Browsing by Author "Korth, Judith"

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    K2-280 b - a low density warm sub-Saturn around a mildly evolved star
    (2020) Nowak, Grzegorz; Palle, Enric; Gandolfi, Davide; Deeg, Hans J.; Hirano, Teruyuki; Barragan, Oscar; Kuzuhara, Masayuki; Dai, Fei; Luque, Rafael; Persson, Carina M.; Fridlund, Malcolm; Johnson, Marshall C.; Korth, Judith; Livingston, John H.; Grziwa, Sascha; Mathur, Savita; Hatzes, Artie P.; Prieto-Arranz, Jorge; Nespral, David; Hidalgo, Diego; Hjorth, Maria; Albrecht, Simon; Van Eylen, Vincent; Lam, Kristine W. F.; Cochran, William D.; Esposito, Massimiliano; Csizmadia, Szilard; Guenther, Eike W.; Kabath, Petr; Blay, Pere; Brahm, Rafael; Jordan, Andres; Espinoza, Nestor; Rojas, Felipe; Casasayas Barris, Nuria; Rodler, Florian; Alonso Sobrino, Roi; Cabrera, Juan; Carleo, Ilaria; Chaushev, Alexander; de Leon, Jerome; Eigmueller, Philipp; Endl, Michael; Erikson, Anders; Fukui, Akihiko; Georgieva, Iskra; Gonzalez-Cuesta, Lucia; Knudstrup, Emil; Lund, Mikkel N.; Montanes Rodriguez, Pilar; Murgas, Felipe; Narita, Norio; Niraula, Prajwal; Paetzold, Martin; Rauer, Heike; Redfield, Seth; Ribas, Ignasi; Skarka, Marek; Smith, Alexis M. S.; Subjak, Jano
    We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = 0.35(-0.04)(+0.05)) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has a radius of R-b = 7.50 +/- 0.44 R-circle plus and a mass of M-b = 37.1 +/- 5.6 M-circle plus, yielding a mean density of rho(b) = 0.48(-0.10)(+0.13) g cm(-3). The host star is a mildly evolved G7 star with an effective temperature of T-eff = 5500 +/- 100 K, a surface gravity of log g(star) = 4.21 +/- 0.05 (cgs), and an iron abundance of [Fe/H] = 0.33 +/- 0.08 dex, and with an inferred mass of M-star = 1.03 +/- 0.03 M-circle dot and a radius of R-star = 1.28 +/- 0.07 R-circle dot. We discuss the importance of K2-280 b for testing formation scenarios of sub-Saturn planets and the current sample of this intriguing group of planets that are absent in the Solar system.
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    Mass determination of two Jupiter-sized planets orbiting slightly evolved stars: TOI-2420 b and TOI-2485 b
    (2024) Carleo, Ilaria; Barragan, Oscar; Persson, Carina M.; Fridlund, Malcolm; Lam, Kristine W. F.; Messina, Sergio; Gandolfi, Davide; Smith, Alexis M. S.; Johnson, Marshall C.; Cochran, William; Osborne, Hannah L. M.; Brahm, Rafael; Ciardi, David R.; Collins, Karen A.; Everett, Mark E.; Giacalone, Steven; Guenther, Eike W.; Hatzes, Artie; Hellier, Coel; Horner, Jonathan; Kabath, Petr; Korth, Judith; MacQueen, Phillip; Masseron, Thomas; Murgas, Felipe; Nowak, Grzegorz; Rodriguez, Joseph E.; Watkins, Cristilyn N.; Wittenmyer, Rob; Zhou, George; Ziegler, Carl; Bieryla, Allyson; Boyd, Patricia T.; Clark, Catherine A.; Dressing, Courtney D.; Eastman, Jason D.; Eberhardt, Jan; Endl, Michael; Espinoza, Nestor; Fausnaugh, Michael; Guerrero, Natalia M.; Henning, Thomas; Hesse, Katharine; Hobson, Melissa J.; Howell, Steve B.; Jordan, Andres; Latham, David W.; Lund, Michael B.; Mireles, Ismael; Narita, Norio; Tala Pinto, Marcelo; Pugh, Teznie; Quinn, Samuel N.; Ricker, George; Rodriguez, David R.; Rojas, Felipe I.; Rose, Mark E.; Rudat, Alexander; Sarkis, Paula; Savel, Arjun B.; Schlecker, Martin; Schwarz, Richard P.; Seager, Sara; Shporer, Avi; Smith, Jeffrey C.; Stassun, Keivan G.; Stockdale, Chris; Trifonov, Trifon; Vanderspek, Roland; Winn, Joshua N.; Wright, Duncan
    Context. Hot and warm Jupiters might have undergone the same formation and evolution path, but the two populations exhibit different distributions of orbital parameters. This challenges our understanding of their actual origin. Aims. We report the results of our warm Jupiters survey, which was carried out with the CHIRON spectrograph within the KESPRINT collaboration. We addressed the question of the population origin by studying two planets that might help to bridge the gap between the two populations. Methods. We confirm two planets and determine their mass. One is a hot Jupiter (with an orbital period shorter than 10 days), TOI-2420 b, and the other is a warm Jupiter, TOI-2485 b. We analyzed them using a wide variety of spectral and photometric data in order to characterize these planetary systems. Results. We found that TOI-2420 b has an orbital period of P-b=5.8 days, a mass of M-b=0.9 M-J, and a radius of R-b=1.3 R-J, with a planetary density of 0.477 g cm(-3). TOI-2485 b has an orbital period of P-b=11.2 days, a mass of M-b=2.4 M-J, and a radius of R-b=1.1 R-J with a density of 2.36 g cm(-3). Conclusions. With the current parameters, the migration history for TOI-2420 b and TOI-2485 b is unclear: Scenarios of a high-eccentricity migration cannot be ruled out, and the characteristics of TOI-2485 b even support this scenario.
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    Precise Transit and Radial-velocity Characterization of a Resonant Pair: The Warm Jupiter TOI-216c and Eccentric Warm Neptune TOI-216b
    (2021) Dawson, Rebekah I.; Huang, Chelsea X.; Brahm, Rafael; Collins, Karen A.; Hobson, Melissa J.; Jordan, Andres; Dong, Jiayin; Korth, Judith; Trifonov, Trifon; Abe, Lyu; Agabi, Abdelkrim; Bruni, Ivan; Butler, R. Paul; Barbieri, Mauro; Collins, Kevin I.; Conti, Dennis M.; Crane, Jeffrey D.; Crouzet, Nicolas; Dransfield, Georgina; Evans, Phil; Espinoza, Nestor; Gan, Tianjun; Guillot, Tristan; Henning, Thomas; Lissauer, Jack J.; Jensen, Eric L. N.; Sainte, Wenceslas Marie; Mekarnia, Djamel; Myers, Gordon; Nandakumar, Sangeetha; Relles, Howard M.; Sarkis, Paula; Torres, Pascal; Shectman, Stephen; Schmider, Francois-Xavier; Shporer, Avi; Stockdale, Chris; Teske, Johanna; Triaud, Amaury H. M. J.; Wang, Sharon Xuesong; Ziegler, Carl; Ricker, G.; Vanderspek, R.; Latham, David W.; Seager, S.; Winn, J.; Jenkins, Jon M.; Bouma, L. G.; Burt, Jennifer A.; Charbonneau, David; Levine, Alan M.; McDermott, Scott; McLean, Brian; Rose, Mark E.; Vanderburg, Andrew; Wohler, Bill
    TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations (TTVs). Precise characterization of the planets' masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV baseline from TESS and an ongoing ground-based transit observing campaign increase the precision of the mass and eccentricity measurements. We determine that TOI-216c is a warm Jupiter, TOI-216b is an eccentric warm Neptune, and that they librate in 2:1 resonance with a moderate libration amplitude of deg, a small but significant free eccentricity of for TOI-216b, and a small but significant mutual inclination of 12-39 (95% confidence interval). The libration amplitude, free eccentricity, and mutual inclination imply a disturbance of TOI-216b before or after resonance capture, perhaps by an undetected third planet.
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    TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
    (2023) Hobson, Melissa J.; Trifonov, Trifon; Henning, Thomas; Jordan, Andres; Rojas, Felipe; Espinoza, Nestor; Brahm, Rafael; Eberhardt, Jan; Jones, Matias I.; Mekarnia, Djamel; Kossakowski, Diana; Schlecker, Martin; Pinto, Marcelo Tala; Torres Miranda, Pascal Jose; Abe, Lyu; Barkaoui, Khalid; Bendjoya, Philippe; Bouchy, Francois; Buttu, Marco; Carleo, Ilaria; Collins, Karen A.; Colon, Knicole D.; Crouzet, Nicolas; Dragomir, Diana; Dransfield, Georgina; Gasparetto, Thomas; Goeke, Robert F.; Guillot, Tristan; Guenther, Maximilian N.; Howard, Saburo; Jenkins, Jon M.; Korth, Judith; Latham, David W.; Lendl, Monika; Lissauer, Jack J.; Mann, Christopher R.; Mireles, Ismael; Ricker, George R.; Saesen, Sophie; Schwarz, Richard P.; Seager, S.; Sefako, Ramotholo; Shporer, Avi; Stockdale, Chris; Suarez, Olga; Tan, Thiam-Guan; J. Triaud, Amaury H. M.; Ulmer-Moll, Solene; Vanderspek, Roland; Winn, Joshua N.; Wohler, Bill; Zhou, George
    We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5 hr long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199 b has a 104.854-0.002+0.001day period, a mass of 0.17 +/- 0.02 M J, and a radius of 0.810 +/- 0.005 R J. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations (TTVs), pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the nontransiting companion TOI-199 c, which has a period of 273.69-0.22+0.26days and an estimated mass of 0.28-0.01+0.02MJ . This period places it within the conservative habitable zone.