Browsing by Author "Diaz, R. F."

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    HD 207897 b: A dense sub-Neptune transiting a nearby and bright K-type star
    (2022) Heidari, N.; Boisse, I; Orell-Miquel, J.; Hebrard, G.; Acuna, L.; Hara, N. C.; Lillo-Box, J.; Eastman, J. D.; Arnold, L.; Astudillo-Defru, N.; Adibekyan, V; Bieryla, A.; Bonfils, X.; Bouchy, F.; Barclay, T.; Brasseur, C. E.; Borgniet, S.; Bourrier, V; Buchhave, L.; Behmard, A.; Beard, C.; Batalha, N. M.; Courcol, B.; Cortes-Zuleta, P.; Collins, K.; Carmona, A.; Crossfield, I. J. M.; Chontos, A.; Delfosse, X.; Dalal, S.; Deleuil, M.; Demangeon, O. D. S.; Diaz, R. F.; Dumusque, X.; Daylan, T.; Dragomir, D.; Mena, E. Delgado; Dressing, C.; Dai, F.; Dalba, P. A.; Ehrenreich, D.; Forveille, T.; Fulton, B.; Fetherolf, T.; Gaisne, G.; Giacalone, S.; Riazi, N.; Hoyer, S.; Hobson, M. J.; Howard, A. W.; Huber, D.; Hill, M. L.; Hirsch, L. A.; Isaacson, H.; Jenkins, J.; Kane, S. R.; Kiefer, F.; Luque, R.; Latham, D. W.; Lubin, J.; Lopez, T.; Mousis, O.; Moutou, C.; Montagnier, G.; Mignon, L.; Mayo, A.; Mocnik, T.; Murphy, J. M. A.; Palle, E.; Pepe, F.; Petigura, E. A.; Rey, J.; Ricker, G.; Robertson, P.; Roy, A.; Rubenzahl, R. A.; Rosenthal, L. J.; Santerne, A.; Santos, N. C.; Sousa, S. G.; Stassun, K. G.; Stalport, M.; Scarsdale, N.; Strom, P. A.; Seager, S.; Segransan, D.; Tenenbaum, P.; Tronsgaard, R.; Udry, S.; Vanderspek, R.; Vakili, F.; Winn, J.; Weiss, L. M.
    We present the discovery and characterization of a transiting sub-Neptune that orbits the nearby (28 pc) and bright (V = 8.37) K0V star HD 207897 (TOI-1611) with a 16.20-day period. This discovery is based on photometric measurements from the Transiting Exoplanet Survey Satellite mission and radial velocity (RV) observations from the SOPHIE, Automated Planet Finder, and HIRES high-precision spectrographs. We used EXOFASTv2 to model the parameters of the planet and its host star simultaneously, combining photometric and RV data to determine the planetary system parameters. We show that the planet has a radius of 2.50 +/- 0.08 R-E and a mass of either 14.4 +/- 1.6 M-E or 15.9 +/- 1.6 M-E with nearly equal probability. The two solutions correspond to two possibilities for the stellar activity period. The density accordingly is either 5.1 +/- 0.7 g cm(-3) or 5.5(-0.7)(+0.8) g cm(-3), making it one of the relatively rare dense sub-Neptunes. The existence of this dense planet at only 0.12 AU from its host star is unusual in the currently observed sub-Neptune (2 < R-E < 4) population. The most likely scenario is that this planet has migrated to its current position.
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    Millimagnitude photometry for transiting extrasolar planetary candidates V. Follow-up of 30 OGLE transits. New candidates
    (EDP SCIENCES S A, 2010) Pietrukowicz, P.; Minniti, D.; Diaz, R. F.; Fernandez, J. M.; Zoccali, M.; Gieren, W.; Pietrzynski, G.; Ruiz, M. T.; Udalski, A.; Szeifert, T.; Hempel, M.
    Aims. We used VLT/VIMOS images in the V band to obtain light curves of the extrasolar planetary transits OGLE-TR-111 and OGLE-TR-113 and the candidate planetary transits: OGLE-TR-82, OGLE-TR-86, OGLE-TR-91, OGLE-TR-106, OGLE-TR-109, OGLE-TR-110, OGLE-TR-159, OGLE-TR-167, OGLE-TR-170, OGLE-TR-171.
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    OGLE-TR-211 -: a new transiting inflated hot Jupiter from the OGLE survey and ESO LP666 spectroscopic follow-up program
    (2008) Udalski, A.; Pont, F.; Naef, D.; Melo, C.; Bouchy, F.; Santos, N. C.; Moutou, C.; Diaz, R. F.; Gieren, W.; Gillon, M.; Hoyer, S.; Mayor, M.; Mazeh, T.; Minniti, D.; Pietrzynski, G.; Queloz, D.; Ramirez, S.; Ruiz, M. T.; Shporer, A.; Tamuz, O.; Udry, S.; Zoccali, M.; Kubiak, M.; Szymanski, M. K.; Soszynski, I.; Szewczyk, O.; Ulaczyk, K.; Wyrzykowski, L.
    We present results of the photometric campaign for planetary and low-luminosity object transits conducted by the OGLE survey in the 2005 season (Campaign #5). About twenty of the most promising candidates discovered in these data were subsequently verified spectroscopically with the VLT/FLAMES spectrograph.
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    Quantifying the Bayesian Evidence for a Planet in Radial Velocity Data
    (2020) Nelson, B. E.; Ford, E. B.; Buchner, J.; Cloutier, R.; Diaz, R. F.; Faria, J. P.; Hara, N. C.; Rajpaul, V. M.; Rukdee, Surangkhana
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    The SOPHIE search for northern extrasolar planets XVIII. Six new cold Jupiters, including one of the most eccentric exoplanet orbits
    (2021) Demangeon, O. D. S.; Dalal, S.; Hebrard, G.; Nsamba, B.; Kiefer, F.; Camacho, J. D.; Sahlmann, J.; Arnold, L.; Astudillo-Defru, N.; Bonfils, X.; Boisse, I; Bouchy, F.; Bourrier, V; Campante, T.; Delfosse, X.; Deleuil, M.; Diaz, R. F.; Faria, J.; Forveille, T.; Hara, N.; Heidari, N.; Hobson, M. J.; Lopez, T.; Moutou, C.; Rey, J.; Santerne, A.; Sousa, S.; Santos, N. C.; Strom, P. A.; Tsantaki, M.; Udry, S.
    Context. Due to their low transit probability, the long-period planets are, as a population, only partially probed by transit surveys. Radial velocity surveys thus have a key role to play, in particular for giant planets. Cold Jupiters induce a typical radial velocity semi-amplitude of 10 m s(-1), which is well within the reach of multiple instruments that have now been in operation for more than a decade.
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    The SOPHIE search for northern extrasolar planets: XVI. HD 158259: A compact planetary system in a near-3:2 mean motion resonance chain
    (2020) Hara, N. C.; Bouchy, F.; Stalport, M.; Boisse, I; Rodrigues, J.; Delisle, J-B; Santerne, A.; Henry, G. W.; Arnold, L.; Astudillo-Defru, N.; Borgniet, S.; Bonfils, X.; Bourrier, V; Brugger, B.; Courcol, B.; Dalal, S.; Deleuil, M.; Delfosse, X.; Demangeon, O.; Diaz, R. F.; Dumusque, X.; Forveille, T.; Hebrard, G.; Hobson, M.; Kiefer, F.; Lopez, T.; Mignon, L.; Mousis, O.; Moutou, C.; Pepe, F.; Rey, J.; Santos, N. C.; Segransan, D.; Udry, S.; Wilson, P. A.
    Aims. Since 2011, the SOPHIE spectrograph has been used to search for Neptunes and super-Earths in the northern hemisphere. As part of this observational program, 290 radial velocity measurements of the 6.4 V magnitude star HD 158259 were obtained. Additionally, TESS photometric measurements of this target are available. We present an analysis of the SOPHIE data and compare our results with the output of the TESS pipeline.Methods. The radial velocity data, ancillary spectroscopic indices, and ground-based photometric measurements were analyzed with classical and l(1) periodograms. The stellar activity was modeled as a correlated Gaussian noise and its impact on the planet detection was measured with a new technique.Results. The SOPHIE data support the detection of five planets, each with m sin i approximate to 6 M-circle plus, orbiting HD 158259 in 3.4, 5.2, 7.9, 12, and 17.4 days. Though a planetary origin is strongly favored, the 17.4 d signal is classified as a planet candidate due to a slightly lower statistical significance and to its proximity to the expected stellar rotation period. The data also present low frequency variations, most likely originating from a magnetic cycle and instrument systematics. Furthermore, the TESS pipeline reports a significant signal at 2.17 days corresponding to a planet of radius approximate to 1.2 R-circle plus. A compatible signal is seen in the radial velocities, which confirms the detection of an additional planet and yields a approximate to 2 M-circle plus mass estimate.Conclusions. We find a system of five planets and a strong candidate near a 3:2 mean motion resonance chain orbiting HD 158259. The planets are found to be outside of the two and three body resonances.