The SOPHIE search for northern extrasolar planets

Courcol, B.; Bouchy, F.; Pepe, F.; Santerne, A.; Delfosse, X.; Arnold, L.; Astudillo-Defru, N.; Boisse, I.; Bonfils, X.; Borgniet, S.; Bourrier, V.; Cabrera, Nicole; Deleuil, M.; Demangeon, O.; Díaz, R. F.; Ehrenreich, D.; Forveille, T.; Hébrard, G.; Lagrange, A. M.; Montagnier, G.; Moutou, C.; Rey, J.; Santos, N. C.; Ségransan, D.; Udry, S.; Wilson, Paul

doi:10.1051/0004-6361/201526329

Cited by 71 publications

(77 citation statements)

References 31 publications

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“…Courcol et al 2015;Díaz et al 2016a;Hébrard et al 2016). Some of the SOPHIE targets were first observed within the ELODIE historical programme initiated by M. Mayor and D. Queloz in 1994, this extends our baseline to over 22 years and allows a long-term characterization of the orbits.…”

Section: Introductionmentioning

confidence: 67%

The SOPHIE search for northern extrasolar planets

Rey

Hébrard

Bouchy

et al. 2017

A&A

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We present new radial velocity measurements for three low-metallicity solar-like stars observed with the SOPHIE spectrograph and its predecessor ELODIE, both installed at the 193 cm telescope of the Haute-Provence Observatory, allowing the detection and characterization of three new giant extrasolar planets in intermediate periods of 1.7 to 3.7 years. All three stars, HD17674, HD42012 and HD29021 present single giant planetary companions with minimum masses between 0.9 and 2.5 M Jup . The range of periods and masses of these companions, along with the distance of their host stars, make them good targets to look for astrometric signals over the lifetime of the new astrometry satellite Gaia. We discuss the preliminary astrometric solutions obtained from the first Gaia data release.

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Section: Introductionmentioning

confidence: 67%

The SOPHIE search for northern extrasolar planets

Rey

Hébrard

Bouchy

et al. 2017

A&A

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“…Note that TESS (Ricker et al 2015) and PLATO (Rauer et al 2014) will be observing much brighter stars than the Kepler targets. We will therefore have access to better RV precision with the SOPHIE spectrograph, allowing us to do similar work on the populations of smaller planets, down to hot super-Earths and warm Neptunes (Courcol et al 2015).…”

Section: Discussionmentioning

confidence: 99%

“…These spectroscopic diagnostics are used to reveal the presence of contaminating stars, therefore likely false positives that might be the source of the transit event (Santos et al 2002;Torres et al 2005). Several stars that present a ∼100 m s −1 scatter in FWHM, including the RV constant star HD 185144 , we concluded this scatter was from the insufficient thermal control of the instrument that introduces slight changes in focus (Courcol et al 2015). For this reason, we used the FWHM as a vetting tool only if the variation is much larger than 100 m s −1 .…”

Section: Sophie Observations and Reductionmentioning

confidence: 95%

SOPHIE velocimetry ofKeplertransit candidates

Santerne

Moutou

Tsantaki

et al. 2016

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While giant extrasolar planets have been studied for more than two decades now, there are still some open questions as to their dominant formation and migration processes, as well as to their atmospheric evolution in different stellar environments. In this paper, we study a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days. We first defined a sample of 129 giant-planet candidates that we followed up with the SOPHIE spectrograph (OHP, France) in a 6-year radial velocity campaign. This allowed us to unveil the nature of these candidates and to measure a false-positive rate of 54.6 ± 6.5% for giant-planet candidates orbiting within 400 days of period. Based on a sample of confirmed or likely planets, we then derived the occurrence rates of giant planets in different ranges of orbital periods. The overall occurrence rate of giant planets within 400 days is 4.6 ± 0.6%. We recovered, for the first time in the Kepler data, the different populations of giant planets reported by radial velocity surveys. Comparing these rates with other yields, we find that the occurrence rate of giant planets is lower only for hot Jupiters but not for the longer-period planets. We also derive a first measurement of the occurrence rate of brown dwarfs in the brown-dwarf desert with a value of 0.29 ± 0.17%. Finally, we discuss the physical properties of the giant planets in our sample. We confirm that giant planets receiving moderate irradiation are not inflated, but we find that they are on average smaller than predicted by formation and evolution models. In this regime of low-irradiated giant planets, we find a possible correlation between their bulk density and the iron abundance of the host star, which needs more detections to be confirmed.

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“…Spectra taken after June 2011 are corrected using a set of standard stars that are monitored every night. This correction accounts for any instrumental variations and is described in detail in Courcol et al (2015).…”

Section: Observations and Datamentioning

confidence: 99%

An extreme planetary system around HD 219828

Santos

Santerne

Faria

et al. 2016

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Context. With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. This wide diversity provides fundamental clues to the processes of planet formation and evolution. Aims. We present a full investigation of the HD 219828 system, a bright metal-rich star for which a hot Neptune has previously been detected. Methods. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD 219828. The spectra were used to characterise the star and its chemical abundances, as well as to check for spurious, activity induced signals. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. Results. We announce the discovery of a long period (P = 13.1 yr) massive (m sin i = 15.1 M Jup ) companion (HD 219828 c) in a very eccentric orbit (e = 0.81). The same data confirms the existence of a hot Neptune, HD 219828 b, with a minimum mass of 21 M ⊕ and a period of 3.83 days. The dynamical analysis shows that the system is stable, and that the equilibrium eccentricity of planet b is close to zero. Conclusions. The HD 219828 system is extreme and unique in several aspects. First, ammong all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like HD 219828, with a hot Neptune and a long-period massive companion are more frequent than similar systems with a hot Jupiter instead. This suggests that the formation of hot Neptunes follows a different path than the formation of their hot jovian counterparts. The high mass, long period, and eccentricity of HD 219828 c also make it a good target for Gaia astrometry as well as a potential target for atmospheric characterisation, using direct imaging or high-resolution spectroscopy. Astrometric observations will allow us to derive its real mass and orbital configuration. If a transit of HD 219828 b is detected, we will be able to fully characterise the system, including the relative orbital inclinations. With a clearly known mass, HD 219828 c may become a benchmark object for the range in between giant planets and brown dwarfs.

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The SOPHIE search for northern extrasolar planets

Cited by 71 publications

References 31 publications

The SOPHIE search for northern extrasolar planets

The SOPHIE search for northern extrasolar planets

SOPHIE velocimetry ofKeplertransit candidates

An extreme planetary system around HD 219828

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