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

By W. Cochran, D. Fabrycky, G. Torres, F. Fressin, J. D'esert, D. Ragozzine, D. Sasselov, Jon Fortney, J. Rowe, E. Brugamyer and 44 more. 2011

157 citations recorded by the source corpus.

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 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⊕, a radius of 2.00 ± 0.10 R⊕, and a mean density of 4.9 ± 2.4 g cm3. 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 ± 0.07 g cm3, 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 ± 0.03 g cm3. Kepler-18c and Kepler-18d have orbital periods near a 2:1 mean-motion resonance, leading to large and readily detected TTVs.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/97895dff2af7f07afe2535087b929a45edb40ed3

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In Astronomy and Astrophysics

1. D. Charbonneau
2. Timothy Morton
3. Jon Fortney
4. G. Marcy
5. J. Johnson
6. J. Winn
7. Andrew W. Howard
8. J. Owen

In Instrumentation

1. D. Charbonneau
2. Timothy Morton
3. Jon Fortney
4. G. Marcy
5. J. Owen
6. J. Johnson
7. Andrew W. Howard
8. J. Winn

Citations in the corpus

• Transit timing observations from Kepler - VII. Confirmation of 27 planets in 13 multiplanet systems via transit timing variations and orbital stability (2012, methodology): “, Kepler 11 (Lissauer et al. 2011a), Kepler 18 (Cochran et al. 2011), and Kepler 36 (Carter et al. 2012)), 21 planets in 10 multiplanet systems have been confirmed by these new methods that we apply again here (Kepler systems 23 through 32, Fabrycky et al. (2012a); Ford et al. (2012a); Steffen et…”
• ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS (2012, background): “Note that this multiplicity boost incorporates self-consistently both the coplanarity boost discussed in Cochran et al. (2011) and the systems boost (that planets tend to come in systems) without need to disentangle these effects.”
• Kepler-22b: A 2.4 EARTH-RADIUS PLANET IN THE HABITABLE ZONE OF A SUN-LIKE STAR (2011, unknown): “However, others, such as Kepler-18b have a size (Rp = 1.98 R⊕) similar to Kepler-22b and a density (4.9 ± 2.4 g/cc) sufficiently high to imply that such planets could have a solid or liquid surface.”
• KEPLER PLANETS: A TALE OF EVAPORATION (2013, background): “The same density and radius trends are encapsulated in many of the Kepler multi-planet systems, e.g., Kepler-11 (Lissauer et al. 2011), Kepler-18 (Cochran et al. 2011), Kepler-20 (Gautier et al. 2012) & Kepler-36 (Carter et al. 2012), as well as reported by recent radial velocity studies (Weiss et a”
• AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES (2012, background): “…transit timing variations (TTVs) that may be used to dynamically confirm the planets in the system (Holman et al. 2010; Lissauer et al. 2011; Cochran et al. 2011; Fabrycky et al. 2012; Ford et al. 2012; Steffen et al. 2012), but the number of systems for which this is feasible is still an…”
• TRANSIT TIMING OBSERVATIONS FROM KEPLER. VIII. CATALOG OF TRANSIT TIMING MEASUREMENTS OF THE FIRST TWELVE QUARTERS (2013, background): “Indeed, TTVs turn out to be a crucial tool in the study of systems with known multiple transiting planets (e.g., Holman et al. 2010; Lissauer et al. 2011a; Cochran et al. 2011; Fabrycky et al. 2012; Steffen et al. 2012a; Lithwick et al. 2012).”
• THE MASS OF KOI-94d AND A RELATION FOR PLANET RADIUS, MASS, AND INCIDENT FLUX (2013, methodology): “…by one of two methods: the majority were measured as MPsini based on the radial velocity of the star; however, in several Kepler systems of multiple planets, TTVs aided (Cochran et al. 2011, Kepler-18) or provided the sole means (Lissauer et al. 2011, Kepler-11) of planetary mass calculation.”
• EXTRACTING PLANET MASS AND ECCENTRICITY FROM TTV DATA (2012, methodology): “To break it, additional information or assumptions are required, e.g., radial velocity measurements or the stability of the planetary system (Cochran et al. 2011; Fabrycky et al. 2012a).”
• Kepler Planet Masses and Eccentricities from TTV Analysis (2016, methodology): “Kepler-18 was previously analyzed by Cochran et al. (2011), who fit both RV and TTV observations of Kepler-18 spanning Quarters 0–6.”
• THE RADIUS DISTRIBUTION OF PLANETS AROUND COOL STARS (2013, background): “…Institute of Technology, MC 249-17, Pasadena, CA 91125 multi systems have been measured from the effects of mutual gravitational interactions (e.g. Cochran et al. 2011, Lithwick et al. 2012, Nesvorny et al. 2013) providing insight into the composition and atmospheric evolution of these planets…”
• THE FALSE POSITIVE RATE OF KEPLER AND THE OCCURRENCE OF PLANETS (2013, methodology): “…observations, and BLENDER studies have shown that such scenarios are often the most common blend configuration for candidates that have been carefully vetted (see, e.g., Batalha et al. 2011; Cochran et al. 2011; Ballard et al. 2011; Fressin et al. 2012; Gautier et al. 2012; Borucki et al. 2012); 3.”
• Characterization of exoplanets from their formation - II. The planetary mass-radius relationship (2012, methodology): “We derive a heavy element fraction of 0.43 to 0.52 (MZ= 7.1 to 8.5 M⊕), similar as in Cochran et al. (2011) who find a MZ = 10.4 ± 1.4M⊕.”
• LOW FALSE POSITIVE RATE OF KEPLER CANDIDATES ESTIMATED FROM A COMBINATION OF SPITZER AND FOLLOW-UP OBSERVATIONS (2015, unknown): “These are Kepler-10c (Fressin et al. 2011), Kepler11b (Lissauer et al. 2011), Kepler-14b (Buchhave et al. 2011), Kepler-18b,c (Cochran et al. 2011), Kepler19b Ballard et al. (2011), Kepler-20b,c Gautier et al. (2012), Kepler-22b (Borucki et al. 2012), Kepler25b,c (Steffen et al. 2012), Kepler-26c (S”
• HOW THERMAL EVOLUTION AND MASS-LOSS SCULPT POPULATIONS OF SUPER-EARTHS AND SUB-NEPTUNES: APPLICATION TO THE KEPLER-11 SYSTEM AND BEYOND (2012, unknown): “These include Kepler-11b, Kepler-18b, and 55 Cancri e.”
• ALL SIX PLANETS KNOWN TO ORBIT KEPLER-11 HAVE LOW DENSITIES (2013, methodology): “…e (Winn et al. 2011; Endl et al. 2012), Kepler-20 b (Gautier et al. 2012), and GJ 3470 b (Bonfils et al. 2012); three using TTVs: Kepler-36 b and c (Carter et al. 2012), and Kepler-30 b (Sanchis-Ojeda et al. 2012); and one, Kepler-18 b (Cochran et al. 2011), using a combination of RV and TTV data.”
• TRANSIT TIMING OBSERVATIONS FROM KEPLER. IX. CATALOG OF THE FULL LONG-CADENCE DATA SET (2016, background): “(1) Cochran et al. (2011), (2) Xie (2014), (3) Rowe et al. (2014), (4) Lissauer et al. (2011a), (5) Ford et al. (2012a), (6) Steffen et al. (2012a), (7) Steffen et al. (2013), (8) Carter et al. (2012), (9) Kipping et al. (2014), (10) Holman et al. (2010), (11) Masuda (2014), (12) Fabrycky et al.…”