Browsing by Author "Seager, S"

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    A unique solution of planet and star parameters from an extrasolar planet transit light curve
    (2003) Seager, S; Mallén-Ornelas, G
    There is a unique solution of the planet and star parameters from a planet transit light curve with two or more transits if the planet has a circular orbit and the light curve is observed in a bandpass where limb darkening is negligible. The existence of this unique solution is very useful for current planet transit surveys for several reasons. First, there is an analytic solution that allows a quick parameter estimate, in particular of R-p. Second, the stellar density can be uniquely derived from the transit light curve alone. The stellar density can then be used to immediately rule out a giant star ( and hence a much larger than planetary companion) and can also be used to put an upper limit on the stellar and planet radius even considering slightly evolved stars. Third, the presence of an additional fully blended star that contaminates an eclipsing system to mimic a planet transit can be largely ruled out from the transit light curve given a spectral type for the central star. Fourth, the period can be estimated from a single-transit light curve and a measured spectral type. All of these applications can be used to select the best planet transit candidates for mass determination by radial velocity follow-up. To use these applications in practice, the photometric precision and time sampling of the light curve must be high (better than 0.005 mag precision and 5 minute time sampling for a two-transit light curve).
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    HD 213885b: a transiting 1-d-period super-Earth with an Earth-like composition around a bright (V=7.9) star unveiled by TESS
    (2020) Espinoza, N; Brahm Scott, Rafael; Henning, T; Jordán Colzani, Andrés Cristóbal; Dorn, C; Rojas, F; Sarkis, P; Kossakowski, D; Schlecker, M; Diaz, MR; Jenkins, JS; Aguilera-Gomez, C; Jenkins, JM; Twicken, JD; Collins, KA; Lissauer, J; Armstrong, DJ; Adibekyan, V; Barrado, D; Barros, SCC; Battley, M; Bayliss, D; Bouchy, F; Bryant, EM; Cooke, BF; Demangeon, ODS; Dumusque, X; Figueira, P; Giles, H; Lillo-Box, J; Lovis, C; Nielsen, LD; Pepe, F; Pollaco, D; Santos, NC; Sousa, SG; Udry, S; Wheatley, PJ; Turner, O; Marmier, M; Segransan, D; Ricker, G; Latham, D;; Seager, S; Winn, JN; Kielkopf, JF; Hart, R; Wingham, G; Jensen, ELN; Helminiak, Krzysztof Grzegorz; Tokovinin, A; Briceno, C; Ziegler, C; Law, NM; Mann, AW; Daylan, T; Doty, JP; Guerrero, N; Boyd, P; Crossfield, I; Morris, RL; Henze, CE; Chacon, AD
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    The EXPLORE project.: I.: A deep search for transiting extrasolar planets
    (2003) Mallén-Ornelas, G; Seager, S; Yee, HKC; Minniti, D; Gladders, MD; Mallén-Fullerton, GM; Brown, TM
    Planet transit searches promise to be the next breakthrough for extrasolar planet detection and will bring the characterization of short-period planets into a new era. Every transiting planet discovered will have a measured radius, which will provide constraints on planet composition, evolution, and migration history. Together with radial velocity measurements, the absolute mass of every transiting planet will be determined. In this paper we discuss the design considerations of the Extrasolar Planet Occultation Research (EXPLORE) project, a series of transiting planet searches using 4 m class telescopes to continuously monitor a single field of stars in the Galactic plane in each similar to2 week observing campaign. We discuss the general factors that determine the efficiency and the number of planets found by a transit search, including time sampling strategy and field selection. The primary goal is to select the most promising planet candidates for radial velocity follow-up observations. We show that with very high photometric precision light curves that have frequent time sampling and at least two detected transits, it is possible to uniquely solve for the main parameters of the eclipsing system (including planet radius), based on several important assumptions about the central star. Together with a measured spectral type for the star, this unique solution for orbital parameters provides a powerful method for ruling out most contaminants to transiting planet candidates. For the EXPLORE project, radial velocity follow-up observations for companion mass determination of the best candidates are done on 8 m class telescopes within 2 or 3 months of the photometric campaigns. This same-season follow-up is made possible by the use of efficient pipelines to produce high-quality light curves within weeks of the observations. We conclude by presenting early results from our first search, EXPLORE I, in which we reached better than 1% rms photometric precision (measured over a full night) on similar to37,000 stars with 14.5less than or equal toIless than or equal to18.2.
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    TOI-954 b and K2-329 b: Short-period Saturn-mass Planets that Test whether Irradiation Leads to Inflation
    (2021) Sha, LZ; Huang, CLX; Shporer, A; Rodriguez, JE; Vanderburg, A; Brahm, R; Hagelberg, J; Matthews, EC; Ziegler, C; Livingston, JH; Stassun, KG; Wright, DJ; Crane, JD; Espinoza, N; Bouchy, F; Bakos, GA; Collins, KA; Zhou, GR; Bieryla, A; Hartman, JD; Wittenmyer, RA; Nielsen, LD; Plavchan, P; Bayliss, D; Sarkis, P; Tan, TG; Cloutier, R; Mancini, L; Jordan, A; Wang, SR; Henning, T; Narita, N; Penev, K; Teske, JK; Kane, SR; Mann, AW; Addison, BC; Tamura, M; Horner, J; Barbieri, M; Burt, JA; Diaz, MR; Crossfield, IJM; Dragomir, D; Drass, H; Feinstein, AD; Zhang, H; Hart, R; Kielkopf, JF; Jensen, ELN; Montet, BT; Ottoni, G; Schwarz, RP; Rojas Henríquez, Felipe Ignacio; Nespral, D; Torres Miranda, Pascal Jose; Mengel, MW; Udry, S; Zapata, A; Snoddy, E; Okumura, J; Ricker, GR; Vanderspek, RK; Latham, DW; Winn, JN; Seager, S; Jenkins, JM; Colon, KD; Henze, CE; Krishnamurthy, A; Ting, EB; Vezie, M; Villanueva, S
    We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of 0.852(-0.062)(+0.053) R-J and a mass of 0.174(-0.017)(+0.018) M-J and is in a 3.68 day orbit, while K2-329 b has a radius of 0.774(-0.024)(+0.026) R-J and a mass if 0.260(-0.022)(+0.020) M-J and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes.