Research Outputs

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    Publication
    The SOPHIE search for northern extrasolar planets. XVII. A wealth of new objects: Six cool Jupiters, three brown dwarfs, and 16 low-mass binary stars
    (EDP Sciences, 2021) ;
    Dalal, S.
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    Kiefer, F.
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    Hébrard, G.
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    Sahlmann, J.
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    Sousa, S.
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    Forveille, T.
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    Delfosse, X.
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    Arnold, L.
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    Bonfils, X.
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    Boisse, I.
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    Bouchy, F.
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    Bourrier, V.
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    Brugger, B.
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    Cortés-Zuleta, P.
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    Deleuil, M.
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    Demangeon, O.
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    Díaz, R.
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    Hara, N.
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    Heidari, N.
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    Hobson, J.
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    Lopez, T.
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    Lovis, C.
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    Martioli, E.
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    Mignon, L.
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    Mousis, O.
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    Moutou, C.
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    Rey, J.
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    Santerne, A.
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    Santos, N.
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    Ségransan, D.
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    Strøm, P.
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    Udry, S.
    Distinguishing classes within substellar objects and understanding their formation and evolution need larger samples of substellar companions such as exoplanets, brown dwarfs, and low-mass stars. In this paper, we look for substellar companions using radial velocity surveys of FGK stars with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We assign here the radial velocity variations of 27 stars to their orbital motion induced by low-mass companions. We also constrained their plane-of-the-sky motion using HIPPARCOS and Gaia Data Release 1 measurements, which constrain the true masses of some of these companions. We report the detection and characterization of six cool Jupiters, three brown dwarf candidates, and 16 low-mass stellar companions. We additionally update the orbital parameters of the low-mass star HD 8291 B, and we conclude that the radial velocity variations of HD 204277 are likely due to stellar activity despite resembling the signal of a giant planet. One of the new giant planets, BD+631405 b, adds to the population of highly eccentric cool Jupiters, and it is presently the most massive member. Two of the cool Jupiter systems also exhibit signatures of an additional outer companion. The orbital periods of the new companions span 30 days to 11.5 yr, their masses 0.72 MJ–0.61 M, and their eccentricities 0.04–0.88. These discoveries probe the diversity of substellar objects and low-mass stars, which will help constrain the models of their formation and evolution.
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    Publication
    TOI-4860 b, a short-period giant planet transiting an M3.5 dwarf
    (EDP ​​​​Sciences, 2024) ;
    Almenara, J.
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    Bonfils, X.
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    Bryant, E.
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    Jordán, A.
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    Hébrard, G.
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    Martioli, E.
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    Correia, A.
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    Cadieux, C.
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    Arnold, L.
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    Artigau, É.
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    Bakos, G.
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    Barros, S.
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    Bayliss, D.
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    Bouchy, F.
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    Boué, G.
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    Brahm, R.
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    Carmona, A.
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    Charbonneau, D.
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    Ciardi, D.
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    Cloutier, R.
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    Cointepas, M.
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    Cook, N.
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    Cowan, N.
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    Delfosse, X.
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    Dias do Nascimento, J.
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    Donati, J.
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    Doyon, R.
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    Forveille, T.
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    Fouqué, P.
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    Gaidos, E.
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    Gilbert, E.
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    da Silva, J.
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    Hartman, J.
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    Hesse, K.
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    Hobson, M.
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    Jenkins, J.
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    Kiefer, F.
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    Kostov, V.
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    Laskar, J.
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    Lendl, M.
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    L’Heureux, A.
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    Martins, J.
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    Menou, K.
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    Moutou, C.
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    Murgas, F.
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    Polanski, A. S.
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    Rapetti, D.
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    Sedaghati, E.
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    Shang, H.
    We report the discovery and characterisation of a giant transiting planet orbiting a nearby M3.5V dwarf (d = 80.4pc, G = 15.1 mag, K=11.2mag, R* = 0.358 ± 0.015 R⊙, M* = 0.340 ± 0.009 M⊙). Using the photometric time series from TESS sectors 10, 36, 46, and 63 and near-infrared spectrophotometry from ExTrA, we measured a planetary radius of 0.77 ± 0.03 RJ and an orbital period of 1.52 days. With high-resolution spectroscopy taken by the CFHT/SPIRou and ESO/ESPRESSO spectrographs, we refined the host star parameters ([Fe/H] = 0.27 ± 0.12) and measured the mass of the planet (0.273 ± 0.006 MJ). Based on these measurements, TOI-4860 b joins the small set of massive planets (>80 ME) found around mid to late M dwarfs (<0.4 R⊙), providing both an interesting challenge to planet formation theory and a favourable target for further atmospheric studies with transmission spectroscopy. We identified an additional signal in the radial velocity data that we attribute to an eccentric planet candidate (e = 0.66 ± 0.09) with an orbital period of 427 ± 7 days and a minimum mass of 1.66 ± 0.26 MJ, but additional data would be needed to confirm this.