Browsing by Author "Ricker, George R."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M-dwarf System at 6.9 pc(The American Astronomical Society, 2019-09-23) Winters, Jennifer G.; Medina, Amber A.; Irwin, Jonathan M.; Charbonneau, David; Astudillo-Defru, Nicola; Horch, Elliott P.; Eastman, Jason D.; Vrijmoet, Eliot Halley; Henry, Todd J.; Diamond-Lowe, Hannah; Winston, Elaine; Barclay, Thomas; Bonfils, Xavier; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Udry, Stéphane; Twicken, Joseph D.; Teske, Johanna K.; Tenenbaum, Peter; Pepe, Francesco; Murgas, Felipe; Muirhead, Philip S.; Mink, Jessica; Lovis, Christophe; Levine, Alan M.; Lépine, Sébastien; Jao, Wei-Chun; Henze, Christopher E.; Furész, Gábor; Forveille, Thierry; Figueira, Pedro; Esquerdo, Gilbert A.; Dressing, Courtney D.; Díaz, Rodrigo F.; Delfosse, Xavier; Burke, Christopher J.; Bouchy, François; Berlind, Perry; Almenara, Jose-ManuelWe present the discovery from Transiting Exoplanet Survey Satellite (TESS) data of LTT 1445Ab. At a distance of 6.9 pc, it is the second nearest transiting exoplanet system found to date, and the closest one known for which the primary is an M dwarf. The host stellar system consists of three mid-to-late M dwarfs in a hierarchical configuration, which are blended in one TESS pixel. We use MEarth data and results from the Science Processing Operations Center data validation report to determine that the planet transits the primary star in the system. The planet has a radius of ${1.38}_{-0.12}^{+0.13}$ ${R}_{\oplus }$, an orbital period of ${5.35882}_{-0.00031}^{+0.00030}$ days, and an equilibrium temperature of ${433}_{-27}^{+28}$ K. With radial velocities from the High Accuracy Radial Velocity Planet Searcher, we place a 3σ upper mass limit of 8.4 ${M}_{\oplus }$ on the planet. LTT 1445Ab provides one of the best opportunities to date for the spectroscopic study of the atmosphere of a terrestrial world. We also present a detailed characterization of the host stellar system. We use high-resolution spectroscopy and imaging to rule out the presence of any other close stellar or brown dwarf companions. Nineteen years of photometric monitoring of A and BC indicate a moderate amount of variability, in agreement with that observed in the TESS light-curve data. We derive a preliminary astrometric orbit for the BC pair that reveals an edge-on and eccentric configuration. The presence of a transiting planet in this system hints that the entire system may be co-planar, implying that the system may have formed from the early fragmentation of an individual protostellar core.Item TOI-2525 b and c: A Pair of Massive Warm Giant Planets with Strong Transit Timing Variations Revealed by TESS(AAS, 2023-03-28) Trifonov, Trifon; Brahm, Rafael; Jordán, Andrés; Hartogh, Christian; Henning, Thomas; Hobson, Melissa J.; Schlecker, Martin; Howard, Saburo; Reichardt, Finja; Espinoza, Nestor; Lee, Man Hoi; Nesvorny, David; Rojas, Felipe I.; Barkaoui, Khalid; Kossakowski, Diana; Boyle, Gavin; Dreizler, Stefan; Kürster, Martin; Heller, René; Guillot, Tristan; Triaud, Amaury H. M. J.; Abe, Lyu; Agabi, Abdelkrim; Bendjoya, Philippe; Crouzet, Nicolas; Dransfield, Georgina; Gasparetto, Thomas; Günther, Maximilian N.; Marie-Sainte, Wenceslas; Mékarnia, Djamel; Suarez, Olga; Teske, Johanna; Butler, R. Paul; Crane, Jeffrey D.; Shectman, Stephen; Ricker, George R.; Shporer, Avi; Vanderspek, Roland; Jenkins, Jon M.; Wohler, Bill; Collins, Karen A.; Collins, Kevin I.; Ciardi, David R.; Barclay, Thomas; Mireles, Ismael; Seager, Sara; Winn, Joshua N.The K-type star TOI-2525 has an estimated mass of M = 0.849⁺⁰.⁰²⁴ ₋₀.₀₃₃ M⊙ and radius of R = 0.785⁺⁰.⁰⁰⁷ ₋₀.₀₀₇ R⊙ observed by the TESS mission in 22 sectors (within sectors 1 and 39). The TESS light curves yield significant transit events of two companions, which show strong transit timing variations (TTVs) with a semiamplitude of ?6 hr. We performed TTV dynamical and photodynamical light-curve analysis of the TESS data combined with radial velocity measurements from FEROS and PFS, and we confirmed the planetary nature of these companions. The TOI-2525 system consists of a transiting pair of planets comparable to Neptune and Jupiter with estimated dynamical masses of m₆ = 0.088⁺⁰.⁰⁰⁵₋₀.₀₀₄ and m꜀ = 0.709⁺⁰.⁰³⁴₋₀.₀₃₃ Mⱼᵤₚ, radii of r₆ = 0.88⁺⁰.⁰²₋₀.₀₂ and r꜀ = 0.98⁺⁰.⁰²₋₀.₀₂ Rⱼᵤₚ, and orbital periods of P₆ = 23.288⁺⁰.⁰⁰¹₋₀.₀₀₂ and P꜀ = 49.260⁺⁰.⁰⁰¹₋₀.₀₀₁ days for the inner and outer planet, respectively. The period ratio is close to the 2:1 period commensurability, but the dynamical simulations of the system suggest that it is outside the mean-motion resonance (MMR) dynamical configuration. Object TOI-2525 b is among the lowest-density Neptune-mass planets known to date, with an estimated median density of P₆ = 0.174⁺⁰.⁰¹⁶₋₀.₀₁₅ g cm⁻³. The TOI-2525 system is very similar to the other K dwarf systems discovered by TESS, TOI-2202 and TOI-216, which are composed of almost identical K dwarf primaries and two warm giant planets near the 2:1 MMR.Item Vetting of 384 TESS Objects of Interest with TRICERATOPS and Statistical Validation of 12 Planet Candidates(IOP Publishing, 2020-12-11) Giacalone, Steven; Dressing, Courtney D.; Jensen, Eric L. N.; Collins, Karen A.; Ricker, George R.; Vanderspek, Roland; Seager, S.; Winn, Joshua N.; Jenkins, Jon M.; Barclay, Thomas; Barkaoui, Khalid; Cadieux, Charles; Charbonneau, David; Collins, Kevin I.; Conti, Dennis M.; Doyon, René; Evans, Phil; Ghachoui, Mourad; Gillon, Michaël; Guerrero, Natalia M.; Hart, Rhodes; Jehin, Emmanuël; Kielkopf, John F.; McLean, Brian; Murgas, Felipe; Palle, Enric; Parviainen, Hannu; Pozuelos, Francisco J.; Relles, Howard M.; Shporer, Avi; Socia, Quentin; Stockdale, Chris; Tan, Thiam-Guan; Torres, Guillermo; Twicken, Joseph D.; Waalkes, William C.; Waite, Ian A.We present TRICERATOPS, a new Bayesian tool that can be used to vet and validate TESS Objects of Interest (TOIs). We test the tool on 68 TOIs that have been previously confirmed as planets or rejected as astrophysical false positives. By looking in the false-positive probability (FPP)−nearby false-positive probability (NFPP) plane, we define criteria that TOIs must meet to be classified as validated planets (FPP < 0.015 and NFPP < 10⁻³), likely planets (FPP < 0.5 and NFPP < 10⁻³), and likely nearby false positives (NFPP > 10⁻¹). We apply this procedure on 384 unclassified TOIs and statistically validate 12, classify 125 as likely planets, and classify 52 as likely nearby false positives. Of the 12 statistically validated planets, 9 are newly validated. TRICERATOPS is currently the only TESS vetting and validation tool that models transits from nearby contaminant stars in addition to the target star. We therefore encourage use of this tool to prioritize follow-up observations that confirm bona fide planets and identify false positives originating from nearby stars.