the population of gas giant planets. In addition to the 3 planets close to the central star, a small drift of the radial-velocity residuals reveals the presence of another companion in the System the nature of which is still unknown.
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an extrasolar Planetary System with three neptune mass planets
Nature, 2006Co-Authors: Christophe Lovis, Jacques Laskar, Yann Alibert, Christoph Mordasini, M Mayor, F Bouchy, F. Pepe, W. Benz, A.c.m. Correia, D QuelozAbstract:Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called ‘hot Neptunes’ or ‘super-Earths’ around Sun-like stars. These planets have masses 5–20 times larger than the Earth and are mainly found on close-in orbits with periods of 2–15 days. Here we report a System of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun–Earth distance). Simulations show that the System is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star. As the techniques used to search for extrasolar planets have been refined, more and more have been discovered (over 170), and they get smaller. In recent years seven ‘hot Neptunes’ or ‘super-Earths’ have been detected. These have masses 5–20 times larger than the Earth and are in close-in orbits (periods of 2–15 days) around Sun-like stars. Now the first multiple System of three Neptune-mass planets has been found, with periods of 8.67, 31.6 and (in the ‘habitable’ zone) 197 days. They are orbiting the nearby star HD 69830. Theoretical calculations favour a mainly rocky composition for both inner planets. The outer planet probably has a significant gaseous envelope surrounding a rocky/icy core: it is the first Neptune-mass object detected inside the habitable zone of a Sun-like star. Simulations show that the System of three Neptune-mass planets is in a dynamically stable configuration, with theoretical calculations favouring a mainly rocky composition for both inner planets, but a significant gaseous envelope surrounding a rocky/icy core for the outer planet.
