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
- McDonald Observatory, University of Texas, Austin, TX 78712 (United States)
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
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{sub sun}, a radius of 1.1 R{sub sun}, an effective temperature of 5345 K, 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{sub +}, a radius of 2.00 {+-} 0.10 R{sub +}, and a mean density of 4.9 {+-} 2.4 g cm{sup 3}. 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{sub +}, a radius of 5.49 {+-} 0.26 R{sub +}, and a mean density of 0.59 {+-} 0.07 g cm{sup 3}, while Kepler-18d has a mass of 16.4 {+-} 1.4 M{sub +}, a radius of 6.98 {+-} 0.33 R{sub +} and a mean density of 0.27 {+-} 0.03 g cm{sup 3}. Kepler-18c and Kepler-18d have orbital periods near a 2:1 mean-motion resonance, leading to large and readily detected TTVs.
- OSTI ID:
- 21562415
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 197, Issue 1; Other Information: DOI: 10.1088/0067-0049/197/1/7; ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
Similar Records
HAT-P-18b AND HAT-P-19b: TWO LOW-DENSITY SATURN-MASS PLANETS TRANSITING METAL-RICH K STARS
Planet hunters. VII. Discovery of a new low-mass, low-density planet (PH3 C) orbiting Kepler-289 with mass measurements of two additional planets (PH3 B and D)