Disproving the validated planets K2-78b, K2-82b, and K2-92b

CABRERA, J.; BARROS, S. C. C.; ARMSTRONG, D.; HIDALGO, D.; SANTOS, N. C.; ALMENARA, J. M.; ALONSO, R.; DELEUIL, M.; DEMANGEON, O.; DÍAZ, R. F.; LENDL, M.; PFAFF, J.; RAUER, H.; SANTERNE, A.; SERRANO, L. M.; ZUCKER, S.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2017 vol. 606

0004-6361

Context. Transiting super-Earths orbiting bright stars in short orbitalperiods are interesting targets for the study of planetary atmospheres. Aims: While selecting super-Earths suitable for furthercharacterisation from the ground from a list of confirmed and validatedexoplanets detected by K2, we found some suspicious cases that led to usreassess the nature of the detected transiting signal. Methods:We performed a photometric analysis of the K2 light curves and centroidmotions of the photometric barycenters. Results: Our study showsthat the validated planets K2-78b, K2-82b, and K2-92b are not planets,but background eclipsing binaries. The eclipsing binaries are inside theKepler photometric aperture, but outside the ground-basedhigh-resolution images that were used for validation. Conclusions: We advise extreme care in the validation of candidateplanets that are discovered by space missions. It is important that allthe assumptions in the validation process are carefully checked. Anindependent confirmation is mandatory in order to avoid wasting valuableresources on further characterisation of non-existent targets.