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

Cochran, W.D., MacQueen, P.J., Endl, M., Fabrycky, D.C., Fortney, J.J., Miller, N., Torres, G., Fressin, F., Désert, J.-M., Ragozzine, D., Sasselov, D., Carter, J.A., Quinn, S.N., Latham, D.W., Holman, M.J., Charbonneau, D., Rowe, J.F., Bryson, S.T., Howell, S.B., Borucki, W.J., Koch, D.G., Uddin, K., Tenenbaum, P., Still, M., Mullally, F., Lissauer, J.J., Kinemuchi, K., Jenkins, J.M., Henze, C.E., Haas, M.R., Caldwell, D., Brugamyer, E.J., Ciardi, D.R., Steffen, J.H., Winn, J.N., Seager, S., Demory, B.-O., Welsh, W.F., Uddin, K., Tenenbaum, P., Mullally, F., Jenkins, J.M., Caldwell, D., Still, M., Kinemuchi, K., Marcy, G.W., Knutson, H., Isaacson, H., Howard, A., Lucas, P.W., Johnson, J.A., Horch, E., Gilliland, R.L., Gautier, T.N., Ford, E.B., Fischer, D.A., Everett, M., Deming, D., Buchhave, L., Brown, T.M. and Batalha, N. (2011) 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. Astrophysical Journal, Supplement Series, 197 (1): 7. ISSN 0067-0049

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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 ± 2.4gcm. 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 , 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 ± 0.03gcm. Kepler-18c and Kepler-18d have orbital periods near a 2:1 mean-motion resonance, leading to large and readily detected TTVs.

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Keywords	planetary systems, stars: individual (kepler-18, kic 8644288, 2mass j19521906+4444467), techniques: photometric, techniques: spectroscopic
Date Deposited	15 May 2025 12:17
Last Modified	30 May 2025 23:48