Photometric analysis of the system Kepler-1
[ X ]
Tarih
2016
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Springer
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
We have applied the close binary system analysis program WINFITTER to an intensive study of Kepler-1 (= TrES-2) using all the available photometry (14 quarters; 1570640 measures) from the NASA Exoplanet Archive (NEA) at the Caltech website http://exoplanetarchive.ipac.caltech.edu. The mean individual data-point error of the normalized flux values is 0.00026, leading to the model's specification for the mean reference flux of the system to an accuracy of similar to 0.5 ppm. Completion of the analysis requires a number of prior quantities, relating mainly to the host star, that are adopted from relevant literature. Our new results tend broadly to confirm those of previous authors, though there are a number of significant differences. Specifically, the applied photometric fitting function is more precise than those used before on the full Kepler data-set. The more complete discussion of the interdependent role of errors, using MCMC sampling, allows greater confidence in the obtained parameters themselves as well as understanding or their likely errors. Our photometrically derived values for the mass and radius of Kepler-1b are 1.18 +/- 0.05 M-Jup and 1.21 +/- 0.05 R-Jup. The mass of this Safronov Class I planet is closer to published spectroscopic values than found from previous photometric analysis, which can be attributed to the improved fitting function. The analysis determines a definite photometric Doppler effect from the orbit, but this is not independent of the tidal ('ellipticity') effect, and the two are consistently combined in our fitting function. A corresponding rotation-related Rossiter effect was not detected, allowing an upper limit on the rotation speed of similar to 70 kms(-1). The proportion of light coming from the known companion star is resolved, but turns out rather less than that inferred from the results of direct measurement. The fitting function also predicts a small secondary minimum ('occultation'), when the light reflected by the planet is eclipsed. However, the occultation depth cannot be measured directly from the data to the relevant accuracy, and so models for the planet's atmospheric properties based on this will be compromised by other assumptions and approximations in the light curve's fitting function. Suggestions of secular trends for the variation of parameters are considered, but the evidence of the Kepler data is not yet very persuasive.
Açıklama
Anahtar Kelimeler
Stars - binary, Exoplanets, Light curve analysis
Kaynak
Astrophysics and Space Science
WoS Q DeÄŸeri
Q3
Scopus Q DeÄŸeri
Cilt
361
Sayı
10
