@article{5447189473bf4ef8a63f6c03a572691f,
title = "Kepler-18b,c, and d: a system of three planets confirmed by transit timing variations, light curve validation, Warm-Spitzer photometry, and radial velocity measurements",
abstract = "We report the detection of three transiting planets around a Sun-like star, which we designate Kepler-18. The transit signals were detected in photometric data from the Kepler satellite, and were confirmed to arise from planets using a combination of large transit-timing variations (TTVs), radial velocity variations, Warm-Spitzer observations, and statistical analysis of false-positive probabilities. The Kepler-18 star has a mass of 0.97 M ⊙, a radius of 1.1 R ⊙, an effective temperature of 5345K, and an iron abundance of [Fe/H] = +0.19. The planets have orbital periods of approximately 3.5, 7.6, and 14.9 days. The innermost planet {"}b{"} is a {"}super-Earth{"} with a mass of 6.9 ± 3.4 M ⊕, a radius of 2.00 ± 0.10 R ⊕, and a mean density of 4.9 ± 2.4gcm3. The two outer planets {"}c{"} and {"}d{"} are both low-density Neptune-mass planets. Kepler-18c has a mass of 17.3 ± 1.9 M ⊕, a radius of 5.49 ± 0.26 R ⊕, and a mean density of 0.59 0.07gcm 3, while Kepler-18d has a mass of 16.4 ± 1.4 M ⊕, a radius of 6.98 ± 0.33 R ⊕ and a mean density of 0.27 ± 0.03gcm3. Kepler-18c and Kepler-18d have orbital periods near a 2:1 mean-motion resonance, leading to large and readily detected TTVs.",
author = "Cochran, {William D.} and Fabrycky, {Daniel C.} and Guillermo Torres and Fran{\c c}ois Fressin and Jean-Michel Desert and Darin Ragozzine and Dimitar Sasselov and Fortney, {Jonathan J.} and Rowe, {Jason F.} and Brugamyer, {Erik J.} and Bryson, {Stephen T.} and Carter, {Joshua A.} and Ciardi, {David R.} and Howell, {Steve B.} and Steffen, {Jason H.} and Borucki, {William J.} and Koch, {David G.} and Winn, {Joshua N.} and Welsh, {William F.} and Kamal Uddin and Peter Tenenbaum and M. Still and Sara Seager and Quinn, {Samuel N.} and F. Mullally and Niel Miller and Marcy, {Geoffrey W.} and MacQueen, {Phillip J.} and Phillip Lucas and Lissauer, {Jack J.} and Latham, {David W.} and Heather Knutson and K. Kinemuchi and Johnson, {John A.} and Jenkins, {Jon M.} and Howard Isaacson and Andrew Howard and Elliott Horch and Holman, {Matthew J.} and Henze, {Christopher E.} and Haas, {Michael R.} and Gilliland, {Ronald L.} and Gautier, {Thomas N.} and Ford, {Eric B.} and Fischer, {Debra A.} and Mark Everett and Michael Endl and Brice-Oliver Demory and Drake Deming and David Charbonneau and Douglas Caldwell and Buchhave, {Lars A.} and Brown, {Timothy M.} and Natalie Batalha",
year = "2011",
month = nov,
day = "1",
doi = "10.1088/0067-0049/197/1/7",
language = "English",
volume = "197",
journal = "Astrophysical Journal, Supplement Series",
issn = "0067-0049",
publisher = "Institute of Physics Publishing, Inc",
number = "1",
}